Projection vehicle lamp electronic system based on CAN XL
The CAN XL-based projection vehicle lighting electronic system solves the problems of bandwidth waste and design complexity in traditional projection vehicle lighting systems, achieving efficient transmission of display data and control signals, reducing system costs, and ensuring the accuracy of data recognition and network stability.
Patent Information
- Application Number
- CN202511453854.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-13
- Publication Date
- 2026-01-09
AI Technical Summary
Traditional projection vehicle headlight electronic systems suffer from bandwidth waste, design complexity, and high cost, especially when transmitting data for micro LED displays. Existing technologies such as GMSL and FPD LINK III protocols lead to high system complexity and increased costs.
The projection-based vehicle lighting electronic system adopts CAN XL. The vehicle-side domain controller generates and encapsulates the vehicle lighting control signals and raw display data into CAN XL data frames. The system uses the service data unit type and flag bits of the CAN XL data frames for identification and parsing, realizing the multiplexing and transmission of display data and control signals, directly transmitting pixel grayscale values, simplifying system design and reducing costs.
It achieves efficient bandwidth utilization, reduces system design complexity and cost, ensures the accuracy of data identification and network stability, and avoids conflicts and interference between devices.
Smart Images
Figure CN121309249A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a projection vehicle lighting electronic system based on CAN XL, belonging to the field of vehicle lighting control technology. Background Technology
[0002] In projection headlight systems, the transmission of display data is a crucial technology. Currently, commonly used display data transmission technologies include GMSL and FPD LINK III.
[0003] In existing technologies, the transmission rates of GMSL and FPD LINK III are generally above 1Gbps. Since both the GMSL and FPD LINK III protocols have three color components (RGB), serializers and deserializers need to be added at both ends of the transmission line. The serializers and deserializers have more than 60 pins and can support resolutions of 1080P / 2K and above. Their performance is significantly higher than the resolution requirements of micro LED, resulting in problems such as bandwidth waste, complex system design, and high cost. Summary of the Invention
[0004] The technical problem to be solved by this invention is: in view of the pain points of bandwidth waste, complex design and high cost of traditional projection vehicle lighting electronic systems in the above background technology, this invention proposes a projection vehicle lighting electronic system based on CAN XL.
[0005] The technical solution adopted by this invention to solve its technical problem is: This invention provides a projection vehicle lighting electronic system based on CAN XL, which includes a vehicle-side domain controller, a vehicle lighting controller, and a micro LED light panel; The vehicle-side domain controller is used to generate headlight control signals and raw headlight display data. Based on the service data unit type and the variable rate data frame flag and extended length frame flag in the arbitration segment, the headlight control signals and raw headlight display data are encapsulated in corresponding CAN XL data frames. Then, the headlight control signals and raw headlight display data are sent to the headlight controller through the CAN XL data frames. The service data unit type corresponding to the raw headlight display data is a vendor-defined protocol type. The vehicle lighting controller is used to identify and parse the vehicle lighting control signals and original vehicle lighting display data in the CAN XL data frame according to the service data unit type, variable rate data frame flag bit and extended length frame flag bit, and send the parsed vehicle lighting control signals and original vehicle lighting display data to the micro LED light board. The micro LED light panel is used to control the lighting function based on the analyzed vehicle light control signal, and to display images based on the analyzed original vehicle light display data.
[0006] Furthermore, when the variable rate data frame flag is dominant, the data frame is a conventional CAN data frame; when the variable rate data frame flag is recessive, the data frame is a CAN FD data frame or a CAN XL data frame.
[0007] Furthermore, when the extended length frame flag is a dominant bit, the data frame is a CAN FD data frame; when the extended length frame flag is a recessive bit, the data frame is a CAN XL data frame.
[0008] Furthermore, the identification and parsing of the vehicle headlight control signals and original headlight display data in the CAN XL data frame based on the service data unit type, variable rate data frame flag, and extended length frame flag includes: Step S1: Determine whether the variable rate data frame flag bit in the arbitration segment of the CAN XL data frame is a dominant bit. If yes, the data frame is a traditional CAN data frame. If no, proceed to step S2. Step S2: Determine whether the extended length frame flag bit in the arbitration segment of the CAN XL data frame is a dominant bit. If yes, the data in the CAN XL data frame is in CAN FD format, and jump to step S3. If no, jump to step S4. Step S3: Parse the headlight control signal according to the CAN FD data frame format; Step S4: Determine whether the service data unit type in the control segment of the CAN XL data frame is a device vendor-defined protocol type. If yes, the data segment of the CAN XL data frame contains the original display data of the vehicle lights. If not, parse it according to the corresponding service data unit type.
