Display device and driving method thereof

Abstract

The invention provides a display device and a driving method thereof. The driving method includes: measuring a high-level duration of a frame start signal of the display device; calculating the current driving frequency of the display device based on the high level duration; when the current driving frequency is lower than a preset threshold value, updating a color coordinate accuracy lookup table of a predetermined target gray scale; and adjusting the brightness of the display device according to the updated color coordinate accuracy lookup table. By selectively updating the color coordinate accuracy lookup table, the requirement for the storage space for storing the compensation data in the time schedule controller is greatly reduced, and meanwhile, the smoothness of brightness adjustment is ensured by updating the adjacent gray scale data in a gradient mode. In addition, additional hardware support is not needed, and the cost is effectively reduced. Experimental results show that the variable refresh rate performance can be remarkably improved, brightness flicker is effectively reduced, and the display quality is improved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display device and a driving method thereof. Background Art

[0002] Variable refresh rate (VRR) technology can dynamically adjust the driving frequency of the LCD panel according to the input image information, thereby improving the display effect and user experience. However, in LCD panels, changes in driving frequency will cause changes in brightness. When the frequency changes suddenly, if the brightness changes too much, the human eye will perceive flickering, affecting the viewing experience.

[0003] To solve this problem, the industry has proposed a variety of brightness compensation solutions. These solutions usually require the storage of a large amount of compensation data to adapt to the brightness changes at different refresh rates. For example, for a typical LCD panel, it may be necessary to store 256 x 3 x 10 = 7680 bits of data for each refresh rate for brightness compensation. Considering that VRR technology needs to support multiple refresh rates, the storage space required to store compensation data in the timing controller will further increase.

[0004] This large storage space requirement will put tremendous pressure on the timing controller (Timing Controller IC). As the core control chip of the LCD panel, the storage capacity of the timing controller directly affects the cost and performance of the entire display device. Large-capacity storage will not only increase the manufacturing cost of the timing controller, but may also lead to problems such as increased chip area and increased power consumption.

[0005] In addition, large-capacity storage may also affect the response speed of the display device. When the refresh rate changes, a large amount of compensation data needs to be quickly read and applied, which may cause a response delay of the display device and affect the user experience.

[0006] Therefore, how to effectively reduce the storage space requirement for storing compensation data in the timing controller while ensuring the brightness compensation effect has become an important technical issue facing the current VRR technology. Summary of the invention

[0007] The embodiments of the present application provide a display device and a driving method thereof, aiming to solve the technical problem that the existing timing controller for implementing brightness compensation based on VRR technology has a large storage space requirement for storing compensation data.

[0008] An embodiment of the present application provides a method for driving a display device, comprising: measuring a high-level duration of a frame start signal of the display device; calculating a current driving frequency of the display device based on the high-level duration; when the current driving frequency is lower than a preset threshold, updating a color coordinate accuracy lookup table of a predetermined target grayscale; and adjusting the brightness of the display device according to the updated color coordinate accuracy lookup table.

[0009] In the above-mentioned driving method, the step of calculating the current driving frequency of the display device based on the high-level duration includes: calculating the product of the preset highest driving frequency and the ratio of the high-level duration of the frame start signal at the preset highest driving frequency to the measured high-level duration to obtain the current driving frequency.

[0010] In the above-mentioned driving method, when the current driving frequency is lower than a preset threshold, the step of updating the color coordinate accuracy lookup table of the predetermined target grayscale includes: when the current driving frequency is lower than the preset threshold, reading a pre-stored color coordinate accuracy lookup table corresponding to the current driving frequency from a storage module; and updating the color coordinate accuracy data of the predetermined target grayscale in the color coordinate accuracy lookup table.

[0011] In the above driving method, when the current driving frequency is lower than a preset threshold, the step of updating the color coordinate accuracy lookup table of the predetermined target grayscale further comprises: gradient updating the color coordinate accuracy data of grayscales adjacent to the predetermined target grayscale.

[0012] In the above-mentioned driving method, the step of gradient updating the color coordinate accuracy data of the gray scales adjacent to the predetermined target gray scale includes: calculating the color coordinate accuracy data difference between the predetermined target gray scale and its adjacent gray scale; and performing linear interpolation calculation and updating on the color coordinate accuracy data of the adjacent gray scales based on the difference.

[0013] In the above-mentioned driving method, the step of adjusting the brightness of the display device according to the updated color coordinate accuracy lookup table includes: calculating a brightness compensation value corresponding to the current display content based on the updated color coordinate accuracy lookup table; and converting the brightness compensation value into a compensation signal, and superimposing the compensation signal with the driving signal of the display device.

[0014] In the above-mentioned driving method, when the current driving frequency is lower than a preset threshold, the step of updating the color coordinate accuracy lookup table of the predetermined target grayscale also includes: calculating the brightness compensation amount of the predetermined target grayscale based on the current driving frequency; and updating the color coordinate accuracy data of the predetermined target grayscale based on the brightness compensation amount.

[0015] In the above driving method, the brightness compensation amount is in inverse proportion to the current driving frequency.

[0016] An embodiment of the present application also provides a display device, comprising: a display panel; and a timing controller electrically connected to the display panel, the timing controller comprising: a storage module for storing a color coordinate accuracy lookup table; a frequency detection module for measuring the high-level duration of a frame start signal of the display panel; a frequency calculation module for calculating a current driving frequency of the display panel based on the high-level duration; a lookup table update module for updating a color coordinate accuracy lookup table of a predetermined target grayscale when the current driving frequency is lower than a preset threshold; and a brightness adjustment module for adjusting the brightness of the display device according to the updated color coordinate accuracy lookup table.

[0017] In the above display device, the frequency calculation module is also used to calculate the product of the preset highest driving frequency and the ratio of the high level duration of the frame start signal at the preset highest driving frequency to the measured high level duration to obtain the current driving frequency.

[0018] In the above display device, the lookup table update module is also used to read a pre-stored color coordinate accuracy lookup table corresponding to the current driving frequency from the storage module, and update the color coordinate accuracy data of the predetermined target grayscale based on the read color coordinate accuracy lookup table.

