A dimming method of an organic light emitting display device

Abstract

The application discloses a light adjusting method of an organic light emitting display device, which comprises generating an EM signal by modulating an EM_STV signal and a clock signal, the EM_STV signal comprising a plurality of high level pulses in a frame; and changing the pulse width of one or more high level pulses in the EM_STV signal with the period of the clock signal as a minimum unit when the DBV value changes. The application avoids the occurrence of DBV drop in the EM signal modulation process, improves the smoothness of light adjustment, and is applicable to different clock signal periods.

Description

Technical Field

[0001] This invention relates to the field of OLED display driving, specifically to a dimming method for an organic light-emitting display device. Background Technology

[0002] Currently, in the OLED display field (consumer mobile phones, wearables, automotive, etc.), there are three main ways to adjust brightness: AC dimming, DC dimming, and AC / DC hybrid dimming.

[0003] DC dimming: This usually refers to adjusting the light-emitting current by adjusting the magnitude of the source voltage, that is, the magnitude of the gate drive voltage in the pixel circuit, thereby adjusting the brightness of the OLED unit.

[0004] AC dimming typically refers to maintaining a constant source voltage value. This means the gate drive voltage in the pixel circuit and the current flowing through the OLED unit remain unchanged. Instead, the visual brightness effect is achieved through black pixel insertion. Generally, OLED display panels control the ratio of high to low levels of the EM signal. When the EM signal is high, the OLED unit does not emit light (equivalent to black pixel insertion); when the EM signal is low, the OLED unit emits light. The final perceived brightness is the combined effect of these two factors.

[0005] Figure 1 This diagram illustrates different dimming methods. DC dimming, where brightness is adjusted by changing the data voltage (Vdata), is typically used at higher brightness levels. AC dimming, where brightness is adjusted by varying the high and low ratios of the EM signal (Emit), is typically used at low to medium brightness levels. At low brightness, dimming can also be achieved simultaneously using both the data voltage and EM signal, i.e., AC / DC hybrid dimming. Figure 2 A diagram showing the dimming mode correspondence when DBV (Display Brightness Value) is at different Gamma Bands is presented.

[0006] like Figure 3 As shown, during the AC dimming stage, the emission time ratio (Emit Duty, or simply Duty value) of the EM signal is adjusted according to the changes in DBV. The emission time ratio Duty value can be represented by the high and low level ratio of the EM signal, specifically, the percentage of the total time when the OLED is in a low-level ON state, i.e.: Duty = T B / (T A +T B ()×100%; the value range is 0 to 100%.

[0007] like Figure 4As shown, the duty value can be changed by altering the pulse width of each high-level EM signal pulse within a frame, as indicated by the shaded area in the figure. A single frame can include multiple high-to-low level switching of the EM signal. The OLED unit emits light when the EM signal is low. The Pulse count is defined as the number of times the OLED unit emits light within a frame (i.e., the number of times it switches to low level within a frame, which is also equal to the number of high-level pulses). Currently, applications such as mobile phones generally support at least four EM signals, with common Pulse counts ranging from 1 to 32.

[0008] During AC dimming, since the actual output EM signal is formed under the modulation of the light-start signal (EM_STV signal) and the clock signal (clock signal and xclock signal), the duty adjustment of the EM_STV signal may not necessarily be reflected in the EM signal (this inconsistency is also known as DBV drop). Taking a clock signal period of 4 lines (4H) as an example, as follows... Figure 5 As shown, because the rising and falling edges of the output EM signal are modulated by the falling edges of the clock and xclock signals respectively, even if the pulse width of the EM_STV signal is 4H, the actual output is still 2H (similarly, when the pulse width of the EM_STV signal is 8H, the actual output is still 6H). Therefore, if the DBV change is mapped to the EM_STV signal to increase each pulse width by 2H, the output EM signal will maintain the duty value of the previous DBV, and no actual brightness adjustment will occur. For a frame with four pulses, if the DBV change is mapped to the EM_STV signal with a total pulse width change of 8H in each frame, and this is evenly distributed across the four pulses, the actual output EM signal will still be consistent with the previous one, the brightness will not change, and the smoothness of the dimming will decrease.

