Driving method and driving device of display device

Abstract

The invention provides a driving method and a driving device of a display device. The method comprises the following steps: setting different PWM pulse width thresholds and a PWM pulse signal width set value for a plurality of subframes; obtaining the original PWM pulse width of each subframe by using a scattering algorithm according to the original gray data of each frame of image; driving current and pulse width modulation is carried out on each sub-frame with the original PWM pulse width larger than a PWM pulse width threshold value, the modulation sequence of the driving current of each sub-frame is determined by the size sequence of the PWM pulse width threshold value, and the modulated PWM pulse width is smaller than or equal to the PWM pulse width set 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 picture display on the panel. According to the invention, the defect that the image gray scale is difficult to refine when the brightness is improved by increasing the driving current in the prior art is overcome.

Description

Technical Field

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

[0002] With the rapid advancement of LED (Light Emitting Diode) display technology, the demand for high contrast is also increasing. 18-bit display (using 18 bits to represent the color of a single pixel) has become the universal standard. Increasing the display time can make pixel brightness changes more pronounced, thereby improving contrast. However, this method is limited by the display's refresh rate. Therefore, increasing LED brightness by adjusting the LED drive current is currently a major research direction in the industry.

[0003] The usual practice is to divide a frame into multiple sub-frames and perform PWM control on each sub-frame. Specifically, when the PWM pulse width P of the sub-frame reaches the PWM pulse width setting value W of the sub-frame (that is, P≥W, W represents the maximum time that PWM is turned on in a row of the display), while maintaining the PWM pulse width P=W of the sub-frame unchanged, the driving current of the sub-frame is modulated to achieve display grayscale expansion, thereby obtaining higher brightness.

[0004] However, the above approach also has certain problems. Assuming that the number of subframes m = 8 and the subframe PWM pulse width setting value W = 252, after using SPWM to break up the image grayscale data A, the relationship between the image grayscale data A and the number of subframes g for driving current modulation can be obtained, as shown in the following example: Figure 1 shown.

[0005] When executing the above scheme, in the process of completing the drive current modulation of all sub-frames, the original grayscale A increases by 1 for every increase in the number of sub-frames implementing drive current modulation, and this conclusion is applicable to any number of sub-frames using the above scheme. During the image display process, the original image needs to be processed by the gamma correction curve, such as Figure 2 The figure shows the gamma correction curve. It can be seen that as the grayscale of the original image increases, the discreteness of the grayscale data after gamma correction is very large. For example, if the original grayscale A value of a frame image increases by 1, it can jump directly from 2000 to 2020 after gamma correction; if the original grayscale A value increases by 1 again, it can jump directly from 2020 to 2040 after gamma correction. Figure 1 As shown in FIG, the second increase of the original grayscale by 1 will cause the driving current to be modulated in 20 subframes, which will cause drastic changes in brightness and color temperature.

[0006] To address this issue, pixel-by-pixel grayscale refinement is typically performed, fine-tuning the brightness of each pixel's RGB components individually to achieve a balance between overall brightness and color temperature. However, simultaneous current modulation across multiple subframes causes dramatic changes in brightness and color temperature, posing significant challenges to grayscale refinement and potentially making it impossible to find a balance between overall brightness and color temperature. Summary of the Invention

[0007] An object of the embodiments of the present disclosure is to provide a driving method and a driving device for a display device, wherein the driving method provides a new modulation method of a driving current.

[0008] In a first aspect, an embodiment of the present disclosure provides a method for driving a display device, wherein the display device includes a panel, the panel includes pixel units, and the display time of each frame image on the panel is divided into multiple sub-frames. The driving method includes:

[0009] Setting different PWM pulse width thresholds and a PWM pulse signal width setting value for the multiple subframes, wherein the PWM pulse width thresholds of the multiple subframes are all smaller than the PWM pulse width setting value;

[0010] The original PWM pulse width of each subframe is obtained by using a scattering algorithm based on the original grayscale data of each frame of the image;

[0011] For each subframe in which the original PWM pulse width is greater than the PWM pulse width threshold, performing drive current and pulse width modulation, wherein the order of the PWM pulse width thresholds determines the modulation order of the drive 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

[0012] A PWM signal of a corresponding subframe is generated according to the modulated PWM pulse width and the driving current, and the PWM signal controls the picture display on the panel.

[0013] In some embodiments, setting different PWM pulse width thresholds for the multiple subframes includes:

[0014] Setting different current modulation calibration values ​​for the multiple subframes; and

[0015] The PWM pulse width threshold of each subframe is obtained according to the following equation (1);

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

[0017] Wherein, W represents the PWM pulse width setting value of each subframe, V represents the PWM pulse width threshold 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.

