High frequency PWM dimming method and display device

Abstract

The present application provides a high-frequency PWM dimming method and display device, which relates to the field of display technology. Under a 90Hz refresh rate, the method uses a 120Hz refresh rate as the base frequency, 32 pulses as the reference pulse number, and a 3840Hz PWM specification as the target. The reference pulse number is set in the scanning area as the EM signal parameter for controlling the alternating flickering of the OLED screen; in the porch area, the non-integer result of the refresh rate 90Hz divided by the target PWM frequency 3840Hz is first obtained; then, the result is rounded, and the integer pulse number corresponding to the porch area is obtained according to the difference between the rounded result and the reference pulse number; finally, according to the target PWM frequency, the pulse number of the porch area and the reference pulse number, the actual refresh rate is reversely set, thereby realizing a dimming solution with a 3840Hz PWM specification at the 90Hz gear.

Description

[0001] This application is a divisional application. The application number of the original application is 202310611654.7, the application date of the original application is May 26, 2023, and the name of the original application is “High-frequency PWM dimming method and display device”. The entire contents of the original application are incorporated into this application by reference. Technical Field

[0002] The present application relates to the field of display technology, and in particular to a high-frequency PWM dimming method and a display device. Background Art

[0003] Since the popularization of organic electroluminescence display (OLED) screens in the mobile phone industry, the improvement in screen display effects has been obvious to all, such as high refresh rate, low blue light, high dynamic range imaging (HDR), etc., which have brought users a better screen viewing experience.

[0004] However, due to the light-emitting principle and characteristics of OLED current drive, when the corresponding current is very small at low brightness and low grayscale, it will lead to poor uniformity of picture color and brightness, serious problems of color deviation and mura. In order to solve this problem, one method currently adopted in the industry is: when the OLED screen is displayed at low brightness, pulse width modulation (PWM) is used to dim it; when the OLED screen is displayed at high brightness, direct current (DC) is used to dim it. Among them, the principle of PWM dimming is mainly: by constantly "lighting the screen-off-lighting the screen", the visual residual characteristics of the human eye are used to achieve the effect of making the user perceive that the screen brightness is reduced. However, since the essence of the PWM dimming method is to constantly alternate between light and dark, low-frequency PWM dimming may have a bad effect on the human eye when the user watches the screen for a long time. In view of the shortcomings of low-frequency PWM, some high-frequency PWM dimming solutions have been developed in the industry.

[0005] Generally speaking, the higher the PWM frequency, the less impact it has on the human eye. Therefore, how to obtain a higher frequency PWM dimming method as much as possible has become a very valuable research topic. Summary of the invention

[0006] The embodiment of the present application provides a high-frequency PWM dimming method, which reduces the impact of screen flicker on the human eye and improves the user's screen viewing experience by providing a dimming solution with a 3840Hz PWM specification.

[0007] The high-frequency PWM dimming method provided in the present application, at a refresh rate of 90Hz, first uses a refresh rate of 120Hz as the base frequency, 32pulses as the reference pulse number corresponding to the base frequency, and a 3840Hz PWM specification as the target, by setting the reference pulse number corresponding to the base frequency in the scanning area as the EM signal parameter for controlling the alternating flickering of the OLED screen; and in the porch area, first obtain the result of dividing the refresh rate 90Hz by the target PWM frequency 3840Hz, the result is 42.67pulses, which is a non-integer; then, round 42.67pulses to obtain 43pulses or 42pulses; then, according to the difference between the rounded result and the reference pulse number, obtain the integer pulse number corresponding to the porch area; finally, according to the target PWM frequency, the pulse number corresponding to the porch area and the reference pulse number, reversely set the actual refresh rate close to 90Hz, so as to achieve a dimming solution with a 3840Hz PWM specification even at the 90Hz gear. At the same time, it is also possible to apply the 3840Hz PWM dimming solution to the full frame rate range of almost all commonly used refresh rates, such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz. Specifically:

[0008] In a first aspect, a high-frequency PWM dimming method is provided, which is applied to a display device, comprising:

[0009] Setting the target refresh rate as the base frequency, and setting the number of EM signal pulses for brightness control corresponding to the base frequency as the reference pulse number;

[0010] In a scanning area of ​​a first refresh rate frame period, setting the number of EM signal pulses corresponding to the scanning area as the reference number of pulses, wherein the duration of the scanning area is the same as the duration of the base frequency frame period;

[0011] In a first porch area corresponding to a second refresh rate, the number of first EM signal pulses corresponding to the first porch area is set according to a target pulse width modulation PWM frequency, a PWM frequency corresponding to the scanning area, and the second refresh rate, wherein the second refresh rate is a refresh rate of the first refresh rate that cannot divide the base frequency evenly, and the number of first EM signal pulses is an integer;

[0012] Reversely obtain an actual refresh rate corresponding to the second refresh rate gear according to the target PWM frequency, the reference pulse number and the first EM signal pulse number;

[0013] At the second refresh rate level, refreshing the screen of the display device according to the actual refresh rate; and

[0014] The screen of the display device is turned on or off according to the reference pulse number corresponding to the scanning area of ​​the second refresh rate and the first EM signal pulse number corresponding to the first porch area.

[0015] In one implementation, the target refresh rate may be 120 Hz, and the reference pulse number (ie, reference pulse number, or reference EM signal parameter) may be 32 pulses.

[0016] In one implementation, the first refresh rate may refer to a commonly used refresh rate, such as 90 Hz, 60 Hz, 40 Hz, 30 Hz, 20 Hz, 10 Hz, etc. The first refresh rate may be different from the base frequency, and the first refresh rate may be less than the base frequency.

[0017] In one implementation, the frame period refers to the duration for which each frame of an image is displayed on the screen during a screen refresh process.

[0018] In combination with the first aspect, in some implementations of the first aspect, the first porch area corresponding to the second refresh rate sets the number of first EM signal pulses corresponding to the first porch area according to the target PWM frequency, the PWM frequency corresponding to the scanning area, and the second refresh rate, specifically including:

[0019] Obtaining a first result after dividing the target PWM frequency by the second refresh rate, where the first result is a non-integer;

[0020] According to the first result, obtaining a first integer closest to the first result;

[0021] The number of first EM signal pulses corresponding to the first porch area is set according to the first integer.

[0022] In combination with the first aspect, in some implementations of the first aspect, the first porch area corresponding to the second refresh rate sets the number of first EM signal pulses corresponding to the first porch area according to the target PWM frequency, the PWM frequency corresponding to the scanning area, and the second refresh rate, specifically including:

[0023] Acquire a first difference between the target PWM frequency and the PWM frequency corresponding to the scanning area;

[0024] Calculate a first result after dividing the first difference by the second refresh rate, where the first result is a non-integer;

[0025] According to the first result, obtaining a first integer closest to the first result;

[0026] The number of first EM signal pulses corresponding to the first porch area is set according to the first integer.

[0027] In combination with the first aspect, in some implementations of the first aspect, the target PWM frequency is 3840 Hz, the second refresh rate is 90 Hz, the base frequency is 120 Hz, the reference pulse number is 32 pulses, the first integer is 11 pulses, and the actual refresh rate is 89.3 Hz.

[0028] In combination with the first aspect, in some implementations of the first aspect, the first porch area corresponding to the second refresh rate sets the number of first EM signal pulses corresponding to the first porch area according to the target PWM frequency, the PWM frequency corresponding to the scanning area, and the second refresh rate, specifically including:

[0029] Obtaining a first result after dividing the target PWM frequency by the second refresh rate, where the first result is a non-integer;

[0030] According to the first result, obtaining a second integer that is second closest to the first result;

[0031] The number of first EM signal pulses corresponding to the first porch area is set according to the second integer.

[0032] In combination with the first aspect, in some implementations of the first aspect, the first porch area corresponding to the second refresh rate sets the number of first EM signal pulses corresponding to the first porch area according to the target PWM frequency, the PWM frequency corresponding to the scanning area, and the second refresh rate, specifically including:

[0033] Acquire a first difference between the target PWM frequency and the PWM frequency corresponding to the scanning area;

[0034] Calculate a first result after dividing the first difference by the second refresh rate, where the first result is a non-integer;

[0035] According to the first result, obtaining a second integer that is second closest to the first result;

[0036] The number of first EM signal pulses corresponding to the first porch area is set according to the second integer.

[0037] In combination with the first aspect, in certain implementations of the first aspect, the target PWM frequency is 3840 Hz, the second refresh rate is 90 Hz, the base frequency is 120 Hz, the reference pulse number is 32 pulses, the second integer is 10 pulses, and the actual refresh rate is 91.4 Hz.

[0038] In combination with the first aspect, in some implementations of the first aspect, reversely acquiring the actual refresh rate corresponding to the second refresh rate gear according to the target PWM frequency, the reference pulse number, and the first EM signal pulse number specifically includes:

[0039] Calculating the sum of the reference pulse number and the first EM signal pulse number to obtain a second result;

[0040] A third result obtained by dividing the target PWM frequency by the second result is obtained, where the third result is an actual refresh rate corresponding to the second refresh rate gear.

[0041] In combination with the first aspect, in some implementations of the first aspect, the actual refresh rate corresponding to the second refresh rate gear is obtained in the Long-V mode, and the method further includes:

[0042] In Long-H mode, the duration of scanning each row of pixels in the image during refresh is adjusted according to the actual refresh rate, and the adjusted first row scanning duration is obtained, wherein the first row scanning duration causes the refresh rate corresponding to the refresh to be adjusted to the second refresh rate.

[0043] According to the method provided by the present implementation, by adjusting the scanning time of each row of pixels at the actual refresh rate in Long-H mode to obtain an accurate 90Hz refresh rate, a dimming scheme with a 3840Hz PWM specification (actually a 3870Hz PWM specification) can be achieved at accurate 90Hz, thereby realizing the application of the dimming scheme with a 3840Hz PWM specification to the full frame rate range of almost commonly used refresh rates, such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0044] In combination with the first aspect, in some implementations of the first aspect, the method further includes:

[0045] In a second porch area corresponding to a third refresh rate, replicating the reference pulse number once or multiple times for the EM signal, wherein the third refresh rate is a refresh rate of the first refresh rate that can divide the base frequency;

[0046] At a third refresh rate, refreshing the screen of the display device according to the third refresh rate; and,

[0047] The screen of the display device is turned on or off according to the reference pulse number corresponding to the scanning area of ​​the third refresh rate and the copied reference pulse number corresponding to the second porch area.

[0048] In combination with the first aspect, in some implementations of the first aspect, the method further includes:

[0049] The operation of refreshing the screen of the display device is performed only in the scanning area.

[0050] In a second aspect, a display device is provided, including:

[0051] Organic light-emitting semiconductor OLED screen;

[0052] one or more processors;

[0053] one or more memories;

[0054] The one or more memories store one or more computer programs, and the one or more computer programs include instructions. When the instructions are executed by the one or more processors, the display device executes the method as described in any one of the first aspects above.

[0055] In a third aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer-executable program instructions, and when the computer-executable program instructions are executed on a computer, the computer executes the method as described in any one of the above-mentioned first aspects.

[0056] In a fourth aspect, a computer program product is provided, the computer program product comprising a computer program code, and when the computer program code is run on a computer, the computer is caused to execute the method as described in any implementation manner of the above-mentioned first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A schematic diagram of independently setting the number of pulses for a 120 Hz refresh rate under a 2160 Hz PWM specification provided in an embodiment of the present application.

[0058] Figure 2 A schematic diagram of the structure of an OLED pixel driving circuit provided in an embodiment of the present application.

[0059] Figure 3 A schematic diagram of the timing principle in LongV mode and Long-H mode with a 90Hz refresh rate provided in an embodiment of the present application.

