Lighting Apparatus for a Motor Vehicle

Abstract

A lighting apparatus for a motor vehicle has a lighting module. The lighting module includes a laser light source for generating laser light, the laser light source having one or more laser diodes. The module includes an optical device onto which the laser light is incident and which is designed such that it generates a predefined symbol in the surroundings of the motor vehicle. The optical device has one or more holographic optical elements which are substantially non-absorbent to the laser light and which are designed to effect interference of the laser light by phase modulation thereof in order to generate the predefined symbol. The module includes an actuator system for moving at least one part of the lighting module. The actuator system has one or more actuators. A control device actuates the actuator system during operation of the illuminating device such that the position of the predefined symbol relative to the motor vehicle and/or the shape of the predefined symbol are changed by the actuator system.

Claims

1. A lighting apparatus for a motor vehicle, comprising: a light module, wherein the light module comprises: a laser light source for generating laser light, wherein the laser light source comprises one or more laser diodes; an optical device on which the laser light is incident and which is configured such that the optical device generates a predefined symbol arrangement in an area surrounding the motor vehicle, wherein the optical device comprises one or more holographic optical elements which are substantially non-absorbent to the laser light and which are configured to produce interference of the laser light by phase modulation thereof in order to generate the predefined symbol arrangement; an actuator system for moving at least a portion of the light module, wherein the actuator system comprises one or more actuators; and a control device with which the actuator system is actuated during operation of the lighting apparatus such that a position of the predefined symbol arrangement relative to the motor vehicle and/or a form of the predefined symbol arrangement are changed via the actuator system.

2. The lighting apparatus according to claim 1, wherein the one or more holographic optical elements comprise one or more diffractive optical elements.

3. The lighting apparatus according to claim 1, further comprising: a light device that generates a predefined light distribution in addition to the predefined symbol arrangement.

4. The lighting apparatus according to claim 3, wherein the light device is a headlamp configured to generate low beam and/or high beam distribution as the predefined light distribution, and/or the light device is a vehicle signaling lamp configured to generate a light signal as the predefined light distribution.

5. The lighting apparatus according to claim 4, wherein the vehicle signaling lamp is a rear light and/or a brake light.

6. The lighting apparatus according to claim 3, wherein when the light device is switched on and the light module is switched on, the predefined symbol arrangement is superimposed with the predefined light distribution.

7. The lighting apparatus according to claim 1, wherein the optical device comprises at least one mirror on which the laser light is incident after passing the one or more holographic optical elements, and the at least one mirror is movable by at least one predefined actuator of the actuator system by way of actuation by the control device.

8. The lighting apparatus according to claim 7, wherein the at least one predefined actuator is configured to execute an oscillating movement of the at least one mirror during operation of the lighting apparatus, wherein a path of the oscillating movement describes the form of the predefined symbol arrangement.

9. The lighting apparatus according to claim 8, wherein the path and/or a speed of the oscillating movement of the at least one mirror are freely adjustable.

10. The lighting apparatus according to claim 1, wherein at least one predetermined actuator of the actuator system is provided so as to produce a relative movement between the one or more holographic optical elements and the laser light before passing the one or more holographic optical elements during operation of the lighting apparatus by way of actuation by the control device, as a result of which light is alternately shone onto different holographic optical structures which are constituent parts of the one or more holographic optical elements.

11. The lighting apparatus according to claim 10, wherein the relative movement is an oscillating relative movement.

12. The lighting apparatus according to claim 10, wherein only the one or more holographic optical elements, only the laser light source, or both the one or more holographic optical elements and the laser light source, are movable by the at least one predetermined actuator.

13. The lighting apparatus according to claim 1, wherein the laser light source is an RGB laser light source which comprises a number of red laser diodes, a number of green laser diodes and a number of blue laser diodes, a first holographic optical structure on which the red laser light of the number of red laser diodes is incident is associated with the number of red laser diodes, a second holographic optical structure on which the green laser light of the number of green laser diodes is incident is associated with the number of green laser diodes, and a third holographic optical structure on which the blue laser light of the diodes is incident is associated with the number of blue laser diodes, the first, second and third holographic optical structures are constituent parts of the one or more holographic optical elements, and the light module is configured such way that the red, green and blue laser light is superimposed after passing the first, second and third holographic optical structures and as a result the predefined symbol arrangement is generated in white light.