[0018] In some embodiments, modulating the driving current of the plurality of subframes includes:

[0019] Setting multiple segments of modulated current and multiple PWM pulse width modulation coefficients corresponding to the multiple segments of modulated current;

[0020] For each subframe, a plurality of PWM pulse width intervals are calculated according to the PWM pulse width threshold of the subframe and the plurality of PWM pulse width modulation coefficients;

[0021] For each subframe, determine whether the original PWM pulse width of the subframe is within the multiple PWM pulse width intervals. If the original PWM pulse width of the subframe is within a first PWM pulse width interval among the multiple PWM pulse width intervals, use the modulated current corresponding to the first PWM pulse width interval as the modulated drive current of the subframe. If the original PWM pulse width of the subframe exceeds the multiple PWM pulse width intervals, use the maximum value of the multiple modulated currents as the modulated drive current of the subframe.

[0022] In some embodiments, the pulse width modulation of the plurality of subframes comprises:

[0023] For each subframe, determining whether an original PWM pulse width of the subframe is within the multiple PWM pulse width intervals; if the original PWM pulse width of the subframe is within a first PWM pulse width interval among the multiple PWM pulse width intervals, multiplying a 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; if the original PWM pulse width of the subframe exceeds the multiple PWM pulse width intervals, multiplying a PWM pulse width modulation coefficient corresponding to a maximum modulatable current by the original PWM pulse width to obtain a PWM pulse conversion value;

[0024] The modulated PWM pulse width of the subframe is obtained based on the PWM pulse conversion value.

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

[0026] If the PWM pulse conversion value is greater than or equal to the PWM pulse signal width setting value, the PWM pulse width after the sub-frame modulation 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 PWM pulse width after sub-frame modulation 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 multiple modulated currents are respectively greater than or equal to a reference current.

[0030] In some embodiments, for each subframe in which the original PWM pulse width is not greater than the PWM pulse width threshold, 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, an embodiment of the present disclosure provides a driving device for a display device, comprising:

[0032] a grayscale data processing module, configured to set different PWM pulse width thresholds and a PWM pulse signal width setting value for a plurality of subframes, obtain an original PWM pulse width of each subframe using a scattering algorithm based on the original grayscale data of each frame of image, and perform drive current and pulse width modulation for each subframe whose original PWM pulse width is greater than the PWM pulse width threshold, wherein the PWM pulse width thresholds of the plurality of subframes are all less than the PWM pulse width setting value, the order of the PWM pulse width thresholds determines the modulation order of the drive 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;

[0033] The PWM signal generating module is used 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 picture display on the panel of the display device.

[0034] In some embodiments, setting different PWM pulse width thresholds for the multiple subframes includes:

[0035] Setting different current modulation calibration values ​​for the multiple subframes; and

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

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

[0038] Wherein, W represents the PWM pulse width setting value of each subframe, V represents the PWM pulse width threshold 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.

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

[0040] Setting multiple segments of modulated current and multiple PWM pulse width modulation coefficients corresponding to the multiple segments of modulated current;

[0041] For each subframe, a plurality of PWM pulse width intervals are calculated according to the PWM pulse width threshold of the subframe and the plurality of PWM pulse width modulation coefficients;

[0042] For each subframe, determine whether the original PWM pulse width of the subframe is within the multiple PWM pulse width intervals. If the original PWM pulse width of the subframe is within a first PWM pulse width interval among the multiple PWM pulse width intervals, use the modulated current corresponding to the first PWM pulse width interval as the modulated drive current of the subframe. If the original PWM pulse width of the subframe exceeds the multiple PWM pulse width intervals, use the maximum value of the multiple modulated currents as the modulated drive current of the subframe.

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

[0044] For each subframe, determining whether an original PWM pulse width of the subframe is within the multiple PWM pulse width intervals; if the original PWM pulse width of the subframe is within a first PWM pulse width interval among the multiple PWM pulse width intervals, multiplying a 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; if the original PWM pulse width of the subframe exceeds the multiple PWM pulse width intervals, multiplying a PWM pulse width modulation coefficient corresponding to a maximum modulatable current by the original PWM pulse width to obtain a PWM pulse conversion value;

[0045] The modulated PWM pulse width of the subframe is obtained based on the PWM pulse conversion value.

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

[0047] If the PWM pulse conversion value is greater than or equal to the PWM pulse signal width setting value, the PWM pulse width after the sub-frame modulation 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 PWM pulse width after sub-frame modulation is equal to the PWM pulse conversion value.

[0049] In some embodiments, the multiple modulated currents are respectively greater than or equal to a reference current.

[0050] In some embodiments, for each subframe in which the original PWM pulse width is not greater than the PWM pulse width threshold, 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, an embodiment of the present disclosure provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the above-mentioned driving method when the program is executed by a processor.

[0052] In a fourth aspect, an embodiment of the present disclosure provides a display driver chip, comprising the driver device of the display device described above.

[0053] In a fifth aspect, an embodiment of the present disclosure provides an electronic device comprising the display driver chip described above.

[0054] The embodiments of the present disclosure solve the problem of difficulty in refining the grayscale of an image when brightness is increased by increasing the driving current.

