Liquid crystal display system with color compensation function

Abstract

The utility model provides a kind of liquid crystal display system with color compensation function, including system power supply circuit, single-chip microcomputer circuit, constant-current source circuit, LED crystal circuit and color compensation circuit.Single-chip microcomputer circuit is connected with constant-current source circuit, the output end of constant-current source circuit is connected with LED crystal circuit, and single-chip microcomputer circuit will control the PWM signal of four color crystal, respectively corresponding to be sent to the constant-current source circuit of four color crystal, drive corresponding crystal in LED crystal circuit to emit light;Single-chip microcomputer circuit is also connected with color compensation circuit, and color compensation circuit is connected with constant-current source circuit, and single-chip microcomputer circuit controls the MOS pipe in the color compensation circuit of four color crystal according to day / night mode, and then the color compensation circuit of four color crystal adjusts the resistance value of FB feedback resistance corresponding to its constant-current source circuit, to adjust the output current size of each constant-current source circuit, so as to adjust the light emitting state of each color crystal in LED crystal circuit.

Description

Technical Field

[0001] This utility model belongs to the field of display system technology, and specifically relates to a liquid crystal display system with color compensation function. Background Technology

[0002] An excellent LCD screen should possess numerous optical technical specifications, such as brightness, contrast ratio, color coordinates, and color temperature. Brightness and contrast ratio are fundamental specifications that determine whether users can clearly see the information displayed. Color coordinates and color temperature, on the other hand, are higher-level specifications that affect whether users experience glare, eye strain, or difficulty seeing the screen in different or specific environments. In the aviation display sector, and considering the recent development needs of various display industries, customers are increasingly focusing on the color coordinates and color temperature of LCD screens to ensure pilot comfort and safety.

[0003] The optical module of an LCD screen, besides the LED backlight board, also includes many other optical components such as light guide plates, multi-layer optical films, and filter glass. However, the fundamental factor affecting the optical performance of an LCD screen lies in the LED chips (commonly known as LED beads, hereinafter referred to as chips) on the LED backlight board. For example, the luminous flux of the chip at a specific current mainly determines the brightness of the LCD screen; and the wavelength of the chip mainly determines the color coordinates / color temperature of the LCD screen.

[0004] Even within the same batch of wafers produced by wafer foundries, performance indicators cannot be guaranteed to be completely consistent and will fluctuate within a certain range, even if they are considered to be the same model of wafer. However, when the wavelength of light emitted by different LED panels of the same model of wafer differs by nearly 3nm, the colors displayed after passing through the optical film and LCD screen will have differences that are visible to the naked eye. If a professional luminance meter is used to test the color coordinates and color temperature indicators at this time, there will be obvious differences in the indicators of the two LED panels.

[0005] To adjust color differences between different LCD screens, it's necessary to try and make the color coordinates or color temperature of the two screens as consistent as possible. Currently, many LCD screen products don't employ special measures; they simply rely on strict control over the wafers to reduce color differences between batches. This method has significant drawbacks. When color differences occur between different batches of LCD screens, the wafer manufacturer has to remanufacture the wafers and re-install the backlight panels to resolve the issue. Whether the wafer manufacturer can succeed on the first try is another matter, but this solution significantly increases material and time costs. Utility Model Content

[0006] This invention addresses the shortcomings of existing technologies by providing a liquid crystal display system with color compensation functionality. This design offers excellent portability and can meet the needs of products with different display systems, screen sizes, and application scenarios.

[0007] This utility model is achieved through the following technical solution: A liquid crystal display system with color compensation function includes: a system power supply circuit, a microcontroller circuit, a constant current source circuit, an LED chip circuit, and a color compensation circuit. The system power supply circuit is connected to the microcontroller circuit and the constant current source circuit to provide them with operating voltage. The microcontroller circuit is connected to the constant current source circuit, and the output terminal of the constant current source circuit is connected to the LED chip circuit. The microcontroller circuit is also connected to the color compensation circuit, and the color compensation circuit is connected to the constant current source circuit.

[0008] In the above technical solution, the system power supply circuit includes three DC-DC power chips: the first power chip is connected to the microcontroller circuit, the second power chip is connected to the constant current source circuit of the white chip, and the third power chip is connected to the constant current source circuit of the blue, orange and green chips.

[0009] In the above technical solution, the microcontroller circuit adopts the GD32F103 microcontroller.

[0010] In the above technical solution, the microcontroller circuit includes at least: one TTL communication serial port, one I / O interface for controlling day and night mode, and four I / O interfaces for outputting PWM signals; wherein, the microcontroller's TTL communication serial port is connected to the host computer; the microcontroller's I / O interface for controlling day and night mode is connected to the color compensation circuit; and the microcontroller's four I / O interfaces for outputting PWM signals are respectively connected to the constant current source circuits of the four-color chip.

