Display device and driving method thereof

Abstract

The invention provides a display device and a driving method thereof, and the display device comprises a display module which comprises a time schedule controller and a display panel which are electrically connected; the backlight module comprises a backlight driving circuit and a light-emitting unit which are electrically connected, and the backlight driving circuit is used for driving the light-emitting unit to emit light; the control module is electrically connected with the backlight module and the display panel; the control module is configured to analyze a frame image in a received video signal to obtain sub-field pixel data and sub-field backlight data; and generating the liquid crystal driving signal and the backlight driving signal according to the sub-pixel data and the sub-field backlight data, and sending the liquid crystal driving signal and the backlight driving signal to the time schedule controller and the backlight driving circuit. According to the method, the gray-scale value of the input data is mapped, the color depth of field order display is improved, and the time crosstalk problem is optimized.

Description

Technical Field

[0001] This invention relates to the field of display device technology, and in particular to a display device and a driving method for the display device. Background Technology

[0002] Field Sequential Color (FSC) is a display technology based on time-sequential color mixing. It synthesizes a full-color image by switching the three primary colors of light (red, green, and blue) in a time-division manner and utilizing the persistence of vision in the human eye. Its core principle lies in replacing the traditional RGB sub-pixel arrangement with a monochrome display panel (such as a single liquid crystal layer or micromirror array). It eliminates the need for traditional color filters and achieves color reproduction through high-speed time-sequential control, offering advantages such as high luminous efficiency and improved resolution.

[0003] In related technologies, the field-sequence display algorithm divides a frame of image into three sub-fields according to red (R), green (G), and blue (B). Each color forms a display sub-field, and the value of each sub-pixel in the pixel is set to be consistent. Each sub-field uses 8 bits of data to represent brightness. Since each color channel only has a grayscale range of 256 levels, it is easy to cause uneven color transitions, limited dynamic range, color banding or breaks in gradient areas, loss of detail, and visual fatigue, making it difficult to meet the application requirements of high image quality, HDR, and high-precision color reproduction.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, according to embodiments of this disclosure, a display device is proposed, comprising: The display module includes a timing controller and a display panel that are electrically connected; A backlight module includes an electrically connected backlight driving circuit and a light-emitting unit, wherein the backlight driving circuit is used to drive the light-emitting unit to emit light; The control module is electrically connected to the backlight module and the display panel; The control module is configured as follows: The frame images in the received video signal are analyzed to obtain subfield pixel data and subfield backlight data; Based on the subfield backlight data corresponding to the frame image, a backlight driving signal is generated and sent to the backlight driving circuit. The initial grayscale value of the first pixel of the subfield pixel data is mapped to the target grayscale value in the target grayscale mode, wherein the initial grayscale value is the grayscale value in the first grayscale mode, the maximum grayscale value in the target grayscale mode is N times 255, and one pixel on the display panel includes N sub-pixels. The sub-grayscale values ​​of N sub-pixels corresponding to the first pixel are determined based on the target grayscale value of the first pixel, wherein the sum of the sub-grayscale values ​​of the N sub-pixels is equal to the target grayscale value of the first pixel. The liquid crystal driving signal is generated based on the N sub-grayscale values ​​and sent to the timing controller; The timing controller is used to generate a timing signal based on the received liquid crystal driving signal and send it to the display panel. The display panel is used to adjust the driving voltage of N sub-pixels corresponding to the first pixel point according to the timing signal and display the frame image.

[0007] Based on the above configuration, the control module of this application extracts sub-field pixel data and sub-field backlight data from the frame image. The control module maps the initial grayscale value to the target grayscale value. The target grayscale value has higher accuracy than existing conventional grayscale values. At the same time, the target grayscale value of the first pixel is displayed by accumulating the sub-grayscale values ​​of N sub-pixels, with an equivalent bit depth. The increase significantly improved the image detail reproduction and brightness control accuracy of display devices.

[0008] In some embodiments, mapping the initial grayscale value of the first pixel of the subfield pixel data to the target grayscale value in the target grayscale mode includes: Based on the first conversion coefficient from the first grayscale mode to the target grayscale mode, the product of the first conversion coefficient and the initial grayscale value is calculated to determine the target grayscale value under the target grayscale mode; Wherein, the first conversion coefficient is the ratio of the maximum gray level value of the target gray level mode to the maximum gray level value of the first gray level mode.

[0009] Based on this, the initial grayscale value is directly mapped to the grayscale value range of the target grayscale mode by utilizing the linear proportional relationship between grayscale modes. Since this conversion relationship is a linear mapping, it can ensure that the relative brightness ratio of the original grayscale is preserved during the grayscale value transformation process, avoiding nonlinear distortion.

[0010] In some embodiments, the control module pre-stores the effective grayscale values ​​of the pixels of the display panel in the target grayscale mode, and the step of mapping the initial grayscale value of the first pixel of the subfield pixel data to the target grayscale value in the target grayscale mode includes: Based on the second conversion coefficient from the first grayscale mode to the target grayscale mode, the product of the second conversion coefficient and the initial grayscale value is calculated to determine the target grayscale value under the target grayscale mode; Wherein, the effective grayscale value is lower than the maximum grayscale value of the target grayscale mode and higher than the maximum grayscale value of the first grayscale mode, and the second conversion coefficient is the ratio of the effective grayscale value of the target grayscale mode to the maximum grayscale value of the first grayscale mode.

[0011] Based on the above configuration, the above embodiment introduces an effective grayscale value to optimize the upper limit of the target grayscale mode mapping, instead of directly using the theoretical maximum grayscale value, thereby avoiding nonlinear response and color shift when the panel driver approaches the saturation area. This strategy takes into account both brightness utilization and image quality stability.

[0012] In some embodiments, determining the N sub-grayscale values ​​corresponding to the first pixel based on the target grayscale value of the first pixel includes: The mean of the target grayscale value is calculated based on the number of sub-pixels N, and then rounded down to obtain a base value. This base value is then distributed to each sub-pixel. The target grayscale value is moduloed based on the number of sub-pixels to obtain the remainder. The remainder is then allocated to at least one sub-pixel, and the allocated sub-grayscale value is output.

