Display device and driving method thereof

Abstract

The application provides a display device and a driving method thereof. The driving method comprises the following steps: 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; updating a color coordinate accuracy lookup table of a predetermined target gray scale when the current driving frequency is lower than a preset threshold; and adjusting the brightness of the display device according to the updated color coordinate accuracy lookup table. The application can greatly reduce the storage space requirement of the compensation data in the timing controller by selectively updating the color coordinate accuracy lookup table, and ensure the smoothness of the brightness adjustment by updating the adjacent gray scale data in a gradient manner. In addition, the application does not require additional hardware support, thereby effectively reducing the cost. Experimental results show that the application can significantly improve the variable refresh rate performance, effectively reduce the brightness flicker, and improve the display quality.

Description

TECHNICAL FIELD

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

[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 the LCD panel, the change of the driving frequency will cause the change of the brightness. When the frequency changes suddenly, if the brightness changes too much, the human eye will perceive the flicker phenomenon, affecting the viewing experience.

[0003] In order to solve this problem, the industry has proposed a variety of brightness compensation schemes. These schemes usually need to store a large amount of compensation data to adapt to the brightness change under different refresh rates. For example, for a typical LCD panel, it may need to store 256 x 3 x 10 = 7680 bits of data for brightness compensation for each refresh rate. Considering that the VRR technology needs to support multiple refresh rates, the storage space requirement for storing compensation data in the timing controller will further increase.

[0004] This large storage space requirement will bring great pressure to 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 not only increases the manufacturing cost of the timing controller, but also may cause 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 the 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 problem faced by the current VRR technology. SUMMARY

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

[0008] The embodiment of the present application provides a driving method of 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 according to the high level duration; updating a color coordinate accuracy lookup table of a predetermined target gray scale when the current driving frequency is lower than a preset threshold; and adjusting brightness of the display device according to the updated color coordinate accuracy lookup table.

[0009] In the above driving method, the step of calculating the current driving frequency of the display device according to the high level duration comprises: calculating a product of a preset highest driving frequency and a ratio of the high level duration under the preset highest driving frequency and the measured high level duration, to obtain the current driving frequency.

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

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

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

[0013] In the above driving method, 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 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 on a driving signal of the display device.

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

[0015] In the driving method, the luminance compensation amount is inversely proportional to the current driving frequency.

[0016] Embodiments of the present application also provide a display device, comprising: a display panel; and a timing controller electrically connected to the display panel, the timing controller comprising: a storage module configured to store a color coordinate accuracy lookup table; a frequency detection module configured to measure a high-level duration of a frame start signal of the display panel; a frequency calculation module configured to calculate a current driving frequency of the display panel according to the high-level duration; a lookup table updating module configured to update color coordinate accuracy data of a predetermined target gray scale when the current driving frequency is lower than a preset threshold; and a luminance adjustment module configured to adjust luminance of the display device according to the updated color coordinate accuracy lookup table.

[0017] In the display device, the frequency calculation module is further configured to calculate a product of a preset highest driving frequency and a ratio of a high-level duration of the frame start signal under the preset highest driving frequency to the measured high-level duration, to obtain the current driving frequency.

[0018] In the display device, the lookup table updating module is further configured to read a color coordinate accuracy lookup table corresponding to the current driving frequency from the storage module, and update color coordinate accuracy data of the predetermined target gray scale based on the read color coordinate accuracy lookup table.

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

[0020] In the display device, the lookup table updating module is further configured to calculate a difference between color coordinate accuracy data of the predetermined target gray scale and adjacent gray scales, and perform linear interpolation calculation and update on color coordinate accuracy data of the adjacent gray scales based on the difference.

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

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

[0023] In the display device, the luminance compensation amount is inversely proportional to the current driving frequency.

[0024] The technical scheme of selectively updating the color coordinate standard accuracy lookup table is adopted in the application, and the color coordinate standard accuracy data of the predetermined target gray scale is updated only when the current driving frequency is lower than the preset threshold, so that the storage space requirement of the timing controller for storing the color coordinate standard accuracy lookup table is greatly reduced. In particular, in the case of only updating the color coordinate standard accuracy data of 64 gray scales and 127 gray scales in actual application, the storage space requirement of the timing controller for storing the color coordinate standard accuracy lookup table can be reduced by more than 254 times, and the problem of large storage space requirement of the timing controller in the prior art is effectively solved.

[0025] In addition, the current driving frequency is calculated by measuring the high level duration of the frame start signal in the application, 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 at the same time ensures the accuracy of frequency detection. Compared with the traditional method which needs additional timers or microcontrollers, the technical scheme of the application can realize frequency detection without increasing hardware cost, thereby solving the problem of high hardware cost for realizing frequency detection in the prior art. BRIEF DESCRIPTION OF DRAWINGS

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

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

[0028] Figure 3 is a schematic diagram of the effect comparison between the display device and the driving method thereof provided by an embodiment of the application and the prior art. DETAILED DESCRIPTION

[0029] The specific embodiments of the application will be described in detail below with reference to the accompanying drawings.

