Vehicle lighting fixture
09869443 ยท 2018-01-16
Assignee
Inventors
Cpc classification
F21S41/365
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/67
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/25
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/255
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/16
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/663
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/675
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/176
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/68
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
B60Q1/06
PERFORMING OPERATIONS; TRANSPORTING
F21S41/20
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/33
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/285
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
Abstract
A vehicle lighting fixture can include a plurality of light sources; a plurality of optical deflectors provided to correspond to the light sources, the optical deflector configured to include a mirror part; a screen member configured to form a luminance distribution assigned to each optical deflector with the scanning light by the mirror part of the optical deflector; an optical system configured to project the luminance distributions on the screen member to thereby form a predetermined light distribution pattern; a changing unit configured to change the luminance distribution assigned to each of the optical deflectors; and a control unit configured to control the light sources and the optical deflectors so that the optical deflectors each can form the respective luminance distributions assigned to the respective optical deflectors on the screen member. The changing unit can change the respective luminance distributions assigned to the respective optical deflectors at a prescribed timing.
Claims
1. A vehicle lighting fixture configured to form a predetermined light distribution pattern, the vehicle lighting fixture comprising: a plurality of light sources; a plurality of optical deflectors provided to correspond to the plurality of light sources, the optical deflector configured to include a mirror part that can scan with light from a corresponding one of the light sources; a screen member configured to form a luminance distribution assigned to each of the optical deflectors with the scanning light by the mirror part of the optical deflector; an optical system configured to project the luminance distributions formed on the screen member to thereby form the predetermined light distribution pattern; a changing unit configured to change the luminance distribution assigned to each of the optical deflectors; and a control unit configured to control the plurality of light sources and the plurality of optical deflectors so that the plurality of optical deflectors each can form the respective luminance distributions assigned to the respective optical deflectors on the screen member, wherein the changing unit is configured to change the respective luminance distributions assigned to the respective optical deflectors at a prescribed timing, and the changing unit is configured to change the luminance distributions assigned to the respective optical deflectors to luminance distributions with different sizes from each other among the optical deflectors and that are luminance distributions different in size from those previously assigned to the respective optical deflectors before the predetermined timing.
2. The vehicle lighting fixture according to claim 1, wherein the plurality of optical deflectors includes a first optical deflector, a second optical deflector, and a third optical deflector, and the changing unit is configured to change the luminance distributions formed by the respective optical deflectors to a first luminance distribution having a first size, a second luminance distribution having a second size smaller than the first size and configured to overlap the first luminance distribution, and a third luminance distribution having a third size smaller than the second size and configured to overlap the second luminance distribution.
3. The vehicle lighting fixture according to claim 2, wherein each of the plurality of light sources is configured by any of a semiconductor light emitting element and a combination of a light emitting element and an optical fiber guiding light from the light emitting element, wherein the optical fiber has a light incident end face and a light exiting end face, and the light exiting end face is located at a light source position.
4. The vehicle lighting fixture according to claim 3, wherein the vehicle lighting fixture has a reference axis so that the optical system, the screen member, and the plurality of optical deflectors are disposed along the reference axis in this order; the plurality of light sources is disposed to surround the reference axis and is inclined so that each of the light sources emits light rearward and directed to the reference axis; and the plurality of optical deflectors is disposed to be closer to the reference axis than the plurality of light sources and surround the reference axis so that the light from the corresponding one of the light sources is incident on the corresponding one of the mirror parts and is reflected by the mirror part to be directed to the screen member.
5. The vehicle lighting fixture according to claim 2, wherein the vehicle lighting fixture has a reference axis so that the optical system, the screen member, and the plurality of optical deflectors are disposed along the reference axis in this order; the plurality of light sources is disposed to surround the reference axis and is inclined so that each of the light sources emits light rearward and directed to the reference axis; and the plurality of optical deflectors is disposed to be closer to the reference axis than the plurality of light sources and surround the reference axis so that the light from the corresponding one of the light sources is incident on the corresponding one of the mirror parts and is reflected by the mirror part to be directed to the screen member.
6. The vehicle lighting fixture according to claim 1, wherein each of the plurality of light sources is configured by any of a semiconductor light emitting element and a combination of a light emitting element and an optical fiber guiding light from the light emitting element, wherein the optical fiber has a light incident end face and a light exiting end face, and the light exiting end face is located at a light source position.
7. The vehicle lighting fixture according to claim 6, wherein the vehicle lighting fixture has a reference axis so that the optical system, the screen member, and the plurality of optical deflectors are disposed along the reference axis in this order; the plurality of light sources is disposed to surround the reference axis and is inclined so that each of the light sources emits light rearward and directed to the reference axis; and the plurality of optical deflectors is disposed to be closer to the reference axis than the plurality of light sources and surround the reference axis so that the light from the corresponding one of the light sources is incident on the corresponding one of the mirror parts and is reflected by the mirror part to be directed to the screen member.
8. The vehicle lighting fixture according to claim 1, wherein the vehicle lighting fixture has a reference axis so that the optical system, the screen member, and the plurality of optical deflectors are disposed along the reference axis in this order; the plurality of light sources is disposed to surround the reference axis and is inclined so that each of the light sources emits light rearward and directed to the reference axis; and the plurality of optical deflectors is disposed to be closer to the reference axis than the plurality of light sources and surround the reference axis so that the light from the corresponding one of the light sources is incident on the corresponding one of the mirror parts and is reflected by the mirror part to be directed to the screen member.
9. The vehicle lighting fixture according claim 1, wherein the optical system is a projector lens that can be configured by a plurality of lenses so as to compensate aberration to form a flat image plane, and the screen member is configured to be a flat shape and disposed along the flat image plane.
10. A vehicle lighting fixture configured to form a predetermined light distribution pattern, the vehicle lighting fixture comprising: a plurality of light sources; a plurality of optical deflectors provided to correspond to the plurality of light sources, the optical deflector configured to include a mirror part that can scan with light from a corresponding one of the light sources; a screen member configured to form a luminance distribution assigned to each of the optical deflectors with the scanning light by the mirror part of the optical deflector; an optical system configured to project the luminance distributions formed on the screen member to thereby form the predetermined light distribution pattern; a changing unit configured to change the luminance distribution assigned to each of the optical deflectors; and a control unit configured to control the plurality of light sources and the plurality of optical deflectors so that the plurality of optical deflectors each can form the respective luminance distributions assigned to the respective optical deflectors on the screen member, wherein the changing unit is configured to change the respective luminance distributions assigned to the respective optical deflectors at a prescribed timing, and the plurality of optical deflectors includes a first optical deflector, a second optical deflector, and a third optical deflector, and the changing unit is configured to change the luminance distributions formed by the respective optical deflectors to a first luminance distribution having a first size, a second luminance distribution having a second size smaller than the first size and configured to overlap the first luminance distribution, and a third luminance distribution having a third size smaller than the second size and configured to overlap the second luminance distribution.
11. The vehicle lighting fixture according to claim 10, wherein each of the plurality of light sources is configured by any of a semiconductor light emitting element and a combination of a light emitting element and an optical fiber guiding light from the light emitting element, wherein the optical fiber has a light incident end face and a light exiting end face, and the light exiting end face is located at a light source position.
12. The vehicle lighting fixture according to claim 11, wherein the vehicle lighting fixture has a reference axis so that the optical system, the screen member, and the plurality of optical deflectors are disposed along the reference axis in this order; the plurality of light sources is disposed to surround the reference axis and is inclined so that each of the light sources emits light rearward and directed to the reference axis; and the plurality of optical deflectors is disposed to be closer to the reference axis than the plurality of light sources and surround the reference axis so that the light from the corresponding one of the light sources is incident on the corresponding one of the mirror parts and is reflected by the mirror part to be directed to the screen member.
13. The vehicle lighting fixture according to claim 10, wherein the vehicle lighting fixture has a reference axis so that the optical system, the screen member, and the plurality of optical deflectors are disposed along the reference axis in this order; the plurality of light sources is disposed to surround the reference axis and is inclined so that each of the light sources emits light rearward and directed to the reference axis; and the plurality of optical deflectors is disposed to be closer to the reference axis than the plurality of light sources and surround the reference axis so that the light from the corresponding one of the light sources is incident on the corresponding one of the mirror parts and is reflected by the mirror part to be directed to the screen member.
14. A vehicle lighting fixture configured to form a predetermined light distribution pattern, the vehicle lighting fixture comprising: a plurality of light sources; a plurality of optical deflectors provided to correspond to the plurality of light sources, the optical deflector configured to include a mirror part that can scan with light from a corresponding one of the light sources; a screen member configured to form a luminance distribution assigned to each of the optical deflectors with the scanning light by the mirror part of the optical deflector; an optical system configured to project the luminance distributions formed on the screen member to thereby form the predetermined light distribution pattern; a changing unit configured to change the luminance distribution assigned to each of the optical deflectors; and a control unit configured to control the plurality of light sources and the plurality of optical deflectors so that the plurality of optical deflectors each can form the respective luminance distributions assigned to the respective optical deflectors on the screen member, wherein the changing unit is configured to change the respective luminance distributions assigned to the respective optical deflectors at a prescribed timing, and each of the plurality of light sources is configured by any of a semiconductor light emitting element and a combination of a light emitting element and an optical fiber guiding light from the light emitting element, wherein the optical fiber has a light incident end face and a light exiting end face, and the light exiting end face is located at a light source position.
15. The vehicle lighting fixture according to claim 14, wherein the vehicle lighting fixture has a reference axis so that the optical system, the screen member, and the plurality of optical deflectors are disposed along the reference axis in this order; the plurality of light sources is disposed to surround the reference axis and is inclined so that each of the light sources emits light rearward and directed to the reference axis; and the plurality of optical deflectors is disposed to be closer to the reference axis than the plurality of light sources and surround the reference axis so that the light from the corresponding one of the light sources is incident on the corresponding one of the mirror parts and is reflected by the mirror part to be directed to the screen member.
16. A vehicle lighting fixture configured to form a predetermined light distribution pattern, the vehicle lighting fixture comprising: a plurality of light sources; a plurality of optical deflectors provided to correspond to the plurality of light sources, the optical deflector configured to include a mirror part that can scan with light from a corresponding one of the light sources; a screen member configured to form a luminance distribution assigned to each of the optical deflectors with the scanning light by the mirror part of the optical deflector; an optical system configured to project the luminance distributions formed on the screen member to thereby form the predetermined light distribution pattern; a changing unit configured to change the luminance distribution assigned to each of the optical deflectors; and a control unit configured to control the plurality of light sources and the plurality of optical deflectors so that the plurality of optical deflectors each can form the respective luminance distributions assigned to the respective optical deflectors on the screen member, wherein the changing unit is configured to change the respective luminance distributions assigned to the respective optical deflectors at a prescribed timing, and the vehicle lighting fixture has a reference axis so that the optical system, the screen member, and the plurality of optical deflectors are disposed along the reference axis in this order; the plurality of light sources is disposed to surround the reference axis and is inclined so that each of the light sources emits light rearward and directed to the reference axis; and the plurality of optical deflectors is disposed to be closer to the reference axis than the plurality of light sources and surround the reference axis so that the light from the corresponding one of the light sources is incident on the corresponding one of the mirror parts and is reflected by the mirror part to be directed to the screen member.
17. A vehicle lighting fixture configured to form a predetermined light distribution pattern, the vehicle lighting fixture comprising: a plurality of light sources; a plurality of optical deflectors provided to correspond to the plurality of light sources, the optical deflector configured to include a mirror part that can scan with light from a corresponding one of the light sources; a screen member configured to form a luminance distribution assigned to each of the optical deflectors with the scanning light by the mirror part of the optical deflector; an optical system configured to project the luminance distributions formed on the screen member to thereby form the predetermined light distribution pattern; a changing unit configured to change the luminance distribution assigned to each of the optical deflectors; and a control unit configured to control the plurality of light sources and the plurality of optical deflectors so that the plurality of optical deflectors each can form the respective luminance distributions assigned to the respective optical deflectors on the screen member, wherein the changing unit is configured to change the respective luminance distributions assigned to the respective optical deflectors at a prescribed timing, the vehicle lighting fixture further comprising a plurality of reflecting surfaces provided corresponding to the plurality of light sources, and wherein the vehicle lighting fixture has a reference axis so that the optical system, the screen member, and the plurality of optical deflectors are disposed along the reference axis in this order, the plurality of light sources is disposed to surround the reference axis and be inclined so that each of the light sources can emit light forward and directed to the reference axis, the plurality of reflecting surfaces is disposed to be closer to the reference axis than the plurality of light sources, surround the reference axis, and is inclined so that the light from the corresponding one of the light sources can be incident on the corresponding one of the reflecting surfaces and be reflected rearward by the reflecting surface to be directed to the reference axis, and the plurality of optical deflectors is disposed to be closer to the reference axis than the plurality of reflecting surfaces and surround the reference axis so that the light from the corresponding one of the reflecting surfaces is incident on the corresponding one of the mirror parts and is reflected by the mirror part to be directed to the screen member.
18. A vehicle lighting fixture configured to form a predetermined light distribution pattern, the vehicle lighting fixture comprising: a plurality of light sources; a plurality of optical deflectors provided to correspond to the plurality of light sources, the optical deflector configured to include a mirror part that can scan with light from a corresponding one of the light sources; a screen member configured to form a luminance distribution assigned to each of the optical deflectors with the scanning light by the mirror part of the optical deflector; an optical system configured to project the luminance distributions formed on the screen member to thereby form the predetermined light distribution pattern; a changing unit configured to change the luminance distribution assigned to each of the optical deflectors; and a control unit configured to control the plurality of light sources and the plurality of optical deflectors so that the plurality of optical deflectors each can form the respective luminance distributions assigned to the respective optical deflectors on the screen member, wherein the changing unit is configured to change the respective luminance distributions assigned to the respective optical deflectors at a prescribed timing, and each of the optical deflectors is of a one-dimensional nonresonance/one-dimensional resonance type (2-D optical scanner (fast resonant and slow static combination)), including the mirror part; a movable frame disposed to surround the mirror part while supporting the mirror part so as to allow the mirror part to be reciprocately swung about a first axis; a base disposed to surround the movable frame while supporting the movable frame so as to allow the movable frame to be reciprocately swung about a second axis perpendicular to the first axis; a first piezoelectric actuator configured to cause the mirror part to be reciprocally swung about the first axis with respect to the movable frame due to resonance driving; and a second piezoelectric actuator configured to cause the movable frame and the mirror part supported by the movable frame to be reciprocally swung about the second axis with respect to the base due to nonresonance driving, and the vehicle lighting fixture is configured such that each of the plurality of optical deflectors is disposed such that the first axis is contained in a vertical plane and the second axis is contained in a horizontal plane.
19. The vehicle lighting fixture according to claim 18, wherein the light source is an excitation light source, and the screen member is formed from a wavelength converting member.
20. The vehicle lighting fixture according to claim 18, wherein the light source is a white light source and the screen member is formed from a diffusion member.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1) These and other characteristics, features, and advantages of the presently disclosed subject matter will become clear from the following description with reference to the accompanying drawings, wherein:
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DESCRIPTION OF EXEMPLARY EMBODIMENTS
(50) A description will now be made below to vehicle lighting fixtures of the presently disclosed subject matter with reference to the accompanying drawings in accordance with exemplary embodiments. The definition relating to directions is based on the irradiation direction of the vehicle lighting fixture that can form a light distribution pattern in front of a vehicle body on which the vehicle lighting fixture is installed.
(51) Before discussing the presently disclosed subject matter in accordance with exemplary embodiments, the basic configuration that can be adopted by the presently disclosed subject matter will be described as several reference examples with the use of a simple system configuration.
(52)
(53) As illustrated in
(54) The optical deflector 201, the wavelength converting member 18, and the projection lens assembly 20 can be disposed, as illustrated in
(55) The optical deflector 201, the wavelength converting member 18, and the projection lens assembly 20 may be disposed, as illustrated in
(56) The excitation light source 12 can be a semiconductor light emitting element such as a laser diode (LD) that can emit laser light rays of blue color (for example, having an emission wavelength of 450 nm) as excitation light. But the presently disclosed subject matter is not limited thereto. The excitation light source 12 can be a semiconductor light emitting element such as a laser diode (LD) that can emit laser light rays of near ultraviolet light (for example, having an emission wavelength of 405 nm) or an LED. The excitation light rays emitted from the excitation light source 12 can be converged by the condenser lens 14 (for example, collimated) and be incident on the optical deflector 201 (in particular, on a mirror part thereof).