[0013] Based on the above configuration, an allocation strategy combining integer division and modulo is adopted to accurately decompose the target grayscale value into N sub-grayscale values, ensuring that their sum equals the target grayscale value. Based on average calculation and remainder allocation, the brightness difference of sub-pixels is almost imperceptible to the human eye, reducing color difference artifacts between sub-pixels.

[0014] In some embodiments, the control module is configured to include: The target grayscale value is determined based on a first lookup table, which contains N sub-grayscale values. The first lookup table stores a first mapping relationship between a target grayscale value and its corresponding sub-grayscale values. The sum of the sub-grayscale values ​​is the target grayscale value, and the difference between any two sub-grayscale values ​​is an integer not exceeding 1.

[0015] The above embodiments improve mapping speed and stability by pre-establishing a mapping relationship between target grayscale values ​​and sub-grayscale values, thus avoiding division and modulo operations during runtime. This first lookup table can be stored in a high-speed memory (such as SRAM). After receiving the target grayscale value, the control module directly indexes the lookup table to obtain the corresponding N sub-grayscale values, thereby completing the mapping in O(1) time complexity.

[0016] In some embodiments, the control module is configured to include: The expected values ​​of N sub-grayscale values ​​are determined based on a second lookup table, and the liquid crystal driving signal is generated based on the expected values ​​of the N sub-grayscale values ​​and sent to the timing controller. The second lookup table stores a second mapping relationship between N sub-grayscale values ​​and their corresponding expected values.

[0017] In some embodiments, the control module is configured to include: Determine whether the first horizontal gradient and the second horizontal gradient of the first pixel and its left and right adjacent pixels have the same direction and whether the difference between them is less than a gradient threshold. If so, the second mapping relationship is: the expected values ​​corresponding to the N sub-grayscale values ​​conform to a linear relationship, which is determined based on the grayscale values ​​of the left adjacent pixel and the grayscale values ​​of the right adjacent pixel; Otherwise, the second mapping relationship is: the N sub-grayscale values ​​conform to the distribution of a non-linear curve, which is determined based on the grayscale values ​​of the left adjacent pixel and the right adjacent pixel.

[0018] In the above embodiments, by analyzing the grayscale change trend of the target pixel and its neighboring pixels in the horizontal direction, a linear or non-linear mapping strategy is dynamically selected to optimize the expected driving of the sub-grayscale values. Linear mapping is used in smooth areas to maintain a natural brightness transition; non-linear distribution is used in high gradient areas to enhance detail contrast and reduce edge blur.

[0019] In some embodiments, the control module pre-stores a compensation coefficient, and the generation of the backlight driving signal based on the sub-field backlight data corresponding to the frame image specifically includes: The subfield brightness value is determined based on the subfield backlight data, the subfield brightness value is compensated by calculating the product of the subfield brightness value and the compensation coefficient, and the compensated backlight driving signal is output based on the compensated subfield brightness value. The compensation coefficient is the ratio of the maximum grayscale value of the pixel in the target grayscale mode to the effective grayscale value.

[0020] The above embodiments provide a way to correct insufficient brightness caused by the limitation of effective grayscale values ​​by introducing a compensation coefficient during the backlight driving process. The brightness compensation is applied to the backlight layer and does not change the pixel grayscale distribution. Therefore, while maintaining a large dynamic range in dark areas, it improves the peak output of bright scenes, thereby improving contrast. Moreover, the compensation only adjusts the backlight brightness, avoiding the risk of over-driving and color shift at the pixel driving end.

[0021] In some embodiments, the control module determines the compensated subfield brightness value based on the subfield brightness value and a third lookup table, and generates a backlight drive signal based on the compensated subfield brightness value. The third lookup table stores a third mapping relationship between subfield brightness values ​​and compensated subfield brightness values. The third mapping relationship is to compensate the subfield brightness value by calculating the product of the subfield brightness value and a compensation coefficient. The compensation coefficient is the ratio of the maximum grayscale value of the pixel in the target grayscale mode to the effective grayscale value.

[0022] The above embodiment implements backlight compensation calculation through a lookup table, avoiding the delay caused by real-time multiplication. The third lookup table is generated during the system's factory or calibration phase. During operation, the control module reads the current subfield brightness value, directly indexes the third lookup table to obtain the compensated brightness value, and then generates a backlight drive signal based on the compensated brightness value and outputs it to the backlight drive circuit, thereby achieving brightness restoration and compensation at the backlight layer.

[0023] In addition, this application also discloses a driving method for a display device, including: Acquire the video signal to be displayed on the display device; Subfield pixel data and subfield backlight data are obtained by analyzing the video signal. The initial grayscale value of the first pixel of the subfield pixel data is mapped to the target grayscale value in the target grayscale mode. The initial grayscale value is the grayscale value in the first grayscale mode. The maximum grayscale value of the first grayscale mode is 255. The maximum grayscale value in the target grayscale mode is N times 255. One pixel on the display panel includes N sub-pixels. The sub-grayscale values ​​of N sub-pixels corresponding to the first pixel are determined based on the target grayscale value of the first pixel, wherein the sum of the sub-grayscale values ​​of the N sub-pixels is equal to the target grayscale value of the first pixel. A liquid crystal driving signal is generated based on the N sub-grayscale values, and a backlight driving signal is generated based on the sub-field backlight data. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a field sequence display module in the prior art; Figure 2 This is a structural block diagram of pixels according to an embodiment of this application; Figure 3 This is a structural block diagram of a display device according to an embodiment of this application; Figure 4 This is a schematic diagram of the structure of a display device provided in an embodiment of this application; Figure 5 This is a timing diagram of the control logic according to an embodiment of this application; Figure 6 It is based on the sub-field refresh timing diagram of the example display panel; Figure 7This is another structural block diagram of a display device according to an embodiment of this application; Figure 8 This is another structural block diagram of the display device according to an embodiment of this application; Figure 9 This is another timing diagram of the control logic according to the embodiments of this application; Figure 10 This is another structural block diagram of a display device according to an embodiment of this application; Figure 11 This is a flowchart illustrating the driving method according to an embodiment of this application.