[0030] The terms "first", "second", and similar words do not represent any order, number, or importance, but are only used to distinguish different technical features. The term "multiple" and similar words represent two or more, unless otherwise explicitly limited.

[0031] Embodiments of the application can be combined with each other.

[0032] As Figure 1As shown, the display device provided by 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, which can be integrated into the same chip as 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, and the like, 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, a counter substrate, and a liquid crystal material arranged between the thin film transistor array substrate and the counter substrate, the thin film transistor array substrate includes a substrate, a gate driving circuit GOA, a pixel unit P, a scan line (GL1-GLn), a data line (DL1-DLm), a color resistance, and the like, the pixel unit P includes a thin film transistor, a pixel electrode, and the like, and 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, and the gate driving unit is configured to provide a scan signal to the pixel unit P.

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

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

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

[0038] The embodiment of the present application provides a display device, including a display panel and a timing controller TCON, the timing controller TCON is electrically connected to the display panel, and the timing controller TCON includes:

[0039] A storage module is configured to store a color coordinate accuracy lookup table.

[0040] A frequency detection module is configured to measure a high-level duration of a frame start signal of the display panel.

[0041] a frequency calculation module configured to calculate a current driving frequency of the display panel according to the high-level duration;

[0042] 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 value; and

[0043] a brightness adjustment module configured to adjust brightness of the display device according to the updated color coordinate accuracy lookup table.

[0044] The predetermined target gray scales include 64 gray scales and 127 gray scales. The preset threshold value is 50 Hz.

[0045] When updating the color coordinate accuracy lookup table, the lookup table updating module first reads a 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 72 Hz and the storage module stores lookup tables of 60 Hz and 90 Hz, the lookup table of 90 Hz is read. Then, based on the read lookup table, interpolation calculation is performed on the color coordinate accuracy data of the predetermined target gray scales (such as 64 gray scales and 127 gray scales) to obtain updated data suitable for the current driving frequency. In this way, the storage space requirement can be greatly reduced while ensuring compensation accuracy.

[0046] The lookup table updating module updates the color coordinate accuracy lookup table in a segmented manner. Specifically, the color coordinate accuracy lookup table is divided into multiple segments, and each segment corresponds to a frequency range. For example, the frequency range is divided into segments of 30-60 Hz, 60-90 Hz, 90-120 Hz, etc. When it is detected that the current driving frequency falls within a certain range, only the segment corresponding to the range is updated. This method can further reduce the storage space requirement and improve the updating efficiency.

[0047] The frequency calculation module is further configured to calculate a product of a preset highest driving frequency, a ratio of a high-level duration of a frame start signal at the preset highest driving frequency to the measured high-level duration, and the measured high-level duration, to obtain the current driving frequency.

[0048] The frequency calculation module calculates the current driving frequency in the following manner: first, a highest driving frequency is preset, for example, 144 Hz, and the duration of the high-level of the frame start signal at the highest driving frequency is measured and recorded as T_max. Then, the duration of the high-level of the current frame start signal is measured and recorded as T_current. Finally, the current driving frequency is calculated by the formula: current driving frequency = 144 Hz*(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.

[0049] Of course, the frequency calculation module can also use a lookup table method to calculate the current drive frequency. Specifically, a table of correspondence between the duration of the high level and the drive frequency is established in advance and stored in the storage module. When the duration of the high level of the current frame start signal is measured, the frequency calculation module directly looks up the table to obtain the closest drive 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.

[0050] The lookup table updating module is also configured to read, when the current drive frequency is lower than a preset threshold, a color coordinate accuracy lookup table corresponding to the current drive frequency from the storage module, and update the color coordinate accuracy data of the predetermined target gray scale based on the read color coordinate accuracy lookup table.

[0051] The lookup table updating module is also configured to perform gradient updating on the color coordinate accuracy data of the gray scales adjacent to the predetermined target gray scale.

[0052] To ensure the smoothness of brightness adjustment, the lookup table updating module not only updates the color coordinate accuracy data of the predetermined target gray scale, but also performs gradient updating on the adjacent gray scales. Specifically, the lookup table updating module selects 5 gray scales above and below the target gray scale for updating. For example, if the target gray scale is 64, the updating range is 59-69 gray scales. This gradient updating technical solution can effectively avoid unnatural phenomena caused by local brightness adjustment.

[0053] To achieve more fine gradient updating, the lookup table updating module uses a nonlinear gradient updating method. Specifically, a Gaussian function is used to determine the updating weight of the adjacent gray scales. For example, if the target gray scale is 64, the formula: weight = exp(-(x-64)^2 / (2*σ^2)) is used to calculate the updating weight of the adjacent gray scales, where x is the adjacent gray scale value and σ is an adjustable parameter. This method can achieve a more natural brightness transition.

