Light emitting device, control unit, and adaptive driving beam headlights

Abstract

A light emitting device (100) comprises a pixel unit (102) having an array (105) of light emitting pixels (110), wherein each light emitting pixel (110) is separately controllable to emit light. The pixel unit (102) is configured to receive pixel control data that indicate pixel values for a part of the light emitting pixels (110) and to control light emission of said part of the light emitting pixels (110) according to the received pixel control data, while the remainder of the light emitting pixels (110) is controlled to emit light according to previously received pixel control data.

Description

[0001] LIGHT EMITTING DEVICE, CONTROL UNIT, AND ADAPTIVE DRIVING BEAM HEADLIGHTS

[0002] The present disclosure relates to a light emitting device, a light source, and adaptive driving beam headlights used in a car as well as to a control unit and a control method for said devices.

[0003] Adaptive driving beam, ADB, headlights that are used for example as car headlights allow to adaptively adjust the light emission within the field of view of the headlights such as to avoid e.g. blinding of oncoming traffic, while still illuminating the road.

[0004] Driving a high resolution ADB headlights system requires in principle a high frequency video interface to ensure the necessary bandwidth. However, only a low bandwidth interface may be provided in an already existing car platform. Thus, for equipping such a car, reduction of the bandwidth, i.e. the data processing and transmission rates, towards the light emitting device used in the ADB headlights is necessary. Moreover, reduced bandwidth would also allow to use less cost intensive components. Thus, reducing the bandwidth also allows manufacturing of less expensive light emitting devices that can be used e.g. in ADB headlights.

[0005] It is an objective of the present invention to provide an improved light emitting device, an improved light source, and an improved ADB headlight as well as control units and methods for these devices.

[0006] According to embodiments, the above object is achieved by the claimed matter according to the independent claims. Further developments are defined in the dependent claims.

[0007] Embodiments relate to a light emitting device that comprises a pixel unit having an array of light emitting pixels, wherein each light emitting pixel is separately controllable to emit light. The pixel unit is configured to receive pixel control data that indicate pixel values for a part of the light emitting pixels and to control light emission of said part of the light emitting pixels according to the received pixel control data, while the remainder of the light emitting pixels is controlled to emit light according to previously received pixel control data.

[0008] The pixel control data may indicate pixel values for a group of adjacent light emitting pixels.

[0009] The array of light emitting pixels may be formed by rows and columns of light emitting pixels and the pixel control data may indicate pixel values for one or a plurality of rows and / or columns.

[0010] The pixel control data may specify a type of a pixel region to which the pixel values indicated by the pixel control data refer, a location of the specified pixel region, and a size of the specified pixel region.

[0011] The pixel unit may be configured to receive the pixel control data with a rate that is higher than or equal to 20 / s, 30 / s, 60 / s, 90 / s, or 120 / s.

[0012] The pixel unit may be configured to receive the pixel control data with a bandwidth of less than or equal to 1 Mbit / s, 2 Mbit / s, 5 Mbit / s, or 10 Mbit / s.

[0013] The light emitting device may further comprise a first memory and a second memory for buffering pixel values indicated by the pixel control data. Here, the first memory may be smaller than the second memory, the second memory may be configured to buffer pixel values for all light emitting pixels, and the first memory may be configured to buffer pixel values for the part of the light emitting pixels to which the pixel control data refer, but not to buffer pixel values for all light emitting pixels.

[0014] Alternatively, the first memory and the second memory are each configured to buffer pixel values for all light emitting pixels. Then, in a first time step the pixel unit may be configured to read out pixel values from the first memory to control light emission of all light emitting pixels. During readout of the first memory, the first memory may be configured to copy pixel values from the first memory to the second memory and the pixel unit may be configured to write pixel values indicated by current pixel control data over the copied pixel values in the second memory. In a consecutive, second time step the above operations may be repeated with the roles of the first memory and the second memory being swapped.