[0060] Figure 4 A schematic diagram of the timing principle in LongV mode with a 90Hz refresh rate provided in an embodiment of the present application.

[0061] Figure 5 A schematic diagram of a dimming solution of 3840Hz PWM corresponding to a refresh rate of 89.3Hz provided in an embodiment of the present application.

[0062] Figure 6 A schematic diagram of a dimming solution of 3840Hz PWM corresponding to a 91.4Hz refresh rate provided in an embodiment of the present application.

[0063] Figure 7A schematic diagram of a Long-V mode provided in an embodiment of the present application, after determining that the refresh rate set in reverse is 89.3 Hz, and then modifying the row scanning duration based on 89.3 Hz.

[0064] Figure 8 A schematic diagram of a Long-V mode provided in an embodiment of the present application after determining that the reverse set refresh rate is 91.4 Hz, and then modifying the row scanning duration based on 91.4 Hz.

[0065] Fig. 9 A schematic flowchart of a high-frequency PWM dimming method provided in an embodiment of the present application.

[0066] Fig.10 A schematic flowchart of another high-frequency PWM dimming method provided in an embodiment of the present application.

[0067] Fig.11 A schematic diagram of the structure of a display device 100 provided in an embodiment of the present application.

[0068] Fig.12 A software structure block diagram of a display device 100 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0069] It should be noted that the terms used in the implementation method part of the embodiments of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in this article is only a description of the association relationship of associated obstacles, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more than two, "at least one" and "one or more" mean one, two or more than two.

[0070] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, it is defined that the "first" and "second" features may explicitly or implicitly include one or more of the features.

[0071] References to "one embodiment" or "some embodiments" etc. described in this specification mean that a particular feature, structure or characteristic described in conjunction with the embodiment is included in one or more embodiments of the present application. Thus, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. appearing at different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in another way. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in another way.

[0072] The technical solution of the present application is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0073] In view of the shortcomings of the traditional low-frequency PWM dimming solution, the industry has developed a 2160Hz high-frequency PWM (hereinafter referred to as 2160Hz PWM specification) dimming solution. When using the 2160Hz PWM specification dimming, in order to achieve a consistent PWM frequency (2160Hz) at different refresh rates, the pulse number of the brightness control (emission, EM) signal needs to be accurately set.

[0074] For example, in order to achieve the 2160Hz PWM specification, two main methods can be used for setting: Method (1), separately set the number of pulses corresponding to different refresh rates. Method (2), set a refresh rate as the base frequency (such as 120Hz), and set the number of pulses corresponding to the base frequency as the reference pulse number (such as 18 pulses at 120Hz), and then expand the number of pulses corresponding to other refresh rates by n times according to the reference pulse number, and / or expand the gate driver on array (GOA) signal parameters by n times according to the reference pulse number.

[0075] It should be noted that the pulse number mentioned in the embodiment of the present application may refer to the number of pulses corresponding to the EM signal used to light up or turn off the screen in one frame. In the embodiment of the present application, the pulse number can also be described as the EM drive pulse number or the EM signal parameter. It should also be noted that the PWM frequency is numerically equal to the product of the refresh rate and the EM pulse number, where the units of the PWM frequency and the refresh rate are both Hz.

[0076] For method (1) above, see Figure 1To achieve the 2160Hz PWM specification, for the 120Hz refresh rate, the pulse number can be independently set to 18 pulses (that is, the result of 120Hz divided by 2160Hz). In this case, the pulse waveform of the 2160Hz PWM can be found in Figure 1 The waveform corresponding to 18 pulse-PWM in the figure. For a 60Hz refresh rate, the corresponding pulse number can be independently set to 36 pulses (that is, the result after 60Hz is divided by 2160Hz). In this case, the pulse waveform of 2160Hz PWM can be found in Figure 1 The waveform corresponding to 36 pulse-PWM in . For a 90Hz refresh rate, the corresponding pulse number can be independently set to 24 pulses (that is, the result after 90Hz is divided by 2160Hz). In this case, the pulse waveform of 2160Hz PWM can be seen in Figure 1 The waveform corresponding to 36pulse-PWM.

[0077] In the above method (1), by separately setting the corresponding pulse number for different refresh rates (120 Hz, 60 Hz, 90 Hz), dimming can be achieved at different refresh rates with a 2160 Hz PWM specification.

[0078] For method (2) above, please continue to refer to Figure 1 To achieve the 2160Hz PWM specification, set the 120Hz refresh rate as the base frequency, and set the 18 pulses corresponding to the base frequency as the reference pulse number. Then, at 60Hz and 90Hz refresh rates, according to the multiple relationship between the refresh rate and the base frequency, set the pulse numbers corresponding to the 60Hz and 90Hz refresh rates based on the reference pulse number. Specifically:

[0079] For a 60Hz refresh rate, since 60Hz is divided by 120Hz to get 2, the pulse number corresponding to the 60Hz refresh rate can be the base pulse number after 2 times of expansion. At this time, under a 60Hz refresh rate, the base pulse number (i.e. 18 pulses) can be directly copied in the scanning area for dimming, and the base pulse number can be completely repeated once in the porch area (or blanking area) after the scanning is completed for dimming.

[0080] For the 90Hz refresh rate, since 90Hz cannot divide 120Hz, and the pulse number needs to be an integer, the pulse number corresponding to the 90Hz refresh rate cannot be obtained by expanding the base pulse number by an integer multiple. At this time, at a 90Hz refresh rate, although the base pulse number (that is, 18 pulses) can be set to be directly copied in the scanning area for dimming, the base pulse number cannot be completely copied in the porch area after the scan is completed. In this regard, a separate set of pulse numbers can be set for the 90Hz refresh rate, such as 24 pulses, and its pulse width can be different from that of 120Hz or 60Hz.

[0081] In order to further enhance the user's visual experience and make the screen of the display device more eye-friendly, this application proposes a 3840Hz high-frequency PWM (hereinafter referred to as 3840Hz PWM specification) dimming solution. Combined with the above-mentioned setting method of the 2160Hz PWM specification, if you want to achieve the 3840Hz PWM specification, you can also try to use two methods: method (1), set the number of pulses corresponding to different refresh rates separately, such as setting the number of pulses corresponding to the 120Hz refresh rate to 32, and setting the number of pulses corresponding to the 60Hz refresh rate to 64; method (2), set a refresh rate as the base frequency (such as 120Hz), and set the number of pulses corresponding to the base frequency as the reference pulse number (such as 32 pulses of 120Hz), and then expand the number of pulses corresponding to other refresh rates by n times according to the reference pulse number, and / or expand the GOA signal parameters by n times according to the reference pulse number. For example, at a refresh rate of 60Hz, the corresponding pulse number can be expanded by 2 times according to the benchmark pulse number, that is, the benchmark pulse number is completely copied once in the scanning area and the porch area, and the pulse number in each area is 32.

[0082] However, it is worth noting that if the target PWM frequency is 3840Hz, then for the 90Hz refresh rate, the above-mentioned 2160Hz PWM specification setting method cannot be directly reused. On the one hand, if the number of pulses corresponding to the 90Hz refresh rate is set separately, then the set number of pulses is approximately 43pulses (that is, the result of dividing 3840Hz by 90Hz), but the current driver chip (intergrated circuit, IC) usually only supports independent settings of no more than 32pulses due to specification limitations, so this method cannot achieve the 3840Hz PWM specification at a 90Hz refresh rate. On the other hand, since 90Hz cannot be divided into 120Hz, the base pulse number (that is, 32pulses of 120Hz) cannot be completely copied in the porch area, so this method cannot achieve the 3840Hz PWM specification at a 90Hz refresh rate.

[0083] 90Hz is a common refresh rate for display devices such as mobile phones and tablets, and the above problems have resulted in the 3840Hz PWM dimming solution not being able to be applied to a 90Hz refresh rate. In other words, the 3840Hz PWM specification cannot cover the commonly used full frame rate range, which will greatly affect the user experience of the display device.

[0084] In view of this, an embodiment of the present application provides a method for high-frequency PWM dimming. At a refresh rate of 90 Hz, the method first uses a refresh rate of 120 Hz as the base frequency, uses 32 pulses as the reference pulse number corresponding to the base frequency, and uses a 3840 Hz PWM specification as a target. Then, a non-integer result after 3840 Hz is obtained after dividing 90 Hz, and the non-integer result is rounded to obtain a rounded result of 43 or 42; thereafter, the pulse number of the porch area at a refresh rate of 90 Hz is obtained according to the difference between the rounded result and the reference pulse number, and 91.4 Hz or 89.3 Hz close to 90 Hz is obtained in reverse according to the target PWM frequency and the rounded result (or the sum of the reference pulse number and the pulse number of the porch area) to be regarded as (or set to) the 90 Hz gear, thereby achieving 3840 Hz at the 90 Hz refresh rate gear. PWM specifications, thereby achieving a 3840Hz PWM dimming solution with a full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0085] In order to better understand the high-frequency PWM dimming method provided in the embodiment of the present application, the principle of dimming the OLED screen using PWM is introduced below in conjunction with the accompanying drawings.

[0086] First of all, it should be noted that OLED is a current-type organic light-emitting device, which is a phenomenon of luminescence caused by the injection and recombination of carriers, and the luminescence intensity is proportional to the injected current. Under the action of the electric field, the holes generated by the anode and the electrons generated by the cathode will move, and are injected into the hole transport layer and the electron transport layer respectively, and migrate to the light-emitting layer. When the two meet in the light-emitting layer, energy excitons are generated, which excite the light-emitting molecules and finally produce visible light. In other words, the OLED panel is a self-luminous product. It does not require a backlight, and it can emit light by itself. The display can be completed by controlling the brightness of the light-emitting pixels to form different images.

[0087] OLED mainly consists of four parts, namely driver IC, battery, display area and pixel driver circuit. Among them, driver IC is the core part of OLED display, which controls the switch and brightness of the display screen; battery is used to power OLED; display area is composed of OLED screen, which can be divided into several pixels; pixel driver circuit is mainly used to transmit signals between driver IC and display area.

[0088] The pixel driving circuit in the OLED may include a gate on array (GOA) circuit and an EM circuit on an array substrate. These two circuits may respectively perform different display functions under the control of a driver IC.

[0089] The GOA circuit is a repeated circuit unit located on both sides of the OLED panel, which is controlled by the driver IC to transmit the GOA signal. The GOA signal is a signal used to control the gate scanning, which can control the pixel points in the OLED screen (or surface) to open row by row, and write the display signal into the pixel capacitor in the screen row by row. Through the timing configuration, the GOA signal can also control the scanning time of each row of pixels and the duration of the porch area corresponding to each frame of the image.

[0090] The EM circuit is controlled by the driver IC to transmit the EM signal. The EM signal is used to control the lighting of the OLED. For each pixel in the OLED screen, after charging is completed, the thin film transistor (TFT) analog switch T3 in the driver circuit will be in the default on state. At this time, the EM signal controls T3 to perform the "on-off-on" operation according to the set frequency, so that the pixels in the OLED screen can be synchronously lit and turned off (that is, the pixels switch between the "lit-off-lit" states accordingly).

[0091] It should be noted that it is precisely because PWM dimming can make pixels light up and off alternately that users can perceive that the brightness of the OLED screen is reduced. This feature is also one of the obvious differences between PWM dimming and DC dimming. During DC dimming, the EM signal will always indicate that T3 is in the on state, and the pixels will not light up and off alternately.

[0092] For example, Figure 2 , which is a schematic diagram of the structure of an OLED pixel driving circuit provided in an embodiment of the present application.

