Light device, especially a projector system of a headlight for motor vehicles

Abstract

A light device comprises a laser light source, a primary optical system with at least one diffractive and/or at least one reflective optical element to convert monochromatic coherent light to a collimated beam of coherent light, a MOEMS comprising one or more micro-mirrors to route coherent light and convert it to white light, and a secondary optical system comprising at least one diffractive and/or at least one reflective optical element to direct white light from the light device to create a light pattern on the display surface and/or in specific zones in front of the vehicle. It further comprises an electromagnetic control system connected to the MOEMS and the light source to control changes of rotation angle, oscillation angle and oscillation rate and frequency of one of the micro-mirrors, and to control the light source activity, for controlled changing of the shape and/or position of the light pattern depending on current conditions of the vehicle.

Claims

1. A light device, especially the projector system of a headlight for motor vehicles comprising a laser light source, a primary optical system with at least one diffractive optical element or with at least one reflective optical element to convert the monochromatic coherent light produced by the laser light source to a collimated beam of coherent light, a MOEMS comprising one or more micro-mirrors to route coherent light to a converter to convert the coherent light to white light, and a secondary optical system comprising at least one diffractive optical element or at least one reflective optical element to direct the white light further out of the light device and to create a light pattern on the display surface or in specific zones in front of the driver on a roadway, wherein the light device comprises a modulator situated between the laser light source and the secondary optical system along the route of a beam of light rays produced by the laser light source and advancing from this source to the secondary optical system, to influence the light characteristic of at least part of the beam, the light source further comprising an electromagnetic control system connected to the MOEMS and to the laser light source to control, through transmission of electric or electromagnetic signals, changes of the rotation angle, changes of the oscillation angle and changes of the oscillation rate and frequency of the free end of at least one of the micro-mirrors, and to control the activity of the laser light source, for controlled changing of the shape and/or position of the light pattern depending on current conditions where the vehicle finds itself during the vehicle's operation.

2. The light device in accordance with claim 1, wherein the light device comprises just one laser light source.

3. The light device in accordance with claim 1, wherein the electromagnetic control system is connectable to an output of one or more information means in the form of signals which data collected by information means about the current conditions where the vehicle finds itself during the vehicle's operation have been transformed into.

4. The light device in accordance with claim 1, wherein the modulator is situated between the laser light source and the primary optical system to influence the light characteristic of at least part of the laser beam of coherent light.

5. The light device in accordance with claim 1, wherein the modulator is situated between the primary optical system and the secondary optical system to influence the light characteristic of at least part of the collimated light beam.

6. The light device in accordance with claim 1, wherein the primary optical system further comprises a divider to divide the collimated beam into more separate light streams.

7. The light device in accordance with claim 6, wherein the primary optical system comprises a modulator of the light stream.

8. The light device in accordance with claim 1, wherein the modulator is configured to interrupt or deflect at least a part of a beam of light rays, especially a light stream, to produce one or more unlit areas in the light pattern.

9. The light device in accordance with claim 1, wherein the modulator is connected to an electromagnetic control system that controls the operation of the modulator, especially with respect to the current conditions where the vehicle finds itself during the vehicle's operation.

10. The light device in accordance claim 1, wherein the said at least one of the micro-mirrors is arranged in a movable manner in such a way that at least one of the micro-mirrors can be rotated in a controlled manner around a first axis, which is identical with the axis around which the micro-mirror can be oscillated in a controlled way.

11. The light device in accordance with claim 10, wherein the said at least one of the micro-mirrors is arranged in a movable manner in such a way that it can also be rotated in a controlled manner around a second axis around which the micro-mirror can also be oscillated in a controlled way.

12. The light device in accordance with claim 11, wherein the second axis lies on a horizontal plane and is perpendicular to the first axis.

13. The light device in accordance with claim 11, wherein the said at least one of the micro-mirrors is mounted in a movable first carrying frame with the possibility of controlled rotation and oscillation of the micro-mirror in this first frame around the said first axis, this first frame being arranged in such a way that the first frame can be rotated and oscillated around the said second axis in a controlled way.

14. The light device in accordance with claim 13, wherein the first carrying frame is mounted in a movable way in a static second carrying frame.

15. The light device in accordance with claim 1, wherein information means are the means used to establish the instantaneous angle, turning direction of the vehicle, its instantaneous speed, or to detect an oncoming vehicle.

16. The light device in accordance with claim 1, wherein the converter comprises a self-contained converter layer and a filter that are in a mutual direct contact.

