CN116129820A - Backlight plate driving method and display screen - Google Patents
Backlight plate driving method and display screen Download PDFInfo
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- CN116129820A CN116129820A CN202310104554.5A CN202310104554A CN116129820A CN 116129820 A CN116129820 A CN 116129820A CN 202310104554 A CN202310104554 A CN 202310104554A CN 116129820 A CN116129820 A CN 116129820A
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
- G09G3/3413—Details of control of colour illumination sources
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/32—Pulse-control circuits
- H05B45/325—Pulse-width modulation [PWM]
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Abstract
The embodiment of the application provides a backlight driving method and a display screen, wherein when the ratio of the refresh rate of the backlight to the refresh rate of a panel is a first value, the first value is the sum of a second value and a preset positive integer, and the second value is the integer multiple of a target duty ratio, bright and dark water waves between adjacent image frames are complementary, the brightness of an image seen by human eyes is more uniform based on the principle of vision distance residual of the human eyes, and the condition of the water waves can be improved; in addition, the disordered PWM signals of the adjacent frames are different, so that the areas of the water ripple caused by the PWM signals are also different in the continuous adjacent frames, the display brightness difference is counteracted based on the principle of vision distance residual of human eyes, the brightness of the image seen by the human eyes is more uniform, and the condition of the water ripple can be improved.
Description
Technical Field
The application relates to the technical field of display, in particular to a backlight plate driving method and a display screen.
Background
The BLU (backlight Unit) is a provider of Light sources for the lcd, and the backlight determines the external visual sense of the lcd. The existing BLU adopts PWM (Pulse Width Modulation ) dimming mode to adjust the BLU brightness.
However, factors such as PWM dimming and sensitivity of OC (Open Cell, liquid crystal panel of unassembled BLU) to light may cause regular moving bright and dark bands at the visible fixed position on OC, i.e. cause Waterfall (water ripple) bad, thereby affecting display quality.
Disclosure of Invention
An objective of the embodiments of the present application is to provide a backlight driving method and a display screen, so as to improve the situation of Waterfall in the prior art. The specific technical scheme is as follows:
in a first aspect, embodiments of the present application provide a backlight driving method, including:
acquiring a panel refresh rate of a panel and acquiring a target duty cycle of a modulation signal of a backlight plate;
determining a backlight refresh rate of the backlight plate based on the panel refresh rate and the target duty cycle, wherein the ratio of the backlight plate refresh rate to the panel refresh rate is a first value, the first value is a sum of a second value and a preset positive integer, and the second value is an integer multiple of the target duty cycle;
generating an out-of-order pulse width modulation signal according to the backlight plate refresh rate and the target duty ratio, wherein the refresh frame rate of the out-of-order pulse width modulation signal is the backlight plate refresh rate, the duty ratio of each frame of pulse width modulation signal in the out-of-order pulse width modulation signal is the target duty ratio, and the out-of-order pulse width modulation signals of adjacent frames are different;
and driving the backlight plate to refresh by using the disordered pulse width modulation signal.
In one possible implementation manner, the obtaining the target duty ratio of the modulation signal of the backlight plate includes:
acquiring current ambient brightness;
and determining the duty ratio corresponding to the current ambient brightness according to the preset corresponding relation between the ambient brightness and the duty ratio, and obtaining the target duty ratio of the modulation signal of the backlight plate.
In one possible implementation, the determining the backlight refresh rate of the backlight based on the panel refresh rate and the target duty cycle includes:
the backlight refresh rate of the backlight is determined using the following formula:
wherein f BLU F for the backlight refresh rate OC For the panel refresh rate in question,
and for the target duty ratio, m and n are positive integers.
In one possible implementation, the generating the out-of-order pwm signal according to the backlight refresh rate and the target duty cycle includes:
and generating an out-of-order pulse width modulation signal meeting a preset rule according to the refresh rate of the backlight plate and the target duty ratio.
In one possible implementation, the generating the out-of-order pwm signal according to the backlight refresh rate and the target duty cycle includes:
and randomly generating an out-of-order pulse width modulation signal according to the refresh rate of the backlight plate and the target duty ratio.
In a second aspect, embodiments of the present application provide a backlight driving method, including:
acquiring a panel refresh rate of a panel and acquiring a target duty cycle of a modulation signal of a backlight plate;
determining a backlight refresh rate of the backlight plate based on the panel refresh rate and the target duty cycle, wherein the ratio of the backlight plate refresh rate to the panel refresh rate is a first value, the first value is a sum of a second value and a preset positive integer, and the second value is an integer multiple of the target duty cycle;
generating a target pulse width modulation signal according to the backlight plate refresh rate and the target duty ratio, wherein the refresh frame rate of the target pulse width modulation signal is the backlight plate refresh rate, and the duty ratio of each frame of pulse width modulation signal in the target pulse width modulation signal is the target duty ratio;
and driving the backlight plate to refresh by using the target pulse width modulation signal.