14. The lighting apparatus according to claim 1, wherein the control device is configured to receive information from a surrounding area sensor system and/or a navigation system of the motor vehicle and to actuate the actuator system depending on said information.

15. The lighting apparatus according to claim 14, wherein the control device is configured to extract or ascertain a course of a roadway in front of the motor vehicle from said information of the surrounding area sensor system and match the form of the predefined symbol arrangement to the course of the roadway.

16. The lighting apparatus according to claim 15, wherein the predefined symbol arrangement comprises one or more lines, the form of said lines being matched to a curvature of the course of the roadway.

17. The lighting apparatus according to claim 14, wherein the control device is configured to output a turn-off instruction as a predefined symbol arrangement based on the information of the navigation system when the motor vehicle is approaching a junction on a navigation route along which the navigation system is currently navigating, and the turn-off instruction signals continued travel on the navigation route and wherein the turn-off instruction is arranged at a site of the junction and maintains this position as the motor vehicle approaches.

18. A motor vehicle comprising one or more lighting apparatuses according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a schematic illustration which shows a first embodiment of a light module in a lighting apparatus according to the invention.

[0035] FIG. 2 is a schematic illustration which shows a second embodiment of a light module in a lighting apparatus according to the invention.

[0036] FIG. 3 and FIG. 4 show different plan views of motor vehicles comprising the lighting apparatus according to the invention, wherein the generation of different symbol arrangements is illustrated.

DETAILED DESCRIPTION OF THE DRAWINGS

[0037] One embodiment of the invention will be described below using a lighting apparatus in the form of a front headlamp of a motor vehicle. The front headlamp contains, in a manner which is known per se, a light device with which the low beam and the high beam are generated, wherein said light device is not shown in the figures. In addition to this light device, a light module is installed in the headlamp, which light module can generate a specific symbol arrangement on the road in front of the motor vehicle in parallel to the low beam or high beam.

[0038] FIG. 1 shows a first embodiment of a light module of this kind. The light module is denoted by reference symbol 10 overall and, in the embodiment described here, comprises a laser light source 1 with three laser diodes 101, 102 and 103 and also three collimator lenses 3, 3, 3. The laser diode 101 is a red laser diode, the laser diode 102 is a green laser diode, and the laser diode 103 is a blue laser diode. The light of the respective laser diodes is indicated by arrows which start from said diodes. The laser light of the individual diode is initially collimated by the collimator lenses 3, 3 and 3. In this case, the collimator lens 3 collimates the red laser light of the laser diode 101, the collimator lens 3 collimates the green laser light of the laser diode 102, and the collimator lens 3 collimates the blue laser light of the laser diode 103. The collimated laser light beams are then incident on the merely schematically indicated transmissive holographic optical element 2. Owing to the structuring on the bottom side of the element, phase modulation and interference of the incident laser beams is produced in the process.

[0039] In the embodiment described here, a single continuous holographic optical element 2 which has corresponding holographic optical structures 201, 202 and 203 for the different laser light beams is used. In this case, the red laser light beam is incident on the holographic optical structure 201, the green laser light beam is incident on the holographic optical structure 202, and the blue laser light beam is incident on the holographic optical structure 203. In FIG. 1, the red laser light beam is denoted by reference symbol L after passing the structure 201, the green laser light beam is denoted by reference symbol L after passing the structure 202, and the blue laser light beam is denoted by reference symbol L after passing the structure 203.

[0040] The light beams L, L and L are initially incident on a tiltable mirror 5, wherein the tilting movement is schematically indicated by two double-headed arrows DP. An actuator 6, merely schematically indicated, is used for generating the tilting of the mirror 5. In this case, the mirror and the actuator can form a so-called MEMS component (MEMS=Micro Electro Mechanical System). In a component of this kind, the mirror and the actuator are integrated in a common chip. The actuator 6 is actuated by a control device 7, that is to say the actuator moves the mirror 5 depending on corresponding control signals of the control device 7. In the embodiment described here, the mirror 5 forms, in combination with the actuator 6 and the control device 7, a vector scanner which can execute an oscillating movement of the mirror, wherein the form of the oscillating movement and the speed thereof can be adjusted as desired. In this case, the vector scanner can also execute slow continuous movements and assume any desired tilting positions in line with the possible tilting of the mirror. The laser light beams L, L and L which are reflected at the mirror 5 are cast onto the road 4 in front of the motor vehicle.