17. The light device in accordance with claim 16, wherein the self-contained converter layer consists of a monocrystal or ceramic body, especially containing Cr:YAG.

18. The light device in accordance with claim 16, wherein the filter is located in such a way that coherent light that has been directed by one or more micro-mirrors enters the converter through the filter.

19. The light device in accordance with claim 16, wherein the filter is located between a cooler and the self-contained converter layer situated in such a way that coherent light that has been directed by one or more micro-mirrors enters the converter through the self-contained converter layer.

20. The light device in accordance with claim 19, wherein the filter is connected to the cooler by means of a bonding material, especially by melting.

Description

DESCRIPTION OF THE DRAWINGS

(1) The invention will be clarified in a more detailed way with the use of its embodiment examples with references to attached drawings, where:

(2) FIG. 1a shows a schematic representation of the light device according to the invention,

(3) FIGS. 1b to 1e show more embodiment examples of the light device,

(4) FIGS. 2a to 2e show embodiment examples of the primary optical system,

(5) FIGS. 3a to 3g show more embodiment examples of the primary optical system,

(6) FIG. 4a shows an example of the projected light image,

(7) FIG. 4b shows a schematic representation of the position of the micro-mirror of FIG. 4a,

(8) FIG. 4c shows another example of the projected light image,

(9) FIG. 4d shows a schematic representation of the position of the micro-mirror of FIG. 4c,

(10) FIG. 5a shows another example of the projected light image,

(11) FIG. 5b shows a schematic representation of the positions of the micro-mirror of FIG. 5a,

(12) FIG. 5c shows another example of the projected light image,

(13) FIG. 5d shows a schematic representation of the positions of the micro-mirror of FIG. 5c,

(14) FIG. 6a shows another example of the projected light image,

(15) FIG. 6b shows another example of the projected light image,

(16) FIG. 7a shows an electromagnetically controlled MOEMS in two directions,

(17) FIG. 7b shows a part of the electromagnetically controlled MOEMS in 1D,

(18) FIG. 7c shows a part of the electromagnetically controlled MOEMS in 2D,

(19) FIG. 8 shows the structure of the converter in the transmission arrangement, used in the light device in accordance with the invention,

(20) FIG. 9 shows the structure of the converter in the reflective arrangement, used in the light device in accordance with the invention,

(21) FIG. 10a shows shapes of the light stream amplitude, and

(22) FIG. 10b shows more shapes of the light stream amplitude in accordance with the invention.

EXAMPLES OF EMBODIMENTS OF THE INVENTION

(23) FIG. 1a shows a light device, especially a headlight for motor vehicles comprising a laser light source 1 that comprises only one laser diode to produce coherent light 101, and the primary optical system 2 adapted by means of diffractive optical elements 6 to generate a collimated beam 102 of light rays 100 of coherent light 101 and at the same time to create at least one light stream 103 directed to the MOEMS 3. MOEMS 3 represents a micro-opto-electro-mechanical system adapted by means of the electromagnetic control system 11 to control the micro-mirror 31 and to direct the light stream 103 of coherent light 101 towards the converter 4 to convert the coherent light 101 to white light 104. In the propagation direction of the white light 104, the secondary optical system 5 is situated comprising a diffractive optical element 6 to route the light stream 103 further out of the light device in the direction of the optical axis x.

(24) FIG. 1b shows an embodiment of the light device comprising a modulator 9 of coherent light 101 to influence the light characteristic of the laser beam of light rays 100.

(25) FIGS. 1c and 1d show an embodiment of the light device comprising a modulator 9 of the collimated light beam 102 of coherent light 101 of at least one light stream 103.

(26) FIG. 1e shows an embodiment of the light device comprising a modulator 9 of the controlled light stream 103 of coherent light 101 exiting from the MOEMS 3.

(27) FIG. 2a and FIG. 2b show the primary optical system 2 comprising diffractive optical elements 6 comprising an array of lenses 61. FIG. 2c shows the primary optical system 2 comprising diffractive optical elements 6 in the form of lenses 61 and prisms 62. FIG. 2d shows the primary optical system 2 comprising a diffractive optical element 6 in the form of a lens 61 on the one hand, and a reflective optical element 7, e.g. reflector, to direct the collimated beam 102 towards the electromagnetically controlled MOEMS 3, on the other hand. FIG. 2e shows the primary optical system 2 comprising only the reflective optical element 7 to create a collimated beam 102 directed towards the electromagnetically controlled MOEMS 3.