(57) The wavelength converting member 18 can be a plate-shaped or laminate-type wavelength converting member having a rectangular outer shape. The wavelength converting member 18 can be scanned with the laser light rays as the excitation light rays by the optical deflector 201 in a two-dimensional manner (in the horizontal and vertical directions) to thereby convert at least part of the excitation light rays to light rays with different wavelength. In the case of
(58) For example, when the excitation light source 12 is a blue laser diode for emitting blue laser light rays, the wavelength converting member 18 can include a plate-shaped or laminate-type phosphor that can be excited by the blue laser light rays to emit yellow light rays. With this configuration, the optical deflector 201 can scan the wavelength converting member 18 with the blue laser light rays in a two-dimensional manner (in the horizontal and vertical directions), whereby a two-dimensional white image can be drawn on the wavelength converting member 18 corresponding to a predetermined light distribution pattern. Specifically, when the blue laser light rays are irradiated on the wavelength converting member 18, the passing blue laser light rays and the yellow light rays emitted from the wavelength converting member 18 can be mixed together to thereby draw the two-dimensional white image (pseudo white light) on the wavelength converting member 18.
(59) Further, when the excitation light source 12 is a near UV laser diode (LD) for emitting near UV laser light rays, the wavelength converting member 18 can include a plate-shaped or laminate-type phosphor that can be excited by the near UV laser light rays to emit three types of light rays, i.e., red, green, and blue light rays. With this configuration, the optical deflector 201 can scan the wavelength converting member 18 with the near UV laser light rays in a two-dimensional manner (in the horizontal and vertical directions), whereby a two-dimensional white image corresponding to a predetermined light distribution pattern can be drawn on the wavelength converting member 18. Specifically, when the near UV laser light rays are irradiated on the wavelength converting member 18, the red, green, and blue light rays emitted from the wavelength converting member 18 due to the excitation of the phosphor by the near UV laser light rays can be mixed to draw the two-dimensional white image (pseudo white light) on the wavelength converting member 18.
(60) The projection lens assembly 20 can be composed of a group of four lenses 20A to 20D that have been aberration-corrected (have been corrected in terms of the field curvature) to provide a planar image formed, as illustrated in
(61) Further, the projection lens assembly 20 may be composed of a single aspheric lens without aberration correction (correction of the field curvature) to form a planar image. In this case, the wavelength converting member 18 should be a curved one corresponding to the field curvature and disposed along the field curvature. In this case, the focal point F of the projection lens assembly 20 can be located at or near the wavelength converting member 18.
(62) The projection lens assembly 20 can project the two-dimensional image drawn on the wavelength converting member 18 corresponding to the predetermined light distribution pattern forward to thereby form the predetermined light distribution pattern (low-beam light distribution pattern or high-beam light distribution pattern) on a virtual vertical screen assumed to be disposed in front of the vehicle lighting fixture 10 approximately 25 m away from the vehicle body.
(63) Next, a description will be given of the optical deflector 201. The optical deflector 201 can scan the wavelength converting member 18 in a two-dimensional manner (in the horizontal and vertical direction) with the excitation light rays Ray emitted from the excitation light source 12 and converged by the condenser lens 14 (for example, collimated).
(64) The optical deflectors 201 can be configured by, for example, an MEMS scanner. The driving system of the optical deflectors is not limited to a particular system, and examples thereof may include a piezoelectric system, an electrostatic system, and an electromagnetic system. In this reference example, a description will be given of an optical deflector driven by a piezoelectric system as a representative example.
(65) The piezoelectric system used in the optical deflector is not limited to a particular system, and examples thereof may include a one-dimensional nonresonance/one-dimensional resonance type, a two-dimensional nonresonance type, and a two-dimensional resonance type.
(66) The following reference example may employ the one-dimensional nonresonance/one-dimensional resonance type (a 2-D optical scanner (fast resonant and slow static combination)) optical deflector 201, as one example.
(67) <One-Dimensional Nonresonance/One-Dimensional Resonance Type (2-D Optical Scanner (Fast Resonant and Slow Static Combination))>
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(69) As schematically illustrated in
(70) The mirror part 202 can have a circular shape and the torsion bars 211a and 211 b can be connected to the mirror part 202 so as to extend outward from respective ends of the mirror part 202. The first piezoelectric actuators 203 and 204 can be formed in a semi-circular shape so as to surround the mirror part 202 while they are provided with a gap between them. Furthermore, the first piezoelectric actuators 203 and 204 can be connected to each other with the torsion bars 211a and 211b interposed therebetween at their respective ends. The movable frame 212 can be disposed to surround the mirror part 202 and the first piezoelectric actuators 203 and 204. The first piezoelectric actuators 203 and 204 can be connected to and supported by the movable frame 212 at respective outer central portions of the arc (semi-circular) shape.
(71) The movable frame 212 can have a rectangular shape and include a pair of sides disposed in a direction perpendicular to the directions in which the torsion bars 211a and 211b extend. At the pair of sides the movable frame 212 can be connected to the respective tip ends of the second piezoelectric actuators 205 and 206 opposite to each other with the movable frame 212 interposed therebetween. The base 215 can include a supporting base part 214 formed thereon so as to surround the movable frame 212 and the second piezoelectric actuators 205 and 206. The second piezoelectric actuators 205 and 206 can be connected to and supported by the supporting base part 214 at respective base ends thereof.
(72) The first piezoelectric actuators 203 and 204 each can include a single piezoelectric cantilever composed of a support 203a, 204a, a lower electrode 203b, 204b, a piezoelectric body 203c, 204c, and an upper electrode 203d, 204d, as illustrated in
(73) Further, as illustrated in
(74) A description will now be given of the action of the mirror part 202 (swing motion about the first axis X1).
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(76) As illustrated in
(77) A description will now be given of the action of the mirror part 202 (swing motion around a second axis X2).
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(79) As illustrated in
(80) A single support formed by processing a silicon substrate can constitute a mirror part support for the mirror part 202, the torsion bars 211a and 211b, supports for the first piezoelectric actuators 203 and 204, the movable frame 212, supports for the second piezoelectric actuators 205 and 206, and the supporting base part 214 on the base 215. Furthermore, the base 215 can be formed from a silicon substrate, and therefore, it can be integrally formed from the above single support by processing a silicon substrate. As the technique of processing such a silicon substrate, those described in, for example, Japanese Patent Application Laid-Open No. 2008-040240, which is hereby incorporated in its entirety by reference, can be employed. There can be provided a gap between the mirror part 202 and the movable frame 212, so that the mirror part 202 can be swung about the first axis X1 with respect to the movable frame 212 within a predestined angle range. Furthermore, there can be provided a gap between the movable frame 212 and the base 215, so that the movable frame 212 (together with the mirror part 202 supported by the movable frame 212) can be swung about the second axis X2 with respect to the base 215 within a predetermined angle range.
(81) The optical deflector 201 can include electrode sets 207 and 208 to apply a drive voltage to the respective piezoelectric actuators 203 to 206.
(82) The electrode set 207 can include an upper electrode pad 207a, a first upper electrode pad 207b, a second upper electrode pad 207c, and a common lower electrode 207d. The upper electrode pad 207a can be configured to apply a drive voltage to the first piezoelectric actuator 203. The first upper electrode pad 207b can be configured to apply a drive voltage to the odd-numbered piezoelectric cantilevers 205A, 205C, and 205E of the second piezoelectric actuator 205. The second upper electrode pad 207c can be configured to apply a drive voltage to the even-numbered piezoelectric cantilevers 205B, 205D, and 205F of the second piezoelectric actuator 205. The common lower electrode 207d can be used as a lower electrode common to the upper electrode pads 207a to 207c.
(83) In a similar manner, the electrode set 208 can include an upper electrode pad 208a, a first upper electrode pad 208b, a second upper electrode pad 208c, and a common lower electrode 208d. The upper electrode pad 208a can be configured to apply a drive voltage to the first piezoelectric actuator 204. The first upper electrode pad 208b can be configured to apply a drive voltage to the odd-numbered piezoelectric cantilevers 206A, 206C, and 206E of the second piezoelectric actuator 206. The second upper electrode pad 208c can be configured to apply a drive voltage to the even-numbered piezoelectric cantilevers 206B, 206D, and 206F of the second piezoelectric actuator 206. The common lower electrode 208d can be used as a lower electrode common to the upper electrode pads 208a to 208c.
(84) In this reference example, the first piezoelectric actuator 203 can be applied with a first AC voltage as a drive voltage, while the first piezoelectric actuator 204 can be applied with a second AC voltage as a drive voltage, where the first AC voltage and the second AC voltage can be different from each other in phase, such as a sinusoidal wave with an opposite phase or shifted phase. In this case, an AC voltage with a frequency close to a mechanical resonance frequency (first resonance point) of the mirror part 202 including the torsion bars 211a and 211b can be applied to resonantly drive the first piezoelectric actuators 203 and 204. This can cause the mirror part 202 to be reciprocately swung about the first axis X1 with respect to the movable frame 212, so that the laser light rays from the excitation light source 12 and incident on the mirror part 202 can scan in a first direction (for example, in the horizontal direction).
(85) A third AC voltage can be applied to each of the second piezoelectric actuators 205 and 206 as a drive voltage. In this case, an AC voltage with a frequency equal to or lower than a predetermined value that is smaller than a mechanical resonance frequency (first resonance point) of the movable frame 212 including the mirror part 202, the torsion bars 211a and 211b, and the first piezoelectric actuators 203 and 204 can be applied in order to nonresonantly drive the second piezoelectric actuators 205 and 206. This can cause the mirror part 202 to be reciprocately swung about the second axis X2 with respect to the base 215, so that the laser light rays as excitation light rays from the excitation light source 12 and incident on the mirror part 202 can scan in a second direction (for example, in a vertical direction).
(86) The optical deflector 201 utilizing a 2-D optical scanner (fast resonant and slow static combination) can be arranged so that the first axis X1 is contained in a vertical plane and the second axis X2 is contained in a horizontal plane. With this arrangement, a predetermined light distribution pattern (two-dimensional image corresponding to the required predetermined light distribution pattern) being wide in the horizontal direction and narrow in the vertical direction for use in a vehicular headlamp can be easily formed (drawn). The reason therefor will be discussed next.
(87) Specifically, the optical deflector 201 utilizing a 2-D optical scanner (fast resonant and slow static combination) can be configured such that the maximum swing angle of the mirror part 202 about the first axis X1 is larger than the maximum swing angle of the mirror part 202 about the second axis X2. For example, since the reciprocal swing movement of the mirror part 202 about the first axis X1 is caused due to the resonance driving, the maximum swing angle of the mirror part 202 about the first axis X1 ranges from 10 degrees to 20 degrees as illustrated in
(88) As described above, by driving the respective piezoelectric actuators 203 to 206, the laser light rays from the excitation light source 12 as the excitation light rays can scan in a two dimensional manner (for example, in the horizontal and vertical directions).
(89) As illustrated in
(90) The H sensor 220 can be formed from a piezoelectric element (PZT) similar to the piezoelectric cantilever included in the first piezoelectric actuators 203 and 204 and can be configured to generate a voltage in accordance with the bent deformation (amount of displacement) of the first piezoelectric actuators 203 and 204. The V sensor 222 can be formed from a piezoelectric element (PZT) similar to the piezoelectric cantilever included in the second piezoelectric actuators 205 and 206 and can be configured to generate a voltage in accordance with the bent deformation (amount of displacement) of the second piezoelectric actuators 205 and 206.
(91) In the optical deflector 201, the mechanical swing angle (half angle) of the mirror part 202 about the first axis X1 is varied, as illustrated in
(92) A description will next be given of the desired frequencies of the first AC voltage and the second AC voltage to be applied to the first piezoelectric actuators 203 and 204 and the desired frequency of the third AC voltage to be applied to the second piezoelectric actuators 205 and 206.
(93) Some experiments were conducted and the test results thereof were examined to find out that the frequencies (hereinafter, referred to as a horizontal scanning frequency f.sub.H) of the first AC voltage and the second AC voltage to be applied to the first piezoelectric actuators 203 and 204 in the optical deflector 201 utilizing a 2-D optical scanner (fast resonant and slow static combination) with the above configuration can be desirably about 4 to 30 kHz (sinusoidal wave), and more desirably 27 kHz+3 kHz (sinusoidal wave).
(94) Furthermore, it has been found out that the horizontal resolution (number of pixels) is desirably set to 300 (or more) in consideration of the high-beam light distribution pattern so that the turning ON/OFF (lighting or not lighting) can be controlled at an interval of 0.1 degrees (or less) within the angular range of 15 degrees (left) to +15 degrees (right) with respect to the vertical axis V.
(95) Further experiments were conducted and the test results thereof were examined to find out that the frequency (hereinafter, referred to as a vertical scanning frequency f.sub.V) of the third AC voltage to be applied to the second piezoelectric actuators 205 and 206 in the optical deflector 201 utilizing a 2-D optical scanner (fast resonant and slow static combination) with the above configuration can be desirably 55 Hz or higher (sawtooth wave), more desirably 55 Hz to 120 Hz (sawtooth wave), still more desirably 55 Hz to 100 Hz (sawtooth wave), and particularly desirably 70 Hz10 Hz (sawtooth wave).
(96) Furthermore, it has been found out that the frequency (the vertical scanning frequency f.sub.V) of the third AC voltage to be applied to the second piezoelectric actuators 205 and 206 is set to desirably 50 Hz or higher (sawtooth wave), more desirably 50 Hz to 120 Hz (sawtooth wave), still more desirably 50 Hz to 100 Hz (sawtooth wave), and particularly desirably 70 Hz10 Hz (sawtooth wave) in consideration of normal travelling speeds (for example, 0 km/h to 150 km/h). Since the frame rate depends on the vertical scanning frequency f.sub.V, when the vertical scanning frequency f.sub.V is 70 Hz, the frame rate is 70 fps.
(97) When the vertical scanning frequency f.sub.V is 55 Hz or higher, the predetermined light distribution pattern can be formed on the virtual vertical screen as an image (may be considered as a moving picture or movie) with a frame rate of 55 fps or more. Similarly, when the vertical scanning frequency f.sub.V is 55 Hz to 120 Hz, the predetermined light distribution pattern can be formed on the virtual vertical screen as an image (may be considered as a moving picture or movie) with a frame rate of 55 fps or more and 120 fps or less. In a similar manner, when the vertical scanning frequency f.sub.V is 55 Hz to 100 Hz, the predetermined light distribution pattern can be formed on the virtual vertical screen as an image (may be considered as a moving picture or movie) with a frame rate of 55 fps or more and 100 fps or less. Similarly, when the vertical scanning frequency f.sub.V is 70 Hz10 Hz, the predetermined light distribution pattern can be formed on the virtual vertical screen as an image (may be considered as a moving picture or movie) with a frame rate of 70 fps10 fps. The same correspondence as above can be applied to the cases when the vertical scanning frequency f.sub.V is 50 Hz or more, 50 Hz to 120 Hz, 50 Hz to 100 Hz, and 70 Hz10 Hz.
(98) The resolution (the number of vertical scanning lines) in the vertical direction can be determined by the following formula.
Resolution in the vertical direction (or the number of vertical scanning lines)=2(Utility time coefficient of vertical scanning: K.sub.V)f.sub.H/f.sub.V
(99) On the basis of this formula, if the horizontal scanning frequency f.sub.H=25 kHz, the vertical scanning frequency f.sub.V=70 Hz, and the utility time coefficient K.sub.V=0.9 to 0.8, then the number of vertical scanning lines is about 600 (lines)=225 kHz/70 Hz(0.9 to 0.85).
(100) The above-described desirable vertical scanning frequency f.sub.V has never been used in vehicle lighting fixtures such as vehicle headlamps. Specifically, in the conventional art, in order to suppress the flickering in the general illumination field (other than the vehicle lighting fixtures such as an automobile headlamp), it is a technical common knowledge to use a frequency of 100 Hz or higher. Furthermore, in order to suppress the flickering in the technical field of vehicle lighting fixtures, it is a technical common knowledge to use a frequency of 220 Hz or higher. Therefore, the above-described desirable vertical scanning frequency f.sub.V has never been used in vehicle lighting fixtures such as vehicle headlamps.
