Method of high-frequency pwm dimming and display device

Abstract

The application provides a high-frequency PWM dimming method and display device, and relates to the technical field of display. The method sets 120Hz refresh rate as a base frequency, sets 32 pulses as a reference pulse number, sets 3840Hz PWM specification as a target, sets the reference pulse number as an EM signal parameter for controlling the bright-dark alternation of an OLED screen in a scanning area; in a porch area, a non-integer result obtained by dividing the refresh rate 90Hz by the target PWM frequency 3840Hz is acquired first; then, the result is rounded, and an integer pulse number corresponding to the porch area is acquired according to the difference between the rounding result and the reference pulse number; finally, the actual refresh rate is reversely set according to the target PWM frequency, the pulse number of the porch area and the reference pulse number, so that the dimming scheme of 3840Hz PWM specification is realized at the 90Hz gear.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a high-frequency PWM dimming method and display device. BACKGROUND

[0002] Since the organic electroluminescence display (OLED) screen has been popularized in the mobile phone industry, the progress of screen display effect has been obvious to all, such as high refresh rate, low blue light, high dynamic range imaging (HDR), etc., which have brought better screen viewing experience to users.

[0003] However, due to the OLED current-driven light-emitting principle and characteristics, when the corresponding current is very small at low brightness and low gray scale, it will cause serious problems such as poor picture color and brightness uniformity, color cast and mura. In order to solve this problem, one way currently adopted in the industry is to use pulse width modulation (PWM) to dim the OLED screen at low brightness display, and use direct current (DC) to dim the OLED screen at high brightness display. The principle of PWM dimming is mainly to use the visual persistence characteristics of the human eye by constantly turning on and off the screen to achieve the effect of reducing the perceived screen brightness of the user. However, since the essence of PWM dimming is the constant on-off alternation, when the user watches the screen for a long time, low-frequency PWM dimming may have a bad effect on the human eye. In view of the shortcomings of low-frequency PWM, some high-frequency PWM dimming schemes have been developed in the industry.

[0004] Generally, the higher the frequency of PWM, the smaller the impact 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

[0005] The embodiments of the present application provide a high-frequency PWM dimming method, which provides a 3840Hz PWM specification dimming scheme to reduce the impact of screen flicker on the human eye and improve the user's screen viewing experience.

[0006] The method for high-frequency PWM dimming provided in the application, at a refresh rate of 90Hz, first takes a refresh rate of 120Hz as a base frequency, takes 32 pulses as a reference pulse number corresponding to the base frequency, takes a PWM specification of 3840Hz as a target, sets the reference pulse number corresponding to the base frequency as an EM signal parameter for controlling the bright-dark alternation of an OLED screen in a scanning area; and in a porch area, first obtains a result after the refresh rate of 90Hz is divided by the target PWM frequency of 3840Hz, which is 42.67 pulses, a non-integer; then, takes 42.67 pulses to the nearest integer to obtain 43 pulses or 42 pulses; then, according to the difference between the result of taking to the nearest integer and the reference pulse number, obtains an 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 sets an actual refresh rate close to 90Hz, so as to realize a dimming scheme of 3840Hz PWM specification at a 90Hz gear. At the same time, the dimming scheme of 3840Hz PWM specification can also be applied to a full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz and 90Hz. Specifically:

[0007] In a first aspect, a method for high-frequency PWM dimming is provided, applied to a display device, comprising:

[0008] setting a target refresh rate as a base frequency, and setting an EM signal pulse number corresponding to the base frequency for brightness control as a reference pulse number;

[0009] in a scanning area of a first refresh rate frame period, setting the EM signal pulse number corresponding to the scanning area as the reference pulse number, wherein the time length of the scanning area is the same as the time length of the base frequency frame period;

[0010] in a first porch area corresponding to a second refresh rate, according to a target pulse width modulation (PWM) frequency, a PWM frequency corresponding to the scanning area and the second refresh rate, setting a first EM signal pulse number corresponding to the first porch area, wherein the second refresh rate is a refresh rate in the first refresh rate that cannot be evenly divided by the base frequency, and the first EM signal pulse number is an integer;

[0011] according to the target PWM frequency, the reference pulse number and the first EM signal pulse number, reversely obtaining an actual refresh rate corresponding to a second refresh rate gear;

[0012] refreshing the screen of the display device according to the actual refresh rate at the second refresh rate gear; and

[0013] The screen of the display device is lit up or turned off according to the number of reference pulses corresponding to the scanning area at the second refresh rate and the number of first EM signal pulses corresponding to the first porch area.

[0014] In an implementation, the target refresh rate can be 120Hz, and the number of reference pulses (i.e., the number of reference pulses or the number of reference EM signal parameters) can be 32 pulses.

[0015] In an implementation, the first refresh rate can refer to a commonly used refresh rate, such as 90Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, etc. The first refresh rate can be different from the base frequency, and the first refresh rate can be less than the base frequency.

[0016] In an implementation, the frame period refers to the time length of each frame of image displayed on the screen during the screen refresh process.

[0017] In combination with the first aspect, in some implementations of the first aspect, the first porch area corresponding to the second refresh rate is set according to the target PWM frequency, the PWM frequency corresponding to the scanning area, and the second refresh rate, and the number of first EM signal pulses corresponding to the first porch area is specifically set as follows:

[0018] A first result obtained by dividing the second refresh rate by the target PWM frequency is obtained, and the first result is a non-integer;

[0019] According to the first result, a first integer closest to the first result is obtained;

[0020] The number of first EM signal pulses corresponding to the first porch area is set according to the first integer.

[0021] In combination with the first aspect, in some implementations of the first aspect, the first porch area corresponding to the second refresh rate is set according to the target PWM frequency, the PWM frequency corresponding to the scanning area, and the second refresh rate, and the number of first EM signal pulses corresponding to the first porch area is specifically set as follows:

[0022] A first difference between the target PWM frequency and the PWM frequency corresponding to the scanning area is obtained;

[0023] A first result obtained by dividing the second refresh rate by the first difference is calculated, and the first result is a non-integer;

[0024] According to the first result, a first integer closest to the first result is obtained;

[0025] The number of first EM signal pulses corresponding to the first porch area is set according to the first integer.

[0026] With reference to 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.

[0027] With reference to the first aspect, in some implementations of the first aspect, the first porch area corresponding to the second refresh rate is configured according to the target PWM frequency, the PWM frequency corresponding to the scanning area, and the second refresh rate, and specifically includes:

[0028] obtaining a first result obtained by dividing the second refresh rate by the target PWM frequency, the first result being a non-integer;

[0029] obtaining a second integer second-closest to the first result according to the first result;

[0030] configuring the first EM signal pulse number corresponding to the first porch area according to the second integer.

[0031] With reference to the first aspect, in some implementations of the first aspect, the first porch area corresponding to the second refresh rate is configured according to the target PWM frequency, the PWM frequency corresponding to the scanning area, and the second refresh rate, and specifically includes:

[0032] obtaining a first difference between the target PWM frequency and the PWM frequency corresponding to the scanning area;

[0033] calculating a first result obtained by dividing the second refresh rate by the first difference, the first result being a non-integer;

[0034] obtaining a second integer second-closest to the first result according to the first result;

[0035] configuring the first EM signal pulse number corresponding to the first porch area according to the second integer.

[0036] With reference to 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 second integer is 10 pulses, and the actual refresh rate is 91.4 Hz.

[0037] With reference to the first aspect, in some implementations of the first aspect, the actual refresh rate corresponding to the second refresh rate is reversely obtained according to the target PWM frequency, the reference pulse number, and the first EM signal pulse number, and specifically includes:

[0038] performing a summation calculation on the reference pulse number and the first EM signal pulse number to obtain a second result;

[0039] obtaining a third result after the second result is divided by the target PWM frequency, the third result being an actual refresh rate corresponding to the second refresh rate level.

[0040] With reference to the first aspect, in some implementations of the first aspect, the actual refresh rate corresponding to the second refresh rate level is obtained in a Long-V mode, and the method further includes:

[0041] in the Long-H mode, adjusting a time length of scanning each row of pixel points according to the actual refresh rate, and obtaining an adjusted first row scanning time length, wherein the first row scanning time length causes the refresh rate corresponding to the refresh to be adjusted to the second refresh rate.

[0042] According to the method provided by the present implementation, by adjusting the scanning time length of each row of pixel points at the actual refresh rate in the Long-H mode, a precise 90Hz refresh rate is obtained, which can realize a dimming scheme of 3840Hz PWM specification (actually 3870Hz PWM specification) at a precise 90Hz, and further realize the application of the 3840Hz PWM specification dimming scheme to the full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0043] With reference to the first aspect, in some implementations of the first aspect, the method further includes:

[0044] in a second porch area corresponding to a third refresh rate, copying the reference pulse number one or more times, wherein the third refresh rate is a refresh rate in the first refresh rate that can divide the base frequency;

[0045] refreshing the screen of the display device at the third refresh rate; and

[0046] turning on or 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 copied reference pulse number corresponding to the second porch area.

[0047] With reference to the first aspect, in some implementations of the first aspect, the method further includes:

[0048] The operation of refreshing the screen of the display device is only performed in the scanning area.

[0049] Secondly, a display device is provided, comprising:

[0050] organic light emitting diode (OLED) screen;

[0051] one or more processors;

[0052] one or more memories;

[0053] The one or more memories store one or more computer programs comprising instructions that, when executed by the one or more processors, cause the display device to perform the method of any one of the preceding first aspects.

[0054] In a third aspect, a computer-readable storage medium is provided, which stores computer executable program instructions, which, when executed on a computer, cause the computer to perform the method of any one of the preceding first aspects.

[0055] In a fourth aspect, a computer program product is provided, which comprises computer program code, which, when executed on a computer, causes the computer to perform the method of any one of the preceding first aspects. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 A schematic diagram of independently setting the number of pulses under a 2160Hz PWM specification for a 120Hz refresh rate is provided for the embodiments of the present application.

[0057] Figure 2 A structural schematic diagram of an OLED pixel driving circuit is provided for the embodiments of the present application.

[0058] Figure 3 A schematic diagram of the timing principle under a 90Hz refresh rate LongV mode and Long-H mode is provided for the embodiments of the present application.

[0059] Figure 4 A schematic diagram of the timing principle under a 90Hz refresh rate LongV mode is provided for the embodiments of the present application.

[0060] Figure 5 A schematic diagram of a dimming scheme corresponding to a 3840Hz PWM under a 89.3Hz refresh rate is provided for the embodiments of the present application.

