Lamp panel system based on electrically controllable deep color film and control method thereof

Abstract

The invention provides a lamp panel system based on an electrically controllable deep color film and a control method of the lamp panel system, and belongs to the technical field of LED illumination and display. The technical problems to be solved are that an existing lamp panel flickers at a low gray scale, is inconsistent in ink color, is high in power consumption, is high in heat, is delayed in response, and is poor in lamp bead adaptability. According to the technical scheme, the lamp panel comprises a lamp panel, a driving circuit, an electrically-controllable deep-color film, a film control circuit and a main control unit, the electrically-controllable deep-color film is arranged on a light emitting path of the lamp panel and electrically connected with the film control circuit, the input end of the lamp panel is electrically connected with the output end of the driving circuit, and the output end of the driving circuit is electrically connected with the main control unit. The driving circuit and the thin film control circuit are electrically connected with the main control unit, the main control unit is used for controlling the lamp panel through the driving circuit, controlling the electrically-controllable deep-color thin film through the thin film control circuit and receiving feedback of the driving circuit and the thin film control circuit, and the electrically-controllable deep-color thin film shows a deep color when power is off; the backlight module is applied to the field of outdoor display and vehicle-mounted backlight.

Description

Technical Field

[0001] This application relates to the field of LED lighting and display technology, and in particular to a lamp board system based on an electrically controllable dark film and its control method. Background Technology

[0002] Due to their advantages such as high integration, uniform light emission, and controllable cost, LED panels have been widely used in indoor lighting, outdoor displays, and automotive backlighting. However, existing LED panel technology faces four major industry pain points that urgently need to be addressed: 1. Low grayscale flicker problem: Mainstream PWM (Pulse Width Modulation) dimming technology has limitations in low grayscale (brightness ≤ 50 cd / m²) flicker. 2 1. **Failure to meet visual requirements:** When the PWM duty cycle is ≤10%, the high-frequency switching causes noticeable flickering that is easily perceived by the human eye, leading to visual fatigue with prolonged viewing. This is particularly unacceptable for high-end applications such as automotive and medical settings, where visual health requirements are not met. 2. **Inconsistent color:** Existing light boards often use FR4 fiberglass boards as the substrate, which are naturally pale yellow. When power is off, the substrate color differs significantly from the LED chip encapsulation adhesive color, resulting in "white spots" and "color differences" when multiple modules are spliced ​​together. The color uniformity ΔE≥3 fails to meet the aesthetic requirements of high-end products. 3. **High power consumption and high heat issues:** To improve brightness, traditional solutions require increasing the drive current (≥300mA) or using larger LED chips (≥0.5mm²). 2 This results in a surface temperature of ≥85℃ for the lamp board, creating a "hot screen" effect. This not only reduces luminous efficacy (≤100lm / W) but also accelerates LED light decay (≥20% light decay after 5000 hours), affecting product reliability. 4. Response delay: Existing control solutions use MCU as the main controller, with a thin-film response time ≥5ms and an overall dimming response ≥10ms, which cannot meet the real-time control requirements of scenarios such as automotive displays and high-speed optical equipment. 5. Poor adaptability of LED configuration: The number of LEDs in traditional lamp boards is fixed and cannot be flexibly adjusted according to the dot pitch requirements of different application scenarios, resulting in insufficient light uniformity or cost waste.

[0003] To address the aforementioned issues, existing technologies mostly offer fragmented solutions for single problems: for example, using high-frequency PWM (≥50kHz) to improve flicker, but this increases the complexity of the drive circuit; using a black coating to cover the substrate to solve aesthetic problems, but this reduces luminous efficacy by ≥15%; using heat sinks to increase heat dissipation area, but this increases product size and cost; using high-speed MCUs to improve response speed, but the logic delay is still ≥100ns, making nanosecond-level control impossible; and the fixed number of LEDs results in poor adaptability. These solutions are mutually restrictive and cannot fundamentally achieve synergistic optimization of multiple performance aspects. Therefore, there is an urgent need in this field for a systematic and comprehensive solution. Summary of the Invention

[0004] To address the aforementioned technical problems, this application proposes a light panel system based on an electrically controllable dark film and its control method.

