ADAPTIVE ILLUMINATION METHOD FOR VEHICLE HEADLIGHT

Abstract

The invention describes a method of providing an illumination pattern for vehicle lighting, the method comprising the steps of: providing a light pattern comprising a multitude of scanlines of white light by illuminating a light converter by means of a scanning laser arrangement for illuminating an area, wherein the scanlines are characterized by a defined scanline width; adapting a cut-off of the light pattern by changing a position of at least one scanline with respect to a reference illumination pattern or by dimming at least a limited portion of at least one scanline.

The invention further describes a vehicle headlight system and a computer program product.

Claims

1. A method of providing an illumination pattern for vehicle lighting, the method comprising the steps of: providing a light pattern comprising a multitude of adjacent scanlines of white light, being arranged in a reference illumination pattern, by illuminating a light converter by means of a scanning laser arrangement for illuminating an area, wherein the scanlines are characterized by a defined scanline width; adapting a cut-off of the light pattern by switching off at least a part of a scanline to provide a non-continuous scanline and by illuminating an area previously illuminated by the non-continuous scanline by controlling the scanning laser arrangement for changing a position of a continuous scanline adjacent to the non-continuous scanline with respect to the reference illumination pattern, wherein the adjacent scanlines overlap with each other, or by dimming by changing over time an intensity of the white light of at least a limited portion of at least one scanline for providing for traffic participants a smoother impression of the adaptation of the cut-off than obtained without such dimming.

2. The method according to claim 1, wherein the position of the continuous scanline adjacent to the non-continuous scanline is changed by expanding a distance between at least two continuous scanlines, wherein one of the at least two continuous scanlines is the continuous scanline adjacent to the non-continuous scanline.

3. The method according to claim 2, wherein the method comprises the additional step of: stepwise decreasing the distance between the at least two scanlines in a subsequent step after expanding the distance.

4. The method according to claim 1, wherein the method comprises the additional step of: providing at least two adjacent non-continuous scanlines; and decreasing a distance between the at least two adjacent non-continuous scanlines.

5. The method according to claim 1, wherein the method comprises the additional step of: adapting an intensity of at least one scanline such that an integral intensity of at least two adjacent scanlines is adapted to a change of a distance between the two adjacent scanlines.

6. The method according to claim 1, wherein the position of the continuous scanline adjacent to the non-continuous scanline is changed by simultaneously changing a position of all the scanlines.

7. The method according to claim 1, wherein the step of switching off at least a part of a scanline comprises the step of: providing a gap in the at least one scanline; and increasing the gap along a longitudinal extension of the at least one scanline.

8. The method according to claim 1, wherein, within the dimming step, the intensity of the white light within the limited portion of the at least one scanline is exponentially changed within a first time period of the dimming.

9. A vehicle headlight system comprising: at least one laser, wherein the at least one laser is adapted to emit laser light with a laser peak emission wavelength, a light converter, wherein the light converter is adapted to convert the laser light to converted light, wherein a peak emission wavelength of the converted light is in a longer wavelength range than the laser peak emission wavelength, a scanner, wherein the scanner is adapted for illuminating the light converter to provide a light pattern comprising a multitude of adjacent scanlines of white light, being arranged in a reference illumination pattern, wherein the scanlines are characterized by a defined scanline width, a controller, wherein the controller is adapted to control a cut-off of the light pattern by switching off at least a part of a scanline to provide a non-continuous scanline and by illuminating an area previously illuminated by the non-continuous scanline by controlling the scanner for changing a position of a continuous scanline adjacent to the non-continuous scanline with respect to the reference illumination pattern, wherein the adjacent scanlines overlap each other, or by dimming by changing over time an intensity of the white light of at least a limited portion of at least one scanline for providing for traffic participants a smoother impression of the control of the cut-off than obtained without such dimming.

10. A computer program product comprising code means which can be saved on at least one memory device comprised by a vehicle headlight system or on at least one memory device of a control device coupled with the vehicle headlight system, wherein the code means are arranged such that the method according to claim 1 can be executed by means of at least one processing device comprised by the vehicle headlight system or by means of at least one processing device of the control device coupled with the vehicle headlight system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0048] The invention will now be described, by way of example, based on embodiments with reference to the accompanying drawings.