[0093] The pixel driving circuit is used to drive the light emitting element OLED. Figure 2 As shown, the pixel driving circuit provided in the embodiment of the present application includes:

[0094] The EM signal terminal is used to provide a light-emitting control signal (EM signal).

[0095] The first switch unit 310 has an input terminal connected to the second power line ELVDD, a control terminal connected to the EM signal terminal, and an output terminal connected to the first intermediate node q.

[0096] The driving unit 320 has an input end connected to the first intermediate node q, a control end connected to the third intermediate node r, an output end connected to one end of the light emitting element OLED, and the other end of the OLED is connected to the first power line ELVSS. Exemplarily, the driving unit 320 may specifically include a TFTT3 tube and another thin film transistor switch unit T4. For each pixel, after charging is completed, the driving TFT T3 tube is always in the on state. At this time, the lighting or extinguishing of the OLED screen is controlled by the EM signal, and the OLED screen is in an alternating state of lighting (actually, the pixels in the OLED panel are alternately lit, that is, the pixels are correspondingly switched between the "lit-off-lit" state). For example, the so-called DC dimming means that the EM is always in the on state (low level); PWM dimming means that the EM is switched on-off-on at a set frequency to adjust the pixel brightness.

[0097] The third switch unit 330 has an input end connected to the third intermediate node r, a control end connected to the third-stage scan line S(n+2) (or the Reset line), and an output end connected to the second intermediate node p.

[0098] The second switch unit 340 has an input terminal connected to the reference signal line Ref, a control terminal connected to the second-stage scan signal line S(n+1), and an output terminal connected to the second intermediate node p.

[0099] The charging control unit 350 has a first input terminal connected to the reference signal line Ref, a second input terminal connected to the data line Data, a control terminal connected to the first-level scanning signal S(n) (or the Reset line), a first output terminal connected to the second intermediate node p, and a second output terminal connected to the third intermediate node r.

[0100] The storage unit 360 (ie, the capacitor Cst) has a first end connected to the first intermediate node q, and a second end connected to the third intermediate node r.

[0101] In the first operation phase of the pixel driving circuit, under the control of the EM signal outputted from the EM signal terminal, the first switch unit 310 conducts the second power line ELVDD and the first intermediate node q. Under the control of the first scanning signal Vs(n) outputted from the first-stage scanning signal line S(n), the charging control unit 350 conducts the reference signal line Ref and the second intermediate node p, thereby charging the storage unit 360 (Cst) connected to the first intermediate node q and the second intermediate node p, so that the storage unit 360 (Cst) stores the voltage V=V ELDD-V Ref , where V ELDD represents the potential of the second power supply line ELVDD, V Ref Indicates the potential of the reference signal line Ref.

[0102] In the second operation phase of the pixel driving circuit, under the control of the second level scanning signal Vs(n+1) outputted from the second level scanning signal line S(n+1), the second switch unit 340 conducts the reference signal line Ref and the second intermediate node p. At the same time, due to the EM signal, the first switch unit 310 is turned off, and the first storage unit 360 is self-discharged through the driving unit 320, so that the first storage unit 360 stores a charging voltage related to the data voltage and the threshold voltage of the driving unit.

[0103] In the third operation phase of the pixel driving circuit, under the control of the third scanning signal Vs(n+2) output by the third scanning signal line S(n+2) (i.e., the Gate line), the third switch unit 330 conducts the third intermediate node r and the second intermediate node p, so that the second storage unit 370 ( Figure 2 The second storage unit (not shown) is discharged, that is, the voltage difference across the second storage unit becomes zero.

[0104] In the driving stage of the pixel driving circuit, under the control of the EM signal output by the EM signal line, the first switch unit 310 turns on the second power supply point ELVDD and the first intermediate node q, so that the voltage difference between the control end and the input end of the driving unit 320 is equal to the voltage stored in the first storage unit and the second storage unit. Since the voltage difference across the second storage unit is zero, the driving current provided by the driving unit to the light-emitting element OLED has nothing to do with its threshold voltage.

[0105] It should be understood that the EM circuit is used to transmit EM signals under the control of the driver IC. The EM signal is used to control the pixels in the OLED screen to light up or go out. It is precisely because of the characteristic of PWM dimming that the pixels can be alternately lit and turned off that users can perceive that the brightness of the OLED screen is reduced. This characteristic is also one of the obvious differences between PWM dimming and DC dimming. During DC dimming, the EM signal will always indicate that T3 is in the on state, and the pixels will not be in the alternating state of light and off.

[0106] It should also be noted that for the refresh rate, the screen displays static images frame by frame, and they are refreshed continuously to obtain dynamic images. Within 1 second, the number of times the screen refreshes the static image indicates its refresh rate. Usually, the refresh rate of ordinary display devices is 60Hz, and the screens of many display devices have been adapted to 90Hz or even 120Hz refresh rates. The most intuitive feeling of a high refresh rate is that the picture is smoother.

[0107] When the image is refreshed, a frame of the image will include many pixels. For example, for an image including more than 400,000 pixels, it is obviously impossible to use more than 400,000 channels to transmit the information of each pixel at the same time. Therefore, image refresh actually converts the information of each pixel in the image into an electrical signal in a certain spatial order (such as each row from left to right, and then from top to bottom), and transmits it in chronological order. In this way, the changes of the image over space and time can be converted into the changes of the electrical signal over time. Among them, the signal that controls the scanning of the pixel here is also the GOA signal. Through the timing configuration, the driver IC in the display device can also control the scanning time of each row and the porch length of each frame through the GOA signal.

[0108] The above describes the pixel driving process and image refresh principle involved in the PWM dimming process in combination with the pixel driving circuit. The following describes the specific implementation process of the high-frequency PWM dimming method provided in the embodiment of the present application in combination with the accompanying drawings.

[0109] It should be noted that the high-frequency PWM dimming method provided in the embodiment of the present application can adjust the frame rate through the inter-frame touch drive (long vertical, Long-V) mode and the inter-frame touch drive (long horizontal, Long-H) mode. Figure 3 As shown, it is a schematic diagram of the timing principle of the LongV mode and Long-H mode with a 90Hz refresh rate provided in an embodiment of the present application.

[0110] like Figure 3 As shown, at a refresh rate of 120 (base frequency), the OLED screen can be refreshed 120 times in 1s, that is, the frame period corresponding to each frame of the image is about 8.33ms. In each frame period, the driver IC will scan the pixels in the OLED screen from left to right and from top to bottom row by row through the GOA signal (i.e., gate signal), and display the pixels of the entire OLED screen one by one in sequence. For example, taking a resolution of 1080×2800 as an example, the driver IC needs to scan 2800 rows of pixels in a frame period, then in a frame period, the driver IC will start from the first row and scan the pixels from left to right, and then scan the second row, the third row, ..., the 2800th row in the same way to obtain each pixel of the frame image, and then scan in the next frame period.

[0111] The refresh process of 90Hz refresh rate is similar to that of 120Hz refresh rate, which is also the way of scanning pixels line by line as described above. In the process of scanning the image pixels, the driver IC can also output the vertical synchronizing signal (VSYNC) and the horizontal synchronizing signal (HSYNC) (HSYNC signal is in Figure 3 (not shown). The VSYNC signal is used to control the start of scanning pixels of a frame of image; the HSYNC signal is used to control the start of scanning a row of pixels in a frame of image.

[0112] Combination Figure 3 and Figure 4 As shown, in the method provided in the embodiment of the present application, two pixel scanning modes can be adopted at a refresh rate of 90 Hz, namely Figure 3 The 90Hz Long-V mode and 90Hz Long-H mode are shown. Among them, in the 90Hz Long-V mode, there is a short VFP duration before a VSYNC signal, and there is a short VBP duration after the VSYNC signal. The actual start of scanning a frame of image occurs after the VBP duration. That is to say, taking VSYNC as the reference, the short duration before VSYNC is VFP, and the short duration after VSYNC is VBP, and these durations are all included in the EM duration. Specifically, before the VSYNC signal, the VFP duration will be waited at the end of the frame period of the previous frame; after the VSYNC signal, the VBP duration will be waited at the beginning of the frame period of the next frame, and then under the control of the GOA signal, the pixels of the next frame will be actually scanned.

[0113] The data signal covers the duration of the actual scanning of the image pixels, while the EM signal covers the scanning area and the porch area, that is, the EM signal covers the entire frame period.

[0114] The duration of the porch area within the frame period can be regarded as the sum of the VBP duration, the VFP duration and the VSYNC signal duration. Optionally, considering that the VSYNC signal duration is extremely short, in some cases, the duration of the porch area can also be regarded as the sum of the VBP duration and the VFP duration, while ignoring the duration of the VSYNC signal.

[0115] It should be noted that, for ease of understanding, the accompanying drawings corresponding to the embodiments of the present application draw the VSYNC signal pulse waveform more clearly, but in actual applications, the duration corresponding to the VSYNC signal is extremely short. In some cases, it can be ignored or not when determining the porch area as needed.

[0116] It should also be noted that the accompanying drawings corresponding to the embodiments of the present application are only for illustration, wherein the number of pulses and refresh rate of the EM signal are not reflected in accurate numerical values, but are only for schematic display, and therefore the refresh rate, number of pulses of the EM signal, etc. shown in the accompanying drawings are not intended to limit the embodiments of the present application. In addition, the durations shown in the accompanying drawings corresponding to the embodiments of the present application (including the scanning area durations at 120Hz and 90Hz refresh rates, the porch area durations at 120Hz and 90Hz refresh rates, the durations corresponding to the data signal and the EM (PWM) signal, and the scanning duration and porch duration in the 90Hz Long-H mode, etc.) are all examples and do not constitute specific limitations on the embodiments of the present application.

[0117] The driver IC can also control the lighting or extinguishing of the OLED panel through the EM signal, thereby controlling the brightness of the pixel points of the frame image (or the screen display brightness). Specifically, if the frequency of the PWM dimming scheme is 3840Hz, then the number of pulses corresponding to the EM signal in the frame period is 32 (that is, the result after 120Hz is divided by 3840Hz). In other words, at a refresh rate of 120Hz, within a frame period, the OLED screen will alternate between lighting and extinguishing at a frequency of 32pulse / 1s.

[0118] At a refresh rate of 90Hz, the OLED screen can be refreshed 90 times in 1s, that is, the frame period corresponding to each frame of the image is about 11.1ms. In each frame period, the driver IC will scan the pixels in the OLED screen from left to right and from top to bottom row by row through the GOA signal, sequentially displaying the pixels of the entire OLED screen one by one, and then scan in the next frame period. In the process of scanning the image pixels, the driver IC can first control the lighting or extinguishing of the OLED screen according to the reference pulse number (that is, 32 pulses) of the base frequency (120Hz). Since the pixels to be scanned are the same regardless of the 90Hz or 120Hz refresh rate, at a 90Hz refresh rate, only the same frame period as 120Hz (about 8.33ms, 8.33ms is used below to represent the frame period of 120Hz refresh rate) is needed to scan the pixels in the OLED screen. The remaining frame period (that is, the frame period corresponding to the 120Hz refresh rate minus the frame period corresponding to 90Hz, which is about 0.28ms) is the porch area. In this porch area, the driver IC will no longer continue to scan the pixels of the frame image, but in order to ensure the brightness of the OLED screen, the OLED screen still needs to be alternately lit and extinguished in the porch area, otherwise a black screen may appear.

[0119] So how to determine the number of pulses in the porch area at a refresh rate of 90Hz? The embodiment of the present application can calculate the number of pulses in the following way: first, obtain the result after dividing the target PWM frequency by 90Hz, and the result can be obtained by the following formula (1-1); then, according to the result, take the two closest integers, that is, take the closest integer and / or the second closest integer, and the rounded result is 43Hz or 42Hz; then, obtain the difference between the integer taken and the reference pulse number, which is the pulse number set for the porch area at a refresh rate of 90Hz, where the difference can be obtained by the following formula (1-2) or formula (1-3).