(101) Next, a description will now be given of why the technical common knowledge is to use a frequency of 100 Hz or higher in order to suppress the flickering in the general illumination field (other than the vehicle lighting fixtures such as an automobile headlamp).
(102) For example, the Ordinance Concerning Technical Requirements for Electrical Appliances and Materials (Ordinance of the Ministry of International Trade and Industry No. 85 of 37th year of Showa) describes that the light output should be no flickering felt by anyone, and it is interpreted as to be no flickering when the light output has a repeated frequency of 100 Hz or higher without missing parts or has a repeated frequency of 500 Hz or higher. It should be noted that the Ordinance is not intended to vehicle lighting fixtures such as automobile headlamps.
(103) Furthermore, the report in Nihon Keizai Shimbun (The Nikkei dated Aug. 26, 2010) also said that the alternating current has a frequency of 50 Hz. The voltage having passed through a rectifier is repeatedly changed between ON and OFF at a frequency of 100 times per second. The fluctuation in voltage may affect the fluctuation in luminance of fluorescent lamps. An LED illumination has no afterglow time like the fluorescent lamps, but instantaneously changes in its luminance, whereby flickering is more noticeable, meaning that the flickering is more noticeable when the frequency is 100 Hz or higher.
(104) In general, the blinking frequency of fluorescent lamps that cannot cause flickering is said to be 100 Hz to 120 Hz (50 Hz to 60 Hz in terms of the power source phase).
(105) Next, a description will be given of why the technical common knowledge is to use a frequency of 220 Hz or higher (or a frame rate of 220 fps or more) in order to suppress the flickering in vehicle lighting fixtures such as an automobile headlamp.
(106) In general, an HID (metal halide lamp) used for an automobile headlamp can be lit in a condition of applying a voltage with a frequency of 350 to 500 Hz (rectangular wave). This is because a frequency of 800 Hz or more may cause a noise while a lower frequency may deteriorate the light emission efficiency of HIDs. When a frequency of 150 Hz or lower is employed, the HID life may be lowered due to the adverse effect to heating wearing of electrodes. Furthermore, a frequency of 250 Hz or higher is said to be preferable.
(107) The report of Glare-free High Beam with Beam-scanning, ISAL 2013, pp. 340 to 347 says that the frequency for use in a vehicle lighting fixture such as an automobile headlamp is 220 Hz or higher, and the recommended frequency is 300 to 400 Hz or higher. Furthermore, the report Flickering effects of vehicle exterior light systems and consequences, ISAL 2013, pp. 262 to 266 says that the frequency for use in a vehicle lighting fixture such as an automobile headlamp is approximately 400 Hz.
(108) Therefore, it has never been known in the conventional art that the use of frequency of 55 Hz or higher (desirably 55 Hz to 120 Hz) as a vertical scanning frequency f.sub.V in a vehicle lighting fixture such as an automobile headlamp can suppress flickering.
(109) A description will now be given of the experiments conducted in order to study the above-described desirable vertical scanning frequency f.sub.V.
(110) <Experiment>
(111) The conducted experiments used a test system simulating a vehicle headlamp during driving to evaluate the degree of flickering sensed by test subjects.
(112)
(113) As illustrated in
(114) First, experiments were performed to confirm whether the flickering sensed by a test subject is different between a case where the lighting fixture model M having an LED excitation light source is used for illuminating the surface of the rotary belt B and a case where the lighting fixture model M having an LD excitation light source is used for illuminating the surface of the rotary belt B. As a result, it has been confirmed that if the vertical scanning frequency f.sub.V is the same, the degree of flickering sensed by test subjects is not different between the case where the lighting fixture model M having the LED excitation light source is used for illuminating the surface of the rotary belt B and the case where the lighting fixture model M having the LD excitation light source is used for illuminating the surface of the rotary belt B.
(115) Next, the vertical scanning frequency f.sub.V was measured at the time when a test subject did not sense the flickering while the rotary belt B was being rotated at different rotational speed corresponding to each of actual travelling speeds, 0 km/h, 50 km/h, 100 km/h, 150 km/h, and 200 km/h. In particular, the test experiment was performed in such a manner that a test subject changed the vertical scanning frequency f.sub.V by dial operation and stopped the dial operation when he/she did not sense the flickering. The vertical scanning frequency measured at that time was regarded as the vertical scanning frequency f.sub.V. The measurement was performed at some levels of illuminance. They are: illuminance of 60 1 being the comparable level of road illumination in front of a vehicle body 30 to 40 m away from the vehicle body (at an area which a driver watches during driving); illuminance of 300 1 being the comparable level of road illumination in front of the vehicle body approximately 10 m away from the vehicle body (at an area just in front of the vehicle body); and illuminance of 2000 1 being the comparable level of reflection light from a preceding vehicle or a guard rail close to the vehicle body.
(116) With reference to
(117) First, when the road illuminance is 60 1 and the travelling speed is 0 km/h to 200 km/h, the vertical scanning frequency f.sub.V at which a person does not sense flickering is 55 kHz or higher. In consideration of the road illuminance of 60 1 at an area which a driver watches during driving, it is desirable to set the vertical scanning frequency f.sub.V at 55 kHz or higher in order to suppress the flickering occurring in a vehicle lighting fixture such as an automobile headlamp.
(118) Second, when the road illuminance is 60 1 and the travelling speed is 0 km/h to 150 km/h, the vertical scanning frequency f.sub.V at which a person does not sense flickering is 50 kHz or higher. In consideration of the road illuminance of 60 1 at an area which a driver watches during driving, it is desirable to set the vertical scanning frequency f.sub.V at 50 kHz or higher in order to suppress the flickering occurring in a vehicle lighting fixture such as an automobile headlamp.
(119) Third, when the travelling speed is increased, the vertical scanning frequency f.sub.V at which a person does not sense flickering tends to increase. Taking it into consideration, it is desirable to make the vertical scanning frequency f.sub.V variable in order to suppress the occurrence of flickering in a vehicle lighting fixture such as an automobile headlamp. For example, it is desirable to increase the vertical scanning frequency f.sub.V as the travelling speed is increased.
(120) Fourth, when the illuminance is increased, the vertical scanning frequency f.sub.V at which a person does not sense flickering tends to increase. Taking it into consideration, it is desirable to make the vertical scanning frequency f.sub.V variable in order to suppress the occurrence of flickering in a vehicle lighting fixture such as an automobile headlamp. For example, it is desirable to increase the vertical scanning frequency f.sub.V as the illuminance is increased.
(121) Fifth, the vertical scanning frequency f.sub.V at which a person does not sense flickering is higher at the time of stopping (0 km/h) than at the time of travelling (50 km/h to 150 km/h). Taking it into consideration, it is desirable to make the vertical scanning frequency f.sub.V variable in order to suppress the occurrence of flickering in a vehicle lighting fixture such as an automobile headlamp. For example, it is desirable to make the relationship between the vertical scanning frequency f.sub.V1 during stopped and the vertical scanning frequency f.sub.V2 during travelling f.sub.V1>f.sub.V2.
(122) Sixth, the vertical scanning frequency f.sub.V at which a person does not sense flickering is not higher than 70 kHz at illuminance of 60 1, 300 1, or 2000 1 and at the time of travelling (0 km/h to 200 km/h). Taking it into consideration, it is desirable to set the vertical scanning frequency f.sub.V to 70 kHz or higher or 70 Hz10 Hz in order to suppress the occurrence of flickering in a vehicle lighting fixture such as an automobile headlamp.
(123) Furthermore, it has been found that the frequency (the vertical scanning frequency f.sub.V) of the third AC voltage to be applied to the second piezoelectric actuators 205 and 206 is set to desirably 120 Hz or lower (sawtooth wave), and more desirably 100 Hz or lower (sawtooth wave), when taking the mechanical resonance point (hereinafter referred to as V-side resonance point) of the movable frame 212 including the mirror part 202, the torsion bars 211a and 211b, and the first piezoelectric actuators 203 and 204 into consideration. The reason is as follows.
(124)
(125) For example, when a voltage of about 2 V is applied to the second piezoelectric actuators 205 and 206 (low voltage activation), as illustrated in
(126) A description will next be given of the configuration example of a controlling system configured to control the excitation light source 12 and the optical deflector 201, which is illustrated in
(127) As illustrated in
(128) The MEMS power circuit 26 can function as a piezoelectric actuator controlling unit (or mirror part controlling unit) in accordance with the control by the controlling unit 24. The MEMS power circuit 26 can be configured to apply the first and second AC voltages (for example, sinusoidal wave of 25 MHz) to the first piezoelectric actuators 203 and 204 to resonantly drive the first piezoelectric actuators 203 and 204, so that the mirror part 202 can be reciprocally swung about the first axis X1. The MEMS power circuit 26 can be further configured to apply the third AC voltage (for example, sawtooth wave of 55 Hz) to the second piezoelectric actuators 205 and 206 to none-resonantly drive the second piezoelectric actuators 205 and 206, so that the mirror part 202 can be reciprocally swung about the second axis X2.
(129) In
(130)
(131) The LD power circuit 28 can function as a modulation unit configured to modulate the excitation light source 12 (laser light rays) in synchronization with the reciprocating swing movement of the mirror part 202 in accordance with the control by the controlling unit 24.
(132) The modulation frequency (modulation rate) of the excitation light source 12 (laser light rays) can be determined by the following formula.
Modulation Frequency f.sub.L=(number of pixels)(frame rate: f.sub.V)/(ratio of blanking time: Br).
(133) On the basis of this formula, if the number of pixels is 300600, f.sub.V=70, and Br=0.5, then the modulation frequency f.sub.L is approximately 25 MHz=30060070/0.5. If the modulation frequency f.sub.L is approximately 25 MHz, the output of the excitation light source 12 can be controlled to turn ON/OFF the light source or emit light rays with various intensities in plural stepped degrees per 1/25 MHz seconds (for example, zero is minimum and a plurality of stepwisely increased intensities).
(134) The LD power circuit 28 can modulate the excitation light source 12 (laser light rays) on the basis of a predetermined light distribution pattern (digital data) stored in the storage device 44 so that a two-dimensional image corresponding to the predetermined light distribution pattern is drawn on the wavelength converting member 18 by means of laser light rays as excitation light with which the optical deflector 201 two-dimensionally scans (in the horizontal and vertical directions).
(135) Examples of the predetermined light distribution pattern (digital data) may include a high-beam light distribution pattern (digital data), a low-beam distribution pattern (digital data), a highway driving light distribution pattern (digital data), and a town-area driving light distribution pattern (digital data). The predetermined light distribution patterns (digital data) can include the outer shapes of respective light distribution patterns, light intensity distributions (illuminance distribution), and the like. As a result, the two-dimensional image drawn on the wavelength converting member 18 by means of laser light rays as excitation light with which the optical deflector 201 two-dimensionally scans (in the horizontal and vertical directions) can have the outer shape corresponding to the light distribution pattern (for example, high-beam light distribution pattern) and the light intensity distribution (for example, the light intensity distribution with a maximum value at its center required for such a high-beam light distribution pattern). Note that the switching between various predetermined light distribution patterns (digital data) can be performed by operating a selector switch to be provided within a vehicle interior.
(136)
(137) Examples of the scanning patterns in the horizontal direction of laser light (spot-shaped laser light) scanned by the optical deflector 201 in a two-dimensional manner (in the horizontal direction and the vertical direction) may include the pattern with bidirectional scanning (reciprocating scanning) as illustrated in
(138) Furthermore, examples of the scanning patterns in the vertical direction of laser light (spot-shaped laser light) scanned by the optical deflector 201 in a two-dimensional manner (in the horizontal direction and the vertical direction) may include the pattern densely scanned one line by one line, and the pattern scanned every other line similar to the interlace scheme as illustrated in
(139) Furthermore, examples of the scanning patterns in the vertical direction of laser light (spot-shaped laser light) scanned by the optical deflector 201 in a two-dimensional manner (in the horizontal direction and the vertical direction) may include the pattern in which the optical deflector scans from the upper end to the lower end repeatedly, as illustrated in
(140) Incidentally, when the scanning reaches the left, right, upper, or lower end of the wavelength converting member 18 (screen), the scanning light may be returned to the original starting point or another designated point. This time period is called as blanking, during which the excitation light source 12 is not lit.
(141) A description will next be given of other examples of control by the controlling system illustrated in
(142) The controlling system illustrated in
(143) Furthermore, on the basis of the fact where when the travelling speed is increased, the vertical scanning frequency f.sub.V at which a person does not sense flickering tends to increase, the driving frequency (vertical scanning frequency f.sub.V) for nonresonantly driving the second piezoelectric actuators 205 and 206 can be changed on the basis of the travelling speed as a result of detection by the speed sensor 34 provided to the vehicle body. For example, it is possible to increase the vertical scanning frequency f.sub.V as the traveling speed increases. When doing so, the correspondence between the vertical scanning frequencies f.sub.V and the traveling speeds (or ranges of traveling speed) is stored in the storage device 44 in advance (meaning that the relationship of the increased vertical scanning frequency f.sub.V corresponding to the increased travelling speed or range is confirmed in advance). Then, the vertical scanning frequency f.sub.V is read out from the storage device 44 on the basis of the detected vehicle traveling speed detected by the speed sensor 34. After that, the MEMS power circuit 26 can apply the third AC voltage (with the read-out vertical scanning frequency) to the second piezoelectric actuators 205 and 206 to thereby nonresonantly drive the second piezoelectric actuators 205 and 206.
(144) Furthermore, on the basis of the fact where the vertical scanning frequency f.sub.V at which a person does not sense flickering is higher at the time of stopping (0 km/h) than at the time of travelling (50 km/h to 150 km/h), the vertical scanning frequency f.sub.V at the time of stopping (0 km/h) can be increased as compared with that at the time of travelling (50 km/h to 150 km/h). This can be achieved by the following method. That is, for example, the vertical scanning frequency f.sub.V1 at the time of stopping and the vertical scanning frequency f.sub.V2 at the time of traveling are stored in the storage device 44 in advance (f.sub.V1>f.sub.V2), and it is determined whether the vehicle body is stopped or not on the basis of the detection results from the speed sensor 34. When it is determined that the vehicle body is traveling, the vertical scanning frequency f.sub.V2 at the time of traveling is read out from the storage device 44. After that, the MEMS power circuit 26 can apply the third AC voltage (with the read-out vertical scanning frequency f.sub.V2 at the time of traveling) to the second piezoelectric actuators 205 and 206 to thereby nonresonantly drive the second piezoelectric actuators 205 and 206. On the other hand, when it is determined that the vehicle body is stopped, the vertical scanning frequency f.sub.V1 at the time of stopping is read out from the storage device 44. After that, the MEMS power circuit 26 can apply the third AC voltage (with the read-out vertical scanning frequency f.sub.V1 at the time of stopping) to the second piezoelectric actuators 205 and 206 to thereby nonresonantly drive the second piezoelectric actuators 205 and 206.
(145) Furthermore, on the basis of the fact where when the illuminance is increased, the vertical scanning frequency f.sub.V at which a person does not sense flickering tends to increase, the driving frequency (vertical scanning frequency f.sub.V) for nonresonantly driving the second piezoelectric actuators 205 and 206 can be changed on the basis of the illuminance detected by the illumination sensor 32 provided to the vehicle body (for example, the illuminance sensed by a driver). For example, it is possible to increase the vertical scanning frequency f.sub.V as the illuminance increases. When doing so, the correspondence between the vertical scanning frequencies f.sub.V and the illuminances (or ranges of illuminance) is stored in the storage device 44 in advance (meaning that the relationship of the increased vertical scanning frequency f.sub.V corresponding to the increased illuminance or range is confirmed in advance). Then, the vertical scanning frequency f.sub.V is read out from the storage device 44 on the basis of the detected illuminance value detected by the illuminance sensor 32. After that, the MEMS power circuit 26 can apply the third AC voltage (with the read-out vertical scanning frequency f.sub.V) to the second piezoelectric actuators 205 and 206 to thereby nonresonantly drive the second piezoelectric actuators 205 and 206.
