Driving method and driving apparatus of display device

Abstract

Provided are a driving method and a driving device of a display device. The method comprises: setting PWM pulse width threshold values different from each other and a PWM pulse signal width setting value for a plurality of subframes; obtaining original PWM pulse widths of the subframes by using a scattering algorithm according to original gray data of each frame of image; for each subframe whose original PWM pulse width is greater than the PWM pulse width threshold value, performing driving current and pulse width modulation, wherein the size order of the PWM pulse width threshold values determines the modulation order of the driving current of each subframe, and the modulated PWM pulse width is less than or equal to the PWM pulse width setting value of the subframe; and generating a PWM signal of the corresponding subframe according to the modulated PWM pulse width and the driving current, wherein the PWM signal is used for controlling the display of the picture on the panel. The present application solves the defect of difficulty in image gray scale refinement caused by the increase of the driving current to realize the brightness improvement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of display, and particularly relates to a driving method and a driving device of a display device. BACKGROUND

[0002] With the rapid development of LED (Light Emitting Diode) display technology, the demand for high contrast is also increasing, and 18-bit display (i.e., using 18-bit to represent the color of a single pixel) has become a universal standard. By increasing the display time, the brightness change of the pixel can be more obvious, thereby improving the contrast, but this method is limited by the refresh rate of the display, so the way of adjusting the LED driving current to improve the brightness of the LED is the current research direction in the industry.

[0003] The common method is to divide a frame into multiple subframes, and perform PWM control on each subframe, specifically: when the PWM pulse width P of the subframe reaches the PWM pulse width setting value W of the subframe (i.e., P≥W, W represents the maximum time of PWM opening in a row of display), on the basis of maintaining the PWM pulse width P=W of the subframe unchanged, the driving current of the subframe is modulated to realize display gray scale expansion, thereby obtaining higher brightness.

[0004] However, the above method also has certain problems. Assuming that the subframe number m=8 and the PWM pulse width setting value W=252 of the subframe, after using SPWM to scatter the gray data A of the image, the relationship between the gray data A of the image and the subframe number g for driving current modulation can be obtained, as shown in the following formula (1). Figure 1

[0005] In the process of implementing the above scheme, during the completion of all subframe driving current modulation, the number of subframes for implementing driving current modulation increases by 1, and the original gray A increases by 1, and this conclusion is applicable to any subframe number using the above scheme. In the image display process, the original image needs to be processed by a gamma correction curve, as shown in the following formula (2). Figure 2 As can be seen, with the increase of the original image gray, the dispersion of the gray scale data after gamma correction processing is very large, for example, the value of the original gray A of a certain frame image increases by 1, and after gamma processing, it can be directly jumped from 2000 to 2020; the value of the original gray A increases by 1 again, and after gamma processing, it can be directly jumped from 2020 to 2040. Then according to the following formula (3), the second original gray increase of 1 will cause 20 subframes to be modulated in driving current, which will cause a sharp change in brightness and color temperature. Figure 1

[0006] ​​To solve the above problems, point-by-point highlight gray scale refinement is usually performed, and the RGB components of each pixel point are refined in brightness respectively, and finally the balance on total brightness and color temperature is achieved. However, the dramatic changes in brightness and color temperature caused by current modulation of multiple sub-frames will bring great challenges to gray scale refinement, and even the balance point on total brightness and color temperature cannot be found. SUMMARY

[0007] The purpose of the embodiments of the present disclosure is to provide a driving method and a driving device of a display device, which provides a new modulation mode of driving current.

[0008] In a first aspect, the embodiments of the present disclosure provide a driving method of a display device, characterized in that the display device comprises a panel, the panel comprises a plurality of pixel units, and the display time of each frame of image on the panel is divided into a plurality of sub-frames, and the driving method comprises:

[0009] setting different PWM pulse width threshold values for the plurality of sub-frames and a PWM pulse signal width setting value, wherein the PWM pulse width threshold values of the plurality of sub-frames are all less than the PWM pulse width setting value;

[0010] obtaining the original PWM pulse width of each sub-frame by using a scattering algorithm according to the original gray scale data of each frame of image;

[0011] for each sub-frame whose original PWM pulse width is greater than the PWM pulse width threshold value, performing driving current and pulse width modulation, wherein the size order of the PWM pulse width threshold value determines the modulation order of the driving current of each sub-frame, and the modulated PWM pulse width is less than or equal to the PWM pulse width setting value of the sub-frame; and

[0012] generating a PWM signal of the corresponding sub-frame according to the modulated PWM pulse width and the driving current, and the PWM signal controls the display of the picture on the panel.

[0013] In some embodiments, the setting of different PWM pulse width threshold values for the plurality of sub-frames comprises:

[0014] setting different current modulation calibration values for the plurality of sub-frames; and

[0015] obtaining the PWM pulse width threshold value of each sub-frame according to the following equation (1);

[0016] W = V +f*g equation (1)

[0017] Wherein, W represents PWM pulse width setting value of each sub-frame, V represents PWM pulse width threshold value of each sub-frame, g is current modulation calibration value of each sub-frame, f is greater than 0, and current modulation calibration values g of the plurality of sub-frames are different from each other.

[0018] In some embodiments, the driving current modulation on the plurality of sub-frames comprises:

[0019] Setting a plurality of modulatable currents and a plurality of PWM pulse width modulation coefficients corresponding to the plurality of modulatable currents respectively;

[0020] For each sub-frame, calculating a plurality of PWM pulse width intervals according to the PWM pulse width threshold value of the sub-frame and the plurality of PWM pulse width modulation coefficients;

[0021] For each sub-frame, judging whether the original PWM pulse width of the sub-frame is in the plurality of PWM pulse width intervals, if the original PWM pulse width of the sub-frame is in a first PWM pulse width interval in the plurality of PWM pulse width intervals, taking the modulatable current corresponding to the first PWM pulse width interval as the modulated driving current of the sub-frame, if the original PWM pulse width of the sub-frame exceeds the plurality of PWM pulse width intervals, taking the maximum value of the plurality of modulatable currents as the modulated driving current of the sub-frame.

