White balance compensation method and system for LED display panel

Abstract

The present invention relates to the technical field of electro-luminescence display. Disclosed are a white balance compensation method and system for an LED display panel. The method comprises: using an FPGA chip to drive an LED full-color display panel; performing frequency division on a crystal oscillator by means of the FPGA chip to obtain three synchronous clocks for respectively controlling a red LED display driver subsystem, a green LED display driver subsystem, and a blue LED display driver subsystem; a single-chip microcomputer acquiring a current environment temperature from a temperature sensor and transmitting temperature information to the FPGA chip, and the FPGA chip adjusting column strobe time for the first time on the basis of the environment temperature and different relative brightness of primary color LEDs under different temperature conditions; and the single-chip microcomputer acquiring the environment temperature every other column strobe time adjustment cycle and transmitting the temperature information to the FPGA chip, and the FPGA chip adjusting the column strobe time once every other column strobe time adjustment cycle on the basis of the current environment temperature and different relative brightness of the primary color LEDs under different temperature conditions. The present invention automatically realizes white balance by using progressive scanning technology based on dynamic adjustment of column strobe time.

Description

A white balance compensation method and system for LED display panel Technical Field

[0001] The present invention belongs to the technical field of electroluminescent display, and in particular relates to a white balance compensation method and system for an LED display panel. Background Art

[0002] Certain substances can emit light when driven by a certain voltage. This phenomenon, in which electrical energy is directly converted into visible light, is called electroluminescence (EL). Broadly speaking, EL includes not only light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), and electroluminescent displays (ELDs), but also semiconductor lasers. LEDs and OLEDs are "injection-type" EL displays, differing primarily in that LEDs use inorganic materials, while OLEDs use organic materials.

[0003] With the development of science and technology and the progress of society, LED large-screen displays, as an important branch of new display technologies, are developing rapidly and their application areas are constantly expanding. Among them, full-color LED displays are widely used in the service industry, finance, transportation, and other fields due to their advantages such as large size, high brightness, and seamless splicing. The color of each pixel on an LED full-color display is a combination of red, green, and blue LEDs with grayscale levels in a specified ratio. Therefore, the main characteristics of the white balance of LED displays are related to the brightness and chromaticity of the red, green, and blue LEDs. Stabilizing the matching ratio parameters of each primary color not only ensures the correct reproduction of the display's white balance, but also accurately restores the color tone of the displayed image. Although LED display products have many advantages, the light emission of LEDs is easily affected by many internal and external factors. For example, the temperature characteristics and attenuation characteristics of the LED, as well as the power supply of the driving circuit, can cause the brightness of each primary color to change over time, resulting in deviations in the brightness and chromaticity of the white balance.

[0004] The luminous flux of LED gradually declines with the accumulation of lighting time. The current research standard often regards the end of the life of the LED light source when the luminous flux decays to 70% (or 50%) of the initial value at the factory.

[0005] Regarding the causes of LED light decay, Georgiy Bobashev's team experimentally discovered that within the first 1000 hours of operation under low-stress conditions, the luminous flux of LEDs does not follow exponential decay. Researchers such as Rossi have shown that the primary cause of LED degradation is non-radiative recombination caused by carrier mobility defects, but they have not analyzed the impact of current, temperature, and other parameters on light decay. Narendran's research indicates that the junction temperature of an LED chip significantly impacts its operating lifespan; higher junction temperatures lead to faster LED light decay. However, this research lacks a comprehensive mathematical model linking light decay rate and junction temperature, making it theoretically unconvincing.