[0009] Furthermore, the step of sending the parsed headlight control signal and the original headlight display data to the micro LED light board includes: The parsed headlight control signals are sent to the micro LED light board via the control interface, and the parsed original headlight display data is sent to the micro LED light board via the display interface.
[0010] Furthermore, the display interface is an SPI interface, which is used for transmitting the original display data of the vehicle lights between the vehicle light controller and the micro LED light board.
[0011] Furthermore, the control interface is a UART interface or an IIC interface, both of which are used for transmitting vehicle lighting control signals between the vehicle lighting controller and the micro LED light board.
[0012] Furthermore, the original display data of the vehicle lights is the original grayscale value data of the vehicle light pixels.
[0013] Furthermore, the vehicle lighting control signal includes a status control signal and a fault diagnosis signal.
[0014] Furthermore, the service data unit type corresponding to the vehicle light control signal is the CAN standard control protocol.
[0015] The beneficial effects of this invention are: 1. Avoids bandwidth waste in display data transmission: The transmission bandwidth of CAN XL data frames is slightly higher than that of micro LEDs with tens of thousands of pixels. This not only accurately matches the transmission bandwidth requirements of micro LEDs with tens of thousands of pixels, but also avoids bandwidth waste.
[0016] 2. Reduced system design complexity and system cost: Display data and control signals are multiplexed and transmitted on the same CAN XL communication link. When using CAN XL to transmit display data, only the CAN PHY chip is needed, which reduces system design complexity and system cost.
[0017] 3. Reduced load and design requirements for the vehicle lighting controller: The display data sent by the vehicle body domain controller is the raw pixel grayscale data, which does not need to go through data conversion such as compression and decompression, thus reducing processing latency and burden, and reducing the load and design requirements of the vehicle lighting controller.
[0018] 4. Ensures the accuracy of data identification: The control segment of the CAN XL data frame defines the service data unit type, and sets the service data unit type of the displayed data to the device manufacturer's custom protocol type. While ensuring the display data transmission effect, it also ensures the accuracy of data identification and avoids conflicts and interference between network devices. Attached Figure Description
[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0020] Figure 1 This is a schematic block diagram of the projection vehicle lighting electronic system based on CAN XL of the present invention; Figure 2 This is a schematic diagram of the CAN XL data frame format of the present invention; Figure 3 This is a schematic diagram of the arbitration segment in the CAN XL data frame of the present invention; Figure 4 This is a flowchart illustrating the process of identifying and parsing vehicle headlight control signals and raw headlight display data in a CAN XL data frame according to the present invention. Figure 5 This is a schematic diagram of the matrix arrangement of micro LEDs. Detailed Implementation
[0021] Before discussing the exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but may also have additional steps not included in the figures. The process can correspond to a method, function, procedure, subroutine, subroutine, etc.
[0022] It should be understood that although the terms "first," "second," etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are used merely to distinguish one unit from another. For example, without departing from the scope of the exemplary embodiments, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0023] The present invention will now be described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.
[0024] Before describing the specific technical solution of this invention, the following explanations are provided for the English abbreviations used in this document and its accompanying drawings: SOF: Start of Frame; Arbitration Field: Arbitration Segment; Control Field: Control Segment; Data Field: Data Segment; CRC Field: Check for frame transmission errors; ACK Field: Acknowledge normal reception; EOF: End of Frame; SDT: Service Data Unit Type.
[0025] FDF: Variable Rate Data Frame Flag; XLF: Extended Length Frame Flag; RRS: Remote Request Replacement; IDE: Identifier Extension.
[0026] For ease of understanding, the inventive concept will be described in its entirety before a detailed description of the embodiments of the present invention: This application provides a projection vehicle lighting electronic system based on CAN XL, which aims to solve the problems of high complexity, high cost and bandwidth waste in the display data transmission scheme of micro LED vehicle lights with tens of thousands of pixels in traditional vehicle lighting applications. The choice of CAN XL data frames for multiplexing display data and control signals is primarily based on the following four aspects: Firstly, micro LEDs with tens of thousands of pixels require a transmission bandwidth of 6Mbps, while CAN XL supports a maximum transmission bandwidth of 20Mbps. This overturns the misconception that higher bandwidth is always better in traditional display data transmission technologies, precisely matching the bandwidth requirements of micro LEDs with tens of thousands of pixels while avoiding bandwidth waste. Secondly, using CAN XL for display data transmission only requires a CAN PHY chip, simplifying system design complexity and reducing system costs. Thirdly, it can directly transmit raw pixel grayscale data without compression, reducing processing latency and burden, and lowering the load and design requirements of the vehicle lighting controller. Fourthly, display data and control signals are identified and parsed based on the service data unit type, variable rate data frame flag, and extended length frame flag. The service data unit type corresponding to the display data is set to a vendor-defined protocol, supporting multiplexing of display data and control signals while ensuring accurate data identification and avoiding conflicts and interference between network devices.