[0025] In the above figures: 1. Backlight; 2. Lower polarizer; 3. Glass plate; 4. Thin-film transistor array; 5. Liquid crystal layer; 6. Glass plate; 7. Upper polarizer; 10. Display module; 20. Backlight module; 30. Control module; 11. Timing controller; 12. Display panel; 21. Backlight driving circuit; 22. Light-emitting unit. Detailed Implementation

[0026] To make the objectives and implementation methods of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the exemplary embodiments described are only some embodiments of this application, and not all embodiments.

[0027] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0028] The terms "first," "second," "third," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar or related objects or entities, and do not necessarily imply a specific order or sequence, unless otherwise specified. It should be understood that such terms are interchangeable where appropriate.

[0029] The terms “comprising” and “having”, and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device that includes a range of components is not necessarily limited to all of the components that are clearly listed, but may include other components that are not clearly listed or that are inherent to such product or device.

[0030] Field-sequence display technology divides a frame of image into three sub-fields: red (R), green (G), and blue (B). Each sub-field displays only the image of the current color component (e.g., the red field only displays the red channel information). In conjunction with the sub-field timing, backlight or light source components (such as LEDs / lasers) cycle through the R / G / B colors at millisecond speeds. When the switching frequency exceeds the critical flicker frequency of the human eye (typically >60Hz), the human brain automatically merges the continuous three-color images into a full-color image.

[0031] However, the mismatch between the liquid crystal molecule flipping speed and the high refresh rate requirement leads to time crosstalk and color shift when mixing three colors. Figure 1 This is a schematic diagram of a field-sequence display module structure in the prior art, which may include a backlight 1, a lower polarizer 2, a glass plate 3, a thin-film transistor array 4, a liquid crystal layer 5 (LC), a glass plate 6, and an upper polarizer 7.

[0032] refer to Figure 1 As shown, the backlight 1 typically includes LEDs or other light sources, as well as optical components such as light guide plates and brightness enhancement films, which are responsible for providing a uniform and rapidly switchable light source.

[0033] The lower polarizer 2 is the first optical film located above the backlight. The function of the polarizer is to allow light vibrating in a specific direction to be converted into linearly polarized light by the natural light emitted from the backlight (vibrating in all directions), thus preparing for the subsequent "light valve" regulation of the liquid crystal molecules.

[0034] Glass plates 3 and 6 form two upper and lower glass substrates, constituting the two side bases of the liquid crystal cell. A thin-film transistor array 4 is fabricated on glass plate 3. The thin-film transistor array 4 acts as a "switch" for each sub-pixel, changing the twist angle of the liquid crystal molecules by controlling the voltage of each sub-pixel. The thin-film transistor array 4 consists of multiple pixels, and each pixel consists of multiple sub-pixels. This application uses three sub-pixels as an example; the pixel configuration is as follows... Figure 2 As shown, each pixel includes a first sub-pixel1, a second sub-pixel2, and a third sub-pixel3.

[0035] The liquid crystal layer 5, located between glass plates 3 and 6, controls the torsion of liquid crystal molecules via the voltage of a thin-film transistor array, determining how much light energy passes through the lower polarizer 2 and reaches the upper polarizer 7. The upper polarizer 7 is a polarizing film located above the liquid crystal layer. The polarization direction of the upper polarizer 7 is perpendicular to that of the lower polarizer (or at other angles depending on the design, but usually orthogonal). Only light modulated by the liquid crystal layer 5 and whose polarization direction is consistent with the allowed direction of the upper polarizer 7 can pass through the upper polarizer 7 and ultimately be seen by the human eye.

[0036] Taking the conventional R, G, and B three-field alternating display as an example, the existing field sequence display algorithm decomposes an image according to RGB colors, with each color forming a display subfield. In each display subfield, the backlight is set to R, G, or B, and the pixel is set to the transmittance of the image under a specific backlight. The value of each sub-pixel in the pixel is set to be consistent, that is, all sub-pixels need to be synchronously adjusted to allow the current color light to pass through. The sub-pixel driving voltage is uniformly set to the set grayscale value (0~255).

[0037] Modern high-definition display standards (such as HDR10, Dolby Vision, and HDR10+) typically require a 10-bit color depth (or even 12-bit). Therefore, although conventional field-sequence display algorithms are simple to control, they cannot effectively utilize the flexible control of subpixels. The effective grayscale values ​​that can be displayed are limited to 0~255. They have significant shortcomings in terms of color transition, dynamic range, HDR support, and visual comfort, making it difficult to meet the needs of high-end display applications.

[0038] To improve the color depth of field sequence displays and optimize the time crosstalk problem, this application proposes a display device and its driving method. The display device and its driving method according to the embodiments of this application are described below with reference to the accompanying drawings.

[0039] In this application embodiment, "display device" refers to any device with screen display and data processing capabilities. For example, display devices include, but are not limited to, smart TVs, mobile terminals, computers, monitors, advertising screens, wearable devices, virtual reality devices, and augmented reality devices.

[0040] Figure 3 This is a schematic diagram of the structure of a display device according to an embodiment of this application. (Reference) Figure 3 As shown, the display device may include a display module 10 and a backlight module 20, with the display module 10 located at the light-emitting side of the backlight module 20, and the display module 10 used for image display.

[0041] Figure 4 This is a schematic diagram of a display device provided in an embodiment of this application. (Reference) Figure 4 As shown, the display module 10 may include a timing controller 11 and a display panel 12 that are electrically connected.

[0042] The backlight module 20 includes an electrically connected backlight driving circuit 21 and multiple light-emitting units 22. The backlight driving circuit 21 is used to drive the light-emitting units to emit light.

[0043] The display device may also include a control module 30, which is connected to the backlight driving circuit 21 of the display module 10 and the backlight module 20, respectively.

