LIGHTING DEVICE FOR VEHICLE HEADLIGHT

Abstract

A lighting device for a vehicle headlight, the lighting device having a first light module (105), a second light module (106) and a third light module (107), wherein the first light module (105) generates, when installed in a vehicle, a first specified overall light distribution (A) in a region in front of the motor vehicle, and the second light module (106) generates, when installed in a vehicle, a first specified partial light distribution (F) in a region in front of the motor vehicle, and the third light module (107) generates, when installed in a vehicle, a second specified partial light distribution (Z) in a region in front of the motor vehicle, and wherein when the first and second light modules (105, 106) are illuminated at the same time, the first overall light distribution (A) at least partially overlaps the first partial light distribution (F), with the result that a second overall light distribution (AF) is formed, wherein the second partial light distribution (Z) lies underneath the hh line (hh) and at least partially overlaps the second overall light distribution (AF), and wherein when all three light modules (105, 106, 107) are activated simultaneously, a third overall light distribution (AF) is formed.

Claims

1. A lighting device for a vehicle headlight, the light device comprising: a first light module (105); a second light module (106); and a third light module (107), wherein: the first light module (105) is configured to generate a first specified overall light distribution (A) when installed in a vehicle, in a region in front of the vehicle, the second light module (106) is configured to generate a first specified partial light distribution (F) when installed in a vehicle, in a region in front of the motor vehicle, the third light module (107) is configured to generate a second specified partial light distribution (Z) when installed in a vehicle, in a region in front of the motor vehicle, when the first and second light modules (105,106) are illuminated at the same time, the first overall light distribution (A) at least partially overlaps the first partial light distribution (F), such that a second overall light distribution (AF) is formed, the first overall light distribution is a low beam light distribution (A), the first partial light distribution is a partial high beam light distribution (F), the second overall light distribution is a high beam light distribution (AF), and the second partial light distribution (Z) lies entirely below the hh line (hh) and is bounded by at least one horizontal section of the light/dark boundary (10) of the low beam light distribution (A) at the top and at least partially overlaps the high beam light distribution (AF), and the partial high beam light distribution (F) is formed from one or more segments (30) and has a lower boundary (25), which lower boundary (25) lies at least partially in the low beam light distribution (A), and when the second and third light modules are illuminated at the same time is at least partially overlapped by the second partial light distribution (Z), wherein when all three light modules (105, 106, 107) are illuminated at the same time, a third overall light distribution (AF) is formed.

2. The lighting device according to claim 1, wherein the second overall light distribution (AF) is characterized by a first light intensity profile curve (5) taken along a defined sectional curve (SL).

3. The lighting device according to claim 2, wherein the third overall light distribution (AF) is characterized by a second light intensity profile curve (6) taken along the defined sectional curve (SL).

4. The lighting device according to claim 3, wherein the first light intensity profile curve (5) and the second light intensity profile curve (6) are each at least twice continuously differentiable.

5. The lighting device according to claim 2, wherein the sectional curve (SL) is a straight line.

6. The lighting device according to claim 5, wherein the straight-line sectional curve (SL) runs parallel to the vv line (vv).

7. The lighting device according to claim 2, wherein the minimum radius of curvature (r1), in at least one positive slope region (52, 54) of the first light intensity profile curve (5) in which the light intensity values increase monotonically, and preferably in all positive slope regions, is less than or equal to the minimum radius of curvature (r2) in a positive slope region (62, 64) of the second light intensity profile curve (6) in which the light intensity values increase monotonically, and preferably in all positive slope regions.

8. The lighting device according to claim 2, wherein the minimum radius of curvature in at least one negative slope region (50) of the first light intensity profile curve (5) in which the light intensity values decrease monotonically, and preferably in all negative slope regions, is less than or equal to the minimum radius of curvature in a negative slope region (60) of the second light intensity profile curve (6) in which the light intensity values decrease monotonically, and preferably in all negative slope regions.

