Vehicle-mounted TDDI display screen anti-interference electronic design method

Abstract

The invention discloses a vehicle-mounted TDDI display screen anti-interference electronic design method which comprises the following steps: 1) disassembling a complete TDDI vehicle-mounted display screen, removing a structural metal outer frame, and separating the complete TDDI vehicle-mounted display screen into a display screen FOG, a display screen backboard and a backlight module; 2) optimizing the structure of the TDDI vehicle-mounted display screen: performing integrated design on a display screen back plate and a display driving plate, wherein the optimized vehicle-mounted display screen comprises a display screen FOG, an integrated driving plate and a self-made backlight module; 3) optimizing the FOG anti-interference performance of the display screen; 4) optimizing a video architecture: deleting a bridge circuit in the display screen, deleting a video conversion circuit of a display driving board, and selecting a specific SOC to carry out direct drive design on a display screen FOG; and 5) designing the integrated driving board: optimizing a video transmission architecture of the TDDI vehicle-mounted display screen and designing a circuit of the integrated driving board. According to the invention, through the improvement of the structure of the TDDI display screen and the design of LVDS (Low Voltage Differential Signaling) wiring, the anti-interference capability of the vehicle-mounted display screen product is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of intelligent cockpits, and in particular to an anti-interference electronic design method for a vehicle-mounted TDDI display screen. Background Art

[0002] TDDI (Touch and Display Driver Integration) display technology has many outstanding advantages in automotive applications: good display effect, low cost, and thin and light design. This technology is widely used in commercial mobile phones, but it is difficult to apply it in automotive applications. The automotive environment has the characteristics of strong vibration, large temperature changes, and electromagnetic field interference, which puts higher requirements on the stability and durability of TDDI displays. How to maintain the performance and reliability of the screen under these special conditions is an important issue in the current industry.

[0003] The TDDI display solution in the prior art has its own structural problems (such as Figure 1 ), the anti-interference performance is poor. In vehicle-mounted applications, problems such as handheld radio wave interference and ESD screen flicker often occur. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide an anti-interference electronic design method for a vehicle-mounted TDDI display screen. By improving the structure of the TDDI display screen and designing the LVDS wiring, the anti-interference ability of the vehicle-mounted display screen product is effectively improved.

[0005] The object of the present invention is achieved by: a vehicle-mounted TDDI display anti-interference electronic design method, comprising the following steps: 1) Disassemble the complete TDDI vehicle display, remove the structural metal frame, and separate it into the display FOG, display backplane, and backlight module; 2) Optimize the structure of the TDDI vehicle display: integrate the display backplane and the display driver board. The optimized vehicle display includes the display FOG, the integrated driver board and the self-made backlight module; 3) Optimize the FOG anti-interference performance of the display screen; 4) Optimize the video architecture: delete the internal bridge circuit of the display, delete the video conversion circuit of the display driver board, and select a specific SOC to directly drive the display FOG; 5) Integrated driver board design: Optimize the video transmission architecture of the TDDI vehicle display and design the integrated driver board circuit.

[0006] As a further limitation of the present invention, the self-made backlight module in step 2) includes: an LED lamp, a diffusion sheet, a brightness enhancement sheet prism sheet, a reflective sheet and a light guide plate, and the backlight metal shell is directly used as the product shell.

[0007] As a further limitation of the present invention, the step 3) specifically includes: 3-1) Use linear silver paste technology to increase the discharge path, conduct static electricity to the surrounding silver paste, and increase the glass conductive path; 3-2) FPC cable GND shielding layer copper leakage strategy: copper is leaked in the FPC cable grounding shielding layer, and the shortest path is led to the metal casing; copper is leaked at key locations around the back panel of the display screen, and is led to the metal casing behind the display screen through conductive cloth; 3-3) TDDI IC is covered with T-shaped conductive cloth to increase the static discharge path.

[0008] As a further limitation of the present invention, the optimization of the TDDI vehicle display screen video transmission architecture in step 5) specifically includes designing the point-to-point LVDS wiring between the display screen FOG and the SOC, and inputting the video signal from the SOC directly to the display screen TDDI IC in a point-to-point duplex LVDS format to complete the display function.