[0120] 3840Hz÷90Hz≈42.67pulse(1-1)

[0121] 43-32=11pulse(1-2)

[0122] 42-32=10pulse(1-3)

[0123] After obtaining the pulse number corresponding to the porch area, the actual refresh rate can be reversed, and then the refresh rate can be set in reverse so that the PWM frequency reaches 3840Hz.

[0124] Optionally, the embodiment of the present application can also calculate the pulse number in the following way: First, since the OLED has been alternately turned on and off according to 32 pulses within 8.33ms, it is still 960Hz away from the target 3840Hz PWM specification (this result can be calculated by the following formula (1-4)), then theoretically the pulse number that needs to be set in the porch area can be 10.67pulse (this result can be calculated by the following formula (1-5)). However, considering that the pulse number needs to be an integer, the two integers closest to 10.67pulse can be taken: 10pulse and 11pulse.

[0125] 3840Hz-90Hz×32pulse=960Hz(1-4)

[0126] 960Hz÷90Hz≈10.67pulse(1-5)

[0127] The porch area corresponding to the 90 Hz refresh rate is set to 10 pulses or 11 pulses respectively, and the total number of pulses in one frame period of the 90 Hz refresh rate is obtained to be 42 pulses or 43 pulses respectively. The results can be obtained according to the following formulas (1-6) and (1-7) respectively.

[0128] 32pulse+10pulse=42pulse(1-6)

[0129] 32pulse+11pulse=43pulse(1-7)

[0130] After obtaining the pulse number corresponding to the porch area, the actual refresh rate can be inferred, and then the refresh rate can be reversed to make the PWM frequency reach 3840Hz. It should be understood that the refresh rate results of the reverse setting will be different if the set pulse number is different. Therefore, based on different pulse numbers, the embodiments of the present application provide a variety of solutions for reversely inferring the refresh rate. The following is a detailed introduction to some of the solutions in conjunction with the accompanying drawings.

[0131] Solution 1: The EM signal parameters are set to 43 pulses, that is, the 90Hz scan area is set to the same base pulse number (32 pulses) as the 120Hz scan area. After scanning 32 pulses, 11 pulses are repeated in the porch area.

[0132] For ease of understanding, the following embodiments all include a situation corresponding to a 60 Hz refresh rate for comparison.

[0133] First, for the 60Hz refresh rate, since 60Hz can be divided into 120Hz, when the 3840Hz PWM specification is used as the target, the pulse number corresponding to the 60Hz refresh rate can be doubled based on the reference pulse number (32pulse). Specifically, within the frame period of the 60Hz refresh rate, the OLED is first controlled to light up and turn off alternately in the scanning area according to the same 32pulse number as 120Hz. When the scanning area ends, the 32pulse number of 120Hz is completely copied in the porch area.

[0134] It should be noted that the end of the scanning area indicates that the driver IC has completed scanning the pixels of the current frame image through the GOA signal. Therefore, in the porch area corresponding to the 60Hz refresh rate, there is no need to perform repeated scanning operations on the pixels of the frame image, but the EM signal still needs to continue to control the OLED to light up and off alternately according to the set 32pulse.

[0135] Optionally, for a 60Hz refresh rate, if the driver IC can support an independent setting higher than 32 pulses, the EM signal parameter corresponding to the 60Hz refresh rate can be set to 64 pulses (i.e., the result after 60Hz is divided by 3840Hz). Alternatively, if the driver IC does not support an independent setting higher than 32 pulses, the result 64 pulses after 60Hz is divided by 3840Hz can be divided into two 32 pulses, and then the OLED is controlled to light up and turn off alternately in the scanning area and the porch area according to 32 pulses respectively.

[0136] For a 90Hz refresh rate, when the corresponding EM signal parameter is set to 43pulse, the actual refresh rate can be inferred to be 89.3Hz with a 3840Hz PWM specification as the target. This result can be obtained according to the following formula (1-8).

[0137] 3840Hz÷43pulse≈89.30Hz(1-8)

[0138] Afterwards, the driver IC is reversely set to refresh the OLED screen at a refresh rate of 89.30Hz (89.3Hz), and the EM signals of 32pulse in the scanning area and 11pulse in the porch area are used to control the OLED screen to alternately flicker, thereby realizing a dimming solution with a 3840Hz PWM specification.

[0139] For example, at a refresh rate of 89.3 Hz, the corresponding 3840 Hz PWM dimming scheme diagram can be found in Figure 5 .

[0140] In some embodiments, for ease of understanding and comparison, the frame period corresponding to the 89.3 Hz refresh rate (about 11.20 ms) can be regarded as two parts, the first part is the same as the duration of the frame period corresponding to the 120 Hz refresh rate (about 8.33 ms), and the second part is the remaining duration of the frame period corresponding to the 89.3 Hz refresh rate (about 2.87 ms). It is easy to understand that the first part is also the scanning area, and the second part is also the porch area.

[0141] In specific implementation, the display device can control the OLED to light up and turn off alternately in the scanning area according to the reference EM signal parameter 32 pulses. After completing 32 pulses in about 8.33ms, the OLED is controlled to light up and turn off alternately according to the separately set 11 pulse EM signal parameter within the remaining porch area length (about 2.87ms) of the frame period corresponding to the 89.3Hz refresh rate.

[0142] It should be noted that the end of the scanning area indicates that the driver IC has completed scanning the pixels of the current frame image through the GOA signal. Therefore, in the porch area corresponding to the 89.3Hz refresh rate, there is no need to perform repeated scanning operations on the pixels of the frame image, but the EM signal still needs to continue to control the OLED to light up and off alternately according to the set 11pulse.

[0143] According to the high-frequency PWM dimming solution provided in the embodiment of the present application, at a refresh rate of 90 Hz, firstly, a refresh rate of 120 Hz is used as the base frequency, 32 pulses are used as the reference pulse number corresponding to the base frequency, and a 3840 Hz PWM specification is used as the target. The reference pulse number corresponding to the base frequency is set in the scanning area as the EM signal parameter for controlling the alternating flickering of the OLED screen; and in the porch area, firstly, the result of dividing the target PWM frequency 3840 Hz by the refresh rate 90 Hz is obtained, and the result is 42.67 pulses, which is a non-integer; then, 42.67 pulses are rounded to obtain 43 pulses or 42 pulses; then, according to the difference between the rounded result and the reference pulse number, the integer pulse number corresponding to the porch area is obtained; finally, according to the target PWM frequency, the pulse number corresponding to the porch area and the reference pulse number, the actual refresh rate close to 90 Hz is reversely set, so as to achieve a dimming solution with a 3840 Hz PWM specification even at the 90 Hz gear. At the same time, it is also possible to apply the 3840Hz PWM specification dimming solution to the full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0144] Solution 2: The EM signal parameters are set to 42 pulses, that is, the 90Hz scan area sets the same base pulse number (32 pulses) as the 120Hz scan area. After scanning 32 pulses, 10 pulses are repeated in the porch area.

[0145] First, for the 60Hz refresh rate, since 60Hz can be divided into 120Hz, when the 3840Hz PWM specification is used as the target, the pulse number corresponding to the 60Hz refresh rate can be doubled based on the reference pulse number (32pulse). Specifically, within the frame period, the OLED is first controlled to alternately light up and off according to the same reference pulse number as 120Hz. After 32pulses are completed in the scanning area, the reference pulse number of 120Hz is completely copied in the porch area.

[0146] It should be noted that the end of the scanning area indicates that the driver IC has completed scanning the pixels of the current frame image through the GOA signal. Therefore, in the porch area corresponding to the 60Hz refresh rate, there is no need to perform repeated scanning operations on the pixels of the frame image, but the EM signal still needs to continue to control the OLED to light up and off alternately according to the set 32pulse.

[0147] Optionally, for a 60Hz refresh rate, if the driver IC can support an independent setting higher than 32 pulses, the EM signal parameter corresponding to the 60Hz refresh rate can be set to 64 pulses (that is, the result after 60Hz is divided by 3840Hz). Alternatively, if the driver IC does not support an independent setting higher than 32 pulses, the 64 pulses can be divided into two 32 pulses according to the result after 60Hz is divided by 3840Hz, and then the OLED is controlled to light up and turn off alternately in the scanning area and the porch area according to 32 pulses.

[0148] For a 90 Hz refresh rate, when the corresponding EM signal parameter is set to 42 pulses, the 3840 Hz PWM specification can be used as the target, and the actual refresh rate can be inferred to be 91.4 Hz. This result can be obtained according to the following formula (1-9).

[0149] 3840Hz÷42pulse≈91.43Hz(1-9)

[0150] After that, reversely set the driver IC to refresh the OLED screen at a refresh rate of 91.43Hz (or 91.4Hz), and use the EM signals of 32pulse in the scanning area and 10pulse in the porch area to control the OLED screen to alternately flicker, so as to achieve a dimming solution with a 3840Hz PWM specification.

[0151] For example, at a refresh rate of 91.4 Hz, the corresponding 3840 Hz PWM dimming scheme diagram can be found in Figure 6 .

[0152] In some embodiments, for ease of understanding and comparison, the frame period corresponding to the 91.4 Hz refresh rate (about 10.94 ms) can be regarded as two parts, the first part is the same as the length of the frame period corresponding to the 120 Hz refresh rate (about 8.33 ms), and the second part is the remaining length of the frame period corresponding to the 91.4 Hz refresh rate (about 2.61 ms). It is easy to understand that the first part corresponds to the scanning area and the second part corresponds to the porch area.

[0153] In specific implementation, the display device can control the OLED to light up and turn off alternately according to 32 pulses in the scanning area. After completing 32 pulses in about 8.33ms, the OLED is controlled to light up and turn off alternately according to the separately set 10-pulse EM signal parameters within the remaining porch area length (about 2.61ms) of the frame period corresponding to the 91.4Hz refresh rate.

[0154] It should be noted that the end of the scanning area indicates that the driver IC has completed scanning the pixels of the current frame image through the GOA signal. Therefore, in the porch area corresponding to the 91.4Hz refresh rate, there is no need to perform repeated scanning operations on the pixels of the frame image, but the EM signal still needs to continue to control the OLED to light up and off alternately according to the set 10pulse.

[0155] According to the high-frequency PWM dimming solution provided in the embodiment of the present application, at a refresh rate of 90 Hz, firstly, a refresh rate of 120 Hz is used as the base frequency, 32 pulses are used as the reference pulse number corresponding to the base frequency, and a 3840 Hz PWM specification is used as the target. The reference pulse number corresponding to the base frequency is set in the scanning area as the EM signal parameter for controlling the alternating flickering of the OLED screen; and in the porch area, firstly, the result of dividing the target PWM frequency 3840 Hz by the refresh rate 90 Hz is obtained, and the result is 42.67 pulses, which is a non-integer; then, 42.67 pulses are rounded to obtain 43 pulses or 42 pulses; then, according to the difference between the rounded result and the reference pulse number, the integer pulse number corresponding to the porch area is obtained; finally, according to the target PWM frequency, the pulse number corresponding to the porch area and the reference pulse number, the actual refresh rate close to 90 Hz is reversely set, so as to achieve a dimming solution with a 3840 Hz PWM specification even at the 90 Hz gear. At the same time, it is also possible to apply the 3840Hz PWM specification dimming solution to the full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0156] It is worth noting that in addition to the above-mentioned schemes 1 and 2, the high-frequency PWM dimming method provided in the embodiment of the present application can also fine-tune the scanning time of each row of pixels for each reverse set refresh rate (89.3Hz or 91.4Hz) by the clock (CLK) of the driver IC in the Long-H scanning mode, uniformly compress the time, or uniformly stretch the time, so that the refresh rate can be accurately achieved again at 90Hz. It should be noted that each CLK signal will move and scan one pixel, so the scanning time of each row of pixels can be controlled by setting the CLK signal.