[0044] In some embodiments, no color filter is provided in the display panel.

[0045] The above sections have provided a schematic illustration of the display device's structure. The following section, with reference to the accompanying drawings, explains the processing logic of the control module.

[0046] refer to Figure 5 As shown, the control module 30 is configured to parse the frame image in the received video signal to obtain subfield pixel data, and to perform color dimming processing on the frame image to obtain subfield backlight data (step S101). The frame data of the frame image includes polarity duration.

[0047] The control module 30 can be configured to include a processor. The video signal refers to the raw video stream signal from the video source. In this embodiment, the television software system can synchronize and process image frames through a hardware interrupt mechanism. Specifically, whenever the television generates a frame, an interrupt is triggered, notifying the processor that a new frame needs to be processed. Then, the processor executes the defined display driver method in the corresponding interrupt service function.

[0048] In practice, the processor can receive video signals through the interface of the display device, use a video decoder to decode the video signals into digital image format, trigger an interrupt when generating a frame image, and then obtain the frame data of the current frame image, including polarity duration, polarity state, brightness information, voltage information and timestamp, and save the frame data to an array for subsequent processing.

[0049] In some embodiments, the control module 30 is further configured to generate a backlight driving signal based on the sub-field backlight data corresponding to the frame image and send it to the backlight driving circuit (step S102). In specific implementation, the processor can determine the driving signal corresponding to each sub-field according to the sub-field backlight data and preset mapping data. The preset mapping data includes data on the correspondence between the standard backlight average value of each sub-field and the backlight driving signal current, and sends the backlight driving signal corresponding to each sub-field to the backlight driving circuit 21.

[0050] In some embodiments, the backlight driving circuit 21 drives the light-emitting unit 22 in response to the backlight driving signal (step S104).

[0051] In some embodiments, the control module 30 may use a 180Hz-Stencil algorithm to parse the frame image and obtain the aforementioned subfield pixel data.

[0052] In some embodiments, the control module 30 may include a main control chip (SOC) for performing operations such as format conversion, data processing, image rendering, and protocol conversion on the input target image to generate intermediate display data. The main control chip transmits the generated intermediate display data to the timing controller 11. The timing controller 11 processes the intermediate display data and outputs the processed liquid crystal driving signal to the display panel 12.

[0053] In some embodiments, the control module 30 may be configured to generate a liquid crystal driving signal based on subfield pixel data and send it to the timing controller 11 of the display module 10.

[0054] In some embodiments, the timing controller 11 may be configured to map the liquid crystal driving signal to the position of the liquid crystal molecules so that the liquid crystal driving signal obtained by the display panel 10 corresponds to the data to be displayed, thereby ensuring the accuracy of the display.

[0055] In some embodiments, generating a liquid crystal driving signal based on subfield pixel data specifically includes: mapping the initial grayscale value of the first pixel point of the subfield pixel data to the target grayscale value under the target grayscale mode; determining the sub-grayscale values ​​of N sub-pixels corresponding to the first pixel point according to the target grayscale value of the first pixel point, wherein the sum of the sub-grayscale values ​​of the N sub-pixels is equal to the target grayscale value of the first pixel point; generating a liquid crystal driving signal based on the N sub-grayscale values ​​and sending it to the timing controller.

[0056] The initial grayscale value is the grayscale value in the first grayscale mode. The maximum grayscale value in the first grayscale mode can be any one of 255, 1023, and 4095. If the maximum grayscale value is 255, it means that the first pixel is 8-bit deep pixel data. If the maximum grayscale value is 1023, it means that the first pixel is 10-bit deep pixel data. If the maximum grayscale value is 4095, it means that the first pixel is 12-bit deep pixel data. It is not limited to these values.

[0057] In the target grayscale mode, the maximum grayscale value is N times 255, and one pixel on the display panel consists of N sub-pixels. Figure 1 Taking the display panel shown as an example, the corresponding number of sub-pixels N is 3; In some embodiments, the timing controller 11 is used to generate a timing signal based on the received liquid crystal driving signal and send it to the display panel (step S105). The display panel is used to adjust the driving voltage of N sub-pixels corresponding to the first pixel point according to the timing signal and display the frame image.

[0058] In some embodiments, N sub-pixels corresponding to the first pixel are driven simultaneously, such that the sum of the sub-grayscale values ​​of the N sub-pixels displayed on the user side is equal to the target grayscale value of the first pixel.

[0059] It should be noted that in the above embodiments, steps S101 to S105 are not limited to being executed sequentially. For example, steps S102 and S103 can be configured to be executed in parallel.

[0060] Based on the above configuration, the control module processes the backlight data to generate corresponding backlight driving signals, controlling the backlight driving circuit to drive the light-emitting units as needed, thereby adjusting the brightness and color temperature. Simultaneously, by mapping the initial grayscale value of the first pixel to the target grayscale value under the target grayscale mode, and calculating the sub-grayscale values ​​of each sub-pixel based on the target grayscale value, these sub-grayscale values ​​are converted into liquid crystal driving signals and sent to the timing controller. The timing controller generates precise timing signals to drive the display panel based on the liquid crystal driving signals. Compared to the prior art where N sub-pixels are driven to display the same grayscale value directly based on the initial grayscale value, this application maps the initial grayscale value of the first pixel to the target grayscale value under the target grayscale mode, and presents the target grayscale value of the first pixel by accumulating the sub-grayscale values ​​of N sub-pixels. Under the premise of equal liquid crystal sub-pixel capabilities, displaying by accumulating the sub-grayscale values ​​of N sub-pixels increases the bit depth of a pixel. This achieves fine control of the sub-pixel voltage, enabling the frame image to be displayed with higher grayscale accuracy and brightness matching. Synchronized control of backlight drive and pixel drive also improves image contrast and dynamic performance.

[0061] In this application, the control module 30 extracts sub-field pixel data and sub-field backlight data from the frame image. The control module maps the initial grayscale value to the target grayscale value. The target grayscale value has higher accuracy than existing conventional grayscale values, with an equivalent bit depth of [missing information]. With the increase in N=3, the equivalent bit depth is 9.58, meaning that the display device of this application can display an equivalent bit depth greater than 8 bits, which significantly improves the image detail reproduction and brightness control accuracy of the display device.