[0009] Due to the different circuit structures and driving methods of different GOAs (shift registers for EM signals), the clock signals used typically have two periods: 4H or 2H. Therefore, the same EM_STV duty adjustment method cannot be used for different periods; the corresponding duty adjustment method needs to be set according to the clock signal period length to improve the smoothness of dimming.

[0010] Additionally, extra attention should be paid to the Duty value and Pulse count adjustment methods during the conversion between AC and DC dimming. Otherwise, DBV drops may occur.

[0011] Therefore, how to set the duty adjustment mode of the EM_STV signal to avoid the occurrence of DBV phenomenon, improve the smoothness of dimming, and be applicable to modulation of different clock signal periods is an urgent problem to be solved. Summary of the Invention

[0012] The purpose of this invention is to provide a dimming method for organic light-emitting display devices, which avoids the occurrence of DBV phenomenon, improves the smoothness of dimming, and is applicable to different clock signal cycles.

[0013] To achieve the above objectives, the present invention provides a dimming method for an organic light-emitting display device, comprising generating an EM signal by modulating an EM_STV signal and a clock signal, wherein the EM signal is used to drive an OLED cell;

[0014] The EM_STV signal includes multiple high-level pulses within one frame;

[0015] When the DBV value changes, the total change in pulse width of each frame of high-level pulses is obtained based on the change in the DBV value. Based on the total change in pulse width, the pulse width of one or more high-level pulses in the EM_STV signal is changed using the period of the clock signal as the smallest unit.

[0016] Preferably, the pulse width of the high-level pulse conforms to the form (a+b·n)H, where H is the duration corresponding to scanning one row of OLED cells, b is the period value of the clock signal in units of H, n is an integer, a is the basic pulse width value of the high-level pulse in units of H; b / 2≤a≤b, and the portion of a exceeding b / 2 is not included in the total pulse width of the high-level pulse in each frame.

[0017] Preferably, the pulse widths of the various high-level pulses within each frame differ from each other by no more than one clock cycle.

[0018] Preferably, when the pulse widths of the various high-level pulses within a frame are not all equal, the high-level pulses are set to have a longer pulse width according to a skip interval.

[0019] Preferably, when the DBV value remains constant and the pulse widths of the various high-level pulses within a frame are not all equal, pulse width jitter is enabled to make the average pulse width of the various high-level pulses in multiple frames tend to be equal.

[0020] Another aspect of the present invention provides a dimming method for an organic light-emitting display device, comprising generating an EM signal by modulating an EM_STV signal and a clock signal, wherein the EM signal is used to drive an OLED cell;

[0021] The dimming method includes fill-up stage dimming;

[0022] During the Fill-up dimming stage, the EM_STV signal includes at least one first high-level pulse and at least one second high-level pulse; the pulse width and number of the first high-level pulses remain unchanged during the Fill-up dimming stage.

[0023] The pulse width of the first high-level pulse is (a+b·n0)H, where H is the duration of scanning one row of OLED cells, b is the period of the clock signal in units of H, n0 is a preset positive integer, and a is the base pulse width of the high-level pulse in units of H; b / 2≤a≤b, and the portion of a exceeding b / 2 is not included in the total pulse width of the high-level pulses in each frame; the pulse width of the second high-level pulse conforms to the form (a+b·k)H, where k is an integer and k≤n0;

[0024] During dimming in the Fill-up stage, when the DBV value changes, the total change in pulse width of the high-level pulses in each frame is obtained based on the change in the DBV value; based on the total change in pulse width, the number of second high-level pulses with a pulse width based on the base pulse width value is increased or decreased in the EM_STV signal, and / or, the pulse width of one or more second high-level pulses in the EM_STV signal is changed using the period of the clock signal as the smallest unit.

[0025] Preferably, the dimming method further includes Sequential stage dimming;

[0026] During the Sequential dimming stage, the EM_STV signal includes multiple high-level pulses within one frame, and the pulse width of each high-level pulse conforms to the form (a+b·n)H, where n is an integer and n≥n0;

[0027] During the dimming in the Sequential stage, when the DBV value changes, the total change in the pulse width of the high-level pulses in each frame is obtained based on the change in the DBV value; based on the total change in the pulse width, the pulse width of one or more high-level pulses in the EM_STV signal is changed using the period of the clock signal as the smallest unit.

