A control method of a liquid crystal display

Abstract

The application discloses a control method of a liquid crystal display. The method comprises the following steps: acquiring image data to be displayed and generating an initial gray scale voltage set; detecting a current working temperature of a liquid crystal display panel in real time, and generating a corresponding gray scale voltage compensation coefficient set according to a preset temperature-compensation coefficient mapping table; performing gray scale-by-gray scale superposition operation on the initial gray scale voltage set and the gray scale voltage compensation coefficient set to generate a target gray scale voltage set; and driving the liquid crystal display panel to display images according to the target gray scale voltage set. Through real-time temperature detection and dynamic voltage compensation, the application effectively solves problems such as display brightness drift, color deviation and response speed change of the liquid crystal display caused by temperature change. Through multi-point temperature detection and independent compensation in different zones, the application solves the problem of display uniformity caused by local temperature unevenness of the panel; and through introduction of cumulative use time length for aging compensation, the application prolongs the effective service life of the product.

Description

Technical Field

[0001] This invention relates to the field of display technology, specifically to a control method for a liquid crystal display. Background Technology

[0002] Liquid crystal displays (LCDs) are widely used in electronic devices such as televisions, computer monitors, and mobile terminals due to their advantages of small size, light weight, and low power consumption. The display principle of LCDs utilizes the optical anisotropy of liquid crystal molecules. By applying different voltages to change the deflection angle of the liquid crystal molecules, the transmittance of light emitted by the backlight module is controlled, thus achieving the display of different gray levels.

[0003] However, the optical properties of liquid crystal materials are highly sensitive to temperature. Specifically, parameters such as rotational viscosity, elastic constant, and dielectric anisotropy of liquid crystals change significantly with temperature, causing the deflection response speed and steady-state deflection angle of liquid crystal molecules to drift with temperature under the same driving voltage. In existing technologies, liquid crystal displays typically use a preset gamma curve to correct the grayscale voltage to ensure the linearity of the display brightness. However, such correction is usually performed under room temperature conditions and does not consider the impact of actual operating temperature changes on the liquid crystal response characteristics.

[0004] When an LCD monitor operates at low temperatures, the liquid crystal viscosity increases, the response speed slows down, and dynamic trailing is more likely to occur. Simultaneously, the actual transmittance at the same grayscale voltage is lower than at room temperature, resulting in lower display brightness and reduced contrast. When an LCD monitor operates at high temperatures, the liquid crystal viscosity decreases, the response speed speeds up, but overshoot is more likely to occur. Additionally, dark-state light leakage increases, leading to problems such as decreased contrast and grayscale inversion.

[0005] In addition, the existing technology has the following shortcomings: First, temperature compensation usually adopts an overall compensation method, which cannot solve the problem of display uniformity caused by local heating of the backlight module or uneven distribution of ambient temperature; Second, it does not consider the characteristic drift caused by material aging after long-term use of LCDs; Third, the temperature compensation coefficient is an open-loop control, which lacks a real-time verification and dynamic correction mechanism for the compensation effect, and the compensation accuracy decreases after long-term operation.

[0006] Therefore, how to provide a control method for liquid crystal displays that can adapt to temperature changes and ensure stable display quality is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention discloses a control method for a liquid crystal display, comprising the following steps:

[0008] Step 1: Obtain the image data to be displayed, and generate an initial grayscale voltage set based on the image data to be displayed;

[0009] Step 2: Real-time detection of the current operating temperature of the LCD panel, and generation of a grayscale voltage compensation coefficient set corresponding to the current operating temperature based on a preset temperature-compensation coefficient mapping table;

[0010] Step 3: Perform a gray-level superposition operation on the initial gray-level voltage set and the gray-level voltage compensation coefficient set to generate the target gray-level voltage set;

[0011] Step 4: Drive the liquid crystal display panel to display images according to the target grayscale voltage set.

[0012] As a preferred embodiment of the present invention, the method for real-time detection of the current operating temperature of the liquid crystal display panel in step two specifically includes:

[0013] Step 2.1: Collect temperature values ​​of different areas of the panel by using multiple temperature sensors evenly distributed in the non-display area of ​​the liquid crystal display panel;

[0014] Step 2.2: Calculate the average temperature of the multiple temperature sensors as the current operating temperature.

[0015] As a preferred technical solution of the present invention, the method further includes: when the difference between the temperature value collected by any of the temperature sensors and the average temperature exceeds a preset threshold, it is determined that the panel has a local temperature abnormality. In step three, a local target grayscale voltage set is independently generated for the display area corresponding to the temperature sensor, so as to perform independent voltage compensation driving on the display area.