[0011] In the above technical solution, the constant current source circuit has four channels: a constant current source circuit for the white chip, a constant current source circuit for the blue chip, a constant current source circuit for the orange chip, and a constant current source circuit for the green chip.

[0012] In the above technical solution, each constant current source circuit uses the domestically produced SGM3749 constant current source chip.

[0013] In the above technical solution, the color compensation circuit comprises four channels: a color compensation circuit for the white chip, a color compensation circuit for the blue chip, a color compensation circuit for the orange chip, and a color compensation circuit for the green chip. Each color compensation circuit uses a MOSFET with FB feedback resistors connected to the source and drain of the MOSFET. The gate of the MOSFET in each color compensation circuit is connected to a microcontroller circuit. The FB feedback resistor of the white chip color compensation circuit is connected to the FB feedback terminal of the constant current source circuit of the white chip, the FB feedback resistor of the blue chip color compensation circuit is connected to the FB feedback terminal of the constant current source circuit of the blue chip, the FB feedback resistor of the orange chip color compensation circuit is connected to the FB feedback terminal of the constant current source circuit of the orange chip, and the FB feedback resistor of the green chip color compensation circuit is connected to the FB feedback terminal of the constant current source circuit of the green chip.

[0014] In the above technical solution, the LED chip circuit has four channels: a white chip circuit, a blue chip circuit, an orange chip circuit, and a green chip circuit. The white chip circuit is connected to the output terminal of the constant current source circuit of the white chip, the blue chip circuit is connected to the output terminal of the constant current source circuit of the blue chip, the orange chip circuit is connected to the output terminal of the constant current source circuit of the orange chip, and the green chip circuit is connected to the output terminal of the constant current source circuit of the green chip.

[0015] The advantages and beneficial effects of this utility model are as follows: Compared with existing technologies, this invention features simple circuitry, convenient debugging, high precision, strong stability, strong portability, and significant savings in economic and time costs. This invention uses a microcontroller as the main control chip. When the host computer provides a daytime mode, the LCD screen needs to operate in a high-brightness white light mode. In this case, the microcontroller connects to the color compensation circuit, allowing the user to adjust the color coordinates and color temperature of the LCD screen by increasing the proportion of blue / orange / green pixels in the high-brightness white light mode. When the host computer provides a nighttime mode, the LCD screen needs to operate in a low-brightness mode. In this case, depending on whether the customer has night vision compatibility requirements, the system can choose between a white light-dominant, three-color light compensation mode, or a three-color light mixing mode. The microcontroller used in this system allows for easy software modification and upgrades and has strong environmental adaptability. This system is low-cost, high-precision, stable, and has strong anti-interference capabilities. This invention can be applied to LCD screens of different sizes and in different environments across various fields. Attached Figure Description

[0016] Figure 1 This is a structural block diagram of the liquid crystal display system with color compensation function according to this utility model.

[0017] Figure 2 This is a schematic diagram of the system power supply circuit.

[0018] Figure 3 This is a schematic diagram of a microcontroller circuit.

[0019] Figure 4 This is a schematic diagram of a constant current source circuit.

[0020] Figure 5 This is a schematic diagram of a color compensation circuit.

[0021] Figure 6 This is a schematic diagram of an LED chip circuit. Detailed Implementation

[0022] The technical solution of this utility model will be further illustrated below with specific examples.

[0023] like Figure 1 As shown, a liquid crystal display system with color compensation function includes: a system power supply circuit, a microcontroller circuit, a constant current source circuit, an LED chip circuit, and a color compensation circuit. The system power supply circuit is connected to the microcontroller circuit and the constant current source circuit, providing them with operating voltage. The microcontroller circuit is connected to the constant current source circuit, and the output of the constant current source circuit is connected to the LED chip circuit. The microcontroller circuit sends the PWM signals controlling the four color chips to the corresponding constant current source circuits of the four color chips through its I / O interface. The constant current source circuits of the four color chips then drive the corresponding LED chips in the LED chip circuit according to their PWM signal states. The LED emits light; the microcontroller circuit is also connected to the color compensation circuit, which is connected to the constant current source circuit. The microcontroller circuit can communicate with the host computer to obtain the day / night mode information provided by the host computer. According to the day / night mode, the microcontroller circuit sends high / low level signals to the color compensation circuit of the four-color LED, controlling the MOSFET in the color compensation circuit of the four-color LED to be in the on / off state. Then, the color compensation circuit of the four-color LED adjusts the resistance value of the FB feedback resistor of its corresponding constant current source circuit to adjust the output current of each constant current source circuit, thereby adjusting the light emission state of each color LED in the LED chip circuit.