[0061] Figure 6 A schematic diagram of a dimming scheme corresponding to a 3840Hz PWM under a 91.4Hz refresh rate is provided for the embodiments of the present application.

[0062] Figure 7A schematic diagram of the Long-V mode after the refresh rate of the reverse setting is determined to be 89.3Hz, and the row scanning time is modified on the basis of 89.3Hz.

[0063] Figure 8 A schematic diagram of the Long-V mode after the refresh rate of the reverse setting is determined to be 91.4Hz, and the row scanning time is modified on the basis of 91.4Hz.

[0064] Figure 9 A schematic flow chart of a method of high-frequency PWM dimming provided by an embodiment of the present application.

[0065] Figure 10 A schematic flow chart of another method of high-frequency PWM dimming provided by an embodiment of the present application.

[0066] Figure 11 A structural schematic diagram of a display device 100 provided by an embodiment of the present application.

[0067] Figure 12 A software structural block diagram of a display device 100 provided by an embodiment of the present application. DETAILED DESCRIPTION

[0068] It should be noted that the terms used in the implementation 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, " / " represents the meaning of or, for example, A / B can represent A or B; "and / or" in this paper is only a description of the association relationship of the associated obstacles, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B 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" means one, two or more than two.

[0069] Hereinafter, the terms "first" and "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the "first" and "second" features can explicitly or implicitly include one or more features.

[0070] Reference to "one embodiment" or "an embodiment" or "some embodiments" or "one specific embodiment" or "some specific embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" or "in some embodiments" in various places in the specification are not necessarily all referring to the same embodiment, although it can. The terms "including," "comprising," "having" and variations thereof are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "coupled" and "connected" and variations thereof are intended to encompass a connection between two members, although the connection does not have to be direct.

[0071] The technical solutions of the present application will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described in some embodiments.

[0072] In view of the shortcomings of the traditional low-frequency PWM dimming scheme, a 2160Hz high-frequency PWM (hereinafter referred to as 2160Hz PWM specification) dimming scheme has been developed in the industry. When using the 2160Hz PWM specification dimming, in order to achieve consistent PWM frequency (2160Hz) at different refresh rates, the pulse number of the emission (EM) signal needs to be accurately set.

[0073] For example, in order to achieve 2160Hz PWM specification, two ways can be mainly used to set: way (1), set the pulse number corresponding to different refresh rates separately. Way (2), set a refresh rate as the base frequency (such as 120Hz), and set the pulse number corresponding to the base frequency as the reference pulse number (such as 18 pulse of 120Hz), and then the pulse number corresponding to other refresh rates is expanded by n times according to the reference pulse number, and / or the array gate driver on array (GOA) signal parameter is expanded by n times according to the reference pulse number.

[0074] It should be noted that the pulse number referred to in the embodiments of the present application can refer to the pulse number of the EM signal corresponding to one frame for lighting or extinguishing the screen. In the embodiments of the present application, the pulse number can also be described as the EM driving pulse number or the EM signal parameter. It should also be noted that the PWM frequency is equal to the product of the refresh rate and the EM pulse number in value, and the units of the PWM frequency and the refresh rate are both Hz.

[0075] For the above-mentioned way (1), please refer to Figure 1To realize 2160Hz PWM specification, for 120Hz refresh rate, the pulse number can be independently set to 18pulse (i.e. the result of 120Hz divided by 2160Hz), and the pulse waveform of 2160Hz PWM in this case can be referred to the waveform corresponding to 18pulse-PWM in FIG. 18. Figure 1 For 60Hz refresh rate, the corresponding pulse number can be independently set to 36pulse (i.e. the result of 60Hz divided by 2160Hz), and the pulse waveform of 2160Hz PWM in this case can be referred to the waveform corresponding to 36pulse-PWM in FIG. 19. Figure 1 For 90Hz refresh rate, the corresponding pulse number can be independently set to 24pulse (i.e. the result of 90Hz divided by 2160Hz), and the pulse waveform of 2160Hz PWM in this case can be referred to the waveform corresponding to 36pulse-PWM in FIG. 20. Figure 1

[0076] The above-mentioned manner (1) can realize 2160Hz PWM specification under different refresh rates (120Hz, 60Hz, 90Hz) by independently setting the corresponding pulse number for different refresh rates.

[0077] For the above-mentioned manner (2), please continue to refer to Figure 1 To realize 2160Hz PWM specification, 120Hz refresh rate is set as the base frequency, and 18pulse corresponding to the base frequency is set as the reference pulse number. Then, the pulse number corresponding to 60Hz refresh rate and 90Hz refresh rate is set based on the reference pulse number according to the multiple relationship between the refresh rate and the base frequency. Specifically:

[0078] For 60Hz refresh rate, since the result of 60Hz divided by 120Hz is 2, the pulse number corresponding to 60Hz refresh rate can be the reference pulse number after 2 times expansion. At this time, under 60Hz refresh rate, the reference pulse number (i.e. 18pulse) can be directly copied in the scanning area for dimming, and the reference pulse number is completely repeated once again in the porch area (or called blanking area) after scanning for dimming.

[0079] ​For 90Hz refresh rate, since 90Hz cannot be divided by 120Hz, and the pulse number needs to be an integer, the pulse number corresponding to 90Hz refresh rate cannot be obtained by expanding the reference pulse number by an integer multiple. At this time, under 90Hz refresh rate, although it can be set to directly copy the reference pulse number (i.e. 18 pulse) in the scanning area for dimming, however, in the porch area after scanning is completed, the reference pulse number cannot be completely copied. For this, 90Hz refresh rate can be separately set a group of pulse numbers, such as 24 pulse, and the pulse width can be different from that of 120Hz or 60Hz.

[0080] In order to further improve the user's visual experience and make the screen of the display device more eye-friendly, the application proposes a 3840Hz high-frequency PWM (hereinafter referred to as 3840Hz PWM specification) dimming scheme. In combination with the setting method of the above-mentioned 2160Hz PWM specification, if you want to achieve 3840Hz PWM specification, you can also try two ways: way (1), separately set the pulse number corresponding to different refresh rates, such as setting the pulse number corresponding to 120Hz refresh rate to 32, and setting the pulse number corresponding to 60Hz refresh rate to 64; way (2), set a refresh rate as the base frequency (such as 120Hz), and set the pulse number corresponding to the base frequency as the reference pulse number (such as 32 pulse of 120Hz), and then expand the pulse number corresponding to other refresh rates by n times according to the reference pulse number, and / or expand the GOA signal parameter by n times according to the reference pulse number. For example, under 60Hz refresh rate, the corresponding pulse number can be expanded by 2 times according to the reference pulse number, that is, the reference pulse number is completely copied once in the scanning area and the porch area, and the pulse number of each area is 32.

[0081] However, it is worth noting that if the target PWM frequency is 3840Hz, then for 90Hz refresh rate, the above-mentioned setting method of 2160Hz PWM specification cannot be directly reused. On the one hand, if the pulse number corresponding to 90Hz refresh rate is separately set, the set pulse number is about 43 pulse (i.e. the result of 90Hz divided by 3840Hz), but the current integrated circuit (IC) usually only supports independent setting of no more than 32 pulse due to specification limitation, so this way cannot realize 3840Hz PWM specification under 90Hz refresh rate. On the other hand, since 90Hz cannot be divided by 120Hz, the reference pulse number (i.e. 32 pulse of 120Hz) cannot be completely copied in the porch area, so this way also cannot realize 3840Hz PWM specification under 90Hz refresh rate.

[0082] 90Hz is a common refresh rate of display devices such as mobile phones, tablets, etc., and the above problems cause the dimming scheme of the 3840Hz PWM specification to be unable to be applied under the 90Hz refresh rate. That is, the 3840Hz PWM specification cannot cover the commonly used full frame rate range, which will greatly affect the user's experience of using the display device.

[0083] Therefore, the embodiment of the present application provides a high-frequency PWM dimming method. Under the 90Hz refresh rate, the method first takes 120Hz refresh rate as the base frequency, takes 32pulse as the reference pulse number corresponding to the base frequency, and takes the 3840Hz PWM specification as the target. Then, the non-integer result obtained by dividing 90Hz by 3840Hz is obtained, and the non-integer result is rounded to obtain the rounding result 43 or 42. After that, according to the difference between the rounding result and the reference pulse number, the pulse number of the porch area under the 90Hz refresh rate is obtained, and 91.4Hz or 89.3Hz close to 90Hz is obtained reversely according to the target PWM frequency and the rounding result (or the sum of the reference pulse number and the pulse number of the porch area) to be regarded as (or set as) the 90Hz gear, so as to realize the 3840Hz PWM specification under the 90Hz refresh rate gear, and further achieve the 3840Hz PWM dimming scheme of the full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0084] In order to better understand the high-frequency PWM dimming method provided by the embodiment of the present application, the principle of dimming OLED screen by using PWM mode is introduced below in combination with the drawings.

[0085] First of all, it should be noted that OLED is a current type organic light emitting device, which is a phenomenon of light emission by injection and recombination of carriers, and the light emission intensity is proportional to the injected current. Under the action of an electric field, holes generated at the anode and electrons generated at the cathode will move and be 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, thereby exciting light emitting molecules to finally produce visible light. That is, the OLED panel is a self-luminous product, which does not need a backlight and can emit light by itself. The display can be completed by controlling the light emission brightness of different pixel points to form different images.

[0086] OLED mainly includes four parts, which are driving IC, battery, display area and pixel driving circuit. Among them, the driving IC is the core part of OLED display, which controls the switching and brightness of the display screen; the battery is used to power the OLED; the display area is composed of the OLED screen, which can be divided into a plurality of pixel points; the pixel driving circuit is mainly used to transmit signals between the driving IC and the display area.

[0087] The pixel driving circuit in the OLED can include a gate on array (GOA) circuit and an EM circuit, and the two parts of the circuit can respectively complete different display functions under the control of the driving IC.

[0088] The GOA circuit is a repeated circuit unit located on both sides of the OLED panel, which is used to transmit GOA signals under the control of the driving IC. The GOA signal is a signal for controlling the gate scanning, which can control the pixel points in the OLED screen (or in the plane) to open row by row, and write the display signals into the pixel capacitance in the screen row by row. Through timing configuration, the GOA signal can also control the scanning time of each row of pixel points and the porch area time length corresponding to each frame of image.

[0089] The EM circuit is used to transmit EM signals under the control of the driving IC. The EM signal is a signal for controlling the lighting of the OLED. For each pixel point in the OLED screen, after charging is completed, the thin film transistor (TFT) analog switch T3 in the driving circuit will be in the default open state, at this time, the T3 performs the "open-close-open" operation according to the set frequency through the EM signal, which can make the pixel points in the OLED screen alternately bright and dark (that is, the pixel points correspondingly switch between "lighting-off-lighting" states).