[0022] In some embodiments, the pulse width modulation on the plurality of sub-frames comprises:

[0023] For each sub-frame, judging whether the original PWM pulse width of the sub-frame is in the plurality of PWM pulse width intervals, if the original PWM pulse width of the sub-frame is in a first PWM pulse width interval in the plurality of PWM pulse width intervals, multiplying the original PWM pulse width value by the PWM pulse width modulation coefficient corresponding to the first PWM pulse width interval to obtain a PWM pulse conversion value, if the original PWM pulse width value of the sub-frame exceeds the plurality of PWM pulse width intervals, multiplying the original PWM pulse width by the PWM pulse width modulation coefficient corresponding to the maximum modulatable current to obtain a PWM pulse conversion value;

[0024] Obtaining the modulated PWM pulse width of the sub-frame based on the PWM pulse conversion value.

[0025] In some embodiments, the obtaining the final PWM pulse width value based on the PWM pulse conversion value comprises:

[0026] If the PWM pulse conversion value is greater than or equal to the PWM pulse signal width setting value, the modulated PWM pulse width of the sub-frame is equal to the PWM pulse signal width setting value; and

[0027] If the PWM pulse conversion value is less than the PWM pulse signal width setting value, the modulated PWM pulse width of the subframe is equal to the PWM pulse conversion value.

[0028] In some embodiments, the PWM pulse signal width setting value is an integer multiple of a display clock period.

[0029] In some embodiments, the modulatable currents are respectively greater than or equal to a reference current.

[0030] In some embodiments, for each subframe with an original PWM pulse width not greater than a PWM pulse width threshold value, the reference current is used as the driving current of each subframe, and the PWM pulse width of each subframe is kept unchanged.

[0031] In a second aspect, the embodiments of the present disclosure provide a driving device of a display device, comprising:

[0032] a grayscale data processing module, configured to set PWM pulse width threshold values different from each other for a plurality of subframes and a PWM pulse signal width setting value, and to obtain original PWM pulse widths of the subframes by using a scattering algorithm according to original grayscale data of each frame of image, and for each subframe with an original PWM pulse width greater than a PWM pulse width threshold value, to perform driving current and pulse width modulation, wherein the PWM pulse width threshold values of the plurality of subframes are all less than the PWM pulse width setting value, the order of magnitude of the PWM pulse width threshold values determines the modulation order of the driving currents of the subframes, and the modulated PWM pulse width is less than or equal to the PWM pulse width setting value of the subframe;

[0033] a PWM signal generation module, configured to generate a PWM signal of a corresponding subframe according to the modulated PWM pulse width and the driving current, and the PWM signal controls the display of a picture on a panel of the display device.

[0034] In some embodiments, the setting of the PWM pulse width threshold values different from each other for the plurality of subframes comprises:

[0035] setting current modulation calibration values different from each other for the plurality of subframes; and

[0036] the PWM pulse width threshold value of each subframe is obtained according to the following equation (1);

[0037] W = V +f*g equation (1)

[0038] Wherein, W represents PWM pulse width setting value of each sub-frame, V represents PWM pulse width threshold value of each sub-frame, g is current modulation calibration value of each sub-frame, f is greater than 0, and the current modulation calibration values g of the plurality of sub-frames are different from each other.

[0039] In some embodiments, the driving current modulation of the gray data processing module comprises:

[0040] Setting a plurality of modulatable currents and a plurality of PWM pulse width modulation coefficients corresponding to the plurality of modulatable currents respectively;

[0041] For each sub-frame, calculating a plurality of PWM pulse width intervals according to the PWM pulse width threshold value of the sub-frame and the plurality of PWM pulse width modulation coefficients;

[0042] For each sub-frame, judging whether the original PWM pulse width of the sub-frame is in the plurality of PWM pulse width intervals, if the original PWM pulse width of the sub-frame is in a first PWM pulse width interval in the plurality of PWM pulse width intervals, taking the modulatable current corresponding to the first PWM pulse width interval as the modulated driving current of the sub-frame, if the original PWM pulse width of the sub-frame exceeds the plurality of PWM pulse width intervals, taking the maximum value of the plurality of modulatable currents as the modulated driving current of the sub-frame.

[0043] In some embodiments, the pulse width modulation of the gray data processing module comprises:

[0044] For each sub-frame, judging whether the original PWM pulse width of the sub-frame is in the plurality of PWM pulse width intervals, if the original PWM pulse width of the sub-frame is in a first PWM pulse width interval in the plurality of PWM pulse width intervals, multiplying the original PWM pulse width value by the PWM pulse width modulation coefficient corresponding to the first PWM pulse width interval to obtain a PWM pulse conversion value, if the original PWM pulse width value of the sub-frame exceeds the plurality of PWM pulse width intervals, multiplying the original PWM pulse width by the PWM pulse width modulation coefficient corresponding to the maximum modulatable current to obtain a PWM pulse conversion value;

[0045] Obtaining the modulated PWM pulse width of the sub-frame based on the PWM pulse conversion value.

[0046] In some embodiments, the pulse width modulation of the gray data processing module further comprises:

[0047] If the PWM pulse conversion value is greater than or equal to the PWM pulse signal width setting value, the modulated PWM pulse width of the sub-frame is equal to the PWM pulse signal width setting value; and

[0048] If the PWM pulse conversion value is less than the PWM pulse signal width setting value, the modulated PWM pulse width of the subframe is equal to the PWM pulse conversion value.

[0049] In some embodiments, the modulated current is greater than or equal to the reference current.

[0050] In some embodiments, for each subframe whose original PWM pulse width is not greater than the PWM pulse width threshold value, the reference current is used as the driving current of each subframe, and the PWM pulse width of each subframe is kept unchanged.

[0051] In a third aspect, the embodiments of the present disclosure provide a computer readable storage medium, which stores a computer program. The program is executed by a processor to implement the steps of the driving method described above.

[0052] In a fourth aspect, the embodiments of the present disclosure provide a display driving chip, which comprises the driving device of the display device described above.

[0053] In a fifth aspect, the embodiments of the present disclosure provide an electronic device, which comprises the display driving chip described above.

[0054] The embodiments of the present disclosure solve the defect of difficulty in image gray scale refinement caused by the increase of driving current to achieve brightness improvement.