[0009] As a further limitation of the present invention, the point-to-point LVDS wiring between the display screen FOG and the SOC is designed to specifically include: a) the differential line pairs are of equal length, equal line width W, line spacing g, g ≥ W, the lengths of the same differential line pairs are equal, the lengths of different differential line pairs are as equal as possible, and the length error does not exceed 5 mil; b) Keep the line spacing g between the ground line and the differential line equal, g ≥ 2W, and the width d of all ground lines, d ≥ W should be consistent; c) The differential line pair routing structure is consistent and the symmetrical parallel routing is maintained; d) If differential lines are on the same layer and through holes are to be drilled, both lines need to have through holes; e) The wiring should cross other signal lines vertically to avoid parallel routing; if it is unavoidable, insert a bottom line isolation between LVDS and other signal lines; f) If the wiring is not of equal length, the length needs to be matched by winding, and the winding area should avoid overlapping with other signal lines; g) All LVDS wiring must be located in the middle layer of the FPC and the middle layer of the PCB; the wiring corners must be rounded to maintain the continuity of the wiring width; stay away from other high-speed signal lines; h) Maintain continuity of copper on the back side of the differential line pair and lay solid copper. If it is limited by bending or hardness factors, lay 45° grid copper.

[0010] As a further limitation of the present invention, the design of the unified driver board circuit in step 5) specifically includes: power supply design and TDDI peripheral circuit design; the power supply design includes the design of the display TDDI IC power supply circuit, backlight power supply and display backlight circuit; the TDDI peripheral circuit design specifically includes the design of the source driver SD, the timing control circuit TCON, the gate driver control circuit and the touch controller.

[0011] As a further limitation of the present invention, the integrated driver board circuit also includes an external flash memory, which adopts an external flash memory mode to store the firmware for the touch controller and the initial code of the LCD driver; after the initial code is loaded through the external flash memory, the host sends "sleep" and "display" to turn on the LCD; when static electricity occurs, the host directly reloads the initial code from the flash memory.

[0012] As a further limitation of the present invention, the integrated driver board circuit also uses a dual 120PIN socket for the display screen, and is matched with a TDDI IC to realize loop detection and high-speed matching functions.

[0013] As a further limitation of the present invention, the specific SOC described in step 4) is the Xinchi X9H chip.

[0014] The present invention adopts the above technical solution, and has the following beneficial effects compared with the prior art: 1) By optimizing the structure of the TDDI vehicle-mounted display screen and the FOG anti-interference performance of the display screen, the anti-interference performance of the TDDI display screen technology in vehicle-mounted applications is improved; the performance and reliability of the screen are guaranteed in the environment of strong vibration, large temperature change and electromagnetic field interference of the car. 2) The design of LVDS wiring reduces signal noise. The video signal is directly output from the SOC to the TDDI IC in the P2P Dual LVDS format, which reduces the signal conversion and processing in the intermediate links, reduces the attenuation and distortion of the signal during the conversion process, and thus reduces the generation of noise. Reduced electromagnetic radiation, direct transmission and integrated design reduce the electromagnetic radiation source in the system, thereby reducing the risk of interference and interference to other chips; the system integrated design merges the original two PCBAs into one PCBA, simplifies the system architecture, reduces the number of conversion chips, reduces the overall complexity and failure rate of the system, and improves the anti-interference performance of the system; simplifies high-speed wiring, and reduces the high-speed video signal from three conversions to one conversion, reduces the crosstalk and coupling effects between signal lines, and further improves the integrity and anti-interference ability of the signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of TDDI vehicle display module in the prior art.

[0016] Figure 2Schematic diagram of the TDDI vehicle-mounted display screen module of the present invention.

[0017] Figure 3 Schematic diagram of TDDI vehicle display module solution in the prior art.

[0018] Figure 4 Schematic diagram of the TDDI vehicle display optimization solution of the present invention.

[0019] Figure 5 The block diagram of the integrated driver board design of the present invention. DETAILED DESCRIPTION

[0020] A method for designing anti-interference electronics for a vehicle-mounted TDDI display screen comprises the following steps: 1) Disassemble the complete TDDI car display, remove the structural metal frame, and separate it into display FOG, display backplane, and backlight module, such as Figure 2 shown.

[0021] 2) Optimize the structure of the TDDI vehicle display: integrate the display backplane and the display driver board into one design. The optimized vehicle display includes the display FOG, the integrated driver board and the self-made backlight module; the self-made backlight module includes: LED lights, diffusers, brightening prisms, reflectors and light guide plates. The backlight metal shell is directly used as the product shell.

[0022] 3) Optimize the FOG anti-interference performance of the display screen; 3-1) Adopt linear silver paste process to increase the discharge path, conduct static electricity to the surrounding silver paste, increase the glass conductive path, and be more conducive to the discharge of static electricity; 3-2) FPC cable GND shielding layer copper leakage strategy: copper is leaked in the FPC cable grounding shielding layer, and the shortest path is led to the metal casing; copper is leaked at key locations around the back panel of the display screen, and is led to the metal casing behind the display screen through conductive cloth; 3-3) TDDI IC is covered with T-shaped conductive cloth to increase the static discharge path.