[0005] The technical solution adopted in this application is as follows: a lamp board system based on an electrically controllable dark film, comprising a lamp board, a driving circuit, an electrically controllable dark film, a film control circuit, and a main control unit. The electrically controllable dark film is disposed on the light output path of the lamp board. The electrically controllable dark film is electrically connected to the film control circuit. The input terminal of the lamp board is electrically connected to the output terminal of the driving circuit. The driving circuit and the film control circuit are respectively electrically connected to the main control unit. The main control unit is used to control the lamp board through the driving circuit, control the electrically controllable dark film through the film control circuit, and receive feedback from the driving circuit and the film control circuit. The electrically controllable dark film appears dark or pure black when there is no external electric drive.

[0006] Furthermore, the lamp panel includes a substrate, which is an FR4 epoxy resin glass fiber cloth laminate.

[0007] Furthermore, the substrate surface is coated with copper.

[0008] Furthermore, the electrically controllable dark film is a high-speed response electrochromic film that remains black when powered off or a nanoscale PDLC film.

[0009] Furthermore, a protective film is provided on the surface of the electrically controllable dark film.

[0010] Furthermore, the main control unit is an FPGA chip.

[0011] Furthermore, a control method based on an electrically controllable dark film light panel system, employing the electrically controllable dark film light panel system as described above, includes the following steps: Step 1: The main control unit controls the lamp board to work with multiple different PWM duty cycles. The main control unit controls the transmittance of the electrically controllable dark film. A photometer is used to measure and record the final output brightness under different transmittances. The corresponding relationship data of multiple sets of data is established, and then a pre-stored calibration database is established. Step 2: The main control unit calculates and outputs a combination of control signals based on the received target brightness command and the pre-stored calibration database. The combination of control signals includes the PWM duty cycle signal of the lamp board and the transmittance signal of the electrically controllable dark film. Step 3: The main control unit, according to the control signal combination, coordinates the PWM duty cycle of the lamp board and the light transmittance of the electrically controllable dark film to achieve the target brightness output; Step 4: When the lamp panel needs to be turned off in a low grayscale state, first reduce the light transmittance of the electrically controllable dark film, and then turn off the lamp panel after a delay to achieve low grayscale flicker suppression.

[0012] Furthermore, in step two, the main control unit outputs multiple combinations of control signals, each of which ensures that the operating current of the lamp board is not less than 60% of the rated current.

[0013] Furthermore, in step three, the main control unit selects a control signal combination with a high PWM duty cycle and low light transmittance from among the multiple control signal combinations, and controls the PWM duty cycle of the lamp board and the light transmittance of the electrically controllable dark film according to the control signal combination.

[0014] The advantages of this application compared to existing technologies are as follows: This application provides a light panel system and its control method based on an electrically controllable dark film. Through a high-speed hardware architecture and a set of nanosecond-level control logic, it simultaneously solves five major problems: low grayscale flicker, inconsistent substrate ink color, high power consumption and high heat, response delay, and poor LED configuration compatibility, without requiring additional structures. It achieves a significant performance improvement: luminous efficacy ≥130lm / W, an improvement of ≥30% compared to traditional solutions; light panel surface temperature ≤60℃; light decay ≤10% after 5000 hours; product lifespan extension ≥50%; imperceptible low grayscale flicker, conforming to the GB / T20145-2006 visual health standard; and a total system response time ≤1μs, meeting the needs of high-speed application scenarios. The light panel system presents a pure black appearance after power failure, completely covering the pale yellow of the substrate. The uniformity of ink color in module splicing ΔE ≤1.5, meeting the appearance requirements of high-end products. The number of LEDs can be flexibly configured according to the dot pitch to adapt to different resolutions or uniformity requirements, avoiding resource waste. It uses small-sized LED chips (0.2-0.3mm). 2 Achieving the same brightness while reducing chip costs by ≥20%; eliminating the need for additional heat dissipation structures and light-shielding coatings, resulting in a ≥15% reduction in overall cost; compatible with existing lamp board production lines, requiring only the addition of a thin-film bonding process and an upgrade to the FPGA main control unit, making it easy to mass-produce and promote. Attached Figure Description

[0015] The following description, in conjunction with the accompanying drawings, further illustrates this application: Figure 1 This is a schematic diagram of the structure of the lamp panel in this application; Figure 2 This is a structural block diagram of the lamp board system in this application; Figure 3 This is a flowchart of the control method for the lamp board system in this application; In the diagram: 1 is the protective film, 2 is the electrically controllable dark film, and 3 is the light panel. Detailed Implementation