(28) According to FIGS. 3a to 3e, the primary optical system 2 comprises a divider 8 adapted to divide the collimated light beam 102 of coherent light 101 into more separate light streams 103. In another embodiment, shown in FIG. 3b, the primary optical system 2 further comprises modulators 9 of the light streams 103, making it possible to influence the light characteristics of the laser beams of rays 100, or to even completely interrupt the light stream 103 or its part, or to deflect it outside the electromagnetically controlled MOEMS 3.

(29) According to FIG. 3c and FIG. 3e, the electromagnetically controlled MOEMS 3 comprises a micro-mirror 31 for each light stream 103 of coherent light 101. In the embodiments shown in FIG. 3d and FIG. 3e, the primary optical system 2 comprises for each light stream 103 of coherent light 101 a separate diffractive optical element 6.

(30) According to FIG. 3f, the primary optical system 2 comprises an electro-optical modulator 9 of the light beam 102 of coherent light 101 to produce an electro-optically modulated light beam 102a. The modulation is accomplished by influencing the amplitude, polarity or phase of the entire input light beam 102 or its part e.g. in the form of an LCD display or by means of devices used for amplitude, phase and polarizing modulation of light waves (PLM, SLM).

(31) According to FIG. 3g, the primary optical system 2 comprises a mechanical modulator 9 of the light beam 102 of coherent light 101 to produce a mechanically modulated light beam 102b. The modulation is accomplished e.g. by mechanical screening of a part of the input light beam 102, e.g. in the form of a fixed or movable screen or a semipermeable or partly impermeable filter.

(32) FIG. 4a and FIG. 4b show an example of the projected light image and the corresponding micro-mirror 31 wherein the micro-mirror 31 of the MOEMS 3 structure is situated in a static position at the rotation angle with respect to the optical axis X of light propagation to produce the light pattern A on the display surface VH. The light pattern A created from one light stream 103 contributes to creation of the output characteristic of the light trace in specific zones in front of the driver on the carriageway, where in this example, the center of the light pattern A is situated on the display surface VH on the optical axis x. As indicated in FIGS. 4c and 4d, a change of the rotation angle of the micro-mirrors 31 with respect to the optical axis x causes a change of the position of the projected pattern A on the display surface VH so the center of the light pattern produced by the light stream 103 is offset from the direction of the optical axis x on the display surface VH.

(33) As indicated in FIGS. 5a to 5d, oscillation of the micro-mirror 31 at the oscillation angle 1, 2 causes extension/widening of the pattern A. The oscillation angle 1 determines the extension rate in the direction H and the oscillation angle 2 determines the extension rate in the direction +H, i.e. the width d, the height h of the projected pattern A remaining constant. The rotation angles min and a min then determine the rate of the offset of the axes from the optical axis x. The oscillation frequency of the micro-mirror 31 can be constant, or variable and also the angular speed of the free end of the micro-mirror 31 can change on the basis of the current position of the micro-mirror 31 to achieve an even distribution of light in the light pattern A. The instantaneous angular speed can change in such a way as to achieve the required distribution of light.

(34) As shown in FIG. 6a, an unlit area 10 can be created in the light pattern A by switching off of the light source 1 and/or by means of the modulator 9. FIG. 6b shows an output light trace comprising more light patterns A. Each light pattern A consists of one light stream 103 while one or more unlit areas 10 can be produced in each pattern.

(35) FIG. 7a shows an example of mounting of the micro-mirror 31, which is part of the MOEMS 3. The micro-mirror 31 is positioned in the first carrying frame 33, which is movable in this example. The first carrying frame 33 is further set in the second carrying frame 32, which is static in this case, the position of the micro-mirror 31 and/or the first carrying frame 33 being influenced by the electromagnetic control system 11. Electric or electromagnetic signals are used to control the rotation angle and/or the oscillation angle of the micro-mirror 31 with respect to the first carrying frame 33 or the second carrying frame 32, as indicated in FIG. 7b. FIG. 7c shows the rotation angle and/or the oscillation angle of the movable carrying frame 33 with respect to the static carrying frame 32. This way, it is not only the width d, but also the height h of the light pattern A that can be influenced.

(36) According to FIGS. 5a to 5d, the micro-mirror 31 is arranged in a movable way for controlled rotation around the first axis o1 (see FIG. 5b). In the presented preferred embodiment, the first axis o1 is at the same time the axis around which the micro-mirror 31 can be oscillated in a controlled manner. However, in general, the axis around which the micro-mirror 31 is rotated does not have to be identical with the axis around which the micro-mirror 31 oscillates. In addition, in another embodiment, the micro-mirror can also be rotated around the second axis o2 (see FIG. 5b) and it can also be oscillated around the second axis o2. This second axis o2 can be preferably perpendicular to the first axis o1. Rotation and oscillation of the micro-mirror 31 around the second axis o2 provides the possibility to change the shape of the light pattern A and its positionoffset in the vertical direction.