[0016] As a preferred technical solution of the present invention, the preset temperature-compensation coefficient mapping table is established in advance by measuring the deviation curve between the actual transmittance and the target transmittance of the liquid crystal display panel at different ambient temperatures, and calculating the compensation coefficient of each gray level at different temperatures through a reverse interpolation algorithm based on the deviation curve, and then storing it in the non-volatile memory of the liquid crystal display.

[0017] As a preferred embodiment of the present invention, before the gray-level superposition operation in step three, the method further includes: obtaining the cumulative usage time of the liquid crystal display panel; obtaining an aging compensation coefficient from a preset aging compensation table based on the cumulative usage time; and performing a joint superposition operation on the aging compensation coefficient, the initial gray-level voltage set, and the gray-level voltage compensation coefficient set to generate the target gray-level voltage set.

[0018] As a preferred technical solution of the present invention, the method further includes: after step four, acquiring the actual display brightness of the liquid crystal display panel in real time; comparing the actual display brightness with the theoretical display brightness calculated based on the target grayscale voltage set, and calculating the closed-loop error; dynamically correcting the grayscale voltage compensation coefficient set according to the closed-loop error, and feeding back the corrected coefficients to update the preset temperature-compensation coefficient mapping table.

[0019] As a preferred embodiment of the present invention, the initial grayscale voltage set, the grayscale voltage compensation coefficient set, and the target grayscale voltage set are all voltage vector sets containing independent data channels of red sub-pixels, green sub-pixels, and blue sub-pixels.

[0020] The beneficial effects of this invention are as follows: This invention detects the operating temperature of the liquid crystal display panel in real time and generates corresponding grayscale voltage compensation coefficients according to a preset temperature-compensation coefficient mapping table. The compensation coefficients are then superimposed with the initial grayscale voltage to drive the display, effectively solving the problem of liquid crystal response characteristic drift caused by temperature changes and ensuring the stability of display brightness and color under different temperature environments. By uniformly deploying multiple temperature sensors and performing independent voltage compensation driving for local temperature anomalies, the problem of poor display uniformity caused by local temperature unevenness, which cannot be solved by traditional overall temperature compensation, is overcome, significantly improving the display consistency of the display panel under complex thermal field conditions. Furthermore, by introducing cumulative usage time as an aging compensation parameter and jointly calculating the aging compensation coefficient with the temperature compensation coefficient, the problem of characteristic drift caused by material aging after long-term use of the liquid crystal display is solved, extending the effective service life of the product. By collecting actual display brightness in real time and comparing it with theoretical brightness, a closed-loop error feedback mechanism is formed to dynamically correct the compensation coefficients, overcoming the defect of decreasing compensation accuracy over time under open-loop control and improving the robustness and long-term reliability of the control method. This invention establishes independent voltage compensation data channels for red, green, and blue sub-pixels. Considering the differences in temperature sensitivity of different color liquid crystal materials, it achieves more precise color correction and improves display quality. Detailed Implementation

[0021] Example 1

[0022] This invention discloses a control method for a liquid crystal display, comprising the following steps:

[0023] Step 1: Obtain the image data to be displayed, and generate an initial grayscale voltage set based on the image data to be displayed.

[0024] Specifically, the timing controller of the LCD receives image data to be displayed from the system motherboard. This image data is typically a digital signal containing grayscale values ​​for three channels: red (R), green (G), and blue (B). The timing controller converts each grayscale value into a corresponding driving voltage value according to a preset standard gamma curve, thus forming an initial grayscale voltage set. This initial grayscale voltage set can achieve a standard brightness-grayscale response curve under normal temperature conditions.

[0025] Step 2: Real-time detection of the current operating temperature of the LCD panel, and generation of a grayscale voltage compensation coefficient set corresponding to the current operating temperature based on a preset temperature-compensation coefficient mapping table.

[0026] In this embodiment, multiple temperature sensors are evenly distributed in the non-display area (i.e., the bezel area) of the liquid crystal display panel. The temperature sensors can be thermistors or integrated temperature sensing chips. The timing controller periodically reads the values ​​from each temperature sensor and calculates their arithmetic mean as the current operating temperature. Subsequently, the timing controller accesses a temperature-compensation coefficient mapping table stored in non-volatile memory (such as Flash memory). This mapping table is pre-established through experimental calibration and records the voltage compensation coefficients corresponding to each grayscale level at different temperatures. The specific values ​​of the compensation coefficients reflect the amount of adjustment required to the driving voltage to compensate for the temperature effect. Based on the current operating temperature, the timing controller looks up and interpolates from the mapping table to obtain a set of grayscale voltage compensation coefficients with the same dimensions as the initial grayscale voltage set.