[0015] Further, a control unit is provided for controlling a light emitting device that comprises a pixel unit having an array of light emitting pixels, wherein each light emitting pixel is separately controllable to emit light. The control unit is configured to generate pixel control data that indicate pixel values for a part of the light emitting pixels and to transmit the pixel control data to the light emitting device.

[0016] The control unit may be configured to transmit the pixel control data with a rate that is higher than or equal to 20 / s, 30 / s, 60 / s, 90 / s, or 120 / s.

[0017] The control unit may be configured to transmit the pixel control data with a bandwidth of less than or equal to 1 Mbit / s, 2 Mbit / s, 5 Mbit / s, or 10 Mbit / s.

[0018] A light emitting system may comprise the light emitting device and the control unit as described above.

[0019] The light emitting system may further comprise a receiving unit that is configured to receive image data and / or video data of a field of view that is illuminated by the light emitting pixels. The control unit may be configured to generate the pixel control data based on received image data or video data.

[0020] A light source for adaptively illuminating a field of view may comprise a light emitting device as described above and optics that focusses the light emitted by the light emitting pixels onto the field of view.

[0021] Adaptive driving beam headlights may comprise a light source as described above.

[0022] A car may comprise the light emitting system as described above, where the light emitting device is preferably comprised in adaptive driving beam headlights as described above. The control unit may be configured to generate pixel control data such as to avoid blinding of oncoming traffic and / or to project messages to a driver of the car. A method is provided for operating a light emitting device that comprises a pixel unit having an array of light emitting pixels, wherein each light emitting pixel is separately controllable to emit light, the method comprising: receiving, by the pixel unit, pixel control data that indicate pixel values for a part of the light emitting pixels; and controlling, by the pixel unit, light emission of said part of the light emitting pixels according to the received pixel control data, while the remainder of the light emitting pixels is controlled to emit light according to previously received pixel control data.

[0023] BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the present invention and together with the description serve to explain the principles. Other embodiments of the invention and many of the intended advantages will be readily appreciated, as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numbers designate corresponding similar parts.

[0025] Fig. 1 is a schematic illustration of a light emitting device.

[0026] Fig. 2 is a schematic illustration of pixel control data.

[0027] Fig. 3 is a schematic illustration of data transfer in the light emitting device.

[0028] Fig. 4 is another schematic illustration of data transfer in the light emitting device.

[0029] Figs. 5 to 11 show examples for an adaption of light emission by the light emitting device.

[0030] Fig. 12 shows a schematic flow diagram of a method for operating a light emitting device. Fig. 13 is a schematic illustration of a light source comprising a light emitting device.

[0031] Fig. 14 is a schematic illustration of a car using adaptive driving beam headlights comprising a light emitting device.

[0032] DETAILED DESCRIPTION

[0033] In the following detailed description reference is made to the accompanying drawings, which form a part hereof and in which are illustrated by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology such as "top", "bottom", "front", "back", "over", "on", "above", "leading", "trailing" etc. is used with reference to the orientation of the Figures being described. Since components of embodiments of the invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope defined by the claims.

[0034] The description of the embodiments is not limiting. In particular, elements of the embodiments described hereinafter may be combined with elements of different embodiments.

[0035] Fig. 1 is a schematic illustration of a light emitting device 100 that is configured to emit light into a certain solid angle, also called field of view of the light emitting device 100.

[0036] The light emitting device 100 comprises at least a pixel unit 102 as the light emitting part of the light emitting device 100. The pixel unit 102 comprises an array 105 of light emitting pixels 110, wherein each light emitting pixel 110 is separately controllable to emit light. The light emitting pixels 110 are two-dimensionally arranged in the array 105. As shown in Fig. 1 the pixels 110 may be regularly arranged and form e.g. rows and columns of a two-dimensional matrix. However, the pixels 110 may also be arranged non-regularly. For example, the pixels 110 may have different densities in different areas of the array. The pixels 110 may also be arranged along a straight or curved line or such as to form a certain pattern. Thus, the arrangement of the pixels 110 is arbitrary.