9. The lighting device according to claim 1, wherein the third light module (107) is designed and/or arranged in such a manner that it illuminates a horizontally extended strip-shaped segment (Z), wherein the ratio of the segment width to the segment height is at least 2 to 1, and preferably up to 10 to 1.

10. The lighting device according to claim 1, wherein the third light module (107) is designed and/or arranged in such a manner that it illuminates a horizontally extended strip-shaped segment (Z), said segment lying horizontally in a region between about 20 and about +20.

11. The lighting device according to claim 1, wherein the third light module (107) is designed and/or arranged in such a manner that it illuminates a horizontally extended strip-shaped segment (Z), the same lying horizontally in a region between about 20 and about +10, when installed in a vehicle designed for right-hand traffic.

12. The lighting device according to claim 1, wherein the third light module (107) is designed and/or arranged in such a manner that it illuminates a horizontally extended strip-shaped segment (Z), the same lying horizontally in a region between about 10 and about +20, when installed in a vehicle designed for left-hand traffic.

13. The lighting device according to claim 1, wherein the third light module (107) is designed and/or arranged in such a manner that it illuminates a horizontally extended strip-shaped segment, the horizontal extension of which lies in a region from 20 to 40, and preferably is 30.

14. The lighting device according to claim 1, wherein the third light module (107) is designed and/or arranged in such a manner that it illuminates a horizontally extended strip-shaped segment, wherein the same lies vertically in a region between about 4.5 and about 0.

15. The lighting device according to claim 1, wherein the third light module (107) is designed and/or arranged in such a manner that it illuminates a horizontally extended strip-shaped segment with a vertical extension in a region between 0 and 4.5, preferably between 3 and 4.5.

16. The lighting device according to claim 1, wherein the third light module (107) comprises at least one light source and at least one optical head and/or at least one reflector assigned to the at least one light source.

17. The lighting device according to claim 1, wherein the reflector assigned to the third light module (107) is designed as a freeform reflector, for example as a free-form reflector with a parabolic basic shape.

18. The lighting device according to claim 1, wherein the light source arranged in the third light module (107) is designed as a lamp, for example an incandescent lamp according to the ECE-R37 standard, or a standard gas discharge lamp according to the ECE-R99 standard.

19. The lighting device according to claim 1, wherein the light source arranged in the third light module (107) is formed from one, two or more LEDs.

20. The lighting device according to claim 1, wherein the light source arranged in the third light module is designed as a laser light source.

21. The lighting device according to claim 1, wherein the light source arranged in the third light module (107) emits light in a prespecified or prespecifiable spectral range.

22. The lighting device according to claim 1, wherein the light source arranged in the third light module (107) emits light with a color which can be matched to the color of the light emitted from the first light module (105) and/or the second light module (106).

23. The lighting device according to claim 1, wherein the first light module (105), the second light module (106) and the third light module (107) are arranged in a vehicle headlight housing (101).

24. The lighting device according to claim 1, wherein the first light module (105) and the second light module (106) are arranged in a vehicle headlight housing (101), and the third light module (107) is designed as an additional light module (121) and is arranged outside the vehicle headlight housing (101).

25. The lighting device according to claim 1, wherein the segments (30) are rectangular and the lower boundary (25) runs in a straight line.

26. A vehicle headlight having at least one lighting device according to claim 1.

27. A motor vehicle having at least one, preferably two vehicle headlights according to claim 26.

Description

[0046] The present invention is described below in more detail using preferred non-restrictive embodiments, with reference to the drawings, wherein:

[0047] FIG. 1 shows a first overall light distribution,

[0048] FIG. 2 shows a first partial light distribution,

[0049] FIG. 3 shows a second partial light distribution,

[0050] FIG. 4 shows a second overall light distribution,

[0051] FIG. 5 shows a first light intensity profile curve taken along a defined sectional curve,

[0052] FIG. 6 shows a third overall light distribution according to the invention,

[0053] FIG. 7 shows a second light intensity profile curve taken along a defined sectional curve,

[0054] FIG. 8 shows an isolux diagram of the second overall light distribution,

[0055] FIG. 9 shows an isolux diagram of the third overall light distribution,

[0056] FIG. 10 shows a comparison of two light intensity profile curves taken at H=0, with the third light module according to the invention illuminated and without the third light module according to the invention illuminated.