[0016] like Figures 1 to 3 As shown, this application provides a light panel system and its control method based on an electrically controllable dark film. The light panel system includes a light panel 3, a driving circuit, an electrically controllable dark film 2, a film control circuit, and a main control unit. The electrically controllable dark film 2 is disposed on the light output path of the light panel 3. The electrically controllable dark film 2 is electrically connected to the film control circuit. The input terminal of the light panel 3 is electrically connected to the output terminal of the driving circuit. The driving circuit and the film control circuit are respectively electrically connected to the main control unit. The main control unit is used to control the light panel 3 through the driving circuit, control the electrically controllable dark film 2 through the film control circuit, and receive feedback from the driving circuit and the film control circuit. The electrically controllable dark film 2 presents a dark or pure black state when there is no external electrical drive. The light panel 3 includes a substrate, which is an FR4 epoxy resin glass fiber cloth laminate with copper plating on its surface. The electrically controllable dark film 2 is a high-speed response electrochromic film that remains black when powered off or a nanoscale PDLC film, and a protective film 1 is provided on the surface of the electrically controllable dark film 2. The main control unit is an FPGA chip.

[0017] like Figure 1 , Figure 2 As shown, in practical operation, the lamp board 3 adopts an integrated LED chip packaging structure and uses an FR4 epoxy resin glass fiber cloth laminate PCB substrate as the supporting base. The substrate has a dielectric constant of 4.2-4.8, a thermal conductivity of ≥1.2W / (m·K), and a thickness of 1.6-2.0mm. The substrate surface is copper-clad with a thickness of 35-70μm to improve heat dissipation efficiency. LED chips are arrayed on the substrate surface, with the chip spacing configured according to display accuracy requirements. Signal interference is reduced by optimizing the wiring, ensuring color uniformity. In this application, a spacing of 0.2-0.4mm is used. 2 High-speed response LED chips (switching time ≤ 100ns), the number of LEDs N is flexibly determined according to the target point spacing, and the calculation formula is: N = (Length of luminous surface / P) × (Width of luminous surface / P); Where P is the dot pitch and N is the number of LEDs, the calculation error is ≤ ±1 LED, the LEDs are evenly distributed, the spacing between adjacent LEDs is consistent with the dot pitch P, and the uniformity error of the light-emitting surface is ≤ ±3%. For example, if the light-emitting surface is 300mm × 150mm, then when the dot pitch P is 5mm, the number of LEDs N = (300 / 5) × (150 / 5) = 1800 LEDs.

[0018] An electrically controllable dark film 2 is stacked on the light-emitting path of the lamp board 3. A high-speed electrochromic film that remains black when powered off or a nano-scale PDLC film is selected as the electrically controllable dark film 2. The thickness is 0.1-0.3 mm, the transmittance is adjustable from 1% to 85%, the response time is ≤500 ns, the L* value is ≤5 (pure black) in the power-off state, and the haze is ≤2% in the power-on state. It is bonded to the lamp board 3 through a low-refractive-index optical adhesive layer (refractive index 1.52, transmittance 99%), with a bonding gap ≤0.1 mm to avoid light refraction loss. The electrically controllable dark film 2 is used to cover the pale yellow color of the substrate of the lamp board 3 and the LED chip solder joints when the system is powered off, so that the system appearance presents a uniform dark color, i.e., an L* value ≤8, resulting in a color difference ΔE ≤1.5 when modules are spliced, eliminating the need for additional light-shielding structures or coatings. The transmittance of the electrically controllable dark film 2 is continuously adjustable in response to a 0-36V DC or AC signal within the range of 1%-85%. The surface of the electrically controllable dark film 2 is coated with a protective film 1, which effectively resists external damage such as bumps and friction, extending the outdoor service life of the light panel 3.

[0019] The thin-film control circuit includes a high-speed DC / AC conversion module (using GaN devices, switching frequency ≥1MHz, input 12-24V, output 0-36V), a nanosecond-level voltage regulation unit (based on high-speed operational amplifier AD8001, slew rate ≥1000V / μs), and a real-time feedback detection circuit (using high-speed photodiode S13360, response time ≤10ns), which monitors the transmittance of the thin film in real time and feeds it back to the main control unit, with an adjustment accuracy ≤±0.1V and a response delay ≤100ns.