[0037] Each of the pixels 110 is configured to emit light independent of light emission by the other pixels 110. Thus, each pixel 110 is separately controllable to emit light of a certain brightness. Preferably, the pixels 110 are LEDs or laser diodes. However, the pixels 110 may in principle also be constituted by any light emitter, such as a plurality of incandescent lamps or halogen lamps. The light emitted by the pixels 110 is preferably visible light and most preferably white light. However, the pixels 110 may in principle also emit infrared or ultraviolet light. In principle, the structure of the light emitting pixels 110 and of the pixel unit 102 is known and a more detailed description thereof can be omitted here.

[0038] By being separately controllable, the light emitting pixels 110 can illuminate the field of view of the light emitting device 100 in an adaptive manner, i.e. within the field of view regions of high illumination and regions of low or no illumination can be defined and dynamically changed.

[0039] To this end, the pixel unit 102 is configured to receive pixel control data D that indicate pixel values (i.e. pixel brightness values) for a part of the light emitting pixels 110. The pixel unit 102 controls light emission of said part of the light emitting pixels 110 according to the received pixel control data D, while the remainder of the light emitting pixels 110 is controlled to emit light according to previously received pixel control data D.

[0040] That is, pixel control data D are not provided every time to all pixels 110 of the pixel unit 102. Instead, only a part of the pixels 110 is updated based on newly received pixel control data D, while the rest of the pixels 110 is maintained in their previous light emission state. Thus, instead of transmitting a full frame of pixel data, i.e. pixel control data D for each pixel 110, only a partial frame is transmitted.

[0041] This allows dynamic adaption of the spatial distribution of light emission by the light emitting device 100, while reducing the amount of data transmission considerably. In turn, adaption of light emission can be performed either more often, i.e. with lower latency, or control of light emission may be performed with less bandwidth. This allows using the light emitting device 100 in systems that do not possess data transmission bandwidths that would be necessary to transmit full frames of pixel data. In addition, in setting up light emission systems comprising the light emitting device 100 less expensive data transmission paths with a lower bandwidth can be used.

[0042] Here, as indicated in Fig. 1 the pixel control data D may indicate pixel values for a group 115 of adjacent light emitting pixels 110. These groups 115 may be for example one or a plurality of rows and / or columns. However, the groups 115 may also be freely definable areas of pixels 110 such as rectangular areas in a two- dimensional pixel array 105 or even single pixels 110. The pixel control data D may in principle be directed to any type of such groups and may also refer to different types at different times. The pixel control data may also refer to several disjunct groups 115 of pixels 110. Thus, a flexible adaption of the spatial distribution of light emission of the light emitting device 100 is possible.

[0043] Here, referring to columns / rows of the array 105 makes the assignment of the location of the pixels 110 to be updated easy. It suffices to indicate a starting column / row and the number of columns / rows to be updated. On the other hand, freely definable pixel areas provide the largest flexibility, while needing more information regarding position and size of the area. For example, indicating a rectangular region needs the position of a pixel 110 at one corner of the rectangle as well as the width and the height of the rectangle.

[0044] Possible formats for the pixel control data D are illustrated in Fig. 2. The pixel control data D may specify a type T of a pixel region (such as column, row, rectangular area, single pixel) to which the pixel values V indicated by the pixel control data D refer, a location L of the specified pixel region (such as an initial column or row, a corner of a rectangular area, or the location of the single pixel), and a size S of the specified pixel region (such as the number of columns or rows, or the width and height of a rectangular area). In addition, a header H and cyclic redundancy check, CRC, bits can be included in the pixel control data D. As exemplary illustrated in Fig. 2 the arrangement of the different information present in the pixel control data D is in principle arbitrary. For example, the pixel values V indicated by the pixel control data D may be arranged after, before or between the specification of the type T, location L, and size S of the specified pixel region. Further, also other manners of specifying the pixel region are conceivable and the pixel control data D are not limited to the examples discussed with respect to Fig. 2. The various data blocks of control data D are usually transferred from left to right in Fig. 2, i.e. the header H is transferred first and the CRC bits last. However, the transfer order is in principle arbitrary and depends on the used transfer protocol.