[0027] Step 3: Perform a gray-level superposition operation on the initial gray-level voltage set and the gray-level voltage compensation coefficient set to generate the target gray-level voltage set.

[0028] The timing controller performs a superposition operation between the initial grayscale voltage and the corresponding compensation coefficient in either the digital or analog domain. The superposition can be done using addition. It should be noted that the compensation coefficient can be positive or negative, corresponding to reducing the drive voltage to suppress overshoot in high-temperature environments or increasing the drive voltage to compensate for insufficient response in low-temperature environments, respectively.

[0029] Step 4: Drive the liquid crystal display panel to display images according to the target grayscale voltage set.

[0030] The timing controller outputs the generated target grayscale voltage set to the source driver. The source driver converts the digital signal into an analog voltage signal and applies it to the pixel electrodes of the liquid crystal display panel, driving the liquid crystal molecules to deflect to the target angle, thereby achieving a stable image display that is adapted to the current operating temperature.

[0031] Example 2

[0032] This embodiment, based on embodiment 1, further addresses the display uniformity problem caused by uneven local panel temperature.

[0033] In step two, the timing controller not only calculates the average temperature, but also monitors the difference between the values ​​collected by each temperature sensor and the average value in real time. When the difference of a certain temperature sensor exceeds a preset threshold (e.g., 5°C), it is determined that there is a local temperature anomaly in the area corresponding to that sensor, such as the temperature being too high in the area directly above the LED light strip of the backlight module, or the temperature being too low in the area with poor heat dissipation.

[0034] At this point, the timing controller divides the display panel into multiple display areas corresponding to the locations of the temperature sensors. For areas determined to be at abnormal temperatures, the timing controller independently reads the compensation coefficient corresponding to the actual temperature of that area from the temperature-compensation coefficient mapping table to generate a local target grayscale voltage set. For other normal temperature areas, the global compensation coefficient based on the average temperature is still used.

[0035] Through the above-mentioned independent compensation mechanism for each zone, this embodiment effectively solves the problem of uneven display caused by local heat sources or uneven heat dissipation, and achieves overall brightness and color uniformity of the panel.

[0036] Example 3

[0037] This embodiment adds an aging compensation function to the existing embodiment 1 to solve the problem of characteristic drift of liquid crystal materials after long-term use.

[0038] During long-term use, the liquid crystal material in a liquid crystal display (LCD) undergoes photochemical degradation or thermal aging, leading to changes in its threshold voltage and response characteristics. To compensate for this change, this embodiment pre-stores an aging compensation table in the LCD's non-volatile memory. This aging compensation table records the aging compensation coefficients corresponding to different cumulative usage durations.

[0039] Before performing the grayscale superposition operation in step three, the timing controller reads the cumulative usage time (which can be obtained by recording the device's power-on time through a real-time clock chip or counter). After obtaining the aging compensation coefficient by looking up the table based on the cumulative usage time, the initial grayscale voltage set, the grayscale voltage compensation coefficient set, and the aging compensation coefficient are jointly superimposed to generate the target grayscale voltage set.

[0040] The combined superposition operation can be performed using a weighted summation method. By introducing aging compensation, this embodiment enables the liquid crystal display to maintain stable display performance throughout its entire life cycle, thus extending the effective service life of the product.

[0041] Example 4

[0042] Based on Example 1, this embodiment introduces a closed-loop feedback correction mechanism to improve the long-term accuracy and robustness of temperature compensation.

[0043] In this embodiment, a photosensor is placed at the edge or corner of the display area of ​​the liquid crystal display panel to collect the actual display brightness of the panel in real time. While driving the display in step four, the photosensor feeds back the collected actual display brightness value to the timing controller.

[0044] The timing controller internally stores the theoretical display brightness value calculated based on the target grayscale voltage set. The difference between the actual display brightness and the theoretical display brightness is the closed-loop error. When the closed-loop error exceeds the preset tolerance, the timing controller determines that the coefficients in the current temperature-compensation coefficient mapping table are inaccurate (possibly due to temperature sensor drift, individual panel differences, or changes in environmental factors).