[0062] In the above embodiments, the control module 30 maps the initial grayscale value of the first pixel of the subfield pixel data to the target grayscale value in the target grayscale mode by: calculating the product of the first conversion coefficient and the initial grayscale value based on the first conversion coefficient from the first grayscale mode to the target grayscale mode, and determining the target grayscale value in the target grayscale mode; wherein, the first conversion coefficient is the ratio of the maximum grayscale value of the target grayscale mode to the maximum grayscale value of the first grayscale mode.

[0063] Based on this, the initial grayscale value is directly mapped to the grayscale value range of the target grayscale mode using the linear proportional relationship between grayscale modes. Specifically, the maximum grayscale value of the target grayscale mode is 255×N. For example, but not limited to, the maximum grayscale value of the first grayscale mode is 4095. The ratio of the two is the first conversion coefficient K. Multiplying the initial grayscale value G_in by K yields the target grayscale value G_out = K·G_in. Because this conversion relationship is a linear mapping, it ensures that the relative brightness ratio of the original grayscale levels is preserved during the grayscale value transformation process, avoiding nonlinear distortion.

[0064] In the above embodiments, the first conversion coefficient can be pre-stored in a register, EEPROM or Flash memory, or it can be calculated in real time by the control module when switching modes.

[0065] In the above implementation, the mapping method can be extended to nonlinear mapping, for example, introducing gamma correction in near-complete black or complete white areas to optimize visual perception.

[0066] In another embodiment, considering that time crosstalk is quite serious in field sequence display and greatly affects the display effect, this embodiment limits the target grayscale mode to an effective range.

[0067] Specifically, the control module 30 pre-stores the effective grayscale values ​​of the display panel's pixels in the target grayscale mode, and maps the initial grayscale value of the first pixel of the subfield pixel data to the target grayscale value in the target grayscale mode, including: Based on the second conversion coefficient from the first grayscale mode to the target grayscale mode, the product of the second conversion coefficient and the initial grayscale value is calculated to determine the target grayscale value under the target grayscale mode; Wherein, the effective grayscale value is lower than the maximum grayscale value of the target grayscale mode and higher than the maximum grayscale value of the first grayscale mode, and the second conversion coefficient is the ratio of the effective grayscale value of the target grayscale mode to the maximum grayscale value of the first grayscale mode.

[0068] In some of these embodiments, Figure 6 For example, in this embodiment of the application, the effective grayscale values ​​of the pixels of the display panel are determined based on the sub-field refresh timing diagram. (See reference...) Figure 6 As shown, the sub-field refresh cycle is 240Hz (4.2ms), the black frame insertion time is 2.1ms, and the backlight illumination time of the three sub-fields is T. BL_on The respective times are 2.1ms.

[0069] The flip curve represents the change in transmittance of liquid crystal molecules over time under voltage driving (e.g., Figure 6(As shown in the black curve). Typically, when a voltage is applied, the liquid crystal molecules begin to flip, and the transmittance gradually increases (for the black mode) or decreases (for the white mode) until a stable state is reached.

[0070] Black frame insertion technology is used to insert a brief black screen between backlight switching to isolate different color scenes.

[0071] Therefore, under a specific refresh cycle and black frame insertion time, the intersection of the pixel at the rising edge of the first sub-field backlight drive signal and the flip curve is point A, and the intersection at the falling edge of the first sub-field backlight drive signal and the flip curve is point B. If the transmittance difference between points A and B is less than a specific threshold, such as 2%, then the grayscale value at point A is considered to be stable within the sub-field backlight illumination time, and the grayscale value at point A is the effective value of the sub-pixel (DR). 有效 ).

[0072] The effective grayscale value of the target grayscale mode is calculated based on the effective value of the sub-pixels. Among N sub-pixels, m sub-pixels can satisfy the grayscale value at point A above, that is, the maximum dynamic range of the sub-pixels is the maximum grayscale value without distortion under the current duty cycle. The maximum dynamic range of Nm sub-pixels exceeds this maximum grayscale value, but is less than 255. Let the excess ratio be COFF.

[0073] The effective grayscale range DR of this pixel is determined based on the scaling factor COFF. use It is the sum of the maximum grayscale values ​​of N sub-pixels, i.e.: DR use =m*DR 有效 +(Nm)*DR 有效 *COFF. Optional. The scaling factor COFF is determined based on the overall acceptable time crosstalk error. The smaller the required error, the closer this value is to 1, such as 1.2.

[0074] Within the effective grayscale range, the effective grayscale value is DR. use -1.

[0075] Taking a case where two of the three sub-pixels have a dynamic maximum value that is the maximum grayscale value without distortion under the current duty cycle, specifically 180, and the dynamic maximum value of the other sub-pixel is greater than 180, then the effective grayscale value of the three sub-pixels is 576.

[0076] Taking 8-bit pixel data as an example, its pixel value in the first grayscale mode is 160, and after conversion based on the second conversion coefficient, it becomes 361. The second conversion coefficient is 575 / 255.

[0077] In some embodiments, the effective grayscale value varies under different temperatures and duty cycles. During the factory or calibration phase, the control module 30 determines the mapping relationship between temperature, duty cycle, and effective grayscale value, and pre-stores the effective grayscale value of the display panel 12 in the internal storage unit under the target grayscale mode.

[0078] The control module 30 can be configured to connect to a temperature acquisition module in a display device. The temperature acquisition module is used to determine the temperature value so that the control module 30 can determine the corresponding effective grayscale value based on the temperature value and the duty cycle.

[0079] Based on the above configuration, an effective grayscale value is introduced to optimize the mapping upper limit of the target grayscale mode, instead of directly using the theoretical maximum grayscale value, thereby avoiding nonlinear response and color shift when the panel driver approaches the saturation region. The control module 30 calculates the second conversion coefficient K2 = (DR) based on this effective grayscale value. use -1) / G_max1 (where G_max1 is the maximum gray level value of the first gray level mode, usually 255).