[0045] The pixel control data D are provided from a control unit 120 to the light emitting device 100.

[0046] As illustrated in Fig. 1 the control unit 120 may be located externally to the light emitting device 100 and form a light emitting system 1000 with the light emitting device 100. The control unit 120 may for example be part of a control system controlling more than only the light emitting device 100, such as e.g. the ECU of a car. The control unit 120 may in principle also be located remotely at a server or a server farm. However, the control unit 120 may also be included in the same housing as the pixel unit 102. It may, for example, be located on the same circuit board as the pixel unit 102 or on a circuit board next to the circuit board of the pixel unit 102. In this case, the locally provided control unit 120 may carry out its actions under control of an externally provided control system. Further, a locally provided control unit 120 may execute any computing / control tasks of the pixel unit 102 or may be a control unit of the pixel unit 102.

[0047] The control unit 120 may be a component of a general purpose processor or may be constituted by a general purpose processor. It may be constituted by a CPU, a GPU or any circuitry that is capable to carry out the functions described above. These functions may be hardware implemented, software based or executed by a mixture of hardware and software. In particular, the control unit 120 may be a FPGA or an ASIC. The control unit 120 generates the pixel control data D that indicate the pixel values for the part of the light emitting pixels 110 and transmits them to the light emitting device 100. The control unit 120 may generate the pixel control data D e.g. based on data on the environment of the light emitting device 100.

[0048] For example, if the light emitting device 100 is used in headlights or a flashlight, brightness could be reduced in the direction to the face of a human in order to avoid blinding based on face detection technology. If the light emitting device is used as a photoflash or for illumination of a scene, brightness could be reduced in the direction of highly reflective surfaces to reduce specular reflexes. Brightness could be increased in regions of particular interest, e.g. in the direction of the roadside in the headlights example, or in the direction of an interesting object in the example of illuminating a scene.

[0049] To this end, the light emitting system 1000 may comprise a receiving unit 140 that is configured to receive image data and / or video data of a field of view that is illuminated by the light emitting pixels 110, wherein the control unit 120 is configured to generate the pixel control data D based on received image data or video data.

[0050] The control unit 120 may also receive sensor signals such as an accelerometer signal to determine direction changes of the field of view of the light emitting device 100. For example, if used in a car, the control unit 120 may receive signals indicating sudden changes of the orientation of the car in space, such as occurring e.g. when driving over a bump or a hole, and may generate the pixel control data D based on this information.

[0051] In general, the control unit 120 generates the pixel control data D based on external information such as to improve the intended function of the light emitting device 100 by dynamically adapting light emission of the light emitting device 100.

[0052] The pixel control data D may be generated by the control device 120 and / or received by the light emitting device 100 with a rate that is higher than or equal to 20 / s, 30 / s, 60 / s, 90 / s, or 120 / s in order to ensure a frequent and dynamic adaption of light emission with low latency. Also, the pixel control data D may be exchanged between the control unit 120 and the light emitting device 100 / the pixel unit 102 with a bandwidth of less than or equal to 1 Mbit / s, 2 Mbit / s, 5 Mbit / s, or 10 Mbit / s. Since only pixel control data for a part of the pixels 110 are transmitted, it is possible to use low bandwidth interfaces between the control unit 120 and the light emitting device 100. This allows using the light emitting device 100 in light emitting systems 1000 that only provide such low bandwidth interfaces, as e.g. CAN busses, or using less expensive components for the interfaces of such light emitting systems 1000.

[0053] As illustrated in Fig. 1 the light emitting device 100 may comprise at least two different memories, termed first memory 130 and second memory 135 in the following, for buffering pixel values indicated by the pixel control data D. The first memory 130 and the second memory 135 may be located in the pixel unit 102, e.g. on the same circuit board as the array 105. They may, however, also be located on a different circuit board or outside the pixel unit 102. In principle, any type of memory can be used for the first memory 130 and the second memory 135, as long as it allows buffering of the pixel values used to control light emission of the pixels 110. It is also possible to use a single memory to implement the functions of the first memory 130 and the second memory 135. However, this bears the risk of glitches when switching memory functions. Hence, the usage of two different memories is preferred.