[0049] In the drawings:

[0050] FIG. 1 shows a principal sketch of a vehicle headlight system

[0051] FIG. 2 shows a principal sketch of a first illumination pattern

[0052] FIG. 3 shows a principal sketch of a second illumination pattern

[0053] FIG. 4 shows a principal sketch of third illumination pattern

[0054] FIG. 5 shows a principal sketch of fourth illumination pattern

[0055] FIG. 6 shows a principal sketch of a fifth illumination pattern

[0056] FIG. 7 shows a principal sketch of sixth illumination pattern

[0057] In the Figures, like numbers refer to like objects throughout. Objects in the Figures are not necessarily drawn to scale.

DETAILED DESCRIPTION OF EMBODIMENTS

[0058] FIG. 1 shows a principal sketch of a vehicle headlight system 200. The vehicle headlight system 200 comprises at least one laser 212. The at least one laser 212 is adapted to emit laser light 15 with a laser peak emission wavelength. The peak emission wavelength is preferably in the blue wavelength range. The vehicle headlight system 200 further comprises a light converter 220. The light converter 220 is adapted to convert the laser light 15 to converted light 20, wherein a peak emission wavelength of the converted light 20 is in a longer wavelength range than the laser peak emission wavelength. The peak emission wavelength of the converted light 20 is preferably in the yellow wavelength range. The vehicle headlight system 200 further comprises a scanner 214. The scanner 214 is adapted to provide a light pattern comprising a multitude of scanlines on the light converter 220. The at least one laser 212 and the scanner 214 are arranged in a scanning laser arrangement 210 which is coupled to a controller 240 which is in this case an integrated part of the vehicle headlight system 200. The vehicle headlight system 200 may be part of a vehicle headlight. The scanner is in this case a MEMS micro mirror. The controller 240 is adapted to control a cut-off of the light pattern by changing a position of at least one scanline with respect to a reference illumination pattern or by dimming at least a limited portion of at least one scanline. The controller 240 is arranged to control the micro mirror such that a position of the scanline on the light converter 220 is shifted. Hence, an illumination pattern comprising a mixture of laser light 15 and converted light 20 which is projected by means of an optical arrangement 250 can be changed. The optical arrangement 250 may comprise one, two, three or more optical elements like lenses, mirrors, apertures and the like. The controller 240 is further arranged to dim the laser light 15 or to adapt the intensity of the laser light 15 in order to provide a smooth illumination pattern.

[0059] FIG. 2 shows a principal sketch of a first illumination pattern 100. The normal approach to create the image on the phosphor is by line scanning FIG. 2 shows a straightforward line-scanning pattern. There are 14 scanlines, and the laser jumps downward from line 1 to line 3, from 3 to 5, etc., leaving gaps which are filled on the way back upwards (well-known interleaving). The scanlines 110 have a defined scanline width which is essentially defined by a diameter of the laser spot on the light converter essentially perpendicular to a scanning direction indicated by the arrows. The first illumination pattern 100 shows a reference illumination pattern in which no adaption of the scanlines 110 has been performed in order to adapt the illumination pattern to an object which may appear in an area illuminated by the illumination pattern 100.

[0060] FIG. 3 shows a principal sketch of a second illumination pattern 100. The second illumination pattern 100 is again a reference illumination pattern with 11 scanlines 110. The abscissa 102 denotes the number of the scanline 110. The ordinate 101 shows the relative position of the respective scanline 110 on the light converter. The scanlines 110 have a scanline width 113 as described above and a distance between two scanlines 110 is given by X0 which is in this case the same for all scanlines 110. The scanlines 110 overlap such that the light converter is illuminated by means of laser light of two scanlines 110 up to the upper and lower edge (first and eleventh scanline) of the light converter. The scanlines 110 may, for example, be scanned one after the other (non-interleaving) or in an interleaving sequence, e.g. as described above. The numbering does not necessarily describe the sequence of scanning.

[0061] The reference illumination patterns shown in FIG. 2 and FIG. 3 show simple examples of reference illumination patterns. In general, the distance between the scanlines has not to be the same. Furthermore, one or more of the scanlines 110 may be curved or may comprise even corners in order to provide more complicated reference illumination patterns.