(146) In the same manner, the driving frequency (vertical scanning frequency f.sub.V) for nonresonantly driving the second piezoelectric actuators 205 and 206 can be changed on the basis of the distance between the vehicle body and an object to be irradiated with light detected by the distance sensor 38 provided to the vehicle body.
(147) In the same manner, the driving frequency (vertical scanning frequency f.sub.V) for nonresonantly driving the second piezoelectric actuators 205 and 206 can be changed on the basis of the detection results by the vibration sensor 42 provided to the vehicle body.
(148) In the same manner, the driving frequency (vertical scanning frequency f.sub.V) for nonresonantly driving the second piezoelectric actuators 205 and 206 can be changed according to a predetermined light distribution pattern. For example, the driving frequency (vertical scanning frequency f.sub.V) for nonresonantly driving the second piezoelectric actuators 205 and 206 can be changed between the highway driving light distribution pattern and the town-area driving light distribution pattern.
(149) By making the vertical scanning frequency f.sub.V variable as described above, the optical deflector 201 can be improved in terms of the reliability, durability, life time, etc. when compared with the case where the driving frequency for nonresonantly driving the second piezoelectric actuators 205 and 206 is made constant.
(150) In place of the optical deflector 201 of the one-dimensional nonresonance/one-dimensional resonance type (2-D optical scanner (fast resonant and slow static combination)) with the above-described configuration, a two-dimensional nonresonance type optical deflector 161 can be utilized.
(151) <Two-Dimensional Nonresonance Type>
(152)
(153) As illustrated in
(154) The configuration and action of the piezoelectric actuators 163 to 166 can be the same as those of the second piezoelectric actuators 205 and 206 of the optical deflector 201 of the one-dimensional nonresonance/one-dimensional resonance type.
(155) In this reference example, each of first piezoelectric actuators 163 and 164 out of the piezoelectric actuators 163 to 166 can be applied with a first AC voltage as its driving voltage. At this time, the applied voltage can be an alternating voltage with a frequency equal to or lower than a predetermined value smaller than the mechanical resonance frequency (first resonance point) of the mirror part 162 to thereby nonresonantly drive the first piezoelectric actuators 163 and 164. This can cause the mirror part 162 to be reciprocately swung about the third axis X3 with respect to the movable frame 171, so that the excitation light rays from the excitation light source 12 and incident on the mirror part 162 can scan in a first direction (for example, in the horizontal direction).
(156) Furthermore, a second AC voltage can be applied to each of the second piezoelectric actuators 165 and 166 as a drive voltage. At this time, the applied voltage can be an alternating voltage with a frequency equal to or lower than a predetermined value smaller than the mechanical resonance frequency (first resonance point) of the movable frame 171 including the mirror part 162 and the first piezoelectric actuators 165 and 166 to thereby nonresonantly drive the movable frame 171. This can cause the mirror part 162 to be reciprocately swung about the fourth axis X4 with respect to the base 174, so that the excitation light rays from the excitation light source 12 and incident on the mirror part 162 can scan in a second direction (for example, in the vertical direction).
(157)
(158) The respective piezoelectric actuators 163 to 166 can be driven, so that the laser light rays as the excitation light rays from the excitation light source 12 can scan two-dimensionally (in the horizontal and vertical directions).
(159) In place of the optical deflector 201 of the one-dimensional nonresonance/one-dimensional resonance type (2-D optical scanner (fast resonant and slow static combination)) with the above-described configuration, a two-dimensional resonance type optical deflector 201A can be utilized.
(160) <Two-Dimensional Resonance Type>
(161)
(162) As illustrated in
(163) The configuration and action of the piezoelectric actuators 15Aa, 15Ab, 17Aa, and 17Ab can be the same as those of the first piezoelectric actuators 203 and 204 of the optical deflector 201 of the one-dimensional nonresonance/one-dimensional resonance type.
(164) In this reference example, the first piezoelectric actuator 15Aa can be applied with a first AC voltage as its driving voltage while the other first piezoelectric actuator 15Ab can be applied with a second AC voltage as its driving voltage. Here, the first AC voltage and the second AC voltage can be different from each other in phase, such as a sinusoidal wave with an opposite phase or shifted phase. In this case, an AC voltage with a frequency close to a mechanical resonance frequency (first resonance point) of the mirror part 13A including the torsion bars 14Aa and 14Ab can be applied to resonantly drive the first piezoelectric actuators 15Aa and 15Ab. This can cause the mirror part 13A to be reciprocately swung about the fifth axis X5 with respect to the movable frame 12A, so that the laser light rays as excitation light rays from the excitation light source 12 and incident on the mirror part 13A can scan in a first direction (for example, in the horizontal direction).
(165) A third AC voltage can be applied to the second piezoelectric actuator 17Aa as a drive voltage while a fourth AC voltage can be applied to the other second piezoelectric actuator 17Ab as a drive voltage. Here, the third AC voltage and the fourth AC voltage can be different from each other in phase, such as a sinusoidal wave with an opposite phase or shifted phase. In this case, an AC voltage with a frequency near the mechanical resonance frequency (first resonance point) of the movable frame 12A including the mirror part 13A and the first piezoelectric actuators 15Aa and 15Ab can be applied to resonantly drive the first piezoelectric actuators 17Aa and 17Ab. This can cause the mirror part 13A to be reciprocately swung about the sixth axis X6 with respect to the base 11A, so that the laser light rays as excitation light rays from the excitation light source 12 and incident on the mirror part 13A can scan in a second direction (for example, in the vertical direction).
(166)
(167) The respective piezoelectric actuators 15Aa, 15Ab, 17Aa, and 17Ab can be driven, so that the laser light rays as the excitation light rays from the excitation light source 12 can scan two-dimensionally (in the horizontal and vertical directions).
(168) As described above, according to this reference example, even when frequencies remarkably lower than 220 Hz that is conventionally considered to cause the flickering to occur in vehicle lighting fixtures such as an automobile headlamp are utilized or frame rates remarkably lower than 220 fps, i.e., 55 fps or more, 55 fps to 120 fps, 55 fps to 100 fps, or 70 fps10 fps are utilized, the occurrence of flickering can be suppressed.
(169) Furthermore, according to this reference example, frequencies remarkably lower than 220 Hz are utilized (or frame rates remarkably lower than 220 fps), i.e., 55 fps or more, 55 fps to 120 fps, 55 fps to 100 fps, or 70 fps10 fps are utilized, and thus it is possible to improve the reliability, durability, and life time of the optical deflector 201 when compared with the case where the frequency of 220 Hz or higher or frame rates of 220 fps or more are used.
(170) Furthermore, according to this reference example, the drive frequency used for nonresonantly driving the second piezoelectric actuators 205 and 206 can be made variable, and therefore, the reliability, durability, and life time of the optical deflector 201 can be improved when compared with the case where the drive frequency used for nonresonantly driving the second piezoelectric actuators 205 and 206 are constant.
(171) A description will now be given of a vehicle lighting unit using three optical deflectors 201 of one-dimensional nonresonance/one-dimensional resonance type (2-D optical scanner (fast resonant and slow static combination)) with reference to the associated drawings as another reference example. It is appreciated that the aforementioned various types of optical deflectors discussed in the above reference examples can be used in place of the one-dimensional nonresonance/one-dimensional resonance type optical deflector 201.
(172)
(173) As illustrated in
(174) Next, the vehicle lighting fixture 300 of this reference example can be configured to form a predetermined light distribution pattern P will be compared with the vehicle lighting fixture 10 of the previously described reference examples. In the previously described reference example as illustrated in
(175) The configuration of the vehicle lighting fixture 300 of this reference example can have the same configuration as that of the vehicle lighting fixture 10 of the previously described reference example except for the above different point. Hereinbelow, a description will be given of the different point of this reference example from the previously described reference example, and the same or similar components of this reference example as those of the previously described reference example will be denoted by the same reference numerals and a description thereof will be omitted as appropriate.
(176) In the specification, the term hot-zone member/part means a member/part for use in forming a hot-zone partial light distribution pattern (with highest intensity), the term middle-zone member/part means a member/part for use in forming a middle-zone partial light distribution pattern (having a wider area and formed by light diffused more than the hot-zone partial light distribution pattern), and the term wide-zone member/part means a member/part for use in forming a wide-zone partial light distribution pattern (having a more wider area and formed by light diffused more than the middle-zone partial light distribution pattern), unless otherwise specified.
(177) The vehicle lighting fixture 300 can be configured, as illustrated in
(178) As illustrated in
(179) The vehicle lighting fixture 300 can further include a laser holder 46. The laser holder 46 can hold the excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot with a posture tilted in such a manner that excitation light rays Ray.sub.Wide, Ray.sub.Mid, and Ray.sub.Hot are directed rearward and toward the reference axis AX while the excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot surround the reference axis AX.
(180) Specifically, the excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot, can be disposed by being fixed to the laser holder 46 in the following manner.
(181) As illustrated in
(182) As illustrated in
(183) The vehicle lighting fixture 300 can further include the lens holder 56 to which the projection lens assembly 20 (lenses 20A to 20D) is fixed. The lens holder 56 can be screwed at its rear end to the opening of the tubular part 48 so as to be fixed to the tubular part 48.
(184) A condenser lens 14 can be disposed in front of each of the excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot. The excitation light rays Ray.sub.Wide, Ray.sub.Mid, and Ray.sub.Hot can be output from the excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot and condensed by the respective condenser lenses 14 (for example, collimated) to be incident on the respective mirror parts 202 of the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot.
(185) As illustrated in
(186) Specifically, the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot, can be secured to an optical deflector holder 58 as follows.
(187) The optical deflector holder 58 can have a square pyramid shape projected forward, and its front face can be composed of an upper face 58U, a lower face 58D, a left face 58L, and a right face 58R (not shown in the drawings), as illustrated in
(188) The wide-zone optical deflector 201.sub.Wide (corresponding to the first optical deflector in the presently disclosed subject matter) can be secured to the lower face 58D of the square pyramid face while being tilted so that the mirror part 202 thereof is positioned in an optical path of the excitation light rays Ray.sub.Wide output from the wide-zone excitation light source 12.sub.Wide. Similarly thereto, the middle-zone optical deflector 201.sub.Mid (corresponding to the second optical deflector in the presently disclosed subject matter) can be secured to the upper face 58U of the square pyramid face while being tilted so that the mirror part 202 thereof is positioned in an optical path of the excitation light rays Ray.sub.Mid output from the middle-zone excitation light source 12.sub.Mid. Similarly thereto, the hot-zone optical deflector 201.sub.Hot (corresponding to the third optical deflector in the presently disclosed subject matter) can be secured to the left face 58L (when viewed from front) of the square pyramid face while being tilted so that the mirror part 202 thereof is positioned in an optical path of the excitation light rays Ray.sub.Hot output from the hot-zone excitation light source 12.sub.Hot.
(189) The optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot each can be arranged so that the first axis X1 is contained in a vertical plane and the second axis X2 is contained in a horizontal plane. As a result, the above-described arrangement of the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot can easily form (draw) a predetermined light distribution pattern (two-dimensional image corresponding to the required predetermined light distribution pattern) being wide in the horizontal direction and narrow in the vertical direction required for a vehicular headlight.
(190) The wide-zone optical deflector 201.sub.Wide can draw a first two-dimensional image on the wide-zone scanning area A.sub.Wide (corresponding to the first scanning area in the presently disclosed subject matter) with the excitation light rays Ray.sub.Wide two-dimensionally scanning in the horizontal and vertical directions by the mirror part 202 thereof, to thereby form a first light intensity distribution on the wide-zone scanning area A.sub.Wide.
(191) The middle-zone optical deflector 201.sub.Mid can draw a second two-dimensional image on the middle-zone scanning area A.sub.Mid (corresponding to the second scanning area in the presently disclosed subject matter) with the excitation light rays Ray.sub.Mid two-dimensionally scanning in the horizontal and vertical directions by the mirror part 202 thereof in such a manner that the second two-dimensional image overlaps the first two-dimensional image in part, to thereby form a second light intensity distribution on the middle-zone scanning area A.sub.Mid with a higher light intensity than that of the first light intensity distribution.
(192) As illustrated in
(193) The hot-zone optical deflector 201.sub.Hot can draw a third two-dimensional image on the hot-zone scanning area A.sub.Hot (corresponding to the third scanning area in the presently disclosed subject matter) with the excitation light rays Ray.sub.Hot two-dimensionally scanning in the horizontal and vertical directions by the mirror part 202 thereof in such a manner that the third two-dimensional image overlaps the first and second two-dimensional images in part, to thereby form a third light intensity distribution on the hot-zone scanning area A.sub.Hot with a higher light intensity than that of the second light intensity distribution.
(194) As illustrated in
(195) The shape of each of the illustrated scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot in
(196)
(197) The illustrated wavelength converting member 18 can be configured to be a rectangular plate with a horizontal length of 18 mm and a vertical length of 9 mm. The wavelength converting member 18 can also be referred to as a phosphor panel.
(198) As illustrated in
(199) The wavelength converting member 18 can be disposed to be confined between the center line AX.sub.202 of the mirror part 202 of the wide-zone optical deflector 201.sub.Wide at the maximum deflection angle h_max (see
tan(h_max)L/d(Formula 1), and
tan(v_max)S/d(Formula 2),
(200) wherein L is of a horizontal length of the wavelength converting member 18, S is of a vertical length of the wavelength converting member 18, and d is the distance from the wavelength converting member 18 to the optical deflector 201 (mirror part 202).
(201) A description will next be given of how to adjust the sizes (horizontal length and vertical length) of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot.
(202) The sizes (horizontal length and vertical length) of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot can be adjusted by changing the swinging ranges of the mirror parts 202 of the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot about the first axis X1 and the swinging ranges of the mirror parts 202 of the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot about the second axis X2. This can be done by changing the first and second AC voltages to be applied to the first piezoelectric actuators 203 and 204 and the third AC voltage to be applied to the second piezoelectric actuators 205 and 206 when the distances between each of the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot (the center of the mirror part 202) and the wavelength converting member 18 are the same (or substantially the same) as each other. (See
(203) Specifically, as illustrated in
(204) Thus, when the distances between each of the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot (the center of the mirror part 202 thereof) and the wavelength converting member 18 are the same (or substantially the same) as each other (see
(205) Next, a description will be given of a concrete adjustment example. In the following description, it is assumed that the distances between each of the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot (the center of the mirror part 202 thereof) and the wavelength converting member 18 are the same (or substantially the same) as each other and d=24.0 mm as illustrated in
(206) As shown in the row WIDE of the table of (a) of
(207) The L and h_max described in (a) of
(208) As shown in the row WIDE of the table of (b) of
(209) The S and v_max described in (b) of
(210) As described above, 5.41 V.sub.pp as a drive voltage (the first and second AC voltages) is applied to the first piezoelectric actuators 203 and 204 of the wide-zone optical deflector 201.sub.Wide, and 41.2 V.sub.pp as a drive voltage (the third AC voltage) is applied to the second piezoelectric actuators 205 and 206 of the wide-zone optical deflector 201.sub.Wide, thereby changing the swinging range of the mirror part 202 of the wide-zone optical deflector 201.sub.Wide about the first axis X1 and the swinging range of the mirror part 202 of the wide-zone optical deflector 201.sub.Wide about the second axis X2. In this manner, the size (horizontal length) of the wide-zone scanning area A.sub.Wide can be adjusted to be 8.57 mm and the size (vertical length) of the wide-zone scanning area A.sub.Wide can be adjusted to be 3.65 mm to form a rectangular shape with the horizontal length of 8.57 mm and the vertical length of 3.65 mm.