[0028] Preferably, during the Fill-up dimming stage, the pulse widths of the second high-level pulses within each frame differ by no more than one clock signal cycle; during the Sequential dimming stage, the pulse widths of the high-level pulses within each frame differ by no more than one clock signal cycle.

[0029] Preferably, during the fill-up dimming stage, when the pulse widths of the second high-level pulses within a frame are not all equal, the second high-level pulses are set to have a longer pulse width according to a skip interval; during the sequential dimming stage, when the pulse widths of the high-level pulses within a frame are not all equal, the high-level pulses are set to have a longer pulse width according to a skip interval.

[0030] Preferably, when the DBV value remains constant and the pulse widths of the various high-level pulses within a frame are not all equal, pulse width jitter is enabled to make the average pulse width of the various high-level pulses in multiple frames tend to be equal.

[0031] Preferably, during the fill-up dimming stage, when the DBV value remains unchanged and the pulse widths of the second high-level pulses within a frame are not all equal, pulse width jitter is enabled on the second high-level pulses to make the average pulse width of the second high-level pulses in multiple frames tend to be equal.

[0032] Preferably, during the Fill-up dimming stage, when the DBV value remains constant and the pulse widths of the second high-level pulses within a frame are not all equal, pulse width jitter is enabled on the second high-level pulses to make the average pulse width of the second high-level pulses in multiple frames tend to be equal; while during the Sequential dimming stage, when the DBV value remains constant and the pulse widths of the high-level pulses within a frame are not all equal, pulse width jitter is enabled to make the average pulse width of the high-level pulses in multiple frames tend to be equal.

[0033] Preferably, the period of the clock signal is selected from 2H or 4H; the number of the first high-level pulses is 1.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. This invention takes into account the influence of the clock signal period on the modulation of the EM signal. By setting the pulse width of the high-level pulse in an increasing or decreasing manner with the clock signal period as the smallest unit, the pulse width of each high-level pulse in a frame can be set independently in the case of multiple pulses, so as to avoid the occurrence of DBV phenomenon, improve the smoothness of dimming, and be applicable to different clock signal periods.

[0036] 2. This invention uses pulse width jitter settings to make the average value of the pulse width of the high-level pulse uniform across multiple frames, resulting in a more uniform display effect. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of an existing OLED cell driving method;

[0038] Figure 2 This is a schematic diagram of dimming modes in the prior art;

[0039] Figure 3 and Figure 4 This is a schematic diagram of an EM signal in the prior art;

[0040] Figure 5 This is a schematic diagram illustrating the DBV drop phenomenon in existing technologies.

[0041] Figures 6 to 10 This is a schematic diagram of Example 1;

[0042] Figures 11 to 13 This is a schematic diagram of Example 2;

[0043] In the diagram: PVDD / PVEE: First and second power supply voltage terminals; Emit: EM signal terminal; Vdata: data voltage signal terminal; Id: drive current; GB1~GB10: maximum grayscale value corresponding to each Gamma Band; Nor1 / HBM: typical brightness and high brightness mode brightness; A / B / T A / T B : High level, low level, high level duration (i.e., pulse width of the high level pulse), low level duration; EM_STV: Light-up start signal; Clock / Xclock: Clock signal; EM0 / EM1: Light-up signal (EM signal); frame_k: k-th frame; #1 / #2 / #3 / #4 High-level pulse sequence number. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Example 1

[0046] This embodiment illustrates the duty adjustment method for EM_STV when the clock signal period is 4H. H is a time unit, representing the duration of scanning one row of OLED cells in an organic light-emitting display device. One frame is equal to the number of rows of OLED cells in the display device multiplied by H. Therefore, (100% - Duty) can be multiplied by the number of rows of OLED cells to calculate the total pulse width of the high-level pulses required for the EM signal or EM_STV signal within one frame. This total pulse width can then be distributed among one or more high-level pulses. Taking gradual adjustment from high DBV to low DBV as an example, the AC dimming shown in this embodiment can be divided into two stages: the first stage, where the EM_STV signal changes from a small number of pulses (usually 1) to a larger number of pulses until all pulse widths are equal, is called the Fill-up stage; the second stage, where multiple pulses are used while maintaining a constant number of pulses and gradually increasing pulse widths, is called the Sequential stage. In other embodiments, one of the two adjustment methods can also be used alone for duty adjustment of the EM_STV signal throughout the entire AC dimming stage.