[0027] like Figure 1 As shown, this embodiment provides a projection vehicle lighting electronic system based on CAN XL, which includes a vehicle-side domain controller, a vehicle lighting controller, and a micro LED light panel.
[0028] In some feasible implementations, the body-side domain controller generates headlight control signals and raw headlight display data. Based on the service data unit type and the variable rate data frame flag and extended length frame flag in the arbitration segment, it encapsulates the headlight control signals and raw headlight display data into corresponding CAN XL data frames. These are then transmitted to the headlight controller via the CAN XL data frames. The body-side domain controller is typically a central domain controller or a ZCU (Zone Control Unit) regional controller, which includes a SOC (System-on-a-Chip) module and an MCU (Microcontroller Unit) module.
[0029] Specifically, the headlight control signals include status control signals and fault diagnosis signals, while the raw headlight display data includes the raw grayscale values of the headlight pixels. Each frame of the raw headlight display data corresponds to one display image of the headlight array. When transmitting the display data of micro LED headlights via CAN XL, no data compression and decompression processing is required; the raw grayscale values of the headlight pixels are transmitted directly. This is because micro LEDs have a low resolution, with only one color component, and micro LED headlight pixels are 8-bit. Micro LEDs generally require a refresh rate of more than 30 frames per second, which necessitates a data transmission speed of at least 6 Mbps between the vehicle-side domain controller and the headlight controller. CAN XL supports a maximum transmission bandwidth of 20 Mbps, which can meet the requirements for uncompressed transmission. In traditional technologies, display data is transmitted for all three RGB components, resulting in a data volume far exceeding the transmission bandwidth required by micro LEDs, thus typically involving compression and decompression. Directly transmitting the raw grayscale values of the headlight pixels helps reduce processing latency and workload. In terms of hardware, the transmission of display data is achieved through CAN XL, which only requires a CAN PHY chip. The CAN PHY chip has a maximum of a dozen pins, and its cost is much lower than that of serializers and deserializers in traditional technologies.
[0030] Specifically, such as Figure 2 The diagram shows a schematic of the CAN XL data frame format. In this embodiment, the CAN XL data frames include two types: data frames for vehicle headlight control signals and data frames for raw vehicle headlight display data. Both vehicle headlight control signals and raw vehicle headlight display data are filled into the corresponding data segments of the CAN XL data frames. Each CAN XL data frame can transmit a maximum of 2048 bytes of display data.
[0031] To achieve multiplexing of display data and control signals on the same CAN XL communication link, the control segment of the CAN XL data frame defines a Service Data Unit Type (SDT) to specify the data format within the data segment. The SDT is 8 bits long. The SDT supports Ethernet tunneling, TCP / IP protocol fields, ISO15752-2 fields, CANopen / CANopen FD information, J1939-21 / 22 information, and vendor-defined protocols. When the data segment contains vehicle light control signals, the corresponding SDT is set to the standard CAN control protocol; when the data segment contains raw vehicle light display data, the corresponding SDT is set to the vendor-defined protocol type.
[0032] It should be noted that the original display data of the vehicle lights in this embodiment adopts a vendor-defined protocol type, which ensures the accuracy of data recognition and avoids conflicts and interference between network devices. Each data segment of CAN XL has a clear definition, and devices can only fill in the corresponding data according to the definition, thereby ensuring that all devices on the network protocol can recognize the data frame without conflict. The vendor-defined protocol provides users with a flexible interface, allowing devices to define their own data formats. According to the CAN XL protocol, all devices on the network can recognize that the data segment is of the vendor-defined protocol type, thereby avoiding interference between devices. For example, the vendor-defined protocol type can be defined as a data structure that includes resolution, pixel grayscale data array, and CRC checksum.