[0019] In the above display device, the lookup table updating module is further used to perform gradient updating on the color coordinate accuracy data of the gray scales adjacent to the predetermined target gray scale.

[0020] In the above display device, the lookup table updating module is further used to calculate the color coordinate accuracy data difference between the predetermined target grayscale and its adjacent grayscale, and perform linear interpolation calculation and update the color coordinate accuracy data of the adjacent grayscale based on the difference.

[0021] In the above display device, the brightness adjustment module is also used to calculate the brightness compensation value corresponding to the current display content based on the updated color coordinate accuracy lookup table, convert the brightness compensation value into a compensation signal, and superimpose the compensation signal with the driving signal of the display device.

[0022] In the above display device, the lookup table updating module is further used to calculate a brightness compensation amount of a predetermined target grayscale based on the current driving frequency, and to update the color coordinate accuracy data of the predetermined target grayscale based on the brightness compensation amount.

[0023] In the above display device, the brightness compensation amount is in inverse proportion to the current driving frequency.

[0024] The present application adopts a technical solution of selectively updating the color coordinate accuracy lookup table, and updates the color coordinate accuracy data of the predetermined target grayscale only when the current driving frequency is lower than the preset threshold, which greatly reduces the storage space requirement of the timing controller for storing the color coordinate accuracy lookup table. In particular, in actual applications, when only the color coordinate accuracy data of 64 grayscales and 127 grayscales need to be updated, the storage space requirement for storing the color coordinate accuracy lookup table in the timing controller can be reduced by more than 254 times, effectively solving the problem of large storage space requirement of the timing controller in the prior art.

[0025] In addition, the present application calculates the current driving frequency by measuring the high level duration of the frame start signal, without the need for additional hardware support, thereby effectively reducing the hardware cost. Moreover, this method utilizes the existing frame start signal, simplifies the frequency detection process, and ensures the accuracy of frequency detection. Compared with the traditional method that requires an additional timer or microcontroller, the technical solution of the present application can realize frequency detection without increasing the hardware cost, solving the problem that the prior art requires high hardware cost to realize frequency detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic diagram of a display device provided in an embodiment of the present application.

[0027] Figure 2 It is a schematic diagram of a driving method of a display device provided in an embodiment of the present application.

[0028] Figure 3 It is a schematic diagram comparing the effects of the display device and the driving method thereof provided in the embodiment of the present application with those of the prior art. DETAILED DESCRIPTION

[0029] The specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0030] The terms "first", "second" and similar words do not indicate any order, quantity or importance, but are only used to distinguish different technical features. The term "plurality" and similar words mean two or more, unless otherwise clearly defined.

[0031] The embodiments of the present application may be combined with each other.

[0032] like Figure 1As shown, the display device provided in the embodiment of the present application includes a display panel (LCD), a timing controller TCON, a source driving circuit DD, and a power management chip (not shown in the figure, the power management chip can be integrated into the same chip with the timing controller TCON). The liquid crystal display panel includes a plurality of pixel units P, a plurality of scan lines (GL1~GLn), a plurality of data lines (DL1~DLm), a gate driving circuit GOA, etc., the plurality of pixel units P are arranged in rows and columns, the gate driving circuit GOA is electrically connected to the plurality of scan lines (GL1~GLn), the source driving circuit DD is electrically connected to the plurality of data lines (DL1~DLm), the scan lines (GL1~GLn) and the data lines (DL1~DLm) are electrically connected to the pixel units P, and the timing controller TCON is electrically connected to the gate driving circuit GOA and the source driving circuit DD.

[0033] The liquid crystal display panel includes a thin film transistor array substrate, an opposing substrate and a liquid crystal material arranged between the thin film transistor array substrate and the opposing substrate. The thin film transistor array substrate includes a substrate, a gate drive circuit GOA, a pixel unit P, a scan line (GL1~GLn), a data line (DL1~DLm), a color resistor, etc. The pixel unit P includes a thin film transistor, a pixel electrode, etc. The thin film transistor is electrically connected to the pixel electrode, the scan line (GL1~GLn) and the data line (DL1~DLm).

[0034] The gate driving circuit GOA includes a plurality of cascaded gate driving units. Each gate driving unit is electrically connected to a row of pixel units P. The gate driving unit is used to provide a scanning signal to the pixel units P.

[0035] The source driving circuit DD is used to provide a data signal to the pixel unit P.

[0036] The timing controller TCON is used to receive externally input image data, and control the gate driving circuit GOA to output a scanning signal, and control the source driving circuit DD to output a data signal.

[0037] The power management chip is used to provide the required operating voltage for each part of the liquid crystal display device.

[0038] An embodiment of the present application provides a display device, including a display panel and a timing controller TCON, wherein the timing controller TCON is electrically connected to the display panel, and the timing controller TCON includes: A storage module, used for storing a color coordinate accuracy lookup table; A frequency detection module, used to measure the high level duration of the frame start signal of the display panel; A frequency calculation module, used for calculating the current driving frequency of the display panel according to the high level duration; a lookup table updating module, configured to update a color coordinate accuracy lookup table of a predetermined target gray scale when a current driving frequency is lower than a preset threshold; and The brightness adjustment module is used to adjust the brightness of the display device according to the updated color coordinate accuracy lookup table.

[0039] The predetermined target grayscales include grayscale 64 and grayscale 127. The preset threshold is 50 Hz.

[0040] When the lookup table update module updates the color coordinate accuracy lookup table, it first reads the pre-stored color coordinate accuracy lookup table closest to the current driving frequency from the storage module. For example, if the current driving frequency is 72Hz, and the storage module stores lookup tables for 60Hz and 90Hz, the 90Hz lookup table is read. Then, based on the read lookup table, the color coordinate accuracy data of the predetermined target grayscale (such as 64 grayscale and 127 grayscale) is interpolated to obtain updated data suitable for the current driving frequency. This can significantly reduce the storage space requirements while ensuring compensation accuracy.

