CN116229894A - Display device and driving method thereof - Google Patents

Display device and driving method thereof Download PDF

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Publication number
CN116229894A
CN116229894A CN202310213082.7A CN202310213082A CN116229894A CN 116229894 A CN116229894 A CN 116229894A CN 202310213082 A CN202310213082 A CN 202310213082A CN 116229894 A CN116229894 A CN 116229894A
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China
Prior art keywords
gray
display
scale
slope
brightness
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CN202310213082.7A
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Chinese (zh)
Inventor
高翔宇
王广
余志华
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Wuhan Tianma Microelectronics Co Ltd
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Wuhan Tianma Microelectronics Co Ltd
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Priority to CN202310213082.7A priority Critical patent/CN116229894A/en
Publication of CN116229894A publication Critical patent/CN116229894A/en
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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
    • G09G3/22—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 using controlled light sources
    • G09G3/30—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 using controlled light sources using electroluminescent panels
    • G09G3/32—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • 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
    • G09G3/22—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 using controlled light sources
    • G09G3/30—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 using controlled light sources using electroluminescent panels
    • G09G3/32—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208—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 using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • G09G3/3275—Details of drivers for data electrodes
    • G09G3/3291—Details of drivers for data electrodes in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0264—Details of driving circuits
    • G09G2310/027—Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0233—Improving the luminance or brightness uniformity across the screen
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0271—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)

Abstract

The invention discloses a display device and a driving method thereof, wherein the display device comprises: the display panel comprises a plurality of sub-pixels, the first data storage unit is used for storing gray-scale compensation data, the correction coefficient acquisition unit obtains correction coefficients according to a first slope and a second slope, the first slope is a curve slope of gray scale and voltage under current display brightness, the second slope is a curve slope of gray scale and voltage under display brightness, and the compensation unit obtains actual gray-scale compensation values according to the gray-scale compensation data and the correction coefficients to perform gray-scale compensation on a display picture of the display panel. The invention can enhance the optical compensation capability in the DC dimming mode and solve the poor visual effect caused by uneven display in the DC dimming mode.

Description

Display device and driving method thereof
Technical Field
The present invention relates to the field of display technologies, and more particularly, to a display device and a driving method thereof.
Background
With the development of electronic technology, the manufacturing of display panels has also tended to mature, and display panels provided in the prior art include liquid crystal display panels, organic light emitting display panels, plasma display panels, and the like. Organic light emitting diodes are increasingly used as a current-type light emitting device in high performance display, and an OLED display panel has excellent characteristics of self-luminescence, wide viewing angle, fast response speed, high contrast, wide color gamut, low energy consumption, thin panel, rich color, flexible display realization, wide operating temperature range and the like, so that the OLED display panel is known as a next-generation 'star' flat panel display technology. The OLED display panel comprises an anode, a cathode, a hole transmission layer, an organic light-emitting layer and an electron transmission layer, wherein the hole transmission layer, the organic light-emitting layer and the electron transmission layer are arranged between the anode and the cathode, the anode provides hole injection, the cathode provides electron injection, the holes and electrons injected by the cathode and the anode are combined in the organic light-emitting layer under the driving of external voltage, electron hole pairs (namely excitons) at a binding energy level are formed, and the excitons radiate and are de-excited to emit photons to generate visible light.
Mura is a phenomenon that brightness in a display panel is uneven, various marks are caused, and the cause of the Mura is that, due to the fact that sub-pixel materials in the display panel are made, when the same voltage is provided for the sub-pixels, different currents are generated, the brightness of different sub-pixels is different, the larger the difference is, the more serious the Mura is, the smaller the difference is, and the smaller the Mura is.
At present, the display panel is dimmed in two modes, namely a PWM mode and a DC mode, wherein the principle of the DC mode is that the display brightness is controlled by adjusting the voltage or the current of the display panel and changing the power, and the PWM mode alternately blinks on a certain frequency by controlling the display panel under the condition of not changing the power, so that the effect of continuous display is achieved by utilizing the visual residual effect of human eyes. In short, in the DC mode, the display panel is in a lit state for one frame time, and in the PWM mode, the display panel is continuously alternately lit, turned off, and turned on for one frame time, and the screen brightness is changed by changing the alternating time.