[0006] In terms of light decay compensation, Guo Jin and others obtained the light decay characteristic curve from the LED data sheet and designed a light decay compensated LED driver controller. The LED controller combines the light decay curve with the predetermined output current value, maintaining a certain degree of constancy in the light source's output luminous flux and achieving light decay compensation. However, LED light decay is affected by multiple factors, and the light decay characteristic curve only considers the LED junction temperature. While it can achieve light decay compensation in a short period of time, the long-term output stability of the light source is not ideal. Furthermore, Wang Qi and Zhang Bo analyzed the causes of LED light decay and, based on this research, designed a SEPIC-based LED driver circuit. This circuit can provide an appropriate operating voltage and drive current based on the light decay caused by changes in the lamp's operating temperature, thereby achieving adaptive light decay compensation. However, the circuit design of this topology is relatively complex, requiring a large number of components, which increases the cost of the LED driver design.

[0007] Addressing the widespread issue of colorimetric consistency in LED displays, Chen Yutao analyzed the causes of this problem from the perspectives of LED characteristics, the principles of full-color display, and the characteristics of constant-current drive. He then analyzed the feasibility of implementing point-by-point correction by modifying the pixel color space using the principle of three-primary-color mixing, providing a theoretical basis for implementing colorimetric correction in control systems. Due to the current characteristics of LED lamps, when the current is constant, the LED reaches maximum brightness at full pulse-width modulation (PWM) value. Increasing the PWM value cannot increase the average LED current. The overall concept of correction is to obtain new point-by-point PWM values ​​through color mixing to approximate the average LED current. These new PWM values ​​are somewhat lower than the original values, resulting in a decrease in brightness under normal operating conditions. Furthermore, Chen Yutao, considering the application requirements of high-density displays, determined the basic architecture of a FPGA-based control system. Technical issues

[0008] Although LED display technology in existing technologies has been widely used in many fields, it still faces some technical challenges and problems, including:

[0009] 1) High cost and workload of point-by-point correction:

[0010] Large LED display panels are composed of a large number of tiny pixels, each of which needs to be independently calibrated to achieve the required brightness.

[0011] If point-by-point correction is performed, a huge amount of data processing will be generated, requiring high-performance processors and algorithms.

[0012] In addition, point-by-point calibration is also very costly, involving sophisticated calibration equipment and a time-consuming operation process.

[0013] 2) White balance offset:

[0014] On an LED display panel, white balance is achieved by adjusting the brightness and chromaticity of the red, green, and blue LED sub-pixels.

[0015] Due to various reasons (such as temperature changes, material aging, etc.), the luminous efficiency of each color LED will change, which will cause the white balance to shift and thus affect the display effect. Technical Solutions

[0016] In view of the problems existing in the prior art, the present invention provides a method and system for white balance compensation of an LED display panel.

[0017] The present invention is implemented as follows: the LED display panel white balance compensation method comprises the following steps:

[0018] Step 1: Use FPGA chip to drive M rows and N columns of LED full-color display panel, crystal oscillator frequency F co ;

[0019] Step 2: The crystal oscillator is divided by the FPGA chip W to obtain three synchronous clocks T clk = , respectively control the red LED display driving subsystem, green LED display driving subsystem and blue LED display driving subsystem, the red, green and blue LED sub-pixels are at the ambient temperature t temp When , the relative brightness coefficients are represented by α, β and γ respectively;

[0020] Step 3: The MCU obtains the current ambient temperature t from the temperature sensor temp , the temperature information is transmitted to the FPGA chip, which adjusts the column gating time for the first time according to the ambient temperature and the relative brightness of each primary color LED under different temperature conditions;

[0021] Step 4: The MCU adjusts the period T every column strobe time. run Get the ambient temperature t temp The temperature information is passed to the FPGA chip, and the FPGA chip adjusts the period T every column strobe time. run The column gating time is adjusted once according to the current ambient temperature and the relative brightness coefficients of each primary color LED under different temperature conditions.