[0057] FIG. 11a shows a gradient profile with the third light module according to the invention illuminated,

[0058] FIG. 11b shows a gradient profile without the third light module according to the invention illuminated,

[0059] FIG. 12 shows a vehicle headlight having light modules arranged within a housing, and

[0060] FIG. 13 shows a vehicle headlight having the third light module arranged outside a housing.

[0061] The following first addresses FIGS. 1-3, which show three basic schematic light distributions. FIG. 1 schematically shows a first typical overall light distribution, in this case in the form of a low beam distribution A which is generated, for example, by means of a light module 105 according to the prior art, as shown in FIGS. 12 and 13. The low beam distribution has a light/dark boundary 10, which has a typical asymmetry in the case shown, for the use of the low beam in right-hand traffic countries.

[0062] FIG. 2 schematically shows a segmented partial light distributionthe partial high beam light distribution F which is formed of rectangular, vertically extended segments 30 and has a lower boundary 25 at which the light intensity of this partial beam distribution has a strong gradient. Such a partial light distribution can be produced, for example, with a known light module 106 according to the prior art, as shown in FIGS. 12 and 13.

[0063] FIG. 3 schematically shows a partial light distribution Z, which is located completely below the hh line and overlaps the low beam distribution A. The partial light distribution Z partially overlaps the lower edge 25 of the partial high beam light distribution F, as shown in FIG. 6.

[0064] FIG. 4 schematically shows a second typical overall light distribution AF, the same being a high beam light distribution, which is produced by the simultaneous illumination of the light modules 105, 106 shown in FIGS. 12 and 13, resulting from the overlap of the low beam distribution A and the partial high beam light distribution F. FIG. 4 also shows a sectional line SL which runs parallel to the ordinate (vv line) vv and intersects the abscissa (hh line) hh at about 2.5.

[0065] FIG. 5 shows a light intensity profile curve 5 which characterizes the second unmodified overall light distribution AF, and which was taken along the sectional curve SL. The light intensity profile curve 5 shows the light intensity values in Candela [cd] when the low beam module 105 and high beam module 106 are illuminated at the same time, as a function of a parameter which is determined by the selection of the sectional curve SL. Because the sectional curve SL in FIG. 4 runs parallel to the vv line, the parameter in FIG. 5 is equal to the angle indicated in degrees on the vv line. The light intensity profile curve 5 in this example of the overall light distribution AF has a rising region which consists of a flat part 54, a steep part 52, and a transition region 55, and also a maximum 53 and a falling region 50. The first flat slope region 54 is characterized by a weak gradient, wherein the second steep rising region 52 has a strong gradient. The shape of the transition region 55 reflects how strongly the gradient function (not shown) changes in this area. The radius of curvature r1 along the transition region 55 serves as a measure of this change.

[0066] FIG. 6 schematically shows a third overall light distribution AF according to the invention, produced by simultaneous illumination of the light modules 105, 106 and 107 shown in FIGS. 12 and 13, resulting from the overlap of the low beam distribution A, the segmented partial high beam light distribution F, and the second partial light distribution Z according to the invention. In addition, FIG. 6 shows a sectional line SL which runs parallel to the vv line and intersects the abscissa (hh line) at, for example, about H=2.5. The arrangement of the second partial light distribution Z according to the invention in FIG. 6 differs from its arrangement in FIG. 3. First, it is quite conceivable that the partial light distribution Z according to the invention is not included in the low beam distribution, and rather partially overlaps the same. On the other hand, the partial light distribution Z, in a preferred embodiment of the invention, can be bounded at the top by the hh line.