[0055] It should be noted that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0056] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure, taken in conjunction with the accompanying drawings, in which:

[0057] Figure 1 is a graph of the relationship between the original gray scale data A of a traditional image and the number of driving current modulation subframes g;

[0058] Figure 2 is an image data gamma correction curve;

[0059] Figure 3 is a structural schematic diagram of an LED display device;

[0060] Figure 4 is Figure 3 is a waveform diagram of a scanning signal in the LED display device in

[0061] Figure 5 is a flowchart of the driving method of the LED display device of the embodiments of the present disclosure;

[0062] Figure 6 A schematic diagram of the PWM pulse width threshold V for multiple subframes in an embodiment of this disclosure is provided;

[0063] Figure 7 Embodiments of this disclosure are given. Figure 6 A schematic diagram of the subframe current modulation sequence;

[0064] Figure 8 This is a graph showing the mapping relationship between the number of subframes g that are subjected to current modulation according to the embodiments of this disclosure and the original grayscale data A;

[0065] Figure 9a This is a mapping diagram of the PWM pulse width and PWM pulse width modulation value according to an embodiment of this disclosure;

[0066] Figure 9b This is a mapping diagram of the PWM pulse width P and the segmented drive current in an embodiment of this disclosure;

[0067] Figure 10 A flowchart is provided showing the complete calculation process of the final drive current parameter i and the final PWM pulse width P for each subframe proposed in the embodiments of this disclosure;

[0068] Figure 11 yes Figure 10 A flowchart of a specific embodiment of S15 in the diagram;

[0069] Figure 12 A schematic diagram of the PWM pulse width threshold V for multiple subframes is given as another example. Detailed Implementation

[0070] The present application will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale. Furthermore, some well-known parts may not be shown.

[0071] refer to Figure 3 The LED display device 100 includes a driving device 110, a panel 120, and a data processing device 130. On the panel 120, a plurality of pixel units Punits are arranged in a first direction (e.g., horizontal) and a second direction (e.g., vertical) to form a matrix. Each pixel unit Punit may include at least one light-emitting diode (LED), and the brightness of the pixel unit Punit is determined based on the brightness of the LED.

[0072] The drive lines DL and the scan lines SL can be arranged on the panel 120, the drive lines DL connecting one side of the pixel units Punit in the second direction, and the scan lines SL connecting the other side of the pixel units Punit in the first direction. For example, the anodes of the LEDs in the pixel units Punit are electrically connected to the drive lines DL, and the cathodes of the LEDs are electrically connected to the scan lines SL. Although Figure 3 The illustrated example is referred to as a common cathode structure (in which the cathodes of the LEDs are commonly connected), but embodiments of the present disclosure are not limited to this structure.

[0073] The selection switches SWc1 to SWcL can be arranged in each of the scan lines SL, and it is determined which scan line SL is supplied with the drive current Ie depending on whether the selection switches SWc1 to SWcL are open or closed.

[0074] Figure 4 is Figure 3 A waveform diagram of a scan signal in the LED display device in FIG. 1 is shown in FIG. 2. Referring to Figure 3 and Figure 4 One frame is divided into N (N is a natural number) sub-frames, and the scan signals Scan<1> to Scan <l>. According to the scan signals Scan<1> to Scan <l>, the driving current Ie can be sequentially supplied to the first to Lth scan lines.

[0075] The scan lines SL are connected to a low voltage portion such as a ground line in the LED display device 100. According to the present embodiment, the selection switches SWcl to SWcL can be formed on the panel 120 or on a separate substrate, or can be formed in the driving device 110.

[0076] The scan signals Scan<1> to Scan <l>It can be supplied by the drive unit 110 or by a separate control unit.

[0077] The brightness of the LEDs arranged in each pixel unit Punit can be determined based on the driving force provided within a predetermined time. The LEDs are driven by pulse width modulation (PWM), and the brightness is determined based on the on-time ratio within the PWM control time. When the LED is turned on by the driving current Ie, a positive voltage can be formed in the LED. The driving force supplied to the LED can be obtained by accumulating the product of the positive voltage and the driving current Ie over the on-time within the PWM control time, and the brightness of the LED can be determined based on the driving force. Assuming that the positive voltage and driving current Ie of the LED are fixed parameters, the driving force can be considered a value proportional to the on-time within the PWM control time. Based on this principle, the driving device 110 can control the on-time within the PWM control time, thereby controlling the brightness of the LEDs and the pixel unit Punit.

[0078] The driving device 110 may include M (M is a natural number) channel circuits connected to the driving line DL, and each channel circuit may supply driving current Ie to each pixel unit Punit.

[0079] The driving device 110 can perform PWM control on each pixel unit Punit based on the image data RGB received from the data processing device 130. The image data RGB can include the grayscale value for each pixel unit Punit. The data processing device 130 can transmit the image data RGB together with the communication clock DCLK to the driving device 110. The driving device 110 can receive the image data RGB according to the communication clock DCLK, and can obtain the grayscale value for each pixel unit Punit from the image data RGB.

[0080] The drive device 110 can determine the PWM control time for each pixel unit Punit based on the grayscale value, and can perform PWM control on each pixel unit Punit.

[0081] The driving device 110 can perform PWM control on each pixel unit Punit once per frame, and as follows: Figure 4 As shown, a frame can be divided into N subframes to perform PWM control on each pixel unit Punit in each subframe. Combined with the background technique, when the scan signal Scan... <1> To Scan <l>When the pulse width (length of time of high level) P of the pulse reaches a set value W, the driving current Ie is modulated on the basis of maintaining the pulse width P=W unchanged.

[0082] To solve the defect of image gray scale refinement difficulty brought by the above solution, the embodiment of the present disclosure proposes a driving method of a display device. The method comprises the following steps as shown in the figure. Figure 5

[0083] In step S410, the original PWM pulse width of each sub-frame is obtained by using a scattering algorithm according to the original gray scale data of each frame of image.

[0084] In step S420, different PWM pulse width threshold values are set for the plurality of sub-frames, wherein the PWM pulse width threshold values of the plurality of sub-frames are all less than the PWM pulse width set value.

[0085] In step S430, for each sub-frame whose original PWM pulse width is greater than the PWM pulse width threshold value, the driving current and the pulse width are modulated. The size order of the PWM pulse width threshold value determines the modulation order of the driving current of each sub-frame.