[0022] Furthermore, in step 1, each color pixel includes one red, green, and blue sub-pixel, and the entire driving system is divided into a general driving subsystem, a red LED display driving subsystem, a green LED display driving subsystem, and a blue LED display driving subsystem; the red LED display driving subsystem, the green LED display driving subsystem, and the blue LED display driving subsystem meet the requirements that the relative brightness coefficient α=β=γ=1 and the relative brightness ratio αL of the red, green, and blue sub-pixels in each pixel are normally lit in a 25°C environment (without PWM modulation) r25 :βL g25 :γL b25 =1.0000:4.5907:0.0601; the relative brightness coefficients α, β, and γ of the red, green, and blue sub-pixels of a specific material are often different when normally lit in a non-25°C environment (without PWM modulation), and the relationship between temperature and relative brightness coefficient can be obtained through experiments.

[0023] Furthermore, the scanning time of each line of the red, green and blue driving subsystems is equal, and each contains B T clk .

[0024] Furthermore, the frame period is T=M B T clk , , the selected parameters need to satisfy f r =f g =f b >50Hz.

[0025] Further, use ave(j) 25_r 、ave(j) 25_g and ave(j) 25_b (j=1, 2, 3, …, N) represent the average brightness of the luminous pixels in the jth column of the red LED display driver subsystem, the green LED display driver subsystem, and the blue LED display driver subsystem when normally lit (without PWM modulation) in a 25°C environment.

[0026] Further, use ave(j) temp_r 、ave(j) temp_g and ave(j) temp_b(j=1,2,3,…,N) respectively represent the temperature t temp The average brightness of the pixels in the jth column of the red LED display drive subsystem, the green LED display drive subsystem, and the blue LED display drive subsystem when the environment is normally lit (no PWM modulation), and ave(j) temp_r =α ave(j) 25_r 、ave(j) temp_g =β ave(j) 25_g and ave(j) temp_b =γ ave(j) 25_b .

[0027] Furthermore, avemin_temp_r, avemin_temp_g and avemin_temp_b are used to represent the temp The minimum value of the average brightness of the luminous pixels in all columns of the red LED drive subsystem, green LED drive subsystem and blue LED drive subsystem when the environment is normally lit (no PWM modulation), is expressed as ave min_temp Indicates the minimum value of avemin_temp_r, avemin_temp_g, and avemin_temp_b.

[0028] Furthermore, the red LED display driving subsystem, the green LED display driving subsystem and the blue LED display driving subsystem are at a temperature t temp The strobe time of column j in the environment is represented by t(j)column_temp_r, t(j)column_temp_g and t(j)column_temp_b (j=1,2,3,…,N), respectively, and ), ), ), (j=1,2,3,…,N), then the display panel is at temperature t temp Adjust to white balance when using the environment.

[0029] Another object of the present invention is to provide an LED display panel white balance compensation system and a LED display panel white balance compensation method, the system comprising:

[0030] General drive subsystem, including crystal oscillator, temperature module, frequency division module, and timer module;

[0031] Temperature module, the microcontroller obtains the ambient temperature from the temperature sensor regularly according to the requirements of the FPGA chip;

[0032] Frequency division module: the crystal oscillator is divided by the FPGA chip to obtain three synchronous clocks to control the red LED display drive subsystem, green LED display drive subsystem and blue LED display drive subsystem respectively;

[0033] The timer module is used to record the total working time of the display after it is powered on;

[0034] The red LED display driving subsystem includes a red LED display hardware module, a red LED display row scanning module, and a red LED display column strobe module;

[0035] Red LED display hardware module, including hardware devices such as row driver chips and column driver chips suitable for red LED display;

[0036] Red LED display line scanning module, used for progressive scanning of red LED display;

[0037] The red LED display column strobe module is used to dynamically adjust the strobe time of each column of the red LED display.

[0038] Green LED display drive subsystem, including green LED display hardware module, green LED display row scanning module, green LED display column strobe module;

[0039] Green LED display hardware module, including hardware devices such as row driver chips and column driver chips suitable for green LED display;

[0040] Green LED display line scanning module, used for progressive scanning of green LED display;

[0041] Green LED display column strobe module is used to dynamically adjust the strobe time of each column of green LED display.