[0080] During operation, the initial grayscale value G_in is multiplied by K2 to obtain the target grayscale value G_out = K2·G_in, thereby ensuring that the maximum output brightness after grayscale mapping does not exceed the optimal usable range of the panel. This strategy balances brightness utilization and image quality stability, especially reducing the risk of panel color shift and overshoot in high-brightness areas.

[0081] In some embodiments, determining the N sub-grayscale values ​​corresponding to the first pixel based on the target grayscale value of the first pixel includes: The mean of the target grayscale value is calculated based on the number of sub-pixels N, and then rounded down to obtain a base value. This base value is then distributed to each sub-pixel. The target grayscale value is moduloed based on the number of sub-pixels to obtain the remainder. The remainder is then allocated to at least one sub-pixel, and the allocated sub-grayscale value is output.

[0082] Taking the target grayscale value of the first pixel after conversion as 361 as an example, the base value of its three sub-pixels is configured as 120. After the remainder is allocated, the three sub-pixels can be configured as (120, 120, 121).

[0083] Based on the above configuration, an allocation strategy combining integer division and modulo is adopted to accurately decompose the target grayscale value into N sub-grayscale values, ensuring that their sum equals the target grayscale value. Based on average calculation and remainder allocation, the brightness difference of sub-pixels is almost imperceptible to the human eye, reducing color difference artifacts between sub-pixels.

[0084] refer to Figure 7 As shown, the control module 30 is configured to include: Based on a first lookup table LUT1, determine the N sub-grayscale values ​​corresponding to the target grayscale value. The first lookup table LUT1 stores a first mapping relationship between a target grayscale value and its corresponding sub-grayscale values. The sum of the sub-grayscale values ​​is the target grayscale value, and the difference between any two sub-grayscale values ​​is an integer not exceeding 1.

[0085] The above embodiments improve mapping speed and stability by pre-establishing a mapping relationship between target grayscale values ​​and sub-grayscale values, thus avoiding division and modulo operations during runtime. This first lookup table can be stored in a high-speed memory (such as SRAM). After receiving the target grayscale value, the control module directly indexes the lookup table to obtain the corresponding N sub-grayscale values, thereby completing the mapping in O(1) time complexity.

[0086] In the above implementation, the first lookup table LUT1 is stored in the control module 30.

[0087] The control module 30 is configured to include on-chip cache, external high-speed memory, or non-volatile memory (such as NOR Flash), with a trade-off between access frequency and power consumption requirements. The mapping relationship can be generated based on a simple mean allocation method, or optimized by incorporating the panel's photoelectric characteristics, such as adjusting the allocation ratio according to the luminous efficiency weights of RGB sub-pixels. To save storage space, only the allocation results corresponding to a portion of the grayscale values ​​can be stored, with the remaining values ​​obtained through interpolation to balance access speed and storage capacity.

[0088] refer to Figure 8 As shown, the control module 30 is configured to include: The expected values ​​of N sub-grayscale values ​​are determined based on a second lookup table (LUT2). The liquid crystal driving signal is generated based on the expected values ​​of the N sub-grayscale values ​​and sent to the timing controller. The second lookup table LUT2 stores the second mapping relationship between N sub-grayscale values ​​and their corresponding expected values.

[0089] In some embodiments, the control module 30 is configured to include: Determine whether the first horizontal gradient and the second horizontal gradient of the first pixel are in the same direction as its left and right adjacent pixels, and whether the difference between them is less than a gradient threshold. If so, the second mapping relationship is: the expected values ​​corresponding to the N sub-grayscale values ​​conform to a linear relationship, which is determined based on the grayscale values ​​of the left adjacent pixel and the grayscale values ​​of the right adjacent pixel; Otherwise, the second mapping relationship is: the N sub-grayscale values ​​conform to the distribution of a non-linear curve, which is determined based on the grayscale values ​​of the left adjacent pixel and the right adjacent pixel.

[0090] In the above embodiment, the control module 30 calculates the grayscale difference ΔL between the target pixel and its left neighboring pixel as the first horizontal gradient; and calculates the grayscale difference ΔR between the target pixel and its right neighboring pixel as the second horizontal gradient. If ΔL and ΔR have the same sign (indicating consistent gradient directions) and |ΔL-ΔR| is lower than a preset gradient threshold (indicating similar change magnitudes), then the current pixel is considered to be in a smooth brightness transition region, and the expected values ​​of N sub-grayscale values ​​are interpolated and distributed among adjacent pixels using a linear relationship. Otherwise, it is determined to be an edge or texture region, and a non-linear curve is used for distribution, concentrating the sub-grayscale values ​​at sub-pixel positions with rapid brightness changes to enhance local contrast.

[0091] By analyzing the grayscale variation trend of the target pixel and its neighboring pixels in the horizontal direction, a linear or non-linear mapping strategy is dynamically selected to optimize the expected driving force of sub-grayscale values. Linear mapping is used in smooth areas to maintain a natural brightness transition, while non-linear distribution is used in high gradient areas to enhance detail contrast and reduce edge blur.

[0092] The second lookup table LUT2 stores the pre-calculated results of both linear and nonlinear mapping curves. The control module can directly select the corresponding curve based on the detection results to determine the expected value.

[0093] In some embodiments, the nonlinear curve may be implemented using Gamma, S-curve, or piecewise polynomial functions to adapt to the visual characteristics of different types of content.

[0094] In another embodiment, considering that the target grayscale value is lower than the target grayscale value obtained by conversion based on the first conversion coefficient after the controller limits the target grayscale value based on the effective grayscale value, the contribution of the actual usable grayscale range to the brightness improvement is limited. Therefore, it is necessary to compensate for the defects caused by the reduction of panel grayscale by stronger backlight brightness, so that the overall picture can maintain the required brightness and contrast.