[0090] It should be noted that based on the feature that PWM dimming can make the pixel points bright and dark alternately, the user can perceive the reduction of the brightness of the OLED screen. And this feature is one of the obvious differences between PWM dimming and direct current (DC) dimming. When the DC dimming, the EM signal will always instruct the T3 to be in the open state, and the pixel points will not appear in the bright and dark alternating state.

[0091] For example, as shown in Figure 2 , it is a structure diagram of an OLED pixel driving circuit provided by an embodiment of the present application.

[0092] The pixel driving circuit is used to drive the light emitting element OLED. As shown in Figure 2 , the pixel driving circuit provided by the embodiment of the present application comprises:

[0093] The EM signal end is used to provide a control signal (EM signal) for lighting.

[0094] The first switch unit 310 has an input end connected to the second power supply line ELVDD, a control end connected to the EM signal end, and an output end connected to the first intermediate node q.

[0095] 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, and an output end connected to one end of the light-emitting element OLED, and the other end of the light-emitting element OLED is connected to the first power supply line ELVSS. The driving unit 320 may, for example, specifically include a TFT T3 transistor and another thin-film transistor switch unit T4. For each pixel point, after charging is completed, the driving TFT T3 transistor is always in an open state, and at this time, the lighting or extinguishing of the OLED screen is controlled by the EM signal, and the OLED screen is in a bright-dark alternating state (actually, the pixel points in the OLED panel are in a bright-dark alternating state, that is, the pixel points are switched between the "lighting-extinguishing-lighting" states correspondingly). For example, the so-called DC dimming refers to that the EM is always in an open state (low level); and the PWM dimming refers to that the EM is adjusted in accordance with a set frequency to be open-close-open.

[0096] 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.

[0097] The second switch unit 340 has an input end connected to the reference signal line Ref, a control end connected to the second-stage scan signal line S(n+1), and an output end connected to the second intermediate node p.

[0098] The charging control unit 350 has a first input end connected to the reference signal line Ref, a second input end connected to the data line Data, a control end connected to the first-stage scan signal S(n) (or the Reset line), a first output end connected to the second intermediate node p, and a second output end connected to the third intermediate node r.

[0099] The storage unit 360 (that is, 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.

[0100] In the first operation stage of the pixel driving circuit, under the control of the EM signal output from the EM signal end, the first switch unit 310 turns on the second power supply line ELVDD and the first intermediate node q. Under the control of the first scan signal Vs(n) output from the first-stage scan signal line S(n), the charging unit 350 turns on the reference signal line Ref and the second intermediate node p, so as to charge the storage unit 360 (Cst) connected to the first intermediate node q and the second intermediate node p, and make it store a voltage V=V ELDD-V Ref wherein, V ELDD represents the potential of the second power line ELVDD, V Ref represents the potential of the reference signal line Ref.

[0101] In the second operation stage of the pixel driving circuit, the second switch unit 340 turns on the reference signal line Ref and the second intermediate node p under the control of the second stage scan signal Vs(n+1) output by the second stage scan signal line S(n+1). At the same time, the first switch unit 310 is turned off due to the EM signal, and the first storage unit 360 is self-discharged by the driving unit 320, so that the first storage unit 360 stores the charging voltage related to the data voltage and the threshold voltage of the driving unit.

[0102] In the third operation stage of the pixel driving circuit, the third switch unit 330 turns on the third intermediate node r and the second intermediate node p under the control of the third stage scan signal Vs(n+2) output by the third stage scan signal line S(n+2) (i.e. Gate line), so that the second storage unit 370 (not shown) is discharged, i.e. the voltage difference between the two ends of the second storage unit becomes zero. Figure 2

[0103] In the driving stage of the pixel driving circuit, the first switch unit 310 turns on the second power point ELVDD and the first intermediate node q under the control of the EM signal output by the EM signal line, so that the voltage difference between the control end and the input end of the driving unit 320 is equal to the voltage stored by the first storage unit and the second storage unit. Since the voltage difference between the two ends of the second storage unit is zero, the driving current provided by the driving unit to the light-emitting element OLED is independent of the threshold voltage.

[0104] It should be understood that the EM circuit is controlled by the driving IC to transmit the EM signal. The EM signal is used to control the pixel points in the OLED screen to light up or turn off. Based on the feature that the PWM dimming can make the pixel points light up and turn off alternately, the user can perceive the brightness reduction of the OLED screen. This feature is one of the obvious differences between PWM dimming and DC dimming. When DC dimming, the EM signal will always instruct T3 to be in the on state, and the pixel points will not appear in the light-off alternating state.

[0105] It should be further explained that for the refresh rate, the screen displays static images one by one, and the dynamic images are obtained by continuously refreshing them. Within 1 second, the screen refreshes several static images, which indicates the refresh rate. Generally, the refresh rate of ordinary display devices is 60 Hz, and many display devices have adapted a refresh rate of 90 Hz or even 120 Hz. The most intuitive feeling of high refresh rate is that the picture is smoother.

[0106] ​When refreshing an image, a frame of image includes a large number of pixels. For example, for an image including more than 400,000 pixels, it is obviously impossible to simultaneously transmit information of each pixel point through more than 400,000 channels. Therefore, image refreshing actually converts information of each pixel point in the image into an electrical signal according to a certain spatial order (for example, from left to right in each row, and then from top to bottom), and transmits the electrical signal according to a time order. In this way, the change of the image with space and time is converted into the change of the electrical signal with time. The signal for controlling the scanning of the pixel point is also the GOA signal. Through timing configuration, the driving IC in the display device can also control the scanning time of each row and the porch time length of each frame through the GOA signal.

[0107] The pixel driving process involved in the PWM dimming process and the image refreshing principle are introduced above in combination with the pixel driving circuit. The specific implementation process of the high-frequency PWM dimming method provided by the embodiments of the present application is introduced below in combination with the accompanying drawings.

[0108] It should be noted that the high-frequency PWM dimming method provided by the embodiments of the present application can adjust the frame rate through a long vertical (Long-V) mode and a long horizontal (Long-H) mode. For example, as shown in Figure 3 , it is a schematic diagram of the timing principle in a 90Hz refresh rate Long-V mode and a Long-H mode provided by the embodiments of the present application.

[0109] As shown in Figure 3 , under a 120 refresh rate (base frequency), the OLED screen can be refreshed 120 times in 1s, that is, the frame period corresponding to each frame of image is about 8.33ms. In each frame period, the driving IC scans the pixel points in the OLED screen from left to right and from top to bottom through the GOA signal (that is, the gate signal) to sequentially display each pixel point of the OLED screen. For example, taking a resolution of 1080x2800 as an example, the driving IC needs to scan 2800 rows of pixel points in the frame period, so in one frame period, the driving IC starts from the first row, scans the pixel points from left to right, then scans the second row, the third row, …, the 2800th row in the same way, obtains each pixel point of the frame of image, and then performs scanning in the next frame period.

[0110] The refresh process at 90Hz is similar to that at 120Hz, also employing the progressive scan pixel method described above. During image pixel scanning, the driver IC can also output a vertical synchronizing signal (VSYNC) and a horizontal synchronizing signal (HSYNC). (The HSYNC signal...) Figure 3 (Not shown). The VSYNC signal controls the start of scanning a frame of image pixels; the HSYNC signal controls the start of scanning a row of pixels within a frame of image.

[0111] Combination Figure 3 and Figure 4 As shown, in the method provided in this application embodiment, at a refresh rate of 90Hz, two pixel scanning modes can be used, namely... Figure 3 The diagram shows the 90Hz Long-V mode and the 90Hz Long-H mode. In the 90Hz Long-V mode, there is a short VFP duration before a VSYNC signal and a short VBP duration after the VSYNC signal. The actual scanning of a frame begins after the VBP duration. In other words, based on VSYNC, the short duration before VSYNC is VFP, and the short duration after VSYNC is VBP; both durations are included within the EM duration. Specifically, before the VSYNC signal, the VFP duration is waited at the end of the previous frame's frame period; after the VSYNC signal, the VBP duration is waited at the beginning of the next frame's frame period. Then, under the control of the GOA signal, the pixels of the next frame are actually scanned.

[0112] The Data signal covers the actual scanned image pixels for the duration of the scan, while the EM signal covers both the scan area and the porch area, meaning the EM signal covers the entire frame period.

[0113] The duration of the porch region within a frame period can be considered as the sum of the VBP duration, VFP duration, and VSYNC signal duration. Optionally, considering that the VSYNC signal duration is extremely short, in some cases, the duration of the porch region can also be considered as the sum of the VBP duration and VFP duration, while ignoring the duration of the VSYNC signal.

[0114] It should be noted that, for ease of understanding, the accompanying drawings corresponding to the embodiments of this application clearly depict the VSYNC signal pulse waveform. However, in practical applications, the duration of the VSYNC signal is extremely short. In some cases, the porch region can be ignored or not ignored as needed.

[0115] It also needs to be explained that the corresponding drawings of the embodiments of the present application are only schematic, wherein the number of pulses of EM signals, refresh rate, etc. are not embodied in accurate values, but only give a schematic display, thus the refresh rate, the number of pulses of EM signals, etc. displayed in the drawings are not as a limitation on the embodiments of the present application. In addition, the time length shown in the drawings corresponding to the embodiments of the present application (including the time length of the scanning area of 120Hz and 90Hz refresh rate, the time length of the porch area of 120Hz and 90Hz refresh rate, the time length corresponding to the data signal and EM (PWM) signal, and the scanning time length and porch time length in 90Hz Long-H mode, etc.) are all examples, and do not constitute a specific limitation on the embodiments of the present application.

[0116] The driving IC can also control the lighting or extinguishing of the OLED panel through the EM signal, thereby controlling the brightness (or screen display brightness) of the pixel points of the frame image. 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 (i.e. the result after 120Hz divides 3840Hz). That is, under the 120Hz refresh rate, the OLED screen will be alternately lit and extinguished at a frequency of 32 pulses / 1s within a frame period.