[0042] The blue LED display driver subsystem includes a blue LED display hardware module, a blue LED display row scanning module, and a blue LED display column strobe module;

[0043] Blue LED display hardware module, including hardware devices such as row driver chips and column driver chips suitable for blue LED display;

[0044] Blue LED display line scanning module, used for line-by-line scanning of blue LED display;

[0045] The blue LED display column strobe module is used to dynamically adjust the strobe time of each column of the blue LED display. Beneficial effects

[0046] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0047] First, the present invention adopts a row-by-row scanning technology based on dynamic adjustment of column selection time to first achieve uniform brightness of the red, green, and blue sub-pixels themselves. Then, combined with the relationship between the relative brightness coefficients of red, green, and blue and temperature, a pulse width modulation (PWM) method is used in the column selection scheme to control the brightness of the red, green, and blue sub-pixels in each pixel to achieve white balance of the red, green, and blue colors.

[0048] Second, the present invention only needs to calibrate column by column, and the number of corrections is the number of columns, which is much less than the number of rows × the number of columns of point-by-point calibration, resulting in lower costs and less workload.

[0049] Based on the different relationships between the relative brightness coefficients of red, green, and blue LEDs made of different materials and ambient temperature, and the characteristic that the relative brightness coefficients α = β = γ = 1 when normally lit in a 25°C environment (without PWM modulation), the present invention uses a timer to record the operating time of the display panel since powering on. The drive system then compensates the brightness displayed by the red, green, and blue LEDs to restore white balance to the display panel. This invention can maintain good white balance even when the ambient temperature changes.

[0050] Third, the expected benefits and commercial value of the technical solution of the present invention after transformation are:

[0051] The LED display panel has a huge number of pixels. Directly performing point-by-point correction based on all pixels of the display panel is costly and labor-intensive. The present invention performs column-by-column correction, and the number of corrections is the number of columns, which is much smaller than the number of rows × the number of columns in point-by-point correction, resulting in lower costs and less workload.

[0052] The present invention solves the white balance problem of LED display panels, so that viewers can watch videos with pure colors, improve user perception, and facilitate product promotion.

[0053] The technical solution of the present invention solves the technical problem of white balance of LED display panels that people have long been eager to solve but have never been able to successfully solve.

[0054] Fourth, the significant technical advancements achieved by the LED display panel white balance compensation system provided by the present invention include:

[0055] 1. Precise control: Because each LED display driver subsystem (red, green, and blue) in the system includes dedicated row scanning and column gating modules, the system can precisely control the lighting time and duration of each sub-pixel, providing more accurate color brightness control and white balance adjustment, thereby improving the quality of the display effect.

[0056] 2. High reliability: Implementing each LED display driver subsystem using FPGA improves system stability and reliability. The FPGA's parallel processing capabilities enable faster system response when adjusting white balance, reducing latency and distortion.

[0057] 3. Flexibility and Programmability: FPGAs offer a high degree of flexibility and programmability, enabling the system to dynamically adjust drive parameters based on different LED display panels, temperature, and other conditions. This flexibility also allows the system to adapt to new display technologies and standards through software updates, protecting investments and extending product lifespan.

[0058] 4. Overall performance improvement: Automatically compensate for brightness when the ambient temperature changes, improving display quality.

[0059] The design of the FPGA-based system provided by the present invention takes into account various situations encountered during the use of LED display panels, and provides an efficient, reliable and long-term maintainable solution through high customization and flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0061] FIG1 is a flow chart of a white balance compensation method for an LED display panel provided by an embodiment of the present invention;

[0062] FIG2 is a structural diagram of a white balance compensation system for an LED display panel provided by an embodiment of the present invention;

[0063] FIG3 is a flow chart of a white balance compensation method for an LED display panel provided by the present invention;

[0064] FIG4 shows the relative brightness coefficient of the LED die at different ambient temperatures using the selected materials according to an embodiment of the present invention. Modes for Carrying Out the Invention

[0065] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0066] In view of the problems existing in the prior art, the present invention provides a method and system for white balance compensation of an LED display panel.