In PWM mode, mura may be significantly improved, but in DC mode, mura compensation is poor and demux compensation is poor at low brightness.
Accordingly, there is a need for a display device and a driving method thereof capable of enhancing the optical compensation capability in the DC dimming mode and solving the poor visual effect caused by the uneven display in the DC dimming mode.
Disclosure of Invention
In view of the above, the present invention provides a display device and a driving method thereof for enhancing the optical compensation capability in the DC dimming mode and solving the poor visual effect caused by the uneven display in the DC dimming mode.
In one aspect, the present invention provides a display device including:
a display panel including a plurality of sub-pixels;
a first data storage unit for storing gray-scale compensation data;
the correction coefficient acquisition unit is used for obtaining a correction coefficient according to a first slope and a second slope, wherein the first slope is a curve slope of gray scale and voltage under current display brightness, and the second slope is a curve slope of gray scale and voltage under basic display brightness;
and the compensation unit is used for obtaining an actual gray-scale compensation value according to the gray-scale compensation data and the correction coefficient and carrying out gray-scale compensation on the display picture of the display panel.
In another aspect, the present invention also provides a driving method of a display device, including:
illuminating the display panel;
acquiring a current display image of a display panel, and obtaining gray scale values of all sub-pixels in the current display image;
acquiring gray-scale compensation data according to the current display brightness of the current display image;
obtaining a correction coefficient according to a first slope and a second slope, wherein the first slope is a curve slope of gray scale and voltage under current display brightness, and the second slope is a curve slope of gray scale and voltage under basic display brightness;
according to the gray-scale compensation data and the correction coefficient, obtaining an actual gray-scale compensation value to perform gray-scale compensation on a display picture of the display panel;
and obtaining the actual gray scale value of the current display picture according to the gray scale value of the current display picture and the actual gray scale compensation value.
Compared with the prior art, the display device and the driving method thereof provided by the invention have the advantages that at least the following effects are realized:
when the display panel of the display device displays a picture, gray-scale compensation data are acquired according to the current display brightness of the current display image, a first slope and a second slope are determined, the first slope is a curve slope of gray scale and voltage under the current display brightness, the second slope is a curve slope of gray scale and voltage under the basic display brightness, a correction coefficient is obtained according to the first slope and the second slope, and finally an actual gray-scale compensation value is obtained according to the gray-scale compensation data and the correction coefficient together, so that gray-scale compensation is carried out on the display picture of the display panel, and an actual gray-scale value of the current display picture is obtained according to the gray-scale value of the current display image and the actual gray-scale compensation value.
Of course, it is not necessary for any one product embodying the invention to achieve all of the technical effects described above at the same time.
Other features of the present invention and its advantages will become apparent from the following detailed description of exemplary embodiments of the invention, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.
FIG. 1 is a graph showing the correspondence between gray scale and voltage in PWM mode and DC mode at a luminance of 2nit in the related art;
fig. 2 is a schematic plan view of a display device according to the present invention;
FIG. 3 is a schematic diagram of a pixel circuit according to the present invention;
FIG. 4 is a timing diagram provided by the present invention;
fig. 5 is a schematic plan view of another display device according to the present invention;
fig. 6 is a schematic plan view of another display device according to the present invention;
FIG. 7 is a flow chart of a driving method of a display device according to the present invention;
FIG. 8 is a flow chart of a driving method of a display device according to another embodiment of the present invention;
fig. 9 is a flowchart of a gray-scale compensation data calculation method provided by the invention.
Detailed Description
Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.