[0054] The lookup table updating module is also configured to calculate the difference in color coordinate accuracy data between the predetermined target gray scale and its adjacent gray scales, and perform linear interpolation calculation and updating on the color coordinate accuracy data of the adjacent gray scales based on the difference.

[0055] When performing gradient updating, the lookup table updating module first calculates the difference in color coordinate accuracy data between the predetermined target gray scale and its adjacent gray scales. For example, the data difference between 64 gray scale and 63 gray scale, 65 gray scale is calculated. Then, based on these differences, the linear interpolation method is used to calculate the new data of the adjacent gray scales. Specifically, the formula: new data = original data + (difference * weight factor) is used, where the weight factor decreases with the increase of the distance from the target gray scale. This method can ensure the continuity and naturalness of brightness adjustment.

[0056] The look-up table updating module employs an adaptive interpolation method to update the color coordinate accuracy data of adjacent gray scales. Specifically, different interpolation methods are dynamically selected according to the size of the data difference between adjacent gray scales. 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 interpolation accuracy while ensuring update efficiency, especially in areas with dramatic changes in brightness.

[0057] 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 look-up table, and to convert the brightness compensation value into a compensation signal and superimpose the compensation signal on the driving signal of the display device.

[0058] 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 look-up table. Then, these compensation values are converted into analog voltage signals as compensation signals. Finally, the compensation signals are superimposed on the original display driving signals to obtain the final driving signals. This method can achieve accurate pixel-level brightness compensation and effectively improve display quality.

[0059] The brightness adjustment module employs a block processing method to improve efficiency. Specifically, the display image is divided into multiple blocks, and the brightness compensation value is calculated for each block separately. For example, the image is divided into 16x16 blocks. Then, the compensation value is calculated for the center pixel of each block, and the value is applied to the entire block. This method can significantly reduce the amount of calculation while maintaining good compensation effect.

[0060] The look-up table updating module is also used to calculate the brightness compensation amount of the predetermined target gray scale based on the current driving frequency, and to update the color coordinate accuracy data of the predetermined target gray scale based on the brightness compensation amount.

[0061] When updating the color coordinate accuracy data, the look-up table updating module first calculates the brightness compensation amount of the predetermined target gray scale based on the current driving frequency. For example, the formula: compensation amount = reference compensation amount * (reference frequency / current frequency)^n is used, where n is an adjustable parameter used to control the compensation intensity. Then, the calculated compensation amount is applied to the color coordinate accuracy data of the target gray scale to achieve accurate brightness compensation.

[0062] The brightness compensation amount is inversely proportional to the current driving frequency, because the brightness of the display panel generally increases with the decrease of the driving frequency. Specifically, a reference frequency (e.g. 60Hz) and the 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 can be 2 times the reference compensation amount. This technical solution can ensure accurate brightness compensation at different driving frequencies.

[0063] The inverse relationship between the brightness compensation amount and the current driving frequency can be implemented by a piecewise function to adapt to the characteristics of different frequency ranges. For example, define:

[0064] When the frequency f≤60Hz, the compensation amount=k1*(60 / f)

[0065] When 60Hz<f≤90Hz, the compensation amount=k2*(90 / f)

[0066] When f>90Hz, the compensation amount=k3*(120 / f)

[0067] Where k1, k2, k3 are adjustable parameters. This technical solution can more accurately control the compensation effect in different frequency ranges.

[0068] The lookup table updating module is also used to perform the operation of updating the color coordinate accuracy lookup table of the predetermined target gray scale during the vertical blanking period of a frame.

[0069] The lookup table updating module performs the updating 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 image. Selecting this time period for updating can avoid interference with the normal display process while ensuring the real-time response capability of the display device. Specifically, the updating operation is triggered at the beginning of the vertical blanking period and completed before the end of the vertical blanking period.

[0070] The lookup table updating module implements the function of dynamically adjusting the updating time. In addition to performing the updating operation during the vertical blanking period, the updating operation is also performed during other idle time periods according to the load condition of the display device. For example, when it is detected that the content of several consecutive frames changes little, the updating operation is performed during this time period. This dynamic adjustment technical solution can better balance the resources of the display device and improve the overall efficiency.

[0071] The lookup table updating module is also used to maintain the original color coordinate accuracy lookup table unchanged when the current driving frequency is higher than or equal to a preset threshold.

[0072] To further optimize the performance of the display device, the lookup table updating 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 the luminance change is usually not obvious at a higher frequency, and no compensation is needed. The preset threshold can be set according to the specific display panel characteristics, for example, set to 90Hz. This technical solution can reduce unnecessary calculation and updating operations and improve efficiency.