[0020] The main control unit uses an FPGA chip (such as the Xilinx Artix-7 series, logic delay ≤10ns), and integrates a high-speed ADC sampling module (sampling rate ≥1GSps, accuracy 14-bit), a high-frequency PWM generation module (frequency 10kHz-100kHz, duty cycle adjustment step 0.1%), and an LVDS high-speed interface (transmission rate ≥10Gbps). The main control unit is responsible for receiving target brightness commands, querying the calibration database, and outputting coordinated control signals. Its computational delay is ≤10ns, and the total system response time is ≤1μs. The main control unit is connected to the driving circuit of the lamp board 3 and the thin-film control circuit via the LVDS high-speed interface or PWM interface. By coordinating the emission state of the lamp board 3 and the transmittance of the electrically controllable dark film 2, the main control unit achieves the final light emission characteristics adjustment of the system with a ns-level response. In the embodiments of this application, high-transmittance silicone with a transmittance ≥95% is used to encapsulate the lamp board, with an encapsulation thickness of 0.3-0.5mm to prevent the lamp chip solder joints from being exposed.

[0021] like Figure 3As shown, a control method based on an electrically controllable dark film lamp panel system is described. The method employs the electrically controllable dark film lamp panel system as described above, and specifically includes the following steps: Step 1: After receiving the target brightness command, the main control unit executes the initialization and calibration sub-process, which includes the following steps: 1. The main control unit controls the lamp board 3 to work with multiple different PWM duty cycles. In the embodiments of this application, the preferred PWM duty cycles are 30%, 60%, and 100%. 2. The main control unit controls the thin film control circuit to scan the light transmittance of the electrically controllable dark film 2 in 5% increments, with the light transmittance ranging from 1% to 85%. 3. Response time ≤ 10μs, accuracy ±1cd / m 2 A high-speed, high-precision photometer is used to measure and record the final output brightness of light with different transmittances under standard test conditions (25℃, no reflection, distance 50cm). A correspondence between no fewer than 51 sets of data is established, and a pre-stored calibration database is created and stored in the high-speed buffer memory of the main control unit. The total time for the above initialization steps is ≤30s.

[0022] Step 2: Perform a command validity check, i.e., determine whether the target brightness is within the system's supported effective range (10-10000 cd / m²). 2 Within this scope, avoid invalid commands that could cause system errors: If the brightness is between 10-10000 cd / m² 2 If the value is within the specified range, it indicates that the target brightness command is valid, meaning that the target brightness meets the luminous capability of lamp panel 3 (after configuring the number of LEDs according to the dot pitch, the maximum brightness can reach 10000 cd / m²). 2 The main control unit then calculates and outputs multiple control signal combinations based on the received target brightness command and the pre-stored calibration database. These control signal combinations include the PWM duty cycle signal of the lamp board 3 (frequency range of 10kHz-100kHz, accuracy ±0.1%) and the transmittance signal of the electrically controllable dark film 2. From the output control signal combinations, the unit selects a combination that allows the lamp board 3 to operate at a higher PWM duty cycle (≥30%) than traditional single PWM dimming schemes and maintains the lamp board 3's operating current within the 60%-100% range of its rated current. This achieves high luminous efficacy (≥130lm / W) and cold screen operation (lamp board 3 surface temperature ≤60℃). If the brightness is <10 cd / m 2 (Below the minimum brightness corresponding to the lowest transmittance of the film) or >10000 cd / m 2If the maximum light emission capacity exceeds the rated power of COB lamp board 3, an error message will be output (which can be fed back to the upper-level system through the FPGA's I / O port), while maintaining the current working state to avoid sudden brightness changes affecting the user experience.