In one possible implementation manner, the obtaining the target duty ratio of the modulation signal of the backlight plate includes:
acquiring current ambient brightness;
and determining the duty ratio corresponding to the current ambient brightness according to the preset corresponding relation between the ambient brightness and the duty ratio, and obtaining the target duty ratio of the modulation signal of the backlight plate.
In one possible implementation, the determining the backlight refresh rate of the backlight based on the panel refresh rate and the target duty cycle includes:
the backlight refresh rate of the backlight is determined using the following formula:
wherein f BLU F for the backlight refresh rate OC For the panel refresh rate in question,
and for the target duty ratio, m and n are positive integers.
In a third aspect, embodiments of the present application provide a backlight driving method, including:
acquiring a target duty ratio of a modulation signal of a backlight plate and a backlight plate refresh rate of the backlight plate;
generating an out-of-order pulse width modulation signal according to the backlight plate refresh rate and the target duty ratio, wherein the refresh frame rate of the out-of-order pulse width modulation signal is the backlight plate refresh rate, the duty ratio of each frame of pulse width modulation signal in the out-of-order pulse width modulation signal is the target duty ratio, and the out-of-order pulse width modulation signals of adjacent frames are different;
and driving the backlight plate to refresh by using the disordered pulse width modulation signal.
In one possible implementation, the generating the out-of-order pwm signal according to the backlight refresh rate and the target duty cycle includes:
and generating an out-of-order pulse width modulation signal meeting a preset rule according to the refresh rate of the backlight plate and the target duty ratio.
In one possible implementation, the generating the out-of-order pwm signal according to the backlight refresh rate and the target duty cycle includes:
and randomly generating an out-of-order pulse width modulation signal according to the refresh rate of the backlight plate and the target duty ratio.
In a fourth aspect, an embodiment of the present application provides a display screen, including a backlight plate, a panel, and a control chip, where the control chip is configured to implement any one of the backlight plate driving methods in the present application when running.
The beneficial effects of the embodiment of the application are that:
according to the backlight driving method and the display screen, when the ratio of the refresh rate of the backlight to the refresh rate of the panel is the first value, the first value is the sum of the second value and the preset positive integer, and the second value is the integer multiple of the target duty ratio, the bright and dark water waves between adjacent image frames are complementary, the brightness of an image seen by human eyes is more uniform based on the principle of vision distance residual of the human eyes, and the condition of the water waves can be improved; in addition, the disordered PWM signals of the adjacent frames are different, so that the areas of the water ripple caused by the PWM signals are also different in the continuous adjacent frames, the display brightness difference is counteracted based on the principle of vision distance residual of human eyes, the brightness of the image seen by the human eyes is more uniform, and the condition of the water ripple can be improved.
Of course, not all of the above-described advantages need be achieved simultaneously in practicing any one of the products or methods of the present application.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following description will briefly introduce the drawings that are required to be used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other embodiments may also be obtained according to these drawings to those skilled in the art.
FIG. 1 is a schematic diagram of a Waterfall adverse phenomenon in the related art;
FIG. 2 is a schematic diagram of the positive and negative voltage signals and some measured values of three different BLUs according to the related art;
FIG. 3 is a schematic diagram of a display frame generated by the influence of a BLU PWM dimming method on an OC of a frame in the related art;
FIG. 4 is a first schematic diagram of a display frame generated by the influence of a BLU PWM dimming method on the OC of consecutive multi-frame frames in the related art;
fig. 5 is a schematic flow chart of a first method for driving a backlight panel according to an embodiment of the present application;
FIG. 6a is a schematic diagram of a first flow chart of an adjacent frame visual superposition effect according to an embodiment of the present application;
FIG. 6b is a first schematic diagram of a visual superposition effect of adjacent frames in the related art;
FIG. 6c is a second flowchart of an adjacent frame visual overlay effect according to an embodiment of the present application;
FIG. 7a is a schematic diagram of a hardware implementation of a backlight driving method in the related art;
FIG. 7b is a first schematic diagram of a hardware implementation of a backlight driving method according to an embodiment of the present application;
fig. 8 is a schematic diagram of a second flow chart of a backlight driving method according to an embodiment of the present application;
FIG. 9a is a second schematic diagram of the visual superposition effect of adjacent frames in the related art;
fig. 9b is a third flowchart of an adjacent frame visual superposition effect according to an embodiment of the present application;
fig. 9c is a fourth flowchart of an adjacent frame visual superposition effect according to an embodiment of the present application;
FIG. 10a is a second schematic diagram of a hardware implementation of a backlight driving method according to an embodiment of the present application;
FIG. 10b is a third schematic diagram of a hardware implementation of a backlight driving method according to an embodiment of the present application;
FIG. 11 is a third flow chart of a driving method of a backlight panel according to an embodiment of the present disclosure;
fig. 12 is a fourth schematic diagram of a hardware implementation of the backlight driving method according to the embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. Based on the embodiments herein, a person of ordinary skill in the art would be able to obtain all other embodiments based on the disclosure herein, which are within the scope of the disclosure herein.