(211) The light intensity distribution formed in the wide-zone scanning area A.sub.wide with the above-described dimensions can be projected forward through the projection lens assembly 20 to thereby form the wide-zone light distribution pattern P.sub.Wide with a rectangle of the width of 15 degrees in the horizontal direction and the width of 6.5 degrees in the vertical direction on the virtual vertical screen (see
(212) As shown in the row MID of the table of (a) of
(213) As shown in the row MID of the table of (b) of
(214) As described above, 2.31 V.sub.pp as a drive voltage (the first and second AC voltages) is applied to the first piezoelectric actuators 203 and 204 of the middle-zone optical deflector 201.sub.Mid, and 24.4 V.sub.pp as a drive voltage (the third AC voltage) is applied to the second piezoelectric actuators 205 and 206 of the middle-zone optical deflector 201.sub.Mid, thereby changing the swinging range of the mirror part 202 of the middle-zone optical deflector 201.sub.Mid about the first axis X1 and the swinging range of the mirror part 202 of the middle-zone optical deflector 201.sub.Mid about the second axis X2. In this manner, the size (horizontal length) of the middle-zone scanning area A.sub.Mid can be adjusted to be 4.78 mm and the size (vertical length) of the middle-zone scanning area A.sub.Mid can be adjusted to be 1.96 mm to form a rectangular shape with the horizontal length of 4.78 mm and the vertical length of 1.96 mm.
(215) The light intensity distribution formed in the middle-zone scanning area A.sub.Mid with the above-described dimensions can be projected forward through the projection lens assembly 20 to thereby form the middle-zone light distribution pattern P.sub.Mid (see
(216) As shown in the row HOT of the table of (a) of
(217) As shown in the row HOT of the table of (b) of
(218) As described above, 0.93 V.sub.pp as a drive voltage (the first and second AC voltages) is applied to the first piezoelectric actuators 203 and 204 of the hot-zone optical deflector 201.sub.Hot, and 13.3 V.sub.pp as a drive voltage (the third AC voltage) is applied to the second piezoelectric actuators 205 and 206 of the hot-zone optical deflector 201.sub.Hot, thereby changing the swinging range of the mirror part 202 of the hot-zone optical deflector 201.sub.Hot about the first axis X1 and the swinging range of the mirror part 202 of the hot-zone optical deflector 201.sub.Hot about the second axis X2. In this manner, the size (horizontal length) of the hot-zone scanning area A.sub.Hot can be adjusted to be 1.96 mm and the size (vertical length) of the hot-zone scanning area A.sub.Hot can be adjusted to be 0.84 mm to form a rectangular shape with the horizontal length of 1.96 mm and the vertical length of 0.84 mm.
(219) The light intensity distribution formed in the hot-zone scanning area A.sub.Hot with the above-described dimensions can be projected forward through the projection lens assembly 20 to thereby form the hot-zone light distribution pattern P.sub.Hot with a rectangle of the width of 3.5 degrees in the horizontal direction and the width of 1.5 degrees in the vertical direction on the virtual vertical screen (see
(220) Thus, when the distances between each of the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot (the center of the mirror part 202) and the wavelength converting member 18 are the same (or substantially the same) as each other (see
(221) Next, a description will be given of another vehicle lighting fixture using three optical deflectors 201 of one-dimensional nonresonance/one-dimensional resonance type (2-D optical scanner (fast resonant and slow static combination)) as further another reference example that can be employed in the presently disclosed subject matter. Note that the type of the optical deflector 201 is not limited to this, but any of the previously described various optical deflectors as exemplified in the previously described reference example may be adopted.
(222)
(223) The vehicle lighting fixture 400 of this reference example can be configured to form a predetermined light distribution pattern P (for example, high-beam light distribution pattern), as illustrated in
(224) Next, the vehicle lighting fixture 400 of this reference example will be compared with the vehicle lighting fixture 300 of the previously described reference example. In the previously described reference example, as illustrated in
(225) The configuration of the vehicle lighting fixture 400 of this reference example can have the same configuration as that of the vehicle lighting fixture 300 of the previously described reference example except for the above different point. Hereinbelow, a description will be given of the different point of this reference example from the previously described reference example, and the same or similar components of this reference example as those in the previously described reference example will be denoted by the same reference numerals and a description thereof will be omitted as appropriate.
(226) The vehicle lighting fixture 400 can be configured, as illustrated in
(227) As illustrated in
(228) The vehicle lighting fixture 400 can further include a laser holder 46A. The excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot can be disposed to surround the reference axis AX and fixed to the laser holder 46A with a posture tilted in such a manner that excitation light rays Ray.sub.Wide, Ray.sub.Mid, and Ray.sub.Hot are directed forward and toward the reference axis AX.
(229) Specifically, the excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot can be disposed by being fixed to the laser holder 46A in the following manner.
(230) As illustrated in
(231) As illustrated in
(232) The vehicle lighting fixture 400 can further include a lens holder 56 to which the projection lens assembly 20 (lenses 20A to 20D) is fixed. The lens holder 56 can be screwed at its rear end to the opening of a tubular part 48 so as to be fixed to the tubular part 48.
(233) A condenser lens 14 can be disposed in front of each of the excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot. The excitation light rays Ray.sub.Wide, Ray.sub.Mid, and Ray.sub.Hot can be emitted from the respective excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot and condensed by the respective condenser lenses 14 (for example, collimated) to be incident on and reflected by the respective reflecting surfaces 60.sub.Wide, 60.sub.Mid, and 60.sub.Hot, and then be incident on the respective mirror parts 202 of the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot.
(234) As illustrated in
(235) Specifically, the reflecting surfaces 60.sub.Wide, 60.sub.Mid, and 60.sub.Hot, can be secured to the reflector holder 62 as follows.
(236) The reflector holder 62 can include a ring-shaped extension 64 extending from the rear end of the tubular part 48, which extends in the reference axis AX direction, toward the rear and outer side. The ring-shaped extension 64 can have a rear surface tilted so that an inner rim thereof closer to the reference axis AX is positioned more forward than an outer rim thereof, as can be seen from
(237) The wide-zone reflecting surface 60.sub.Wide can be secured to a lower portion of the rear surface of the ring-shaped extension 64 with a tilted posture such that the excitation light rays Ray.sub.Wide can be reflected thereby to be directed in a rearward and obliquely upward direction. Similarly, the middle-zone reflecting surface 60.sub.Mid can be secured to an upper portion of the rear surface of the ring-shaped extension 64 with a tilted posture such that the excitation light rays Ray.sub.Mid can be reflected thereby to be directed in a rearward and obliquely downward direction. Similarly, the hot-zone reflecting surface 60.sub.Hot (not illustrated) can be secured to a left portion of the rear surface of the ring-shaped extension 64 with a tilted posture such that the excitation light rays Ray.sub.Hot can be reflected thereby to be directed in a rearward and obliquely rightward direction (when viewed from its front side).
(238) As illustrated in
(239) Specifically, the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot, can be secured to the optical deflector holder 58 in the same manner as in the previously disclosed reference example.
(240) The wide-zone optical deflector 201.sub.Wide (corresponding to the first optical deflector in the presently disclosed subject matter) can be secured to the lower face 58D of the square pyramid face while being tilted so that the mirror part 202 thereof is positioned in an optical path of the excitation light rays Ray.sub.Wide reflected from the wide-zone reflecting surface 60.sub.Wide. Similarly thereto, the middle-zone optical deflector 201.sub.Mid (corresponding to the second optical deflector in the presently disclosed subject matter) can be secured to the upper face 58U of the square pyramid face while being tilted so that the mirror part 202 thereof is positioned in an optical path of the excitation light rays Ray.sub.Mid reflected from the middle-zone reflecting surface 60.sub.Mid. Similarly thereto, the hot-zone optical deflector 201.sub.Hot (corresponding to the third optical deflector in the presently disclosed subject matter) can be secured to the left face 58L (when viewed from its front side) of the square pyramid face while being tilted so that the mirror part 202 thereof is positioned in an optical path of the excitation light rays Ray.sub.Hot reflected from the hot-zone reflecting surface 60.sub.Hot.
(241) The optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot each can be arranged so that the first axis X1 is contained in a vertical plane and the second axis X2 is contained in a horizontal plane. As a result, the above-described arrangement of the optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot can easily form (draw) a predetermined light distribution pattern (two-dimensional image corresponding to the required predetermined light distribution pattern) being wide in the horizontal direction and narrow in the vertical direction required for a vehicular headlight.
(242) The wide-zone optical deflector 201.sub.Wide can draw a first two-dimensional image on the wide-zone scanning area A.sub.Wide (corresponding to the first scanning area in the presently disclosed subject matter) with the excitation light rays Ray.sub.Wide two-dimensionally scanning in the horizontal and vertical directions by the mirror part 202 thereof, to thereby form a first light intensity distribution on the wide-zone scanning area A.sub.Wide.
(243) The middle-zone optical deflector 201.sub.Mid can draw a second two-dimensional image on the middle-zone scanning area A.sub.Mid (corresponding to the second scanning area in the presently disclosed subject matter) with the excitation light rays Ray.sub.Wide two-dimensionally scanning in the horizontal and vertical directions by the mirror part 202 thereof in such a manner that the second two-dimensional image overlaps the first two-dimensional image in part, to thereby form a second light intensity distribution on the middle-zone scanning area A.sub.Mid with a higher light intensity than that of the first light intensity distribution.
(244) As illustrated in
(245) The hot-zone optical deflector 201.sub.Hot can draw a third two-dimensional image on the hot-zone scanning area A.sub.Hot (corresponding to the third scanning area in the presently disclosed subject matter) with the excitation light rays Ray.sub.Hot two-dimensionally scanning in the horizontal and vertical directions by the mirror part 202 thereof in such a manner that the third two-dimensional image overlaps the first and second two-dimensional images in part, to thereby form a third light intensity distribution on the hot-zone scanning area A.sub.Hot with a higher light intensity than that of the second light intensity distribution.
(246) As illustrated in
(247) The shape of each of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot illustrated in
(248) The vehicle lighting fixture 400 can include a phosphor holder 52 to which the wavelength converting member 18 can be secured as in the previously disclosed reference example.
(249) In this reference example, the sizes (horizontal length and vertical length) of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot can be adjusted by the same technique as in the previously disclosed reference example.
(250) With the vehicle lighting fixture having the above-described configuration in this reference example, which utilizes a plurality of optical deflectors configured to scan with excitation light in a two-dimensional manner, it is possible to miniaturize its size and reduce the parts number, which has been a cause for cost increase, as in the previously disclosed reference example.
(251) With the vehicle lighting fixture having the above-described configuration in this reference example, which utilizes a plurality of optical deflectors configured to scan with excitation light in a two-dimensional manner, as illustrated in
(252) According to this reference example, when compared with the above-described vehicle lighting fixture 300 (lighting unit), although the efficiency may be slightly lowered due to the additional reflection, the vehicle lighting fixture 400 can be miniaturized in the up-down and left-right directions (vertical and horizontal direction).
(253) A description will now be given of a modified example.
(254) The above-described reference examples have dealt with the cases where the semiconductor light emitting elements that can emit excitation light rays are used as the excitation light sources 12 (12.sub.Wide, 12.sub.Mid, and 12.sub.Hot), but the presently disclosed subject matter is not limited thereto.
(255) For example, as the excitation light sources 12 (12.sub.Wide, 12.sub.Mid, and 12.sub.Hot), output end faces Fa of optical fibers F that can output excitation light rays from a single excitation light source or a plurality of respective excitation light sources may be used as illustrated in
(256) In particular, when the output end faces Fa of optical fibers F guiding and outputting excitation light are used as the respective excitation light sources 12 (12.sub.Hot, 12.sub.Mid, and 12.sub.Wide), the excitation light source, such as a semiconductor light emitting element, can be disposed at a position away from the main body of the vehicle lighting fixture 10. This configuration can make it possible to further miniaturize the vehicle lighting fixture main body and reduce its weight.
(257)
(258)
(259)
(260) A description will now be given of a technique for forming a high-beam light distribution pattern P.sub.Hi (see
(261) Hereinafter, a description will be given of an example in which the high-beam light distribution pattern P.sub.Hi (see
(262) The vehicle lighting fixture 300 can be configured to include an irradiation-prohibitive object detection unit for detecting an object to which irradiation is prohibited such as a pedestrian and an oncoming vehicle present in front of a vehicle body in which the vehicle lighting fixture 300 is installed. The irradiation-prohibitive object detection unit may be configured to include an imaging device and the like, such as a camera 30 shown in
(263)
(264) As shown in
(265) The non-irradiation regions C1, C2, and C3 each can have a different size, as illustrated in
(266) The non-irradiation regions C1, C2, and C3 (or the non-irradiation region C as a result of the combination) can be formed in respective regions of the plurality of irradiation patterns P.sub.Hot, P.sub.Mid, and P.sub.Wide corresponding to the position where the irradiation-prohibitive object has been detected by the irradiation-prohibitive object detection unit. Specifically, the non-irradiation regions C1, C2, and C3 (or the non-irradiation region C) can be formed in a different region corresponding to the position where the irradiation-prohibitive object is detected. As a result, any glare light toward the irradiation-prohibitive object such as a pedestrian, an oncoming vehicle, etc. can be prevented from being generated.
(267) The plurality of irradiation patterns P.sub.Hot, P.sub.Mid, and P.sub.Wide can have respective different sizes, and can have a higher light intensity as the size thereof is smaller. Due to this configuration, the vehicle lighting fixture 300 can form a high-beam light distribution pattern P.sub.Hi (see
(268) The non-irradiation regions C1, C2, and C3 can have a smaller size as the irradiation pattern including the non-irradiation region is smaller. Therefore, the relation in size of the non-irradiation region C1<the non-irradiation region C2<the non-irradiation region C3 may hold. Therefore, the smallest non-irradiation region C1 can be formed in the smallest irradiation pattern P.sub.Hot (with the maximum light intensity). This means that the irradiation pattern P.sub.Hot can allow a wider region to be irradiated with light more brighter when compared with the case where a smallest non-irradiation region C1 is formed in the irradiation patterns P.sub.Mid and P.sub.Wide other than the smallest irradiation pattern P.sub.Hot. Furthermore, since the smallest non-irradiation region C1 is formed in the smallest irradiation pattern P.sub.Hot with the maximum light intensity, the bright/dark ratio near the contour of the non-irradiation region C can become relatively high (see
(269) The non-irradiation regions C1, C2, and C3 formed in the respective irradiation patterns P.sub.Hot, P.sub.Mid, and P.sub.Wide can have a similarity shape. Even when the non-irradiation regions C1, C2, and C3 formed by the respective irradiation patterns P.sub.Hot, P.sub.Mid, and P.sub.Wide are displaced from one another, the area of the resulting non-irradiation region C (see the hatched region in
(270) The high-beam light distribution pattern P.sub.Hi shown in
(271) The light intensity distributions can be formed in the respective scanning areas A.sub.Hot, A.sub.Mid, and A.sub.Wide by the following procedures.
(272) The wide-zone optical deflector 201.sub.Wide can draw a first two-dimensional image on the wide-zone scanning area A.sub.Wide (see
(273) The middle-zone optical deflector 201.sub.Mid can draw a second two-dimensional image on the middle-zone scanning area A.sub.Mid (see
(274) The hot-zone optical deflector 201.sub.Hot can draw a third two-dimensional image on the hot-zone scanning area A.sub.Hot (see
(275) It should be appreciated that the first to third light intensity distributions can be formed in the respective scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot so as to include the non-irradiation region corresponding to the non-irradiation regions C1, C2, and C3 by overlaying the non-irradiation regions C1, C2, and C3 to form the non-irradiation region.
(276) As described above, the light intensity distributions formed in the respective scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot can be projected forward by the projection lens assembly 20, to thereby form the high-beam light distribution pattern P.sub.Hi on a virtual vertical screen as shown in
(277) As described above, this reference example can provide a vehicle lighting fixture configured to form a predetermined light distribution pattern (for example, a high-beam light distribution pattern) by overlaying a plurality of irradiation patterns P.sub.Hot, P.sub.Mid, and P.sub.Wide including the respective non-irradiation regions C1, C2, and C3. Thus, even when the non-irradiation regions C1, C2, and C3 formed in the respective irradiation patterns P.sub.Hot, P.sub.Mid, and P.sub.Wide are displaced from one another (as shown in
(278) This can be achieved by designing the non-irradiation regions C1, C2, and C3 to have respective different sizes to be formed in the respective irradiation patterns P.sub.Hot, P.sub.Mid, and P.sub.Wide.