[0117] Under the 90Hz refresh rate, the OLED screen can refresh 90 times in 1s, that is, the frame period corresponding to each frame image is about 11.1ms. In each frame period, the driving IC will scan the pixel points in the OLED screen from left to right and from top to bottom row by row through the GOA signal, sequentially display one by one of the pixel points of the OLED screen, and then scan in the next frame period. In the process of scanning the image pixel points, the driving IC can first control the lighting or extinguishing of the OLED screen according to the reference pulse number (i.e. 32 pulses) of the base frequency (120Hz). Since the pixel points to be scanned are the same under the 90Hz refresh rate or the 120Hz refresh rate, under the 90Hz refresh rate, only the same frame period (about 8.33ms, hereinafter 8.33ms represents the frame period time length of the 120Hz refresh rate) as the 120Hz can be used to scan the pixel points in the OLED screen, and the remaining frame time (i.e. the frame period corresponding to the 120Hz refresh rate minus the frame period corresponding to the 90Hz, the result is about 0.28ms) is the porch area. In the porch area, the driving IC will not continue to scan the pixel points 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 phenomenon may occur.

[0118] How to determine the pulse number of the porch area under the 90Hz refresh rate? The embodiment of the present application can calculate the pulse number in the following manner: first, obtain the result of 90Hz divided by the target PWM frequency, which can be obtained by the following formula (1-1); then, take the two integers closest to the result, that is, take the integer closest to it and / or the second closest integer, and the result after rounding is 43Hz or 42Hz; then, obtain the difference between the taken integer and the reference pulse number, which is the pulse number set for the porch area under the 90Hz refresh rate, wherein the difference can be obtained by the following formula (1-2) or formula (1-3)

[0119] (1-1)

[0120] (1-2)

[0121] (1-3)

[0122] After obtaining the pulse number corresponding to the porch area, the actual refresh rate can be deduced, and then the refresh rate is set in reverse so that the frequency of the PWM reaches 3840Hz.

[0123] Alternatively, the embodiment of the present application can also calculate the pulse number in the following manner: first, since in 8.33ms, the OLED has been alternately turned on and off according to 32 pulses, at this time, the distance from the target 3840Hz PWM specification is still 960Hz (this result can be calculated by the following formula (1-4)), so theoretically the pulse number set in the porch area can be 10.67 pulses (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 10.67 pulses, 10 pulses and 11 pulses, can be taken.

[0124] (1-4)

[0125] (1-5)

[0126] Set 10 pulses or 11 pulses for the porch area corresponding to the 90Hz refresh rate respectively, and obtain the total pulse number in one frame period under the 90Hz refresh rate as 42 pulses or 43 pulses respectively, which can be obtained according to the following formula (1-6) and formula (1-7) respectively.

[0127] (1-6)

[0128] (1-7)

[0129] After the pulse number corresponding to the porch area is obtained, the actual refresh rate can be deduced reversely, and then the refresh rate is reversely set so that the frequency of the PWM reaches 3840Hz. It should be understood that the result of the reversely set refresh rate will be different if the set pulse number is different. Therefore, based on different pulse numbers, the present embodiment provides multiple schemes for deducing the refresh rate. Some of the schemes will be specifically introduced below in combination with the drawings.

[0130] Scheme one: the EM signal parameter is set to 43 pulses, that is, 90Hz is set in the scanning area with the same reference pulse number (32 pulses) as 120Hz, and 11 pulses are repeated and unfolded in the porch area after 32 pulses are scanned.

[0131] For the convenience of understanding, the following embodiments all add the case corresponding to the 60Hz refresh rate as a comparison.

[0132] First, for the 60Hz refresh rate, since 60Hz can be divided by 120Hz, when the 3840Hz PWM specification is targeted, the pulse number corresponding to the 60Hz refresh rate can be expanded by 2 times based on the reference pulse number (32 pulses). Specifically, in the frame period of the 60Hz refresh rate, first, the OLED is controlled to alternate between on and off in the scanning area according to the same 32 pulse number as 120Hz, and when the scanning area is finished, the 32 pulse number of 120Hz is completely copied in the porch area.

[0133] It should be noted that the end of the scanning area indicates that the driving IC has finished scanning the pixel points of the current frame image through the GOA signal, so in the porch area corresponding to the 60Hz refresh rate, the pixel points of the frame image do not need to be scanned repeatedly, but the EM signal still needs to control the OLED to alternate between on and off according to the set 32 pulses.

[0134] Alternatively, for the 60Hz refresh rate, if the driving IC can support 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 driving IC does not support independent setting higher than 32 pulses, the result of 64 pulses after 60Hz is divided by 3840Hz can be divided into two 32 pulses, and then the OLED is controlled to alternate between on and off according to the 32 pulses in the scanning area and the porch area.

[0135] For 90Hz refresh rate, when the corresponding EM signal parameter is set as 43pulse, the target can be 3840Hz PWM specification, and the actual refresh rate is 89.3Hz, which can be obtained according to the following formula (1-8).

[0136] (1-8)

[0137] Then, the driving IC is reversely set to refresh the OLED screen at 89.30Hz (89.3Hz) refresh rate, and the EM signal is controlled to control the OLED screen to alternate between bright and dark with 32pulse in the scanning area and 11pulse in the porch area, so as to realize the 3840Hz PWM specification dimming scheme.

[0138] For example, the corresponding 3840Hz PWM dimming scheme under 89.3Hz refresh rate can be seen from Figure 5 .

[0139] In some embodiments, in order to facilitate understanding and comparison, the frame period (about 11.20ms) corresponding to 89.3Hz refresh rate can be divided into two parts, the first part has the same time length as the frame period corresponding to 120Hz refresh rate (about 8.33ms), and the second part is the remaining time length of the frame period corresponding to 89.3Hz refresh rate (about 2.87ms). It is easy to understand that the first part is the scanning area, and the second part is the porch area.

[0140] In specific implementation, the display device can control the OLED to alternate between bright and dark according to the reference EM signal parameter 32pulse in the scanning area. After 32pulse is completed in about 8.33ms, in the porch area time length (about 2.87ms) remaining in the frame period corresponding to 89.3Hz refresh rate, the OLED is controlled to alternate between bright and dark according to the separately set EM signal parameter 11pulse.

[0141] It should be noted that the end of the scanning area indicates that the driving IC has completed the scanning of the pixel points of the current frame image through the GOA signal, so in the porch area corresponding to 89.3Hz refresh rate, the pixel points of the frame image do not need to be repeatedly scanned, but the EM signal still needs to continue to control the OLED to alternate between bright and dark according to the set 11pulse.

[0142] According to the high-frequency PWM dimming scheme provided in the embodiments of the present application, at a 90Hz refresh rate, first, 120Hz is taken as a base frequency, 32 pulses are taken as the reference pulse number corresponding to the base frequency, 3840Hz PWM specification is taken as a target, the reference pulse number corresponding to the base frequency is set in the scanning area as an EM signal parameter for controlling the bright-dark alternation of the OLED screen; and in the porch area, first, the result obtained by dividing the refresh rate 90Hz by the target PWM frequency 3840Hz is obtained, which is 42.67 pulses, a non-integer; then, 42.67 pulses is rounded to obtain 43 pulses or 42 pulses; then, according to the difference between the rounding 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 90Hz is reversely set, so that the dimming scheme of 3840Hz PWM specification can be realized at the 90Hz gear. At the same time, the dimming scheme of 3840Hz PWM specification can also be applied to the full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0143] Scheme two: the EM signal parameter is set to 42 pulses, that is, the same reference pulse number (32 pulses) as 120Hz is set in the scanning area at 90Hz, and 10 pulses are repeatedly developed in the porch area after 32 pulses are scanned.

[0144] First, for the 60Hz refresh rate, since 60Hz can be divided by 120Hz, when the 3840Hz PWM specification is taken as the target, the pulse number corresponding to the 60Hz refresh rate can be developed by 2 times based on the reference pulse number (32 pulses). Specifically, in the frame period, first, the same reference pulse number as 120Hz is used to control the bright-dark alternation of the OLED, and when 32 pulses are scanned in the scanning area, the reference pulse number of 120Hz is completely copied in the porch area.

[0145] It should be noted that the end of the scanning area indicates that the driving IC has scanned the pixel points of the current frame image through the GOA signal, so in the porch area corresponding to the 60Hz refresh rate, the repeated scanning operation on the pixel points of the frame image is not needed, but the EM signal still needs to continue to control the bright-dark alternation of the OLED according to the set 32 pulses.

[0146] Optionally, for 60Hz refresh rate, if the driving IC can support independent setting of higher than 32 pulse, the EM signal parameter corresponding to 60Hz refresh rate can be set to 64 pulse (i.e. the result of 60Hz dividing 3840Hz). Alternatively, if the driving IC does not support independent setting of higher than 32 pulse, 64 pulse can be divided into two 32 pulse according to the result of 60Hz dividing 3840Hz, and then the OLED is controlled to turn on and off alternately according to 32 pulse in the scanning area and the porch area, respectively.

[0147] For 90Hz refresh rate, when the EM signal parameter corresponding thereto is set to 42 pulse, the actual refresh rate can be deduced to be 91.4Hz according to 3840Hz PWM specification, and the result can be obtained according to the following formula (1-9).

[0148] (1-9)

[0149] Then, the driving IC is reversely set to refresh the OLED screen at 91.43Hz (or 91.4Hz) refresh rate, and the OLED screen is controlled to turn on and off alternately according to the EM signal of 32 pulse in the scanning area and 10 pulse in the porch area, so as to realize the dimming scheme of 3840Hz PWM specification.

[0150] For example, the dimming scheme of 3840Hz PWM corresponding to 91.4Hz refresh rate can be seen from FIG. 1-9. Figure 6 .

[0151] In some embodiments, for the convenience of understanding and comparison, the frame period (about 10.94ms) corresponding to 91.4Hz refresh rate can be divided into two parts, the first part has the same time length as the frame period corresponding to 120Hz refresh rate (about 8.33ms), and the second part is the time length left in the frame period corresponding to 91.4Hz refresh rate (about 2.61ms). It is easy to understand that the first part corresponds to the scanning area, and the second part corresponds to the porch area.

[0152] In specific implementation, the display device can control the OLED to turn on and off alternately according to 32 pulse in the scanning area. After 32 pulse is completed in about 8.33ms, the OLED is controlled to turn on and off alternately according to the EM signal parameter of 10 pulse in the time length (about 2.61ms) left in the frame period corresponding to 91.4Hz refresh rate.

[0153] It should be noted that the end of the scanning area indicates that the driving IC has completed the scanning of the pixel points of the current frame image through the GOA signal, so there is no need to perform repeated scanning operations on the pixel points of the frame image in the porch area corresponding to the 91.4Hz refresh rate, but the EM signal still needs to continue to control the OLED to alternate between being on and off according to the set 10pulse.