(37) MOEMS 3, the light source 1 and the modulator 109 are connected to the electromagnetic control system 11 for transmitting electric or electromagnetic signals to control the current position of the micro-mirror 31 and its movement in accordance with the current conditions where the vehicle finds itself. The light stream 103 exiting from the primary optical system 2 is influenced in such a way to enable changing of the position of the light pattern A on the display surface VH. E.g. if the vehicle is turning, the light pattern A is shifted in the horizontal direction based on the turning direction through changes of the rotation angle of the micro-mirror 31. The height h and/or width d of the light pattern A changes depending on the vehicle's speed, namely through changes of the oscillation angle of the micro-mirror 31. Light intensities in individual parts of the light pattern A are changed by influencing the rate and frequency of oscillation of the free end of the micro-mirror 31. When an oncoming vehicle is detected, an unlit area 10 can be created in the light pattern A by means of a not represented light control unit connected to the light source 1 and/or modulator 9 while the light control unit and the electromagnetic control system 11 mutually cooperate.

(38) FIG. 8 shows the structure of the converter in the transmission arrangement, used in the light device in accordance with the invention. The converter 4 comprises a self-contained converter layer 71 and a filter 72 that are in mutual direct contact.

(39) For the purposes of this invention, the term self-contained in the phrase self-contained converter layer 71 expresses that the converter layer 71 is so firm that it does not need any carrying layer it would be connected to or supported by.

(40) In the transmission as well as reflective arrangement (FIG. 9), the self-contained converter layer 71 can comprise a monocrystal or ceramic body, especially containing Cr:YAG.

(41) As shown in FIG. 8, the filter 72 is located in such a way that coherent light 101 that has been directed by one or more micro-mirrors 31 enters the converter 4 through it. FIG. 8 indicates that it is the transmission arrangement unlike the reflective arrangement, which is shown in the following FIG. 9.

(42) FIG. 9 shows the structure of the converter 4 in the reflective arrangement, used in the light device in accordance with the invention. In this structure, the filter 72 is situated between the cooler 75 and the self-contained converter layer 71, situated in such a way that coherent light 101 that has been directed by one or more micro-mirrors 31 enters the converter 4 through it. The filter 72 is connected to the cooler 75 by means of a bonding material 77, especially by melting.

(43) In the above mentioned transmission as well as reflective arrangement, the filter 72 can be e.g.: a spectral filter or a polarizing filter, or an optical layer that reflects a certain part of the spectrum and transmits another part or possibly absorbs some parts of the spectrum, an optical layer configured to transmit blue light from the side of the source and to reflect yellow light from the side of the converter, or a semi-permeable filter (e.g. partly metal-plated in some places).

(44) FIG. 10a and FIG. 10b show shapes of the amplitude 111 of the input light streams 103 and various shapes of the amplitude 112 of the modulated light streams 102a influenced by means of the electro-optical modulator 9, and shapes of the amplitude 113 of the modulated light streams 102b influenced by means of the mechanical modulator 9 wherein the amplitude 112 created by means of the electro-optical modulator 9 can be dynamically changed in time and conversely, the amplitude 113 created by means of the mechanical modulator 9 can be changed by spatial positioning (position) of the mechanical modulator 9.

LIST OF REFERENCE MARKS

(45) 1 light source 2 primary optical system 3 MOEMS 4 converter 5 secondary optical system 6 diffractive optical element 7 reflective optical element 8 divider 9 modulator 10 unlit area 11 electromagnetic control system 31 micro-mirror 32 second carrying frame 33 first carrying frame 61 lens 62 prism 71 converter layer 72 filter 75 cooler 77 bonding material 100 light ray 101 coherent light 102 collimated light beam 102a electro-optically modulated light beam 102b mechanically modulated light beam 103 light stream 104 white light 111 amplitude shape 112 modulated amplitude shape 113 modulated amplitude shape O1 first axis O2 second axis H horizontal plane V vertical plane VH display surface X optical axis of the lamp rotation angle min minimum rotation angle max maximum rotation angle oscillation angle 1 oscillation angle 2 oscillation angle A light pattern d pattern width h pattern height offset rate