[0086] In step S440, the PWM signal of the corresponding sub-frame is generated according to the modulated PWM pulse width and the driving current, and the PWM signal controls the picture display on the panel.

[0087] ​Specifically, the display time of each frame of image is divided into a plurality of subframes according to actual requirements, the original gray data of each frame of image is scattered into the plurality of subframes according to a predetermined rule, and the original PWM pulse width P of each subframe is obtained according to the gray data obtained by each subframe. Each subframe is set with a PWM pulse width threshold V different from each other (assuming the number of subframes is m, which can be represented as threshold values V1, V2, …, Vm, and are not equal to each other), and the threshold width V meets the condition of being less than the PWM pulse width setting value W. The size relationship of the PWM pulse width threshold V between the subframes can be set according to actual requirements, and no further limitation is made on the premise that the PWM pulse width threshold V of each subframe is different from each other. Moreover, the driving current modulation and pulse width modulation are performed on each subframe with the original PWM pulse width greater than the PWM pulse width threshold. The driving current modulation can be performed according to the order of the PWM pulse width threshold from small to large, so that the subframe with smaller PWM pulse width threshold is earlier to perform the driving current modulation. The setting of the threshold width V < W can realize the current modulation when the subframe PWM pulse width P (P < W) is relatively low, so that the transition from the middle gray scale display to the high gray scale display is smoother. In addition, the optimization of the PWM pulse width threshold V different from each other can achieve the purpose of sequentially performing the driving current modulation for each subframe, which can solve the problem of simultaneously performing the driving current modulation for multiple subframes, and can effectively reduce the difficulty of image gray scale refinement. Figure 6 An example of the PWM pulse width threshold V based on the number of subframes m = 8 and the PWM pulse width setting value W = 252 of the present embodiment is given. In this example, the PWM pulse width threshold V (V1 ~ V8) of each subframe is as shown in the figure, and then the current modulation sequence of all subframes is as shown in the figure. Figure 7 The current modulation sequence of all subframes is as shown in the figure.

[0088] In some embodiments, as shown in Figure 7 After the order of performing the driving current modulation for each subframe is determined, the difference ΔV between the PWM pulse width threshold V of adjacent two current modulation subframes in the above driving current modulation sequence can be further set, for example, as shown in Figure 7 In the example shown in

[0089] ΔA = h · ΔV (h > 0) Formula (1)

[0090] Under the full scattering algorithm, the value of h is the number of subframes m, and the relationship between ΔA and ΔV under the full scattering algorithm is as shown in Figure 8 As shown in the figure, it can be seen from the figure that the above Figure 6 The step gray scale ΔA = (V5-V3)·m between the seventh current modulation subframe and the sixth current modulation subframe in the above formula, at this time, the value of the step gray scale ΔA between adjacent current modulation subframes can be adjusted by the subframe number m, and in other dispersion modes, the value of h can be adjusted according to actual needs. In the traditional scheme, the step gray scale between any two adjacent current modulation subframes is fixed as ΔA = 1, so by adjusting the step gray scale ΔA (as Figure 8 shown, after optimization of the algorithm, ΔA = ΔV·m at this time), the interval length of the original gray scale A corresponding to each segment of the driving current can be effectively expanded. It can be known from the gamma correction curve that although the image gray scale dispersion is high at a high-order gray scale, because the step gray scale ΔA between adjacent current modulation subframes can be adjusted, the probability of simultaneous implementation of current modulation by multiple subframes can be significantly reduced, and even the situation of simultaneous current modulation by multiple subframes (more than one) can be avoided. The process of color deviation optimization is delayed, and the difficulty of image gray scale refinement is significantly reduced.

[0091] In some embodiments, pulse width modulation is performed on the subframe with the PWM pulse width P greater than the PWM pulse width threshold V, specifically including the following operations. In order to display the brightness improvement, the subframe can be set with multiple segments of modulatable currents ik (k represents the kth segment of current), and correspondingly each segment of modulatable current corresponds to a PWM pulse width modulation coefficient qk (k represents the PWM pulse width modulation coefficient of the subframe using the kth segment of current). The one-to-one mapping relationship between ik and qk (k is an integer greater than 1), and the calculation formula of the PWM pulse width conversion value p after pulse width modulation and the subframe PWM pulse width P is as follows:

[0092] p = P * qk formula (2)

[0093] As shown in Figure 9a and Figure 9b , in the subframe 1, the pulse width threshold V = 244, the pulse width P = 252, the first segment of driving current i1 = I, and the second segment of driving current i2 = 2I, I represents the reference current. In the setting relationship of q1 = 1 and q2 = 0.5, the driving current modulation process diagram (as Figure 9b ) and the PWM pulse width P modulation process diagram of the subframe are shown as follows (as Figure 9a ).

[0094] The above embodiment improves the PWM pulse width modulation while performing driving current modulation, realizes dynamic adjustment of the duty cycle, improves the accuracy of image gray scale refinement, and reduces the brightness jump of the image when displaying at a high gray scale, thereby avoiding the back jump phenomenon.

[0095] In addition, for the case that the PWM pulse width P of the unsatisfied subframe is less than the pulse width threshold V, the driving current modulation and the modulation process of the PWM pulse width P are not required, the first section current (i.e., the reference current I) is selected as the driving current, and the PWM pulse width remains unchanged.

[0096] Of course, in actual image display, the change of image gray scale is arbitrary, such as when the pulse width P of different subframes changes from greater than V to less than V, the driving current is also reduced and the PWM pulse width is increased at this time. This case can also be processed according to the above embodiment, and will not affect the effect of the final image gray scale refinement.

[0097] Moreover, considering that the offset effects of different driving currents on the color coordinates are inconsistent, and the PWM pulse width has certain limitations for color coordinate calibration, finally, although the above embodiment can effectively reduce the difficulty of image gray scale refinement, multi-section driving current modulation is inevitable when the present scheme is executed, and color coordinate drift still occurs at this time, but with the help of the present algorithm, the problem of abnormal display of the image can be effectively alleviated.

[0098] Figure 10 A flowchart of the complete calculation process of the final driving current parameters i and the final PWM pulse width P of each subframe proposed by the embodiments of the present disclosure is given.