[0055] It should be noted that the foregoing general description and the following detailed description are merely exemplary and explanatory and are not restrictive of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The above and other objects, features and advantages of the present application will become more apparent through the description of the embodiments of the present application with reference to the following drawings, in which:

[0057] Figure 1 : is a traditional relationship diagram between the original grayscale data A of an image and the number of drive current modulation subframes g;

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

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

[0060] Figure 4 yes Figure 3 A waveform diagram of a scanning signal in an LED display device;

[0061] Figure 5 is a flow chart of a driving method of an LED display device according to an embodiment of the present disclosure;

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

[0063] Figure 7 The embodiment of the present disclosure is given Figure 6 Schematic diagram of the sub-frame current modulation sequence;

[0064] Figure 8 is a graph showing a mapping relationship between the number of subframes g and the original grayscale data A for implementing current modulation according to an embodiment of the present disclosure;

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

[0066] Figure 9b : is a mapping relationship diagram of the PWM pulse width P and the segmented driving current in an embodiment of the present disclosure;

[0067] Figure 10 A flowchart of the complete calculation process of the final driving current parameter i and the final PWM pulse width P of each subframe proposed in the embodiment of the present disclosure is provided;

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

[0069] Figure 12 A schematic diagram of the PWM pulse width threshold V of multiple sub-frames is given as another example. DETAILED DESCRIPTION

[0070] The present application will be described in more detail below with reference to the accompanying drawings. In each of the drawings, identical elements are represented by similar reference numerals. For the sake of clarity, the various parts in the drawings are not drawn to scale. In addition, 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 Punit are arranged in a first direction (e.g., horizontal direction) and a second direction (e.g., vertical direction) 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 according to the brightness of the LED.

[0072] The driving line DL and the scanning line SL may be arranged on the panel 120, the driving line DL connecting one side of the pixel unit Punit in the second direction, and the scanning line SL connecting the other side of the pixel unit Punit in the first direction. For example, the anode of the LED in the pixel unit Punit is electrically connected to the driving line DL, and the cathode of the LED is electrically connected to the scanning line SL. Although Figure 3 The example shown is referred to as a common cathode structure (in which the cathodes of the LEDs are connected in common), but the disclosed embodiments are not limited to this structure.

[0073] The selection switches SWc1 to SWcL may be arranged in each scan line SL, and determine to which scan line SL the driving current Ie is supplied according to whether the selection switches SWc1 to SWcL are turned on or off.

[0074] Figure 4 yes Figure 3 The waveform diagram of the scanning signal in the LED display device. Figure 3 and Figure 4 One frame is divided into N (N is a natural number) subframes, and in each subframe, the scan signal Scan can be sequentially supplied through each selection switch SWc1 to SWcL. <1> To Scan <l>According to the scanning signal Scan <1> To Scan <l>, the driving current Ie can be sequentially supplied to the first scan line to the Lth scan line.

[0075] The scan line SL is 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 SWc1 to SWcL may be formed on the panel 120 or on a separate substrate, or may be formed in the driving device 110.

[0076] Scan signal Scan <1> To Scan <l>It can be supplied by the drive device 110 or by a separate control device.

[0077] The brightness of the LED arranged in each pixel unit Punit can be determined based on the driving force provided within a predetermined time. The LED is driven by pulse width modulation (PWM), and the brightness is determined based on the on-time ratio in the PWM control time. When the LED is turned on by the driving current Ie, a forward voltage can be formed in the LED, and the driving force supplied to the LED can be obtained by accumulating the product of the forward voltage and the driving current Ie for the on-time in the PWM control time, and the brightness of the LED can be determined based on the driving force. Assuming that the forward voltage and the driving current Ie of the LED are fixed parameters, the driving force can be regarded as a value proportional to the on-time in the PWM control time. According to this principle, the driving device 110 can control the on-time in the PWM control time, thereby controlling the brightness of the LED and the brightness of 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 a 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 may include a grayscale value for each pixel unit Punit. The data processing device 130 may transmit the image data RGB together with the communication clock DCLK to the driving device 110. The driving device 110 may receive the image data RGB based on the communication clock DCLK and obtain the grayscale value for each pixel unit Punit from the image data RGB.

[0080] The driving device 110 may determine the PWM control time for each pixel unit Punit according to the grayscale value, and may perform PWM control on each pixel unit Punit.

[0081] The driving device 110 can perform PWM control on each pixel unit Punit once in one frame, and Figure 4 As shown, a frame can be divided into N subframes to perform PWM control on each pixel unit Punit in each subframe. In combination with the background technology, when the scanning signal Scan <1> To Scan <l>When the pulse width (high level duration) P reaches a set value W, the drive current Ie is modulated while maintaining the pulse width P=W unchanged.

[0082] In order to solve the problem of difficulty in refining the grayscale of an image brought about by the above solution, the embodiment of the present disclosure proposes a driving method for a display device. Figure 5 As shown, the following steps are included.

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

[0084] In step S420 , different PWM pulse width thresholds are set for the multiple subframes, wherein the PWM pulse width thresholds of the multiple subframes are all smaller than the PWM pulse width setting value.

[0085] In step S430, for each subframe where the original PWM pulse width is greater than the PWM pulse width threshold, drive current and pulse width modulation are performed. The order of the PWM pulse width thresholds determines the modulation order of the drive current in each subframe.