[0067] As shown in FIG1 , an embodiment of the present invention provides a method for compensating white balance of an LED display panel. The method comprises the following steps:

[0068] Step 1: Use FPGA chip to drive LED full-color display panel with M=512 rows and N=1024 columns, and the crystal oscillator frequency F co =20MHz;

[0069] Step 2: The crystal oscillator is divided by FPGA chip W=2 to obtain three synchronous clocks T clk = , respectively control the red LED display driving subsystem, green LED display driving subsystem and blue LED display driving subsystem, the red, green and blue LED sub-pixels are at the ambient temperature t temp When , the relative brightness coefficients are represented by α, β and γ respectively;

[0070] Step 3: The MCU obtains the current ambient temperature t from the temperature sensor temp , the temperature information is transmitted to the FPGA chip, which adjusts the column gating time for the first time according to the ambient temperature and the relative brightness of each primary color LED under different temperature conditions;

[0071] Step 4: The MCU adjusts the period T every column strobe time. run =1h to obtain the ambient temperature t temp The temperature information is passed to the FPGA chip, and the FPGA chip adjusts the period T every column strobe time. run =1h Adjust the column strobe time according to the current ambient temperature and the relative brightness of each primary color LED under different temperature conditions.

[0072] Furthermore, in step 1, each color pixel includes one red, green, and blue sub-pixel, and the entire driving system is divided into a general driving subsystem, a red LED display driving subsystem, a green LED display driving subsystem, and a blue LED display driving subsystem; the red LED display driving subsystem, the green LED display driving subsystem, and the blue LED display driving subsystem meet the requirements that the relative brightness coefficient α=β=γ=1 and the relative brightness ratio αL of the red, green, and blue sub-pixels in each pixel are normally lit in a 25°C environment (without PWM modulation) r25 :βL g25 :γL b25 =1.0000:4.5907:0.0601, so that each color pixel can match the white light of equal energy; the relative brightness coefficients α, β, and γ of the red, green, and blue sub-pixels of a specific material are often different when normally lit in a non-25°C environment (without PWM modulation), and the relationship between temperature and relative brightness coefficient can be obtained through experiments.

[0073] Furthermore, according to the data in FIG4 , the relative brightness coefficients α, β, and γ of the LED material selected in the embodiment are determined as follows:

[0074] t temp ≤ At -15℃, α is α -30 =1.34, β is β -30 =1.03 and γ take γ -30 =1.01;

[0075] -15℃ <t temp ≤ At 12.5℃, α takes α0=1.155, β takes β0=1.02 and γ takes γ0=1.005;

[0076] 12.5℃ <t temp ≤ At 42.5℃, α is α 25 =1, β is taken as β 25 =1 and γ takes γ 25 =1;

[0077] 42.5℃ <t temp ≤ At 70℃, α is α 60 =0.99, β is taken as β 60 =0.94 and γ takes γ 60 =0.765;

[0078] 70℃ <t temp When α is α 60 =0.98, β is taken as β 60 =0.905 and γ takes γ 60 =0.63.

[0079] Furthermore, the scanning time of each line of the red, green and blue driving subsystems is equal, and each contains B=256 T clk .

[0080] Furthermore, the frame period is T=M B T clk , , the selected parameters need to satisfy f r =f g =f b 76Hz>50Hz.

[0081] Further, use ave(j)25_r 、ave(j) 25_g and ave(j) 25_b (j=1, 2, 3, …, N) represent the average brightness of the luminous pixels in the jth column of the red LED display driver subsystem, the green LED display driver subsystem, and the blue LED display driver subsystem when normally lit (without PWM modulation) in a 25°C environment.