[0054] Here, as schematically illustrated in Fig. 3, the first memory 130 may be smaller than the second memory 135. While the second memory 135 is configured to buffer pixel values for all light emitting pixels 110, the first memory 130 is configured to buffer pixel values for the part of the light emitting pixels 110 to which the pixel control data D refer but is not configured to buffer pixel values for all light emitting pixels 110.

[0055] In particular, as schematically indicated in Fig. 3, the control unit 120 provides the pixel control data D to the first memory 130, which stores the pixel values V contained in the pixel control data D. To this end, the first memory 130 only needs to be of a size that allows storing these pixel values. For example, if only a single pixel row is to be updated at a time, it is sufficient when the first memory 130 has a size that allows storing the pixel values for this single row. Assuming an array 105 of 80 rows and 320 columns and a size of pixel values of 8 bits, the first memory 130 only needs to have a size of 320 x 8 bits.

[0056] From the first memory 130 the buffered pixel values V will be provided to the second memory 135, which constitutes a full frame buffer, i.e. a buffer that can store pixel values for all pixels 110, and which is read out by the pixel unit 102 / the array 105 to control light emission of the pixels 110 in the array 105. In the second memory 135 only the pixel values provided from the first memory 130 will be overwritten, while the remaining pixel values are maintained. In this manner only the light emission of the pixels 110 for which pixel control data D were received are adapted, while light emission of the other pixels 110 is kept constant.

[0057] Compared to a system in which always full frame information is provided, i.e. pixel values for all pixels 110, this allows saving memory space, and hence saving physical space and cost. In particular, since it is not possible to read from and write to a memory at the same time, for full frame solutions two memories need to be provided that have sufficient storage space for pixel values of all pixels: one for storing newly received pixel values and one for providing pixel values stored in the previous time step to the pixel array 105.

[0058] Thus, using the present light emitting device 100 it is not only possible to reduce the bandwidth requirements, but also to save memory space. In the above example of an array of 80 x 320 pixels 110, a full frame memory needs at least 80 x 320 x 8 bits memory space. By replacing one of these full frame memories by a smaller memory that only has memory space for the partial frame indicated by the pixel control data D a considerable amount of memory space can be saved. In the above example of one row update at a time, the reduction will be 79 x 8 bits.

[0059] On the other hand, pixel control data D for partial frames can also be used in systems comprising two full frame memories, i.e. in light emitting devices 100 in which both the first memory 130 and the second memory 135 are configured to store pixel values for all pixels 110. This is schematically illustrated in Fig. 4. Here, in a first time step (illustrated in the upper part of Fig. 4) the pixel unit 102 / the pixel array 105 is configured to read out pixel values from the first memory 130 to control light emission of all light emitting pixels 110. During readout of the first memory 130, the first memory 130 is configured to copy pixel values from the first memory 130 to the second memory 135. This is possible since the copying process constitutes an additional read operation on the first memory 130. At the same time the pixel unit 102 is configured to write pixel values indicated by current pixel control data D over the copied pixel values in the second memory 135. Again, this is possible since the copying process constitutes an additional write operation on the second memory 135. In this manner, the second memory 135 contains the updated light emission frame, in which the part of the pixels 110 that were referred to be the current pixel control data D are updated.

[0060] This updated light emission frame is readout in a consecutive, second time step where the above operations are repeated with the roles of the first memory 130 and the second memory 135 being swapped. This means during readout of the second memory 135, the pixel values contained in this memory are copied to the first memory 130 and partially overwritten with the pixel values indicated in the newly received pixel control data D. By reiterating the process in this manner it is possible to implement the usage of partial pixel control data in light emitting devices containing two full frame memory buffers.