[0041] The lookup table update module updates the color coordinate accuracy lookup table in a segmented update manner. Specifically, the color coordinate accuracy lookup table is divided into multiple segments, each of which corresponds to a frequency range. For example, the frequency range is divided into segments such as 30-60Hz, 60-90Hz, and 90-120Hz. When it is detected that the current driving frequency falls into a certain range, only the segment corresponding to the range is updated. This method can further reduce the storage space requirement while improving the update efficiency.

[0042] The frequency calculation module is also used to calculate the product of the preset highest driving frequency and the ratio of the high level duration of the frame start signal at the preset highest driving frequency to the measured high level duration to obtain the current driving frequency.

[0043] The frequency calculation module calculates the current driving frequency in the following way: First, a maximum driving frequency is preset, such as 144Hz, and the duration of the high level of the frame start signal at the maximum driving frequency is measured, recorded as T_max. Then, the duration of the high level of the current frame start signal is measured, recorded as T_current. Finally, the current driving frequency is calculated by the formula: current driving frequency = 144Hz*(T_max / T_current). This calculation method is simple and efficient, does not require additional hardware support, and can quickly and accurately obtain the current driving frequency.

[0044] Of course, the frequency calculation module can also use a lookup table method to calculate the current driving frequency. Specifically, a corresponding relationship table between the duration of a high level and the driving frequency is pre-established and stored in the storage module. After measuring the duration of the high level of the current frame start signal, the frequency calculation module directly looks up the table to obtain the closest driving frequency value. If the measured value falls between two table entries, a linear interpolation method can be used to calculate a more accurate frequency value. This method can reduce the complexity of real-time calculation and improve the speed of frequency detection.

[0045] The lookup table update module is also used to read a pre-stored color coordinate accuracy lookup table corresponding to the current driving frequency from the storage module when the current driving frequency is lower than a preset threshold, and update the color coordinate accuracy data of the predetermined target grayscale based on the read color coordinate accuracy lookup table.

[0046] The lookup table updating module is also used to perform gradient updating on the color coordinate accuracy data of the gray scales adjacent to the predetermined target gray scale.

[0047] In order to ensure the smoothness of brightness adjustment, the lookup table update module not only updates the color coordinate accuracy data of the predetermined target grayscale, but also performs gradient updates on its adjacent grayscales. Specifically, the lookup table update module selects 5 grayscales above and below the target grayscale for update. For example, if the target grayscale is 64, the update range is grayscale 59-69. This gradient update technical solution can effectively avoid the unnatural phenomenon of the image caused by local brightness adjustment.

[0048] In order to achieve more refined gradient updates, the lookup table update module adopts a nonlinear gradient update method. Specifically, a Gaussian function is used to determine the update weights of adjacent grayscales. For example, if the target grayscale is 64, the formula: weight = exp(-(x-64)^2 / (2*σ^2)) is used to calculate the update weights of adjacent grayscales, where x is the adjacent grayscale value and σ is an adjustable parameter. This method can achieve a more natural brightness transition.

[0049] The lookup table updating module is further used to calculate the color coordinate accuracy data difference between the predetermined target gray scale and its adjacent gray scale, and perform linear interpolation calculation and update the color coordinate accuracy data of the adjacent gray scale based on the difference.

[0050] When performing gradient update, the lookup table update module first calculates the color coordinate accuracy data difference between the predetermined target grayscale and its adjacent grayscale. For example, the data difference between grayscale 64 and grayscale 63 and grayscale 65 is calculated. Then, based on these differences, the new data of the adjacent grayscales is calculated using the linear interpolation method. Specifically, the formula is used: new data = original data + (difference * weight factor), where the weight factor decreases as the distance from the target grayscale increases. This method can ensure the continuity and naturalness of brightness adjustment.

[0051] The lookup table update module uses an adaptive interpolation method to update the color coordinate accuracy data of adjacent grayscales. Specifically, different interpolation methods are dynamically selected according to the size of the data difference between adjacent grayscales. For example, linear interpolation is used when the difference is small, and cubic spline interpolation is used when the difference is large. This method can improve the interpolation accuracy while ensuring the update efficiency, especially in areas with drastic brightness changes.

[0052] The brightness adjustment module is further used to calculate a brightness compensation value corresponding to the current display content based on the updated color coordinate accuracy lookup table, convert the brightness compensation value into a compensation signal, and superimpose the compensation signal with a driving signal of the display device.

[0053] When adjusting the brightness of the display device, the brightness adjustment module first calculates the brightness compensation value of each pixel of the current display content based on the updated color coordinate accuracy lookup table. Then, these compensation values ​​are converted into analog voltage signals as compensation signals. Finally, the compensation signal is superimposed with the original display drive signal to obtain the final drive signal. This method can achieve accurate brightness compensation at the pixel level and effectively improve the display quality.

[0054] The brightness adjustment module uses a block processing method to improve efficiency. Specifically, the display screen is divided into multiple blocks, and the brightness compensation value is calculated for each block separately. For example, the screen is divided into 16x16 blocks. Then, the compensation value is calculated for the central pixel of each block and applied to the entire block. This method can significantly reduce the amount of calculation while maintaining a good compensation effect.

[0055] The lookup table updating module is further used to calculate a brightness compensation amount of a predetermined target grayscale based on the current driving frequency, and to update the color coordinate accuracy data of the predetermined target grayscale based on the brightness compensation amount.

[0056] When updating the color coordinate accuracy data, the lookup table update module first calculates the brightness compensation amount of the predetermined target grayscale based on the current driving frequency. For example, the formula is used: compensation amount = reference compensation amount * (reference frequency / current frequency) ^ n, where n is an adjustable parameter for controlling the compensation intensity. Then, the calculated compensation amount is applied to the color coordinate accuracy data of the target grayscale to achieve accurate brightness compensation.