In the related art, the Waterfall defect refers to a bright and dark band that is generated by regular movement of a visible fixed position on the OC, and the generation of the bright and dark band is mainly related to the sensitivity of the OC to light and the PWM dimming mode of the BLU, as shown in fig. 1, and is a Waterfall defect phenomenon of the whole display, which is specifically expressed as follows: five sets of transverse light and dark bands.
The PWM dimming method is a dimming method in which the frequency of a modulation signal is not changed and the pulse width (duty ratio) is changed. Using this dimming scheme, the BLU is turned on and off (or changed in brightness) at a certain frequency and duty ratio. The modulating signal is loaded on the positive and negative electrode model of the BLU, and the differential pressure signal (VLED+ -VLED-) which is embodied as the positive and negative electrode signal of the BLU has certain frequency and duty ratio: when the positive and negative signal pressure difference is large, the BLU presents high brightness; when the voltage difference of the positive and negative signals is smaller, the BLU presents low brightness; and changing the duty ratio of the BLU positive and negative voltage difference signal to realize the brightness value between the high brightness and the low brightness. As shown in fig. 2, fig. 2 shows the positive and negative voltage signals of three different BLU and some measured values thereof. As can be seen, the three BLU are all fixed frequency (fixed f VLED ) And a dimming mode in which the duty ratio is changed, i.e., a PWM dimming mode, in which_h represents a high level and_l represents a low level.
The sensitivity of OC to light is mainly reflected in the fact that Active Tail on an in-plane array substrate is susceptible to illumination: when the BLU brightness is higher, the Active Tail conductivity of the corresponding area is better, so that RC Delay (signal Delay caused by the charging and discharging process of the resistance control capacitor) is increased, the charging rate of the area is reduced, the transmittance of the area is reduced, and the display is dark; conversely, when the BLU brightness is low, the display of the corresponding region is bright.
As shown in fig. 3, the intra-frame OC is indicated by the influence of the BLU PWM dimming method. In the figure, the picture is G80 Pattern, the duty ratio of BLU PWM signal (i.e. the ratio of the high level time of the backlight positive-negative voltage difference VLED+ -VLED-signal to the signal period) is 50%, the BLU refresh rate (f BLU I.e., the frequency of change of the backlight positive-negative voltage difference signal vled+ -VLED-in the figure) and the OC refresh rate (f) OC ) The ratio is 2, namely: f (f) BLU /f OC =2 (e.g. OC refresh rate is 60Hz, blu refresh rate is 120 Hz). The BLU signal changes twice during one frame time of the OC. In the period of large difference between positive and negative voltages of the BLU, the Gate in the OC plane is opened row by row, and about 1/4 area is scanned, and the brightness of the corresponding area opened by the Gate is dark due to the photosensitivity of the Active Tail (shown as G70 in practice); during the period of small difference between positive and negative voltages of the BLU, the OC in-plane re-scans about 1/4 area, which is also affected by the photosensitivity of the Active Tail, the area exhibits a bright (as shown in practice as G90). Thus, the frame image displays two groups of bright and dark bands which are dark, bright, dark and bright.
Fig. 4 is a schematic diagram of a display screen in which OC of consecutive multi-frame pictures is affected by BLU PWM dimming. Wherein a BLU PWM signal duty cycle of 50% is illustrated. In fig. 4, the ratio of BLU refresh rate to OC refresh rate is also 2, namely: f (f) BLU /f OC =2. In this case, the pictures of the continuous frames are displayed as two groups of bright and dark bands of dark-bright-dark-bright, so that the macroscopic picture is the picture of two groups of bright and dark bands at fixed positions.