[0073] As an improvement, when the driving frequency is detected to change from below the preset threshold to higher than or equal to the preset threshold, the lookup table updating module does not immediately stop updating, but gradually reduces the updating frequency and the updating range. For example, the number of gray scales updated is gradually reduced in the next few frames until the updating is completely stopped. This gradual updating method can avoid the picture jump that may be caused by sudden stopping of updating.

[0074] As an improvement, the lookup table updating module has a three-level storage structure of cache, medium cache, and low cache. The cache stores complete color coordinate accuracy data of several frequency points recently used; the medium cache stores key gray scale data of a larger frequency range; and the low 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.

[0075] As an improvement, the lookup table updating module dynamically adjusts the updating frequency and the updating range according to the change speed and amplitude of the current driving frequency. For example, when the frequency changes drastically, the updating frequency is increased and the gray scale range of updating is expanded; when the frequency changes slowly, the updating frequency is reduced and the updating range is reduced. This adaptive updating technical solution can further optimize the performance and power consumption of the display device while ensuring the compensation effect.

[0076] Embodiments of the present application also provide a driving method of a display device, comprising:

[0077] Measuring the high-level duration of the frame start signal of the display device;

[0078] Calculating the current driving frequency of the display device according to the high-level duration;

[0079] When the current driving frequency is lower than the preset threshold, updating the color coordinate accuracy lookup table of the predetermined target gray scale;

[0080] Adjusting the luminance of the display device according to the updated color coordinate accuracy lookup table.

[0081] The predetermined target gray scale includes 64 gray scales and 127 gray scales. The preset threshold is 50Hz.

[0082] The look-up table updating module first reads the pre-stored color coordinate accuracy look-up table closest to the current driving frequency from the storage module when updating the color coordinate accuracy look-up table. For example, if the current driving frequency is 72 Hz and the storage module stores the look-up tables of 60 Hz and 90 Hz, the look-up table of 90 Hz is read. Then, the color coordinate accuracy data of the predetermined target gray scale (such as 64 gray scale and 127 gray scale) are calculated by interpolation based on the read look-up table to obtain the updated data suitable for the current driving frequency. In this way, the storage space requirement can be greatly reduced while ensuring the compensation accuracy.

[0083] The look-up table updating module adopts a segmented updating method to update the color coordinate accuracy look-up table. Specifically, the color coordinate accuracy look-up table is divided into multiple segments, and each segment corresponds to a frequency range. For example, the frequency range is divided into 30-60 Hz, 60-90 Hz, 90-120 Hz, etc. When it is detected that the current driving frequency falls within a certain range, only the segment corresponding to the range is updated. This method can further reduce the storage space requirement while improving the updating efficiency.

[0084] The step of calculating the current driving frequency of the display device according to the high-level duration includes:

[0085] The product of the preset maximum driving frequency and the ratio of the high-level duration of the frame start signal under the preset maximum driving frequency to the measured high-level duration is calculated to obtain the current driving frequency.

[0086] The frequency calculation module calculates the current driving frequency in the following way: first, a maximum driving frequency is preset, for example, 144 Hz, and the duration of the high-level of the frame start signal under the maximum driving frequency is measured, denoted as T_max. Then, the duration of the high-level of the current frame start signal is measured, denoted as T_current. Finally, the current driving frequency is calculated by the formula: current driving frequency = 144 Hz * (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.

[0087] Of course, the frequency calculation module can also use a look-up table method to calculate the current driving frequency. Specifically, a corresponding relationship table of high-level duration and driving frequency is pre-established and stored in the storage module. When the duration of the high-level of the current frame start signal is measured, 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.

[0088] The step of updating the color coordinate accuracy lookup table of the predetermined target gray scale when the current driving frequency is lower than the preset threshold value comprises:

[0089] When the current driving frequency is lower than the preset threshold value, the color coordinate accuracy lookup table corresponding to the current driving frequency is read from the storage module.

[0090] The color coordinate accuracy data of the predetermined target gray scale in the color coordinate accuracy lookup table is updated.

[0091] The step of updating the color coordinate accuracy lookup table of the predetermined target gray scale when the current driving frequency is lower than the preset threshold value further comprises:

[0092] The color coordinate accuracy data of the gray scales adjacent to the predetermined target gray scale is updated by gradient.

[0093] In order to ensure the smoothness of brightness adjustment, the lookup table updating module not only updates the color coordinate accuracy data of the predetermined target gray scale, but also updates its adjacent gray scales by gradient. Specifically, the lookup table updating module selects 5 gray scales above and below the target gray scale for updating. For example, if the target gray scale is 64, the updating range is 59-69 gray scales. This gradient updating technical solution can effectively avoid unnatural phenomena caused by local brightness adjustment.