[0157] The following is an introduction to a method for more accurately achieving 90 Hz under the 3840 Hz PWM specification with reference to the accompanying drawings.

[0158] Solution 3: When the refresh rate is 89.3 Hz and the EM signal parameter is 43 pulses, the refresh rate is adjusted by compressing the scanning time of each scanning line in Long-H mode.

[0159] For example, Figure 7 As shown, after the refresh rate set in reverse for the Long-V mode is determined to be 89.3 Hz, the row scan duration is modified based on 89.3 Hz.

[0160] See also Figure 7 In some embodiments, when the refresh rate is reversely set to 89.3 Hz in Long-V mode, the driver IC can adjust the scanning time of each row of pixels in Long-H mode based on the 89.3 Hz refresh rate, so that the refresh rate reaches 90 Hz.

[0161] In some embodiments, in Long-H mode, the driver IC can adjust the scanning time of each row of pixels in each frame of the image through CLK. Therefore, if each frame of the image is scanned in Long-H mode, it can be compressed based on the scanning time of each row at a refresh rate of 89.3Hz, that is, the scanning time of each row of pixels is shortened, and the frame period of scanning each frame of the image is shortened, thereby increasing the refresh rate accordingly, and finally increasing the 89.3Hz refresh rate to an accurate 90Hz refresh rate.

[0162] Specifically, see Figure 7 The difference between the two oval frames is the difference between the duration of 3 frames of 89.3Hz refresh rate and the duration of 3 frames of 90Hz refresh rate. This difference (in duration) shows that the frame period of 89.3Hz refresh rate is longer than that of 90Hz, and the scanning time of each row of pixels is also longer than that of 90Hz. Therefore, by fine-tuning and compressing the scanning time of each row of pixels, the 89.3Hz refresh rate can be adjusted to the 90Hz refresh rate.

[0163] It should be noted that, under this solution, after the refresh rate is adjusted from 89.3Hz to 90Hz, the pixel scanning is performed through the Long-H mode, not the Long-V mode. It is just that in the process of obtaining 90Hz, the scanning parameters (such as frame period) of 89.3Hz obtained by the Long-V mode are used. In other words, the scheme three provided in the embodiment of the present application uses both the Long-V mode and the Long-H mode. Therefore, this scheme can be regarded as a hybrid scheme of the Long-V mode and the Long-H mode.

[0164] It should also be noted that the process of reversely setting (or deriving) the 89.3Hz refresh rate through the Long-V mode can be found in the introduction of the above-mentioned solution one, and will not be repeated here.

[0165] In some embodiments, when the refresh rate is adjusted to 90 Hz, the frequency of the high-frequency PWM is actually 3870 Hz, which can be obtained according to the following formula (1-10). For ease of understanding and setting, optionally, in actual applications, it can be regarded as or set to a 3840 Hz PWM specification close to it.

[0166] 90Hz×43pulse=3870Hz(1-10)

[0167] According to the high-frequency PWM dimming solution provided in the embodiment of the present application, at a refresh rate of 90 Hz, firstly, a refresh rate of 120 Hz is used as the base frequency, 32 pulses are used as the reference pulse number corresponding to the base frequency, and a 3840 Hz PWM specification is used as the target. The reference pulse number corresponding to the base frequency is set in the scanning area as the EM signal parameter for controlling the alternating flickering of the OLED screen; and in the porch area, firstly, the result of dividing the target PWM frequency 3840 Hz by the refresh rate 90 Hz is obtained, and the result is 42.67 pulses, which is a non-integer; then, 42.67 pulses are rounded to obtain 43 pulses or 42 pulses; then, according to the difference between the rounded result and the reference pulse number, the integer pulse number corresponding to the porch area is obtained; finally, according to the target PWM frequency, the pulse number corresponding to the porch area and the reference pulse number, the actual refresh rate close to 90 Hz is reversely set, so as to achieve a dimming solution with a 3840 Hz PWM specification even at the 90 Hz gear.

[0168] In addition, in Long-H mode, by adjusting the scanning time of each row of pixels at the actual refresh rate to obtain an accurate 90Hz refresh rate, it is possible to achieve a dimming solution with a 3840Hz PWM specification (actually a 3870Hz PWM specification) at precise 90Hz, and then realize the application of the dimming solution with a 3840Hz PWM specification to the full frame rate range of almost commonly used refresh rates, such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0169] Solution 4: When the refresh rate is 91.4 Hz and the EM signal parameter is 42 pulses, the refresh rate is adjusted by compressing the scanning time of each scanning line in Long-H mode.

[0170] For example, Figure 8As shown, after the refresh rate set in reverse for the Long-V mode is determined to be 91.4 Hz, the row scan duration is modified based on 91.4 Hz.

[0171] See also Figure 8 In some embodiments, when the refresh rate is reversely set to 91.4 Hz in Long-V mode, the driver IC can adjust the scanning time of each row of pixels in Long-H mode based on the 91.4 Hz refresh rate so that the refresh rate reaches 90 Hz.

[0172] In some embodiments, in Long-H mode, the driver IC can adjust the scanning time of each row of pixels in each frame of the image through CLK. Therefore, if each frame of the image is scanned in Long-H mode, the scanning time of each row can be stretched based on the 91.4Hz refresh rate, that is, the scanning time of each row of pixels is extended, and the frame period of scanning each frame of the image is also extended, so that the refresh rate is reduced accordingly, and the 91.4Hz refresh rate is reduced to a precise 90Hz refresh rate.

[0173] Specifically, see Figure 8 The difference between the two oval frames is the difference between the duration of 3 frames of 91.4Hz refresh rate and the duration of 3 frames of 90Hz refresh rate. This difference (in duration) shows that the frame period of 91.4Hz refresh rate is shorter than that of 90Hz, and the scanning duration of each row of pixels is also shorter than that of 90Hz. Therefore, by fine-tuning and stretching the scanning duration of each row of pixels, the 91.4Hz refresh rate can be adjusted to 90Hz refresh rate.

[0174] It should be noted that, under this solution, after the refresh rate is adjusted from 91.4Hz to 90Hz, the pixel scanning is performed through the Long-H mode, not the Long-V mode. It is just that in the process of obtaining 90Hz, the scanning parameters (such as frame period) of 91.4Hz obtained by the Long-V mode are used. In other words, the scheme 4 provided in the embodiment of the present application uses both the Long-V mode and the Long-H mode. Therefore, this scheme can be regarded as a hybrid scheme of the Long-V mode and the Long-H mode.

[0175] It should also be noted that the process of reversely setting (or deriving) the 91.4Hz refresh rate through the Long-V mode can be found in the introduction of the above-mentioned Solution 2, which will not be repeated here.

[0176] In some embodiments, when the refresh rate is adjusted to 90 Hz, the frequency of the high-frequency PWM is actually 3870 Hz, which can be obtained according to the formula (1-10) shown above. For ease of understanding and setting, optionally, in actual applications, it can be regarded as or set to a 3840 Hz PWM specification close to it.

[0177] According to the high-frequency PWM dimming solution provided in the embodiment of the present application, at a refresh rate of 90 Hz, firstly, a refresh rate of 120 Hz is used as the base frequency, 32 pulses are used as the reference pulse number corresponding to the base frequency, and a 3840 Hz PWM specification is used as the target. The reference pulse number corresponding to the base frequency is set in the scanning area as the EM signal parameter for controlling the alternating flickering of the OLED screen; and in the porch area, firstly, the result of dividing the target PWM frequency 3840 Hz by the refresh rate 90 Hz is obtained, and the result is 42.67 pulses, which is a non-integer; then, 42.67 pulses are rounded to obtain 43 pulses or 42 pulses; then, according to the difference between the rounded result and the reference pulse number, the integer pulse number corresponding to the porch area is obtained; finally, according to the target PWM frequency, the pulse number corresponding to the porch area and the reference pulse number, the actual refresh rate close to 90 Hz is reversely set, so as to achieve a dimming solution with a 3840 Hz PWM specification even at the 90 Hz gear.

[0178] In addition, in Long-H mode, by adjusting the scanning time of each row of pixels at the actual refresh rate to obtain an accurate 90Hz refresh rate, it is possible to achieve a dimming solution with a 3840Hz PWM specification (actually a 3870Hz PWM specification) at precise 90Hz, and then realize the application of the dimming solution with a 3840Hz PWM specification to the full frame rate range of almost commonly used refresh rates, such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0179] For example, Fig. 9 FIG. 1 is a schematic flow chart of a high-frequency PWM dimming method provided in an embodiment of the present application. The process can be executed by a display device as a main body, and specifically can include the following steps:

[0180] S901, setting the target refresh rate as the base frequency, and setting the EM signal parameter corresponding to the base frequency as the reference pulse number.

[0181] The refresh rate here refers to the Long-V mode. The target refresh rate as the base frequency can be 120Hz as described above, and the reference pulse number corresponding to the base frequency can be 32pulse as described above. In the embodiment of the present application, the reference pulse number can also be described as a reference EM signal parameter, which refers to the number of EM signal pulses that the driver IC of the display device controls the screen of the display device to light up or turn off within a unit time (1s). The screen of the display device here may include the OLED screen described above.

[0182] In some embodiments, the EM signal parameters at a refresh rate of 120 Hz are set to 32 pulses, and when PWM dimming is used, the frequency can reach 3840 Hz.

[0183] It should be noted that the embodiments of the present application are mainly described with the currently commonly used 120Hz as the base frequency and the PWM dimming frequency of 3840Hz as the target, but in actual applications, the design concept of the present application is not limited to this. For example, the base frequency can also be a higher frequency that can be achieved now or in the future, and the PWM dimming frequency target can also be a higher frequency, which is not limited in the embodiments of the present application.

[0184] S902, in a scanning area of ​​a first refresh rate frame period, setting the corresponding pulse number as a reference pulse number, wherein the duration of the scanning area is the same as the duration of the base frequency frame period.

[0185] In some embodiments, the first refresh rate may refer to a commonly used refresh rate other than the base frequency, which is less than the base frequency, and may or may not be divisible by the base frequency. For example, these refresh rates may include: 90 Hz, 60 Hz, 40 Hz, 30 Hz, 20 Hz, 10 Hz, etc.

[0186] It should be noted that, in the embodiment of the present application, the frame period of the first refresh rate can be divided into a scanning area and a porch area.

[0187] The scanning area refers to the area corresponding to the period of time when the scanning operation is performed on the image pixels. The scanning area is aligned with the frame period of the base frequency and has the same duration. For example, if the base frequency is 120Hz, then the duration of the base frequency frame period is about 8.33ms. If the scanning period corresponding to a frame image is from 00:00 to (00:00+8.33ms) at a refresh rate of 120Hz, then the period of the scanning area corresponding to the first refresh rate can also be set to be from 00:00 to (00:00+8.33ms), and its duration is also 8.33ms.

[0188] The porch area refers to the area after the scanning operation is performed on the image pixels. There is no need to scan the pixels repeatedly in the porch area. The duration of the porch area is the remaining duration after subtracting the scanning area duration from the frame period of the first refresh rate. For a more detailed introduction to the scanning area and porch area, please refer to Figures 2 to 8 Related content in .

[0189] In some embodiments, the display device can scan the pixels of the current frame image in the scanning area corresponding to the first refresh rate according to the Long-V mode, that is, scan the pixels line by line from left to right and from top to bottom. When the scanning area ends, all the pixels of the current frame image are scanned. Among them, the driver IC in the display device can control the scanning of the pixels through the GOA signal.