[0099] In step S10, the subframe number m and the subframe PWM pulse width setting value W are obtained. The PWM pulse signal width setting value W is an integer multiple of the display clock period.

[0100] In step S11, the initial current calibration value g of each subframe is determined. The calibration value g can be set according to the actual display requirements of the LED, and the calibration values g of each subframe are different from each other, and g is greater than or equal to zero.

[0101] In step S12, the PWM pulse width threshold V corresponding to the driving current parameter of each subframe is calculated. Specifically, the linear superposition sum of each subframe PWM pulse width threshold V and the calibration value g in step S11 is the PWM pulse signal width setting value W, i.e., W = V + f*g, where f satisfies greater than 0, and since the calibration values of each subframe are different from each other, the pulse width thresholds V of each subframe calculated are also different from each other.

[0102] In step S13, the PWM pulse width intervals corresponding to the plurality of driving current parameters of each subframe are calculated.

[0103] For example, the step S13 is explained. It is assumed that the n driving current values are i1, i2, i3, … in, and i1 < i2 < i3 < … < in, for example, i1, i2, i3, … in are integer multiples of the reference current I, and the corresponding PWM pulse width modulation coefficients q of each segment driving current are set according to the actual display requirements. It is assumed that the PWM pulse width modulation coefficient of the first segment current i1 is q1 = 1 (when the first segment current is the reference current), the PWM pulse width modulation coefficient of the second segment current i2 is q2, …, and the PWM pulse width modulation coefficient of the nth segment PWM pulse interval is q n ;

[0104] Since the PWM pulse width threshold values V of each subframe are different from each other, when calculating the PWM pulse width interval corresponding to each segment driving current of each subframe, the PWM pulse width threshold value V of the current subframe is first determined. The calculation process of the first subframe is taken as an example for explanation, and the PWM pulse width threshold value is V1. The PWM pulse width interval w k corresponding to the kth segment driving current i k ∈ [x k ,y k ] is calculated according to the following calculation formula:

[0105] The lower limit of the interval is x k = V1 / q k-1 +1;

[0106] The upper limit of the interval is y k = V1 / q k ;

[0107] where k satisfies k ≥ 2, and the PWM pulse width interval of the first segment current i1 is w1 ∈ [0, V1]. The pulse interval calculation of each segment current of the remaining subframes is similar, and only the PWM pulse width threshold value V1 needs to be replaced with the PWM pulse width threshold value V of the subframe.

[0108] In step S14, the original PWM pulse width P of each subframe is obtained. The original PWM pulse width P of each subframe can be obtained by using a specific scattering algorithm (which does not restrict the use of any scattering algorithm) on the original image gray data. These values can be any integer, and the unit of the value is the LED display clock GCLK period, that is, the value is an integer multiple of the display clock period.

[0109] In step S15, the adjusted driving current parameter i and the PWM pulse width conversion value TRAN of each subframe are calculated.

[0110] The step S15 can be realized by the method of Figure 11 .

[0111] In step S11A, the original PWM pulse width P of the current subframe and which subframe the current subframe is are acquired. The original PWM pulse width value P of the subframe is determined by the system scattering algorithm, and it is assumed that the current subframe is the first subframe;

[0112] In step S11B, the pulse width interval in which the original PWM pulse width value P is located is confirmed. Specifically, in combination with the PWM pulse interval W corresponding to the driving current of each segment of each subframe calculated in step S13, the interval to which the original PWM pulse width value P belongs is confirmed, and if the specific interval to which the original PWM pulse width P belongs can be directly confirmed, step S11C is executed; otherwise, if the original PWM pulse width P of the current subframe exceeds the upper limit of the PWM pulse interval W of the maximum current parameter i n n , the upper limit of the first subframe y n = V1 / q n , step S11D is executed.

[0113] In step S11C, the driving current parameter i k corresponding to the interval to which P belongs is selected as the final driving current i (assuming that P∈[V1 / q k-1 +1, V1 / q k ], that is, i = i k , and then step S11E is executed.

[0114] In step S11D, the maximum current parameter i n is selected as the final driving current i, that is, i = i n , and step S11F is executed.

[0115] In step S11E, the PWM pulse conversion value TRAN is calculated. According to the pulse width modulation coefficient qk corresponding to the final driving current ik, the PWM pulse conversion value TRAN corresponding to the original PWM pulse width P can be calculated, and the calculation formula is as follows. After the calculation is completed, step S11G is executed.

[0116] TRAN = P *qk

[0117] In step S11F, the PWM pulse conversion value TRAN is calculated. The final driving current selected in the above step S11D is i n , and the pulse width modulation coefficient corresponding thereto is q n , according to which the PWM pulse conversion value TRAN corresponding to the original PWM pulse width P can be calculated, and the calculation formula is as follows. After the calculation is completed, step S11G is executed.

[0118] TRAN = P *q n ​

[0119] In step SllG, the PWM pulse conversion value TRAN of the subframe is confirmed according to the above calculation, and the final driving current reference i is obtained.

[0120] In step S16, the final driving current parameter i and the final PWM pulse width p of each subframe are outputted for controlling the brightness of the LED.

[0121] The process from the PWM pulse conversion value TRAN to the final PWM pulse width value p in step S16 is described as follows:

[0122] If the driving current parameter value i is not the last section current, i.e. i≠i n , then p=TRAN, i.e. the final PWM pulse width value p is equal to the PWM pulse conversion value TRAN at this time;

[0123] If the driving current parameter value i is the last section current, i.e. i = i n , then the PWM pulse conversion value TRAN is compared with the PWM pulse width setting value W to confirm the final PWM pulse width value p, and there are the following cases:

[0124] Case 1, if TRAN

[0125] Case 2, if TRAN>=W, then the PWM pulse width setting value W is selected as the final PWM pulse width value p, i.e. p =W.

[0126] The above embodiment is further illustrated by examples. In example 1, there are two current parameters to be selected, and it is assumed that the first section current parameter value is i1=I and the second section current parameter value is i2=2I, so the current modulation coefficients d1=1 and d2=2 are obtained. In order to facilitate the example, the pulse width modulation coefficients q1=1 and q2=0.5 are set in this embodiment.