[0057] The brightness compensation amount is inversely proportional to the current driving frequency because the brightness of the display panel usually increases as the driving frequency decreases. Specifically, a reference frequency (such as 60Hz) and a corresponding reference compensation amount are set, and then the compensation amount is adjusted proportionally according to the current frequency. For example, if the current frequency is 30Hz, the compensation amount may be twice the reference compensation amount. This technical solution can ensure accurate brightness compensation at different driving frequencies.

[0058] The inverse relationship between the brightness compensation amount and the current driving frequency can be achieved through a piecewise function to adapt to the characteristics of different frequency ranges. For example, define: When the frequency f ≤ 60Hz, the compensation amount = k1*(60 / f) When 60Hz < f ≤ 90Hz, the compensation amount = k2*(90 / f) When f > 90Hz, the compensation amount = k3*(120 / f) Where k1, k2, and k3 are adjustable parameters. This technical solution can more precisely control the compensation effect in different frequency ranges.

[0059] The lookup table update module is also used to perform an operation of updating the color coordinate accuracy lookup table for a predetermined target gray level during the vertical blanking period of a frame.

[0060] The lookup table update module performs the update operation during the vertical blanking period of each frame. The vertical blanking period refers to the short blank period before the display switches to the next frame of image. Selecting this time period for update can avoid interfering with the normal display process and ensure the real-time response ability of the display device. Specifically, the update operation is triggered at the beginning of the vertical blanking period and completed before the end of the vertical blanking period.

[0061] The lookup table update module implements the function of dynamically adjusting the update timing. In addition to performing the update operation during the vertical blanking period, it also selects other idle time periods for update according to the load condition of the display device. For example, when it is detected that the content of several consecutive frames changes little, this period of time is used for the update operation. This technical solution of dynamic adjustment can better balance the resources of the display device and improve the overall efficiency.

[0062] The lookup table update module is also used to keep the original color coordinate accuracy lookup table unchanged when the current driving frequency is higher than or equal to the preset threshold.

[0063] In order to further optimize the performance of the display device, the lookup table update module maintains the original color coordinate accuracy lookup table unchanged when the current driving frequency is higher than or equal to the preset threshold. This is because at higher frequencies, the brightness change is usually not obvious and no compensation is required. The preset threshold can be set according to the specific characteristics of the display panel, for example, set to 90Hz. This technical solution can reduce unnecessary calculations and update operations and improve efficiency.

[0064] As an improvement, when the lookup table update module detects that the driving frequency changes from lower than the preset threshold to higher than or equal to the preset threshold, it does not stop updating immediately, but gradually reduces the update frequency and update range. For example, in the next few frames, the number of updated grayscales is gradually reduced until the update is completely stopped. This gradual update method can avoid the screen jump that may be caused by suddenly stopping the update.

[0065] As an improvement, the lookup table update module has a three-level storage structure of high-speed cache, medium-speed cache and low-speed cache. The high-speed cache stores the complete color coordinate accuracy data of several recently used frequency points; the medium-speed cache stores the key grayscale data of a larger frequency range; and the low-speed cache is the complete color coordinate accuracy lookup table. This multi-level cache technical solution can achieve the optimal balance between access speed and storage efficiency in different scenarios.

[0066] As an improvement, the lookup table update module dynamically adjusts the update frequency and update range according to the change speed and amplitude of the current driving frequency. For example, when the frequency changes drastically, the update frequency is increased and the updated grayscale range is expanded; when the frequency changes slowly, the update frequency is reduced and the update range is narrowed. This adaptive update technical solution can further optimize the performance and power consumption of the display device while ensuring the compensation effect.

[0067] An embodiment of the present application further provides a method for driving a display device, comprising: Measuring the high level duration of a frame start signal of a display device; Calculate the current driving frequency of the display device according to the high level duration; When the current driving frequency is lower than a preset threshold, updating a color coordinate accuracy lookup table of a predetermined target gray scale; The brightness of the display device is adjusted according to the updated color coordinate accuracy lookup table.

[0068] The predetermined target grayscales include grayscale 64 and grayscale 127. The preset threshold is 50 Hz.

[0069] When the lookup table update module updates the color coordinate accuracy lookup table, it first reads the pre-stored color coordinate accuracy lookup table closest to the current driving frequency from the storage module. For example, if the current driving frequency is 72Hz, and the storage module stores lookup tables for 60Hz and 90Hz, the 90Hz lookup table is read. Then, based on the read lookup table, the color coordinate accuracy data of the predetermined target grayscale (such as 64 grayscale and 127 grayscale) is interpolated to obtain updated data suitable for the current driving frequency. This can significantly reduce the storage space requirements while ensuring compensation accuracy.

[0070] The lookup table update module updates the color coordinate accuracy lookup table in a segmented update manner. Specifically, the color coordinate accuracy lookup table is divided into multiple segments, each of which corresponds to a frequency range. For example, the frequency range is divided into segments such as 30-60Hz, 60-90Hz, and 90-120Hz. When it is detected that the current driving frequency falls into a certain range, only the segment corresponding to the range is updated. This method can further reduce the storage space requirement while improving the update efficiency.

[0071] The step of calculating the current driving frequency of the display device according to the high level duration includes: The current driving frequency is obtained by calculating the product of the preset highest driving frequency and the ratio of the high level duration of the frame start signal at the preset highest driving frequency to the measured high level duration.

[0072] The frequency calculation module calculates the current driving frequency in the following way: First, a maximum driving frequency is preset, such as 144Hz, and the duration of the high level of the frame start signal at the maximum driving frequency is measured, recorded as T_max. Then, the duration of the high level of the current frame start signal is measured, recorded as T_current. Finally, the current driving frequency is calculated by the formula: current driving frequency = 144Hz*(T_max / T_current). This calculation method is simple and efficient, does not require additional hardware support, and can quickly and accurately obtain the current driving frequency.