[0190] In addition, in the scanning area corresponding to the first refresh rate, the display device can also control the display device screen to light up or turn off according to the reference pulse number through the EM signal, so that the screen is in an alternating state of light and light, allowing the user to visually perceive the brightness change of the screen. For example, the reference pulse number of the base frequency 120Hz is 32, then in the scanning area of ​​the first refresh rate, the driver IC in the display device will control the screen to light up and turn off alternately according to the 32-pulse EM signal.

[0191] S903A, in the porch area corresponding to the second refresh rate, obtain the pulse number set for the porch area according to the target PWM frequency, the PWM frequency corresponding to the scanning area and the second refresh rate, wherein the second refresh rate is the refresh rate of the first refresh rate that cannot divide the base frequency.

[0192] In some embodiments, before executing step S903A, it can also be determined whether the current refresh rate can be divided evenly by the base frequency. If not, the process from S903A to S905A is executed; if it can be divided evenly, the process in steps S903B and S904B is jumped to execute.

[0193] The number of pulses set for the porch area can be calculated by the following process: (1) According to the formula (1-1) shown above, the number of pulses required to achieve the 3840Hz PWM specification at a refresh rate of 90Hz is calculated, that is, 42.67pulses; (2) According to 42.67pulses, the two nearest integers are taken, and the rounded result is 43pulses or 42pulses; (3) According to the formula (1-2) or formula (1-3) shown above, the difference between the rounded result 43pulses or 42pulses and the reference pulse number is calculated, and the difference result is 11pulses or 10pulses, that is, the number of pulses set for the porch area at a refresh rate of 90Hz.

[0194] S904A, reversely obtain the actual refresh rate according to the reference pulse number, the pulse number set for the porch area, and the target PWM frequency.

[0195] In some embodiments, the actual refresh rate can be obtained by reverse calculation using the following process formula (1-11).

[0196] Actual refresh rate = target PWM frequency ÷ (reference pulse number + pulse number set for porch area)

[0197] (1-11)

[0198] Specifically, when the second refresh rate is 90 Hz and the number of pulses set for the porch area is 11 pulses, the actual refresh rate can be calculated to be 89.3 Hz according to the above formula (1-11). When the second refresh rate is 90 Hz and the number of pulses set for the porch area is 10 pulses, the actual refresh rate can be calculated to be 91.4 Hz according to the above formula (1-11).

[0199] It is understandable that the actual refresh rate is a frequency very close to the second refresh rate, so in practical applications, it can be regarded as or set as the second refresh rate level. For example, 89.3 Hz and / or 91.4 Hz can be regarded as or set as the 90 Hz level.

[0200] S905A, at the second refresh rate gear, refresh the screen according to the actual refresh rate; and light up or turn off the screen of the display device according to the reference pulse number corresponding to the scanning area and the pulse number corresponding to the porch area of ​​the second refresh rate.

[0201] In some embodiments, the driver IC in the display device can refresh the screen according to the actual refresh rate; and the driver IC in the display device can control the screen to alternately light up and off through the EM signal according to the reference pulse number in the scanning area and the pulse number set for the porch area in the porch area.

[0202] S903B, in the porch area corresponding to the third refresh rate, copy the reference pulse number once or multiple times so that the EM signal covers the porch area, wherein the third refresh rate is a refresh rate of the first refresh rate that can divide the base frequency.

[0203] In some embodiments, before executing step S903B, it can also be determined whether the current refresh rate can be divided evenly by the base frequency. If it can be divided evenly, the process from S903B to S904B is executed; if it cannot be divided evenly, the process from step S903A to step S905A is jumped to execute.

[0204] It should be noted that since the duration of the scanning area of ​​the third refresh rate is the same as the frame period of the base frequency, and the duration of the pole area is the remaining duration after deducting the duration of the scanning area from the frame period of the third refresh rate, when the third refresh rate is different, the duration of the pole area is also different, resulting in different number of times the pole area copies the benchmark pulse number.

[0205] Specifically, when the base frequency is 120Hz, the refresh rate that can divide the base frequency can include 40Hz, 30Hz, 20Hz, 10Hz, etc. in addition to the 60Hz mainly introduced above. For example, when the third refresh rate is 60Hz, the duration of the scanning area is about 8.33ms, and the duration of the porch area is also about 8.33ms. At this time, the reference pulse number can be copied once in its corresponding porch area. That is, at a refresh rate of 60Hz, the EM signal parameter corresponding to the scanning area is 1 reference pulse number, and the EM signal parameter corresponding to the porch area is also 1 reference pulse number. For another example, when the third refresh rate is 40Hz, the duration of the scanning area is about 8.33ms, and the duration of the porch area is about 1.66ms (that is, 2 8.33ms). At this time, the reference pulse number can be copied twice in its corresponding porch area, that is, the EM signal parameter corresponding to the scanning area is 1 reference pulse number, and the EM signal parameter corresponding to the porch area is 2 reference pulse numbers. For other refresh rates that can divide the base frequency, the EM signal parameters corresponding to the scanning area and the porch area can be set in a similar manner to 60 Hz and 40 Hz, and will not be described in detail here.

[0206] S904B, in the third refresh rate gear, refreshing the screen according to the third refresh rate; and lighting or extinguishing the screen of the display device according to the copied reference pulse number corresponding to the third refresh rate.

[0207] According to the high-frequency PWM dimming solution provided in the embodiment of the present application, at a refresh rate of 90 Hz, firstly, a refresh rate of 120 Hz is used as the base frequency, 32 pulses are used as the reference pulse number corresponding to the base frequency, and a 3840 Hz PWM specification is used as the target. The reference pulse number corresponding to the base frequency is set in the scanning area as the EM signal parameter for controlling the alternating flickering of the OLED screen; and in the porch area, firstly, the result of dividing the target PWM frequency 3840 Hz by the refresh rate 90 Hz is obtained, and the result is approximately 42.67 pulses, which is a non-integer; then, 42.67 pulses are rounded to obtain 43 pulses or 42 pulses; then, according to the difference between the rounded result and the reference pulse number, the pulse number (integer) corresponding to the porch area is obtained; finally, according to the target PWM frequency, the pulse number corresponding to the porch area and the reference pulse number, the actual refresh rate close to 90 Hz is reversely set, so as to achieve a dimming solution with a 3840 Hz PWM specification even at the 90 Hz gear. At the same time, it is also possible to apply the 3840Hz PWM specification dimming solution to the full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0208] For example, Fig.10 FIG. 1 is a schematic flow chart of another high-frequency PWM dimming method provided in an embodiment of the present application. The execution subject of the process may be a display device, and specifically includes the following steps:

[0209] S1001, setting the target refresh rate as the base frequency, and setting the number of EM signal pulses for brightness control corresponding to the base frequency as the reference pulse number.

[0210] S1002, in a scanning area of ​​a first refresh rate frame period, setting the number of EM signal pulses corresponding to the scanning area as a reference number of pulses, wherein the duration of the scanning area is the same as the duration of the base frequency frame period.

[0211] S1003, in the first porch area corresponding to the second refresh rate, the number of first EM signal pulses corresponding to the first porch area is set according to the target pulse width modulation PWM frequency, the PWM frequency corresponding to the scanning area and the second refresh rate, wherein the second refresh rate is the refresh rate of the first refresh rate that cannot be divided by the base frequency, and the number of first EM signal pulses is an integer.

[0212] In some embodiments, in the first porch area corresponding to the second refresh rate, the number of first EM signal pulses corresponding to the first porch area is set according to the target PWM frequency, the PWM frequency corresponding to the scanning area and the second refresh rate, specifically including the following process: obtaining a first result after the target PWM frequency is divided by the second refresh rate, the first result is a non-integer; according to the first result, obtaining a first integer closest to the first result; and setting the number of first EM signal pulses corresponding to the first porch area according to the first integer.

[0213] Among them, the target PWM frequency is 3840Hz, the second refresh rate is 90Hz, the base frequency is 120Hz, the reference pulse number is 32pulse, the first integer is 11pulse, and the actual refresh rate is 91.4Hz.

[0214] Optionally, in the first porch area corresponding to the second refresh rate, the number of first EM signal pulses corresponding to the first porch area is set according to the target PWM frequency, the PWM frequency corresponding to the scanning area and the second refresh rate, and the following process may also be included: obtaining a first difference between the target PWM frequency and the PWM frequency corresponding to the scanning area; calculating a first result after dividing the first difference by the second refresh rate, the first result being a non-integer; obtaining a first integer closest to the first result according to the first result; and setting the number of first EM signal pulses corresponding to the first porch area according to the first integer.

[0215] In some embodiments, in the first porch area corresponding to the second refresh rate, the number of first EM signal pulses corresponding to the first porch area is set according to the target PWM frequency, the PWM frequency corresponding to the scanning area and the second refresh rate, and the following process may be specifically included: obtaining a first result after the target PWM frequency is divided by the second refresh rate, the first result is a non-integer; according to the first result, obtaining a second integer that is the second closest to the first result; and setting the number of first EM signal pulses corresponding to the first porch area according to the second integer.

[0216] Among them, the target PWM frequency is 3840Hz, the second refresh rate is 90Hz, the base frequency is 120Hz, the reference pulse number is 32pulse, the second integer is 10pulse, and the actual refresh rate is 91.4Hz.

[0217] Optionally, in the first porch area corresponding to the second refresh rate, the number of first EM signal pulses corresponding to the first porch area is set according to the target PWM frequency, the PWM frequency corresponding to the scanning area and the second refresh rate, and the following process may also be included: obtaining a first difference between the target PWM frequency and the PWM frequency corresponding to the scanning area; calculating a first result after dividing the first difference by the second refresh rate, the first result being a non-integer; obtaining a second integer that is the second closest to the first result according to the first result; and setting the number of first EM signal pulses corresponding to the first porch area according to the second integer.

[0218] S1004, according to the target PWM frequency, the reference pulse number and the first EM signal pulse number, reversely obtain the actual refresh rate corresponding to the second refresh rate level.

[0219] In some embodiments, based on the target PWM frequency, the reference pulse number and the first EM signal pulse number, reversely obtaining the actual refresh rate corresponding to the second refresh rate gear can specifically include: summing the reference pulse number and the first EM signal pulse number to obtain a second result; obtaining a third result after dividing the target PWM frequency by the second result, and the third result is the actual refresh rate corresponding to the second refresh rate gear.

[0220] S1005, at the second refresh rate gear, refresh the screen of the display device according to the actual refresh rate; and light up or turn off the screen of the display device according to the number of reference pulses corresponding to the scanning area of ​​the second refresh rate and the number of first EM signal pulses corresponding to the first porch area.

[0221] In some embodiments, the actual refresh rate corresponding to the second refresh rate gear is obtained in Long-V mode, and the method also includes: in Long-H mode, according to the actual refresh rate, adjusting the duration of scanning each row of pixels in the image during refresh, and obtaining the adjusted first row scanning duration, wherein the first row scanning duration causes the refresh rate corresponding to the refresh to be adjusted to the second refresh rate.

[0222] In some embodiments, the method further includes: replicating the reference pulse number once or multiple times for the EM signal in a second porch area corresponding to a third refresh rate, wherein the third refresh rate is a refresh rate in the first refresh rate that is divisible by the base frequency; at the third refresh rate, refreshing the screen of the display device according to the third refresh rate; and lighting up or turning off the screen of the display device according to the reference pulse number corresponding to the scanning area of ​​the third refresh rate and the replicated reference pulse number corresponding to the second porch area.