In order to improve the water ripple condition of the display screen, the embodiment of the application provides a backlight driving method and the display screen, and the method and the device are specifically described below.
Referring to fig. 5, fig. 5 is a first schematic diagram of a backlight driving method according to an embodiment of the present application, including:
s110, acquiring a panel refresh rate of the panel and acquiring a target duty ratio of a modulation signal of the backlight plate.
S120, determining a backlight plate refresh rate of the backlight plate based on the panel refresh rate and the target duty ratio, wherein the ratio of the backlight plate refresh rate to the panel refresh rate is a first value, the first value is the sum of a second value and a preset positive integer, and the second value is an integer multiple of the target duty ratio.
S130, generating a target pulse width modulation signal according to the refresh rate of the backlight plate and the target duty ratio, wherein the refresh frame rate of the target pulse width modulation signal is the refresh rate of the backlight plate, and the duty ratio of each frame of pulse width modulation signal in the target pulse width modulation signal is the target duty ratio.
And S140, driving the backlight plate to refresh by using the target pulse width modulation signal.
The panel in the embodiment of the present application and the backlight plate to be driven belong to the same display screen, and specifically, the panel may be an OC in the display screen. The panel can be a panel with a higher refresh rate, such as a high refresh rate of 120Hz, 144Hz, 240Hz, 288Hz, etc., or a panel with a variable refresh rate, such as a product with VRR (Variable Refresh Rate ) function. The backlight board may be a Mini-LED (Mini-Light Emitting Diode, mini Light Emitting Diode), LCD (Liquid Crystal Display ), OLED (Organic Light-Emitting Diode) product with PWM dimming and variable BLU brightness along with ambient Light.
The panel refresh rate of OC is obtained first, and the panel refresh rate may be any value, for example, the panel refresh rate is 60Hz, etc. The duty ratio of the modulated signal of the backlight Board (BLC) is the target duty ratio, and may be 50%,40%, etc. The target duty ratio of the modulated signal of the BLC may be a fixed value for a BLU whose brightness does not change with ambient light, i.e., the target duty ratio of the modulated signal of the BLC may be directly determined based on a preset duty ratio, and the target duty ratio of the modulated signal of the BLC may be determined based on the ambient brightness and a preset correspondence between the ambient brightness and the duty ratio for a BLU whose brightness changes with ambient light. For clarity of solution and clarity of layout, a detailed description is provided below in connection with another embodiment.
After the panel refresh rate of the panel and the target duty cycle of the modulation signal of the backlight are obtained, the backlight refresh rate of the backlight can be determined based on the obtained panel refresh rate and the target duty cycle, when the BLU PWM signal duty cycle is fixed, the backlight refresh rate of the backlight is determined at a specific f BLU /f OC In this case, waterfall failure can be ameliorated; wherein, at the backlight refresh rate: the ratio of the refresh rate of the backlight plate to the refresh rate of the panel is a first value, and the first value is the sum of a second value and a preset positive integer, and the second value is an integer multiple of the target duty cycle, so that Waterfall failure can be improved. For example, the panel refresh rate is 60Hz and the target duty cycle is 50%, then the backlight refresh rate may be determined to be 150Hz, 210Hz, 270Hz.
For example, as shown in FIG. 6a, the ratio of BLU refresh rate to OC refresh rate is 2.5, i.e., f BLU /f OC =2.5 (e.g. OC refresh rate of 60Hz, blu refresh rate of 150 Hz). In this case, the pictures of two consecutive frames are displayed as "dark-bright-dark" and "bright-dark-bright", based on the principle of the eye's visual distance residual, at which time the bright and dark of two consecutive frames cancel each other in the macro-eye's visual effect, and the picture defect is improved.
After the refresh rate of the backlight plate is obtained, a target pulse width modulation signal can be generated according to the refresh rate of the backlight plate and the target duty ratio, wherein the refresh frame rate of the target pulse width modulation signal is the refresh rate of the backlight plate, the duty ratio of each frame of pulse width modulation signal in the target pulse width modulation signal is the target duty ratio, the backlight plate is driven to refresh by using the target pulse width modulation signal, and based on the view-distance residual principle of human eyes, continuous frames on the macro-human visual effect can cancel each other, and the picture defect is improved.
In the embodiment of the application, when the ratio of the refresh rate of the backlight plate to the refresh rate of the panel is a first value, and the first value is the sum of a second value and a preset positive integer and the second value is the integer multiple of the target duty ratio, the bright and dark water ripples between adjacent image frames are complementary, and based on the principle of vision distance residual of human eyes, the brightness of an image seen by human eyes is more uniform, and the condition of water ripples can be improved.