[0086] In step S440 , a PWM signal of a corresponding subframe is generated according to the modulated PWM pulse width and the driving current, and the PWM signal controls the screen display on the panel.

[0087] Specifically, the display time of each frame of image is divided into multiple sub-frames according to actual requirements. The original grayscale data of each frame of image is scattered into multiple sub-frames according to a predetermined rule, and the original PWM pulse width P of the sub-frame is obtained based on the grayscale data obtained for each sub-frame. Different PWM pulse width thresholds V are set for each sub-frame (assuming the number of sub-frames is m, which can be expressed as thresholds V1, V2, …, Vm, and they are not equal to each other), and the threshold width V should satisfy being less than the PWM pulse width setting value W. The size relationship of the PWM pulse width thresholds V between sub-frames can be set according to actual requirements. Without further restrictions on the premise that the PWM pulse width thresholds V of each sub-frame are not equal to each other. Moreover, drive current modulation and pulse width modulation are performed on each sub-frame whose original PWM pulse width is greater than the PWM pulse width threshold. The drive current modulation can be implemented in the order of sorting the PWM pulse width thresholds from small to large, so that the sub-frame with a smaller PWM pulse width threshold is driven by current modulation earlier. The setting of the threshold width V < W can achieve current modulation when the sub-frame PWM pulse width P (P < W) is relatively low, making the transition from medium gray level display to high gray level display smoother. In addition, the optimization of different PWM pulse width thresholds V can achieve the purpose of sequentially performing drive current modulation for each sub-frame, which is used to solve the problem of simultaneously performing drive current modulation for multiple sub-frames and can effectively reduce the difficulty of image gray level refinement. Figure 6 An example of the PWM pulse width threshold V with the number of sub-frames m = 8 and the PWM pulse width setting value W = 252 based on this embodiment is given. In this example, the PWM pulse width thresholds V (V1~V8) of each sub-frame are as shown in the figure, and then the current modulation sequence of all sub-frames is as Figure 7 shown as follows: the eighth sub-frame, the fourth sub-frame, the sixth sub-frame, the second sub-frame, the seventh sub-frame, the third sub-frame, the fifth sub-frame, the first sub-frame.

[0088] In some embodiments, referring to Figure 7 as shown, after clarifying the order of performing drive current modulation for each sub-frame, the difference ΔV between the PWM pulse width thresholds V of two adjacent current modulation sub-frames in the above drive current modulation sequence can be further set. For example, Figure 7 in, the difference ΔV = V5 - V3 = 244 - 242 = 2 between the threshold V5 corresponding to the seventh current modulation sub-frame and the threshold V3 corresponding to the sixth current modulation sub-frame. Then, the step gray level ΔA of the original grayscale data A corresponding to driving current modulation of two adjacent current modulation sub-frames is controlled by ΔV, and the relationship is as follows:

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

[0090] In the full-scattering algorithm, the value of h is the number of sub-frames m. The relationship between ΔA and ΔV in the full-scattering algorithm is as Figure 8 As shown in the figure, we can see that Figure 6 The grayscale step ΔA between the seventh current modulation subframe and the sixth current modulation subframe is (V5-V3)·m. At this time, the grayscale step ΔA between adjacent current modulation subframes can be adjusted by the number of subframes m. In other scattering methods, the value of h can be adjusted according to actual needs. In the traditional solution, the grayscale step between any two adjacent current modulation subframes is fixed to ΔA=1. Therefore, this embodiment adjusts the grayscale step ΔA (such as Figure 8 As shown in the figure, after the algorithm is optimized, ΔA = ΔV·m), which can effectively expand the interval length of the original grayscale A corresponding to each driving current segment. Combined with the gamma correction curve, it can be seen that although the image grayscale discreteness is high at high grayscale levels, because the step grayscale ΔA between adjacent current modulation subframes can be adjusted, the probability of simultaneous current modulation in multiple subframes can be significantly reduced, and even the situation where current modulation occurs simultaneously in multiple subframes (more than one). This optimization delays the process of color shift and significantly reduces the difficulty of image grayscale refinement.

[0091] In some embodiments, pulse width modulation of a subframe in which the PWM pulse width P is greater than a PWM pulse width threshold V specifically includes the following operations. To improve display brightness, multiple modulated currents ik (k represents the kth current segment) can be set for the subframe. Correspondingly, each modulated current segment corresponds to a PWM pulse width modulation coefficient qk (k represents the PWM pulse width modulation coefficient when the subframe uses the kth current segment), where ik and qk (k is an integer greater than 1) are in a one-to-one mapping relationship. The PWM pulse width conversion value p after pulse width modulation and the subframe PWM pulse width P are calculated as follows:

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

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

[0094] The above embodiment improves the modulation of the PWM pulse width while performing drive current modulation, thereby achieving dynamic adjustment of the duty cycle, improving the accuracy of image grayscale refinement, and reducing the brightness jump of the image when displaying high grayscale, avoiding the rebound phenomenon.

