Lighting device for a motor vehicle, in particular a high-resolution headlamp

Abstract

The invention relates to a lighting device having a light emitting diode array comprising an adjustable current source for each LED, which provides a pulse width modulated current with a pulse height, a control / regulation device for controlling / regulating the brightness of the individual LEDs, which can generate a theoretical value for the pulse height for the current source, and the brightness value can be set for each LED in accordance with the theoretical value and can be encoded in a video signal and can be provided on a video signal output, the light emitting diode array having a video signal input, the light emitting diode array having a decoding device connected to the video signal input, with which the brightness value can be decoded from the video signal and can be converted into a duty cycle, with which the pulse height can be generated, the theoretical value for the pulse height likewise being encoded in the video signal or decoded from the video signal and can be used by the current source for adjusting the current height.

Description

Technical Field

[0001] This invention relates to a lighting device for motor vehicles, particularly a high-resolution headlight, the lighting device comprising: an array of light-emitting diodes including n LEDs and each LED including an adjustable current source, wherein each adjustable current source provides a pulse width modulation current having a pulse height for powering the configured LED; and control and / or regulating devices for controlling and / or regulating the brightness of each LED in the light-emitting diode array, wherein the control and / or regulating devices can generate and provide at least a theoretical value of the pulse height for the pulse width modulation current for each adjustable current source, and the control and / or regulating devices can adjust the brightness of each LED according to the pulse height of the adjustable current source configured for the LED. The system theoretically sets a brightness value and can encode the brightness value in a video signal and provide the brightness value at a video signal output terminal. The LED array has a video signal input terminal connected to the video signal output terminal of a control and / or adjustment device. The LED array also has a decoding device connected to the video signal input terminal. Using the decoding device, a brightness value can be decoded from the video signal for each LED, and the brightness value can be converted into a duty cycle. Using this duty cycle, an adjustable current source configured for the LED can generate a pulse width modulation current with a pulse height according to a theoretical value predetermined by the control and / or adjustment device for the current source. Background Technology

[0002] In modern motor vehicles, it is important to use lighting equipment, such as headlights, that can achieve a desired or predetermined light distribution.

[0003] Therefore, it is necessary to use a sufficiently strong light source, which can fully achieve the desired light distribution. However, the desired light distribution depends not only on the strength of the light source. It is also important that the light source can have different brightness values ​​in different areas. For this purpose, it has recently proven advantageous to use light-emitting diodes (LEDs) arranged in a large number as an LED array. However, a problem may still exist here: the LEDs in the LED array do not automatically provide the desired light distribution. Correspondingly, the brightness value is adapted to the desired light distribution in the area of ​​the surface to be illuminated. Therefore, it is necessary to reduce or dim the brightness value of the LEDs. The desired brightness value of the LEDs can be transmitted to the LED array, for example, via a video signal.

[0004] One method to influence the brightness value of a light-emitting diode (LED) is pulse width modulation (PWM), in which the brightness value is adapted by pulsedly turning the LED on and off within a pulse cycle. This is typically implemented with the pulse height of the current remaining constant.

[0005] The disadvantage of the described approach is that the power loss regarding the brightness value emitted by the LED is relatively high. Lower power loss can be achieved while maintaining a constant brightness value by reducing the pulse height of the current and increasing the duty cycle within one pulse period. In modern lighting equipment, it is not possible to change the pulse height while simultaneously changing the duty cycle, as this would result in a time difference between the pulse height used for the current and the brightness value. The signal is transmitted to each current source through different channels. The theoretical value for the pulse height is provided directly to the current source by control and / or regulation devices. The duty cycle, as the brightness value, is transmitted in the video signal that must be decoded. This time difference in the signal's operation results in a short-term change in the desired light distribution. Summary of the Invention

[0006] This invention begins here.

[0007] The objective of this invention is to provide a lighting device and a method for motor vehicles, which minimizes or completely eliminates the time difference of a signal.

[0008] The task is solved according to the present invention in the following manner: the theoretical value of the pulse height for the current can also be encoded in the video signal by the control and / or adjustment device and can also be decoded from the video signal by the decoding device and can be used by the current source to adjust the height of the current, that is, the pulse height of the pulse width modulated current.

[0009] By using the video signal to transmit not only the brightness value of each LED but also the pulse height of the current, both signals exist precisely and simultaneously at the video signal input of the LED array and can be processed by a decoding device. The signals are synchronized through image-like transmission within the video signal. This allows for the adaptation of the current pulse height and simultaneously the duty cycle determined by the brightness value. In this approach, the light distribution of the lighting device can still be achieved as desired despite changes in duty cycle and pulse height. An observer viewing the light distribution of the lighting device from the outside will not perceive the adaptation of the current pulse height and duty cycle. In particular, completely short-duration changes in illumination are avoided, which would appear as flickering to the observer.