The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of exemplary embodiments may have different values.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
In view of the problem that the display device of the related art has poor Mura compensation capability in the DC mode and poor demux compensation in the low brightness, the inventor researches the related art, and referring to fig. 1, fig. 1 is a graph of the correspondence between gray scale and voltage in the PWM mode and the DC mode in the related art when the brightness is 2nit, the abscissa is the gray scale, the ordinate is the source voltage, that is, the data voltage determines the brightness of the sub-pixel on the corresponding data line, 2nit is the display device in the low brightness state, for the PWM mode, the display device is continuously alternated in the bright state, the bright state and the dark state of the DC mode, the light emitting time of the DC mode is long, the driving transistor current is smaller in the same brightness, the screen Mura is serious, and thus the compensation capability of the demand demux is larger. Referring to fig. 1, the compensation offset is stored in the form of gray scale in the related art, and as can be seen from fig. 1, since the gray scale versus voltage curve in the PWM mode is steeper than the gray scale versus voltage curve in the DC mode, that is, the slope of the gray scale versus voltage curve in the PWM mode is greater than the slope of the gray scale versus voltage curve in the DC mode, the gray scale versus voltage curve is related to the light emitting material in the display panel, and the gray scale versus voltage curve is determined when the light emitting material is fixed. Therefore, the voltage change corresponding to the one gray level change in the PWM mode is greater than the voltage change corresponding to the one gray level change in the DC mode, and in fig. 1, the voltage change corresponding to the one gray level change in the PWM mode is 2 times that corresponding to the one gray level change in the DC mode, so that when compensation is performed, the DC mode needs to amplify the compensation offset by a factor much greater than that of the compensation offset in the PWM mode, the ordinate data signal can be compensated to a proper voltage, and the maximum amplification value that can be supported by the driving chip in the related art is 4 times, so that the maximum value that can be supported by the existing driving chip is exceeded, and therefore, when the driving chip is low, the compensation of low-brightness Demura in the DC mode is not good.
In view of the above, the present invention provides a display device and a driving method thereof, which solve the problem of poor visual effect caused by uneven display in a DC dimming mode, and specific embodiments of the display device and the driving method thereof will be described in detail below.
Referring to fig. 2, 3 and 4, fig. 2 is a schematic plan view of a display device according to the present invention, fig. 3 is a pixel circuit according to the present invention, and fig. 4 is a timing chart according to the present invention, where the display device 100 of fig. 2 includes: a display panel 10 including a plurality of sub-pixels P; a first data storage unit 20 for storing gray-scale compensation data; the correction coefficient obtaining unit 30 obtains a correction coefficient according to a first slope and a second slope, the first slope is a slope of a curve of gray scale and voltage at the current display brightness, and the second slope is a slope of a curve of gray scale and voltage at the display brightness; the compensation unit 40 obtains an actual gray-scale compensation value according to the gray-scale compensation data and the correction coefficient to perform gray-scale compensation on the display screen of the display panel 10.
Specifically, the display panel 10 may be an organic light emitting display panel. In the present invention, the display device 100 can effectively compensate for display non-uniformity in a low-brightness state, that is, the average brightness of the display panel 10 is between 2nit and 110nit, or the average brightness of the display panel 10 is between 2nit and 90nit, and the average value of the low-brightness is not specifically limited.
The display panel 10 is shown in fig. 2 to further comprise a non-display area BB surrounding the display area AA, and fig. 2 illustrates the display panel 10 by way of example only with respect to a rectangular display panel 10, and in some other embodiments of the present application, the display panel 10 may also be embodied in other shapes, such as a circular, oval, or shaped structure. Fig. 2 shows only the case where the non-display area BB completely surrounds the display area AA, but the non-display area BB may also partially surround the display area AA (e.g., a water droplet screen), which is not particularly limited herein. Fig. 2 shows only a part of the sub-pixels P in the display area AA, and does not represent the actual number and arrangement of the sub-pixels P contained in the display area AA, and fig. 2 does not represent the actual size of the sub-pixels P, which is merely illustrative.