[0061] Figs. 5 to 11 provide different use examples of the above techniques that should allow a better understanding of these techniques. Each of Figs. 5 to 11 show examples of an illumination provided by a light emitting device having 80 rows and 320 columns of pixels which is used in headlights of cars. The upper part of each of Figs. 5 to 11 shows an illumination state before updating, while the lower part shows the state after updating together with the updated region.

[0062] Fig. 5 shows an example of a reaction to the recognition of oncoming traffic. To avoid glaring of the oncoming traffic 10, pixel columns are updated, in the upper part of which light emission was turned off, while in the lower part no adaption of light emission was performed. In Fig. 6, the oncoming traffic moves to the left. Thus, the switched off pixels 110 also need to be moved to the left. To this end, two disjunct sets of pixel columns where updated. First, by updating the five columns to the left of the switched off pixels 110, it is accounted for the left-moving oncoming traffic. Second, by updating the five columns containing the right half of the switched off pixels 110, sufficient road illumination in the region in which the oncoming traffic is no longer present is ensured.

[0063] In the example of Fig. 7 a hazard appears in the upper right of the field of view of the light emitting device 100. To illuminate this hazard light emission in a corresponding pixel area is increased by updating the respective pixel columns.

[0064] In Fig. 8 an informative marker indicating an icy road is projected onto the road by updating the corresponding columns of the array 105.

[0065] Fig. 9 shows the same informative marker, however, generated by updating a rectangular pixel area containing the marker and not the entire pixel columns. Of course, also in the examples of Figs. 5 to 7 rectangular pixel regions could have been used instead of pixel columns.

[0066] Fig. 10 refers to a situation where the illumination range of the light emitting device 100 changes due to a bump on the road. In order to avoid glaring of existing oncoming traffic, it is necessary to switch off additional pixels 110 below the already switched off pixels 110. This is done by updating several rows of pixels 110. Since driving over a bump happens quickly, it is important to have high update rates, i.e. low data rates, which is guaranteed by only updating the necessary parts of the array 105.

[0067] This effect can even be increased by updating only a rectangular area containing the very pixels 110 that are to be switched off, as illustrated in Fig. 11 .

[0068] By using a light emitting device 100 as described above it is therefore possible to dynamically adapt the illumination provided by the light emitting device 100 without providing high bandwidth interfaces. The operation of the light emitting device 100 can summarized as illustrated in Fig. 12. At S110 the pixel unit 102 receives pixel control data D that indicate pixel values for a part of the light emitting pixels. At S120 the pixel unit 102 controls light emission of said part of the light emitting pixels 110 according to the received pixel control data D, while at S130 the remainder of the light emitting pixels 110 is controlled to emit light according to previously received pixel control data D.

[0069] Fig. 13 shows an implementation of a light emitting device 100 within a light source 200 that is configured to adaptively illuminate a field of view by using the abovedescribed functions of the light emitting device 100. In particular, the light source projects the light emitted from the light emitting pixels 110 through optics 210 to focus it onto the field of view. When implementing the light emitting device 100 in such a light source 200, the above references to the field of view of the light emitting device 100 are to be understood as references to the field of view of the light source 200.

[0070] This means, the control unit 120 operates on images / videos of the field of view of the light source 200 as received by the receiving unit 140. Here, the control unit 120 may by part of the light source 200 or may be an external device.

[0071] The light source 200 may further comprise or may be connected to an imaging device which constitutes the receiving unit 140. The implementation of this imaging device is in principle arbitrary. Any imaging device can be used that is capable to provide image / video data to the control unit 120 with a sufficiently high frame rate (e.g. 60 frames per second).

[0072] The imaging device may also be an external unit that is not part of the light source 200 but provides data to the light source 200 / the control unit 120. For example, the imaging device may be part of a car electronic system. In particular, the imaging device may be placed on or within a driving mirror and provides imaging data to a central control unit of the car electronic system.

