Headlights and methods for operating a headlight

Abstract

Headlights (1) for a vehicle with - a plurality of multiple pixel light sources (2.1, 2.2) and - at least one electronic control unit (8) for controlling the pixel light sources (2.1, 2.2), wherein - the control unit (8) includes or is coupled to at least one data transmission interface (9) with a plurality of data transmission channels (9.1, 9.2) and - each data transmission channel (9.1, 9.2) is assigned a maximum of one pixel light source (2.1, 2.2), characterized in that - the majority of the data transmission channels (9.1, 9.2) are bundled into at least one communication channel (9.3) and - a selection circuit (9.4) is arranged between the communication channel (9.3) and the pixel light sources (2.1, 2.2) for switching control signals transmitted via the communication channel (9.3) to the pixel light sources (2.1, 2.2) and - the data transmission interface (9) is a video interface.

Description

[0001] The invention relates to a headlight for a vehicle according to the preamble of claim 1.

[0002] The invention further relates to a method for operating a headlight for a vehicle according to the preamble of claim 6.

[0003] Pixel light sources within the meaning of this invention are all pixelated light sources, regardless of the technology from which the individual pixels are composed. In particular, the term pixel light source within the meaning of the invention includes LED arrays, LED arrays, LCD displays, or digital light processing (DLP) chips, in which the light from a light source is directed onto a chip that reflects it with up to 2 million micromirrors.

[0004] From DE 10 2012 008 833 A1, a headlight for a vehicle with a lighting arrangement is known. The lighting arrangement comprises a number of light-emitting diodes, which are grouped together in a number of light-emitting diode arrays.

[0005] Furthermore, DE 10 2007 050 374 A1 discloses a vehicle headlight with an optical imaging device, wherein the imaging device has at least one freeform surface for optical imaging. The vehicle headlight comprises at least one array of light-emitting diodes as a light source, wherein the light-emitting diodes of the array can be individually controlled by means of an electronic control unit. A number of lighting patterns of the array can be stored in the control unit, and one of these lighting patterns can be selected by means of the control unit. The array of light-emitting diodes can be controlled according to the selected lighting pattern, whereby each lighting pattern determines the number of light-emitting diodes to be switched on, their arrangement, and their respective brightness. A method for operating a vehicle headlight is also described.

[0006] From "Schneider, D.: Marker light - a headlight light distribution for attention control and perception enhancement of vehicle drivers; Munich: Utz, 2011 (Darmstadt Lighting Technology); ISBN: 978-3-38316-4116-1!" a headlight with a large number of light-emitting diodes arranged in a so-called array is known. A circuit is provided for controlling the light-emitting diode array, which uses an I 2 C-Buses can be connected to microcontrollers, i.e., to control units. In this process, a control unit addresses an I 2 C-Bus uses two drivers, each of which controls a 16-LED array using pulse width modulation.

[0007] Furthermore, headlights for vehicles and methods for operating such headlights are known from DE 10 2012 008 833 A1, DE 10 2005 041 792 A1, DE 10 2013 016 904 A1 and DE 10 2007 050 374 A1.

[0008] Furthermore, DE 10 2008 062 640 A1 describes a control method for a vehicle headlight and a vehicle headlight with a plurality of LED light sources combined in a common light-emitting light source matrix, wherein the individual LED light sources are switchable, switchable off, and dimmable in order to change the light distribution of the light-emitting light source matrix. A storage unit is provided in which a light distribution is stored as a brightness value for each individual LED light source. An evaluation and control unit selects a stored light distribution depending on a received parameter and controls the LED light sources of the light source matrix accordingly to adjust the selected light distribution. The selection of the light distribution displayed by the light source matrix is ​​carried out via a CAN bus message.

[0009] Furthermore, the following are known to be state of the art: Texas Instruments "TPS92661 EVM-001 LED Matrix Manager Evaluation Module (EVM) User's Guide", September 2014 and Texas Instruments datasheet TPS92661-QI “High-Brightness LED Matrix Manager for Automotive Headlight Systems”, September 2014.