[0047] like Figure 6 As shown, in the Fill-up stage, taking a Pulse count of 4 as an example, the initial pulse width of the first high-level pulse (frame_0) is (2+4n)H, where n is an integer. During the gradual adjustment process, a high-level pulse with the lowest pulse width is first added at the time nodes corresponding to each newly added pulse. Then, at the time nodes corresponding to the third (#3), second (#2), and fourth (#4) high-level pulses within a frame, a high-level pulse with a basic pulse width of 2H is added (frame_0~3). Then, the corresponding pulses are sequentially increased by 4H in the order of #3, #2, and #4 (after frame_3) until the pulse width of each high-level pulse reaches (2+4n)H. Figure 6 In the illustration, the Duty value of the EM_STV signal decreases sequentially with each frame. Each frame corresponds to the EM_STV signal mapped to each DBV value in that stage. In actual dimming, the corresponding EM_STV signal can be generated according to the target DBV value to be adjusted. That is, the pulse width of the original pulse remains unchanged at (2+4n)H, and the sum of the required pulse widths is allocated to each newly added pulse, so that the pulse width of each pulse is in the form of (2+4k)H, where k is an integer (the remainder less than 4H after allocation can be discarded or padded to 4H for processing, so the accuracy of the pulse width sum adjustment, i.e., the adjustment step size, is 4H). At this time, the Duty value of the STV_EM signal is equal to the Duty value of the required EM signal output. In a preferred embodiment, the pulse widths corresponding to each newly added pulse do not differ from each other by more than 4H; in some other embodiments, they can also differ by multiples of 4H, but the maximum pulse width does not exceed (2+4n)H. Since the pulse width adjustment step size is relatively small (2H) during frames_0 to 3, frames_1 to 3 can be combined into a single adjustment step size. That is, after frame_0, the next DBV value directly corresponds to frame_3, skipping frames_1 and frame_2. When adding more pulses, such as increasing the Pulse value from 1 to 8, pulses can be added or widened in a similar skipping interval manner, for example, in the order of #5, #3, #7, #2, #6, #4, #8 (#1 to #8 represent the nth pulse in a frame, and the original pulse corresponds to #1), etc.

[0048] like Figure 7 As shown, in the Sequential stage, taking Pulse number 4 as an example, the pulse width of the initial 4 high-level pulses is (2+4n)H, where n is an integer. During the gradual adjustment process, frames_1 to 4, within one frame, the pulse width of each high-level pulse is increased by 4H in sequence according to the jump interval of #1, #3, #2, and #4. Figure 7In the illustration, the Duty value of the EM_STV signal decreases sequentially with each frame. Each frame corresponds to the EM_STV signal mapped to each DBV value in that stage. In actual dimming, the corresponding EM_STV signal can be generated according to the actual target DBV value to be adjusted. That is, the sum of the required pulse width changes is distributed to each high-level pulse in units of 4H (the remainder less than 4H can be discarded or padded to 4H units for processing, so the adjustment step size of the sum of pulse widths is 4H). In a preferred embodiment, the pulse widths corresponding to each high-level pulse do not differ from each other by more than 4H; in other embodiments, they may differ by multiples of 4H. For example, when the total pulse width to be varied within each frame is 8H, this 8H pulse width can be added to the same pulse of the EM_STV signal, or it can be divided into two 4H pulse widths and added to two different pulses, neither of which will cause a drop in DBV. However, in the existing technology, the adjustment method with equal pulse widths, allocating 8H to the four pulses of the EM_STV signal, and adding 2H to each pulse will not actually change the EM signal, thus causing a drop in DBV. Therefore, an actual increase of 16H in the total pulse width is needed to reduce the Duty value of the EM signal. Therefore, compared with the existing technology, this embodiment has a smoother AC dimming effect in multi-pulse EM signals. In some other embodiments, the number of pulses is other than 8. When dimming, the pulse width of each high-level pulse can be increased in a similar way to the jump interval. For example, the pulse width of each high-level pulse can be increased by 4H in the order of #1, #5, #3, #7, #2, #6, #4, #8. After the total pulse width increases by 8 times 4H, the pulse width of each high-level pulse increases from (2+4n)H to (2+4n+4)H respectively.