[0154] According to the high-frequency PWM dimming scheme provided in the embodiments of the present application, under the 90Hz refresh rate, first, 120Hz refresh rate is taken as the base frequency, 32pulse is taken as the reference pulse number corresponding to the base frequency, and 3840Hz PWM specification is taken as the target. The base frequency corresponding reference pulse number is set in the scanning area as the EM signal parameter for controlling the OLED screen to alternate between being on and off. In the porch area, first, the result obtained by dividing the refresh rate 90Hz by the target PWM frequency 3840Hz is obtained, which is 42.67pulse, which is a non-integer. Then, 42.67pulse is rounded to obtain 43pulse or 42pulse. Then, according to the difference between the rounding 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 90Hz is reversely set, so that the 3840Hz PWM specification dimming scheme can be realized at the 90Hz gear. At the same time, the 3840Hz PWM specification dimming scheme can also be applied to the full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0155] It should be noted that in addition to the above-mentioned scheme one and scheme two, the high-frequency PWM dimming method provided in the embodiments of the present application can also be realized by adjusting the scanning time of each row of pixel points through the clock (CLK) of the driving IC under the Long-H scanning mode, uniformly compressing the time length, or uniformly stretching the time length, so that the refresh rate is accurately realized again at 90Hz. It should be noted that each CLK signal moves to scan a pixel point, so the scanning time of each row of pixel points can be controlled by setting the CLK signal.

[0156] The following describes a way to more accurately realize 90Hz under the 3840Hz PWM specification, with reference to the accompanying drawings.

[0157] Scheme three: when the refresh rate is 89.3Hz and the EM signal parameter is 43pulse, the scanning time of each scanning row is compressed under the Long-H mode to adjust the refresh rate.

[0158] For example, as Figure 7 After the refresh rate of 89.3Hz is determined by the reverse setting of the Long-V mode, the diagram of the modified row scanning duration based on 89.3Hz is shown.

[0159] Please refer to Figure 7 The content shown in the dashed box. In some embodiments, when the refresh rate is 89.3Hz after the reverse setting in the Long-V mode, the driving IC can adjust the scanning duration of each row of pixels in the Long-H mode based on the 89.3Hz refresh rate, so that the refresh rate reaches 90Hz.

[0160] In some embodiments, in the Long-H mode, the driving IC can adjust the scanning duration of each row of pixels in each frame of image by CLK, so that if each frame of image is scanned in the Long-H mode, the scanning duration of each row of pixels can be compressed based on the scanning duration of each row of pixels at the refresh rate of 89.3Hz, that is, the scanning duration of each row of pixels is shortened, and the frame period of scanning each frame of image is also shortened, so that the refresh rate is correspondingly increased, and finally the refresh rate of 89.3Hz is increased to the accurate refresh rate of 90Hz.

[0161] Specifically, please refer to Figure 7 The gap between the two oval boxes is the gap between the duration of 3 frames of 89.3Hz refresh rate and the duration of 3 frames of 90Hz refresh rate. The gap (in duration) indicates that the frame period of 89.3Hz refresh rate is longer than that of 90Hz, and the scanning duration of each row of pixels is also longer than that of 90Hz, so by fine-tuning the scanning duration of each row of pixels, the refresh rate of 89.3Hz can be adjusted to 90Hz.

[0162] It should be noted that in this scheme, the refresh rate is adjusted from 89.3Hz to 90Hz by scanning the pixels in the Long-H mode, not in the Long-V mode. Only in the process of obtaining 90Hz, the scanning parameters (such as frame period) obtained by the Long-V mode are used. That is, the third scheme provided by the embodiments of the application uses both the Long-V mode and the Long-H mode, so the scheme can be regarded as a hybrid scheme of the Long-V mode and the Long-H mode.

[0163] It should be further noted that the process of reverse setting (or deriving) the refresh rate of 89.3Hz by the Long-V mode can be referred to the description in the above-mentioned first scheme, which will not be repeated here.

[0164] In some embodiments, when the refresh rate is adjusted to 90Hz, the frequency of the high-frequency PWM is actually 3870Hz, which can be obtained according to the following formula (1-10). For the convenience of understanding and setting, in actual application, it can be regarded as or set to 3840Hz PWM specification close to it.

[0165] (1-10)

[0166] According to the high-frequency PWM dimming scheme provided by the embodiments of the present application, under the refresh rate of 90Hz, first, take the refresh rate of 120Hz as the base frequency, take 32pulse as the reference pulse number corresponding to the base frequency, and take 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 on-off alternation of the OLED screen, and in the porch area, first, obtain the result after the refresh rate 90Hz is divided by the target PWM frequency 3840Hz. The result is 42.67pulse, which is a non-integer. Then, take 42.67pulse to the nearest integer to obtain 43pulse or 42pulse. Then, according to the difference between the integer pulse number corresponding to the porch area 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 90Hz is reversely set, so that the dimming scheme of 3840Hz PWM specification can be realized at 90Hz gear.

[0167] In addition, in the Long-H mode, by adjusting the scanning time of each row of pixel points at the actual refresh rate, the accurate 90Hz refresh rate is obtained, which can realize the dimming scheme of 3840Hz PWM specification (actually 3870Hz PWM specification) at the accurate 90Hz, and further realize the application of the dimming scheme of 3840Hz PWM specification in the full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz and 90Hz.

[0168] Scheme four: when the refresh rate is 91.4Hz and the EM signal parameter is 42pulse, the scanning time of each scanning line is compressed in the Long-H mode to adjust the refresh rate.

[0169] As shown in Figure 8 , after the reverse set refresh rate of 91.4Hz is determined for the Long-V mode, the schematic diagram after modifying the row scanning time based on 91.4Hz is shown.

[0170] Please refer to Figure 8The content shown in the dashed box. In some embodiments, when in Long-V mode, after the refresh rate is reversely set to 91.4 Hz, the driving 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.

[0171] In some embodiments, in Long-H mode, the driving IC can adjust the scanning time of each row of pixels in each frame of image through CLK, so that if each frame of image is scanned in Long-H mode, the scanning time of each row of pixels can be stretched based on the scanning time of each row of pixels at 91.4 Hz refresh rate, that is, the scanning time of each row of pixels is lengthened, and the frame period of scanning each frame of image is also lengthened, so that the refresh rate is correspondingly reduced, and the 91.4 Hz refresh rate is reduced to the accurate 90 Hz refresh rate.

[0172] Specifically, referring to Figure 8 The gap between the two oval boxes is the gap between the time length of 3 frames of 91.4 Hz refresh rate and the time length of 3 frames of 90 Hz refresh rate. The gap (in time length) indicates that the frame period of 91.4 Hz refresh rate is shorter than that of 90 Hz, and the scanning time of each row of pixels is also shorter than that of 90 Hz, so by fine-tuning the scanning time of each row of pixels, the 91.4 Hz refresh rate can be adjusted to 90 Hz refresh rate.

[0173] It should be noted that in this scheme, after the refresh rate is adjusted from 91.4 Hz to 90 Hz, the pixel scanning is performed in Long-H mode, not in Long-V mode. Only in the process of obtaining 90 Hz, the scanning parameters (such as frame period) obtained by Long-V mode at 91.4 Hz are used. That is, the scheme provided in the embodiment of the application uses both Long-V mode and Long-H mode, so the scheme can be regarded as a hybrid scheme of Long-V mode and Long-H mode.

[0174] It should be further noted that the process of reversely setting (or deriving) 91.4 Hz refresh rate through Long-V mode can be referred to the description in the above-mentioned scheme two, which will not be repeated here.

[0175] In some embodiments, after 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 the convenience of understanding and setting, optionally, in actual application, it can be regarded as or set as a 3840 Hz PWM specification close to it.

[0176] According to the high-frequency PWM dimming scheme provided in the embodiments of this application, at a refresh rate of 90Hz, a refresh rate of 120Hz is first used as the base frequency, and 32 pulses are used as the reference pulse number corresponding to the base frequency. With a target of 3840Hz PWM specification, the reference pulse number corresponding to the base frequency is set in the scanning area as the EM signal parameter controlling the on / off alternation of the OLED screen. In the porch area, the result of dividing the refresh rate of 90Hz by the target PWM frequency of 3840Hz is first obtained, which is 42.67 pulses, a non-integer value. Then, 42.67 pulses is rounded down to obtain 43 pulses or 42 pulses. Next, based on the difference between the rounded result and the reference pulse number, the integer pulse number corresponding to the porch area is obtained. Finally, based on the target PWM frequency, the pulse number corresponding to the porch area, and the reference pulse number, the actual refresh rate is set in reverse to be close to 90Hz, thereby achieving a dimming scheme that can achieve a 3840Hz PWM specification even at a 90Hz refresh rate.

[0177] Furthermore, in Long-H mode, by adjusting the scanning duration of each row of pixels at the actual refresh rate, a precise 90Hz refresh rate can be obtained. This enables a dimming scheme that achieves a 3840Hz PWM specification (actually a 3870Hz PWM specification) at a precise 90Hz. Consequently, the 3840Hz PWM specification dimming scheme can be applied to almost all commonly used refresh rates, including 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz, across the entire frame rate range.

[0178] For example, such as Figure 9 The diagram shown is a schematic flowchart of a high-frequency PWM dimming method provided in an embodiment of this application. This process can be executed by a display device and specifically includes the following steps:

[0179] S1001, set the target refresh rate to the base frequency, and set the EM signal parameters corresponding to the base frequency to the reference pulse number.

[0180] Here, the refresh rate refers to the refresh rate in Long-V mode. The target refresh rate as the base frequency can be 120Hz as described above, and the corresponding reference pulse number can be 32 pulses as described above. In this embodiment, 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 uses to control the screen of the display device to turn on or off within a unit time (1 second). The screen of the display device can include the OLED screen described above.

[0181] In some embodiments, the EM signal parameter under the 120Hz refresh rate is set to 32 pulses, and when PWM dimming is used, the frequency can reach 3840Hz.

[0182] It should be noted that the embodiments of the present application mainly take the currently commonly used 120Hz as the base frequency, and the frequency of PWM dimming is 3840Hz as the target for description, but in actual application, 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 at present or in the future, and the frequency target of PWM dimming can also be a higher frequency, and the embodiments of the present application do not limit this.

[0183] S1002, in the scanning area of the first refresh rate frame period, set the corresponding pulse number as the reference pulse number, wherein the time length of the scanning area is the same as the time length of the base frequency frame period.

[0184] In some embodiments, the first refresh rate can refer to commonly used refresh rates other than the base frequency, which are less than the base frequency, and can or can not be divisible by the base frequency. These refresh rates may, for example, include 90Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, etc.

[0185] It should be noted that in the embodiments of the present application, the frame period of the first refresh rate can be divided into a scanning area and a porch area.