[0082] Further, use ave(j) temp_r 、ave(j) temp_g and ave(j) temp_b (j=1,2,3,…,N) respectively represent the temperature t temp The average brightness of the pixels in the jth column of the red LED display drive subsystem, the green LED display drive subsystem, and the blue LED display drive subsystem when the environment is normally lit (no PWM modulation), and ave(j) temp_r =α ave(j) 25_r 、ave(j) temp_g =β ave(j) 25_g and ave(j) temp_b =γ ave(j) 25_b .

[0083] Furthermore, avemin_temp_r, avemin_temp_g and avemin_temp_b are used to represent the temp The minimum value of the average brightness of the luminous pixels in all columns of the red LED drive subsystem, green LED drive subsystem and blue LED drive subsystem when the environment is normally lit (no PWM modulation), is expressed as ave min_temp Indicates the minimum value of avemin_temp_r, avemin_temp_g, and avemin_temp_b.

[0084] Furthermore, the red LED display driving subsystem, the green LED display driving subsystem and the blue LED display driving subsystem are at a temperature t temp The strobe time of column j in the environment is represented by t(j)column_temp_r, t(j)column_temp_g and t(j)column_temp_b (j=1,2,3,…,N), respectively, and ), ), ), (j=1,2,3,…,N), then the display panel is at temperature t temp Adjust to white balance when using the environment.

[0085] As shown in FIG2 , an embodiment of the present invention provides an LED display panel white balance compensation method and an LED display panel white balance compensation system, the system comprising:

[0086] General drive subsystem, including crystal oscillator, temperature module, frequency division module, and timer module;

[0087] Temperature module, the microcontroller obtains the ambient temperature from the temperature sensor regularly according to the requirements of the FPGA chip;

[0088] Frequency division module: the crystal oscillator is divided by the FPGA chip to obtain three synchronous clocks to control the red LED display drive subsystem, green LED display drive subsystem and blue LED display drive subsystem respectively;

[0089] The timer module is used to record the total working time of the display after it is powered on;

[0090] The red LED display driving subsystem includes a red LED display hardware module, a red LED display row scanning module, and a red LED display column strobe module;

[0091] Red LED display hardware module, including hardware devices such as row driver chips and column driver chips suitable for red LED display;

[0092] Red LED display line scanning module, used for progressive scanning of red LED display;

[0093] The red LED display column strobe module is used to dynamically adjust the strobe time of each column of the red LED display.

[0094] Green LED display drive subsystem, including green LED display hardware module, green LED display row scanning module, green LED display column strobe module;

[0095] Green LED display hardware module, including hardware devices such as row driver chips and column driver chips suitable for green LED display;

[0096] Green LED display line scanning module, used for progressive scanning of green LED display;

[0097] Green LED display column strobe module is used to dynamically adjust the strobe time of each column of green LED display.

[0098] The blue LED display driver subsystem includes a blue LED display hardware module, a blue LED display row scanning module, and a blue LED display column strobe module;

[0099] Blue LED display hardware module, including hardware devices such as row driver chips and column driver chips suitable for blue LED display;

[0100] Blue LED display line scanning module, used for line-by-line scanning of blue LED display;

[0101] The blue LED display column strobe module is used to dynamically adjust the strobe time of each column of the blue LED display.

[0102] This technical solution is a white balance compensation system for LED display panels based on a field programmable gate array (FPGA). Its detailed working principle is as follows:

[0103] 1) General drive subsystem: The system first generates a reference clock signal through a crystal oscillator. This clock signal is divided into three synchronized clock signals within the FPGA through a frequency divider module, which are used to control the red, green, and blue LED display drive subsystems respectively. The timer module is used to record the total operating time of the display after power-on. In the temperature module, the microcontroller periodically obtains the ambient temperature from the temperature sensor according to the requirements of the FPGA chip.

[0104] 2) Red, green, and blue LED display driver subsystems: Each color LED display driver subsystem includes a hardware module, a row scan module, and a column selection module.