[0049] like Figure 8 As shown, in a preferred embodiment, during the DBV keep phase, if the pulse widths of the various high-level pulses are not all equal, pulse width dithering can be enabled to further homogenize the display effect. The corresponding case where pulse width dithering is not enabled is denoted as dither off. Specifically, when pulse width dithering is enabled, the pulse width values ​​of the various high-level pulses within a frame are exchanged or rotated in different frames. While maintaining a constant total pulse width within a frame (corresponding to a constant Duty value), the average pulse width of the various high-level pulses across multiple frames tends to be equal. In the Sequential phase, since the pulse widths of the various high-level pulses are similar, pulse width dithering can be applied to each high-level pulse to make the average pulse width of all high-level pulses across multiple frames tend to be equal. Figure 8 In case 1 or case 2, the 4-frame loop when dither is on shows a pulse width skipping exchange in case 1 and a pulse width sequential rotation in case 2; while when dither is off, as shown in case 3... Figure 8 The four frames shown in the lower middle section maintain the pulse width of each high-level pulse unchanged. In the fill-up stage, the original high-level pulse is wider (called the first high-level pulse) while the newly added high-level pulse is narrower (called the second high-level pulse). Therefore, the pulse width of the first high-level pulse can be kept unchanged, and only the pulse width of the second high-level pulse is jittered.

[0050] It should be noted that, due to the aforementioned DBV drop phenomenon, from another perspective, when the pulse width of the high-level pulse of the EM_STV signal is (2+4n)H, (2+4n+1)H, or (2+4n+2)H, the actual output pulse width of the EM signal is equal (i.e., the duty is equal). For example... Figure 9 As shown, when the high-level pulse in the EM_STV signal has a pulse width of 2H, 3H, or 4H, the pulse width of the output EM signal is always 2H; Figure 10 As shown, when the high-level pulse in the EM_STV signal has a pulse width of 6H, 7H, or 8H, the output EM signal has a pulse width of 6H. Therefore, the 2 in the aforementioned basic pulse width value can also be replaced with 3 or 4, that is, the pulse width requirement is (a+4n)H, where a represents the number of basic pulse width rows, a = 2, 3, or 4. However, when calculating the Duty value or inversely calculating the pulse width from the Duty value, the part of a exceeding 2 should be ignored.

[0051] Example 2

[0052] This embodiment illustrates the duty adjustment method for EM_STV when the clock signal period is 2H. Again, taking the gradual adjustment from high DBV to low DBV as an example, the AC dimming demonstrated in this embodiment can be divided into a Fill-up stage and a Sequential stage. In some other embodiments, one of the two adjustment methods can also be used alone for duty adjustment of the EM_STV signal throughout the entire AC dimming stage.

[0053] like Figure 11 As shown, in the Fill-up stage, taking a Pulse count of 4 as an example, the initial pulse width of the first high-level pulse (frame_0) is (1+2n)H, where n is an integer. During the gradual adjustment process, first, a high-level pulse with the lowest pulse width is added at the time nodes corresponding to each newly added pulse. Then, at the time nodes corresponding to the third (#3), second (#2), and fourth (#4) high-level pulses within a frame, a high-level pulse with a basic pulse width of 1H is added (frame_0~3). Then, in the order of the high-level pulses #3, #2, and #4, the corresponding pulses are sequentially increased by 2H (after frame_3) until the pulse width of each high-level pulse reaches (1+2n)H. Figure 11In the illustration, the Duty value of the EM_STV signal decreases sequentially with each frame. Each frame corresponds to the EM_STV signal mapped to each DBV value in that stage. In actual dimming, the corresponding EM_STV signal can be generated according to the target DBV value to be adjusted. That is, the pulse width of the original pulse remains unchanged at (1+2n)H, and the sum of the required pulse widths is allocated to each newly added pulse, so that the pulse width of each pulse is in the form of (1+2k)H, where k is an integer (the remainder less than 2H after allocation can be discarded or padded to 2H for processing, so the accuracy of the pulse width sum adjustment, i.e., the adjustment step size, is 2H). At this time, the Duty value of the STV_EM signal is equal to the Duty value of the required EM signal output. In a preferred embodiment, the pulse widths corresponding to each newly added pulse do not differ from each other by more than 2H; in some other embodiments, they may differ by multiples of 2H, but the maximum pulse width does not exceed (1+2n)H. Since the pulse width adjustment step size is relatively small (1H) during the process of frame_0 to 3, frames_1 to 3 can also be combined into one adjustment step size. That is, after frame_0, the next DBV value directly corresponds to frame_3, skipping frame_1 and frame_2.