[0186] The scanning area refers to the area corresponding to the period of performing scanning operation on image pixels. The scanning area is aligned with the frame period of the base frequency and has the same time length. For example, if the base frequency is 120Hz, the time length of the base frequency frame period is about 8.33ms, and if under the 120Hz refresh rate, the scanning period corresponding to a frame of image is from 00:00 to (00:00+8.33ms), then the time period of the scanning area corresponding to the first refresh rate can also be set to from 00:00 to (00:00+8.33ms), and the time length is also 8.33ms.

[0187] The porch area refers to the area after the scanning operation on the image pixels is performed. In the porch area, the pixels do not need to be scanned repeatedly, and the time length of the porch area is the time length of the frame period of the first refresh rate minus the time length of the scanning area. For more detailed introduction of the scanning area and the porch area, please refer to the related content in Figures 2 to 8

[0188] ​In some embodiments, the display device can scan the pixels of the current frame image in Long-V mode within the scanning area corresponding to the first refresh rate, 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 have been scanned. The driver IC in the display device can control the scanning of the pixels via the GOA signal.

[0189] Furthermore, within the scanning area corresponding to the first refresh rate, the display device can also control the screen to turn on or off according to the reference pulse number via the EM signal, keeping the screen in an alternating on / off state so that the user can visually perceive changes in screen brightness. For example, if the reference pulse number for a base frequency of 120Hz is 32, then within the scanning area of ​​the first refresh rate, the driver IC in the display device will control the screen to alternate on and off according to the EM signal of 32 pulses.

[0190] S1003A, in the porch area corresponding to the second refresh rate, obtains the pulse number set for the porch area based on the target PWM frequency, the PWM frequency corresponding to the scan area, and the second refresh rate. The second refresh rate is the refresh rate in the first refresh rate that cannot be divided by the base frequency.

[0191] In some embodiments, before executing step S1003A, it can be determined whether the current refresh rate is divisible by the base frequency. If it is not divisible, the process from S1003A to S1005A is executed; if it is divisible, the process jumps to execute steps S1003B and S1004B.

[0192] The pulse count set for the porch area can be calculated through the following process: (1) Calculate the number of pulses required to achieve the 3840Hz PWM specification at a 90Hz refresh rate according to the formula (1-1) shown above, that is... (2) According to Take the two nearest integers and round the result to 43 pulses or 42 pulses; (3) According to the formula (1-2) or formula (1-3) shown above, calculate the difference between the rounded result 43 pulses or 42 pulses and the base pulse number. The difference result is 11 pulses or 10 pulses, which is the pulse number set for the porch area at a refresh rate of 90Hz.

[0193] The S1004A obtains the actual refresh rate by reverse calculation based on the baseline pulse count, the pulse count set for the porch area, and the target PWM frequency.

[0194] In some embodiments, the actual refresh rate can be obtained by calculating using the following process formula (1-11).

[0195] (1-11)

[0196] Specifically, when the second refresh rate is 90Hz, and the pulse number set for the porch area is 11 pulses, the actual refresh rate can be calculated as 89.3Hz according to the above formula (1-11). When the second refresh rate is 90Hz, and the pulse number set for the porch area is 10 pulses, the actual refresh rate can be calculated as 91.4Hz according to the above formula (1-11).

[0197] It can be understood that the actual refresh rate is a frequency very close to the second refresh rate, and thus in actual application, it can be regarded as or set as the second refresh rate level. For example, 89.3Hz and / or 91.4Hz can be regarded as or set as the 90Hz level.

[0198] S1005A, refreshing the screen at the actual refresh rate in the second refresh rate level; and turning on or off the screen of the display device according to the reference pulse number corresponding to the scanning area of the second refresh rate and the pulse number corresponding to the porch area.

[0199] In some embodiments, the driving IC in the display device can refresh the screen at the actual refresh rate; and the driving IC in the display device can control the screen to turn on and off alternately by 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.

[0200] S1003B, copying the reference pulse number one or more times in the porch area corresponding to the third refresh rate, so that the EM signal covers the porch area, wherein the third refresh rate is a refresh rate in the first refresh rate that can be divided by the base frequency.

[0201] In some embodiments, before performing the step of S1003B, it can also be judged whether the current refresh rate can be divided by the base frequency. If it can be divided, the process of S1003B to S1005B is performed; if it cannot be divided, the process in steps S1003A to S1005A is jumped to perform.

[0202] It should be noted that since the time length of the scanning area of the third refresh rate is the same as the frame period of the base frequency, and the time length of the porch area is the time length left after the frame period of the third refresh rate is subtracted by the time length of the scanning area, therefore, when the third refresh rate is different, the time length of the porch area is also different, resulting in that the number of times of copying the reference pulse number in the porch area is also different.

[0203] Specifically, when the base frequency is 120Hz, the refresh rates that are integer multiples of the base frequency can include 40Hz, 30Hz, 20Hz, 10Hz, etc. in addition to 60Hz that is mainly introduced above. For example, when the third refresh rate is 60Hz, the time length of the scanning area is about 8.33ms, and the time length of the porch area is also about 8.33ms. At this time, the reference pulse number can be copied once in the corresponding porch area. That is, under the 60Hz refresh rate, 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 time length of the scanning area is about 8.33ms, and the time length of the porch area is about 1.66ms (i.e., 2*8.33ms). At this time, the reference pulse number can be copied twice in the 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. Other refresh rates that are integer multiples of the base frequency can set the EM signal parameters corresponding to the scanning area and the porch area in a similar manner as 60Hz and 40Hz. Details are not described herein.

[0204] S1004B, under the third refresh rate, refreshing the screen according to the third refresh rate; and turning on or off the screen of the display device according to the copied reference pulse number corresponding to the third refresh rate.

[0205] According to the high-frequency PWM dimming scheme provided in the embodiments of the present application, under the 90Hz refresh rate, first, 120Hz is taken as the base frequency, 32 pulses are taken as the reference pulse number corresponding to the base frequency, and 3840Hz PWM specification is taken 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 bright-dark alternation of the OLED screen. In the porch area, first, the result of dividing the refresh rate 90Hz by the target PWM frequency 3840Hz is obtained, which is about 42.67 pulses and is not an integer. Then, 42.67 pulses is rounded to obtain 43 pulses or 42 pulses. Then, according to the difference between the rounding 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 90Hz is reversely set, so that the 3840Hz PWM specification dimming scheme can be realized under the 90Hz gear. At the same time, the 3840Hz PWM specification dimming scheme can also be applied to the full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0206] Exemplarily, as shown in Figure 10 Fig. 7 is a schematic flowchart of another method for high-frequency PWM dimming provided by an embodiment of the present application. The execution subject of the flowchart can be a display device, and the flowchart specifically includes the following steps.

[0207] S1001, setting a target refresh rate as a base frequency, and setting a pulse number of an EM signal corresponding to the base frequency for brightness control as a reference pulse number. S1002, in a scanning area of a first refresh rate frame period, setting a first EM signal pulse number corresponding to the scanning area as the reference pulse number, wherein the time length of the scanning area is the same as the time length of the base frequency frame period.

[0208] S1003, in a first porch area corresponding to a second refresh rate, setting a first EM signal pulse number corresponding to the first porch area according to a target PWM frequency, a PWM frequency corresponding to the scanning area, and the second refresh rate, wherein the second refresh rate is a refresh rate that cannot be evenly divided by the base frequency in the first refresh rate, and the first EM signal pulse number is an integer.

[0209] In some embodiments, in the first porch area corresponding to the second refresh rate, the first EM signal pulse number 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 second refresh rate is divided by the target PWM frequency, the first result being a non-integer; obtaining a first integer closest to the first result according to the first result; and setting the first EM signal pulse number corresponding to the first porch area according to the first integer.

[0210] Wherein, 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.

[0211] Optionally, in the first porch area corresponding to the second refresh rate, the first EM signal pulse number 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 process can further include the following process: obtaining a first difference value of the target PWM frequency and the PWM frequency corresponding to the scanning area; calculating a first result after the second refresh rate is divided by the first difference value, the first result being a non-integer; obtaining a first integer closest to the first result according to the first result; and setting the first EM signal pulse number corresponding to the first porch area according to the first integer.

[0212] In some embodiments, according to the target PWM frequency, the PWM frequency corresponding to the scanning area, and the second refresh rate, the first EM signal pulse number corresponding to the first porch area at the second refresh rate can further include the following process: obtaining a first result after the second refresh rate is divided by the target PWM frequency, the first result being a non-integer; according to the first result, obtaining a second integer second-close to the first result; and setting the first EM signal pulse number corresponding to the first porch area according to the second integer.

[0213] In the above example, the target PWM frequency is 3840Hz, the second refresh rate is 90Hz, the fundamental frequency is 120Hz, the reference pulse number is 32pulse, the second integer is 10pulse, and the actual refresh rate is 91.4Hz.

[0214] Alternatively, according to the target PWM frequency, the PWM frequency corresponding to the scanning area, and the second refresh rate, the first EM signal pulse number corresponding to the first porch area at the second refresh rate can further include the following process: obtaining a first difference between the target PWM frequency and the PWM frequency corresponding to the scanning area; calculating a first result after the second refresh rate is divided by the first difference, the first result being a non-integer; according to the first result, obtaining a second integer second-close to the first result; and setting the first EM signal pulse number corresponding to the first porch area according to the second integer.

[0215] S1004, according to the target PWM frequency, the reference pulse number, and the first EM signal pulse number, inversely obtaining the actual refresh rate corresponding to the second refresh rate.

[0216] In some embodiments, according to the target PWM frequency, the reference pulse number, and the first EM signal pulse number, inversely obtaining the actual refresh rate corresponding to the second refresh rate can specifically include: performing a sum calculation on the reference pulse number and the first EM signal pulse number to obtain a second result; and obtaining a third result after the second result is divided by the target PWM frequency, the third result being the actual refresh rate corresponding to the second refresh rate.

[0217] S1005, refreshing the screen of the display device at the actual refresh rate at the second refresh rate; and turning on or off the screen of the display device according to the reference pulse number corresponding to the scanning area at the second refresh rate, and the first EM signal pulse number corresponding to the first porch area.

[0218] In some embodiments, the actual refresh rate corresponding to the second refresh rate level is obtained in the Long-V mode, and the method further comprises: in the Long-H mode, adjusting the time length of scanning each row of pixel points in the image according to the actual refresh rate, and obtaining an adjusted first row scanning time length, wherein the first row scanning time length causes the refresh rate corresponding to the refresh to be adjusted to the second refresh rate.