[0105] The hardware module includes row driver chips and column driver chips, which are the hardware that actually drives the LED display elements to light up.

[0106] The line scanning module is used for line-by-line scanning of red, green and blue LED displays.

[0107] The column strobe module controls the strobe time of each column of pixels so that the correct pixel column can be illuminated when a specific row is selected, and the lighting duration within the column strobe time can be programmed according to the PWM method.

[0108] 3) White Balance Compensation: Because the relative brightness coefficients of different red, green, and blue LED materials vary with temperature, and the magnitude of the change varies, resulting in white balance shift, the system needs to adjust the drive timing of each subpixel to maintain white balance. Based on the relationship between the relative brightness coefficients of the selected red, green, and blue LED materials and temperature, and by regularly acquiring ambient temperature information, the FPGA determines how to adjust the column strobe timing to compensate for white balance shifts caused by temperature changes, thereby maintaining the display panel's image quality.

[0109] 4) Dynamic adjustment: Due to the high flexibility and fast processing capabilities of FPGA, the system can monitor the display status in real time and quickly adjust the parameters of each driver module as needed to respond to different display content and environmental changes to maintain the best display effect.

[0110] The FPGA-based system provided by the embodiment of the present invention effectively achieves timely compensation of the white balance of the LED panel through precise clock management and dynamic adjustment, while providing a stable solution that can adapt to ambient temperature changes and is easy to maintain and upgrade.

[0111] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A white balance compensation method for an LED display panel, characterized in that, including the following steps: Step 1: Drive an M-row and N-column LED full-color display panel with an FPGA chip, and the crystal oscillator frequency is F co ; Step 2: The crystal oscillator is divided by W through the FPGA chip to obtain three synchronous clocks T clk = , respectively control the red LED display driving subsystem, the green LED display driving subsystem, and the blue LED display driving subsystem. The relative luminance coefficients of the red, green, and blue LED sub-pixels are represented by α, β, and γ at the ambient temperature t temp respectively; Step 3: The single-chip microcomputer obtains the current ambient temperature t from the temperature sensor temp , and transfers the temperature information to the FPGA chip. The FPGA chip adjusts the column strobe time once for the first time according to the ambient temperature and the different relative brightnesses of each primary color LED under different temperature conditions; Step 4, the single-chip microcomputer adjusts every column strobe time adjustment period T run to obtain the ambient temperature t temp , and transmits the temperature information to the FPGA chip. The FPGA chip adjusts the column strobe time once every column strobe time adjustment period T run according to the current ambient temperature and the different relative brightnesses of each primary color LED under different temperature conditions.

2. The white balance compensation method for the LED display panel according to claim 1, wherein In Step 1, each color pixel contains one red, green, and blue sub-pixel, and the entire driving system is divided into a general driving subsystem, a red LED display driving subsystem, a green LED display driving subsystem, and a blue LED display driving subsystem; the red LED display driving subsystem, the green LED display driving subsystem, and the blue LED display driving subsystem satisfy that the relative luminance coefficients α = β = γ = 1 when the red, green, and blue sub-pixels within each pixel are normally lit (without PWM modulation) in a 25°C environment, and the relative luminance ratio αL r25 : βL g25 : γL b25 = 1.0000: 4.5907: 0.0601; for the red, green, and blue sub-pixels of a specific material, the relative luminance coefficients α, β, and γ are often different when they are normally lit (without PWM modulation) in a non-25°C environment, and the relationship between temperature and relative luminance coefficients can be obtained through experiments.

3. The white balance compensation method for an LED display panel according to claim 1, wherein The scanning time per row of the three driving subsystems for red, green, and blue is equal, and each contains B Ts clk 。 4. The white balance compensation method for the LED display panel according to claim 1, wherein, The frame period is T = M B T clk , , the selected parameters need to satisfy f r =f g =f b > 50 Hz.