[0095] In addition, for the case where the sub-frame PWM pulse width P is not less than the pulse width threshold V, there is no need to perform drive current modulation and PWM pulse width P modulation processing. The first current segment (i.e., the reference current I) is selected as the drive current, and the PWM pulse width remains unchanged.

[0096] Of course, in actual image display, changes in image grayscale are arbitrary. For example, when the pulse width P of different subframes changes from greater than V to less than V, the drive current will also be modulated, reducing the drive current and increasing the PWM pulse width. This situation can also be handled according to the above embodiment and will not affect the final image grayscale refinement effect.

[0097] Moreover, considering that the effects of different driving currents on the offset of color coordinates are inconsistent, and the PWM pulse width has certain limitations for color coordinate calibration, although the above embodiment can effectively reduce the difficulty of image grayscale refinement, multi-segment driving current modulation may inevitably occur when implementing this solution, and color coordinate drift will still occur at this time. However, with the help of this algorithm, the problem of abnormal image display can be effectively alleviated.

[0098] Figure 10 A flowchart of a complete calculation process of the final driving current parameter i and the final PWM pulse width P of each subframe proposed in an embodiment of the present disclosure is given.

[0099] In step S10, the number of subframes 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 value g of each subframe is different, and g is greater than or equal to zero.

[0101] In step S12, the PWM pulse width threshold V corresponding to the drive current parameter of each subframe is calculated. Specifically, the linear 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, that is, W = V + f*g, where f satisfies greater than 0. Because the calibration value of each subframe is different, the calculated pulse width threshold V of each subframe is also different.

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

[0103] Illustrate step S13 by way of example. Assume that the known n segment drive current values are i1, i2, i3, … in respectively, and i1 < i2 < i3 < … < in. For example, i1, i2, i3, … in are respectively integer multiples of the reference current I. Correspondingly, the PWM pulse width modulation coefficients q of each segment drive current can be set according to actual display requirements. Assume 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 thresholds V of each sub-frame are different from each other, when calculating the PWM pulse width intervals corresponding to the segment drive currents of each sub-frame, it is first necessary to clarify the PWM pulse width threshold V of the current sub-frame. Taking the calculation process of the first sub-frame as an example for illustration, its PWM pulse width threshold is V1. Calculate the PWM pulse width interval w k corresponding to the kth segment drive current i k ∈[x k ,y k according to the following calculation formula:

[0105] Lower limit of the interval: x k = V1 / q k-1 +1;

[0106] Upper limit of the interval: y k = V1 / q k ;

[0107] where k satisfies k ≥ 2. Specifically, the PWM pulse width interval of the first segment current i1 is w1 ∈ [0, V1]. The calculation of the pulse intervals of the segment currents of the remaining sub-frames is similar, and only need to replace V1 with the PWM pulse width threshold V of the sub-frame where it is located.

[0108] In step S14, obtain the original PWM pulse width P of each sub-frame. The original PWM pulse width P of each sub-frame can be obtained by using a specific scrambling algorithm (there is no restriction on which scrambling algorithm to use) to scramble the original image gray data. These values can be any integer, and the unit of this value is the LED display clock GCLK period, that is, this value is an integer multiple of the display clock period.

[0109] In step S15, calculate the adjusted drive current parameter i and the PWM pulse width conversion value TRAN of each sub-frame.

[0110] Step S15 can be implemented by Figure 11 the method of

[0111] In step S11A, the original PWM pulse width P of the current subframe and the subframe of the current subframe are obtained. 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 of the original PWM pulse width value P is confirmed. Specifically, the interval to which the original PWM pulse width value P belongs is confirmed in combination with the PWM pulse interval W corresponding to each driving current segment of each subframe calculated in step S13. 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 maximum current parameter i n PWM pulse interval W n Upper limit of the first subframe (the upper limit of the first subframe y n = V1 / q n ), then jump to step S11D.

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

[0114] In step S11D, the maximum value of the current parameter i is selected. n As the final driving current i, that is, i = i n , jump to step S11F.

[0115] In step S11E, the PWM pulse conversion value TRAN is calculated. Based on the pulse width modulation coefficient qk corresponding to the final drive current ik, the PWM pulse conversion value TRAN corresponding to the original PWM pulse width P can be calculated using the following formula. After the calculation is complete, the process jumps to step S11G.

[0116] TRAN = P *qk

[0117] In step S11F, the PWM pulse conversion value TRAN is calculated. The final drive current selected in the above step S11D is i n , then the corresponding pulse width modulation coefficient is q n Based on this, the PWM pulse conversion value TRAN corresponding to the original PWM pulse width P can be calculated. The calculation formula is as follows. After the calculation is completed, jump to step S11G.

[0118] TRAN = P *q n

[0119] In step S11G, according to the above calculation, the PWM pulse conversion value TRAN of the subframe can be confirmed, and finally the drive current reference i.

[0120] In step S16, the final drive current parameter i and the final PWM pulse width p of each subframe are output to control the brightness of the LED.