In this embodiment, the first non-display area BB1 and the second non-display area BB2 are also shown, the first shift register 21 is located in the first non-display area BB1, that is, the first shift register 21 is driven on a single side, so that the width of the first non-display area BB1 in the first direction X can be reduced, a narrow frame is implemented, the first shift register 21 provides the pixel circuit 000 with a light emission control signal Emit, that is, a signal for controlling whether the first transistor M1 and the fifth transistor M5 are turned on, and the second shift register 22 is located in the second non-display area BB2, that is, the second shift register 22 is driven on a single side, so that the width of the second non-display area BB2 in the first direction X can be reduced, the narrow frame is implemented, and the second shift register 22 provides the pixel circuit 000 with the first control signal S1. The positions of the first shift register 21 and the second shift register 22 are not particularly limited as long as the first shift register 21 and the second shift register 22 are located on opposite sides of the non-display area BB, for example, the first shift register 21 is located on the left frame, the second shift register 22 is located on the right frame, or the first shift register 21 is located on the right frame, and the second shift register 22 is located on the left frame. Also shown in fig. 2 is a third shift register 23, the third shift register 23 being located in both the first non-display area BB1 and the second non-display area BB2, i.e. the third shift register 23 is dual-edge driven, the third shift register 23 may provide the second control signal S2 to the pixel circuit 000.
As shown in fig. 3, the pixel driving circuit 000 includes: a first transistor M1 having a control terminal electrically connected to the light emitting signal input terminal, a first terminal electrically connected to the first power signal terminal VDD, and a second terminal electrically connected to the first terminal of the driving transistor M, the first power signal terminal VDD inputting the first power voltage PVDD; a second transistor M2 having a control terminal electrically connected to the second scan signal input terminal S2, a first terminal electrically connected to the data signal input terminal data, and a second terminal electrically connected to the first terminal of the driving transistor M; a driving transistor M having a control terminal electrically connected to the second terminal of the fourth transistor M4, and a first terminal electrically connected to the second terminal of the first transistor M1 and the second terminal of the second transistor M2; a third transistor M3 having a control terminal electrically connected to the second scan signal input terminal S2, a first terminal electrically connected to the second terminal of the fourth transistor M4 and the second terminal of the storage capacitor Cst, and a second terminal electrically connected to the second terminal of the driving transistor M and the first terminal of the fifth transistor M5; a fourth transistor M4 having a control terminal electrically connected to the first scan signal input terminal S1, a first terminal electrically connected to the reference voltage signal input terminal Vref, and a second terminal electrically connected to the control terminal of the driving transistor M; a fifth transistor M5 having a control terminal electrically connected to the light emitting signal input terminal Em, a first terminal electrically connected to the second terminal of the driving transistor M and the second terminal of the third transistor M3, and a second terminal electrically connected to the anode of the light emitting element O; a sixth transistor M6 having a control terminal electrically connected to the second scan signal input terminal, a first terminal electrically connected to the reference voltage signal input terminal, and a second terminal electrically connected to the first terminal of the light emitting element O; a light emitting element O having a first terminal electrically connected to the second terminal of the fifth transistor M5 and the second terminal of the sixth transistor M6, the second terminal electrically connected to the second power signal terminal VEE, and the second power signal terminal VEE inputting the second power voltage PVEE; the first terminal of the storage capacitor Cst is electrically connected to the first power signal terminal VDD, and the second terminal of the storage capacitor Cst is electrically connected to the control terminal of the driving transistor M, the first terminal of the third transistor M3, and the second terminal of the fourth transistor M4.