[0010] It can be specified that the video signal is an RGB signal. When using the video signal to transmit luminance values, the luminance values ​​are encoded in the useful area of ​​the video signal. It is possible that the theoretical value of the pulse height used for the current is encoded in the non-useful area, i.e., the blank area, of the video signal.

[0011] Furthermore, it can be specified that the adjustable current sources operate according to a master-slave principle, wherein at least one of the adjustable current sources serves as the master, predetermining the pulse height and current duty cycle and transmitting it to the remaining adjustable current sources.

[0012] It can be stipulated that the motor vehicle is constructed to have a lighting device according to the present invention.

[0013] It can be specified that the method for operating the lighting device for a motor vehicle according to the present invention includes at least the following steps:

[0014] The control and / or regulation device generates at least a theoretical value for the pulse height of the pulse width modulation current for each adjustable current source configured for the LED, provides the theoretical value, and sets a brightness value for each LED based on the theoretical value for the pulse height.

[0015] The control and / or regulation device encodes the theoretical value of the pulse height for the pulse width modulation current and the brightness value for each LED into a video signal and provides the video signal at the video signal output.

[0016] - The device used for decoding is connected to the video signal input of the LED array and decodes the brightness value from the video signal for each LED and converts the brightness value into a duty cycle.

[0017] - The device used for decoding decodes the theoretical value of the pulse height for the current, and

[0018] - The adjustable current source uses the theoretical value to adjust the height of the current, that is, the pulse height of the pulse width modulated current.

[0019] There is a possibility that the theoretical value of the pulse height for the pulse width modulation current can be changed in the same way as the duty cycle time, while keeping the brightness value of each LED in the light-emitting diode array constant. Attached Figure Description

[0020] The invention will now be described in more detail with the aid of the accompanying drawings. In the drawings:

[0021] Figure 1 A schematic construction of a lighting device according to the present invention is shown.

[0022] Figure 2 A schematic construction of a single video image of a video signal is shown. Detailed Implementation

[0023] exist Figure 1 The lighting device 1 according to the invention shown includes a light-emitting diode array 2 comprising five series circuits. Each series circuit includes a light-emitting diode 3 and an adjustable current source 4. Each adjustable current source 4 provides a pulse-width modulated current to power the configured LED 3, the pulse-width modulated current having a pulse height. The series circuits are connected in parallel. Furthermore, the light-emitting diode array 2 includes a decoding device 8, the decoding device being connected at its output to each adjustable current source 4.

[0024] In addition to the LED array 2, the lighting device 1 includes a control and / or adjustment device 5. The control and / or adjustment device 5 is connected to the video signal input terminal 7 of the LED array via a video output terminal 6 and to a device 8 for decoding.

[0025] The control and / or adjustment device 5 generates a theoretical value 22 for the pulse height of the pulse width modulation current for each adjustable current source 4. Furthermore, the control and / or adjustment device 5 sets a brightness value for each LED 3 based on the theoretical value 22 of the pulse height configured for each adjustable current source 4. Not only the theoretical value 22 for the pulse height of the current but also the brightness value for each LED 3 is encoded in a video signal and provided at the video signal output terminal 6 of the control and / or adjustment device 5.

[0026] The decoding device 8 decodes the brightness value of each LED 3 from the video signal and converts the brightness value into a duty cycle. Similarly, the theoretical value 22 of the pulse height for the current is used by the decoding device 8 to decode from the video signal. The theoretical value 22 of not only the duty cycle but also the pulse height for the current is provided at the output of the decoding device and is used by an adjustable current source 4 to adjust the height of the current, i.e., the pulse height of the pulse width modulated current, which powers the respective LEDs 3.

[0027] Figure 2 A schematic configuration of a single video image 9 of the video signal used is shown, which is used to transmit the theoretical value 22 of the pulse height for current to the light-emitting diode array 2.

[0028] The video image 9 has a total height 10 and a total width 11. The total height 10 is divided into four regions 13, 15, 17, and 19. The first region is referred to as the effective height 13. In the lower region of the image, the vertical leading edge 19 is adjacent to the first region, and in the upper region of the image, the vertical trailing edge 17 is adjacent to the first region. Furthermore, the vertically synchronized region 15 is adjacent to the vertical trailing edge 17.

[0029] The total width 11 can also be divided into four regions 12, 14, 16, and 18. The first region, called the effective width 12, is surrounded by the horizontal leading edge 18 in the right part of the image and by the horizontal trailing edge 16 in the left part of the image. The horizontally synchronized region 14 is adjacent to the horizontal trailing edge 16.

[0030] Useful information of the video signal is transmitted in an area defined by an effective height of 10 and an effective width of 11. This area can be divided into a first video portion image 20 and a second video portion image 21. Each video portion image 20, 21 encodes the brightness value of each LED 3 in 16383 pixels.