In one possible implementation manner, the acquiring the target duty ratio of the modulation signal of the backlight plate includes:
step one, obtaining the current ambient brightness.
And step two, determining the duty ratio corresponding to the current ambient brightness according to the preset corresponding relation between the ambient brightness and the duty ratio, and obtaining the target duty ratio of the modulation signal of the backlight plate.
The brightness of the BLU may vary with the brightness of the ambient light, in one example, when the ambient brightness is high, in order to adapt to the ambient brightness, the BLU may be high brightness, i.e., the duty cycle of the PWM of the BLU is high; conversely, when the ambient brightness is low, the BLU may be low in brightness, i.e., the PWM duty cycle of the BLU is low, in order to protect the human eye. Therefore, when the duty ratio of the BLU changes with the ambient brightness, the preset corresponding relation between the ambient brightness and the duty ratio can be obtained, so that when the target duty ratio of the modulation signal of the backlight plate needs to be obtained, the current ambient brightness can be obtained first, and the duty ratio corresponding to the current ambient brightness is determined according to the preset corresponding relation between the ambient brightness and the duty ratio, so as to obtain the target duty ratio of the modulation signal of the BLU. That is, for a BLU whose brightness may vary with the brightness of ambient light, the target duty ratio of the modulation signal of the BLU may be accurately acquired based on the ambient brightness.
The preset corresponding relation between the ambient brightness and the duty ratio can be stored in a preset storage medium in advance, so that after the current ambient brightness is obtained, the preset corresponding relation between the ambient brightness and the duty ratio can be directly obtained from a preset database based on the current ambient brightness, and further the duty ratio corresponding to the current ambient brightness can be determined, and the target duty ratio of the modulation signal of the BLU is obtained.
In one possible embodiment, the determining the backlight refresh rate of the backlight based on the panel refresh rate and the target duty ratio includes:
the backlight refresh rate of the backlight is determined using the following formula:
wherein f BLU F for the backlight refresh rate OC For the panel refresh rate described above,
and m and n are positive integers for the target duty ratio. b and a are mutually exclusive and m and a are mutually exclusive.
When the brightness of the BLU changes, i.e. the duty ratio of the modulation signal of the backlight plate changes, i.e. a and b change, f can be obtained by setting the appropriate values of m and n BLU And f OC Matching to ameliorate Waterfall failure.
Illustratively, in the case where the panel refresh rate is 60Hz and the target duty cycle is 50%, the backlight refresh rate is one of the following frequencies: 150Hz, 210Hz, 270Hz, 330Hz, 390Hz, 450Hz, 510Hz.
Illustratively, in the case where the panel refresh rate is 60Hz and the target duty cycle is 40%, the backlight refresh rate is one of the following frequencies: 252Hz, 264Hz, 276Hz, 288Hz, 312Hz, 324Hz, 336Hz, 348Hz.
When the duty ratio of the PWM signal is 40%, f BLU /f OC =10/5, there will be a bright dark band, see in particular fig. 6b; at this time, if the BLU refresh rate is adjusted, f can be changed BLU /f OC Is a value of (2). Specifically, the value can be reasonably adjusted according to the formula, such as setting f BLU /f OC When the PWM signal is 8/5, the occurrence of Waterfall adverse phenomena can be improved, wherein the PWM signal duty ratio is 40%, f BLU /f OC The result of 8/5 is shown in fig. 6c, and based on the principle of eye-distance residual, the continuous frames in macro-eye viewing effect cancel each other out, so that poor picture is improved.
In an example, as shown in fig. 7a and fig. 7b, fig. 7a is a conventional PWM dimming scheme, a PWM signal is provided by an SOC (System on Chip), and a PWM generation module is generally integrated inside the SOC; and then an LED Driver IC (backlight plate driving circuit) module loads PWM signals onto positive and negative voltage signals of the BLU and sends the PWM signals to the lamp beads on the BLU lamp panel or the lamp strip, so that the brightness of the BLU is controlled by PWM dimming.
In this embodiment, the PWM generation module is changed to a PWM-PFM (Pulse Frequency Modulation ) generation module, as shown in fig. 7b, and the PWM-PFM generation module may be integrated inside the SOC or may be an integrated circuit independent of the SOC. After the SOC obtains the backlight refresh rate by the above-mentioned backlight driving method, the frequency of the output PWM signal is dynamically set, and a PWM-PFM signal (corresponding to the target pulse width modulation signal) is output. And then the LED Driver IC module loads PWM-PFM signals to the anode and cathode signals of the BLU to control the brightness of the BLU. The PWM-PFM generating module shown in fig. 7b may also be separately split into two modules, that is, a PWM frequency setting module is added after the PWM generating module, and the principle of integration or splitting is the same, which is within the protection scope of the present application.