[0094] In order to realize more fine gradient updating, the lookup table updating module adopts a nonlinear gradient updating method. Specifically, a Gaussian function is used to determine the updating weight of the adjacent gray scales. For example, if the target gray scale is 64, the formula: weight = exp(-(x-64)^2 / (2*σ^2)) is used to calculate the updating weight of the adjacent gray scales, where x is the value of the adjacent gray scale and σ is an adjustable parameter. This method can realize a more natural brightness transition.

[0095] The step of updating the color coordinate accuracy data of the gray scales adjacent to the predetermined target gray scale by gradient comprises:

[0096] The difference value of the color coordinate accuracy data between the predetermined target gray scale and its adjacent gray scales is calculated;

[0097] The color coordinate accuracy data of the adjacent gray scales is calculated and updated by linear interpolation based on the difference value.

[0098] When performing gradient updating, the lookup table updating module first calculates the difference value of the color coordinate accuracy data between the predetermined target gray scale and its adjacent gray scales. For example, the difference values of the data of 64 gray scale and 63 gray scale, 65 gray scale are calculated. Then, based on these difference values, the new data of the adjacent gray scales is calculated using linear interpolation method. Specifically, the formula: new data = original data + (difference value * weight factor) is used, where the weight factor decreases with the increase of the distance from the target gray scale. This method can ensure the continuity and naturalness of brightness adjustment.

[0099] The lookup table update module uses an adaptive interpolation method to update the color coordinate accuracy data of adjacent gray levels. Specifically, different interpolation methods are dynamically selected based on the magnitude of the data difference between adjacent gray levels. 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 interpolation accuracy while ensuring update efficiency, especially in areas with drastic brightness changes.

[0100] The steps for adjusting the brightness of the display device based on the updated color coordinate accuracy lookup table include:

[0101] Based on the updated color coordinate accuracy lookup table, calculate the brightness compensation value corresponding to the currently displayed content;

[0102] The brightness compensation value is converted into a compensation signal, and the compensation signal is superimposed on the drive signal of the display device.

[0103] When adjusting the brightness of the display device, the brightness adjustment module first calculates the brightness compensation value for each pixel of the currently displayed 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 signals are superimposed on the original display drive signals to obtain the final drive signal. This method can achieve pixel-level precise brightness compensation, effectively improving display quality.

[0104] The brightness adjustment module employs a block-based processing approach to improve efficiency. Specifically, the display screen is divided into multiple blocks, and a brightness compensation value is calculated for each block individually. For example, the screen can be divided into 16x16 blocks. Then, a compensation value is calculated for the center pixel of each block, and this value is applied to the entire block. This method significantly reduces computational load while maintaining good compensation results.

[0105] When the current driving frequency is lower than a preset threshold, the step of updating the color coordinate accuracy lookup table for the predetermined target grayscale also includes:

[0106] Calculate the brightness compensation amount for the predetermined target gray level based on the current driving frequency;

[0107] The color coordinate accuracy data of the predetermined target grayscale is updated based on the brightness compensation amount.

[0108] When updating color coordinate accuracy data, the lookup table update module first calculates the brightness compensation amount for the predetermined target grayscale based on the current driving frequency. For example, it uses the formula: Compensation Amount = Reference Compensation Amount * (Reference Frequency / Current Frequency)^n, where n is an adjustable parameter used to control the compensation intensity. Then, the calculated compensation amount is applied to the color coordinate accuracy data of the target grayscale to achieve precise brightness compensation.

[0109] The brightness compensation amount is inversely proportional to the current driving frequency, because the brightness of the display panel generally increases with the decrease of the driving frequency. Specifically, a reference frequency (e.g. 60Hz) and the 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 can be 2 times the reference compensation amount. This technical solution can ensure accurate brightness compensation at different driving frequencies.

[0110] The inverse relationship between the brightness compensation amount and the current driving frequency can be implemented by a piecewise function to adapt to the characteristics of different frequency ranges. For example, define:

[0111] When the frequency f≤60Hz, the compensation amount=k1*(60 / f)

[0112] When 60Hz<f≤90Hz, the compensation amount=k2*(90 / f)

[0113] When f>90Hz, the compensation amount=k3*(120 / f)

[0114] Where k1, k2, k3 are adjustable parameters. This technical solution can more accurately control the compensation effect in different frequency ranges.

[0115] In the vertical blanking period of a frame, when the current driving frequency is lower than a preset threshold, the color coordinate accuracy lookup table of the predetermined target gray scale is updated.

[0116] The lookup table update module performs the update operation in 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 image. Selecting this time period for updating can avoid interference with the normal display process, while ensuring the real-time response capability 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.

[0117] The lookup table update module realizes the function of dynamically adjusting the update timing. In addition to performing the update operation in the vertical blanking period, the update operation can also be performed in other idle time periods according to the load condition of the display device. For example, when it is detected that the content of several consecutive frames changes little, the update operation is performed in this period. This dynamic adjustment technical solution can better balance the resources of the display device and improve the overall efficiency.