As shown in fig. 4, in the pixel circuit driving timing including the reset phase t1, the data writing phase t2 and the light emitting phase t3, the reset phase t1, the fourth transistor M4 and the sixth transistor M6 are turned on, the reset signal Vref is written into the first node N1 and the anode of the light emitting element O, respectively, the first node N1 is reset, the driving transistor M is turned on in response to the potential of the first node N1, the reset signal Vref is written into the anode of the light emitting element O, and the anode of the light emitting element O is reset; in the data writing stage t2, the second transistor M2 is turned on, and the third transistor M3 is turned on, and the data signal Vdata is written into the first node N1 through the driving transistor M; in the light emitting stage t3, the first transistor M1 and the fifth transistor M5 are turned on under the control of the light emission control signal Emit, and the light emitting element O emits light when a current is formed between the first power signal terminal VDD and the second power signal terminal VEE. Therefore, the light emitting time in the light emitting stage is determined by the light emitting control signal Emit, and the light emitting control signal Emit is kept at a low potential in the DC mode, so that the first transistor M1 and the fifth transistor M5 are kept on.
The first data storage unit 20 of the present invention is used for storing gray-scale compensation data, and it can be understood that the gray-scale compensation can be performed by Demura, and the brightness of the pixel point can be corrected by gray-scale compensation, so as to improve the Mura phenomenon. Gray scale compensation improves brightness uniformity by changing the gray scale of the pixel. The process of Demura is to shoot the Mura condition of gray-scale picture through the camera, in the input image is single gray-scale picture, according to the brightness of the central area of the panel, extract and correct the Mura through some algorithms, in order to increase certain gray-scale compensation value to the pixel of the dark area, and reduce certain gray-scale compensation value to the pixel of the bright area, realize the improvement of Mura phenomenon. The compensation values (or demux data) for all pixels can be made into a demux table for processing by the hardware, i.e. the gray-scale compensation data is stored in the first data storage unit 20 and is called when the compensation is performed subsequently.
When the light emitting material in the display panel 10 is determined, the relation curve between gray scale and voltage is determined, and then the slope of the relation curve between gray scale and voltage is determined, the correction coefficient obtaining unit 30 needs to obtain a first slope and a second slope, and then the correction coefficient is obtained by calculating according to the first slope and the second slope.
The compensation unit 40 is coupled to the first data storage unit 20 and the correction coefficient obtaining unit 30, and performs gray-scale compensation on the display screen of the display panel 10 according to the gray-scale compensation data and the correction coefficient obtained by the correction coefficient obtaining unit 30, and obtains the actual gray-scale compensation value after the gray-scale compensation data is obtained by the first data storage unit 20 and the correction coefficient obtained by the correction coefficient obtaining unit 30, thereby performing gray-scale compensation on the display screen of the display panel 10.
According to the invention, the correction coefficient is added when gray level compensation is carried out, and is determined according to the voltage change relation when gray level is changed under the current display brightness and the basic display brightness, and the correction coefficient can amplify the multiple of gray level compensation, so that the optical compensation capability under the DC dimming mode is enhanced, and the problem of poor visual effect caused by uneven display under the DC dimming mode is solved.
In some alternative embodiments, with continued reference to fig. 2, the correction coefficient obtaining unit 30 obtains the correction coefficient according to the first slope and the second slope includes: α=α1/α2, where α is the correction coefficient, α1 is the first slope, and α2 is the second slope.
Specifically, when the display panel 10 displays the same display screen, if the brightness of the display screen changes with the change of the brightness bar when the brightness bar is slid, a set of gray scale-brightness relationship curves is generated by the brightness bar band of one display panel 10, and the brightness corresponding to the gray scale is different under different brightness bar bands, that is, the data signal Vdata voltage corresponding to the same gray scale under different brightness bar bands is also different. The first slope alpha 1 is the slope of the curve of the gray scale and the voltage under the current display brightness, the second slope alpha 2 is the slope of the curve of the gray scale and the voltage under the basic display brightness, the ratio of the first slope alpha 1 to the second slope alpha 2 is that the current display brightness is converted into the relation between the gray scale and the voltage under the basic display brightness, the compensation is carried out under the same basic display brightness, and the multiple of the gray scale compensation is amplified.
In some alternative embodiments, with continued reference to fig. 2, the compensation unit 40 performs gray-scale compensation on the display screen of the display panel 10 according to the gray-scale compensation data and the correction coefficient to obtain an actual gray-scale compensation value, and the specific compensation unit 40 calculates the actual gray-scale compensation value offset_out according to offset_out=offset×gain×α, where α is the correction coefficient.