[0067] FIG. 7 shows two light intensity profile curves 5, 6 plotted at the same time. The first light intensity profile curve 5 has already been discussed in the description of FIG. 5, and is plotted here with a dashed line to illustrate the differences between the unmodified (second) overall light distribution AF and the modified (third) overall light distribution AF. The second light intensity profile curve 6 (solid line) characterizes the third modified overall light distribution AF, and was taken along the sectional curve SL. The second light intensity profile curve 6 shows the dependence of the light intensity values in Candela [cd] when the low beam module 105, high beam module 106, and the additional module 107 according to the invention are illuminated at the same time, as a function of a parameter which is determined by the selection of the sectional curve SL. Because the sectional curve SL in FIG. 6 runs parallel to the vv line, the parameter in FIG. 7 is equal to the angle in degrees plotted on the vv line. The second light intensity profile curve 6 has, in this example of the overall light distribution AF, a rising region which consists of a flat part 64, a steep part 62, and a transition region 65, and also a maximum 63 and a falling region 60, wherein the falling region 60 of the second light intensity profile curve 6 almost completely matches the falling region 50 of the first light intensity profile curve 5. Here, too, the radius of curvature r2 along the transition zone 65 is a measure of the change in the gradient of the third overall light distribution AF. Because the transition region 65 of the second light intensity profile curve 6 is less curved than the transition region 55 of the first light intensity profile curve 5, the minimum value of the radius of curvature r2 along the transition region 65 is greater than the minimum value of the radius of curvature r1 along the transition region 55. This shows that the transition 65 is softer than the transition 55, and is subjectively more pleasant for the driver.

[0068] FIGS. 8 and 9 show the differences discussed above between the typical unmodified second overall light distribution AF and the third overall light distribution AF modified according to the invention. Both figures illustrate an isolux diagram which corresponds to a corresponding light distribution taken on a measuring screen set up at a certain distance perpendicular to the optical axis of the light modules. Each contourcalled isolux linesdescribes a set of points at which the light intensity is of a certain light intensity value which is the same for all points of this set. The spacing between the contours, measured along a certain section, describes how much the gradient along this section changes. The distance measured in FIG. 8 along the vertical line H=0 (the vv line) between the second K2 and the third K3, as well as between the third K3 and the fourth K4, contours is clearly smaller than the distance measured in FIG. 9 along the vertical line H=0 (the vv line) between the second k2 and the third K3, as well as between the third K3 and the fourth K4 contours, and reflects the reduction of the gradient. For this reason, the overall light distribution AF generated by the third light module according to the invention is perceived as more pleasant by the driver than the typical overall light distribution AF.

[0069] The corresponding light intensity profile curves 5, 6 and the associated gradient functions are shown in FIG. 10 and FIGS. 11a and 11b. The minimum value of the gradient in FIG. 11a is about 0.5 and is greater than the minimum value of the gradient in FIG. 11b, which is about 0.25.

[0070] Various arrangements and configurations of the third light module 107 can be contemplated for generating the second partial light distribution according to the invention. A reflector is preferably assigned to the third light module 107, as shown in FIG. 12 and FIG. 13. It is advantageous to arrange the third light module 107 with the first light module 105 and with the second light module 106 in a vehicle headlight housing 101, as shown in FIG. 12. However, this overall arrangement could, depending on the dimensions of the individual light modules, violate the ECE regulations. Therefore, it can be contemplated that the third light module 107 is arranged outside of the vehicle headlight housing. This arrangement is shown in FIG. 13.

[0071] The invention has been described with the example of a segmented partial high beam light distribution, for which the invention is particularly advantageous because a segmented partial light distribution has a lower edge 25 where the overall high beam light distribution has a particularly strong gradient.

[0072] However, in principle, the invention is also applicable in the context of non-segmented partial high beam light distributions.