[0219] In some embodiments, the method further comprises: in a second porch area corresponding to a third refresh rate, copying the reference pulse number one or more times for the EM signal, wherein the third refresh rate is a refresh rate in the first refresh rate that is an integer multiple of the base frequency; refreshing the screen of the display device at the third refresh rate; and turning on or off the screen of the display device according to the reference pulse number corresponding to the scanning area at the third refresh rate and the copied reference pulse number corresponding to the second porch area.

[0220] In some embodiments, the method further comprises: the operation of refreshing the screen of the display device is only performed in the scanning area.

[0221] According to the high-frequency PWM dimming scheme provided in the embodiments of the present application, at a refresh rate of 90Hz, first, a refresh rate of 120Hz is taken as the base frequency, 32 pulses are taken as the reference pulse number corresponding to the base frequency, and 3840Hz PWM specifications are taken 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 on-off alternation of the OLED screen, and in the porch area, first, the result obtained by dividing the refresh rate 90Hz by the target PWM frequency 3840Hz is obtained, which 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 rounding result and the reference pulse number, an 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 90Hz is reversely set, so that the dimming scheme of 3840Hz PWM specifications can be realized at the 90Hz level.

[0222] In addition, in the Long-H mode, by adjusting the scanning time length of each row of pixel points at the actual refresh rate, a precise 90Hz refresh rate is obtained, which can realize a dimming scheme of 3840Hz PWM specifications (actually 3870Hz PWM specifications) at a precise 90Hz, and further realize the application of the dimming scheme of 3840Hz PWM specifications to the full frame rate range of almost commonly used refresh rates such as 120Hz, 60Hz, 40Hz, 30Hz, 20Hz, 10Hz, and 90Hz.

[0223] The high-frequency PWM dimming method provided by the embodiments of the present application can be applied to various types of display devices with OLED screens. For example, a mobile phone, a tablet computer, a wearable device, a notebook computer, a desktop computer, a netbook, a personal digital assistant (PDA), and the like. The embodiments of the present application do not limit the type of display device.

[0224] For example, as shown in FIG. 1, a schematic structural diagram of a display device 100 provided by the embodiments of the present application is shown. Figure 11

[0225] The display device 100 can 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 loudspeaker 170A, a receiver 170B, a microphone 170C, a headset interface 170D, a sensor module 180, a key 190, a motor 191, an indicator 192, a camera 193, a display screen 194, and a subscriber identification module (SIM) card interface 195, and the like. The sensor module 180 can include a pressure sensor 180A, a gyroscope sensor 180B, a barometric 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, and the like.

[0226] It can be understood that the structure shown in the embodiments of the present application does not constitute a specific limitation on the display device 100. In other embodiments of the present application, the display device 100 can include more or fewer components than shown, or combine certain components, or split certain components, or different component arrangements. The components shown can be implemented in hardware, software, or a combination of software and hardware.

[0227] ​The processor 110 can include one or more processing units, for example: the processor 110 can include an application processor (AP), a modem processor, a graphics processing unit (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 can be independent devices or integrated in one or more processors.

[0228] The controller can be the nerve center and command center of the display device 100. The controller can generate operation control signals according to instruction operation codes and timing signals, and complete the control of fetching and executing instructions.

[0229] The processor 110 can 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 can store instructions or data that have just been used or are frequently used by the processor 110. If the processor 110 needs to use the instructions or data again, it can directly call them from the memory. This avoids repeated access and reduces the waiting time of the processor 110, thereby improving the efficiency of the system.

[0230] In some embodiments, the processor 110 can include one or more interfaces. The interfaces can 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.

[0231] 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 can contain multiple sets of I2C bus. The processor 110 can be coupled to the touch sensor 180K, the charger, the flash, the camera 193, etc. through different I2C bus interfaces respectively. For example, the processor 110 can be coupled to the touch sensor 180K through an I2C interface, so that the processor 110 and the touch sensor 180K communicate through the I2C bus interface, and the touch function of the display device 100 is realized.

[0232] The I2S interface can be used for audio communication. In some embodiments, the processor 110 can contain multiple sets of I2S bus. The processor 110 can be coupled to the audio module 170 through the I2S bus, and communication between the processor 110 and the audio module 170 is realized. In some embodiments, the audio module 170 can deliver audio signals to the wireless communication module 160 through the I2S interface, and the function of answering a phone through a Bluetooth earphone is realized.

[0233] The PCM interface can also be used for audio communication, which samples, quantizes and encodes analog signals. In some embodiments, the audio module 170 and the wireless communication module 160 can be coupled through the PCM bus interface. In some embodiments, the audio module 170 can also deliver audio signals to the wireless communication module 160 through the PCM interface, and the function of answering a phone through a Bluetooth earphone is realized. Both the I2S interface and the PCM interface can be used for audio communication.

[0234] The UART interface is a universal serial data bus, which is used 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 usually 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, and the Bluetooth function is realized. In some embodiments, the audio module 170 can deliver audio signals to the wireless communication module 160 through the UART interface, and the function of playing music through a Bluetooth earphone is realized.

[0235] The MIPI interface can be used to connect the processor 110 and 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), and the like. In some embodiments, the processor 110 and the camera 193 communicate through the CSI interface to implement the photographing function of the display device 100. The processor 110 and the display screen 194 communicate through the DSI interface to implement the display function of the display device 100.

[0236] 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 and the camera 193, the display screen 194, the wireless communication module 160, the audio module 170, the sensor module 180, and the like. The GPIO interface can also be configured as an I2C interface, an I2S interface, a UART interface, a MIPI interface, and the like.

[0237] The USB interface 130 is an interface that conforms to the USB standard specification, and can be a Mini USB interface, a Micro USB interface, a USB Type C interface, or the like. The USB interface 130 can be used to connect a charger to charge the display device 100, or to transmit data between the display device 100 and a peripheral device. The interface can also be used to connect a headset to play audio through the headset. The interface can also be used to connect other terminals, such as AR devices, and the like.

[0238] It can be understood that the interface connection relationship between the modules shown in the embodiments of the present application is only illustrative and does not constitute a structural limitation on the display device 100. In other embodiments of the present application, the display device 100 can also use different interface connection methods or combinations of multiple interface connection methods as described in the above embodiments.

[0239] The charging management module 140 is used to receive charging input from a charger. The charger can be a wireless charger or a wired charger. In some wired charging embodiments, the charging management module 140 can receive charging input from a wired charger through the USB interface 130. In some wireless charging embodiments, the charging management module 140 can receive wireless charging input through a wireless charging coil of the display device 100. The charging management module 140 can charge the battery 142 while also providing power to the terminal through the power management module 141.

[0240] The power management module 141 is configured to connect the battery 142 and the charging management module 140 to the processor 110. The power management module 141 receives input from the battery 142 and / or the charging management module 140 to power the processor 110, the internal memory 121, the external memory, the display 194, the camera 193, the wireless communication module 160, and the like. The power management module 141 can also be configured to monitor parameters such as the battery capacity, the number of battery cycles, the battery health status (leakage, impedance), and the like. In some other embodiments, the power management module 141 can also be disposed in the processor 110. In some other embodiments, the power management module 141 and the charging management module 140 can also be disposed in the same device.

[0241] The wireless communication function of the display device 100 can be implemented by the antenna 1, the antenna 2, the mobile communication module 150, the wireless communication module 160, the modem processor, and the baseband processor, and the like.

[0242] The antenna 1 and the antenna 2 are configured to transmit and receive electromagnetic wave signals. Each antenna in the display device 100 can be configured to cover a single or multiple communication frequency bands. Different antennas can also be multiplexed to improve the utilization of the antennas. For example, the antenna 1 can be multiplexed as a diversity antenna for a wireless local area network. In some other embodiments, the antennas can be used in combination with a tuning switch.

[0243] The mobile communication module 150 can provide a solution for wireless communication including 2G / 3G / 4G / 5G and the like applied to the display device 100. The mobile communication module 150 can include at least one filter, a switch, a power amplifier, a low noise amplifier (LNA), and the like. The mobile communication module 150 can receive electromagnetic waves from the antenna 1, filter, amplify, and the like the received electromagnetic waves, and transmit the processed electromagnetic waves to the modem processor for demodulation. The mobile communication module 150 can also amplify signals modulated by the modem processor and radiate the signals as electromagnetic waves through the antenna 1. In some embodiments, at least part of the functional modules of the mobile communication module 150 can be disposed in the processor 110. In some embodiments, at least part of the functional modules of the mobile communication module 150 and at least part of the modules of the processor 110 can be disposed in the same device.

[0244] The modem processor can include a modulator and a demodulator. The modulator is configured to modulate a low frequency baseband signal to be transmitted into a medium-high frequency signal. The demodulator is configured to demodulate a 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. The low frequency baseband signal is processed by the baseband processor and then transmitted to the application processor. The application processor outputs sound signals through audio devices (not limited to the speaker 170A, the microphone 170B, etc.), or displays images or videos through the display screen 194. In some embodiments, the modem processor can be a separate device. In other embodiments, the modem processor can be independent of the processor 110 and be disposed in the same device as the mobile communication module 150 or other functional modules.

[0245] 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 technology (IR), etc. The wireless communication module 160 can be one or more devices that integrate at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via the antenna 2, modulates and filters the electromagnetic wave signal, and transmits the processed signal to the processor 110. The wireless communication module 160 can also receive signals to be transmitted from the processor 110, modulate and amplify them, and radiate them as electromagnetic waves via the antenna 2.

[0246] In some embodiments, the antenna 1 and the mobile communication module 150 of the display device 100 are coupled, and the antenna 2 and the wireless communication module 160 are coupled, so that the display device 100 can communicate with a network and other devices through wireless communication technology. The wireless communication technology can 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 can include global positioning system (GPS), global navigation satellite system (GLONASS), beidu navigation satellite system (BDS), quasi-zenith satellite system (QZSS), and / or satellite based augmentation systems (SBAS).

[0247] The display device 100 implements a display function through a GPU, a display screen 194, and an application processor, etc. The display screen 194 is used to display images, videos, etc.

[0248] The display device 100 can implement a photographing function through an ISP, a camera 193, a video codec, a GPU, a display screen 194, and an application processor, etc.

[0249] The digital signal processor is used to process digital signals, which can process digital image signals, but also can process other digital signals. For example, when the display device 100 selects a frequency point, the digital signal processor is used to perform Fourier transform on the frequency point energy, etc. The video codec is used to compress or decompress digital video. The NPU is a neural-network (NN) calculation processor, which processes input information quickly by drawing on the structure of biological neural networks, such as drawing on the transmission mode between human brain neurons, and can also constantly self-learn.