[0073] Of course, the frequency calculation module can also use a lookup table method to calculate the current driving frequency. Specifically, a corresponding relationship table between the duration of a high level and the driving frequency is pre-established and stored in the storage module. After measuring the duration of the high level of the current frame start signal, the frequency calculation module directly looks up the table to obtain the closest driving frequency value. If the measured value falls between two table entries, a linear interpolation method can be used to calculate a more accurate frequency value. This method can reduce the complexity of real-time calculation and improve the speed of frequency detection.

[0074] When the current driving frequency is lower than a preset threshold, the step of updating the color coordinate accuracy lookup table of the predetermined target gray scale includes: When the current driving frequency is lower than a preset threshold, a pre-stored color coordinate accuracy lookup table corresponding to the current driving frequency is read from the storage module; The color coordinate accuracy data of the predetermined target gray scale in the color coordinate accuracy lookup table is updated.

[0075] When the current driving frequency is lower than a preset threshold, the step of updating the color coordinate accuracy lookup table of the predetermined target grayscale further includes: The color coordinate accuracy data of the gray scales adjacent to the predetermined target gray scale are gradient updated.

[0076] In order to ensure the smoothness of brightness adjustment, the lookup table update module not only updates the color coordinate accuracy data of the predetermined target grayscale, but also performs gradient updates on its adjacent grayscales. Specifically, the lookup table update module selects 5 grayscales above and below the target grayscale for update. For example, if the target grayscale is 64, the update range is grayscale 59-69. This gradient update technical solution can effectively avoid the unnatural phenomenon of the image caused by local brightness adjustment.

[0077] In order to achieve more refined gradient updates, the lookup table update module adopts a nonlinear gradient update method. Specifically, a Gaussian function is used to determine the update weights of adjacent grayscales. For example, if the target grayscale is 64, the formula: weight = exp(-(x-64)^2 / (2*σ^2)) is used to calculate the update weights of adjacent grayscales, where x is the adjacent grayscale value and σ is an adjustable parameter. This method can achieve a more natural brightness transition.

[0078] The step of gradient updating the color coordinate accuracy data of the grayscales adjacent to the predetermined target grayscale includes: Calculating the color coordinate accuracy data difference between a predetermined target grayscale and its adjacent grayscale; The color coordinate accuracy data of adjacent gray levels are linearly interpolated and updated based on the difference.

[0079] When performing gradient update, the lookup table update module first calculates the color coordinate accuracy data difference between the predetermined target grayscale and its adjacent grayscale. For example, the data difference between grayscale 64 and grayscale 63 and grayscale 65 is calculated. Then, based on these differences, the new data of the adjacent grayscales is calculated using the linear interpolation method. Specifically, the formula is used: new data = original data + (difference * weight factor), where the weight factor decreases as the distance from the target grayscale increases. This method can ensure the continuity and naturalness of brightness adjustment.

[0080] The lookup table update module uses an adaptive interpolation method to update the color coordinate accuracy data of adjacent grayscales. Specifically, different interpolation methods are dynamically selected according to the size of the data difference between adjacent grayscales. For example, linear interpolation is used when the difference is small, and cubic spline interpolation is used when the difference is large. This method can improve the interpolation accuracy while ensuring the update efficiency, especially in areas with drastic brightness changes.

[0081] The step of adjusting the brightness of the display device according to the updated color coordinate accuracy lookup table comprises: Calculating a brightness compensation value corresponding to the current display content based on the updated color coordinate accuracy lookup table; The brightness compensation value is converted into a compensation signal, and the compensation signal is superimposed on a driving signal of the display device.

[0082] When adjusting the brightness of the display device, the brightness adjustment module first calculates the brightness compensation value of each pixel of the current display content based on the updated color coordinate accuracy lookup table. Then, these compensation values ​​are converted into analog voltage signals as compensation signals. Finally, the compensation signal is superimposed with the original display drive signal to obtain the final drive signal. This method can achieve accurate brightness compensation at the pixel level and effectively improve the display quality.

[0083] The brightness adjustment module uses a block processing method to improve efficiency. Specifically, the display screen is divided into multiple blocks, and the brightness compensation value is calculated for each block separately. For example, the screen is divided into 16x16 blocks. Then, the compensation value is calculated for the central pixel of each block and applied to the entire block. This method can significantly reduce the amount of calculation while maintaining a good compensation effect.

[0084] When the current driving frequency is lower than a preset threshold, the step of updating the color coordinate accuracy lookup table of the predetermined target grayscale further includes: Based on the current driving frequency, calculating the brightness compensation amount of the predetermined target grayscale; The color coordinate accuracy data of the predetermined target gray scale is updated based on the brightness compensation amount.

[0085] When updating the color coordinate accuracy data, the lookup table update module first calculates the brightness compensation amount of the predetermined target grayscale based on the current driving frequency. For example, the formula is used: compensation amount = reference compensation amount * (reference frequency / current frequency) ^ n, where n is an adjustable parameter for controlling the compensation intensity. Then, the calculated compensation amount is applied to the color coordinate accuracy data of the target grayscale to achieve accurate brightness compensation.

[0086] The amount of brightness compensation is inversely proportional to the current driving frequency because the brightness of the display panel usually increases as the driving frequency decreases. Specifically, a reference frequency (such as 60Hz) and a corresponding reference compensation amount are set, and then the compensation amount is adjusted proportionally according to the current frequency. For example, if the current frequency is 30Hz, the compensation amount may be twice the reference compensation amount. This technical solution can ensure accurate brightness compensation at different driving frequencies.

[0087] The inverse relationship between the amount of brightness compensation and the current driving frequency can be achieved through a piecewise function to adapt to the characteristics of different frequency ranges. For example, define: When the frequency f ≤ 60Hz, the compensation amount = k1 * (60 / f) When 60Hz < f ≤ 90Hz, the compensation amount = k2 * (90 / f) When f > 90Hz, the compensation amount = k3 * (120 / f) Where k1, k2, and k3 are adjustable parameters. This technical solution can more precisely control the compensation effect in different frequency ranges.

[0088] During the vertical blanking period of a frame, when the current driving frequency is lower than the preset threshold, update the color coordinate accuracy lookup table for the predetermined target gray level.