[0010] The invention is based on the objective of providing a headlight for a vehicle that is improved compared to the prior art, and an improved method for operating a headlight for a vehicle.

[0011] With regard to the headlight, the problem is solved according to the invention by the features specified in claim 1 and with regard to the method by the features specified in claim 6.

[0012] Advantageous embodiments of the invention are the subject of the dependent claims.

[0013] A vehicle headlight comprises multiple light sources, the light distribution of which is composed of individual light sources (pixel light sources), and at least one electronic control unit for controlling the pixel light sources. This control unit includes, or is coupled to, at least one data transmission interface, in particular a high-speed data transmission interface, with multiple data transmission channels, each data transmission channel being assigned to a maximum of one pixel light source. This makes it particularly advantageous to control multiple pixel light sources, also known as LED arrays, LED arrays, or simply LED arrays, using a single control unit. In contrast to solutions where a separate control unit is provided for each pixel light source, this results in significant savings in material, cost, and weight.

[0014] According to the invention, the majority of the data transmission channels are bundled into at least one communication channel. This enables simplified conductor routing from the control unit to the pixel light sources.

[0015] To optimize this bundling, a selection circuit is arranged between the communication channel and the pixel light sources to switch control signals transmitted via the communication channel to the pixel light sources.

[0016] According to a possible further development of the headlight, a pixel light source is assigned to several bundled data transmission channels. This bundling achieves a higher possible data transmission rate, thereby realizing a higher resolution of the light distribution generated by the corresponding pixel light source and / or a higher dynamic range when the light distribution changes.

[0017] In a further development of the headlight, the communication channel is a low-voltage differential signaling channel. This design enables the simple implementation of high-speed data transmission with low voltage levels and a particularly simple architecture.

[0018] According to an embodiment of the headlight according to the invention, the data transmission interface is a video interface, which is characterized by a high level of maturity and high availability with a simple and cost-effective design.

[0019] According to one possible configuration, the data transmission interface comprises several, in particular three, data transmission channels configured as color channels, forming a so-called RGB interface (R = Red, G = Green, B = Blue), which can be implemented with minimal material and cost expenditure. For example, each color channel is configured to transmit at least one grayscale image as a control signal for generating a light distribution to the respective pixel light source. Using such grayscale images, the pixel light sources can be controlled reliably and with minimal data transmission and processing effort. Furthermore, with such a data transmission interface, at least three pixel light sources can be controlled with just one control unit.

[0020] In the method for operating a headlight for a vehicle, a plurality of pixel light sources are controlled by at least one electronic control unit. Control signals are transmitted from the control unit to the pixel light sources via a data transmission interface designed as a video interface according to the invention. The control signals are transmitted to each pixel light source separately via at least one data transmission channel of the data transmission interface assigned to the respective pixel light source. According to the invention, control signals transmitted via the communication channel are switched to the pixel light sources by means of a selection circuit arranged between a communication channel (bundled from the plurality of data transmission channels) and the pixel light sources. The method enables several pixel light sources to be controlled by a common control unit.In contrast to solutions where a separate control unit is provided for each pixel light source, this results in significant savings in material, costs and weight.

[0021] According to a further development of the method, grayscale images are determined as control signals for adjusting the brightness distribution of the pixel light sources. These grayscale images are suitable for reliably controlling the pixel light sources with minimal data transmission and processing effort.

[0022] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0023] This shows: Fig. 1. Schematic representation of a first design example of a headlight for a vehicle according to the state of the art. Fig. 2. Schematically, a second example of the design of a headlight for a vehicle according to the state of the art. Fig. 3 schematically a first embodiment of a headlight according to the invention for a vehicle, and Fig. 4 schematically a second embodiment of a headlight according to the invention for a vehicle.

[0024] Corresponding parts are marked with the same reference symbols in all figures.