In order to improve the phenomenon of water ripple, the embodiment of the present application further provides a backlight driving method, referring to fig. 8, including:
s210, acquiring a target duty ratio of a modulation signal of a backlight plate and a backlight plate refresh rate of the backlight plate.
S220, generating an out-of-order pulse width modulation signal according to the backlight plate refresh rate and the target duty ratio, wherein the refresh frame rate of the out-of-order pulse width modulation signal is the backlight plate refresh rate, the duty ratio of each frame of pulse width modulation signal in the out-of-order pulse width modulation signal is the target duty ratio, and the out-of-order pulse width modulation signals of adjacent frames are different.
S230, driving the backlight plate to refresh by using the disordered pulse width modulation signal.
Based on the backlight refresh rate and the target duty cycle, an out-of-order Pulse Width Modulation (PWM) signal can be generated, wherein the refresh frame rate of the out-of-order PWM signal is the backlight refresh rate, the duty cycle of each frame of the pulse width modulation signal in the out-of-order PWM signal is the target duty cycle, but the out-of-order pulse width modulation signals of adjacent frames are different.
FIG. 9a shows a non-out-of-order PWM signal, the PWM signals of adjacent frames are identical, the BLU PWM duty cycle is 40%, f BLU /f OC After overlapping, adjacent image frames have obvious moire phenomenon. FIGS. 9b and 9c show out-of-order PWM signals with a BLU PWM duty cycle of 40%, f BLU /f OC The method is 10/5, but PWM signals of adjacent frames are different, the backlight plate is driven to refresh by using the disordered PWM signals, the positions of water waves between adjacent image frames are different, and based on the principle of eye-sight distance residual, continuous frames on the macro-sight effect are mutually counteracted, so that poor picture is improved.
In this application implementation, the disordered PWM signal of adjacent frame is different, consequently, in the continuous adjacent frame, the region of the ripple that the PWM signal caused also is different, based on the principle is remained to the stadia of people's eye, shows that the luminance difference can offset, and the luminance of the image that the people's eye sees is more even, can improve the condition of ripple.
The out-of-order PWM signals may be either regular or random. In one possible implementation, the generating the out-of-order pwm signal according to the backlight refresh rate and the target duty cycle includes: and generating an out-of-order pulse width modulation signal meeting a preset rule according to the refresh rate of the backlight plate and the target duty ratio.
The preset rule may be set by user according to the actual situation, for example, the time sequence of the PWM signal may be shifted axially forward or backward by a preset time length in the adjacent frame, for example, as shown in fig. 9b, and the time sequence of the PWM signal may be shifted backward by the preset time length in the time axis in the adjacent frame.
In one possible implementation, the generating the out-of-order pwm signal according to the backlight refresh rate and the target duty cycle includes: and randomly generating an out-of-order pulse width modulation signal according to the backlight plate refresh rate and the target duty ratio.
The out-of-order PWM signals are randomly generated, that is, the timing of the out-of-order PWM signals is randomly generated, but the duty ratio of each frame of PWM signals needs to be satisfied to be the target duty ratio, for example, as shown in fig. 9c, it can be seen that adjacent frames, the timing of the PWM signals is not obviously regular, but the duty ratios of the PWM signals in each frame are all satisfied to be the target duty ratio.
In an example, as shown in fig. 10a and fig. 10b, in an implementation manner of adding a PWM disorder module after a PWM generation module, the PWM disorder module outputs a disorder PWM signal to an LED Driver IC module, loads the disorder PWM signal onto a BLU positive and negative electrode signal to form a disorder BLU positive and negative electrode signal (corresponding to a disorder pulse width modulation signal), and then sends the disorder BLU positive and negative electrode signal to a BLU lamp panel or lamp bar to realize brightness control. Wherein, the PWM out-of-order module may be integrated in the SOC module. In one example, the disorder module may be further placed after the LED Driver IC module, for example, as shown in fig. 10b, after the positive and negative signals of the BLU loaded with the PWM signal pass through the positive and negative signals disorder module of the BLU, the positive and negative signals of the BLU (corresponding to the disorder pulse width modulation signal) are generated and sent to the BLU lamp panel or lamp strip, so as to realize brightness control of the BLU. When the implementation mode is used, the out-of-order module can be independently established, and can also be integrated with the inside of the LED Driver IC module.
