Lighting device for a motor vehicle

Abstract

The invention relates to a lighting device (1) for a motor vehicle for generating a lighting function comprising a tail light and / or a brake light. The lighting device (1) according to the invention comprises a light-emitting unit (10) for generating the lighting function, the light-emitting unit (10) being divided into a plurality of segments (11, 12, 13) that extend in a main direction (Y), the light-emitting unit (10) being designed to set the luminance in each of the plurality of segments (11, 12, 13) independently of one another to a predefined value in order to generate a specific lighting function. Furthermore, a control unit is provided for independently adjusting the luminance of the plurality of segments (11, 12, 13), which control unit, when the lighting function to be generated includes the activation of the brake light, is designed to: set a first, high luminance (LUM1) in a first segment (11) of the plurality of segments (11, 12, 13), said first luminance fulfilling the requirements for a brake light; set a second, low luminance (LUM2) in a second segment (12) of the plurality of segments (11, 12, 13), said second luminance fulfilling the requirements for a tail light or corresponding to a deactivated tail light; and set a luminance in a third segment (13) which is arranged along the main direction (Y) between the first segment (11) and the second segment (12) and is adjacent thereto, in particular without interruption, said luminance in the third segment decreasing according to a predefined gradient function from the first luminance (LUM1) of the first segment (11) to the second luminance (LUM2) of the second segment (12).

Description

[0001] LIGHTING DEVICE FOR A MOTOR VEHICLE

[0002] The invention relates to a lighting device for a motor vehicle for generating a lighting function that detects a tail light and / or a brake light.

[0003] Such a lighting device comprises a light-emitting unit for generating the lighting function. Typically, the light-emitting unit is divided into several segments, with the light-emitting unit being configured to independently adjust the luminance in each of the several segments to a predetermined value in order to generate a specific lighting function.

[0004] There is a desire to have all lighting functions of the lighting device, such as the tail light, brake light, and indicators, illuminate the center of the vehicle. The "center of the vehicle" is defined as the center of the vehicle in the longitudinal direction. However, under current legal regulations, such a lighting device cannot be implemented, as the brake light must end 300 mm from the center of the vehicle in the transverse direction.

[0005] If the tail light and brake light are implemented using the same surface of the light-emitting unit, jumps in luminance and changes in the luminance gradient will occur due to high contrast. This is undesirable for design reasons and also results in limited visibility during braking. To prevent these undesirable effects, it is known to implement a shared tail light and brake light in a single lighting device using geometrically identical functions, i.e., surfaces of equal size. Alternatively, it is known to implement a brake light with a smaller surface area, thereby accepting an abrupt transition from light to dark.

[0006] It is an object of the invention to provide a technically and functionally improved lighting device for a motor vehicle for generating a lighting function which comprises a tail light and / or a brake light.

[0007] This object is achieved by a lighting device according to the features of claim 1. Advantageous embodiments emerge from the dependent claims. A lighting device for a motor vehicle is proposed for generating a lighting function, which comprises a tail light and / or a brake light. In particular, the lighting device is a rear light of the motor vehicle.

[0008] The lighting device comprises a light emitting unit and a control unit.

[0009] The light-emitting unit serves to generate the lighting function, wherein the light-emitting unit is divided into several segments extending in a main direction. The light-emitting unit is designed to independently adjust the luminance in each of the several segments to a predetermined value in order to generate a specific lighting function. The luminance can be adjusted, for example, by controlling a number of light sources (e.g., light-emitting diodes (LEDs)) or the luminous flux emitted by at least one light source.

[0010] The control unit serves to independently adjust the luminance of the plurality of segments, wherein the control unit, if the light function to be generated comprises the activation of the brake light, is designed to set a first, high luminance in a first segment of the plurality of segments, which meets the requirements for a brake light, and to set a second, low luminance in a second segment of the plurality of segments, which meets the requirements for a tail light or which corresponds to a deactivated tail light, and to set a luminance in a third segment, which is arranged along the main direction between the first segment and the second segment and borders on them, in particular without interruption, which decreases according to a predetermined gradient function from the first luminance of the first segment to the second luminance of the second segment.

[0011] The invention thus provides a lighting device in which the tail light occupies a larger area than the brake light. The lighting device is not only aesthetically pleasing but also realizes a clearly perceptible brake light function by approximating the luminance of the brake light in a main direction of the lighting device to the luminance of the tail light. This prevents abrupt jumps in luminance.