[0089] The lookup table update module performs the update operation during the vertical blanking period of each frame. The vertical blanking period refers to the short blank period before the display switches to the next frame of image. Selecting this time period for update can avoid interfering with the normal display process and ensure the real-time response ability of the display device. Specifically, trigger the update operation at the beginning of the vertical blanking period and complete the update before the end of the vertical blanking period.

[0090] The lookup table update module realizes the function of dynamically adjusting the update timing. In addition to performing the update operation during the vertical blanking period, it can also select other idle time periods for update according to the load situation of the display device. For example, when it is detected that the content of several consecutive frames changes little, use this time for the update operation. This technical solution of dynamic adjustment can better balance the resources of the display device and improve the overall efficiency.

[0091] The driving method also includes: When the current driving frequency is higher than or equal to the preset threshold, keep the original color coordinate accuracy lookup table unchanged.

[0092] In order to further optimize the performance of the display device, the lookup table update module maintains the original color coordinate accuracy lookup table unchanged when the current driving frequency is higher than or equal to the preset threshold. This is because at higher frequencies, the brightness change is usually not obvious and no compensation is required. The preset threshold is set according to the specific display panel characteristics, for example, it is set to 90Hz. This technical solution can reduce unnecessary calculations and update operations and improve efficiency.

[0093] As an improvement, when the lookup table update module detects that the driving frequency changes from lower than the preset threshold to higher than or equal to the preset threshold, it does not stop updating immediately, but gradually reduces the update frequency and update range. For example, in the next few frames, the number of updated grayscales is gradually reduced until the update is completely stopped. This gradual update method can avoid the screen jump that may be caused by suddenly stopping the update.

[0094] As an improvement, the lookup table update module has a three-level storage structure of high-speed cache, medium-speed cache and low-speed cache. The high-speed cache stores the complete color coordinate accuracy data of several recently used frequency points; the medium-speed cache stores the key grayscale data of a larger frequency range; and the low-speed cache is the complete color coordinate accuracy lookup table. This multi-level cache technical solution can achieve the optimal balance between access speed and storage efficiency in different scenarios.

[0095] As an improvement, the lookup table update module dynamically adjusts the update frequency and update range according to the change speed and amplitude of the current driving frequency. For example, when the frequency changes drastically, the update frequency is increased and the updated grayscale range is expanded; when the frequency changes slowly, the update frequency is reduced and the update range is narrowed. This adaptive update technical solution can further optimize the performance and power consumption of the display device while ensuring the compensation effect.

[0096] Figure 2 The effect of the technical solution of the present application in improving the average brightness stability of the display screen is demonstrated. Figure 2 In the figure, the horizontal axis represents time and the vertical axis represents the brightness of the display screen.

[0097] from Figure 2 It can be seen that when the refresh rate of the display device switches from 48 Hz to 144 Hz, the display device using the prior art has a significant brightness jump at the switching point. This sudden brightness change may cause users to perceive flickering, affecting the viewing experience.

[0098] In contrast, when the refresh rate of the display device using the technical solution of the present application is switched from 48 Hz to 144 Hz, the average brightness of the display screen remains basically stable without obvious jumps. This shows that the technical solution of the present application can effectively compensate for the brightness changes caused by the change in refresh rate, thereby providing a more stable and comfortable visual experience.

[0099] Figure 3 The effect of the technical solution of the present application in reducing the degree of screen flicker is demonstrated. Figure 3 The flickering of the display device using the prior art and the technical solution of the present application at the L127 gray scale is compared.

[0100] The left figure shows a display device using the prior art, and the flicker level of its L127 grayscale image is -57.83dB. The right figure shows a display device using the technical solution of the present application, and the flicker level of its L127 grayscale image is reduced to -65.58dB.

[0101] This result clearly shows that the technical solution of the present application significantly reduces the flicker of the picture. Compared with the prior art, the method of the present application reduces the flicker of the L127 grayscale by about 7.75dB. The reduction in flicker means that when the refresh rate changes, the brightness fluctuation perceived by the user is smaller.

[0102] The present application adopts a technical solution of selectively updating the color coordinate accuracy lookup table, and updates the color coordinate accuracy data of the predetermined target grayscale only when the current driving frequency is lower than the preset threshold, which greatly reduces the storage space requirement of the timing controller for storing the color coordinate accuracy lookup table. In particular, in actual applications, when only the color coordinate accuracy data of 64 grayscales and 127 grayscales need to be updated, the storage space requirement for storing the color coordinate accuracy lookup table in the timing controller can be reduced by more than 254 times, effectively solving the problem of large storage space requirement of the timing controller in the prior art.

[0103] In addition, the present application calculates the current driving frequency by measuring the high level duration of the frame start signal, without the need for additional hardware support, thereby effectively reducing the hardware cost. Moreover, this method utilizes the existing frame start signal, simplifies the frequency detection process, and ensures the accuracy of frequency detection. Compared with the traditional method that requires an additional timer or microcontroller, the technical solution of the present application can realize frequency detection without increasing the hardware cost, solving the problem that the prior art requires high hardware cost to realize frequency detection.

[0104] In addition, the present application ensures the smoothness of brightness adjustment by performing gradient updates on the grayscales adjacent to the predetermined target grayscale, thereby avoiding the unnatural phenomenon of the image caused by local brightness adjustment. This method further optimizes the storage utilization while ensuring the compensation effect. Through the sophisticated gradient update method, the technical solution of the present application reduces the storage space requirement for storing the color coordinate accuracy lookup table in the timing controller TCON, while also improving the compensation accuracy, solving the problem of insufficient compensation accuracy in the prior art.

[0105] In addition, the method of the present application achieves accurate brightness compensation by calculating the brightness compensation amount and applying it to the update of the color coordinate accuracy data. Since the brightness compensation amount is inversely proportional to the current driving frequency, adaptive brightness adjustment can be achieved at different driving frequencies, and the compensation accuracy is further improved.