The gray-scale compensation data of the compensation value offset and the correction coefficient Gain are stored in the first data storage unit 20. In the related art, the actual gray-scale compensation value offset_out is only equal to the product of the compensation coefficient offset and the correction coefficient Gain, and the voltage variation is not regulated according to the gray scale.
In some alternative embodiments, with continued reference to fig. 2, the actual display gray level of the display screen of the display panel 10 is equal to the sum of the gray level value of the current display screen and the actual gray level compensation value.
The actual gray-scale compensation value offset_out=offset×gain×α, and the actual display gray-scale gray_out=gray_now+offset_out=gray_now+offset×gain×α of the display screen.
Specifically, the brightness of each sub-pixel at different gray scales is photographed, the compensation coefficient of each sub-pixel of the display panel 10 at a certain gray scale (for example, 64 gray scales or 32 gray scales) can be calculated according to the brightness data of each sub-pixel at different gray scales, the compensation coefficient can be positive or negative, when each sub-pixel displays the brightness of 0-255 gray scales on the display panel 10, each sub-pixel respectively superimposes the calculated compensation coefficient of the corresponding sub-pixel, for example, the compensation coefficient of a certain red sub-pixel is-7, if the red sub-pixel displays 7 gray scales according to the image requirement, the correction coefficient Gain set by the 7 gray scales is 1, and if the correction coefficient calculated according to the first slope and the second slope is 2, the actual display is 7+ (-7×1×2) = -7 red; similarly, if the sub-pixel displays 64 red according to the image requirement, and the correction coefficient Gain set by 64 gray scale is 0.5, the correction coefficient is calculated according to the first slope and the second slope to be 2, the brightness of 64+ (-7×0.5×2) =57 red is actually displayed.
According to the invention, the correction coefficient is added when gray level compensation is carried out, and is determined according to the voltage change relation when gray level is changed under the current display brightness and the basic display brightness, and the correction coefficient can amplify the multiple of gray level compensation, so that the optical compensation capability under the DC dimming mode is enhanced, and the problem of poor visual effect caused by uneven display under the DC dimming mode is solved.
In some alternative embodiments, referring to fig. 5, fig. 5 is a schematic plan view of still another display device according to the present invention, and further includes a display driver chip IC, where the display driver chip IC includes a lookup table, and correction coefficients are stored in the lookup table.
Optionally, the display driver chip IC is multiplexed into the correction coefficient obtaining unit 30, and the correction coefficients are stored in a lookup table of the display driver chip IC, that is, the correction coefficients corresponding to different brightness bands can be calculated and burnt into the lookup table of the display driver chip IC after Gamma adjustment is completed, and the correction coefficients are directly adjusted from the display driver chip IC when gray-scale compensation is to be performed, so that compensation can be performed rapidly, and compensation efficiency is improved.
In some alternative embodiments, referring to fig. 6, fig. 6 is a schematic plan view of another display device provided by the present invention, and further includes a flash memory chip 50 and a display driver chip IC, the first data storage unit 20 is multiplexed into the flash memory chip 50, the flash memory chip 50 is electrically connected to the display driver chip IC, and the display driver chip IC invokes gray-scale compensation data.
Optionally, the flash memory chip 50 is disposed in the display device 100, and gray-scale compensation data such as the compensation coefficient offset and the correction coefficient Gain are burned in the flash memory chip 50, and when gray-scale compensation is to be performed, the gray-scale compensation data is read from the flash memory chip 50, so that compensation can be performed rapidly, and compensation efficiency is improved.