[0033] By utilizing the "Vendor-defined Protocol Type" standard field in the CAN XL protocol, a private channel was created for vehicle headlight image data. All devices in the network can accurately identify this as custom data based on this standard field, and non-target devices will actively ignore it, thus avoiding conflicts. The target headlight controller can accurately receive the data and parse it according to the preset private format. This ensures communication reliability while retaining the manufacturer's flexibility to define data details (such as compression and encryption).
[0034] To achieve multiplexing of display data and control signals on the same CAN XL communication link, on the other hand, such as Figure 3The diagram shows the Arbitration Field in a CAN XL data frame. The Arbitration Field includes the Variable Rate Data Frame Flag (FDF), Extended Length Frame Flag (XLF), Remote Request Replacement (RRS), and Identifier Extension (IDE). The Variable Rate Data Frame Flag distinguishes between traditional CAN data frames and CAN FD / CAN XL data frames, while the Extended Length Frame Flag distinguishes between CAN FD and CAN XL data frames. When the Variable Rate Data Frame Flag is dominant (0), the data frame is a traditional CAN data frame; when it is recessive (1), it is either a CAN FD or CAN XL data frame. Similarly, when the Extended Length Frame Flag is dominant (0), the data frame is a CAN FD data frame; and when it is recessive (1), it is a CAN XL data frame. Therefore, CAN XL is compatible with CAN FD. Since the status control signals and fault diagnosis signals of micro LEDs are generally transmitted through the CAN FD protocol, the vehicle lighting control signals, such as status control signals and fault diagnosis signals, can also be transmitted through the CAN XL protocol.
[0035] In some feasible implementations, the headlight controller is used to identify and parse the headlight control signals and original headlight display data in the CAN XL data frame according to the service data unit type, variable rate data frame flag bit, and extended length frame flag bit, and then send the parsed headlight control signals and original headlight display data to the micro LED light board.
[0036] Specifically, such as Figure 4 As shown, based on the service data unit type, variable rate data frame flag, and extended length frame flag, the vehicle headlight control signals and original headlight display data in the CAN XL data frame are identified and parsed, including: Step S1: Determine whether the variable rate data frame flag bit in the arbitration segment of the CAN XL data frame is a dominant bit. If yes, the data frame is a traditional CAN data frame. If no, proceed to step S2. Step S2: Determine whether the extended length frame flag bit in the arbitration segment of the CAN XL data frame is a dominant bit. If yes, the data in the CAN XL data frame is in CAN FD format, and jump to step S3. If no, jump to step S4. Step S3: Parse the headlight control signal according to the CAN FD data frame format; Step S4: Determine whether the service data unit type in the control segment of the CAN XL data frame is a device vendor-defined protocol type. If yes, the data segment of the CAN XL data frame contains the original display data of the vehicle lights. If not, parse it according to the corresponding service data unit type.
[0037] Specifically, such as Figure 1 As shown, the parsed headlight control signals are sent to the micro LED light board via the control interface, and the parsed raw headlight display data is sent to the micro LED light board via the display interface. The display interface is preferably an SPI interface, with a transmission rate typically around 20Mbps. The headlight controller transmits the raw headlight display data to the micro LED light board via the SPI interface. The SPI interface transmission rate is set to be no less than the CAN XL transmission rate to ensure effective transmission of the display data from the CAN XL and avoid frame and data loss. The control interface is preferably a UART interface and / or an IIC interface. Both UART and IIC interfaces are low-speed interfaces, typically with a transmission rate of around 100Kbps. The headlight controller uses the UART and IIC interfaces to initialize, control the status of, and diagnose faults in the micro LED light board. The total bandwidth of the headlight control signals and the raw headlight display data should be lower than the CAN XL transmission bandwidth.
[0038] It's important to note that when display data is transmitted in compressed format, the main control chip of the vehicle body domain controller needs an H.264 / H.265 hardware encoder, and the main control chip of the headlight controller needs an H.264 / H.265 hardware decoder. Chips with H.264 / H.265 codecs are typically complex System-on-a-Chip (SoC) chips, which are expensive and complex, leading to high complexity in board-level system design. When display data is transmitted in raw data format, the vehicle body domain controller does not require a hardware encoder, and the headlight controller does not require a hardware decoder. Both the vehicle body and headlight controllers can choose an MCU as their main control chip. Compared to SoC chips, MCU chips are simpler in cost and function, significantly reducing the complexity and cost of the hardware system design.