[0095] To achieve the above objectives, the control module 30 pre-stores a compensation coefficient and generates a backlight driving signal based on the sub-field backlight data corresponding to the frame image, specifically including: The subfield brightness value is determined based on the subfield backlight data, and the subfield brightness value is compensated by calculating the product of the subfield brightness value and the compensation coefficient (step S1021). The compensated backlight driving signal is output based on the compensated subfield brightness value (step S1022). The compensation coefficient is the ratio of the maximum grayscale value of the pixel in the target grayscale mode to the effective grayscale value.

[0096] First, the brightness value L_sub of the current subfield is calculated from the subfield backlight data; then, L_sub is multiplied by the compensation coefficient K_comp to obtain the compensated brightness value L_comp = K_comp × L_sub; finally, the corresponding backlight drive signal is generated based on L_comp and output to the backlight drive circuit. The compensation coefficient K_comp is calculated as the ratio of the maximum grayscale value (e.g., 255 × N) of the target grayscale mode to the effective grayscale value.

[0097] Taking an effective grayscale value of 575 as an example, if the maximum grayscale value of the three sub-pixels is 765, then the compensation coefficient is 765 / 575.

[0098] The above embodiments provide a method to correct insufficient brightness caused by limitations in effective grayscale values ​​by introducing a compensation coefficient during the backlight driving process. Since the effective grayscale value is lower than the theoretical maximum value, the compensation coefficient is usually greater than 1, thereby increasing the brightness on the backlight side to compensate for the insufficient light output caused by grayscale compression on the panel side.

[0099] Brightness compensation is applied to the backlight layer and does not change the pixel grayscale distribution. Therefore, while maintaining a large dynamic range in dark areas, it improves the peak output in bright scenes, thereby improving contrast. Moreover, the compensation only adjusts the backlight brightness, avoiding the risk of over-driving and color shift at the pixel driver end.

[0100] In the above implementation, the compensation operation can be implemented in the hardware multiplication unit to meet the real-time requirements of high frame rate display; in addition, the compensation can be performed in segments, for example, the compensation coefficient can be gradually reduced when the brightness value exceeds a certain threshold to avoid excessive backlight power consumption or local overexposure.

[0101] refer to Figure 10 As shown, the control module determines the compensated subfield brightness value based on the subfield brightness value and a third lookup table, and generates a backlight drive signal based on the compensated subfield brightness value. The third lookup table stores a third mapping relationship between subfield brightness values ​​and compensated subfield brightness values. The third mapping relationship is to compensate the subfield brightness value by calculating the product of the subfield brightness value and a compensation coefficient. The compensation coefficient is the ratio of the maximum grayscale value of the pixel in the target grayscale mode to the effective grayscale value.

[0102] The above embodiments implement backlight compensation calculations using a lookup table, avoiding the latency caused by real-time multiplication. The third lookup table can be stored in non-volatile memory and dynamically updated when switching display modes (such as HDR, SDR). The third lookup table is generated during the system's factory or calibration phase. For each possible subfield brightness value L_sub, its relationship with the compensation coefficient K_comp (K_comp = G_max / (DR...)) is calculated. useThe product of -1) is L_comp = L_sub × K_comp, and L_comp and the corresponding L_sub are stored as mapping pairs in the table. During operation, the control module reads the current subfield brightness value, directly indexes the third lookup table to obtain the compensated brightness value L_comp, and then generates a backlight drive signal based on L_comp and outputs it to the backlight drive circuit, thereby realizing brightness restoration and compensation in the backlight layer.

[0103] The lookup table method pre-compiles the compensation calculations, eliminating the need for real-time multiplication during operation. This results in high real-time performance, low latency, and suitability for high frame rate video displays. Backlight compensation restores peak brightness levels, maintaining image contrast. The compensation applies to the backlight without altering the pixel drive signal, thus avoiding the risks of color shift and non-linear distortion on the pixel side.

[0104] Furthermore, this application also discloses a driving method for a display device, which is executed by a control module, referencing... Figure 11 As shown, the method includes the following steps: Step S111: The control module analyzes the frame images in the received video signal to obtain subfield pixel data and subfield backlight data; Step S112: Based on the subfield backlight data corresponding to the frame image, generate a backlight driving signal and send it to the backlight driving circuit; Step S113: Map the initial grayscale value of the first pixel of the subfield pixel data to the target grayscale value in the target grayscale mode, wherein the initial grayscale value is the grayscale value in the first grayscale mode, the maximum grayscale value of the first grayscale mode is 255, the maximum grayscale value in the target grayscale mode is N times 255, and one pixel on the display panel includes N sub-pixels. Step S114: Determine the sub-grayscale values ​​of N sub-pixels corresponding to the first pixel based on the target grayscale value of the first pixel, wherein the sum of the sub-grayscale values ​​of the N sub-pixels is equal to the target grayscale value of the first pixel. Step S115: Generate a liquid crystal driving signal based on the N sub-grayscale values.

[0105] It should be noted that steps S112 and S113~S115 can be executed in parallel.

[0106] The specific implementation methods of each of the above steps are the same as those in the above embodiments, and will not be repeated here.

[0107] The driving method in this embodiment extracts sub-field pixel data and sub-field backlight data from the frame image through steps S113-S115. The control module maps the initial grayscale value to the target grayscale value. The target grayscale value has higher accuracy than existing conventional grayscale values, and the equivalent bit depth is... With the increase in N=3, the equivalent bit depth is 9.58, meaning that the display device of this application can display an equivalent bit depth greater than 8 bits, which significantly improves the image detail reproduction and brightness control accuracy of the display device.

[0108] 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.

[0109] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the described embodiments and various different variations of embodiments suitable for specific use considerations.