[0024] In other words, the methods for adjusting the color of LED chips are as follows: First, by adjusting the resistance value of the FB feedback resistor of each constant current source, the rated output current of each constant current source circuit is controlled; second, by adjusting the state of the PWM signal output by the microcontroller (period, frequency, duty cycle, etc.), the actual output current of each constant current source is precisely controlled, the illumination state of each color chip is controlled, and thus the display color, color temperature / color coordinates, and other indicators of the LCD screen are controlled.

[0025] The circuit structure of each circuit unit will be described in detail below with reference to the attached diagram.

[0026] like Figure 2 As shown, the system power supply circuit includes three DC-DC power chips: the first power chip powers the microcontroller circuit, with an input voltage of 5V and an output voltage of 3.3V; the second power chip powers the constant current source circuit of the white chip, with an input voltage of 28V and an output voltage of 16V; and the third power chip powers the constant current source circuit of the color chips (blue, orange, and green chips), with an input voltage of 28V and an output voltage of 5V.

[0027] Figure 3 As shown, the microcontroller circuit uses a GD32F103 microcontroller and includes at least: one TTL communication serial port, one I / O interface for controlling day / night mode, and four I / O interfaces for outputting PWM signals. The microcontroller's TTL communication serial port is connected to the host computer to obtain communication information such as the day / night mode given by the host computer. The microcontroller's I / O interface for controlling day / night mode is used to set the current mode to a high / low state and output it to the color compensation circuit, causing the MOS transistor of the color compensation circuit to be in an on / off state. The microcontroller's four I / O interfaces for outputting PWM signals are connected one-to-one with the constant current source circuits of the four-color LEDs. The frequency, period, duty cycle, and other states of each PWM signal can be configured according to user needs, and the PWM signals controlling the four-color LEDs are sent to the corresponding constant current source circuits of the four-color LEDs to complete the adjustment and control functions of the screen display colors.

[0028] Figure 4 As shown, the constant current source circuit has four channels: one for the white LED, one for the blue LED, one for the orange LED, and one for the green LED. Each constant current source circuit uses the domestically produced SGM3749 constant current source chip. The operating parameters of this chip are: input voltage 3V-20V, maximum output voltage up to 38V, and FB voltage 200mV. During design, the input voltage of the constant current source circuit needs to be set according to the characteristics and arrangement of the LED chips. Preferably, the input voltage of the constant current source circuit for the white LED is 16V, and the input voltage of the constant current source circuits for the other colored LEDs (blue, orange, and green) is 5V.

[0029] Figure 5As shown, the color compensation circuit has four channels: a color compensation circuit for the white chip, a color compensation circuit for the blue chip, a color compensation circuit for the orange chip, and a color compensation circuit for the green chip. Each color compensation circuit uses a MOSFET with FB feedback resistors connected to the source and drain of the MOSFET. The gate of the MOSFET in each color compensation circuit is connected to a microcontroller, which controls the switching of the MOSFET according to the day / night mode signal. The FB feedback resistor of the white chip's color compensation circuit is connected to the FB feedback terminal (i.e., the FB pin) of the constant current source circuit of the white chip. The FB feedback resistor of the color compensation circuit for the blue chip is connected to the FB feedback terminal of the constant current source circuit for the blue chip; the FB feedback resistor of the color compensation circuit for the orange chip is connected to the FB feedback terminal of the constant current source circuit for the orange chip; and the FB feedback resistor of the color compensation circuit for the green chip is connected to the FB feedback terminal of the constant current source circuit for the green chip. By controlling the switching state of the MOSFETs through a microcontroller and by pre-configuring the resistance value of the FB feedback resistor in each color compensation circuit, the output current of each corresponding constant current source circuit can be adjusted, ultimately adjusting the lighting state of each color chip circuit in the LED chip circuit.

[0030] Preferably, the backlight is mainly white light, which has a higher operating current, while other colored lights are used as compensation light sources, with relatively lower operating current. Therefore, when the backlight mode is daytime mode, the microcontroller controls the MOSFET to turn on. The FB feedback resistor of the color compensation circuit of the white chip is 0.62Ω in parallel with 30Ω. According to the constant current source chip datasheet, the output current of the constant current source circuit of the white chip can be calculated to be approximately 325mA. The FB feedback resistor of the color compensation circuit of the blue chip is 5.6Ω in parallel with 130Ω. According to the constant current source chip datasheet, the output current of the constant current source circuit of the blue chip can be calculated to be approximately 37mA. Similarly, the FB feedback resistors of the color compensation circuits of other colored chips are configured to adjust the output current of the constant current source circuits of the corresponding colored chips.