[0025] In Fig. Figure 1 is a first example of a headlight 1 for a vehicle according to the state of the art.

[0026] The headlight 1 comprises a pixel light source 2.1, also referred to as a light-emitting diode array, light-emitting diode array or LED array, which includes several light-emitting diodes, micromirrors or other individual light sources, in particular arranged in several columns and rows and individually controllable.

[0027] The pixel light source 2.1 is designed to generate various light distributions, in particular low beam, partial high beam, and high beam distributions. Specifically, the individual light sources can be controlled independently such that one or more light-dark boundaries of the generated light distribution can be variably created and positioned. For generating the light distribution and controlling the pixel light source 2.1, it is coupled to a control unit 3.1. A data transmission interface 4.1 with a communication channel is provided for this coupling and for supplying electrical power to the pixel light source 2.1.

[0028] To generate further lighting functions, in particular so-called basic lighting functions such as parking lights and daytime running lights, additional individual LEDs 5.1 to 5.4 are provided. For control and electrical supply of these individual LEDs 5.1 to 5.4, they are coupled to a common control unit 6 via a further data transmission interface 7.

[0029] Fig. Figure 2 shows a second embodiment of a headlight 1 for a vehicle according to the prior art. In order to produce higher illuminance and resolution of the generated light distribution or the generated light pattern, the second embodiment of the headlight 1 according to the prior art comprises, in addition to the one shown in Fig. In the first embodiment shown in Figure 1, a second pixel light source 2.2 is provided, which is controlled by a separate control unit 3.2. A data transmission interface 4.2 with a communication channel is provided for coupling with this control unit 3.2 and for supplying electrical power to the pixel light source 2.2. Pixel light sources 2.1 and 2.2 with different technologies and resolutions can be used.

[0030] In Fig. Figure 3 shows a possible first embodiment of a headlight 1 according to the invention for a vehicle.

[0031] Unlike the one in Fig. In the second embodiment of the headlight 1 shown in Figure 2 according to the prior art, the headlight 1 according to the possible first embodiment according to the invention comprises a common control unit 8, which includes a data transmission interface 9 with two data transmission channels 9.1, 9.2. Each data transmission channel 9.1, 9.2 is assigned exactly one pixel light source 2.1, 2.2.

[0032] The control unit 8 generates corresponding control signals for controlling the pixel light sources 2.1 and 2.2, which are bundled and transmitted via a communication channel 9.3 to a selection circuit 9.4 located and switched between the pixel light sources 2.1 and 2.2 and the communication channel 9.3. The selection circuit 9.4, also known as a demultiplexer, decodes the control signals so that they are switched through to the respective pixel light sources 2.1 and 2.2.

[0033] Fig.Figure 4 shows a second embodiment of a headlight 1 according to the invention for a vehicle.

[0034] This embodiment also includes a common control unit 8 for controlling the pixel light sources 2.1, 2.2. The data transmission interface 9, designed for example as a video interface, includes several data transmission channels 9.1, 9.2 designed as color channels, in the illustrated embodiment a red channel (= data transmission channel 9.1) and a green channel (= data transmission channel 9.2).

[0035] The control unit 8 contains two graphics algorithms, P1 and P2, which generate a grayscale image for each pixel light source 2.1 and 2.2 to adjust the respective brightness distribution of these pixel light sources. A serializer 9.5 serializes the control signals describing the grayscale images at the output of the graphics algorithms P1 and P2, converting them to an image size and frame rate corresponding to a maximum of the two graphics algorithms P1 and P2.

[0036] This data is then transmitted via communication channel 9.3, in which the two data transmission channels 9.1 and 9.2 are bundled, to a deserializer 9.6. In the illustrated embodiment, communication channel 9.3 is a low-voltage differential signaling channel, or LVDS channel for short; however, in other embodiments not shown, it may also be implemented using a different technology.