(279) It should be appreciated that two vehicle lighting fixtures 300 can be used to form a single high-beam light distribution pattern P.sub.Hi (illustrated in
(280)
(281) The high-beam light distribution patterns PL.sub.Hi and PR.sub.Hi, as illustrated in
(282) The non-irradiation region C (non-irradiation regions C1, C2, and C3) and non-irradiation region C4 can have respectively different sizes as illustrated in
(283) Next, a description will now be given of a case where, when at least one of excitation light sources (for example, wide-zone, middle-zone, and hot-zone excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot) and optical deflectors (for example, wide-zone, middle-zone, and hot-zone optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot) is failed, the luminance distribution assigned to the failed optical deflector or the optical deflector corresponding to the failed excitation light source before the detection of such a failure can be compensated with.
(284)
(285) As illustrated in
(286) Hereinbelow, a description will be given of the different point of this reference example from the previously described reference example (vehicle lighting fixture 300 or 400), and the same or similar components of this reference example as those in the previously described reference example will be denoted by the same reference numerals and a description thereof will be omitted as appropriate.
(287) The wide-zone optical unit 502.sub.Wide can include a wide-zone excitation light source 12.sub.Wide, a wide-zone optical deflector 201.sub.Wide a wide-zone driver/controller 508.sub.Wide for driving the wide-zone optical deflector and outputting a synchronous signal and the like for control, and a wide-zone current-strengthened laser driver 510.sub.Wide. Similarly, the middle-zone optical unit 502.sub.Mid can include a middle-zone excitation light source 12.sub.Mid, a middle-zone optical deflector 201.sub.Mid, a middle-zone driver/controller 508.sub.Mid for driving the middle-zone optical deflector and outputting a synchronous signal and the like for control, and a middle-zone current-strengthened laser driver 510.sub.Mid. Furthermore, similarly, the hot-zone optical unit 502.sub.Hot can include a hot-zone excitation light source 12.sub.Hot, a hot-zone optical deflector 201.sub.Hot, a hot-zone driver/controller 508.sub.Hot for driving the hot-zone optical deflector and outputting a synchronous signal and the like for control, and a hot-zone current-strengthened laser driver 510.sub.Hot.
(288) The storage device 506 can store various pieces of information, including basic light distribution data, divided light distribution data (wide-zone divided light distribution data, middle-zone divided light distribution data, and hot-zone divided light distribution data), voltage-swing angle characteristics (for example, those illustrated in
(289) As illustrated in
(290) Here, the basic light distribution data can be referred to as a basic luminance distribution or a basic light distribution, and can be represented by a luminance image formed by a plurality of pixels with a plurality of luminance values in a plurality of bits. For example, such a luminance image can be formed by 640 pixels by 360 pixels as schematically illustrated in
(291) Furthermore, the divided light distribution data can be referred to as a divided luminance distribution or a divided light distribution, and can be represented by a luminance image (for example, those illustrated in
(292) As illustrated in
(293) The voltage-swing angle characteristics can be prepared for the respective optical deflectors. The current-brightness characteristics can be prepared for the respective excitation light sources.
(294) The imaging engine CPU 504 can control the three excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot, and the three optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot so that the luminance distributions formed in the respective three scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot (see
(295) The imaging engine CPU 504 can output a drive signal(s) to the respective driver/controller 508.sub.Wide, 508.sub.Mid, and 508.sub.Hot on the basis of the respective pieces of divided light distribution data (and respective pieces of swing angle data and voltage-swing angle characteristics) so as to control them. This control can be performed to apply respective drive voltages to the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot so that the vertical width and the horizontal width of the luminance distribution formed in each of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot become those of luminance distribution (light intensity distribution) represented by the divided light distribution data.
(296) Furthermore, the imaging engine CPU 504 can output a drive signal(s) to the respective current-strengthened laser driver 510.sub.Wide, 510.sub.Mid, and 510.sub.Hot on the basis of the respective pieces of divided light distribution data (and respective pieces of current-brightness characteristics) so as to control them. This control can be performed to apply respective drive currents to the respective excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot so that the luminance distribution formed in each of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot becomes the luminance distribution (light intensity distribution) represented by the divided light distribution data.
(297) Then, the respective driver/controllers 508.sub.Wide, 508.sub.Mid, and 508.sub.Hot can apply the drive voltages to the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot according to the control (drive signal) by the imaging engine CPU 504, with the drive voltages having been adjusted such that the vertical width and the horizontal width of the luminance distribution formed in each of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot become those of luminance distribution represented by the divided light distribution data. Here, the drive voltage can be a drive voltage for resonantly driving the optical deflector and/or a drive voltage for nonresonantly driving the optical deflector, for example, those illustrated in
(298) Furthermore, the respective current-strengthened laser drivers 510.sub.Wide, 510.sub.Mid, and 510.sub.Hot can apply the drive currents to the respective excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot according to the control (drive signal) by the imaging engine CPU 504, with the drive currents having been adjusted such that the luminance distribution formed in each of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot becomes the luminance distribution represented by the divided light distribution data. Here, the drive current can be that illustrated in
(299) As described above, the imaging engine CPU 504 can function as a control unit for controlling the three excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot, and the three optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot so that the luminance distributions (wide-zone, middle-zone, and hot-zone divided luminance distributions) assigned to the three optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot can be formed in the wavelength converting member 18. Note that the imaging engine CPU 504 can be configured to execute a predetermined program to achieve the function of the control unit.
(300)
(301) As illustrated in
(302) In this case, a plurality of sensors can be attached to a vehicle body in which the vehicle lighting fixture 500 is installed. According to at least one signal from the plurality of sensors, the driving situation at that time can be recognized. For example, on the basis of a signal (signal indicative of own vehicle position information, map information, etc.) from a car navigation system 512 (see
(303) Next, the basic light distribution data suitable for and corresponding to the recognized driving situation is calculated or read out from the storage device 506 (Step S104).
(304) If an imaging device (not illustrated) such as a CCD electrically connected to the imaging engine CPU 504 captures an image containing an irradiation-prohibitive object such as a preceding vehicle, an oncoming vehicle, and a pedestrian, then a basic distribution pattern including a non-irradiation region where the luminance value is zero (0) is generated. In this case the non-irradiation region corresponds to the region where the irradiation-prohibitive object is present. For example, as illustrated in
(305) Next, the process of dividing optimum light distribution is performed (Step S106).
(306)
(307) As illustrated in
(308)
(309) First, the process of dividing optimum light distribution when a mode is transferred to a normal driving mode (step S106) determines the maximum light intensity and the scanning areas (the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot, i.e. swing angle data) assigned to the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot (see
(310) The maximum light intensity means the maximum light intensity at each of the scanning areas assigned to the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot, and examples thereof may include approx. 2,500 cd, approx. 4,500 cd, approx. 8,000 cd, and approx. 25,000 cd (four points on the vertical axis in
(311) The scanning areas (swing angle data) assigned to the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot can be determined by the angles (angular ranges) between intersections of the horizontal line passing through the determined maximum light intensity and the graph showing the OBJECT in
(312) For example, the scanning area (or the hot-zone swing angle data) assigned to the optical deflector 201.sub.Hot can be determined by the angles (angular range of 5.0) between intersections of the horizontal line passing through the determined maximum light intensity (approximately 25,000 cd) and the graph (the first target luminance distribution) showing the OBJECT in
(313) The respective scanning areas in
(314) Next, an optimization process is performed. Specifically, the process can include optimization of the determined scanning areas assigned to the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot to contain the graph of OBJECT (first target luminance distribution) in
(315) Next, the basic light distribution data calculated or read-out in step S104 can be divided into the three wide-zone divided light distribution data, middle-zone divided light distribution data, and hot-zone divided light distribution data as illustrated in
(316) Specifically, first, a divided light distribution 1 (for example, wide-zone divided light distribution data, see the graph of AREA1 in
(317) Next, a divided light distribution 2 (for example, middle-zone divided light distribution data, see the graph of AREA2 in
(318) Furthermore, a divided light distribution 3 (for example, middle-zone divided light distribution data, see the graph of AREA3 in
(319) Furthermore, a divided light distribution 4 (for example, hot-zone divided light distribution data, see the graph of AREA4 in
(320) In this manner, the divided light distributions (divided luminance distributions or wide-zone divided light distribution data, middle-zone divided light distribution data, and hot-zone divided light distribution data) and swing angle data (wide-zone swing angle data, middle-zone swing angle data, and hot-zone swing angle data) assigned to the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot can be generated.
(321) The first target luminance distribution can be configured to have the maximum luminance at or near its center and gradually decreased luminance toward both sides (vertically and horizontally) as in the graph of OBJECT in
(322) Incidentally,
(323) Furthermore, in place of the above-described process of dividing optimum light distribution (step S106), the divided light distribution data (wide-zone divided light distribution data, middle-zone divided light distribution data, and hot-zone divided light distribution data) and swing angle data (wide-zone swing angle data, middle-zone swing angle data, and hot-zone swing angle data) in association therewith that are suitable for and correspond to a driving situation identified in step S102 can be read out from the storage device 506. In this case, the process of step S104 can be omitted.
(324) Next, the voltage-swing angle characteristics of the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot can be read out from the storage device 506. If the voltage-swing angle characteristics of the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot temporarily vary, the voltage-swing angle characteristics of the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot may be appropriately updated.
(325) Next, the imaging engine CPU 504 can control the three excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot and the three optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot so that the luminance distributions formed in the respective scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot (see
(326) The imaging engine CPU 504 can output a drive signal(s) to the respective driver/controllers 508.sub.Wide, 508.sub.Mid, and 508.sub.Hot on the basis of the respective pieces of divided light distribution data (and respective pieces of swing angle data and voltage-swing angle characteristics) so as to control them. This control can be performed to apply respective drive voltages to the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot so that the vertical width and the horizontal width of the luminance distribution formed in each of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot become those of luminance distribution (light intensity distribution) represented by the divided light distribution data.
(327) At the same time, the imaging engine CPU 504 can output a drive signal(s) to the respective current-strengthened laser drivers 510.sub.Wide, 510.sub.Mid, and 510.sub.Hot on the basis of the respective pieces of divided light distribution data (and respective pieces of current-brightness characteristics) so as to control them. This control can be performed to apply respective drive currents to the respective excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot so that the luminance distribution formed in each of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot becomes the luminance distribution (light intensity distribution) represented by the divided light distribution data.
(328) Then, the respective driver/controllers 508.sub.Wide, 508.sub.Mid, and 508.sub.Hot can apply the drive voltages to the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot according to the control (drive signal) by the imaging engine CPU 504, with the drive voltages having been adjusted such that the vertical width and the horizontal width of the luminance distribution formed in each of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot become those of luminance distribution represented by the divided light distribution data. Here, the drive voltage can be a drive voltage for resonantly driving the optical deflector and/or a drive voltage for nonresonantly driving the optical deflector, for example, those illustrated in
(329) In synchronization with this, the respective current-strengthened laser drivers 510.sub.Wide, 510.sub.Mid, and 510.sub.Hot can apply the drive currents to the respective excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot according to the control (drive signal) by the imaging engine CPU 504, with the drive currents having been adjusted such that the luminance distribution formed in each of the scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot becomes the luminance distribution represented by the divided light distribution data. Here, the drive current can be one illustrated in
(330) As described above, when the process of dividing optimum light distribution when a mode is transferred to a normal driving mode (S106) is performed, the three excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot and the three optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot can be controlled by the imaging engine CPU 504 to form the luminance distribution (wide-zone divided luminance distribution, middle-zone divided luminance distribution, and hot-zone divided luminance distribution) configured to be coincident with the first target luminance distribution or the luminance distributions assigned to the three excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot.
(331) Accordingly, since the three excitation light sources 12.sub.Wide, 12.sub.Mid, and 12.sub.Hot and the three optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot can be controlled in synchronization with one another, the three optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot can draw two-dimensional images on the three scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot by the excitation light rays two-dimensionally scanning in the horizontal and vertical directions by the mirror parts 202 of the respective optical deflectors 201.sub.Wide, 201.sub.Mid, and 201.sub.Hot. As a result, the luminance distributions coincident with or substantially coincident with the first target luminance distribution can be formed on the wavelength converting member 18.
(332) The luminance distributions formed on the wavelength converting member 18 can be projected forward by the projection lens assembly 20 to form a predetermined light distribution pattern corresponding to the luminance distributions on a virtual vertical screen.
(333) Next, a description will be given of a process of changing luminance distributions assigned to a plurality of optical deflectors (for example, three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3)) as an exemplary embodiment.
(334)
(335) As illustrated in
(336) Hereinafter, a description will be given of a different point of this exemplary embodiment from the vehicle lighting fixture 500 of
(337) As illustrated in
(338) The first optical unit 502.sub.(1) can include a first excitation light source 12.sub.(1), a first optical deflector 201.sub.(1), a first driver/controller 508.sub.(1) for driving the first optical deflector and outputting a synchronous signal and the like for control, and a first current-strengthened laser driver 510.sub.(1). Similarly, the second optical unit 502.sub.(2) can include a second excitation light source 12.sub.(2), a second optical deflector 201.sub.(2), a second driver/controller 508.sub.(2) for driving the second optical deflector and outputting a synchronous signal and the like for control, and a second current-strengthened laser driver 510.sub.(2). Similarly, the third optical unit 502.sub.(3) can include a third excitation light source 12.sub.(3), a third optical deflector 201.sub.(3), a third driver/controller 508.sub.(3), for driving the third optical deflector and outputting a synchronous signal and the like for control, and a third current-strengthened laser driver 510.sub.(3).
(339) The imaging engine CPU 504 can execute a predefined program to function as a changing unit for changing the luminance distributions assigned to the respective three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3). The imaging engine CPU 504 can change the luminance distributions assigned to the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) at a predetermined timing. For example, the timing may be a timing when a not-illustrated headlamp switch is turned off or a timing when the headlamp switch is turned on. For example, assume that the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) can form respectively different sized luminance distributions. In this case, the imaging engine CPU 504 can change the luminance distributions different in size from those assigned to the optical deflectors before the change. This can be achieved by, for example, storing a mode A (or data representing the mode A), a mode B (or data representing the mode B), or a mode C (or data representing the mode C) in the assigned scanning area register 504b built in the imaging engine CPU 504, as illustrated in
(340) The mode A (or data representing the mode A) can indicate that the luminance distribution and the swing angle data assigned to the first optical unit 502.sub.(1) (the first optical deflector 201.sub.(1)) are a wide-zone luminance distribution (wide-zone divided light distribution data) and wide-zone swing angle data, that the luminance distribution and the swing angle data assigned to the second optical unit 502.sub.(2) (the second optical deflector 201.sub.(2)) are a middle-zone luminance distribution (middle-zone divided light distribution data) and middle-zone swing angle data, and that the luminance distribution and the swing angle data assigned to the third optical unit 502.sub.(3) (the third optical deflector 201.sub.(3)) are a hot-zone luminance distribution (hot-zone divided light distribution data) and hot-zone swing angle data, as illustrated in
(341) The mode B (or data representing the mode B) can indicate that the luminance distribution and the swing angle data assigned to the first optical unit 502.sub.(1) (the first optical deflector 201.sub.(1)) are the hot-zone luminance distribution (hot-zone divided light distribution data) and the hot-zone swing angle data, that the luminance distribution and the swing angle data assigned to the second optical unit 502.sub.(2) (the second optical deflector 201.sub.(2)) are the wide-zone luminance distribution (wide-zone divided light distribution data) and the wide-zone swing angle data, and that the luminance distribution and the swing angle data assigned to the third optical unit 502.sub.(3) (the third optical deflector 201.sub.(3)) are the middle-zone luminance distribution (middle-zone divided light distribution data) and the middle-zone swing angle data, as illustrated in
(342) The mode C (or data representing the mode C) can indicate that the luminance distribution and the swing angle data assigned to the first optical unit 502.sub.(1) (the first optical deflector 201.sub.(1)) are the middle-zone luminance distribution (middle-zone divided light distribution data) and the middle-zone swing angle data, that the luminance distribution and the swing angle data assigned to the second optical unit 502.sub.(2) (the second optical deflector 201.sub.(2)) are the hot-zone luminance distribution (hot-zone divided light distribution data) and the hot-zone swing angle data, and that the luminance distribution and the swing angle data assigned to the third optical unit 502.sub.(3) (the third optical deflector 201.sub.(3)) are the wide-zone luminance distribution (wide-zone divided light distribution data) and the wide-zone swing angle data, as illustrated in
(343) A description will now be given of an operation example of the vehicle lighting fixture 500A with the above-described configuration, with reference to
(344) The following processing can be achieved by the imaging engine CPU 504 that reads out a predefined program from the storage device 506 in a RAM (not illustrated) etc., and executes the program.