[0062] FIG. 4 shows a principal sketch of a third illumination pattern 100. The third illumination pattern 100 is generated by means of a first embodiment of the inventive method. The third illumination pattern 100 comprises 14 scanlines 110 wherein scanlines 1-9 are non-continuous scanlines 111 and scanlines 10-14 are continuous scanlines 112. The illumination pattern 100 comprises an illumination window 116. The illumination window 116 is generated by switching off in subsequent steps a part of the first, second, third etc. scanlines 110 such that the illumination pattern 100 becomes U-shaped. A dashed line shows a cut-off 114 within the illumination window 116 before the respective part of scanline 9 was switched off. The distance between the scanlines 110 is again X0 and the scanline width is 113. The change or shift of the cut-off 114 is reduced by moving or shifting all scanlines 110 around one third of a scanline width 113 to the top as indicated by the arrow on the left side as soon as the part of the ninth scanline 110 is switched off. The shift of the scanlines 110 is preferably performed in a way that original characteristic (straight line in this case) is not changed. The shift may therefore be performed during a step between two scanlines 110. The laser may be switched off in this intermediate phase. This is preferably performed in all embodiments comprising a change of a position of a scanline 110.

[0063] FIG. 5 shows a principal sketch of a fourth illumination pattern 100. The fourth illumination pattern 100 is generated by means of the inventive method according to a second embodiment. The illumination pattern 100 is again U-shaped as described with respect to FIG. 4. The distance between continuous scanlines 112 (scanlines 10-14) is increased from X0 to X1 as soon as a part of scanline 9 is switched off in order to reduce the shift of the cut off 114. The distance between the non-continuous scanlines 111 is unchanged (X0).

[0064] FIG. 6 shows a principal sketch of a fifth illumination pattern 100 generated by means of the inventive method according to a third embodiment. FIG. 6 shows a kind of side view of the illumination pattern 100 as already shown and discussed with respect to FIG. 3. The illumination pattern 100 is again U-shaped. The distance between continuous scanlines 112 (scanlines 1-4) is increased from X0 to X1 as soon as a part of scanline 5 is switched off in order to reduce the shift of the cut-off (not shown). The distance between the non-continuous scanlines 111 (scanlines 5-11) is additionally decreased from X0 to X2.

[0065] FIG. 7 shows a principal sketch of a sixth illumination pattern 100 generated by means of the inventive method according to a fourth embodiment. The sixth illumination pattern 100 comprises 14 scanlines 110 wherein scanlines 3-9 are non-continuous scanlines 111 and scanlines 1, 2 and 10-14 are continuous scanlines 112. The illumination pattern 100 comprises an illumination window 116. The illumination window 116 is generated by switching off in subsequent steps a part of the third, fourth, fifth etc. scanline such that the illumination pattern 100 becomes O-shaped. A dashed line shows a cut-off 114 within the illumination window 116 before the respective part of scanline 9 was switched off. The distance between the continuous scanlines 112 is again X0 and the scanline width is 113. The change or shift of the cut-off 114 is at least subjectively reduced by providing a small gap in in the ninth scanline between a first part 9a and a second part 9b. The gap is increased step-by-step along a longitudinal extension of the ninth scanline as indicated by the double arrow. The dark parts in the third, fourth and fifth scanlines may be opened in the same way in a step by step approach one after the other in order to open the window 116. Alternatively, two, three, four or more scanlines may be darkened simultaneously.

[0066] While the invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive.

[0067] From reading the present disclosure, other modifications will be apparent to persons skilled in the art. Such modifications may involve other features which are already known in the art and which may be used instead of or in addition to features already described herein.

[0068] Variations to the disclosed embodiments can be understood and effected by those skilled in the art, from a study of the drawings, the disclosure and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality of elements or steps. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0069] Any reference signs in the claims should not be construed as limiting the scope thereof.

LIST OF REFERENCE NUMERALS

[0070] 9a first part of a non-continuous scanline [0071] 9b second part of a non-continuous scanline [0072] 15 laser light [0073] 20 converted light [0074] 100 illumination pattern [0075] 101 position of scanline on the light converter [0076] 102 number of scanline [0077] 110 scanline [0078] 111 non-continuous scanline [0079] 112 continuous scanline [0080] 113 scanline width [0081] 114 cut-off [0082] 116 illumination window [0083] 200 vehicle headlight system [0084] 210 scanning laser arrangement [0085] 212 laser [0086] 214 scanner [0087] 220 light converter [0088] 240 controller [0089] 250 optical arrangement [0090] X0 distance between scanlines in reference illumination pattern [0091] X1 increased distance between two continuous scanlines [0092] X2 decreased distance between two non-continuous scanlines