[0037] The deserializer 9.6, located between the pixel light sources 2.1, 2.2 and the communication channel 9.3, decodes the control signals and assigns them to the respective pixel light source 2.1, 2.2 and switches them through. In one possible embodiment, the control signals describing the grayscale images can be scaled to corresponding image sizes and frame rates according to the sizes of the pixel light sources 2.1, 2.2.

[0038] In other embodiments not shown, the data transmission interface 9 comprises three color channels and forms a so-called RGB interface (R = Red, G = Green, B = Blue). Here, the three color channels can be used to transmit control signals to three pixel light sources, or several color channels can be combined into a single communication channel, thus achieving higher dynamic range and resolution of the grayscale images and, consequently, the generated light distributions. For example, the three color channels are operated with an 8-bit brightness resolution, i.e., with a total of 24 bits. If the three color channels are combined into two color channels, the two color channels can each be operated with a 12-bit brightness resolution. Reference symbol list 1 headlight 2.1 Light-emitting diode array or pixel light source 2.2 Light-emitting diode array or pixel light source 3.1 Control unit 3.2 Control unit 4.1 Data transmission interface 4.2 Data transmission interface 5.1 to 5.4 Light-emitting diodes for signal light functions 6 Control unit 7 Data transmission interface 8 Control unit 9 Data transmission interface 9.1 Data transmission channel 9.2 Data transmission channel 9.3 Communication channel 9.4 Selection circuit 9.5 Serializer 9.6 Deserializer P1 Graphics Algorithm P2 graphics algorithm

Claims

[1] Headlights (1) for a vehicle with - a plurality of multiple pixel light sources (2.1, 2.2) and - at least one electronic control unit (8) for controlling the pixel light sources (2.1, 2.2), wherein - the control unit (8) includes or is coupled to at least one data transmission interface (9) with a plurality of data transmission channels (9.1, 9.2) and - each data transmission channel (9.1, 9.2) is assigned a maximum of one pixel light source (2.1, 2.2), characterized by , that - the majority of the data transmission channels (9.1, 9.2) are bundled into at least one communication channel (9.3) and - a selection circuit (9.4) is arranged between the communication channel (9.3) and the pixel light sources (2.1, 2.2) for switching control signals transmitted via the communication channel (9.3) to the pixel light sources (2.1, 2.2) and - the data transmission interface (9) is a video interface. [2] Headlight (1) according to claim 1, characterized by , that a pixel light source (2.1, 2.2) is assigned to several bundled data transmission channels (9.1, 9.2). [3] Headlight (1) according to claim 1 or 2, characterized by , that the communication channel (9.3) is a low-voltage differential signaling channel. [4] Headlight (1) according to any one of the preceding claims, characterized by , that the data transmission interface (9) comprises several data transmission channels (9.1, 9.2) configured as color channels. [5] Headlight (1) according to claim 4, characterized by , that each color channel is designed to transmit at least one grayscale image as a control signal to generate a light distribution to the respective pixel light source (2.1, 2.2). [6] Method for operating a headlight (1) for a vehicle, wherein - a plurality of pixel light sources (2.1, 2.2) are controlled by at least one electronic control unit (8), - control signals are transmitted from the control unit (8) to the pixel light sources (2.1, 2.2) via a data transmission interface (9) and - the control signals at each pixel light source (2.1, 2.2) are transmitted separately via at least one data transmission channel (9.1, 9.2) of the data transmission interface (9) assigned to the respective pixel light source (2.1, 2.2), characterized by , that control signals transmitted via the communication channel (9.3) are switched to the pixel light sources (2.1, 2.2) by means of a selection circuit (9.4) arranged between a communication channel (9.3) bundled from the majority of the data transmission channels (9.1, 9.2) and the pixel light sources (2.1, 2.2), wherein the data transmission interface (9) is a video interface. [7] Method according to claim 6, characterized by , that grayscale images are generated as control signals to adjust a brightness distribution for the pixel light sources (2.1, 2.2).

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