[0106] In addition, the method of the present application avoids interference with the normal display process by performing the lookup table update operation during the vertical blanking period of each display frame, thereby ensuring the real-time response capability of the display device. This technical solution not only improves efficiency, but also further reduces the demand for storage space of the timing controller TCON, because the update operation can be performed in real time during the display process without storing a large amount of pre-calculated data.

[0107] The embodiments of the present application provide a driving method of a display device and a display device, which are used to solve the problem of large storage space requirement for storing compensation data in a timing controller TCON in variable refresh rate (VRR) technology.

[0108] The display device provided by the embodiment of the present application includes a display panel and a timing controller TCON. The timing controller TCON is electrically connected to the display panel and is used to control the driving of the display panel. The timing controller TCON includes a storage module, a frequency detection module, a frequency calculation module, a lookup table update module and a brightness adjustment module.

[0109] The storage module is used to store the color coordinate accuracy lookup table. The frequency detection module is used to measure the high level duration of the frame start signal. The frequency calculation module is used to calculate the current driving frequency based on the high level duration. The lookup table update module is used to update the color coordinate accuracy lookup table of the predetermined target gray scale when the current driving frequency is lower than a preset threshold. The brightness adjustment module is used to adjust the brightness of the display device according to the updated color coordinate accuracy lookup table.

[0110] The display device driving method provided in the embodiment of the present application comprises the following steps: Step S1: measuring the high level duration of a frame start signal of a display device.

[0111] Specifically, the frequency detection module measures the high level duration of the frame start signal. The frame start signal (Start of Vertical (STV) signal) can be a signal integrated by the gate driver on the array substrate.

[0112] Step S2: Calculating the current driving frequency of the display device based on the high level duration.

[0113] The frequency calculation module calculates the product of a preset maximum driving frequency and a ratio of a high level duration of a frame start signal at the preset maximum driving frequency to a measured high level duration to obtain a current driving frequency.

[0114] For example, assuming that the preset maximum driving frequency is 144 Hz, the high level duration of the STV signal at 144 Hz is A, and the high level duration of the currently measured STV signal is B, the current driving frequency can be calculated by the following formula: Current drive frequency = 144Hz * (A / B) Step S3: when the current driving frequency is lower than the preset threshold, updating the color coordinate accuracy lookup table of the predetermined target gray scale.

[0115] The lookup table update module first determines whether the current driving frequency is lower than a preset threshold value. If yes, it reads a pre-stored color coordinate accuracy lookup table corresponding to the current driving frequency from the storage module and updates the color coordinate accuracy data of the predetermined target gray scale in the lookup table.

[0116] The predetermined target grayscale may include, but is not limited to, grayscale 64 and grayscale 127. The preset threshold may be set to 50 Hz, but may also be adjusted according to actual needs.

[0117] The updating process also includes gradient updating the color coordinate accuracy data of the grayscales adjacent to the predetermined target grayscale. Specifically, the lookup table updating module calculates the color coordinate accuracy data difference between the predetermined target grayscale and its adjacent grayscale, and then performs linear interpolation calculation and updates the color coordinate accuracy data of the adjacent grayscales based on the difference.

[0118] In addition, the lookup table update module also calculates the brightness compensation amount of the predetermined target grayscale based on the current driving frequency, and updates the color coordinate accuracy data of the predetermined target grayscale based on the brightness compensation amount. The brightness compensation amount is inversely proportional to the current driving frequency, that is, the lower the driving frequency, the greater the brightness compensation amount.

[0119] Step S4: adjusting the brightness of the display device according to the updated color coordinate accuracy lookup table.

[0120] The brightness adjustment module calculates the brightness compensation value corresponding to the current display content based on the updated color coordinate accuracy lookup table, then converts the brightness compensation value into a compensation signal, and superimposes the compensation signal with the driving signal of the display device to achieve brightness adjustment.

[0121] Table 1

[0122] Table 1 compares the differences between the technical solution of the present application and the prior art in terms of frequency detection technical solution and brightness compensation technical solution.

[0123] In terms of frequency detection technology, the prior art uses a timer to measure the vertical blanking time (VerticalBlank Time) to identify the frequency. This method requires integrating a timer in the timing controller or adding a microcontroller core, resulting in increased costs. In contrast, the technical solution of the present application determines the frequency by measuring the high level duration of the frame start signal (STV). This method does not require additional hardware, so it does not increase costs.

[0124] In terms of the brightness compensation technical solution, the technical solution of this application only constructs the ACC LUT and performs brightness switching (Swap) at the required grayscale and frequency. This method not only greatly reduces the storage requirements, but also maintains a high adjustment accuracy, achieving a good compensation effect without increasing the cost.

[0125] Table 2

[0126] The embodiments of the present application were tested on a 16-inch widescreen display panel with a refresh rate of 165 Hz. The test results are shown in Table 2.

[0127] Table 2 shows the test results when the frequency switches between 48Hz and 144Hz under two different grayscales (L64 and L127). For the L64 grayscale, when the technical solution of the present application is not adopted, the flicker level is -54dB, and after adopting the technical solution of the present application, the flicker level is reduced to -65dB, an improvement of 11dB. For the L127 grayscale, when the technical solution of the present application is not adopted, the flicker level is -57dB, and after adopting it, it is reduced to -65dB, an improvement of 8dB. Among them, dB represents the stimulation of screen flicker to the human eye.

[0128] The customer's specification requirement for the L64 grayscale is less than -55dB, and the specification requirement for the L127 grayscale is less than -60dB. The test results show that after adopting the technical solution of the present application, the flicker level of both grayscales reaches -65dB, and the test results of both grayscales are better than the specification requirement of -60dB.

[0129] The display device driving method provided by the embodiment of the present application selectively updates the color coordinate accuracy lookup table through the technical solution, and only updates the color coordinate accuracy data of the predetermined target grayscale when the current driving frequency is lower than the preset threshold, thereby greatly reducing the storage space requirement of the timing controller for storing the color coordinate accuracy lookup table. In particular, in actual applications, when only the color coordinate accuracy data of 64 grayscales and 127 grayscales need to be updated, the storage space requirement for storing the color coordinate accuracy lookup table in the timing controller can be reduced by more than 254 times, effectively solving the problem of large storage space requirement of the timing controller in the prior art.