[0118] The driving method further comprises:

[0119] When the current driving frequency is higher than or equal to the preset threshold, the original color coordinate accuracy lookup table is maintained unchanged.

[0120] To further optimize the performance of the display device, the lookup table updating module maintains the original color coordinate accuracy lookup table unchanged when the current driving frequency is higher than or equal to a preset threshold. This is because the luminance change is usually not significant at a higher frequency, and no compensation is needed. The preset threshold is set according to the specific display panel characteristics, for example, 90Hz. This technical solution can reduce unnecessary calculation and update operations, and improve efficiency.

[0121] As an improvement, when the lookup table updating module detects that the driving frequency changes from being lower than the preset threshold to being higher than or equal to the preset threshold, it does not stop updating immediately, but gradually reduces the update frequency and the update range. For example, the number of updated gray scales is gradually reduced over the next few frames until the update is completely stopped. This gradual update method can avoid the picture jump that may be caused by sudden stop of the update.

[0122] As an improvement, the lookup table updating module has a three-level storage structure of cache, medium cache and low cache. The cache stores the complete color coordinate accuracy data of several frequency points recently used; the medium cache stores the key gray scale data of a larger frequency range; and the low 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.

[0123] As an improvement, the lookup table updating module dynamically adjusts the update frequency and the 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 gray scale range of the update is expanded; when the frequency changes slowly, the update frequency is reduced and the update range is reduced. This adaptive update technical solution can further optimize the performance and power consumption of the display device while ensuring the compensation effect.

[0124] Figure 2 The technical solution of the present application is demonstrated in improving the average luminance stability of the display picture. In Figure 2 , the horizontal axis represents time and the vertical axis represents the luminance of the display picture.

[0125] From Figure 2 it can be seen that when the refresh rate of the display device is switched from 48Hz to 144Hz, the display device using the prior art has a significant luminance jump at the switching point. This sudden change in luminance can cause the user to perceive flicker, affecting the viewing experience.

[0126] In contrast, the display device using the technical solution of the present application has a substantially stable average luminance of the display picture when the refresh rate is switched from 48Hz to 144Hz, without a significant jump. This shows that the technical solution of the present application can effectively compensate for the luminance change caused by the change in refresh rate, thereby providing a more stable and comfortable visual experience.

[0127] Figure 3 The technical solution of the present application shows the effect of reducing the flicker degree of the picture. Figure 3 The flicker of the display device using the prior art and the technical solution of the present application is compared under L127 gray scale.

[0128] The left picture shows the flicker degree of the L127 gray scale picture of the display device using the prior art, which is -57.83 dB. The right picture shows the flicker degree of the L127 gray scale picture of the display device using the technical solution of the present application, which is reduced to -65.58 dB.

[0129] This result clearly shows that the technical solution of the present application significantly reduces the flicker degree of the picture. Compared with the prior art, the method of the present application reduces the flicker degree of L127 gray scale by about 7.75 dB. The reduction of the flicker degree means that the user perceives less brightness fluctuation when the refresh rate changes.

[0130] The technical solution of the present application selects the color coordinate standard accuracy lookup table for updating. Only when the current driving frequency is lower than the preset threshold, the color coordinate standard accuracy data of the predetermined target gray scale is updated, which greatly reduces the storage space requirement of the timing controller for storing the color coordinate standard accuracy lookup table. In particular, in the case of only updating the color coordinate standard accuracy data of 64 gray scales and 127 gray scales in actual application, the storage space requirement of the timing controller for storing the color coordinate standard accuracy lookup table 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.

[0131] In addition, the present application calculates the current driving frequency by measuring the high level duration of the frame start signal, without additional hardware support, thereby effectively reducing the hardware cost. Moreover, this method utilizes the existing frame start signal, simplifying the frequency detection process while ensuring the accuracy of frequency detection. Compared with the traditional method which requires additional timers or microcontrollers, the technical solution of the present application can realize frequency detection without increasing hardware cost, solving the problem of high hardware cost for realizing frequency detection in the prior art.

[0132] In addition, the present application updates the adjacent gray scales of the predetermined target gray scale by gradient, ensuring the smoothness of brightness adjustment and avoiding unnatural image phenomenon caused by local brightness adjustment. This method further optimizes the storage utilization rate while ensuring the compensation effect. Through the fine gradient update method, the technical solution of the present application reduces the storage space requirement of the timing controller TCON for storing the color coordinate standard accuracy lookup table while improving the compensation accuracy, solving the problem of insufficient compensation accuracy in the prior art.

[0133] In addition, the method of the present application realizes accurate brightness compensation by calculating the brightness compensation amount and applying it to the update of the color coordinate standard accuracy data. Since the brightness compensation amount is inversely proportional to the current driving frequency, adaptive brightness adjustment can be realized at different driving frequencies, and the compensation accuracy is further improved.