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

[0122] If the drive current parameter value i is not the last segment of current, that is, i ≠ i n , at this time, let p = TRAN, that is, the final PWM pulse width value p is equal to the PWM pulse conversion value TRAN at this time;

[0123] If the drive current parameter value i is the last segment of current, that is, i = i n , then it is necessary to compare the PWM pulse conversion value TRAN with the PWM pulse width setting value W to confirm the final PWM pulse width value p. There are the following situations:

[0124] Situation 1, if TRAN < W, then the final PWM pulse width value p is equal to the PWM conversion value of TRAN, that is, p = TRAN;

[0125] Situation 2, if TRAN >= W, then select the PWM pulse width setting value W as the final PWM pulse width value p, that is, p = W.

[0126] Next, the above embodiments will be further illustrated by examples. In Example 1, there are two current parameters to choose from. Assume that the first segment current parameter value is i1 = I, and the second segment current parameter value is i2 = 2I. It can be known that the current modulation coefficients are d1 = 1 and d2 = 2. For the convenience of example, in this embodiment, the pulse width modulation coefficients are set as q1 = 1 and q2 = 0.5.

[0127] First, set the number of subframes m in one frame to 8, and set the PWM pulse width setting value W for each subframe to 252;

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

[0129] Then calculate the PWM pulse width threshold V corresponding to the driving current parameter of each subframe. According to the algorithm description, in this embodiment, the linear coefficient f is set to 1. Then, the PWM pulse threshold V of each subframe can be calculated based on the PWM pulse signal display width W=252 and the calibration value g of each subframe determined in step 2. For example, the pulse width threshold V1 of the first subframe is 252-8=244, and the pulse width threshold V8 of the eighth subframe is 252-15=237. The calculation results of the PWM pulse width thresholds of the remaining subframes are shown in Table 1. The calculation results of the pulse width threshold V of each subframe are shown in the schematic diagram. Figure 12 As shown;

[0130] Then calculate the PWM pulse width interval w corresponding to the drive current parameters of each subframe. Combined with the calculation method of the PWM pulse width interval w described above, it can be seen that the PWM pulse width interval of the first current segment in each subframe is calculated first. In this example, applying the above pulse width interval calculation method, it can be seen that the pulse width interval of the first current segment i1 of the first subframe is w1∈[0,244], and the pulse width interval of the second current segment 2I is w2∈[245,488]. Similarly, it can be calculated that the pulse width interval of the first current segment I of the second subframe is w1∈[0,240], and the pulse width interval of the second current segment 2I is w2∈[241,480]. According to the above algorithm, the PWM pulse width interval w of the remaining subframes is calculated respectively, as shown in Table 1.

[0131] Table 1 PWM pulse width interval w of each subframe Subframe 1 2 3 4 5 6 7 8 Calibration value g 8 12 10 14 9 13 11 15 PWM pulse threshold 244 240 242 238 243 239 241 237 PWM pulse width interval of the first current [0,244] [0,240] [0,242] [0,238] [0,243] [0,239] [0,241] [0,237] PWM pulse width interval of the second current [245,488] [241,480] [243,484] [239,476] [244,486] [240,478] [242,482] [238,474]

[0132] Get the original PWM pulse width P of each subframe. This width is calculated based on a specific scattering algorithm (no constraints are placed on the scattering algorithm). Its value can be any integer, and the unit of this value is the LED display clock GCLK period, that is, the value is an integer multiple of the display clock period. This example uses the full scattering algorithm as an example to illustrate the relationship between the original PWM pulse width P of each subframe and the original grayscale data A, as shown in Table 2.

[0133] Table 2 The results of breaking up the original grayscale A Original grayscale 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

[0134] Based on the original PWM pulse width P of each subframe and the PWM pulse width interval value w corresponding to the drive current parameter of each subframe calculated in the above steps, the final drive current parameter value i and the PWM pulse conversion value TRAN after adjustment of each subframe are calculated. The specific calculation method is as follows:

[0135] Assuming the original PWM pulse width P value of the first subframe is 100, the algorithm determines that this value 100 is within the PWM pulse width interval of the first current segment I of the first subframe. Therefore, the first current segment I is selected as the final driving current for the original PWM pulse width 100 of the first subframe. Continuing with the PWM pulse width conversion calculation, the algorithm describes that the current in this interval is the first current segment. The PWM conversion calculation is as follows: 100*q1 = 100, meaning that the PWM pulse width conversion value TRAN after the PWM pulse conversion calculation is 100, in units of GCLK (display clock frequency).

[0136] Assuming the original PWM pulse width P value of the first subframe is 248, the algorithm determines that this P value 248 is within the PWM pulse width interval of the second current segment 2I of the first subframe. Therefore, the second current segment 2I is selected as the final driving current i for the original PWM pulse width 248 of subframe 1. Continuing with the PWM pulse width conversion calculation, the algorithm describes that the current in this interval is the second current segment. The PWM conversion calculation is as follows: 248*q2 = 124, meaning that the PWM pulse width conversion value TRAN after the PWM pulse conversion calculation is 124, in units of GCLKs.