[0023] like Figure 3 As shown, in the prior art, the TDDI display screen module is an EDP interface, and the video signal is output from the SOC as a MultiDrop Dual LVDS (multi-branch duplex LVDS) signal, which is converted into an EDP signal through a video converter and connected to the display screen; inside the display screen, the video bridge chip enters from the EDP interface, and is converted into a P2P Dual LVDS (point-to-point duplex LVDS) and enters the display screen TDDI IC to complete the display function; 4) If Figure 4As shown in the figure, the video architecture is optimized: the internal bridge circuit of the display is deleted, the video conversion circuit of the display driver board is deleted, and a specific SOC is selected to directly drive the display FOG; the specific SOC uses the CoreChi X9H chip, the specific model is X9669-AHFAA.

[0024] 5) Unified driver board design: optimize the video transmission architecture of the TDDI vehicle display and design the unified driver board circuit; optimize the video transmission architecture of the TDDI vehicle display, including designing the point-to-point LVDS wiring between the display FOG and SOC, and inputting the video signal from the SOC directly to the display TDDI IC in a point-to-point duplex LVDS format to complete the display function; Design of point-to-point LVDS wiring (P2P Dual LVDS) between the display screen FOG and SOC specifically includes: a) The differential line pairs are of equal length, equal line width W, line spacing g, g ≥ W, the lengths of the same differential line pairs are equal, the lengths of different differential line pairs are as equal as possible, and the length error does not exceed 5mil; b) Keep the line spacing g between the ground line and the differential line equal, g ≥ 2W, and the width d of all ground lines, d ≥ W should be consistent; c) The differential line pair routing structure is consistent and the symmetrical parallel routing is maintained; d) If differential lines are on the same layer and through holes are to be drilled, both lines need to have through holes; e) The wiring should cross other signal lines vertically to avoid parallel routing; if it is unavoidable, insert a bottom line isolation between LVDS and other signal lines; f) If the wiring is not of equal length, the length needs to be matched by winding, and the winding area should avoid overlapping with other signal lines; g) All LVDS wiring must be located in the middle layer of the FPC and the middle layer of the PCB; the wiring corners must be rounded to maintain the continuity of the wiring width; stay away from other high-speed signal lines; h) Maintain continuity of copper on the back side of the differential line pair and lay solid copper. If it is limited by bending or hardness factors, lay 45° grid copper.

[0025] like Figure 5 As shown, the design of the integrated driver board circuit specifically includes: power supply design and TDDI peripheral circuit design; the power supply design includes the design of the display TDDI IC power supply circuit, backlight power supply and display backlight circuit; the TDDI peripheral circuit design specifically includes the design of the source driver SD, the timing control circuit TCON, the gate driver control circuit and the touch controller.

[0026] The Heyi driver board circuit also includes an external flash memory, which uses an external flash memory mode to store the firmware for the touch controller and the initial code of the LCD driver. After the initial code is loaded through the external flash memory, the host sends "sleep" and "display" to turn on the LCD. When static electricity occurs, the host directly reloads the initial code from the flash memory. For high-definition display screens 2560*1440@60fps, the upper limit frequency of LVDS data transmission cannot exceed 140MHz; it is generally maintained below 120MHz. Considering that the all-in-one board cannot be bound, a dual 120PIN socket connection solution is required. The all-in-one driver board circuit also uses a dual 120PIN socket for the display screen, which is matched with TDDI IC to realize loop detection and high-speed matching functions.

[0027] The present invention provides an anti-interference electronic design method for a vehicle-mounted TDDI display screen. By optimizing the structure of the TDDI vehicle-mounted display screen and the FOG anti-interference performance of the display screen, the anti-interference performance of the TDDI display screen technology in vehicle-mounted applications is improved; the performance and reliability of the screen are guaranteed in the environment of strong vibration, large temperature change and electromagnetic field interference of the car. The design of LVDS wiring reduces signal noise, reduces electromagnetic radiation, and reduces the risk of interference to other chips and being interfered with; the system integration design merges the original two PCBAs into one PCBA, simplifies the system architecture, reduces the number of conversion chips, reduces the overall complexity and failure rate of the system, and improves the anti-interference performance of the system; simplifies high-speed wiring, reduces high-speed video signals from three conversions to one conversion, reduces crosstalk and coupling effects between signal lines, and further improves signal integrity and anti-interference capabilities.