[0134] In addition, the method of the present application avoids interference with the normal display process by performing the lookup table update operation in the vertical blanking period of each display frame, 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 the need to store a large amount of pre-computed data.

[0135] Embodiments of the present application provide a display device driving method and a display device to solve the problem of large storage space demand for storing compensation data in the timing controller TCON in the variable refresh rate (VRR) technology.

[0136] The display device provided by the embodiments of the present application includes a display panel and a timing controller TCON. The timing controller TCON is electrically connected with 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.

[0137] The storage module is used to store a color coordinate standard accuracy lookup table. The frequency detection module is used to measure the high-level duration of a 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 standard accuracy lookup table of a 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 standard accuracy lookup table.

[0138] The display device driving method provided by the embodiments of the present application includes the following steps:

[0139] Step S1: Measure the high-level duration of a frame start signal of a display device.

[0140] 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 of gate driver on array substrate integration.

[0141] Step S2: Calculate the current driving frequency of the display device based on the high-level duration.

[0142] The frequency calculation module calculates a product of the preset maximum driving frequency and a ratio of the preset maximum driving frequency to a high level duration of the frame start signal at the preset maximum driving frequency and the measured high level duration, to obtain the current driving frequency.

[0143] For example, assuming that the preset maximum driving frequency is 144Hz, the high level duration of the STV signal at 144Hz is A, and the currently measured high level duration of the STV signal is B, the current driving frequency can be calculated by the following formula:

[0144] Current driving frequency = 144Hz * (A / B)

[0145] 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.

[0146] The lookup table updating module first determines whether the current driving frequency is lower than the preset threshold. If yes, the color coordinate accuracy lookup table corresponding to the current driving frequency is read from the storage module, and the color coordinate accuracy data of the predetermined target gray scale in the lookup table is updated.

[0147] The predetermined target gray scale can include 64 gray scales and 127 gray scales, but is not limited to these two gray scales. The preset threshold can be set to 50Hz, but can also be adjusted according to actual needs.

[0148] The updating process also includes gradient updating of the color coordinate accuracy data of the gray scales adjacent to the predetermined target gray scale. Specifically, the lookup table updating module calculates the difference of the color coordinate accuracy data between the predetermined target gray scale and its adjacent gray scales, and then performs linear interpolation calculation and updates the color coordinate accuracy data of the adjacent gray scales based on the difference.

[0149] In addition, the lookup table updating module also calculates the luminance compensation amount of the predetermined target gray scale based on the current driving frequency, and updates the color coordinate accuracy data of the predetermined target gray scale based on the luminance compensation amount. The luminance compensation amount is inversely proportional to the current driving frequency, that is, the lower the driving frequency, the greater the luminance compensation amount.

[0150] Step S4: Adjusting the luminance of the display device according to the updated color coordinate accuracy lookup table.

[0151] The luminance adjusting module calculates the luminance compensation value corresponding to the current display content based on the updated color coordinate accuracy lookup table. Then, the luminance compensation value is converted into a compensation signal, and the compensation signal is superimposed with the driving signal of the display device, so as to realize the luminance adjustment.

[0152] Table 1

[0153]

[0154] Table 1 compares the differences between the technical solution of the present application and the prior art in the frequency detection technical solution and the brightness compensation technical solution.

[0155] In terms of the frequency detection technical solution, the prior art uses a timer to measure the vertical blank time to identify the frequency. This method requires integrating a timer in the timing controller or adding a microcontroller core, resulting in cost increase. 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 the cost.

[0156] In terms of the brightness compensation technical solution, the technical solution of the present application only constructs the ACC LUT and performs brightness swap at the required gray scale and frequency. This method not only greatly reduces the storage requirement, but also maintains high adjustment accuracy, achieving good compensation effect without increasing the cost.

[0157] Table 2

[0158]

[0159] The embodiments of the present application were tested on a 16-inch wide-screen display panel with a refresh rate of 165 Hz. The test results are shown in Table 2.

[0160] Table 2 shows the test results when the frequency is switched between 48 Hz and 144 Hz at two different gray scales (L64 and L127). For the L64 gray scale, the flicker level is -54 dB without using the technical solution of the present application, and it is reduced to -65 dB after using the technical solution of the present application, which improves by 11 dB. For the L127 gray scale, the flicker level is -57 dB without using the technical solution of the present application, and it is reduced to -65 dB after using the technical solution of the present application, which improves by 8 dB. Here, dB represents the stimulation of screen flicker to the human eye.

[0161] The customer's specification requirement for the L64 gray scale is less than -55 dB, and the specification requirement for the L127 gray scale is less than -60 dB. The test results show that after using the technical solution of the present application, the flicker levels of the two gray scales are both -65 dB, and the test results of the two gray scales are both better than the specification requirement of -60 dB.