The embodiment of the application also provides a backlight driving method, referring to fig. 11, the method includes:
s310, acquiring a panel refresh rate of a panel and acquiring a target duty cycle of a modulation signal of a backlight plate.
S320, determining a backlight plate refresh rate of the backlight plate based on the panel refresh rate and the target duty ratio, wherein the ratio of the backlight plate refresh rate to the panel refresh rate is a first value, the first value is the sum of a second value and a preset positive integer, and the second value is an integer multiple of the target duty ratio.
S330, generating an out-of-order pulse width modulation signal according to the backlight plate refresh rate and the target duty ratio, wherein the refresh frame rate of the out-of-order pulse width modulation signal is the backlight plate refresh rate, the duty ratio of each frame of pulse width modulation signal in the out-of-order pulse width modulation signal is the target duty ratio, and the out-of-order pulse width modulation signals of adjacent frames are different.
S340, driving the backlight plate to refresh by using the disordered pulse width modulation signal.
In the embodiment of the application, when the ratio of the refresh rate of the backlight plate to the refresh rate of the panel is a first value, the first value is the sum of a second value and a preset positive integer, and the second value is the integer multiple of the target duty ratio, the bright and dark water ripples between adjacent image frames are complementary, and based on the principle of vision distance residual of human eyes, the brightness of an image seen by human eyes is more uniform, and the condition of water ripples can be improved; in addition, the disordered PWM signals of the adjacent frames are different, so that the areas of the water ripple caused by the PWM signals are also different in the continuous adjacent frames, the display brightness difference is counteracted based on the principle of vision distance residual of human eyes, the brightness of the image seen by the human eyes is more uniform, and the condition of the water ripple can be improved.
In one possible implementation manner, the obtaining the target duty ratio of the modulation signal of the backlight plate includes: acquiring current ambient brightness; and determining the duty ratio corresponding to the current ambient brightness according to the preset corresponding relation between the ambient brightness and the duty ratio, and obtaining the target duty ratio of the modulation signal of the backlight plate.
In one possible implementation, the determining the backlight refresh rate of the backlight based on the panel refresh rate and the target duty cycle includes:
the backlight refresh rate of the backlight is determined using the following formula:
wherein f BLU For the backlight scrubberNew rate, f OC For the panel refresh rate in question,
and for the target duty ratio, m and n are positive integers.
In one possible implementation, the generating the out-of-order pwm signal according to the backlight refresh rate and the target duty cycle includes:
and generating an out-of-order pulse width modulation signal meeting a preset rule according to the refresh rate of the backlight plate and the target duty ratio.
In one possible implementation, the generating the out-of-order pwm signal according to the backlight refresh rate and the target duty cycle includes:
and randomly generating an out-of-order pulse width modulation signal according to the refresh rate of the backlight plate and the target duty ratio.
In the embodiment of the present application, the driving method of the backlight plate may be implemented by means of hardware and software, and in one example, as shown in fig. 12, the PWM generation module in the related art is changed to a PWM-PFM generation module, and the PWM-PFM generation module may be integrated inside the SOC or may be an integrated circuit independent of the SOC. And a PWM disorder module is added after the PWM-PFM generation module, outputs a disorder PWM-PFM signal to the LED Driver IC module, and loads the disorder PWM-PFM signal to the positive and negative signals of the BLU to form a disorder BLU positive and negative signal (corresponding to a disorder pulse width modulation signal), and then the disorder BLU positive and negative signal is sent to a BLU lamp panel or lamp strip to realize brightness control. In other embodiments, a BLU positive and negative signal disorder module may be added after the LED Driver IC module, which are all within the protection scope of the present application.
The embodiment of the application provides a display screen, which comprises a backlight plate, a panel and a control chip, wherein the control chip is used for realizing any backlight plate driving method in the application when in operation.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
In this specification, each embodiment is described in a related manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. In particular, for the display screen, since it is substantially similar to the method embodiment, the description is relatively simple, and reference is made to the partial description of the method embodiment for relevant points.
The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the scope of the present application. Any modifications, equivalent substitutions, improvements, etc. that are within the spirit and principles of the present application are intended to be included within the scope of the present application.