[0012] The human eye thus perceives a smooth transition from a very high luminance (the bright red of the brake light) to a lower luminance (the comparatively darker red of the tail light). In particular, this makes it possible to extend the lighting device to the center of the vehicle. At the same time, it complies with the legal regulations that the brake light may not extend to the center of the vehicle, but must end 300 mm before reaching the center of the vehicle.

[0013] In a practical embodiment, the multiple segments extend one behind the other in a main direction. In particular, the main direction runs in the direction of a vehicle's transverse axis, allowing the just-described lighting device, which extends from the vehicle's outer side to the center, to be realized. Alternatively, the main direction can also run in the direction of a vehicle's vertical axis. Other main directions are also conceivable.

[0014] According to a further advantageous embodiment, the surface of the first segment has an area that corresponds to at least one brake light area according to legal requirements. The legally prescribed brake light area can vary from country to country. This ensures that at least one area that meets the legal requirements is illuminated for the brake light function in every case.

[0015] It is also expedient if the predefined gradient function decreases linearly along the main direction from the first luminance to the second luminance. Alternatively, it can be provided that the predefined gradient function decreases nonlinearly along the main direction from the first luminance to the second luminance. The predefined gradient function can, in principle, be configured as desired, as long as it is ensured that it decreases from the first luminance of the first segment to the second luminance of the second segment. For example, the predefined gradient function can be composed of several combined linear luminance gradients.

[0016] A further expedient embodiment provides that the luminance is adjusted by at least one of the following methods: pulse width modulation;

[0017] Current modulation; number of controlled light sources; type of controlled light sources; diffusion optics; lens; software binning (i.e. identification of the so-called binning (classification / accuracy) of an LED via software in order to be able to achieve the desired color location when controlling the LED).

[0018] According to another advantageous embodiment, the control unit never activates the second segment as a brake light. This allows the second segment to be extended to the center of the vehicle, allowing lighting functions such as tail lights or daytime running lights to illuminate the center.

[0019] A further expedient embodiment provides that the first segment is divided into a first and a second sub-segment, wherein the first sub-segment is arranged in a vehicle body and the second sub-segment is arranged in a hood or lid of the motor vehicle. The first sub-segment can, for example, have a surface that corresponds to the legally prescribed brake light surface. The legally prescribed brake light surface can also be formed by the first and the second sub-segment. This embodiment makes it possible to implement in particular the brake light, but also the tail light and an indicator, e.g. in one part of the vehicle body and one part of the trunk.

[0020] The invention is described in more detail below using an exemplary embodiment in the figures. They show:

[0021] Fig. 1 is a schematic representation of a lighting device according to the invention with several segments arranged one behind the other in a main direction;

[0022] Fig. 2 is a diagram showing the luminance curve in the segments of the lighting device with the tail light deactivated and the brake light activated;

[0023] Fig. 3 is a schematic representation of the segments of the lighting device from Fig. 1 , in which the luminance is shown once with the tail light deactivated and once with the brake light activated;

[0024] Fig. 4 is a diagram showing the luminance curve in the segments of the lighting device according to Fig. 1 with the tail light and brake light activated;

[0025] Fig. 5 is a schematic representation of the segments of the lighting device from Fig. 1 , in which the luminance is shown once with the tail light activated and once with the brake light activated;

[0026] Fig. 6 is a schematic representation of a further lighting device according to the invention, in which the segment intended to generate the brake light function is divided into a first and a second sub-segment; and

[0027] Fig. 7 is a partial rear view of a motor vehicle with a lighting device, in which the segments of the lighting device described above are illustrated by way of example.

[0028] Fig. 1 shows a schematic representation of a lighting device 1 according to the invention. The lighting device 1 represents a rear light of a motor vehicle (not shown in detail). The lighting device 1 comprises a light-emitting unit 10 for generating a lighting function that includes a tail light and / or a brake light. The light-emitting unit 10 comprises, for example, three segments 11, 12, 13 that extend one behind the other in a main direction Y. For example, the main direction Y corresponds to a vehicle transverse axis direction FQR. It can also correspond to a vehicle vertical axis direction FHR.

[0029] Each segment 11, 12, 13 of the light-emitting unit is assigned at least one light source (not shown). The at least one light source can be in the form of a light-emitting diode (LED), for example. The light sources of the segments 11, 12, 13 can be of the same or different types. Each segment 11, 12, 13 can be assigned the same number of light sources or a different number of light sources. The control of the light sources to emit light occurs in a manner known to those skilled in the art, so this will not be explained in detail here.