[0039] In some feasible implementations, the micro LED light panel is used for lighting function control based on the parsed vehicle light control signals, and for image display based on the parsed original vehicle light display data. For example... Figure 5As shown, the system in this embodiment is applicable to various scenarios of displays with tens of thousands of pixels. Micro LED projection headlights are a typical example. The typical projection resolution of micro LEDs is 320×80, with monochrome pixels and 8-bit data depth per pixel. The transmission bandwidth of CAN XL is slightly higher than that of micro LEDs with tens of thousands of pixels. This allows for precise matching of the transmission bandwidth requirements of micro LEDs with tens of thousands of pixels, ensuring data transmission performance while avoiding bandwidth waste and minimizing system cost.
[0040] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined by the scope of the claims.
Claims
1. A projection vehicle lighting electronic system based on CAN XL, characterized in that, It includes a body-side domain controller, a headlight controller, and a micro LED light panel; The vehicle-side domain controller is used to generate headlight control signals and raw headlight display data. Based on the service data unit type and the variable rate data frame flag and extended length frame flag in the arbitration segment, the headlight control signals and raw headlight display data are encapsulated in corresponding CAN XL data frames. Then, the headlight control signals and raw headlight display data are sent to the headlight controller through the CAN XL data frames. The service data unit type corresponding to the raw headlight display data is a vendor-defined protocol type. The vehicle lighting controller is used to identify and parse the vehicle lighting control signals and original vehicle lighting display data in the CAN XL data frame according to the service data unit type, variable rate data frame flag bit and extended length frame flag bit, and send the parsed vehicle lighting control signals and original vehicle lighting display data to the micro LED light board. The micro LED light panel is used to control the lighting function based on the analyzed vehicle light control signal, and to display images based on the analyzed original vehicle light display data.
2. The projection vehicle lighting electronic system based on CAN XL according to claim 1, characterized in that, When the variable rate data frame flag is dominant, the data frame is a traditional CAN data frame; when the variable rate data frame flag is recessive, the data frame is a CAN FD data frame or a CAN XL data frame.
3. The projection vehicle lighting electronic system based on CAN XL according to claim 1, characterized in that, When the extended length frame flag is dominant, the data frame is a CAN FD data frame; when the extended length frame flag is recessive, the data frame is a CAN XL data frame.
4. The projection vehicle lighting electronic system based on CAN XL according to claim 1, characterized in that, The process of identifying and parsing the vehicle headlight control signals and original headlight display data in the CAN XL data frame based on the service data unit type, variable rate data frame flag, and extended length frame flag includes: Step S1: Determine whether the variable rate data frame flag bit in the arbitration segment of the CAN XL data frame is a dominant bit. If yes, the data frame is a traditional CAN data frame. If no, proceed to step S2. Step S2: Determine whether the extended length frame flag bit in the arbitration segment of the CAN XL data frame is a dominant bit. If yes, the data in the CAN XL data frame is in CAN FD format, and jump to step S3. If no, jump to step S4. Step S3: Parse the headlight control signal according to the CAN FD data frame format; Step S4: Determine whether the service data unit type in the control segment of the CAN XL data frame is a device vendor-defined protocol type. If yes, the data segment of the CAN XL data frame contains the original display data of the vehicle lights. If not, parse it according to the corresponding service data unit type.
5. The projection vehicle lighting electronic system based on CAN XL according to claim 1, characterized in that, The step of sending the parsed headlight control signal and the original headlight display data to the micro LED light board includes: The parsed headlight control signals are sent to the micro LED light board via the control interface, and the parsed original headlight display data is sent to the micro LED light board via the display interface.
6. The projection vehicle lighting electronic system based on CAN XL according to claim 5, characterized in that, The display interface is an SPI interface, which is used for transmitting the original display data of the vehicle lights between the vehicle light controller and the micro LED light board.
7. The projection vehicle lighting electronic system based on CAN XL according to claim 6, characterized in that, The control interface is either a UART interface or an IIC interface. Both the UART interface and the IIC interface are used for transmitting vehicle lighting control signals between the vehicle lighting controller and the micro LED light board.
8. The projection vehicle lighting electronic system based on CAN XL according to claim 1, characterized in that, The original display data of the vehicle lights is the original grayscale value data of the vehicle light pixels.
9. The projection vehicle lighting electronic system based on CAN XL according to claim 1, characterized in that, The vehicle lighting control signals include status control signals and fault diagnosis signals.
10. The projection vehicle lighting electronic system based on CAN XL according to claim 1, characterized in that, The service data unit type corresponding to the vehicle light control signal is the CAN standard control protocol.