(345) A description will be given of the operation example when the mode A (or data representing the mode A) has been previously stored in the assigned scanning area register 504b as a default value (see
Operation Example of Mode A
(346) As shown in
(347) Next, the basic light distribution data suitable for and corresponding to the recognized driving situation is calculated or read out from the storage device 506 (Step S104).
(348) Next, the process of dividing optimum light distribution is performed (Step S106). This process can generate divided light distribution data (divided luminance distribution or wide-zone divided light distribution data, middle-zone divided light distribution data, and hot-zone divided light distribution data) and swing angle data (wide-zone swing angle data, middle-zone swing angle data, and hot-zone swing angle data) assigned to the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3).
(349) Incidentally, in place of the process of dividing optimum light distribution (step S106), the divided light distribution data (wide-zone divided light distribution data, middle-zone divided light distribution data, and hot-zone divided light distribution data) and swing angle data (wide-zone swing angle data, middle-zone swing angle data, and hot-zone swing angle data) in association with the divided light distribution data suitable for and corresponding to the recognized driving situation in step S102 can be stored in advance in and read out from the storage device 506. In this case, the process of step S104 can be omitted.
(350) Next, the imaging engine CPU 504 refers to the assigned scanning region register 504b (the mode A stored in this register 504b) (step S107).
(351) Next, the imaging engine CPU 504 reads out the voltage-swing angle characteristics of the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) from the storage device 506 (step S108).
(352) Then, the imaging engine CPU 504 can control the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3) and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) to form the luminance distributions (see
(353) The imaging engine CPU 504 can output a drive signal to the first driver/controller 508.sub.(1) on the basis of the wide-zone divided light distribution data (and wide-zone swing angle data and voltage-swing angle characteristics) so as to control it. This control can be performed to apply a drive voltage to the first optical deflector 201.sub.(1), so that the vertical width and the horizontal width of the luminance distribution formed in the wide-zone scanning area A.sub.Wide become those of luminance distribution (light intensity distribution) represented by the wide-zone divided light distribution data as illustrated in
(354) Furthermore, the imaging engine CPU 504 can output a drive signal to the first current-strengthened laser driver 510.sub.(1) on the basis of the wide-zone divided light distribution data (and current-brightness characteristics) so as to control it. This control can be performed to apply a drive current to the first excitation light source 12.sub.(1) so that the luminance distribution formed in the wide-zone scanning area A.sub.Wide becomes the luminance distribution (light intensity distribution) represented by the wide-zone divided light distribution data.
(355) Then, the first driver/controller 508.sub.(1) can apply the drive voltage to the first optical deflector 201.sub.(1) according to the control (drive signal) by the imaging engine CPU 504, with the drive voltage having been adjusted such that the vertical width and the horizontal width of the luminance distribution formed in the wide-zone scanning area A.sub.Wide become those of luminance distribution represented by the wide-zone divided light distribution data. Here, the drive voltage can be a drive voltage for resonantly driving the optical deflector and/or a drive voltage for nonresonantly driving the optical deflector, for example, those illustrated in
(356) Furthermore, in synchronization with this control, the first current-strengthened laser driver 510.sub.(1) can apply the drive current to the first excitation light source 12.sub.(1) according to the control (drive signal) by the imaging engine CPU 504, with the drive current having been adjusted such that the luminance distribution formed in the wide-zone scanning area A.sub.Wide becomes the luminance distribution represented by the wide-zone divided light distribution data. Here, the drive current can be one illustrated in
(357) Similarly, the imaging engine CPU 504 can output a drive signal to the second driver/controller 508.sub.(2) on the basis of the middle-zone divided light distribution data (and middle-zone swing angle data and voltage-swing angle characteristics) so as to control it. This control can be performed to apply a drive voltage to the second optical deflector 201.sub.(2) so that the vertical width and the horizontal width of the luminance distribution formed in the middle-zone scanning area A.sub.Mid become those of luminance distribution (light intensity distribution) represented by the middle-zone divided light distribution data as illustrated in
(358) Furthermore, the imaging engine CPU 504 can output a drive signal to the second current-strengthened laser driver 510.sub.(2) on the basis of the middle-zone divided light distribution data (and current-brightness characteristics) so as to control it. This control can be performed to apply a drive current to the second excitation light source 12.sub.(2) so that the luminance distribution formed in the middle-zone scanning area A.sub.Mid becomes the luminance distribution (light intensity distribution) represented by the middle-zone divided light distribution data.
(359) Then, the second driver/controller 508.sub.(2) can apply the drive voltage to the second optical deflector 201.sub.(2) according to the control (drive signal) by the imaging engine CPU 504, with the drive voltage having been adjusted such that the vertical width and the horizontal width of the luminance distribution formed in the middle-zone scanning area A.sub.Mid become those of luminance distribution represented by the middle-zone divided light distribution data. Here, the drive voltage can be a drive voltage for resonantly driving the optical deflector and/or a drive voltage for nonresonantly driving the optical deflector, for example, those illustrated in
(360) Furthermore, in synchronization with this control, the second current-strengthened laser driver 510.sub.(2) can apply the drive current to the second excitation light source 12.sub.(2) according to the control (drive signal) by the imaging engine CPU 504, with the drive current having been adjusted such that the luminance distribution formed in the middle-zone scanning area A.sub.Mid becomes the luminance distribution represented by the middle-zone divided light distribution data. Here, the drive current can be one illustrated in
(361) Similarly, the imaging engine CPU 504 can output a drive signal to the third driver/controller 508.sub.(3) on the basis of the hot-zone divided light distribution data (and hot-zone swing angle data and voltage-swing angle characteristics) so as to control it. This control can be performed to apply a drive voltage to the third optical deflector 201.sub.(3) so that the vertical width and the horizontal width of the luminance distribution formed in the hot-zone scanning area A.sub.Hot become those of luminance distribution (light intensity distribution) represented by the hot-zone divided light distribution data as illustrated in
(362) Furthermore, the imaging engine CPU 504 can output a drive signal to the third current-strengthened laser driver 510.sub.(3) on the basis of the hot-zone divided light distribution data (and current-brightness characteristics) so as to control it. This control can be performed to apply a drive current to the third excitation light source 12.sub.(3) so that the luminance distribution formed in the hot-zone scanning area A.sub.Hot becomes the luminance distribution (light intensity distribution) represented by the hot-zone divided light distribution data.
(363) Then, the third driver/controller 508.sub.(3) can apply the drive voltage to the third optical deflector 201.sub.(3) according to the control (drive signal) by the imaging engine CPU 504, with the drive voltage having been adjusted such that the vertical width and the horizontal width of the luminance distribution formed in the hot-zone scanning area A.sub.Hot become those of luminance distribution represented by the hot-zone divided light distribution data. Here, the drive voltage can be a drive voltage for resonantly driving the optical deflector and/or a drive voltage for nonresonantly driving the optical deflector, for example, those illustrated in
(364) Furthermore, in synchronization with this control, the third current-strengthened laser driver 510.sub.(3) can apply the drive current to the third excitation light source 12.sub.(3) according to the control (drive signal) by the imaging engine CPU 504, with the drive current having been adjusted such that the luminance distribution formed in the hot-zone scanning area A.sub.Hot becomes the luminance distribution represented by the hot-zone divided light distribution data. Here, the drive current can be one illustrated in
(365) As described above, the control unit, or the imaging engine CPU 504, can control the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3), and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) to form the luminance distributions (see
(366) Accordingly, since the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3) and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) can be controlled in synchronization with one another, the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) can draw two-dimensional images on the three scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot by the excitation light rays two-dimensionally scanning in the horizontal and vertical directions by the mirror parts 202 of the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3). As a result, the luminance distributions coincident with or substantially coincident with the first target luminance distribution can be formed on the wavelength converting member 18.
(367) The luminance distributions formed on the wavelength converting member 18 can be projected forward by the projection lens assembly 20 to form a predetermined light distribution pattern corresponding to the luminance distributions on a virtual vertical screen.
(368) The above-mentioned steps S102 to S110 are repeatedly performed until the headlamp switch (not illustrated) is turned off (Yes in step S112).
(369) When the headlamp switch is turned off (Yes in step S112), the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3) and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) are stopped (step S114). In other words, the imaging engine CPU 504 can control to stop the driver/controllers 508.sub.(1), 508.sub.(2), and 508.sub.(3) and the current-strengthened laser drivers 510.sub.(1), 510.sub.(2), and 510.sub.(3).
(370) Then, the content of the assigned scanning region register 504b is changed (step S116). Since the mode A (or data representing the mode A) has been stored in the assigned scanning region register 504b, the content (mode A) of the assigned scanning region register 504b is changed to the mode B (or data representing the mode B).
(371) As described above, the imaging engine CPU 504 can change the mode A (or data representing the mode A) to the mode B (or data representing the mode B) in the assigned scanning region register 504b at the timing when the headlamp switch is turned off. Thus, the luminance distributions assigned to the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) can be changed such that the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) are assigned to luminance distributions different in size from those assigned to the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) before the mode change. For example, the luminance distribution assigned to the first optical deflector 201.sub.(1) is changed from the wide-zone divided luminance distribution to the hot-zone divided luminance distribution. Furthermore, the luminance distribution assigned to the second optical deflector 201.sub.(2) is changed from the middle-zone divided luminance distribution to the wide-zone divided luminance distribution, and the luminance distribution assigned to the third optical deflector 201.sub.(3) is changed from the hot-zone divided luminance distribution to the middle-zone divided luminance distribution.
(372) In this manner, the operation in the mode A is terminated.
(373) Next, a description will be given of the operation example when the mode B (or data representing the mode B) is stored in the assigned scanning area register 504b as a result of the aforementioned changing process (see
Operation Example of Mode B
(374) When the headlamp switch (not illustrated) is turned on (Yes in step S101), the process from S102 to S116 is performed.
(375) Specifically, the imaging engine CPU 504 can control the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3) and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) to form the luminance distributions assigned to the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) indicated by the assigned scanning region register 504b (the mode B stored in this register 504b) that has been referred to in step S107. Specifically, the control can be performed to form the hot-zone luminance distribution assigned to the first optical deflector 201.sub.(1), the wide-zone luminance distribution assigned to the second optical deflector 201.sub.(2), and the middle-zone luminance distribution assigned to the third optical deflector 201.sub.(3), on the wavelength converting member 18.
(376) The imaging engine CPU 504 can output a drive signal to the first driver/controller 508.sub.(1) on the basis of the hot-zone divided light distribution data (and hot-zone swing angle data and voltage-swing angle characteristics) so as to control it. This control can be performed to apply a drive voltage to the first optical deflector 201.sub.(1) so that the vertical width and the horizontal width of the luminance distribution formed in the hot-zone scanning area A.sub.Hot become those of luminance distribution (light intensity distribution) represented by the hot-zone divided light distribution data as illustrated in
(377) Furthermore, the imaging engine CPU 504 can output a drive signal to the first current-strengthened laser driver 510.sub.(1) on the basis of the hot-zone divided light distribution data (and current-brightness characteristics) so as to control it. This control can be performed to apply a drive current to the first excitation light source 12.sub.(1) so that the luminance distribution formed in the hot-zone scanning area A.sub.Hot becomes the luminance distribution (light intensity distribution) represented by the hot-zone divided light distribution data.
(378) Then, the first driver/controller 508.sub.(1) can apply the drive voltage to the first optical deflector 201.sub.(1) according to the control (drive signal) by the imaging engine CPU 504, with the drive voltage having been adjusted such that the vertical width and the horizontal width of the luminance distribution formed in the hot-zone scanning area A.sub.Hot become those of luminance distribution represented by the hot-zone divided light distribution data. Here, the drive voltage can be a drive voltage for resonantly driving the optical deflector and/or a drive voltage for nonresonantly driving the optical deflector, for example, those illustrated in
(379) Furthermore, in synchronization with this control, the first current-strengthened laser driver 510.sub.(1) can apply the drive current to the first excitation light source 12.sub.(1) according to the control (drive signal) by the imaging engine CPU 504, with the drive current having been adjusted such that the luminance distribution formed in the hot-zone scanning area A.sub.Hot becomes the luminance distribution represented by the hot-zone divided light distribution data. Here, the drive current can be one illustrated in
(380) Similarly, the imaging engine CPU 504 can output a drive signal to the second driver/controller 508.sub.(2) on the basis of the wide-zone divided light distribution data (and wide-zone swing angle data and voltage-swing angle characteristics) so as to control it. This control can be performed to apply a drive voltage to the second optical deflector 201.sub.(2) so that the vertical width and the horizontal width of the luminance distribution formed in the wide-zone scanning area A.sub.Wide become those of luminance distribution (light intensity distribution) represented by the wide-zone divided light distribution data as illustrated in
(381) Furthermore, the imaging engine CPU 504 can output a drive signal to the second current-strengthened laser driver 510.sub.(2) on the basis of the wide-zone divided light distribution data (and current-brightness characteristics) so as to control it. This control can be performed to apply a drive current to the second excitation light source 12.sub.(2) so that the luminance distribution formed in the wide-zone scanning area A.sub.Wide becomes the luminance distribution (light intensity distribution) represented by the wide-zone divided light distribution data.
(382) Then, the second driver/controller 508.sub.(2) can apply the drive voltage to the second optical deflector 201.sub.(2) according to the control (drive signal) by the imaging engine CPU 504, with the drive voltage having been adjusted such that the vertical width and the horizontal width of the luminance distribution formed in the wide-zone scanning area A.sub.Wide become those of luminance distribution represented by the wide-zone divided light distribution data. Here, the drive voltage can be a drive voltage for resonantly driving the optical deflector and/or a drive voltage for nonresonantly driving the optical deflector, for example, those illustrated in
(383) Furthermore, in synchronization with this control, the second current-strengthened laser driver 510.sub.(2) can apply the drive current to the second excitation light source 12.sub.(2) according to the control (drive signal) by the imaging engine CPU 504, with the drive current having been adjusted such that the luminance distribution formed in the wide-zone scanning area A.sub.Wide becomes the luminance distribution represented by the wide-zone divided light distribution data. Here, the drive current can be one illustrated in
(384) Similarly, the imaging engine CPU 504 can output a drive signal to the third driver/controller 508.sub.(3) on the basis of the middle-zone divided light distribution data (and middle-zone swing angle data and voltage-swing angle characteristics) so as to control it. This control can be performed to apply a drive voltage to the third optical deflector 201.sub.(3) so that the vertical width and the horizontal width of the luminance distribution formed in the middle-zone scanning area A.sub.Mid become those of luminance distribution (light intensity distribution) represented by the middle-zone divided light distribution data as illustrated in
(385) Furthermore, the imaging engine CPU 504 can output a drive signal to the third current-strengthened laser driver 510.sub.(3) on the basis of the middle-zone divided light distribution data (and current-brightness characteristics) so as to control it. This control can be performed to apply a drive current to the third excitation light source 12.sub.(3) so that the luminance distribution formed in the middle-zone scanning area A.sub.Mid becomes the luminance distribution (light intensity distribution) represented by the middle-zone divided light distribution data.