[0041] The structures 201 to 203 of the holographic optical element 2 are configured in such a way that the individual light beams L, L and L produce the same symbol arrangement at the same point on the road 4, so that a superimposed symbol arrangement SY appears in white at this point. In this case, the brightness of the symbol arrangement is greater than the brightness of the low beam or high beam, so that the symbol arrangement is distinguished from the low beam and high beam and therefore is visible to the driver of the motor vehicle and, respectively, to other road users. In the embodiment of FIG. 1, the phase-modulated laser light which is reflected by the mirror 5 is cast directly onto the road 4. However, if desired, yet further optical elements, such as one or more lenses for example, can also be provided in the beam path downstream of the mirror.

[0042] In the embodiment of FIG. 1, the symbol arrangement SY can be positioned at different points by changing the tilting of the mirror 5, and dynamic light effects are produced in this way. However, the symbol arrangement can possibly also be produced by a predefined scanning movement of the three superimposed light beams L, L and L, wherein the movement of the light beams can no longer be perceived by the human eye given a sufficient oscillation frequency. In this way, lines, for example, can be produced as the symbol arrangement, it being possible for the curvature of said lines to be adapted in a suitable manner by changing the scanning movement of the mirror 5. A symbol arrangement which is produced by means of a scanning movement is shown in FIG. 3 which is described further below.

[0043] FIG. 2 shows a second variant of a light module 10 which can be used in the lighting apparatus according to the invention. In this case, the structure of the laser light source 1 having corresponding laser diodes 101 to 103 and collimator lenses 3 to 3 corresponds to the laser light source from FIG. 1, and therefore reference is made to the explanations relating to said figure. In contrast to FIG. 1, the holographic optical element 2 is now not formed only from three holographic optical elements 201 to 203, but rather from a matrix of a total of 15 holographic optical structures, wherein the holographic optical element 2 is shown in perspective for the purpose of illustrating said matrix. The matrix-like holographic optical element contains, in the first row, five holographic optical structures 201 which differ from one another and can be illuminated only by the laser light of the red laser diode 101. In contrast, the second row of the matrix comprises the five holographic structures 202 which can be illuminated only by the green laser diode 102 and differ from one another. Analogously, the lowermost row of the matrix comprises the five holographic optical structures 203 which differ from one another and can be illuminated only by the blue laser diode 103. For reasons of clarity, only some of the holographic optical structures are denoted by the reference symbols 201, 202 and 203.

[0044] In the embodiment of FIG. 2, the holographic optical element 2 can be moved by means of a corresponding actuator 6 which, in turn, can be actuated by way of a control device 7. In this case, the holographic optical element 2 can be shifted in the horizontal direction, as is indicated by the arrow P. In this way, the laser light source can illuminate different columns of holographic optical structures 201 to 203. When illuminating a corresponding column of holographic optical structures, the three laser light colors are phase-modulated, in response to which the red laser light beam L, the green laser light beam L and the blue laser light beam L are directed onto a common point on the road 4 and are superimposed there to form a white symbol arrangement SY. In FIG. 2, this superimposition is indicated, by way of example, for the illumination of the left-hand-side column of the holographic optical structures 201 to 203 and also the fourth column from the left of the holographic optical structures. The holographic optical structures of the individual columns each produce the same symbol arrangement SY, but in a different position on the road 4.

[0045] By way of the embodiment of FIG. 2, the symbol arrangement SY can be shifted to and fro between different positions on the road 4 in front of the motor vehicle. In this case, a periodic movement of the holographic optical element 2 can also be optionally carried out, so that a continuous change in the position of the symbol arrangement on the road is achieved, as a result of which the symbol arrangement is better perceived by the driver or other road users.

[0046] In the embodiment of FIG. 2, a relative movement between the laser light source 1 and the holographic optical element 2 was produced only by the movement of the holographic optical element. Nonetheless, it is also possible for this relative movement to be generated only by the movement of the laser light source 1 or by simultaneous movement of the laser light source 1 and of the holographic optical element 2 by way of another actuator or further actuators.