[0045] Based on this closed-loop error, the timing controller uses a proportional-integral-derivative (PID) control algorithm or an adaptive filtering algorithm to dynamically correct the gray-scale voltage compensation coefficient set. The corrected coefficients are fed back to update the temperature-compensation coefficient mapping table, replacing the original coefficients. Over time, this closed-loop feedback mechanism continuously iterates and optimizes the compensation coefficients, ensuring that the temperature compensation accuracy remains at a high level without the need for manual calibration.

[0046] Example 5

[0047] This embodiment refines the voltage compensation data channel based on Embodiment 1 to improve color accuracy.

[0048] Because the optical properties of the liquid crystal materials or color filters used in the red, green, and blue subpixels differ in their sensitivity to temperature, uniform compensation is insufficient to achieve optimal color reproduction. Therefore, in this embodiment, the initial grayscale voltage set, the grayscale voltage compensation coefficient set, and the target grayscale voltage set are all designed as voltage vector sets containing three independent data channels: R, G, and B.

[0049] Specifically, the temperature-compensation coefficient mapping table stores three independent sets of compensation coefficients for R, G, and B respectively. In step three, the timing controller superimposes the initial voltage of channel R with its compensation coefficient, the initial voltage of channel G with its compensation coefficient, and the initial voltage of channel B with its compensation coefficient to generate the target voltage for each channel. Through the above-mentioned independent compensation for each channel, this embodiment achieves more precise color correction, effectively avoids color shift caused by temperature changes, and significantly improves display quality.

[0050] Components not described in detail in this article are existing technologies.

[0051] While the specific embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention, and modifications or variations without creative effort are still within the protection scope of the present invention.

Claims

1. A control method for a liquid crystal display, characterized in that, The steps include the following: Step 1: Obtain the image data to be displayed, and generate an initial grayscale voltage set based on the image data to be displayed; Step 2: Real-time detection of the current operating temperature of the LCD panel, and generation of a grayscale voltage compensation coefficient set corresponding to the current operating temperature based on a preset temperature-compensation coefficient mapping table; Step 3: Perform a gray-level superposition operation on the initial gray-level voltage set and the gray-level voltage compensation coefficient set to generate the target gray-level voltage set; Step 4: Drive the liquid crystal display panel to display images according to the target grayscale voltage set.

2. The control method for a liquid crystal display according to claim 1, characterized in that: The method for real-time detection of the current operating temperature of the liquid crystal display panel described in step two specifically includes: Step 2.1: Collect temperature values ​​of different areas of the panel by using multiple temperature sensors evenly distributed in the non-display area of ​​the liquid crystal display panel; Step 2.2: Calculate the average temperature of the multiple temperature sensors as the current operating temperature.

3. The control method for a liquid crystal display according to claim 2, characterized in that: Also includes: When the difference between the temperature value collected by any of the temperature sensors and the average temperature exceeds a preset threshold, it is determined that the panel has a local temperature abnormality. In step three, a local target grayscale voltage set is independently generated for the display area corresponding to the temperature sensor in order to perform independent voltage compensation driving on the display area.

4. The control method for a liquid crystal display according to claim 1, characterized in that: The preset temperature-compensation coefficient mapping table is established in advance by measuring the deviation curve between the actual transmittance and the target transmittance of the liquid crystal display panel at different ambient temperatures. Based on the deviation curve, the compensation coefficient of each gray level at different temperatures is calculated by the reverse interpolation algorithm and then stored in the non-volatile memory of the liquid crystal display.

5. The control method for a liquid crystal display according to claim 1, characterized in that: Before the gray-level superposition operation in step three, the method further includes: obtaining the cumulative usage time of the liquid crystal display panel; obtaining the aging compensation coefficient from the preset aging compensation table based on the cumulative usage time; and performing a joint superposition operation on the aging compensation coefficient, the initial gray-level voltage set, and the gray-level voltage compensation coefficient set to generate the target gray-level voltage set.

6. The control method for a liquid crystal display according to claim 1, characterized in that: It also includes, after step four, real-time acquisition of the actual display brightness of the liquid crystal display panel; comparison of the actual display brightness with the theoretical display brightness calculated based on the target grayscale voltage set, and calculation of the closed-loop error; The grayscale voltage compensation coefficient set is dynamically corrected based on the closed-loop error, and the corrected coefficients are fed back to update the preset temperature-compensation coefficient mapping table.

7. The control method for a liquid crystal display according to claim 1, characterized in that: The initial grayscale voltage set, the grayscale voltage compensation coefficient set, and the target grayscale voltage set are all voltage vector sets containing independent data channels of red sub-pixels, green sub-pixels, and blue sub-pixels.