[0250] 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 realize the data storage function. For example, music, video, and other files are saved in the external memory card. The internal memory 121 can be used to store computer executable program code, which includes instructions.

[0251] The display device 100 can realize audio functions through the audio module 170, the speaker 170A, the receiver 170B, the microphone 170C, the earphone interface 170D, and the application processor, etc. For example, music playing, recording, etc.

[0252] The pressure sensor 180A is used to sense pressure signals and can convert the pressure signals into electrical signals. 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 a flip leather cover. The acceleration sensor 180E can detect the size of the acceleration of the display device 100 in each direction (usually three axes). When the display device 100 is stationary, the size and direction of gravity can be detected. It can also be used to identify the terminal posture, applied to landscape / portrait screen switching, pedometer, etc. The proximity light sensor 180G can include, for example, a light-emitting diode (LED) and a light detector, such as a photodiode. The light-emitting diode can be an infrared light-emitting diode. The display device 100 emits infrared light outwardly through the light-emitting diode. The ambient light sensor 180L is used to sense the ambient light brightness. The display device 100 can adaptively adjust the display screen 194 brightness according to the sensed ambient light brightness. The fingerprint sensor 180H is used to collect fingerprints. The temperature sensor 180J is used to detect temperature. The touch sensor 180K, also known as a "touch panel". The touch sensor 180K can be disposed on the display screen 194, and the touch sensor 180K and the display screen 194 form a touch screen, also known as 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.

[0253] In addition, the display device 100 further comprises an air pressure sensor 180C and a distance sensor 180F. The air pressure sensor 180C is configured to measure air pressure. In some embodiments, the display device 100 calculates altitude, assists positioning and navigation by using the air pressure value measured by the air pressure sensor 180C.

[0254] The distance sensor 180F is configured to measure distance. The display device 100 can measure distance by infrared or laser. In some embodiments, the display device 100 can use the distance sensor 180F to measure distance for fast focusing when shooting a scene.

[0255] For example, the software system of the display device 100 can adopt a layered architecture, an event-driven architecture, a micro-kernel architecture, a micro-service architecture, or a cloud architecture. The software structure of the display device 100 according to an embodiment of the present application is exemplarily described by taking a layered architecture of an Android system as an example. Figure 12 FIG. 1 is a software structure block diagram of the display device 100 according to an embodiment of the present application.

[0256] The layered architecture divides software into several layers, each of which has a clear role 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, an application layer, an application framework layer, an Android runtime, a system library, a kernel layer, a hardware abstraction layer (HAL), and a hardware layer.

[0257] The application layer can include a series of application packages. As shown in FIG. 2, the application packages can include camera, calendar, map, WLAN, music, short message, gallery, call, navigation, Bluetooth, video, and the like. Figure 12

[0258] The application framework layer provides application programming interfaces (APIs) and programming frameworks for the applications of the application layer. The application framework layer includes some pre-defined functions. As shown in FIG. 3, the application framework layer can include a window manager, a content provider, a phone manager, a resource manager, a notification manager, a view system, and the like. Figure 12

[0259] The window manager is configured to manage window programs. The window manager can obtain the size of the display screen, determine whether there is a status bar, lock the screen, and capture the screen, and the like.

[0260] ​​The content provider stores and retrieves data and makes the data accessible to applications. The data can include videos, images, audio, dialed and received calls, browsing history and bookmarks, phonebook, etc.

[0261] The view system includes visual controls, such as controls that display text, controls that display pictures, etc. The view system can be used to build an application. A display interface can be composed of one or more views. For example, a display interface that includes a short message notification icon can include a view that displays text and a view that displays a picture.

[0262] The telephony manager is used to provide communication functions of the display device 100. For example, management of call status (including call connection, call hang-up, etc.).

[0263] The resource manager provides various resources for applications, such as localized strings, icons, pictures, layout files, video files, etc.

[0264] The notification manager enables applications to display notification information in the status bar, which can be used to convey messages of the notification type, which can automatically disappear 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 top status bar of the system in the form of a chart or a scrolling text, such as a notification of an application 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 prompted in the status bar, a prompt sound is emitted, the terminal vibrates, the indicator light flashes, etc.

[0265] The Android Runtime includes a core library and a virtual machine. The Android Runtime is responsible for scheduling and managing the Android system.

[0266] The core library includes two parts: one part is the function function that the java language needs to call, and the other part is the core library of Android.

[0267] 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 into binary files. The virtual machine is used to perform functions such as management of the lifecycle of obstacles, stack management, thread management, management of security and exceptions, and garbage collection.

[0268] The system library can include multiple functional modules. For example: surface manager (surface manager), media library (Media Libraries), three-dimensional graphics processing library (for example: OpenGL ES), 2D graphics engine (for example: SGL), etc.

[0269] The surface manager is used to manage the display subsystem and provides 2D and 3D layer fusion for multiple applications.

[0270] The media library supports playback and recording of multiple common audio, video formats, and static image files. The media library can support multiple audio and video encoding formats, such as: MPEG4, H.264, MP3, AAC, AMR, JPG, PNG, and the like.

[0271] The three-dimensional graphics processing library is used to implement three-dimensional graphics drawing, image rendering, synthesis, and layer processing.

[0272] The 2D graphics engine is a drawing engine for 2D drawing.

[0273] The kernel layer is a layer between hardware and software. The kernel layer at least includes a display driver, a camera sensor driver, an audio driver, and a sensor driver.

[0274] Based on the same technical concept, the embodiments of the present application further provide a display device, comprising one or more processors; one or more memories; the one or more memories store one or more computer programs, the one or more computer programs comprise instructions, when the instructions are executed by the one or more processors, the computer or processor executes one or more steps in any one of the above methods.

[0275] Based on the same technical concept, the embodiments of the present application further provide a computer readable storage medium, the computer readable storage medium stores computer executable program instructions, when the computer executable program instructions are run on a computer, the computer or processor executes one or more steps in any one of the above methods.

[0276] Based on the same technical concept, the embodiments of the present application further provide a computer program product comprising instructions, the computer program product comprises computer program code, when the computer program code is run on a computer, the computer or processor executes one or more steps in any one of the above methods.

[0277] In the above embodiments, all or part of the methods can be implemented by software, hardware, firmware, or any combination thereof. When implemented by software, all or part of the methods can be implemented 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, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in or transmitted by a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center through a wired (such as coaxial cable, optical fiber, digital subscriber line) or wireless (such as infrared, wireless, microwave, etc.) manner. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes one or more available media sets. The available media can be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid state disk (SSD)), etc.

[0278] Those of ordinary skill in the art understand that all or part of the processes in the above embodiments can be implemented by a computer program that instructs relevant hardware, which can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the above embodiments.

[0279] The above is only a specific implementation of the embodiments of the present application, but the protection scope of the embodiments of the present application is not limited to this. Any changes or replacements within the technical scope disclosed in the embodiments of the present application should be covered in the protection scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application should be subject to the protection scope of the claims.

Claims

1. A method of high frequency PWM dimming, characterized by, The application is applied to a display device, comprising: Setting a target refresh rate as a base frequency, and setting a pulse number of an EM signal corresponding to the base frequency for brightness control as a reference pulse number; In a scanning area of a first refresh rate frame period, setting the pulse number of the EM signal corresponding to the scanning area as the reference pulse number, wherein a time length of the scanning area is the same as that of a base frequency frame period; In a first porch area corresponding to a second refresh rate, setting a first pulse number of the EM signal corresponding to the first porch area according to a target PWM frequency, a PWM frequency corresponding to the scanning area, and the second refresh rate, wherein the second refresh rate is a refresh rate that cannot be evenly divided by the first refresh rate, and the first pulse number of the EM signal is an integer; According to the target PWM frequency, the reference pulse number, and the first pulse number of the EM signal, reversely obtaining an actual refresh rate corresponding to a second refresh rate gear; In the second refresh rate gear, refreshing a screen of the display device according to the actual refresh rate; and According to the reference pulse number corresponding to the scanning area of the second refresh rate, and the first pulse number of the EM signal corresponding to the first porch area, lighting or extinguishing the screen of the display device.

2. The method of claim 1, wherein, The setting of the first pulse number of the EM signal 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 comprises: Obtaining a first result after the second refresh rate is divided by the target PWM frequency, wherein the first result is a non-integer; According to the first result, obtaining a first integer closest to the first result; According to the first integer, setting the first pulse number of the EM signal corresponding to the first porch area.

3. The method of claim 2, wherein, 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.

4. The method of claim 1, wherein, The setting of the first pulse number of the EM signal 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 comprises: Obtaining a first result after the second refresh rate is divided by the target PWM frequency, wherein the first result is a non-integer; According to the first result, obtaining a second integer second closest to the first result; According to the second integer, setting the first pulse number of the EM signal corresponding to the first porch area.

5. The method of claim 4, wherein, 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.

6. The method according to any one of claims 1-5, characterized in that, The reversely obtaining of the actual refresh rate corresponding to the second refresh rate gear according to the target PWM frequency, the reference pulse number, and the first pulse number of the EM signal specifically comprises: Summing the reference pulse number and the first pulse number of the EM signal to obtain a second result; obtaining a third result by dividing the second result by the target PWM frequency, the third result being an actual refresh rate corresponding to the second refresh rate level.

7. The method according to any one of claims 1-5, characterized in that, The actual refresh rate corresponding to the second refresh rate level is obtained in a Long-V mode, and the method further comprises: In the Long-H mode, according to the actual refresh rate, adjusting the time length of scanning each row of pixels in the image during refreshing, and obtaining an adjusted first row scanning time length, wherein the first row scanning time length makes the refresh rate corresponding to the refreshing adjusted to the second refresh rate.

8. The method according to any one of claims 1-5, characterized in that, The method further comprises: In a second porch area corresponding to a third refresh rate, copying the reference pulse number one or more times for the EM signal, wherein the third refresh rate is a refresh rate in the first refresh rate that can divide the base frequency; refreshing the screen of the display device according to the third refresh rate under the third refresh rate; and turning on or 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 copied reference pulse number corresponding to the second porch area.

9. The method according to any one of claims 1-5, characterized in that, The refreshing the screen of the display device according to the actual refresh rate under the second refresh rate level specifically comprises: Under the second refresh rate level, only performing the operation of refreshing the screen of the display device in the scanning area.

10. A display device, characterized by comprising: including: 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 comprise instructions that, when executed by the one or more processors, cause the display device to perform the method of 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, and the computer executable program instructions, when executed on a computer, cause the computer to perform the method of any one of claims 1 to 9.

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