[0030] Each of the segments 11, 12, 13 may further comprise a diffusing optic and / or lens to enable light emission in a desired direction and intensity. Since this is not important for understanding the present invention, it will not be discussed in further detail below.

[0031] In general, the light emission unit 10 is designed to set the luminance in each of the plurality of segments 11, 12, 13 independently of one another to a predetermined value. The predetermined value depends on which lighting function is to be generated. As explained, the lighting function comprises a tail light and / or a brake light. Other lighting functions that can be generated include, for example, a reversing light, a turn signal, or daytime running light, although this is not relevant for the present invention. The independent adjustment of the luminance of the plurality of segments 11, 12, 13 is carried out by a control unit (not shown). If the lighting function to be generated comprises the activation of the brake light, the control unit is designed to set a first, high luminance LUM1 in a first segment of the plurality of segments, which meets the requirements of a brake light.The control unit is further configured to set a low, second luminance LUM2 in the second segment 12 of the plurality of segments, which meets the requirements for a tail light or corresponds to a deactivated tail light. Finally, the control unit is configured to set a luminance in the third segment 13, which is arranged along the main direction Y between the first segment 11 and the second segment 12 and borders them, in particular without interruption, which decreases according to a predetermined gradient function from the first luminance LUM1 of the first segment 11 to the second luminance LUM2 of the second segment 12.

[0032] In the illustration shown, the first segment 11 of the light emission unit 10 borders, for example, a left-hand body component of a vehicle viewed from the rear, while the second segment 12 faces the center of the motor vehicle. The first segment 11 has a length L11 in the vehicle's transverse axis direction FQR or in the main direction Y, which, in conjunction with its height, meets the requirements for a legally prescribed brake light surface.

[0033] The total length L10 of the light-emitting unit 10 can, for example, correspond to half the vehicle width of the motor vehicle. In this case, the second segment 12 and the third segment 13 would provide a lighting function extending to the center of the vehicle. It is understood that the total length L10 can also be less than half the vehicle width of the motor vehicle.

[0034] Through the described control of the light sources of the light emission unit 10, the luminance of the brake light in the first segment 11 in the main direction Y is brought closer to the luminance of the second segment 12, which either corresponds to the luminance of the tail light or is 0. In other words, in the third segment 13, a luminance drop occurs from the first luminance LUM1 toward the second luminance LUM2. This avoids abrupt jumps in luminance. The human eye thus perceives a smooth transition.

[0035] The luminance drop in the third segment 13 can be achieved through pulse width modulation, current modulation, a change in the number of controlled light sources in the third segment 13, a targeted control of the type of light sources in the third segment 13, or the activation of a scattering optic and / or lens. So-called software binning is also possible.

[0036] Fig. 2 shows a diagram showing the luminance curve in the segments 11 to 13 of the lighting device 1 when the tail light is deactivated (dash-dotted line) and when the brake light is activated with the tail light deactivated (solid line).

[0037] When the tail light is deactivated, the control unit generates the second luminance LUM2, i.e. 0, in each of the segments 11, 12, 13. In Fig. 3, this scenario is shown in the upper half with “tail light off”. If the brake light function is generated with the tail light deactivated, the first luminance LUM1 is generated in the first segment 11, as shown in Fig. 2. In the third segment 13, the luminance drops linearly from the first luminance LUM1 to the second luminance LUM2 (0), for example. In Fig. 3, this scenario is shown in the lower half with “brake light without tail light”.

[0038] It is clearly visible that the first segment 11 has a dark gray shade, corresponding to the high, first luminance LUM1. The gray shade decreases from the end of the third segment 13, which borders the first segment 11, toward the second segment 12, toward a light color (white). This results in the desired smooth transition from a very bright red brake light to a deactivated tail light.

[0039] Fig. 4 shows a diagram with a luminance curve in the segments 11 to 13 of the lighting device 1 when the tail light is activated (dash-dotted line) and when the brake light is activated with the tail light activated (solid line).