[0054] like Figure 12 As shown, in the Sequential stage, taking Pulse number 4 as an example, the pulse width of the initial 4 high-level pulses is (1+2n)H, where n is an integer. During the gradual adjustment process, frames_1 to 4, within one frame, the pulse width of each high-level pulse is increased by 2H in sequence according to the jump interval of #1, #3, #2, and #4. Figure 11 In the illustration, the Duty value of the EM_STV signal decreases sequentially with each frame. Each frame corresponds to the EM_STV signal mapped to each DBV value in that stage. In actual dimming, the corresponding EM_STV signal can be generated according to the target DBV value to be adjusted. That is, the sum of the required pulse width changes is distributed to each high-level pulse in units of 2H (the remainder less than 2H can be discarded or padded to 2H units for processing, so the adjustment step size of the sum of pulse widths is 2H). In a preferred embodiment, the pulse widths corresponding to each high-level pulse do not differ from each other by more than 2H; in other embodiments, they can differ by multiples of 2H. Compared with the prior art, this embodiment has a smoother AC dimming effect with multiple EM signals.

[0055] In a preferred embodiment, such as Figure 13As shown, during the stage where the DBV value remains constant, if the pulse widths of the various high-level pulses are not all equal, pulse width dithering can be enabled to further homogenize the display effect. In the Sequential stage, since the pulse widths of the various high-level pulses are similar, pulse width dithering can be applied to each high-level pulse to make the average pulse width of all high-level pulses in multiple frames tend to be equal. In the Fill-up stage, the original high-level pulses are wider (called the first high-level pulse) while the newly added high-level pulses are narrower (called the second high-level pulse). Therefore, the pulse width of the first high-level pulse can be kept constant, and pulse width dithering can be applied only to the second high-level pulse.

[0056] As can be seen from Embodiments 1 and 2, the core of the dimming method of the present invention is that, during AC dimming, if the EM_STV signal involves multiple high-level pulses within a frame, its pulse width is varied; or, if it involves changes from one high-level pulse to multiple high-level pulses within a frame, then each pulse width is set to the form (a+b·n)H, where b is the number of rows corresponding to the period of the clock signal used to modulate the EM signal, a is the number of rows corresponding to the basic pulse width, b / 2≤a≤b, and the portion of a exceeding b / 2 is not included in the total pulse width, and n is an integer. In actual dimming, the value of a can be kept constant, the change in the total pulse width is calculated, and b H values ​​are allocated to each high-level pulse as the smallest unit.

[0057] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0058] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A dimming method for an organic light-emitting display device, comprising generating an EM signal by modulation of an EM_STV signal and a clock signal, the EM signal being used to drive OLED cells; the EM_STV signal comprising multiple high-level pulses within one frame; the pulse width of the high-level pulse conforming to the form (a+b·n)H, where H is the duration corresponding to scanning a row of OLED cells, b is the period value of the clock signal in units of H, n is an integer, a is the base pulse width value of the high-level pulse in units of H; b / 2≤a≤b, and the portion of a exceeding b / 2 is not included in the total pulse width of the high-level pulses in each frame; when the DBV value changes, obtaining the change in the total pulse width of the high-level pulses in each frame based on the change in the DBV value, and changing the pulse width of one or more high-level pulses in the EM_STV signal based on the change in the total pulse width, using the period of the clock signal as the minimum unit.

2. The dimming method according to claim 1, characterized in that, The pulse widths of each high-level pulse within each frame differ from each other by no more than one clock cycle.