[0031] Figure 6As shown, the LED chip circuit has four channels: a white chip circuit, a blue chip circuit, an orange chip circuit, and a green chip circuit. The white chip circuit is connected to the output terminal of the constant current source circuit of the white chip, the blue chip circuit is connected to the output terminal of the constant current source circuit of the blue chip, the orange chip circuit is connected to the output terminal of the constant current source circuit of the orange chip, and the green chip circuit is connected to the output terminal of the constant current source circuit of the green chip. Each channel uses a combination of multiple chips in series and parallel. The suitable chip distribution is calculated based on factors such as the actual size of the project and the module status. The main parameters of the white chip circuit are: operating voltage of approximately 2.4V-2.8V, operating current not exceeding 200mA, and a 5-parallel 9-series distribution (i.e., a total of 5 strings of white chips are connected in parallel, and each string of white chips consists of...). The main parameters of the blue chip circuit are: operating voltage approximately 2.4V-2.9V, operating current not exceeding 50mA, and a 2-parallel-7-series distribution (i.e., two strings of blue chips are connected in parallel, and each string of blue chips consists of seven blue chips connected in series); the main parameters of the orange chip circuit are: operating voltage approximately 2.4V-2.9V, operating current not exceeding 50mA, and a 2-parallel-7-series distribution (i.e., two strings of orange chips are connected in parallel, and each string of orange chips consists of seven orange chips connected in series); the main parameters of the green chip circuit are: operating voltage approximately 2.4V-2.9V, operating current not exceeding 50mA, and a 2-parallel-7-series distribution (i.e., two strings of green chips are connected in parallel, and each string of green chips consists of seven green chips connected in series).

[0032] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A liquid crystal display system with color compensation function, characterized in that: It includes a system power supply circuit, a microcontroller circuit, a constant current source circuit, an LED chip circuit, and a color compensation circuit. The system power supply circuit is connected to the microcontroller circuit and the constant current source circuit to provide them with operating voltage. The microcontroller circuit is connected to the constant current source circuit, and the output terminal of the constant current source circuit is connected to the LED chip circuit. The microcontroller circuit is also connected to the color compensation circuit, and the color compensation circuit is connected to the constant current source circuit.

2. The liquid crystal display system with color compensation function according to claim 1, characterized in that: The system power supply circuit includes three DC-DC power chips: the first power chip is connected to the microcontroller circuit, the second power chip is connected to the constant current source circuit of the white chip, and the third power chip is connected to the constant current source circuit of the blue, orange, and green chips.

3. The liquid crystal display system with color compensation function according to claim 1, characterized in that: The microcontroller circuit uses a GD32F103 microcontroller.

4. The liquid crystal display system with color compensation function according to claim 1, characterized in that: The microcontroller circuit includes at least: one TTL communication serial port, one I / O interface for controlling day / night mode, and four I / O interfaces for outputting PWM signals; wherein, the microcontroller's TTL communication serial port is connected to the host computer; the microcontroller's I / O interface for controlling day / night mode is connected to the color compensation circuit; and the microcontroller's four I / O interfaces for outputting PWM signals are respectively connected to the constant current source circuits of the four-color chip.

5. The liquid crystal display system with color compensation function according to claim 1, characterized in that: The constant current source circuit has four channels: a constant current source circuit for the white chip, a constant current source circuit for the blue chip, a constant current source circuit for the orange chip, and a constant current source circuit for the green chip.

6. The liquid crystal display system with color compensation function according to claim 5, characterized in that: Each constant current source circuit uses the domestically produced SGM3749 constant current source chip.

7. The liquid crystal display system with color compensation function according to claim 5, characterized in that: The color compensation circuit consists of four channels: a color compensation circuit for the white chip, a color compensation circuit for the blue chip, a color compensation circuit for the orange chip, and a color compensation circuit for the green chip. Each color compensation circuit uses a MOSFET with FB feedback resistors connected to the source and drain of the MOSFET. The gate of the MOSFET in each color compensation circuit is connected to the microcontroller circuit. The FB feedback resistor of the white chip color compensation circuit is connected to the FB feedback terminal of the constant current source circuit of the white chip, the FB feedback resistor of the blue chip color compensation circuit is connected to the FB feedback terminal of the constant current source circuit of the blue chip, the FB feedback resistor of the orange chip color compensation circuit is connected to the FB feedback terminal of the constant current source circuit of the orange chip, and the FB feedback resistor of the green chip color compensation circuit is connected to the FB feedback terminal of the constant current source circuit of the green chip.

8. The liquid crystal display system with color compensation function according to claim 5, characterized in that: The LED chip circuit has four channels: a white chip circuit, a blue chip circuit, an orange chip circuit, and a green chip circuit. The white chip circuit is connected to the output terminal of the constant current source circuit of the white chip, the blue chip circuit is connected to the output terminal of the constant current source circuit of the blue chip, the orange chip circuit is connected to the output terminal of the constant current source circuit of the orange chip, and the green chip circuit is connected to the output terminal of the constant current source circuit of the green chip.

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