[0162] The display device driving method provided by the embodiments of the present application greatly reduces the storage space requirement of the timing controller for storing the color coordinate accuracy lookup table by selectively updating the color coordinate accuracy of the lookup table, and only updating the color coordinate accuracy data of the predetermined target gray scale when the current driving frequency is lower than the preset threshold. In particular, in the actual application, when only the color coordinate accuracy data of 64 gray scales and 127 gray scales need to be updated, the storage space requirement of the timing controller for storing the color coordinate accuracy lookup table 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.

[0163] In addition, the driving method provided by the embodiments of the present application also updates the data of adjacent gray scales by gradient, ensuring the smoothness of brightness adjustment and avoiding unnatural image phenomenon caused by local brightness adjustment.

[0164] The display device driving method provided by the embodiments of the present application can be applied to various types of liquid crystal displays, and is particularly suitable for display devices sensitive to refresh rate changes, such as game displays. For example, the method has been successfully applied to a 16-inch wide-screen 165Hz refresh rate display panel and has realized mass production.

[0165] In summary, the display device driving method and display device provided by the embodiments of the present application realize brightness compensation of variable refresh rate without increasing hardware cost through innovative frequency detection method and selective color coordinate accuracy lookup table updating method. The method not only greatly reduces the storage space requirement of the timing controller TCON for storing the color coordinate accuracy lookup table, but also ensures good compensation effect, improves the performance of the liquid crystal display and reduces the cost.

[0166] The embodiments of the present application are described in detail above, and the content of the specification should not be understood as limiting the scope of protection of the present application.

Claims

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

2. The method as described in claim 1, characterized in that, The step of calculating the current driving frequency of the display device based on the duration of the high level includes: The current driving frequency is obtained by multiplying the preset maximum driving frequency by the ratio of the frame start signal high-level duration at the preset maximum driving frequency to the measured high-level duration.

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

4. The method as described in claim 3, characterized in that, The step of updating the color coordinate accuracy lookup table of the predetermined target grayscale when the current driving frequency is lower than a preset threshold further includes: Gradient updates are performed on the color coordinate accuracy data of adjacent gray levels of the predetermined target gray level.

5. The method as described in claim 4, characterized in that, The step of performing gradient update on the color coordinate accuracy data of adjacent gray levels of the predetermined target gray level includes: Calculate the color coordinate accuracy data difference between the predetermined target grayscale and its adjacent grayscale; and Based on the difference, the color coordinate accuracy data of the adjacent gray levels are calculated and updated by linear interpolation.

6. The method as described in claim 1, characterized in that, The step of adjusting the brightness of the display device according to the updated color coordinate accuracy lookup table includes: Based on the updated color coordinate accuracy lookup table, calculate the brightness compensation value corresponding to the currently displayed content; and The brightness compensation value is converted into a compensation signal, and the compensation signal is superimposed on the driving signal of the display device.

7. The method as described in claim 1, characterized in that, The step of updating the color coordinate accuracy lookup table of the predetermined target grayscale when the current driving frequency is lower than a preset threshold further includes: Based on the current driving frequency, calculate the brightness compensation amount for the predetermined target grayscale; and The color coordinate accuracy data of the predetermined target grayscale is updated based on the brightness compensation amount.

8. The method as described in claim 7, characterized in that, The brightness compensation amount is inversely proportional to the current driving frequency.

9. A display device, characterized in that, include: Display panel; as well as A timing controller, electrically connected to the display panel, the timing controller comprising: The storage module is used to store the color coordinate accuracy lookup table; A frequency detection module is used to measure the high-level duration of the frame start signal of the display panel; A frequency calculation module is used to calculate the current driving frequency of the display panel based on the duration of the high level. The lookup table update module is used to update the 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 is used to adjust the brightness of the display device according to the updated color coordinate accuracy lookup table.

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

11. The display device as claimed in claim 9, characterized in that, 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.

12. The display device as claimed in claim 11, characterized in that, The lookup table update module is also used to perform gradient updates on the color coordinate accuracy data of gray levels adjacent to the predetermined target gray level.

13. The display device as claimed in claim 12, characterized in that, The lookup table update module is also used to calculate the difference in color coordinate accuracy data between the predetermined target gray level and its adjacent gray levels, and to perform linear interpolation calculation and update the color coordinate accuracy data of the adjacent gray levels based on the difference.

14. The display device as claimed in claim 9, characterized in that, 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 drive signal of the display device.

15. The display device as claimed in claim 9, characterized in that, The lookup table update module is also used to calculate the brightness compensation amount of the predetermined target grayscale based on the current driving frequency, and update the color coordinate accuracy data of the predetermined target grayscale based on the brightness compensation amount.

16. The display device as claimed in claim 15, characterized in that, The brightness compensation amount is inversely proportional to the current driving frequency.

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