[0223] In some embodiments, the method further includes: the operation of refreshing the screen of the display device is performed only in the scanning area.

[0224] According to the high-frequency PWM dimming solution provided in the embodiment of the present application, at a refresh rate of 90 Hz, firstly, a refresh rate of 120 Hz is used as the base frequency, 32 pulses are used as the reference pulse number corresponding to the base frequency, and a 3840 Hz PWM specification is used as the target. The reference pulse number corresponding to the base frequency is set in the scanning area as the EM signal parameter for controlling the alternating flickering of the OLED screen; and in the porch area, firstly, the result of dividing the target PWM frequency 3840 Hz by the refresh rate 90 Hz is obtained, and the result is 42.67 pulses, which is a non-integer; then, 42.67 pulses are rounded to obtain 43 pulses or 42 pulses; then, according to the difference between the rounded result and the reference pulse number, the integer pulse number corresponding to the porch area is obtained; finally, according to the target PWM frequency, the pulse number corresponding to the porch area and the reference pulse number, the actual refresh rate close to 90 Hz is reversely set, so as to achieve a dimming solution with a 3840 Hz PWM specification even at the 90 Hz gear.

[0225] In addition, in Long-H mode, by adjusting the scanning time of each row of pixels at the actual refresh rate to obtain an accurate 90Hz refresh rate, it is possible to achieve a dimming solution with a 3840Hz PWM specification (actually a 3870Hz PWM specification) at precise 90Hz, and then realize the application of the dimming solution with a 3840Hz PWM specification to the full frame rate range of almost commonly used refresh rates, such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0226] The high-frequency PWM dimming method provided in the embodiment of the present application can be applied to various types of display devices with OLED screens, such as mobile phones, tablet computers, wearable devices, laptop computers, desktop computers, netbooks, personal digital assistants (PDAs), etc. The embodiment of the present application does not impose any restrictions on the type of display device.

[0227] For example, Fig.11 , which is a schematic structural diagram of a display device 100 provided in an embodiment of the present application.

[0228] The display device 100 may include a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charging management module 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, an earphone interface 170D, a sensor module 180, a button 190, a motor 191, an indicator 192, a camera 193, a display screen 194, and a subscriber identification module (SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, an air pressure sensor 180C, a magnetic sensor 180D, an acceleration sensor 180E, a distance sensor 180F, a proximity light sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, etc.

[0229] It is understood that the structure illustrated in the embodiment of the present invention does not constitute a specific limitation on the display device 100. In other embodiments of the present application, the display device 100 may include more or fewer components than shown in the figure, or combine some components, or separate some components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0230] The processor 110 may include one or more processing units, for example, the processor 110 may include an application processor (AP), a modem processor, a graphics processor (GPU), an image signal processor (ISP), a controller, a memory, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU), etc. Different processing units may be independent devices or integrated into one or more processors.

[0231] The controller may be the nerve center and command center of the display device 100. The controller may generate an operation control signal according to the instruction operation code and the timing signal to complete the control of fetching and executing instructions.

[0232] The processor 110 may also be provided with a memory for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. The memory may store instructions or data that the processor 110 has just used or cyclically used. If the processor 110 needs to use the instruction or data again, it may be directly called from the memory. This avoids repeated access, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0233] In some embodiments, the processor 110 may include one or more interfaces. The interface may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc.

[0234] The I2C interface is a bidirectional synchronous serial bus, including a serial data line (SDA) and a serial clock line (SCL). In some embodiments, the processor 110 may include multiple groups of I2C buses. The processor 110 may be coupled to the touch sensor 180K, the charger, the flash, the camera 193, etc. through different I2C bus interfaces. For example, the processor 110 may be coupled to the touch sensor 180K through the I2C interface, so that the processor 110 communicates with the touch sensor 180K through the I2C bus interface to realize the touch function of the display device 100.

[0235] The I2S interface can be used for audio communication. In some embodiments, the processor 110 can include multiple I2S buses. The processor 110 can be coupled to the audio module 170 via the I2S bus to achieve communication between the processor 110 and the audio module 170. In some embodiments, the audio module 170 can transmit an audio signal to the wireless communication module 160 via the I2S interface to achieve the function of answering a call through a Bluetooth headset.

[0236] The PCM interface can also be used for audio communication, sampling, quantizing and encoding analog signals. In some embodiments, the audio module 170 and the wireless communication module 160 can be coupled via a PCM bus interface. In some embodiments, the audio module 170 can also transmit audio signals to the wireless communication module 160 via the PCM interface to realize the function of answering calls via a Bluetooth headset. Both the I2S interface and the PCM interface can be used for audio communication.

[0237] The UART interface is a universal serial data bus for asynchronous communication. The bus can be a bidirectional communication bus. It converts the data to be transmitted between serial communication and parallel communication. In some embodiments, the UART interface is generally used to connect the processor 110 and the wireless communication module 160. For example, the processor 110 communicates with the Bluetooth module in the wireless communication module 160 through the UART interface to implement the Bluetooth function. In some embodiments, the audio module 170 can transmit an audio signal to the wireless communication module 160 through the UART interface to implement the function of playing music through a Bluetooth headset.

[0238] The MIPI interface can be used to connect the processor 110 with peripheral devices such as the display screen 194 and the camera 193. The MIPI interface includes a camera serial interface (CSI), a display serial interface (DSI), etc. In some embodiments, the processor 110 and the camera 193 communicate via the CSI interface to implement the shooting function of the display device 100. The processor 110 and the display screen 194 communicate via the DSI interface to implement the display function of the display device 100.

[0239] The GPIO interface can be configured by software. The GPIO interface can be configured as a control signal or as a data signal. In some embodiments, the GPIO interface can be used to connect the processor 110 with the camera 193, the display 194, the wireless communication module 160, the audio module 170, the sensor module 180, etc. The GPIO interface can also be configured as an I2C interface, an I2S interface, a UART interface, a MIPI interface, etc.

[0240] The USB interface 130 is an interface that complies with the USB standard specification, and specifically can be a Mini USB interface, a Micro USB interface, a USB Type C interface, etc. The USB interface 130 can be used to connect a charger to charge the display device 100, and can also be used to transmit data between the display device 100 and peripheral devices. It can also be used to connect headphones to play audio through the headphones. The interface can also be used to connect other terminals, such as AR devices, etc.

[0241] It is understandable that the interface connection relationship between the modules illustrated in the embodiment of the present invention is only a schematic illustration and does not constitute a structural limitation on the display device 100. In other embodiments of the present application, the display device 100 may also adopt different interface connection methods in the above embodiments, or a combination of multiple interface connection methods.

[0242] The charging management module 140 is used to receive charging input from a charger. The charger may be a wireless charger or a wired charger. In some wired charging embodiments, the charging management module 140 may receive charging input from a wired charger through the USB interface 130. In some wireless charging embodiments, the charging management module 140 may receive wireless charging input through a wireless charging coil of the display device 100. While the charging management module 140 is charging the battery 142, it may also power the terminal through the power management module 141.

[0243] The power management module 141 is used to connect the battery 142, the charging management module 140 and the processor 110. The power management module 141 receives input from the battery 142 and / or the charging management module 140, and supplies power to the processor 110, the internal memory 121, the external memory, the display screen 194, the camera 193, and the wireless communication module 160. The power management module 141 can also be used to monitor parameters such as battery capacity, battery cycle number, battery health status (leakage, impedance), etc. In some other embodiments, the power management module 141 can also be set in the processor 110. In other embodiments, the power management module 141 and the charging management module 140 can also be set in the same device.

[0244] The wireless communication function of the display device 100 can be implemented through the antenna 1, the antenna 2, the mobile communication module 150, the wireless communication module 160, the modem processor and the baseband processor.

[0245] Antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in display device 100 can be used to cover a single or multiple communication frequency bands. Different antennas can also be reused to improve the utilization of the antennas. For example, antenna 1 can be reused as a diversity antenna for a wireless local area network. In some other embodiments, the antenna can be used in combination with a tuning switch.

[0246] The mobile communication module 150 can provide solutions for wireless communications including 2G / 3G / 4G / 5G applied to the display device 100. The mobile communication module 150 may include at least one filter, a switch, a power amplifier, a low noise amplifier (LNA), etc. The mobile communication module 150 can receive electromagnetic waves from the antenna 1, and filter, amplify, and process the received electromagnetic waves, and transmit them to the modulation and demodulation processor for demodulation. The mobile communication module 150 can also amplify the signal modulated by the modulation and demodulation processor, and convert it into electromagnetic waves for radiation through the antenna 1. In some embodiments, at least some of the functional modules of the mobile communication module 150 can be set in the processor 110. In some embodiments, at least some of the functional modules of the mobile communication module 150 can be set in the same device as at least some of the modules of the processor 110.

[0247] The modem processor may include a modulator and a demodulator. Among them, the modulator is used to modulate the low-frequency baseband signal to be sent into a medium-high frequency signal. The demodulator is used to demodulate the received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transmits the demodulated low-frequency baseband signal to the baseband processor for processing. After the low-frequency baseband signal is processed by the baseband processor, it is passed to the application processor. The application processor outputs a sound signal through an audio device (not limited to a speaker 170A, a receiver 170B, etc.), or displays an image or video through a display screen 194. In some embodiments, the modem processor may be an independent device. In other embodiments, the modem processor may be independent of the processor 110 and be set in the same device as the mobile communication module 150 or other functional modules.

[0248] The wireless communication module 160 can provide wireless communication solutions including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared (IR), etc., which are applied to the display device 100. The wireless communication module 160 can be one or more devices integrating at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via the antenna 2, modulates the frequency of the electromagnetic wave signal and filters it, and sends the processed signal to the processor 110. The wireless communication module 160 can also receive the signal to be sent from the processor 110, modulate the frequency of it, amplify it, and convert it into electromagnetic waves for radiation through the antenna 2.

[0249] In some embodiments, the antenna 1 of the display device 100 is coupled to the mobile communication module 150, and the antenna 2 is coupled to the wireless communication module 160, so that the display device 100 can communicate with the network and other devices through wireless communication technology. The wireless communication technology may include global system for mobile communications (GSM), general packet radio service (GPRS), code division multiple access (CDMA), wideband code division multiple access (WCDMA), time-division code division multiple access (TD-SCDMA), long term evolution (LTE), BT, GNSS, WLAN, NFC, FM, and / or IR technology, etc. The GNSS may include a global positioning system (GPS), a global navigation satellite system (GLONASS), a Beidou navigation satellite system (BDS), a quasi-zenith satellite system (QZSS) and / or a satellite based augmentation system (SBAS).

[0250] The display device 100 implements display functions through a GPU, a display screen 194, and an application processor, etc. The display screen 194 is used to display images, videos, and the like.

[0251] The display device 100 can realize the shooting function through an ISP, a camera 193, a video codec, a GPU, a display screen 194, and an application processor.

[0252] The digital signal processor is used to process digital signals. In addition to processing digital image signals, it can also process other digital signals. For example, when the display device 100 is selecting a frequency point, the digital signal processor is used to perform Fourier transform on the frequency point energy. The video codec is used to compress or decompress digital video. The NPU is a neural network (NN) computing processor that quickly processes input information by drawing on the structure of biological neural networks, such as the transmission mode between neurons in the human brain, and can also continuously self-learn.

[0253] The external memory interface 120 can be used to connect an external memory card, such as a Micro SD card, to expand the storage capacity of the display device 100. The external memory card communicates with the processor 110 through the external memory interface 120 to implement a data storage function. For example, files such as music and videos are saved in the external memory card. The internal memory 121 can be used to store computer executable program codes, which include instructions.

[0254] The display device 100 can implement audio functions such as music playing and recording through the audio module 170 , the speaker 170A, the receiver 170B, the microphone 170C, the headphone jack 170D, and the application processor.