[0137] Assuming the original PWM pulse width P value of the first subframe is 490, the algorithm determines that the P value 490 is not within the PWM pulse width range of the first current segment I and the second current segment 2I of the first subframe. Therefore, the second current segment parameter value is selected as the final drive current. The original PWM pulse width conversion value TRAN is then calculated based on the second current segment parameter value. According to the aforementioned algorithm, the conversion value TRAN is calculated as follows: 490*q2 = 245. This conversion value TRAN is compared with the PWM pulse width setting value W. Since 245 < 252, the PWM conversion value 245 is used as the final PWM pulse width value, in units of GCLK.

[0138] Assuming the original PWM pulse width P value of the first subframe is 550, the algorithm determines that the P value of 490 is not within the PWM pulse width range of the first current segment I and the second current segment 2I of the first subframe. Therefore, the second current segment parameter value is selected as the final drive current. The original PWM pulse width conversion value TRAN is then calculated based on the second current segment parameter value. According to the aforementioned algorithm, the conversion value TRAN is calculated as follows: 550*q2 = 275. This conversion value TRAN is compared with the PWM pulse width setting value W. Since 275>252, the PWM pulse width setting value W = 252 is used as the final PWM pulse width value (unit: GCLK).

[0139] As shown in Table 3, under the above configuration, when the image grayscale A of each subframe is 1890~1912, the results of driving current modulation and PWM pulse width modulation are implemented in each subframe under full fragmentation. Two numbers are used to represent the subframes implementing driving current modulation and PWM pulse width modulation, such as 237-118, indicating that the original PWM pulse width P = 237, and the final PWM pulse width value p is 118.

[0140] Table 3 Results of driving current modulation and PWM pulse width modulation in each subframe under full fragmentation Original grayscale 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

[0141] Accordingly, the present disclosure also provides a method similar to Figure 1 The driving device 110 in the embodiment includes a grayscale data processing module and a PWM signal generating module.

[0142] The grayscale data processing module is used to set different PWM pulse width thresholds and a PWM pulse signal width setting value for multiple subframes, and use a scattering algorithm to obtain the original PWM pulse width of each subframe based on the original grayscale data of each frame of the image. For each subframe whose original PWM pulse width is greater than the PWM pulse width threshold, drive current and pulse width modulation are performed, wherein the PWM pulse width thresholds of the multiple subframes are all less than the PWM pulse width setting value, the order of the PWM pulse width thresholds determines the modulation order of the drive 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.

[0143] The PWM signal generating module is used to generate a PWM signal of a corresponding subframe according to the modulated PWM pulse width and driving current. The PWM signal controls the screen display on the panel.

[0144] It should be understood that although the above embodiments are mostly described from the perspective of LED display devices, they are not limited to LED display devices, and can also be applied to, for example, LCD display devices and OLED display devices.

[0145] Accordingly, an embodiment of the present disclosure further provides a computer-readable storage medium, which stores one or more computer instructions. When the one or more computer instructions are executed, the functions of the steps or modules in the above embodiments are implemented.

[0146] Accordingly, an embodiment of the present disclosure also provides a display driver chip, which implements the functions of the steps or modules in the above embodiments. At the same time, an electronic device is also provided, including a processor and a memory, wherein the memory stores one or more computer instructions, which implement the functions of the steps or modules in the above embodiments when executed by the processor.

[0147] It should be understood that the driving method, driving device, computer-readable storage medium, display driver chip and electronic device provided in the embodiments of the present disclosure are all based on the same inventive concept, and the embodiments of the above-mentioned different topics can be referenced and verified with each other. Therefore, the embodiments of certain topics are not described in detail in this article.

[0148] Although the embodiments of the present application are disclosed as preferred embodiments as above, they are not intended to limit the claims. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

[0149] The foregoing is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application are intended to be within the scope of protection of the present application.< / l> < / l> < / l> < / l>

Claims

1. A method for driving a display device, characterized in that: The display device includes a panel, the panel includes pixel units, and the display time of each frame image on the panel is divided into multiple subframes. The driving method includes: Setting different PWM pulse width thresholds and a PWM pulse signal width setting value for the multiple subframes, wherein the PWM pulse width thresholds of the multiple subframes are all smaller than the PWM pulse width setting value; The original PWM pulse width of each subframe is obtained by using a scattering algorithm based on the original grayscale data of each frame of the image; For each subframe in which the original PWM pulse width is greater than the PWM pulse width threshold, performing drive current and pulse width modulation, wherein the order of the PWM pulse width thresholds determines the modulation order of the drive 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 A PWM signal of a corresponding subframe is generated 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.

2. The driving method according to claim 1, wherein: Setting different PWM pulse width thresholds for the multiple subframes includes: Setting different current modulation calibration values ​​for the multiple subframes; and The PWM pulse width threshold 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 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.