5. The white balance compensation method for the LED display panel according to claim 1, characterized in that Use ave(j) 25_r 、ave(j) 25_g and ave(j) 25_b (j = 1, 2, 3, …, N) respectively represent the average luminous pixel brightness of the j-th column of the red LED display driving subsystem, the green LED display driving subsystem, and the blue LED display driving subsystem when normally lit (without PWM modulation) at an ambient temperature of 25°C.

6. The white balance compensation method for the LED display panel according to claim 1, wherein Use ave(j) temp_r 、ave(j) temp_g and ave(j) temp_b (j = 1, 2, 3, …, N) respectively represent the average luminous pixel brightness of the j-th column of the red LED display driving subsystem, the green LED display driving subsystem, and the blue LED display driving subsystem when the environment is normally lit (without PWM modulation) at temperature t temp , and ave(j) temp_r = α ave(j) 25_r 、ave(j) temp_g = β ave(j) 25_g and ave(j) temp_b = γ ave(j) 25_b .

7. The white balance compensation method for an LED display panel according to claim 1, wherein, Let avemin_temp_r, avemin_temp_g, and avemin_temp_b respectively represent the minimum value of the average brightness of the light-emitting pixels in all columns of the red LED driving subsystem, green LED driving subsystem, and blue LED driving subsystem when the ambient is normally lit (without PWM modulation) at temperature t temp Let ave represent the minimum value of avemin_temp_r, avemin_temp_g, and avemin_temp_b when the ambient is normally lit (without PWM modulation) at temperature t min_temp represent the minimum value of avemin_temp_r, avemin_temp_g, and avemin_temp_b 8. The white balance compensation method for the LED display panel according to claim 1, wherein The gating times of the red LED display driving subsystem, the green LED display driving subsystem, and the blue LED display driving subsystem for the j-th column at temperature t temp are represented by t(j)column_temp_r, t(j)column_temp_g, and t(j)column_temp_b (j = 1, 2, 3, …, N) respectively when in the environment, and ), ), (j = 1, 2, 3, …, N). Then the display panel is adjusted to white balance at temperature t temp in the environment.

9. An LED display panel white balance compensation system for the LED display panel white balance compensation method according to any one of claims 1 to 8, characterized in that, The system includes: A general driving subsystem, including a crystal oscillator, a temperature module, a frequency division module, and a timer module; A temperature module, where the single-chip microcomputer regularly obtains the ambient temperature from the temperature sensor according to the requirements of the FPGA chip; A frequency division module, where the crystal oscillator is frequency-divided by the FPGA chip to obtain three synchronous clocks to respectively control the red LED display driving subsystem, the green LED display driving subsystem, and the blue LED display driving subsystem; A timer module, used to record the total working duration of the display after this power-on; A red LED display driving subsystem, including a red LED display hardware module, a red LED display line scanning module, and a red LED display column strobe module; A red LED display hardware module, including hardware devices such as a row driving chip and a column driving chip suitable for red LED display; A red LED display line scanning module, used for progressive scanning of the red LED display; A red LED display column strobe module, used to dynamically adjust the strobe time of each column of the red LED display. A green LED display driving subsystem, including a green LED display hardware module, a green LED display line scanning module, and a green LED display column strobe module; A green LED display hardware module, including hardware devices such as a row driving chip and a column driving chip suitable for green LED display; A green LED display line scanning module, used for progressive scanning of the green LED display; A green LED display column strobe module, used to dynamically adjust the strobe time of each column of the green LED display. A blue LED display driving subsystem, including a blue LED display hardware module, a blue LED display line scanning module, and a blue LED display column strobe module; A blue LED display hardware module, including hardware devices such as a row driving chip and a column driving chip suitable for blue LED display; A blue LED display line scanning module, used for progressive scanning of the blue LED display; A blue LED display column strobe module, used to dynamically adjust the strobe time of each column of the blue LED display.

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