Based on the same inventive concept, the present invention further provides a driving method of a display device, applied to the display device 100, where the driving method of the display device 100 refers to fig. 7, and fig. 7 is a flowchart of the driving method of the display device provided by the present invention, as shown in fig. 7, including the following steps:
s1: illuminating the display panel;
s2: acquiring a current display image of a display panel, and obtaining gray scale values of all sub-pixels in the current display image;
s3: acquiring gray-scale compensation data according to the current display brightness of the current display image;
s4: obtaining correction coefficients according to a first slope and a second slope, wherein the first slope is a curve slope of gray scale and voltage under the current display brightness, and the second slope is a curve slope of gray scale and voltage under the display brightness;
s5: according to the gray-scale compensation data and the correction coefficient, obtaining an actual gray-scale compensation value to perform gray-scale compensation on a display picture of the display panel;
s6: and obtaining the actual gray scale value of the current display picture according to the gray scale value of the current display picture and the actual gray scale compensation value.
In the driving method, a display panel is firstly lightened, the gray scale value of each sub-pixel in a current display image is obtained according to the image to be displayed by the display panel, the gray scale value of each sub-pixel in the current display image is available, and the brightness strip of the current image can be obtained; acquiring gray-scale compensation data according to the current display brightness of the current display image, wherein the gray-scale compensation data comprises a compensation value offset and a correction coefficient gain; then, the correction coefficient of the current display image needs to be obtained, wherein the correction coefficient is obtained according to a first slope and a second slope, the first slope is the slope of a curve of gray scale and voltage under the current display brightness, the second slope is the slope of the curve of gray scale and voltage under the basic display brightness, in the related technology, when gray scale is compensated, only a compensation value offset and a correction coefficient Gain are utilized, and the correction coefficient is added when gray scale compensation is carried out, and is the correction coefficient determined by the voltage change relation when the gray scale under the current display brightness and the basic display brightness is changed, and the correction coefficient can amplify the multiple of the gray scale compensation, so that the optical compensation capability under the DC dimming mode is enhanced, and the problem of poor visual effect caused by uneven display under the DC dimming mode is solved.
In some alternative embodiments, referring to fig. 8, fig. 8 is a flowchart of a driving method of a display device according to the present invention, where obtaining an actual gray-scale value of a current display image according to a gray-scale value and an actual gray-scale compensation value includes:
Grey_out＝Grey_Now+offset_out，
the gray_out is the actual gray level value of the current display picture, the gray_now is the gray level value of the current display picture, and the offset_out is the actual gray level compensation value.
Specifically, the brightness of each sub-pixel at different gray scales is shot, the compensation coefficient of each sub-pixel of the display panel at a certain gray scale (for example, 64 gray scales or 32 gray scales) can be calculated according to the brightness data of each sub-pixel at different gray scales, the compensation coefficient can be positive or negative, when each sub-pixel displays the brightness of 0-255 gray scales on the display panel, each sub-pixel respectively superimposes the calculated compensation coefficient of the corresponding sub-pixel, for example, if the red sub-pixel displays 7 gray scales according to the image requirement, and the actual gray scale compensation value offset_out is calculated to be-14, the actual display is 7+ (-14) = -7 red; similarly, if the sub-pixel displays 64 red steps according to the image requirement, and the calculated actual gray-scale compensation value offset_out is-7, the actual display is 64+ (-7) =57 red brightness.
The actual display gray scale of the display picture of the display panel is equal to the sum of the gray scale value of the current display picture and the actual gray scale compensation value, and the gray scale compensation is carried out on the current display picture, so that the problem of poor visual effect caused by uneven display is solved.
In some alternative embodiments, with continued reference to FIG. 8, the actual gray level compensation value offset_out is calculated using the following method:
offset_out＝offset×Gain×α，
the gray-scale compensation data includes a compensation value offset and a correction coefficient Gain, and α is a correction coefficient.
In the related art, the actual gray-scale compensation value offset_out is only equal to the product of the compensation coefficient offset and the correction coefficient Gain, and the voltage variation is not regulated according to the gray scale.
In some alternative embodiments, with continued reference to fig. 1 and 8, the display driver IC stores gray-scale versus voltage curves for different display brightness, with gray-scale on the abscissa and voltage on the ordinate.