[0127] Firstly, the subframe number m of a frame is set to 8, and the PWM pulse width setting value W of each subframe is set to 252;

[0128] Then, the calibration value g of each subframe is determined. The setting results of the calibration value g of each subframe are shown in Table 1.

[0129] PWM pulse width threshold value V corresponding to each sub-frame driving current parameter is recalculated. According to the algorithm description, the linear coefficient f is set to 1 in this embodiment, and then the PWM pulse threshold value V of each sub-frame can be calculated according to the display width W = 252 of the PWM pulse signal and the determined sub-frame calibration value g in step 2. For example, the pulse width threshold value V1 of the first sub-frame is 252-8 = 244, the pulse width threshold value V8 of the eighth sub-frame is 252-15 = 237, and the calculation results of the PWM pulse width threshold value of each sub-frame are shown in Table 1. The calculation results of the pulse width threshold value V of each sub-frame are shown in Table 1. Figure 12

[0130] The PWM pulse width interval w corresponding to each sub-frame driving current parameter is recalculated. As can be known from the above description of the calculation method of the PWM pulse width interval w, the PWM pulse width interval of the first current in each sub-frame is calculated first. In this example, it can be known from the above pulse width interval calculation method that the pulse width interval w1 of the first current i1 in the first sub-frame is w1 ∈ [0, 244], and the pulse width interval w2 of the second current 2I is w2 ∈ [245, 488]. Similarly, the pulse width interval w1 of the first current I in the second sub-frame is w1 ∈ [0, 240], and the pulse width interval w2 of the second current 2I is w2 ∈ [241, 480]. The PWM pulse width intervals w of the remaining sub-frames are calculated according to the above algorithm, as shown in Table 1.

[0131] Table 1 PWM pulse width interval w of each sub-frame

[0132] Subframe 1 2 3 4 5 6 7 8 Calibration value g 8 12 10 14 9 13 11 15 PWM pulse threshold value 244 240 242 238 243 239 241 237 PWM pulse width interval of the first section current [0,244] [0,240] [0,242] [0,238] [0,243] [0,239] [0,241] [0,237] PWM pulse width interval of the second section current [245,488] [241,480] [243,484] [239,476] [244,486] [240,478] [242,482] [238,474]

[0133] The original PWM pulse width P of each sub-frame is obtained. The width value is calculated according to a specific scattering algorithm (without constraints on the scattering algorithm), which can be any integer, and the unit of the value is the LED display clock GCLK period, that is, the value is an integer multiple of the display clock period. In this example, the full scattering algorithm is used as an example to illustrate the relationship between the original PWM pulse width P of each sub-frame and the original gray data A, as shown in Table 2.

[0134] Table 2 Scattering results of original gray data A

[0135] Original gray data A Subframe 1 Subframe 2 Subframe 3 Subframe 4 Subframe 5 Subframe 6 Subframe 7 Subframe 8 1890 237 236 236 236 237 236 236 236 1891 237 236 237 236 237 236 236 236 1892 237 236 237 236 237 236 237 236 1893 237 237 237 236 237 236 237 236 1894 237 237 237 236 237 237 237 236 1895 237 237 237 237 237 237 237 236 1896 237 237 237 237 237 237 237 237 1897 238 237 237 237 237 237 237 237 1898 238 237 237 237 238 237 237 237 1899 238 237 238 237 238 237 237 237 1900 238 237 238 237 238 237 238 237 1901 238 238 238 237 238 237 238 237 1902 238 238 238 237 238 238 238 237 1903 238 238 238 238 238 238 238 237 1904 238 238 238 238 238 238 238 238 1905 239 238 238 238 238 238 238 238 1906 239 238 238 238 239 238 238 238

[0136] The original PWM pulse width P of each sub-frame and the PWM pulse width interval value w corresponding to each sub-frame driving current parameter are calculated according to the above steps. The final driving current parameter value i and the PWM pulse conversion value TRAN of each sub-frame are calculated. The specific calculation method is as follows:

[0137] ​Assuming the original PWM pulse width P value of the first sub-frame is 100, according to the algorithm, it is known that the value 100 is in the PWM pulse width interval of the first section current I of the first sub-frame, the first section current I is selected as the final driving current of the original PWM pulse width 100 of the first sub-frame, and the PWM pulse width conversion calculation is continued. According to the above algorithm description, the interval current is the first section current, and the PWM conversion calculation is as follows: 100*q1 = 100, that is, the PWM pulse width conversion value TRAN after the PWM pulse conversion calculation is 100, the unit is GCLK (display clock frequency);

[0138] Assuming the original PWM pulse width P value of the first sub-frame is 248, according to the algorithm, it is known that the P value 248 is in the PWM pulse width interval of the second section current 2I of the first sub-frame, the second section current 2I is selected as the final driving current i of the original PWM pulse width 248 of the first sub-frame, and the PWM pulse width conversion calculation is continued. According to the above algorithm description, the interval current is the second section current, and the PWM conversion calculation is as follows: 248*q2 = 124, that is, the PWM pulse width conversion value TRAN after the PWM pulse conversion calculation is 124, the unit is GCLK;

[0139] Assuming the original PWM pulse width P value of the first sub-frame is 490, according to the algorithm, it is known that the P value 490 is not in the PWM pulse width interval of the first section current I and the second section current 2I of the first sub-frame, the second section current parameter value is selected as the final driving current, and then the original PWM pulse width conversion value TRAN is calculated according to the second section current parameter value. According to the above algorithm, the calculation is as follows: 490*q2 = 245, compare the conversion value TRAN with the PWM pulse width set value W, and it is known that 245 < 252, so the PWM conversion value 245 is selected as the final PWM pulse width value, the unit is GCLK.

[0140] Assuming the original PWM pulse width P value of the first sub-frame is 550, according to the algorithm, it is known that the P value 490 is not in the PWM pulse width interval of the first section current I and the second section current 2I of the first sub-frame, the second section current parameter value is selected as the final driving current, and then the original PWM pulse width conversion value TRAN is calculated according to the second section current parameter value. According to the above algorithm, the calculation is as follows: 550*q2 = 275, compare the conversion value TRAN with the PWM pulse width set value W, and it is known that 275 > 252, so the PWM pulse width set value W = 252 is selected as the final PWM pulse width value, the unit is GCLK.