[0073] The control unit 120 is configured to determine, based on the images and / or videos captured by the imaging device, regions in the field of view that shall not be illuminated and / or regions that are to be illuminated at reduced intensity, and is configured to generate the selection control signals based thereon.

[0074] Thus, as described above, due to the functions of the light emitting device 100 the light source 200 can adaptively illuminate a scene, in particular based on the images / video from the imaging device.

[0075] The light source may in particular be or be included into adaptive driving beam, ADB, headlights 300. In such headlights the control unit 120, and - if present - the receiving unit 140 may be implemented by a service interface that can also be used for diagnosis of the headlights 300. In particular, it is not necessary that the ADB headlights use or comprise a video interface that is configured to provide and / or process video data with a high bandwidth of 20 Mbit / s needed for high resolutions of e.g. 320x80 pixels. In fact, by using the memory 120 and the selection control signals to control the light emitting pixels 110, the necessary bandwidth can be reduced such that communication via the service interface (bandwidth in the range of 1 Mbit / s to 2 Mbit / s but fundamentally below 5 Mbit / s available for lower bandwidth CAN-FD transceivers) is sufficient.

[0076] This simplifies the ADB headlights and make it compatible with cars that do not comprise a high bandwidth video interface.

[0077] As shown in Fig. 14 a car 400 may comprise the light emitting system 1000 and in particular the ADB headlights 300 as described above. Then, the control unit 120 provides pixel control data to avoid blinding of oncoming traffic and / or to project messages to a driver of the car 400 into the field of view of the light source. An accordingly equipped car 400 enhances therefore road safety.

[0078] While embodiments of the invention have been described above, it is obvious that further embodiments may be implemented. For example, further embodiments may comprise any subcombination of features recited in the claims or any subcombination of elements described in the examples given above. Accordingly, this spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. In particular, the virtual pixels may only be realized on the signal processing and silicon side, where on the other side the light emitting pixels may be executed in reality in the size of those virtual pixels on the silicon side. This creates also benefits of higher efficiency with coarser light emitting pixels but does not require new silicon designs at the same time.

[0079] LIST OF REFERENCES

[0080] 1000 Light emitting system

[0081] 100 Light emitting device

[0082] 102 Pixel unit

[0083] 105 Array of light emitting pixels

[0084] 110 Light emitting pixels

[0085] 115 Group of pixels

[0086] 120 Control unit

[0087] 130 First memory

[0088] 135 Second memory

[0089] 140 Receiving unit

[0090] 200 Light source

[0091] 210 Optics

[0092] 300 Adaptive driving beam headlights

[0093] 400 Car

[0094] D Pixel control data

[0095] T Type of a pixel region

[0096] L Location of a pixel region

[0097] S Size of a pixel region

[0098] V Pixel values

[0099] C CRC bits

Claims

CLAIMS1 . A light emitting device (100) comprising: a pixel unit (102) having an array (105) of light emitting pixels (110), wherein each light emitting pixel (110) is separately controllable to emit light; wherein the pixel unit (102) is configured to receive pixel control data (D) that indicate pixel values for a part of the light emitting pixels (110) and to control light emission of said part of the light emitting pixels (110) according to the received pixel control data (D), while the remainder of the light emitting pixels (110) is controlled to emit light according to previously received pixel control data (D).

2. The light emitting device (100) according to claim 1 , wherein the pixel control data (D) indicate pixel values for a group (115) of adjacent light emitting pixels (110).

3. The light emitting device (100) according to anyone of the preceding claims, wherein the array (105) of light emitting pixels (110) is formed by rows and columns of light emitting pixels (110); and the pixel control data (D) indicate pixel values for one or a plurality of rows and / or columns.

4. The light emitting device (100) according to anyone of the preceding claims, wherein the pixel control data (D) specify a type (T) of a pixel region to which the pixel values (V) indicated by the pixel control data refer, a location (L) of the specified pixel region, and a size (S) of the specified pixel region.