Claims (12)
1. A backlight driving method, the method comprising:
acquiring a panel refresh rate of a panel and acquiring a target duty cycle of a modulation signal of a backlight plate;
determining a backlight refresh rate of the backlight plate based on the panel refresh rate and the target duty cycle, wherein the ratio of the backlight plate refresh rate to the panel refresh rate is a first value, the first value is a sum of a second value and a preset positive integer, and the second value is an integer multiple of the target duty cycle;
generating an out-of-order pulse width modulation signal according to the backlight plate refresh rate and the target duty ratio, wherein the refresh frame rate of the out-of-order pulse width modulation signal is the backlight plate refresh rate, the duty ratio of each frame of pulse width modulation signal in the out-of-order pulse width modulation signal is the target duty ratio, and the out-of-order pulse width modulation signals of adjacent frames are different;
and driving the backlight plate to refresh by using the disordered pulse width modulation signal.
2. The method of claim 1, wherein the obtaining a target duty cycle of the modulation signal of the backlight plate comprises:
acquiring current ambient brightness;
and determining the duty ratio corresponding to the current ambient brightness according to the preset corresponding relation between the ambient brightness and the duty ratio, and obtaining the target duty ratio of the modulation signal of the backlight plate.
3. The method of claim 1, wherein the determining a backlight refresh rate of the backlight based on the panel refresh rate and the target duty cycle comprises:
the backlight refresh rate of the backlight is determined using the following formula:
wherein f BLU F for the backlight refresh rate OC For the panel refresh rate in question,
and for the target duty ratio, m and n are positive integers.
4. The method of claim 1, wherein generating the out-of-order pulse width modulated signal according to the backlight refresh rate and the target duty cycle comprises:
and generating an out-of-order pulse width modulation signal meeting a preset rule according to the refresh rate of the backlight plate and the target duty ratio.
5. The method of claim 1, wherein generating the out-of-order pulse width modulated signal according to the backlight refresh rate and the target duty cycle comprises:
and randomly generating an out-of-order pulse width modulation signal according to the refresh rate of the backlight plate and the target duty ratio.
6. A backlight driving method, the method comprising:
acquiring a panel refresh rate of a panel and acquiring a target duty cycle of a modulation signal of a backlight plate;
determining a backlight refresh rate of the backlight plate based on the panel refresh rate and the target duty cycle, wherein the ratio of the backlight plate refresh rate to the panel refresh rate is a first value, the first value is a sum of a second value and a preset positive integer, and the second value is an integer multiple of the target duty cycle;
generating a target pulse width modulation signal according to the backlight plate refresh rate and the target duty ratio, wherein the refresh frame rate of the target pulse width modulation signal is the backlight plate refresh rate, and the duty ratio of each frame of pulse width modulation signal in the target pulse width modulation signal is the target duty ratio;
and driving the backlight plate to refresh by using the target pulse width modulation signal.
7. The method of claim 6, wherein the obtaining a target duty cycle of the modulation signal of the backlight plate comprises:
acquiring current ambient brightness;
and determining the duty ratio corresponding to the current ambient brightness according to the preset corresponding relation between the ambient brightness and the duty ratio, and obtaining the target duty ratio of the modulation signal of the backlight plate.
8. The method of claim 6, wherein the determining a backlight refresh rate of the backlight based on the panel refresh rate and the target duty cycle comprises:
the backlight refresh rate of the backlight is determined using the following formula:
wherein f BLU F for the backlight refresh rate OC For the panel refresh rate in question,
and for the target duty ratio, m and n are positive integers.
9. A backlight driving method, the method comprising:
acquiring a target duty ratio of a modulation signal of a backlight plate and a backlight plate refresh rate of the backlight plate;
generating an out-of-order pulse width modulation signal according to the backlight plate refresh rate and the target duty ratio, wherein the refresh frame rate of the out-of-order pulse width modulation signal is the backlight plate refresh rate, the duty ratio of each frame of pulse width modulation signal in the out-of-order pulse width modulation signal is the target duty ratio, and the out-of-order pulse width modulation signals of adjacent frames are different;
and driving the backlight plate to refresh by using the disordered pulse width modulation signal.
10. The method of claim 9, wherein generating the out-of-order pwm signal according to the backlight refresh rate and the target duty cycle comprises:
and generating an out-of-order pulse width modulation signal meeting a preset rule according to the refresh rate of the backlight plate and the target duty ratio.
11. The method of claim 9, wherein generating the out-of-order pwm signal according to the backlight refresh rate and the target duty cycle comprises:
and randomly generating an out-of-order pulse width modulation signal according to the refresh rate of the backlight plate and the target duty ratio.
12. A display screen comprising a backlight, a panel and a control chip for implementing the method of any of the preceding claims 1-11 when in operation.
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