[0031] Outside the area defined by the effective height 10 and effective width 11, there exists a non-useful area for the video image, i.e., a blank area. The vertical trailing edge 17 also belongs to this blank area, in which the theoretical value 22 of the pulse height for transmitting current is transmitted.

[0032] List of reference numerals

[0033] 1 Lighting equipment

[0034] 2 LED array

[0035] 3 LEDs

[0036] 4 Adjustable current source

[0037] 5. Control and / or regulation devices

[0038] 6 Video signal output terminals

[0039] 7 Video signal input terminals

[0040] 8 Devices used for decoding

[0041] 9 video images

[0042] 10 Total height

[0043] 11 Total Width

[0044] 12 Effective Height

[0045] 13 Effective width

[0046] 14 Horizontally synchronized areas

[0047] 15 Vertically synchronized areas

[0048] 16 Horizontal trailing edge

[0049] 17. Vertical rear edge

[0050] 18 Horizontal Frontier

[0051] 19 Vertical frontier

[0052] 20 First video portion images

[0053] 21 Second video section images

[0054] 22 Theoretical value

Claims

1. A lighting device (1) for a motor vehicle, said lighting device having An array of light-emitting diodes (2) comprising n LEDs (3) and an adjustable current source (4) for each LED (3). Each adjustable current source (4) provides a pulse width modulated current with pulse height for powering the configured LED (3). Control and / or adjustment device (5) for controlling and / or adjusting the brightness of each LED (3) in the light-emitting diode array (2), The control and / or regulation device (5) is capable of generating and providing a theoretical value (22) for the pulse height of the pulse width modulation current at least for each adjustable current source (4), and Using the control and / or adjustment device (5), the brightness value for each LED (3) can be set according to the theoretical value (22) of the pulse height of the adjustable current source (4) configured for the LED (3), and the brightness value can be encoded in the video signal and provided on the video signal output terminal (6). The light-emitting diode array (2) has a video signal input terminal (7), which is connected to the video signal output terminal (6) of the control and / or adjustment device (5), and The light-emitting diode array (2) has a decoding device (8) connected to a video signal input terminal (7). The decoding device can decode the brightness value from the video signal for each LED (3) and convert the brightness value into a duty cycle. Using this duty cycle, an adjustable current source (4) configured for the LED (3) can generate a pulse-width modulated current with a pulse height according to a predetermined theoretical value (22) for the current source via a control and / or adjustment device (5). Its features are, The theoretical value (22) of the pulse height for the current can also be encoded in the video signal by the control and / or adjustment device (5) and can also be decoded from the video signal by the decoding device (8), and the theoretical value can be used by the adjustable current source (4) to adjust the height of the current, that is, the pulse height of the pulse width modulated current. In this context, it is possible that the theoretical value (22) of the pulse height for the pulse width modulation current changes in the same way as the duty cycle, while keeping the brightness value of each LED (3) in the light-emitting diode array (2) constant.

2. The lighting device (1) for a motor vehicle according to claim 1, characterized in that, The video signal is an RGB signal.

3. The lighting device (1) for a motor vehicle according to claim 1 or 2, characterized in that, The theoretical value (22) of the pulse height used for current is encoded in the area of ​​the video signal that is not used for brightness value, i.e., the blank area.

4. The lighting device (1) for a motor vehicle according to claim 1 or 2, characterized in that, The adjustable current source (4) operates according to the master-slave principle, wherein at least one of the adjustable current sources (4) serves as the pulse height of the master predetermined current and transmits the pulse height of the current to the other adjustable current sources (4).

5. The lighting device (1) for a motor vehicle according to claim 1 or 2, characterized in that, The lighting equipment used for motor vehicles (1) is a high-resolution headlight.

6. A motor vehicle having a lighting device (1) for a motor vehicle as described in any one of claims 1 to 5.

7. A method for operating a lighting device (1) for a motor vehicle according to any one of claims 1 to 5, The method comprises at least the following steps: The control and / or regulating device (5) generates a theoretical value (22) for the pulse height of the pulse width modulation current for at least each adjustable current source (4) configured for the LED (3) and provides the theoretical value and sets a brightness value for each LED (3) based on the theoretical value (22) for the pulse height. The control and / or regulation device (5) encodes the theoretical value (22) of the pulse height for the pulse width modulation current and the brightness value for each LED (3) in a video signal and provides the video signal at the video signal output terminal (6). The decoding device (8) is connected to the video signal input terminal (7) of the LED array (2) and decodes the brightness value for each LED (3) from the video signal and converts the brightness value into a duty cycle. The device (8) used for decoding decodes the theoretical value (22) of the pulse height for the current, and The adjustable current source (4) uses the theoretical value to adjust the height of the current, that is, the pulse height of the pulse width modulated current. Its features are, With the brightness value of each LED (3) in the light-emitting diode array (2) remaining constant, it is possible for the theoretical value (22) of the pulse height for the pulse width modulation current to change in the same way as the duty cycle over time.

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