Claims

1. A display device, characterized in that, include: The display module includes a timing controller and a display panel that are electrically connected; A backlight module includes an electrically connected backlight driving circuit and a light-emitting unit, wherein the backlight driving circuit is used to drive the light-emitting unit to emit light; The control module is electrically connected to the backlight module and the display panel; The control module is configured as follows: The frame images in the received video signal are analyzed to obtain subfield pixel data and subfield backlight data; Based on the subfield backlight data corresponding to the frame image, a backlight driving signal is generated and sent to the backlight driving circuit. The initial grayscale value of the first pixel of the subfield pixel data is mapped to the target grayscale value in the target grayscale mode, wherein the initial grayscale value is the grayscale value in the first grayscale mode, the maximum grayscale value in the target grayscale mode is N times 255, and one pixel on the display panel includes N sub-pixels. The sub-grayscale values ​​of N sub-pixels corresponding to the first pixel are determined based on the target grayscale value of the first pixel, wherein the sum of the sub-grayscale values ​​of the N sub-pixels is equal to the target grayscale value of the first pixel. The liquid crystal driving signal is generated based on the N sub-grayscale values ​​and sent to the timing controller; The timing controller is used to generate a timing signal based on the received liquid crystal driving signal and send it to the display panel. The display panel is used to adjust the driving voltage of N sub-pixels corresponding to the first pixel point according to the timing signal and display the frame image.

2. The display device according to claim 1, characterized in that, The step of mapping the initial grayscale value of the first pixel of the subfield pixel data to the target grayscale value in the target grayscale mode includes: Based on the first conversion coefficient from the first grayscale mode to the target grayscale mode, the product of the first conversion coefficient and the initial grayscale value is calculated to determine the target grayscale value under the target grayscale mode; Wherein, the first conversion coefficient is the ratio of the maximum gray level value of the target gray level mode to the maximum gray level value of the first gray level mode.

3. The display device according to claim 1, characterized in that, The control module pre-stores the effective grayscale values ​​of the pixels of the display panel in the target grayscale mode. The step of mapping the initial grayscale value of the first pixel of the subfield pixel data to the target grayscale value in the target grayscale mode includes: Based on the second conversion coefficient from the first grayscale mode to the target grayscale mode, the product of the second conversion coefficient and the initial grayscale value is calculated to determine the target grayscale value under the target grayscale mode; Wherein, the effective grayscale value is lower than the maximum grayscale value of the target grayscale mode and higher than the maximum grayscale value of the first grayscale mode, and the second conversion coefficient is the ratio of the effective grayscale value of the target grayscale mode to the maximum grayscale value of the first grayscale mode.

4. The display device according to claim 2 or 3, characterized in that, Determining the N sub-grayscale values ​​corresponding to the first pixel based on the target grayscale value of the first pixel includes: The mean of the target grayscale value is calculated based on the number of sub-pixels N, and then rounded down to obtain a base value. This base value is then distributed to each sub-pixel. The target grayscale value is moduloed based on the number of sub-pixels to obtain the remainder. The remainder is then allocated to at least one sub-pixel, and the allocated sub-grayscale value is output.

5. The display device according to claim 2 or 3, characterized in that, The control module is configured to include: The target grayscale value is determined based on a first lookup table, which contains N sub-grayscale values. The first lookup table stores a first mapping relationship between a target grayscale value and its corresponding sub-grayscale values. The sum of the sub-grayscale values ​​is the target grayscale value, and the difference between any two sub-grayscale values ​​is an integer not exceeding 1.

6. The display device according to claim 5, characterized in that, The control module is configured to include: The expected values ​​of N sub-grayscale values ​​are determined based on a second lookup table, and the liquid crystal driving signal is generated based on the expected values ​​of the N sub-grayscale values ​​and sent to the timing controller. The second lookup table stores a second mapping relationship between N sub-grayscale values ​​and their corresponding expected values.

7. The display device according to claim 6, characterized in that, The control module is configured to include: Determine whether the first horizontal gradient and the second horizontal gradient of the first pixel and its left and right adjacent pixels have the same direction and whether the difference between them is less than a gradient threshold. If so, the second mapping relationship is: the expected values ​​corresponding to the N sub-grayscale values ​​conform to a linear relationship, which is determined based on the grayscale values ​​of the left adjacent pixel and the grayscale values ​​of the right adjacent pixel; Otherwise, the second mapping relationship is: the N sub-grayscale values ​​conform to the distribution of a non-linear curve, which is determined based on the grayscale values ​​of the left adjacent pixel and the right adjacent pixel.

8. The display device according to claim 3, characterized in that, The control module pre-stores a compensation coefficient, and the generation of the backlight driving signal based on the sub-field backlight data corresponding to the frame image specifically includes: The subfield brightness value is determined based on the subfield backlight data, the subfield brightness value is compensated by calculating the product of the subfield brightness value and the compensation coefficient, and the compensated backlight driving signal is output based on the compensated subfield brightness value. The compensation coefficient is the ratio of the maximum grayscale value of the pixel in the target grayscale mode to the effective grayscale value.

9. The display device according to claim 3, characterized in that, The control module determines the compensated subfield brightness value based on the subfield brightness value and a third lookup table, and generates a backlight drive signal based on the compensated subfield brightness value. The third lookup table stores a third mapping relationship between subfield brightness values ​​and compensated subfield brightness values. The third mapping relationship is to compensate the subfield brightness value by calculating the product of the subfield brightness value and a compensation coefficient. The compensation coefficient is the ratio of the maximum grayscale value of the pixel in the target grayscale mode to the effective grayscale value.

10. A driving method for a display device, characterized in that, include: The control module analyzes the frame images in the received video signal to obtain subfield pixel data and subfield backlight data; Based on the subfield backlight data corresponding to the frame image, a backlight driving signal is generated and sent to the backlight driving circuit. The initial grayscale value of the first pixel of the subfield pixel data is mapped to the target grayscale value in the target grayscale mode, wherein the initial grayscale value is the grayscale value in the first grayscale mode, the maximum grayscale value in the target grayscale mode is N times 255, and one pixel on the display panel includes N sub-pixels. The sub-grayscale values ​​of N sub-pixels corresponding to the first pixel are determined based on the target grayscale value of the first pixel, wherein the sum of the sub-grayscale values ​​of the N sub-pixels is equal to the target grayscale value of the first pixel. The liquid crystal driving signal is generated based on the N sub-grayscale values ​​and sent to the timing controller.

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