[0047] FIG. 3 and FIG. 4 illustrate, by way of example, what types of symbols can be generated by means of the lighting apparatus according to the invention. Both figures show different plan views of a motor vehicle 8 which is traveling on a right-hand-side lane on a roadway. The direction of travel is the upward direction in FIG. 3 and FIG. 4. In the two figures, the right-hand-side roadway edge is denoted by reference symbol FR, the left-hand-side roadway edge is denoted by reference symbol FL, and the central strip is denoted by reference symbol ML. In this case, the individual symbol arrangements generated are optionally generated by a light module according to the invention in the left-hand-side front headlamp and a light module according to the invention in the right-hand-side front headlamp of the motor vehicle 8.

[0048] FIG. 3 shows the generation of a symbol arrangement in the form of two solid lines LI. This symbol arrangement is generated by means of the scanning light module of FIG. 1, wherein the form of the lines is specified by the scanning movement of the scanning mirror. As shown in FIG. 3, the lines LI depict the course of the roadway in front of the motor vehicle. In order to achieve this, the control device of the corresponding light modules receives sensor signals from a surrounding area sensor system of the motor vehicle 8, which surrounding area sensor system detects the future course of the motor vehicle on the roadway. In this case, the surrounding area sensor system is preferably a camera-based sensor system. By means of the sensor signals of the surrounding area sensor system, the two lines LI are then generated in such a way that they follow the future course of the roadway. Since the course of the roadway in FIG. 3 is curved, this also leads to curved lines being represented.

[0049] FIG. 4 shows a scenario in which a turn-off arrow P is represented on the roadway at a junction AB as a symbol. Said arrow is preferably also generated by the light module of FIG. 1, wherein in this case the mirror does not oscillate but rather slowly changes its tilting position. In this case, the arrow P corresponds to the symbol arrangement which results from superimposing the three laser light beams L, L and L of FIG. 1. For illustrative purposes, the light of the two headlamps is further shown in FIG. 4 and denoted by corresponding reference symbol SL.

[0050] In the embodiment of FIG. 4, the control device of the corresponding light modules receives, from the navigation system of the motor vehicle 8, information relating to the currently set navigation route and the position of the motor vehicle on this route. In this case, the control system identifies that the motor vehicle is approaching the junction AB and, according to the navigation route, the journey should continue toward the right at the junction. As a consequence, the arrow P toward the right is generated in the position of the junction AB. As the vehicle continues to approach the junction AB, said arrow is constantly held in this position by means of the actuator system in the light module. In other words, a relative movement between the arrow P and the motor vehicle 8 is carried out in such a way that the arrow P remains at the site of the junction AB until the vehicle reaches the junction. In this way, the driver of the motor vehicle is intuitively informed about which direction he has to take at the junction as the vehicle approaches the junction.

[0051] The embodiments of the invention described above have a range of advantages. In particular, a predefined symbol arrangement can be generated in the area surrounding the motor vehicle by a motor vehicle lighting apparatus in a simple manner by means of one or more non-absorbent holographic optical elements. In this case, the holographic optical elements cause phase modulation, without reducing the light amplitude by absorption, so that largely no light losses occur. In this case, sufficient brightness of the symbol arrangement is ensured by means of a laser light source. Furthermore, the symbol arrangement is provided with a degree of dynamism by means of the actuator system and a control device to the effect that the symbol arrangement can change its form and/or position. In particularly preferred embodiments, the generation of the symbol arrangement is linked to information from a navigation system or a surrounding area sensor system. Owing to the use of information of a navigation system, the driver can be provided with turn-off instructions in a dynamic manner for example. When using information of a surrounding area sensor system, the course of the roadway in front of the motor vehicle for example can be displayed by means of the symbol arrangement.

LIST OF REFERENCE SYMBOLS

[0052] 1 Laser light source [0053] 101, 102, 103 Laser diodes [0054] 2 Holographic optical element [0055] 201, 202, 203 Holographic optical structures [0056] 3, 3, 3 Collimator lenses [0057] 4 Road [0058] 5 Mirror [0059] 6 Actuator [0060] 7 Control device [0061] 8 Motor vehicle [0062] L, L, L Laser light beams [0063] SY Symbol arrangement [0064] DP Double-headed arrows [0065] FL, FR Roadway edges [0066] ML Central strip [0067] LI Lines [0068] P, P Arrows [0069] AB Junction [0070] SL Headlamp light

[0071] The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.