[0028] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A method for designing anti-interference electronics for a vehicle-mounted TDDI display screen, characterized in that: The following steps are involved: 1) Disassemble the complete TDDI vehicle display, remove the structural metal frame, and separate it into the display FOG, display backplane, and backlight module; 2) Optimize the structure of the TDDI vehicle display: integrate the display backplane and the display driver board. The optimized vehicle display includes the display FOG, the integrated driver board and the self-made backlight module; 3) Optimize the FOG anti-interference performance of the display screen; 4) Optimize the video architecture: delete the internal bridge circuit of the display, delete the video conversion circuit of the display driver board, and select a specific SOC to directly drive the display FOG; 5) Integrated driver board design: Optimize the video transmission architecture of the TDDI vehicle display and design the integrated driver board circuit.

2. The anti-interference electronic design method of a vehicle-mounted TDDI display screen according to claim 1 is characterized in that: The self-made backlight module described in step 2) includes: LED lamp, diffusion sheet, brightness enhancement sheet prism sheet, reflective sheet and light guide plate, and the backlight metal shell is directly used as the product shell.

3. The anti-interference electronic design method of a vehicle-mounted TDDI display screen according to claim 1 is characterized in that: The step 3) specifically includes: 3-1) Use linear silver paste technology to increase the discharge path, conduct static electricity to the surrounding silver paste, and increase the glass conductive path; 3-2) FPC cable GND shielding layer copper leakage strategy: copper is leaked in the FPC cable grounding shielding layer, and the shortest path is led to the metal casing; copper is leaked at key locations around the back panel of the display screen, and is led to the metal casing behind the display screen through conductive cloth; 3-3) TDDI IC is covered with T-shaped conductive cloth to increase the static discharge path.

4. The anti-interference electronic design method of a vehicle-mounted TDDI display screen according to claim 1 is characterized in that: The optimization of the TDDI vehicle display video transmission architecture described in step 5) specifically includes designing the point-to-point LVDS wiring between the display FOG and the SOC, and inputting the video signal from the SOC directly to the display TDDI IC in a point-to-point duplex LVDS format to complete the display function.

5. The anti-interference electronic design method of a vehicle-mounted TDDI display screen according to claim 4 is characterized in that: The point-to-point LVDS wiring design between the display screen FOG and the SOC specifically includes: a) the differential line pairs are of equal length, equal line width W, line spacing g, g ≥ W, the lengths of the same differential line pairs are equal, the lengths of different differential line pairs are as equal as possible, and the length error does not exceed 5 mil; b) Keep the line spacing g between the ground line and the differential line equal, g ≥ 2W, and the width d of all ground lines, d ≥ W should be consistent; c) The differential line pair routing structure is consistent and the symmetrical parallel routing is maintained; d) If differential lines are on the same layer and through holes are to be drilled, both lines need to have through holes; e) The wiring should cross other signal lines vertically to avoid parallel routing; if it is unavoidable, insert a bottom line isolation between LVDS and other signal lines; f) If the wiring is not of equal length, the length needs to be matched by winding, and the winding area should avoid overlapping with other signal lines; g) All LVDS wiring must be located in the middle layer of the FPC and the middle layer of the PCB; the wiring corners must be rounded to maintain the continuity of the wiring width; stay away from other high-speed signal lines; h) Maintain continuity of copper on the back side of the differential line pair and lay solid copper. If it is limited by bending or hardness factors, lay 45° grid copper.

6. The anti-interference electronic design method of a vehicle-mounted TDDI display screen according to claim 1 is characterized in that: The design of the integrated driver board circuit described in step 5) specifically includes: power supply design and TDDI peripheral circuit design; the power supply design includes the design of the display TDDI IC power supply circuit, backlight power supply and display backlight circuit; the TDDI peripheral circuit design specifically includes the design of the source driver SD, timing control circuit TCON, gate driver control circuit and touch controller.

7. The anti-interference electronic design method of a vehicle-mounted TDDI display screen according to claim 6 is characterized in that: The integrated driver board circuit also includes an external flash memory, which uses an external flash memory mode to store the firmware for the touch controller and the initial code of the LCD driver; after the initial code is loaded through the external flash memory, the host sends "sleep" and "display" to turn on the LCD; when static electricity occurs, the host directly reloads the initial code from the flash memory.

8. The anti-interference electronic design method for a vehicle-mounted TDDI display screen according to claim 6, characterized in that: The integrated driver board circuit also uses a dual 120PIN socket for the display screen, and is matched with a TDDI IC to realize loop detection and high-speed matching functions.

9. The anti-interference electronic design method of a vehicle-mounted TDDI display screen according to claim 1, characterized in that: The specific SOC described in step 4) uses the CoreChi X9H chip.

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