[0040] When the tail light is activated, the control unit generates the second luminance LUM2, which is greater than 0, in each of the segments 11, 12, 13. In Fig. 5, this scenario is shown in the upper half with “tail light on,” with segments 11, 12, 13 having a light gray shading. The light gray shading represents the second, low luminance LUM2 (which is greater than 0). If the brake light function is generated when the tail light is activated, the luminance LUM1 is generated in the first segment 11, as shown in Fig. 5. In the third segment 13, the luminance drops from the first luminance LUM1 to the second luminance LUM2, again purely linearly by way of example. In Fig. 5, this scenario is shown in the lower half with “brake light with tail light.” It can be seen again that the first segment 11 has a dark grey shade, which corresponds to the high, first luminance LUM1.The gray shade decreases from the end of the third segment 13, which borders the first segment 11, toward the second segment 12, toward the light gray shade corresponding to the second luminance LUM2. This also results in the desired smooth transition from a very bright red of the brake light to a dark red of the activated tail light.

[0041] Fig. 6 shows a further embodiment of an inventive

[0042] Lighting device 1, in which the first segment 11 of the light-emitting unit 10 is divided into a first sub-segment 11-1 and a second sub-segment 11-2. For example, the first sub-segment 11-1 is arranged in a vehicle body, and the second sub-segment 11-2 is arranged in a hood or flap (e.g., trunk) of the motor vehicle. Such a division can be seen, for example, in the partial rear view of the motor vehicle shown in Fig. 7, in which the various segments 11-1, 11-2, 12, 13 of the light-emitting unit 10 are labeled.

[0043] List of reference symbols

[0044] I Lighting device

[0045] 10 Light emission unit

[0046] II first segment

[0047] 11-1 first sub-segment

[0048] 11-2 second sub-segment

[0049] 12 second segment

[0050] 13 third segment

[0051] 10A first outer end of the lighting device

[0052] 101 second, inner end of the lighting device

[0053] L11 Length of the first segment 11

[0054] L10 total length of the light emitting unit

[0055] LUM1 first luminance

[0056] LU M2 second luminance

Claims

Patent claims 1. A lighting device (1) for a motor vehicle for generating a lighting function comprising a tail light and / or a brake light, comprising a light-emitting unit (10) for generating the lighting function, wherein the light-emitting unit (10) is divided into a plurality of segments (11, 12, 13) extending in a main direction (Y), wherein the light-emitting unit (10) is configured to set the luminance in each of the plurality of segments (11, 12, 13) independently of one another to a predetermined value in order to generate a specific lighting function; a control unit for independently adjusting the luminance of the plurality of segments (11, 12, 13), which, when the lighting function to be generated comprises the activation of the brake light, is configured to set a first, high luminance (LUM1) in a first segment (11) of the plurality of segments (11, 12, 13) that meets the requirements for a brake light,and in a second segment (12) of the plurality of segments (11, 12, 13), to set a second, low luminance (LUM2) which meets the requirements for a tail light or which corresponds to a deactivated tail light, and in a third segment (13), which is arranged along the main direction (Y) between the first segment (11) and the second segment (12) and adjoins them, in particular without interruption, to set a luminance which decreases according to a predetermined gradient function from the first luminance (LUM1) of the first segment (11) to the second luminance (LUM2) of the second segment (12).

2. Lighting device (1) according to claim 1, wherein the plurality of segments (11, 12, 13) extend one behind the other in a main direction (Y).

3. Lighting device (1) according to claim 1 or 2, wherein the main direction (Y) runs in the direction of a vehicle transverse axis or in the direction of a vehicle vertical axis.

4. Lighting device (1) according to one of the preceding claims, wherein the lighting device is a rear light of the motor vehicle.

5. Lighting device (1) according to one of the preceding claims, wherein the surface of the first segment (11) has a surface which corresponds to at least one brake light surface according to legal requirements.

6. Lighting device (1) according to one of claims 1 to 5, wherein the predetermined progression function decreases linearly along the main direction (Y) from the first luminance (LUM1) to the second luminance (LUM2).

7. Lighting device (1) according to one of claims 1 to 5, wherein the predetermined progression function decreases non-linearly along the main direction (Y) from the first luminance (LUM1) to the second luminance (LUM2).

8. Lighting device (1) according to one of the preceding claims, wherein the adjustment of the luminance is carried out by at least one of the following methods: Pulse width modulation; current modulation; Software binning; Number of controlled light sources; Type of controlled light sources; Diffusing optics; Lens.

9. Lighting device (1) according to one of the preceding claims, wherein the second segment (12) is not controlled as a brake light by the control unit at any time.

10. Lighting device (1) according to one of the preceding claims, wherein the first segment (11) is divided into a first and a second sub-segment, wherein the first sub-segment (11-1) is arranged in a vehicle body and the second sub-segment (11-2) is arranged in a hood or flap of the motor vehicle.

Images