(386) Then, the third driver/controller 508.sub.(3) can apply the drive voltage to the third optical deflector 201.sub.(3) according to the control (drive signal) by the imaging engine CPU 504, with the drive voltage having been adjusted such that the vertical width and the horizontal width of the luminance distribution formed in the middle-zone scanning area A.sub.Mid become those of luminance distribution represented by the middle-zone divided light distribution data. Here, the drive voltage can be a drive voltage for resonantly driving the optical deflector and/or a drive voltage for nonresonantly driving the optical deflector, for example, those illustrated in
(387) Furthermore, in synchronization with this control, the third current-strengthened laser driver 510.sub.(3) can apply the drive current to the third excitation light source 12.sub.(3) according to the control (drive signal) by the imaging engine CPU 504, with the drive current having been adjusted such that the luminance distribution formed in the middle-zone scanning area A.sub.Mid becomes the luminance distribution represented by the middle-zone divided light distribution data. Here, the drive current can be one illustrated in
(388) As described above, the control unit, or the imaging engine CPU 504, can control the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3) and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) to form the luminance distributions (see
(389) Accordingly, since the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3) and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) can be controlled in synchronization with one another, the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) can draw two-dimensional images on the three scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot by the excitation light rays two-dimensionally scanning in the horizontal and vertical directions by the mirror parts 202 of the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3). As a result, the luminance distributions coincident with or substantially coincident with the first target luminance distribution can be formed on the wavelength converting member 18.
(390) The luminance distributions formed on the wavelength converting member 18 can be projected forward by the projection lens assembly 20 to form a predetermined light distribution pattern corresponding to the luminance distributions on a virtual vertical screen.
(391) The above-mentioned steps S102 to S110 are repeatedly performed until the headlamp switch (not illustrated) is turned off (Yes in step S112).
(392) When the headlamp switch is turned off (Yes in step S112), the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3) and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) are stopped (step S114). In other words, the imaging engine CPU 504 can control to stop the driver/controllers 508.sub.(1), 508.sub.(2), and 508.sub.(3) and the current-strengthened laser drivers 510.sub.(1), 510.sub.(2), and 510.sub.(3).
(393) Then, the content of the assigned scanning region register 504b is changed (step S116). Since the mode B (or data representing the mode B) has been stored in the assigned scanning region register 504b, the content (mode B) of the assigned scanning region register 504b is changed to the mode C (or data representing the mode C).
(394) As described above, the imaging engine CPU 504 can change the mode B (or data representing the mode B) to the mode C (or data representing the mode C) in the assigned scanning region register 504b at the timing when the headlamp switch is turned off. Thus, the luminance distributions assigned to the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) can be changed such that the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) are assigned to luminance distributions different in size from those assigned to the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) before the mode change. For example, the luminance distribution assigned to the first optical deflector 201.sub.(1) is changed from the hot-zone divided luminance distribution to the middle-zone divided luminance distribution. Furthermore, the luminance distribution assigned to the second optical deflector 201.sub.(2) is changed from the wide-zone divided luminance distribution to the hot-zone divided luminance distribution, and the luminance distribution assigned to the third optical deflector 201.sub.(3) is changed from the middle-zone divided luminance distribution to the wide-zone divided luminance distribution.
(395) In this manner, the operation in the mode B is terminated.
(396) Next, a description will be given of the operation example when the mode C (or data representing the mode C) is stored in the assigned scanning area register 504b as a result of the aforementioned changing process (see
Operation Example of Mode C
(397) When the headlamp switch (not illustrated) is turned on (Yes in step S101), the process from S102 to S116 is performed.
(398) Specifically, the imaging engine CPU 504 can control the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3) and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) to form the luminance distributions (see
(399) The imaging engine CPU 504 can output a drive signal to the first driver/controller 508.sub.(1) on the basis of the middle-zone divided light distribution data (and middle-zone swing angle data and voltage-swing angle characteristics) so as to control it. This control can be performed to apply a drive voltage to the first optical deflector 201.sub.(1) so that the vertical width and the horizontal width of the luminance distribution formed in the middle-zone scanning area A.sub.Mid become those of luminance distribution (light intensity distribution) represented by the middle-zone divided light distribution data as illustrated in
(400) Furthermore, the imaging engine CPU 504 can output a drive signal to the first current-strengthened laser driver 510.sub.(1) on the basis of the middle-zone divided light distribution data (and current-brightness characteristics) so as to control it. This control can be performed to apply a drive current to the first excitation light source 12.sub.(1) so that the luminance distribution formed in the middle-zone scanning area A.sub.Mid becomes the luminance distribution (light intensity distribution) represented by the middle-zone divided light distribution data.
(401) Then, the first driver/controller 508.sub.(1) can apply the drive voltage to the first optical deflector 201.sub.(1) according to the control (drive signal) by the imaging engine CPU 504, with the drive voltage having been adjusted such that the vertical width and the horizontal width of the luminance distribution formed in the middle-zone scanning area A.sub.Mid become those of luminance distribution represented by the middle-zone divided light distribution data. Here, the drive voltage can be a drive voltage for resonantly driving the optical deflector and/or a drive voltage for nonresonantly driving the optical deflector, for example, those illustrated in
(402) Furthermore, in synchronization with this control, the first current-strengthened laser driver 510.sub.(1) can apply the drive current to the first excitation light source 12.sub.(1) according to the control (drive signal) by the imaging engine CPU 504, with the drive current having been adjusted such that the luminance distribution formed in the middle-zone scanning area A.sub.Mid becomes the luminance distribution represented by the middle-zone divided light distribution data. Here, the drive current can be one illustrated in
(403) Similarly, the imaging engine CPU 504 can output a drive signal to the second driver/controller 508.sub.(2) on the basis of the hot-zone divided light distribution data (and hot-zone swing angle data and voltage-swing angle characteristics) so as to control it. This control can be performed to apply a drive voltage to the second optical deflector 201.sub.(2) so that the vertical width and the horizontal width of the luminance distribution formed in the hot-zone scanning area A.sub.Hot become those of luminance distribution (light intensity distribution) represented by the hot-zone divided light distribution data as illustrated in
(404) Furthermore, the imaging engine CPU 504 can output a drive signal to the second current-strengthened laser driver 510.sub.(2) on the basis of the hot-zone divided light distribution data (and current-brightness characteristics) so as to control it. This control can be performed to apply a drive current to the second excitation light source 12.sub.(2) so that the luminance distribution formed in the hot-zone scanning area A.sub.Hot becomes the luminance distribution (light intensity distribution) represented by the hot-zone divided light distribution data.
(405) Then, the second driver/controller 508.sub.(2) can apply the drive voltage to the second optical deflector 201.sub.(2) according to the control (drive signal) by the imaging engine CPU 504, with the drive voltage having been adjusted such that the vertical width and the horizontal width of the luminance distribution formed in the hot-zone scanning area A.sub.Hot become those of luminance distribution represented by the hot-zone divided light distribution data. Here, the drive voltage can be a drive voltage for resonantly driving the optical deflector and/or a drive voltage for nonresonantly driving the optical deflector, for example, those illustrated in
(406) Furthermore, in synchronization with this control, the second current-strengthened laser driver 510.sub.(2) can apply the drive current to the second excitation light source 12.sub.(2) according to the control (drive signal) by the imaging engine CPU 504, with the drive current having been adjusted such that the luminance distribution formed in the hot-zone scanning area A.sub.Hot becomes the luminance distribution represented by the hot-zone divided light distribution data. Here, the drive current can be one illustrated in
(407) Similarly, the imaging engine CPU 504 can output a drive signal to the third driver/controller 508.sub.(3) on the basis of the wide-zone divided light distribution data (and wide-zone swing angle data and voltage-swing angle characteristics) so as to control it. This control can be performed to apply a drive voltage to the third optical deflector 201.sub.(3) so that the vertical width and the horizontal width of the luminance distribution formed in the wide-zone scanning area A.sub.Wide become those of luminance distribution (light intensity distribution) represented by the wide-zone divided light distribution data as illustrated in
(408) Furthermore, the imaging engine CPU 504 can output a drive signal to the third current-strengthened laser driver 510.sub.(3) on the basis of the wide-zone divided light distribution data (and current-brightness characteristics) so as to control it. This control can be performed to apply a drive current to the third excitation light source 12.sub.(3) so that the luminance distribution formed in the wide-zone scanning area A.sub.Wide becomes the luminance distribution (light intensity distribution) represented by the wide-zone divided light distribution data.
(409) Then, the third driver/controller 508.sub.(3) can apply the drive voltage to the third optical deflector 201.sub.(3) according to the control (drive signal) by the imaging engine CPU 504, with the drive voltage having been adjusted such that the vertical width and the horizontal width of the luminance distribution formed in the wide-zone scanning area A.sub.Wide become those of luminance distribution represented by the wide-zone divided light distribution data. Here, the drive voltage can be a drive voltage for resonantly driving the optical deflector and/or a drive voltage for nonresonantly driving the optical deflector, for example, those illustrated in
(410) Furthermore, in synchronization with this control, the third current-strengthened laser driver 510.sub.(3) can apply the drive current to the third excitation light source 12.sub.(3) according to the control (drive signal) by the imaging engine CPU 504, with the drive current having been adjusted such that the luminance distribution formed in the wide-zone scanning area A.sub.Wide becomes the luminance distribution represented by the wide-zone divided light distribution data. Here, the drive current can be one illustrated in
(411) As described above, the control unit, or the imaging engine CPU 504, can control the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3) and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) to form the luminance distributions (see
(412) Accordingly, since the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3) and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) can be controlled in synchronization with one another, the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) can draw two-dimensional images on the three scanning areas A.sub.Wide, A.sub.Mid, and A.sub.Hot by the excitation light rays two-dimensionally scanning in the horizontal and vertical directions by the mirror parts 202 of the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3). As a result, the luminance distributions coincident with or substantially coincident with the first target luminance distribution can be formed on the wavelength converting member 18.
(413) The luminance distributions formed on the wavelength converting member 18 can be projected forward by the projection lens assembly 20 to form a predetermined light distribution pattern corresponding to the luminance distributions on a virtual vertical screen.
(414) The above-mentioned steps S102 to S110 are repeatedly performed until the headlamp switch (not illustrated) is turned off (Yes in step S112).
(415) When the headlamp switch is turned off (Yes in step S112), the three excitation light sources 12.sub.(1), 12.sub.(2), and 12.sub.(3) and the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) are stopped (step S114). In other words, the imaging engine CPU 504 can control to stop the driver/controllers 508.sub.(1), 508.sub.(2), and 508.sub.(3) and the current-strengthened laser drivers 510.sub.(1), 510.sub.(2), and 510.sub.(3).
(416) Then, the content of the assigned scanning region register 504b is changed (step S116). Since the mode C (or data representing the mode C) has been stored in the assigned scanning region register 504b, the content (mode C) of the assigned scanning region register 504b is changed to the mode A (or data representing the mode A).
(417) As described above, the imaging engine CPU 504 can change the mode C (or data representing the mode C) to the mode A (or data representing the mode A) in the assigned scanning region register 504b at the timing when the headlamp switch is turned off. Thus, the luminance distributions assigned to the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) can be changed such that the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) are assigned to luminance distributions different in size from those assigned to the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) before the mode change. For example, the luminance distribution assigned to the first optical deflector 201.sub.(1) is changed from the middle-zone divided luminance distribution to the wide-zone divided luminance distribution. Furthermore, the luminance distribution assigned to the second optical deflector 201.sub.(2) is changed from the hot-zone divided luminance distribution to the middle-zone divided luminance distribution, and the luminance distribution assigned to the third optical deflector 201.sub.(3) is changed from the wide-zone divided luminance distribution to the hot-zone divided luminance distribution.
(418) In this manner, the operation in the mode C is terminated.
(419) As described above, the imaging engine CPU 504 can change the content of the assigned scanning region register 504b from the mode A to the mode B, the mode C, the mode A, and so on (not limited to this sequence) at the timing when the headlamp switch (not illustrated) is turned off (or at any timing according to the desired specification). Thus, the imaging engine CPU 504 can control such that the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) are assigned to luminance distributions different in size from those assigned to the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) before the mode change.
(420) According to the above-described exemplary embodiment, the vehicle lighting fixture 500A utilizing the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) for the excitation light to scan can be miniaturized, and the parts number, which may become a cause for cost increase, can be decreased.
(421) The use of the single wavelength converting member 18 with respect to the three optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) can contribute to obtain the advantageous effects.
(422) Furthermore, according to the above-described exemplary embodiment, when compared with a case where the respective luminance distributions assigned to the plurality of optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) are not changed, the vehicle lighting fixture with the above-described configuration of the presently disclosed subject matter can extend the lives of the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3), by extension, can extend the life of the vehicle lighting fixture 500A itself.
(423) When a vehicle lighting fixture like the conventional one does not change the luminance distributions assigned to the respective optical deflectors, the load borne by one of them that is assigned to form a larger luminance distribution (for example, wide-zone divided luminance distribution) can relatively become larger, and as a result, that optical deflector assigned to form the larger luminance distribution may likely be damaged. Contrary to this, when the luminance distributions assigned to the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) are changed at a predetermined timing, specifically, when the luminance distributions are changed to luminance distributions with different sizes from each other among the optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3), and that are luminance distributions different in size from those assigned to the optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) before the predetermined timing (mode change), the loads borne by the respective optical deflectors 201.sub.(1), 201.sub.(2), and 201.sub.(3) are averaged in the vehicle lighting fixture 500A of the presently disclosed subject matter.
(424) According to this exemplary embodiment, the vehicle lighting fixture 500A can form a predetermined light distribution pattern that has a relatively high light intensity in part and is a gradually decreased pattern having changing light intensities decreasing from the position of relatively high light intensity toward the periphery. For example, the center light intensity is relatively high and then the light intensity is gradually decreased therefrom to the periphery, and the resulting light distribution pattern can be suitable for far-distance visibility and have an excellent light distribution sense of feeling.
(425) These advantageous effects can be derived from the first luminance distribution (wide-zone luminance distribution), the second luminance distribution (middle-zone luminance distribution) smaller than the first luminance distribution and configured to overlap the first luminance distribution, and the third luminance distribution (hot-zone luminance distribution) smaller than the second luminance distribution and configured to overlap the second luminance distribution. These light luminance distributions can form a first light intensity distribution, a second light intensity distribution, and a third light intensity distribution, each having a higher light intensity and a smaller size in this order. The predetermined light distribution pattern can be formed by projecting these first light intensity distribution, second light intensity distribution, and third light intensity distribution.
(426) The above-described respective exemplary embodiments have dealt with the case where white images corresponding to a predetermined pattern are formed (drawn) on the wavelength converting member 18 (corresponding to the screen member of the presently disclosed subject matter) by irradiating the wavelength converting member 18 with excitation light rays from the excitation light sources 12. However, this configuration is not limitative, and the excitation light source 12 may be composed of a white light source, such as a white laser light source. Such a white laser light source can be configured by, for example, introducing RGB laser light rays into an optical fiber for mixing them. Furthermore, a combination of a blue LD element and a YAG phosphor wavelength converting member emitting yellow light may be used.
(427) When a white light source is used in place of the excitation light source 12, the process of wavelength conversion is not necessary. Therefore, a diffusing member may be used in place of the wavelength converting member 18. In this case, white laser light rays emitted from the white laser light source can scan the diffusing member by the optical deflectors 201 to thereby form (draw) a white image corresponding to a predetermined light distribution pattern.
(428) The diffusing member may be a diffusion plate configured to diffuse the laser light and preferably having the same shape as that of the wavelength converting member 18. Examples of the material for the diffusing member may include a complex material (sintered body) of alumina and YAG not containing any activator (such as Ce) (for example, a material containing 75% Al.sub.2O.sub.3 and 25% YAG), a complex material of YAG and glass, a material containing alumina with bubbles dispersed therein, and a material containing glass with bubbles dispersed therein.
(429) When such a white light source and a diffusing member are used in the above-described exemplary embodiments in place of the excitation light source 12 and the wavelength converting member 18, respectively, the respective optical deflectors 201 can form the luminance distributions assigned thereto with the white light from the white light source on the diffusing member serving as the screen member. Accordingly, the same advantageous effects can also be obtained in this case.
(430) Furthermore, the respective numerical values employed in the respective exemplary embodiments, modified examples, examples, and reference examples are illustrative, and therefore, any suitable numerical value can be adopted for the purpose of the achievement of the vehicle lighting fixture of the presently disclosed subject matter.
(431) It will be apparent to those skilled in the art that various modifications and variations can be made in the presently disclosed subject matter without departing from the spirit or scope of the presently disclosed subject matter. Thus, it is intended that the presently disclosed subject matter cover the modifications and variations of the presently disclosed subject matter provided they come within the scope of the appended claims and their equivalents. All related art references described above are hereby incorporated in their entirety by reference.