[0023] Step 3: The main control unit coordinates the PWM duty cycle of the lamp board 3 and the transmittance of the electrically controllable dark film 2 according to the control signal combination to achieve the target brightness output at the nanosecond level; Step 4: After the coordinated adjustment is completed, perform a brightness feedback detection operation. After the brightness feedback detection is completed, determine whether a low grayscale shutdown operation needs to be performed: If the target brightness is ≤50 cd / m² 2 When the system receives a "turn off light" command (such as when the user turns off the device or when the scene needs to be turned off), the main control unit adopts the "film turns off first, light source turns off later" timing sequence to perform ns-level low grayscale flicker suppression operation. That is, the main control unit sends a film turn-off command through the LVDS interface (delay ≤10ns). The film control circuit responds within 100ns and reduces the transmittance of the electrically controllable dark film 2 to ≤2% (the response time of this step is ≤500ns). After the transmittance drops to the required value, there is a delay of 100-500ns, and then the drive circuit of the lamp board 3 is controlled to turn off the PWM signal to avoid flickering caused by sudden brightness changes. At this time, the flickering frequency is ≤20Hz, and the human eye does not perceive flickering. The total time of the entire turn-off process is ≤1.1μs. If the target brightness cannot be ≤50 cd / m² at the same time 2 If the system receives a "turn off light output" command, then the accuracy of the actual brightness after coordinated adjustment is verified, that is, whether the error between the actual measured brightness and the target brightness is ≤ ±3 cd / m². 2 If the error is ≤ ±3cd / m 2 If the brightness accuracy requirements of high-end displays or lighting are met, the current control parameters (PWM duty cycle and thin film transmittance) will be maintained, and the system will enter a stable operating state; if the error is > ±3cd / m 2 If the error message indicates that the adjustment deviation may be caused by power fluctuations or environmental interference, the system will return to the database query step, rematch the optimal control combination, perform secondary adjustment, and form a closed-loop control.

[0024] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A light panel system based on an electrically controllable dark film, characterized in that: The device includes a lamp board (3), a driving circuit, an electrically controllable dark film (2), a film control circuit, and a main control unit. The electrically controllable dark film (2) is disposed on the light output path of the lamp board (3). The electrically controllable dark film (2) is electrically connected to the film control circuit. The input terminal of the lamp board (3) is electrically connected to the output terminal of the driving circuit. The driving circuit and the film control circuit are respectively electrically connected to the main control unit. The main control unit is used to control the lamp board (3) through the driving circuit, control the electrically controllable dark film (2) through the film control circuit, and receive feedback from the driving circuit and the film control circuit. The electrically controllable dark film (2) presents a dark or pure black state when there is no external electric drive.

2. The light panel system based on an electrically controllable dark film according to claim 1, characterized in that: The lamp panel (3) includes a substrate, which is an FR4 epoxy resin glass fiber cloth laminate.

3. A light panel system based on an electrically controllable dark film according to claim 2, characterized in that: The substrate surface is coated with copper.

4. A light panel system based on an electrically controllable dark film according to claim 3, characterized in that: The electrically controllable dark film (2) is a high-speed response electrochromic film that remains black when powered off or a nanoscale PDLC film.

5. A light panel system based on an electrically controllable dark film according to claim 3 or 4, characterized in that: The surface of the electrically controllable dark film (2) is provided with a protective film (1).

6. A light panel system based on an electrically controllable dark film according to claim 5, characterized in that: The main control unit is an FPGA chip.

7. A control method for an electrically controllable dark film light panel system, employing the electrically controllable dark film light panel system as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: The main control unit controls the lamp board (3) to work with multiple different PWM duty cycles. The main control unit controls the transmittance of the electrically controllable dark film (2), uses a photometer to measure and record the final light output brightness under different transmittance, establishes the corresponding relationship data of multiple sets of data, and then establishes a pre-stored calibration database. Step 2: The main control unit calculates and outputs a combination of control signals based on the received target brightness command and the pre-stored calibration database. The combination of control signals includes the PWM duty cycle signal of the lamp board (3) and the transmittance signal of the electrically controllable dark film (2). Step 3: The main control unit, according to the control signal combination, coordinates the PWM duty cycle of the lamp board (3) and the transmittance of the electrically controllable dark film (2) to achieve the target brightness output; Step 4: When the lamp panel (3) needs to be turned off in a low grayscale state, first reduce the transmittance of the electrically controllable dark film (2), and then turn off the lamp panel (3) after a delay to achieve low grayscale flicker suppression.

8. The control method for a controllable dark film light panel system according to claim 7, characterized in that: In step two, the main control unit outputs multiple combinations of control signals, each of which ensures that the operating current of the lamp board (3) is not less than 60% of the rated current.

9. A control method for a controllable dark film light panel system according to claim 8, characterized in that: In step three, the main control unit selects a control signal combination with high PWM duty cycle and low transmittance from multiple control signal combinations, and controls the PWM duty cycle of the lamp board (3) and the transmittance of the electrically controllable dark film (2) according to the control signal combination.

Images