[0141] As shown in Table 3, in the above configuration, the results of implementing drive current modulation and PWM pulse width modulation for each sub-frame whose image gray scale A is 1890-1912, wherein two numbers are used to represent the sub-frame implementing drive current modulation, and PWM pulse width modulation is performed, such as 237-118, indicating that the original PWM pulse width P = 237, and the final PWM pulse width value p is 118.

[0142] Table 3 Results of implementing drive current modulation and PWM pulse width modulation for each sub-frame under full scattering

[0143] Original gray data A Subframe 1 Subframe 2 Subframe 3 Subframe 4 Subframe 5 Subframe 6 Subframe 7 Subframe 8 1890 237 236 236 236 237 236 236 236 1891 237 236 237 236 237 236 236 236 1892 237 236 237 236 237 236 237 236 1893 237 237 237 236 237 236 237 236 1894 237 237 237 236 237 237 237 236 1895 237 237 237 237 237 237 237 236 1896 237 237 237 237 237 237 237 237-118 1897 238 237 237 237 237 237 237 237-118 1898 238 237 237 237 238 237 237 237-118 1899 238 237 238 237 238 237 237 237-118 1900 238 237 238 237 238 237 238 237-118 1901 238 238 238 237 238 237 238 237-118 1902 238 238 238 237 238 238 238 237-118 1903 238 238 238 238-119 238 238 238 237-118 1904 238 238 238 238-119 238 238 238 238-119 1905 239 238 238 238-119 238 238 238 238-119 1906 239 238 238 238-119 239 238 238 238-119 1907 239 238 239 238-119 239 238 238 238-119 1908 239 238 239 238-119 239 238 239 238-119 1909 239 239 239 238-119 239 238 239 238-119 1910 239 239 239 238-119 239 239-119 239 238-119 1911 239 239 239 239-119 239 239-119 239 238-119 1912 239 239 239 239-119 239 239-119 239 239-119

[0144] Correspondingly, the embodiment of the present disclosure also provides a driving device similar to the driving device 110 in the above embodiment, which comprises a gray scale data processing module and a PWM signal generation module. Figure 1

[0145] The gray scale data processing module is configured to set different PWM pulse width threshold values for a plurality of sub-frames and a PWM pulse width setting value, obtain the original PWM pulse width of each sub-frame by using a scattering algorithm according to the original gray scale data of each frame of image, and perform drive current and pulse width modulation for each sub-frame whose original PWM pulse width is greater than the PWM pulse width threshold value, wherein the PWM pulse width threshold values of the plurality of sub-frames are all less than the PWM pulse width setting value, the order of the PWM pulse width threshold values determines the modulation order of the drive current of each sub-frame, and the modulated PWM pulse width is less than or equal to the PWM pulse width setting value of the sub-frame.

[0146] The PWM signal generation module is configured to generate a PWM signal of the corresponding sub-frame according to the modulated PWM pulse width and the drive current, and the PWM signal controls the display of the picture on the panel.

[0147] It should be understood that the above embodiment is described mainly from the LED display device, but it is not limited to the LED display device, and can also be applied to, for example, the LCD display device, the OLED display device.

[0148] Correspondingly, the embodiment of the present disclosure also provides a computer readable storage medium, which stores one or more computer instructions, and the one or more computer instructions implement the functions of the steps or modules in the above embodiment when executed.

[0149] ​Correspondingly, the display driving chip and the electronic device are also provided, the display driving chip implements the functions of the steps or modules in the above embodiments, and the electronic device includes a processor and a memory, the memory stores one or more computer instructions, and the one or more computer instructions are executed by the processor to implement the functions of the steps or modules in the above embodiments.

[0150] It should be understood that the driving method, the driving device, the computer readable storage medium, the display driving chip and the electronic device provided by the embodiments of the present disclosure are all based on the same inventive concept, and the embodiments of the above different subjects can be mutually referred and verified, so the embodiments of some subjects are not described in detail.

[0151] Although the embodiments of the present application are disclosed as above with the preferred embodiments, they are not intended to limit the claims, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application, so the protection scope of the present application should be limited by the scope defined by the claims of the present application.

[0152] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.< / l> < / l> < / l> < / l>

Claims

1. A driving method of a display device, characterized by, The display device comprises a panel, the panel comprises a plurality of pixel units, and a display time of each frame image on the panel is divided into a plurality of sub-frames, and the driving method comprises: setting different PWM pulse width threshold values for the plurality of sub-frames and a PWM pulse signal width setting value, wherein the PWM pulse width threshold values of the plurality of sub-frames are all less than the PWM pulse width setting value; obtaining original PWM pulse widths of the sub-frames according to original gray data of each frame image by using a scattering algorithm; for each sub-frame whose original PWM pulse width is greater than the PWM pulse width threshold value, performing driving current and pulse width modulation, wherein the order of the PWM pulse width threshold values determines the modulation order of the driving currents of the sub-frames, and the modulated PWM pulse width is less than or equal to the PWM pulse width setting value of the sub-frame; and generating a PWM signal of the corresponding sub-frame according to the modulated PWM pulse width and the driving current, wherein the PWM signal is used for controlling the display of the panel, wherein the pulse width modulation comprises: setting a plurality of modulatable currents and a plurality of PWM pulse width modulation coefficients corresponding to the plurality of modulatable currents respectively; for each sub-frame, calculating a plurality of PWM pulse width intervals according to the PWM pulse width threshold value of the sub-frame and the plurality of PWM pulse width modulation coefficients; for each sub-frame, judging whether the original PWM pulse width of the sub-frame is in the plurality of PWM pulse width intervals, if the original PWM pulse width of the sub-frame is in a first PWM pulse width interval in the plurality of PWM pulse width intervals, multiplying the PWM pulse width modulation coefficient corresponding to the first PWM pulse width interval by the original PWM pulse width value to obtain a PWM pulse conversion value, and if the original PWM pulse width value of the sub-frame exceeds the plurality of PWM pulse width intervals, multiplying the PWM pulse width modulation coefficient corresponding to the maximum modulatable current by the original PWM pulse width to obtain a PWM pulse conversion value; obtaining the modulated PWM pulse width of the sub-frame based on the PWM pulse conversion value.