[0255] The pressure sensor 180A is used to sense the pressure signal and can convert the pressure signal into an electrical signal. The gyroscope sensor 180B can be used to determine the motion posture of the display device 100. The magnetic sensor 180D includes a Hall sensor. The display device 100 can use the magnetic sensor 180D to detect the opening and closing of the flip leather case. The acceleration sensor 180E can detect the magnitude of the acceleration of the display device 100 in various directions (generally three axes). When the display device 100 is stationary, the magnitude and direction of gravity can be detected. It can also be used to identify the terminal posture and applied to horizontal and vertical screen switching, pedometers and other applications. The proximity light sensor 180G may include, for example, a light emitting diode (LED) and a light detector, such as a photodiode. The light emitting diode may be an infrared light emitting diode. The display device 100 emits infrared light outward through the light emitting diode. The ambient light sensor 180L is used to sense the brightness of the ambient light. The display device 100 can adaptively adjust the brightness of the display screen 194 according to the perceived ambient light brightness. The fingerprint sensor 180H is used to collect fingerprints. The temperature sensor 180J is used to detect the temperature. The touch sensor 180K is also called a "touch panel". The touch sensor 180K can be set on the display screen 194, and the touch sensor 180K and the display screen 194 form a touch screen, also called a "touch screen". The touch sensor 180K is used to detect touch operations acting on or near it. The bone conduction sensor 180M can obtain vibration signals.

[0256] In addition, the display device 100 further includes an air pressure sensor 180C and a distance sensor 180F. The air pressure sensor 180C is used to measure air pressure. In some embodiments, the display device 100 calculates the altitude through the air pressure value measured by the air pressure sensor 180C to assist positioning and navigation.

[0257] The distance sensor 180F is used to measure the distance. The display device 100 can measure the distance by infrared or laser. In some embodiments, when shooting a scene, the display device 100 can use the distance sensor 180F to measure the distance to achieve fast focusing.

[0258] Exemplarily, the software system of the display device 100 may adopt a layered architecture, an event-driven architecture, a micro-core architecture, a micro-service architecture, or a cloud architecture. The present application embodiment takes the Android system of the layered architecture as an example to exemplify the software structure of the display device 100. Fig.12 It is a software structure block diagram of the display device 100 according to an embodiment of the present application.

[0259] The layered architecture divides the software into several layers, each with clear roles and division of labor. The layers communicate with each other through software interfaces. In some embodiments, the Android system is divided into four layers, from top to bottom: application layer, application framework layer, Android runtime, system library, kernel layer, hardware abstraction layer (HAL), and hardware layer.

[0260] The application layer can include a series of application packages. Fig.12 As shown, the application package may include applications such as camera, calendar, map, WLAN, music, short message, gallery, call, navigation, Bluetooth, video, etc.

[0261] The application framework layer provides application programming interface (API) and programming framework for the applications in the application layer. The application framework layer includes some predefined functions. Fig.12 As shown, the application framework layer may include a window manager, a content provider, a phone manager, a resource manager, a notification manager, a view system, and the like.

[0262] The window manager is used to manage window programs. The window manager can obtain the display screen size, determine whether there is a status bar, lock the screen, capture the screen, etc.

[0263] Content providers are used to store and retrieve data and make it accessible to applications. The data may include videos, images, audio, calls made and received, browsing history and bookmarks, phone books, etc.

[0264] The view system includes visual controls, such as controls for displaying text, controls for displaying images, etc. The view system can be used to build applications. A display interface can be composed of one or more views. For example, a display interface including a text notification icon can include a view for displaying text and a view for displaying images.

[0265] The phone manager is used to provide communication functions of the display device 100, such as management of call status (including connected, hung up, etc.).

[0266] The resource manager provides various resources for applications, such as localized strings, icons, images, layout files, video files, and so on.

[0267] The notification manager enables applications to display notification information in the status bar. It can be used to convey notification-type messages and can disappear automatically after a short stay without user interaction. For example, the notification manager is used to notify download completion, message reminders, etc. The notification manager can also be a notification that appears in the system top status bar in the form of a chart or scroll bar text, such as notifications of applications running in the background, or a notification that appears on the screen in the form of a dialog window. For example, a text message is displayed in the status bar, a prompt sound is emitted, the terminal vibrates, the indicator light flashes, etc.

[0268] Android Runtime includes core libraries and virtual machines. Android Runtime is responsible for scheduling and management of the Android system.

[0269] The core library consists of two parts: one part is the function that needs to be called by the Java language, and the other part is the Android core library.

[0270] The application layer and the application framework layer run in the virtual machine. The virtual machine executes the java files of the application layer and the application framework layer as binary files. The virtual machine is used to perform functions such as obstacle life cycle management, stack management, thread management, security and exception management, and garbage collection.

[0271] The system library may include multiple functional modules, such as surface manager, media library, 3D graphics processing library (such as OpenGL ES), 2D graphics engine (such as SGL), etc.

[0272] The surface manager is used to manage the display subsystem and provide the fusion of 2D and 3D layers for multiple applications.

[0273] The media library supports playback and recording of a variety of commonly used audio and video formats, as well as static image files, etc. The media library can support a variety of audio and video encoding formats, such as: MPEG4, H.264, MP3, AAC, AMR, JPG, PNG, etc.

[0274] The 3D graphics processing library is used to implement 3D graphics drawing, image rendering, compositing, and layer processing.

[0275] A 2D graphics engine is a drawing engine for 2D drawings.

[0276] The kernel layer is the layer between hardware and software. The kernel layer contains at least display driver, camera sensor driver, audio driver, and sensor driver.

[0277] Based on the same technical concept, an embodiment of the present application also provides a display device, including one or more processors; one or more memories; the one or more memories store one or more computer programs, and the one or more computer programs include instructions. When the instructions are executed by the one or more processors, the computer or processor executes one or more steps in any of the above methods.

[0278] Based on the same technical concept, an embodiment of the present application also provides a computer-readable storage medium, which stores computer-executable program instructions. When the computer-executable program instructions are executed on a computer, the computer or processor executes one or more steps in any of the above methods.

[0279] Based on the same technical concept, an embodiment of the present application also provides a computer program product comprising instructions, wherein the computer program product includes computer program code. When the computer program code runs on a computer, the computer or processor executes one or more steps in any of the above methods.

[0280] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions may be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state drive (SSD)), etc.

[0281] Those skilled in the art can understand that to implement all or part of the processes in the above-mentioned embodiments, the processes can be completed by computer programs to instruct related hardware, and the programs can be stored in computer-readable storage media. When the programs are executed, they can include the processes of the above-mentioned method embodiments. The aforementioned storage media include: ROM or random access memory RAM, magnetic disk or optical disk and other media that can store program codes.

[0282] The above is only a specific implementation of the embodiment of the present application, but the protection scope of the embodiment of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed in the embodiment of the present application should be included in the protection scope of the embodiment of the present application. Therefore, the protection scope of the embodiment of the present application should be based on the protection scope of the claims.

Claims

1. A high frequency PWM dimming method, characterized in that: Applied to display devices, including: The display device displays at a first refresh rate; In the scanning area of ​​the first refresh rate frame period, the number of pulses of the brightness control EM signal is the reference pulse number, the reference pulse number is the number of pulses of the EM signal corresponding to the target refresh rate, the target refresh rate can be divided by the target pulse width modulation PWM frequency, and the frequency of the target refresh rate is the base frequency, and the duration of the scanning area of ​​the first refresh rate frame period is the same as the duration of the base frequency frame period; If the first refresh rate cannot divide the base frequency, obtaining the number of first EM signal pulses corresponding to the porch area of ​​the first refresh rate according to the target PWM frequency, the PWM frequency corresponding to the scanning area of ​​the first refresh rate, and the first refresh rate, wherein the number of first EM signal pulses is an integer; Acquire an actual refresh rate corresponding to the first refresh rate according to the target PWM frequency, the reference pulse number and the first EM signal pulse number; Refresh the screen of the display device according to the actual refresh rate; and The screen of the display device is turned on or off according to the reference pulse number corresponding to the scanning area of ​​the first refresh rate and the first EM signal pulse number corresponding to the porch area.

2. The method according to claim 1, characterized in that If the first refresh rate cannot divide the base frequency, obtaining the number of first EM signal pulses corresponding to the porch area of ​​the first refresh rate according to the target PWM frequency, the PWM frequency corresponding to the scanning area of ​​the first refresh rate, and the first refresh rate, specifically includes: Obtaining a first result after dividing the target PWM frequency by the first refresh rate, where the first result is a non-integer; According to the first result, obtaining a first integer closest to the first result; The first EM signal pulse number corresponding to the porch area is set according to the first integer.

3. The method according to claim 2, characterized in that The target PWM frequency is 3840 Hz, the first refresh rate is 90 Hz, the base frequency is 120 Hz, the reference pulse number is 32 pulses, the first integer is 11 pulses, and the actual refresh rate is 89.3 Hz.

4. The method according to claim 1, characterized in that: If the first refresh rate cannot divide the base frequency, obtaining the number of first EM signal pulses corresponding to the porch area of ​​the first refresh rate according to the target PWM frequency, the PWM frequency corresponding to the scanning area of ​​the first refresh rate, and the first refresh rate, specifically includes: Obtaining a first result after dividing the target PWM frequency by the first refresh rate, where the first result is a non-integer; According to the first result, obtaining a second integer that is second closest to the first result; The number of first EM signal pulses corresponding to the porch area is set according to the second integer.

5. The method according to claim 4, characterized in that The target PWM frequency is 3840 Hz, the first refresh rate is 90 Hz, the base frequency is 120 Hz, the reference pulse number is 32 pulses, the second integer is 10 pulses, and the actual refresh rate is 91.4 Hz.

6. The method according to any one of claims 1 to 5, characterized in that The acquiring, according to the target PWM frequency, the reference pulse number and the first EM signal pulse number, an actual refresh rate corresponding to the first refresh rate specifically includes: Calculating the sum of the reference pulse number and the first EM signal pulse number to obtain a second result; A third result obtained by dividing the target PWM frequency by the second result is obtained, where the third result is an actual refresh rate corresponding to the first refresh rate.

7. The method according to any one of claims 1 to 5, characterized in that The actual refresh rate corresponding to the first refresh rate gear is obtained in the Long-V mode, and the method further includes: In Long-H mode, the duration of scanning each row of pixels in the image during refresh is adjusted according to the actual refresh rate, and the adjusted first row scanning duration is obtained, wherein the first row scanning duration causes the refresh rate corresponding to the refresh to be adjusted to the first refresh rate.

8. The method according to claim 1, characterized in that The method further comprises: If the first refresh rate can divide the base frequency, then in the porch area corresponding to the first refresh rate, the reference pulse number is replicated once or multiple times for the EM signal; At the first refresh rate, refreshing the screen of the display device according to the first refresh rate; and, The screen of the display device is turned on or off according to the reference pulse number corresponding to the scanning area of ​​the first refresh rate and the copied reference pulse number corresponding to the porch area.

9. The method according to any one of claims 1 to 5, characterized in that Refreshing the screen of the display device according to the actual refresh rate specifically includes: According to the actual refresh rate, the operation of refreshing the screen of the display device is performed only in the scanning area.

10. A display device, characterized in that: include: Organic light-emitting semiconductor OLED screen; one or more processors; one or more memories; The one or more memories store one or more computer programs, and the one or more computer programs include instructions. When the instructions are executed by the one or more processors, the display device performs the method according to any one of claims 1 to 9.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable program instructions, which, when executed on a computer, enable the computer to perform the method according to any one of claims 1 to 9.

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