[0130] In addition, the driving method provided in the embodiment of the present application also updates the data of adjacent grayscales by gradient, thereby ensuring the smoothness of brightness adjustment and avoiding unnatural image phenomena caused by local brightness adjustment.

[0131] The display device driving method provided in the embodiments of the present application can be applied to various types of liquid crystal displays, and is particularly suitable for display devices that are sensitive to refresh rate changes, such as gaming monitors. For example, the method has been successfully applied to a 16-inch widescreen display panel with a refresh rate of 165Hz, and has been mass-produced.

[0132] In summary, the display device driving method and display device provided by the embodiment of the present application realize brightness compensation with variable refresh rate without increasing hardware cost through innovative frequency detection method and selective color coordinate accuracy lookup table update method. This method not only greatly reduces the storage space requirement for storing the color coordinate accuracy lookup table in the timing controller TCON, but also ensures a good compensation effect, improves the performance of the liquid crystal display and reduces the cost.

[0133] The embodiments of the present application are described in detail above, and the contents of this specification should not be construed as limiting the scope of protection of the present application.

Claims

1. A method for driving a display device, characterized in that: include: Measuring the high level duration of a frame start signal of a display device; Calculating a current driving frequency of the display device according to the high level duration; When the current driving frequency is lower than a preset threshold, updating a color coordinate accuracy lookup table of a predetermined target gray scale; as well as The brightness of the display device is adjusted according to the updated color coordinate accuracy lookup table.

2. The method according to claim 1, characterized in that The step of calculating the current driving frequency of the display device according to the high level duration comprises: The current driving frequency is obtained by calculating the product of the preset highest driving frequency and the ratio of the high level duration of the frame start signal at the preset highest driving frequency to the measured high level duration.

3. The method according to claim 1, characterized in that When the current driving frequency is lower than a preset threshold, the step of updating the color coordinate accuracy lookup table of the predetermined target grayscale comprises: When the current driving frequency is lower than a preset threshold, reading a pre-stored color coordinate accuracy lookup table corresponding to the current driving frequency from a storage module; and The color coordinate accuracy data of the predetermined target gray scale in the color coordinate accuracy lookup table is updated.

4. The method according to claim 3, characterized in that When the current driving frequency is lower than a preset threshold, the step of updating the color coordinate accuracy lookup table of the predetermined target grayscale further comprises: Gradient update is performed on the color coordinate accuracy data of the gray scales adjacent to the predetermined target gray scale.

5. The method according to claim 4, characterized in that The step of gradient updating the color coordinate accuracy data of the grayscales adjacent to the predetermined target grayscale comprises: Calculating the color coordinate accuracy data difference between the predetermined target grayscale and its adjacent grayscale; and The color coordinate accuracy data of the adjacent gray scales are linearly interpolated and updated based on the difference.

6. The method according to claim 1, wherein: The step of adjusting the brightness of the display device according to the updated color coordinate accuracy lookup table comprises: Calculating a brightness compensation value corresponding to the current display content based on the updated color coordinate accuracy lookup table; and The brightness compensation value is converted into a compensation signal, and the compensation signal is superimposed on a driving signal of the display device.

7. The method according to claim 1, characterized in that When the current driving frequency is lower than a preset threshold, the step of updating the color coordinate accuracy lookup table of the predetermined target grayscale further comprises: Based on the current driving frequency, calculating a brightness compensation amount of a predetermined target grayscale; and The color coordinate accuracy data of the predetermined target gray scale is updated based on the brightness compensation amount.

8. The method according to claim 7, characterized in that The brightness compensation amount is in inverse proportion to the current driving frequency.

9. A display device, characterized in that: include: Display panel; as well as A timing controller is electrically connected to the display panel, and the timing controller includes: A storage module, used for storing a color coordinate accuracy lookup table; A frequency detection module, used to measure the high level duration of the frame start signal of the display panel; A frequency calculation module, used for calculating the current driving frequency of the display panel according to the high level duration; a lookup table updating module, configured to update a color coordinate accuracy lookup table of a predetermined target gray scale when the current driving frequency is lower than a preset threshold; and The brightness adjustment module is used to adjust the brightness of the display device according to the updated color coordinate accuracy lookup table.

10. The display device according to claim 9, characterized in that The frequency calculation module is further used to calculate the product of the preset highest driving frequency and the ratio of the high level duration of the frame start signal at the preset highest driving frequency to the measured high level duration to obtain the current driving frequency.

11. The display device according to claim 9, wherein: The lookup table updating module is further used to read a pre-stored color coordinate accuracy lookup table corresponding to the current driving frequency from the storage module, and update the color coordinate accuracy data of the predetermined target grayscale based on the read color coordinate accuracy lookup table.

12. The display device according to claim 11, wherein: The lookup table updating module is further used to perform gradient updating on the color coordinate accuracy data of the gray scales adjacent to the predetermined target gray scale.

13. The display device according to claim 12, wherein: The lookup table updating module is further used to calculate the color coordinate accuracy data difference between the predetermined target grayscale and its adjacent grayscale, and perform linear interpolation calculation and update the color coordinate accuracy data of the adjacent grayscale based on the difference.

14. The display device according to claim 9, wherein: The brightness adjustment module is further used to calculate a brightness compensation value corresponding to the current display content based on the updated color coordinate accuracy lookup table, convert the brightness compensation value into a compensation signal, and superimpose the compensation signal with the driving signal of the display device.

15. The display device according to claim 9, wherein: The lookup table updating module is further used to calculate a brightness compensation amount of a predetermined target grayscale based on the current driving frequency, and to update the color coordinate accuracy data of the predetermined target grayscale based on the brightness compensation amount.

16. The display device according to claim 15, characterized in that The brightness compensation amount is in inverse proportion to the current driving frequency.

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