3. The driving method according to claim 1, wherein: Modulating the driving current of the plurality of subframes includes: Setting multiple segments of modulated current and multiple PWM pulse width modulation coefficients corresponding to the multiple segments of modulated current; For each subframe, a plurality of PWM pulse width intervals are calculated according to the PWM pulse width threshold of the subframe and the plurality of PWM pulse width modulation coefficients; For each subframe, determine whether the original PWM pulse width of the subframe is within the multiple PWM pulse width intervals. If the original PWM pulse width of the subframe is within a first PWM pulse width interval among the multiple PWM pulse width intervals, use the modulated current corresponding to the first PWM pulse width interval as the modulated drive current of the subframe. If the original PWM pulse width of the subframe exceeds the multiple PWM pulse width intervals, use the maximum value of the multiple modulated currents as the modulated drive current of the subframe.

4. The driving method according to claim 3, wherein: The pulse width modulation of the plurality of subframes comprises: For each subframe, determining whether an original PWM pulse width of the subframe is within the multiple PWM pulse width intervals; if the original PWM pulse width of the subframe is within a first PWM pulse width interval among the multiple PWM pulse width intervals, multiplying a 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; if the original PWM pulse width of the subframe exceeds the multiple PWM pulse width intervals, multiplying a PWM pulse width modulation coefficient corresponding to a maximum modulatable current by the original PWM pulse width to obtain a PWM pulse conversion value; The modulated PWM pulse width of the subframe is obtained based on the PWM pulse conversion value.

5. The driving method according to claim 4, 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 PWM pulse width after the sub-frame modulation 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 PWM pulse width after sub-frame modulation is equal to the PWM pulse conversion value.

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

7. The driving method according to claim 3, wherein: The multiple segments of modulated current are respectively greater than or equal to a reference current.

8. The driving method according to claim 1, wherein: For each subframe in which the original PWM pulse width is not greater than the PWM pulse width threshold, the reference current is used as the driving current of each subframe, and the PWM pulse width of each subframe is kept unchanged.

9. A driving device for a display device, characterized in that: include: a grayscale data processing module, configured to set different PWM pulse width thresholds and a PWM pulse signal width setting value for a plurality of subframes, obtain an original PWM pulse width of each subframe using a scattering algorithm based on the original grayscale data of each frame of image, and perform drive current and pulse width modulation for each subframe whose original PWM pulse width is greater than the PWM pulse width threshold, wherein the PWM pulse width thresholds of the plurality of subframes are all less than the PWM pulse width setting value, the order of the PWM pulse width thresholds determines the modulation order of the drive 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; The PWM signal generating module is used to generate a PWM signal of a 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.

10. The driving device according to claim 9, characterized in that The step of setting different PWM pulse width thresholds for the plurality of subframes comprises: Setting different current modulation calibration values ​​for the multiple subframes; and The PWM pulse width threshold 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 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.

11. The driving device according to claim 9, characterized in that The driving current modulation of the grayscale data processing module includes: Setting multiple segments of modulated current and multiple PWM pulse width modulation coefficients corresponding to the multiple segments of modulated current; For each subframe, a plurality of PWM pulse width intervals are calculated according to the PWM pulse width threshold of the subframe and the plurality of PWM pulse width modulation coefficients; For each subframe, determine whether the original PWM pulse width of the subframe is within the multiple PWM pulse width intervals. If the original PWM pulse width of the subframe is within a first PWM pulse width interval among the multiple PWM pulse width intervals, use the modulated current corresponding to the first PWM pulse width interval as the modulated drive current of the subframe. If the original PWM pulse width of the subframe exceeds the multiple PWM pulse width intervals, use the maximum value of the multiple modulated currents as the modulated drive current of the subframe.

12. The driving device according to claim 11, characterized in that The pulse width modulation of the grayscale data processing module includes: For each subframe, determining whether an original PWM pulse width of the subframe is within the multiple PWM pulse width intervals; if the original PWM pulse width of the subframe is within a first PWM pulse width interval among the multiple PWM pulse width intervals, multiplying a 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; if the original PWM pulse width of the subframe exceeds the multiple PWM pulse width intervals, multiplying a PWM pulse width modulation coefficient corresponding to a maximum modulatable current by the original PWM pulse width to obtain a PWM pulse conversion value; The modulated PWM pulse width of the subframe is obtained based on the PWM pulse conversion value.

13. The driving device according to claim 12, characterized in that The pulse width modulation of the grayscale data processing module also includes: If the PWM pulse conversion value is greater than or equal to the PWM pulse signal width setting value, the PWM pulse width after the sub-frame modulation 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 PWM pulse width after sub-frame modulation is equal to the PWM pulse conversion value.

14. The driving device according to claim 11, characterized in that The multiple segments of modulated current are respectively greater than or equal to a reference current.

15. The driving device according to claim 9, characterized in that For each subframe in which the original PWM pulse width is not greater than the PWM pulse width threshold, the reference current is used as the driving current of each subframe, and the PWM pulse width of each subframe is kept unchanged.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the driving method according to any one of claims 1 to 8 are implemented.

17. A display driver chip, characterized in that: The driving device comprises the driving device according to any one of claims 9 to 15.

18. An electronic device, characterized in that: Including the display driver chip according to claim 17.

Images