5. The light emitting device (100) according to anyone of the preceding claims, wherein the pixel unit (102) is configured to receive the pixel control data (D) with a rate that is higher than or equal to 20 / s, 30 / s, 60 / s, 90 / s, or 120 / s.

6. The light emitting device (100) according to anyone of the preceding claims, wherein the pixel unit (102) is configured to receive the pixel control data (D) with a bandwidth of less than or equal to 1 Mbit / s, 2 Mbit / s, 5 Mbit / s, or 10 Mbit / s.

7. The light emitting device (100) according to anyone of the preceding claims, further comprising a first memory (130) and a second memory (135) for buffering pixel values indicated by the pixel control data (D); wherein the first memory (130) is smaller than the second memory (135); the second memory (135) is configured to buffer pixel values for all light emitting pixels (110); and the first memory (130) is configured to buffer pixel values for the part of the light emitting pixels (110) to which the pixel control data (D) refer but is not configured to buffer pixel values for all light emitting pixels (110).

8. The light emitting device (100) according to anyone of claims 1 to 6, further comprising a first memory (130) and a second memory (135) that are each configured to buffer pixel values for all light emitting pixels (110); wherein in a first time step the pixel unit (102) is configured to read out pixel values from the first memory (130) to control light emission of all light emitting pixels (110); during readout of the first memory (130), the first memory (130) is configured to copy pixel values from the first memory (130) to the second memory (135) and the pixel unit (102) is configured to write pixel values indicated by current pixel control data (D) over the copied pixel values in the second memory (135); and in a consecutive, second time step the above operations are repeated with the roles of the first memory (130) and the second memory (135) being swapped.

9. A control unit (120) for controlling a light emitting device (100) that comprises a pixel unit (102) having an array (105) of light emitting pixels (110), wherein each light emitting pixel (110) is separately controllable to emit light, the control unit (120) being configured togenerate pixel control data (D) that indicate pixel values for a part of the light emitting pixels (110), and transmit the pixel control data (D) to the light emitting device (100).

10. The control unit (120) according to claim 9, wherein the control unit (120) is configured to transmit the pixel control data (D) with a rate that is higher than or equal to 20 / s, 30 / s, 60 / s, 90 / s, or 120 / s.11 . The control unit (120) according to claim 9 or 10, wherein the control unit (120) is configured to transmit the pixel control data (D) with a bandwidth of less than or equal to 1 Mbit / s, 2 Mbit / s, 5 Mbit / s, or 10 Mbit / s.

12. A light emitting system (1000) comprising the light emitting device (100) according to anyone of claims 1 to 8; and the control unit (120) according to anyone of claims 9 to 11 .

13. The light emitting system (1000) according to claim 12, further comprising a receiving unit (140) that is configured to receive image data and / or video data of a field of view that is illuminated by the light emitting pixels (110); wherein the control unit (120) is configured to generate the pixel control data (D) based on received image data or video data.

14. A light source (200) for adaptively illuminating a field of view, the light source (200) comprising: a light emitting device (100) according to anyone of claims 1 to 8; and optics (210) that focusses the light emitted by the light emitting pixels (110) onto the field of view.

15. Adaptive driving beam headlights (300) comprising a light source (200) according to claim 14.

16. A car (400) comprising the light emitting system according to claim 12 or13, where the light emitting device is preferably comprised in adaptive driving beam headlights (300) according to claim 15, whereinthe control unit (120) is configured to generate pixel control data (D) such as to avoid blinding of oncoming traffic and / or to project messages to a driver of the car (400).

17. A method for operating a light emitting device (100) that comprises a pixel unit (102) having an array (105) of light emitting pixels (110), wherein each light emitting pixel (110) is separately controllable to emit light, the method comprising: receiving, by the pixel unit (102), pixel control data (D) that indicate pixel values for a part of the light emitting pixels (110); and controlling, by the pixel unit (102), light emission of said part of the light emitting pixels (110) according to the received pixel control data (D), while the remainder of the light emitting pixels (110) is controlled to emit light according to previously received pixel control data (D).

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