3. The dimming method according to claim 2, characterized in that, When the pulse widths of the various high-level pulses within a frame are not all equal, the high-level pulses are set to have a longer pulse width according to the skip interval method.

4. The dimming method according to claim 1, characterized in that, When the DBV value remains constant and the pulse widths of the various high-level pulses within a frame are not all equal, pulse width jitter is enabled to make the average pulse width of the various high-level pulses tend to be equal across multiple frames.

5. A dimming method for an organic light-emitting display device, comprising generating an EM signal by modulating an EM_STV signal and a clock signal, wherein the EM signal is used to drive OLED cells; the dimming method includes fill-up stage dimming; during the fill-up stage dimming, the EM_STV signal includes at least one first high-level pulse and at least one second high-level pulse; the pulse width and number of the first high-level pulses remain unchanged during the fill-up stage dimming; the pulse width of the first high-level pulse is (a+b·n0)H, where H is the duration corresponding to scanning one row of OLED cells, b is the period value of the clock signal in units of H, n0 is a preset positive integer, and a is the period value of the clock signal in units of H. The base pulse width value of the high-level pulse when used as a unit; b / 2≤a≤b, and the portion of a exceeding b / 2 is not included in the total pulse width of the high-level pulses in each frame; the pulse width of the second high-level pulse conforms to the form (a+b·k)H, where k is an integer and k≤n0; during dimming in the Fill-up stage, when the DBV value changes, the change in the total pulse width of the high-level pulses in each frame is obtained according to the change in the DBV value; according to the change in the total pulse width, the number of second high-level pulses with the base pulse width value is increased or decreased in the EM_STV signal, and / or, the pulse width of one or more second high-level pulses in the EM_STV signal is changed with the period of the clock signal as the smallest unit.

6. The dimming method according to claim 5, characterized in that, It also includes Sequential dimming; during Sequential dimming, the EM_STV signal includes multiple high-level pulses within one frame, and the pulse width of each high-level pulse conforms to the form (a+b·n)H, where n is an integer and n≥n0; during Sequential dimming, when the DBV value changes, the total change in the pulse width of the high-level pulses in each frame is obtained according to the change in the DBV value; based on the total change in the pulse width, the pulse width of one or more high-level pulses in the EM_STV signal is changed using the period of the clock signal as the smallest unit.

7. The dimming method according to claim 6, characterized in that, During the Fill-up dimming stage, the pulse widths of the second high-level pulses within each frame differ by no more than one clock signal cycle; during the Sequential dimming stage, the pulse widths of the high-level pulses within each frame differ by no more than one clock signal cycle.

8. The dimming method according to claim 7, characterized in that, During the fill-up dimming stage, when the pulse widths of the second high-level pulses within a frame are not all equal, the second high-level pulses are set to have a longer pulse width according to a skip interval. During the sequential dimming stage, when the pulse widths of the high-level pulses within a frame are not all equal, the high-level pulses are set to have a longer pulse width according to a skip interval.

9. The dimming method according to claim 5, characterized in that, When the DBV value remains constant and the pulse widths of the high-level pulses within a frame are not all equal, pulse width jitter is enabled to make the average pulse width of the high-level pulses in multiple frames tend to be equal.

10. The dimming method according to claim 5, characterized in that, During the fill-up dimming stage, when the DBV value remains unchanged and the pulse widths of the second high-level pulses within a frame are not all equal, pulse width jitter is enabled on the second high-level pulses to make the average pulse width of the second high-level pulses in multiple frames tend to be equal.

11. The dimming method according to claim 6, characterized in that, During the fill-up dimming stage, when the DBV value remains constant and the pulse widths of the second high-level pulses within a frame are not all equal, pulse width jitter is enabled on the second high-level pulses to make the average pulse width of the second high-level pulses in multiple frames tend to be equal; during the sequential dimming stage, when the DBV value remains constant and the pulse widths of the high-level pulses within a frame are not all equal, pulse width jitter is enabled to make the average pulse width of the high-level pulses in multiple frames tend to be equal.

12. The dimming method according to claim 5, characterized in that, The period of the clock signal is selected from 2H or 4H; the number of the first high-level pulses is 1.

Images