2. The driving method according to claim 1, wherein setting different PWM pulse width threshold values for the plurality of sub-frames comprises: setting different current modulation calibration values for the plurality of sub-frames; and obtaining the PWM pulse width threshold value of each sub-frame according to the following equation (1); W = V +f*g equation (1) wherein W represents the PWM pulse width setting value of each sub-frame, V represents the PWM pulse width threshold value of each sub-frame, g is the current modulation calibration value of each sub-frame, f is greater than 0, and the current modulation calibration values g of the plurality of sub-frames are different from each other.

3. The driving method according to claim 1, wherein The driving current modulation of the plurality of sub-frames further comprises: For each sub-frame, it is judged whether the original PWM pulse width of the sub-frame is in the multiple PWM pulse width intervals. If the original PWM pulse width of the sub-frame is in a first PWM pulse width interval in the multiple PWM pulse width intervals, the modulatable current corresponding to the first PWM pulse width interval is taken as the modulated driving current of the sub-frame. If the original PWM pulse width of the sub-frame exceeds the multiple PWM pulse width intervals, the maximum value of the multiple modulatable currents is taken as the modulated driving current of the sub-frame.

4. The driving method according to claim 1, wherein The final PWM pulse width value is obtained based on the PWM pulse conversion value: If the PWM pulse conversion value is greater than or equal to the PWM pulse signal width setting value, the modulated PWM pulse width of the sub-frame is equal to the PWM pulse signal width setting value; and If the PWM pulse conversion value is less than the PWM pulse signal width setting value, the modulated PWM pulse width of the sub-frame is equal to the PWM pulse conversion value.

5. The driving method according to claim 1, wherein The PWM pulse signal width setting value is an integer multiple of the display clock period.

6. The driving method according to claim 3, wherein The multiple modulatable currents are respectively greater than or equal to the reference current.

7. The driving method according to claim 1, wherein For each sub-frame with an original PWM pulse width not greater than a PWM pulse width threshold value, the reference current is taken as the driving current of each sub-frame, and the PWM pulse width of each sub-frame is kept unchanged.

8. A driving device of a display device, characterized by comprising: It comprises: A grayscale data processing module is configured to set multiple PWM pulse width threshold values different from each other and a PWM pulse signal width setting value for multiple sub-frames, obtain original PWM pulse widths of the multiple sub-frames by using a scattering algorithm according to original grayscale data of each frame of image, for each sub-frame with an original PWM pulse width greater than a PWM pulse width threshold value, perform driving current and pulse width modulation, the pulse width modulation comprises: setting multiple modulatable currents and multiple PWM pulse width modulation coefficients corresponding to the multiple modulatable currents respectively; for each sub-frame, calculate multiple PWM pulse width intervals according to the PWM pulse width threshold value of the sub-frame and the multiple PWM pulse width modulation coefficients; for each sub-frame, judge whether the original PWM pulse width of the sub-frame is in the multiple PWM pulse width intervals. If the original PWM pulse width of the sub-frame is in a first PWM pulse width interval in the multiple PWM pulse width intervals, the PWM pulse width modulation coefficient corresponding to the first PWM pulse width interval is multiplied by the original PWM pulse width value to obtain a PWM pulse conversion value. If the original PWM pulse width value of the sub-frame exceeds the multiple PWM pulse width intervals, the PWM pulse width modulation coefficient corresponding to the maximum modulatable current is multiplied by the original PWM pulse width to obtain a PWM pulse conversion value; and obtain the modulated PWM pulse width of the sub-frame based on the PWM pulse conversion value. The PWM pulse width threshold values of the multiple subframes are all less than the PWM pulse width setting value, and the order of the sizes of the PWM pulse width threshold values determines the modulation order of the driving currents of the multiple subframes, and the modulated PWM pulse width is less than or equal to the PWM pulse width setting value of the subframe. The PWM signal generation module is configured to generate a PWM signal of the corresponding subframe according to the modulated PWM pulse width and the driving current, and the PWM signal is used to control the picture display on the panel of the display device.

9. The drive apparatus according to claim 8, characterized by The gray data processing module sets PWM pulse width threshold values different from each other for the multiple subframes, including: The gray data processing module sets current modulation calibration values different from each other for the multiple subframes, and The PWM pulse width threshold value of each subframe is obtained according to the following equation (1); W = V +f*g equation (1) wherein W represents the PWM pulse width setting value of each subframe, V represents the PWM pulse width threshold value of each subframe, g is the current modulation calibration value of each subframe, f is greater than 0, and the current modulation calibration values g of the multiple subframes are different from each other.

10. The drive apparatus according to claim 8, characterized by The driving current modulation of the gray data processing module further includes: For each subframe, it is judged whether the original PWM pulse width of the subframe is in the multiple PWM pulse width intervals, if the original PWM pulse width of the subframe is in a first PWM pulse width interval in the multiple PWM pulse width intervals, the modulated driving current of the subframe is the modulatable current corresponding to the first PWM pulse width interval, and if the original PWM pulse width of the subframe exceeds the multiple PWM pulse width intervals, the modulated driving current of the subframe is the maximum value of the multiple modulatable currents.

11. The drive apparatus according to claim 8, characterized by The pulse width modulation of the gray data processing module further includes: If the PWM pulse conversion value is greater than or equal to the PWM pulse signal width setting value, the modulated PWM pulse width of the subframe is equal to the PWM pulse signal width setting value; and If the PWM pulse conversion value is less than the PWM pulse signal width setting value, the modulated PWM pulse width of the subframe is equal to the PWM pulse conversion value.

12. The drive apparatus according to claim 8, characterized by The multiple modulatable currents are greater than or equal to the reference current respectively.

13. The drive apparatus according to claim 8, characterized by For each subframe with an original PWM pulse width not greater than the PWM pulse width threshold value, the reference current is used as the driving current of each subframe, and the PWM pulse width of each subframe is kept unchanged.

14. A computer readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to realize the steps of the driving method in any one of claims 1-7.

15. A display driving chip, characterized in that, The display driving device in any one of claims 8-13.

16. An electronic device, comprising: The display driving chip in claim 15.

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