It can be understood that, in fig. 1, only the gray scale and voltage relation curve under the brightness of 2nit is taken as an example, when the luminescent material is fixed, the gray scale and voltage relation curve under the different display brightness is also determined, and the gray scale and voltage relation curve under the different display brightness is stored in the display driving chip IC, so that the gray scale compensation can be carried out at any time from the display driving chip IC, and the efficiency of the gray scale compensation can be improved.
In some alternative embodiments, with continued reference to fig. 1 and 8, deriving the correction factor from the first slope and the second slope includes: α=α1/α2, where α is the correction coefficient, α1 is the first slope, and α2 is the second slope;
the first slope α1 and the second slope α2 are obtained according to the following method:
α1＝(Grey_Low_V_Base-Grey_High_V_Base)/(Grey_High-Grey_Low)，α2＝(Grey_Low_V_Now-Grey_High_V_Now)/(Grey_High-Grey_Low)，
the gray_high is a first gray level, the gray_low is a second gray level, the first gray level is larger than the second gray level, the gray_low_V_Base is used as a basis to display the voltage corresponding to the first gray level in the brightness, and the gray_high_V_Base is used as a basis to display the voltage corresponding to the second gray level in the brightness; grey_Low_V_Now is the voltage corresponding to the first gray level in the current display brightness, and Grey_high_V_Now is the voltage corresponding to the second gray level in the current display brightness.
It should be noted that, when the slope of the gray-scale-voltage relationship curve is taken, the abscissa cannot take a region where the slope suddenly increases, such as a region where the gray-scale value is greater than 7 when the gray-scale value is calculated because the voltage suddenly increases when the gray-scale value is less than 7 in fig. 1.
In the present invention, it can be understood that, the zero degree of the different brightness bands is different, so the brightness gray levels are different, so the first gray level grey_high and the second gray level grey_low parameters need to be set, and the parameters can be different according to the different brightness bands, or can be set to the same parameters on the premise of ensuring that all brightness bands are covered with the brightness gray levels.
In some alternative embodiments, referring to fig. 9, fig. 9 is a flowchart of a method for calculating gray-scale compensation data according to the present invention, where the gray-scale compensation data shown in fig. 9 is obtained according to the following method:
s201, setting an average brightness value of a display panel;
s202, photographing to obtain brightness data of each sub-pixel of the current display brightness of the display panel under a plurality of test gray scales;
s203, calculating a compensation coefficient of the appointed gray scale of the basic display brightness of each sub-pixel of the display panel according to different brightness data of each sub-pixel;
s204, the compensation coefficient is burnt into the flash memory chip 50.
Specifically, step S201: the average luminance value of the display image is set, wherein the average luminance value of the display image is selected, for example, a display image with average luminance of 32nit can be selected as a basis, the display image with other luminance can be calculated according to a linear difference method, the average luminance value of the set display image is not specifically limited, and the average luminance value of the set display image can be selected to be 2nit, 10nit, 26nit, 135nit and the like.
Step S202: the brightness of each sub-pixel in the display image is obtained, the brightness difference between the brightness of each sub-pixel and the average brightness value is calculated, the brightness difference is converted into a gray level difference, further, the brightness of each sub-pixel is obtained, for example, the brightness of the sub-pixel is 19nit, 20nit, 19nit, 23nit, 28nit, 26nit, 30nit … …, etc., and the average brightness value is set to 26nit, then the brightness difference is 7nit, 6nit, 7nit, 3nit, 2nit, 0, 4nit … …, and the brightness difference is converted into a gray level difference, for example, 7, 6, 7, 3, 2, 0, -4 … …, which is of course only illustrative, and is not limited as an actual product.
Step S203: the compensation coefficient of the appointed gray scale of the basic display brightness of each sub-pixel of the display panel is calculated according to different brightness data of each sub-pixel, for example, the gray scale difference values are respectively 7, 6, 7, 3, 2, 0 and-4 … ….
In step S204, the compensation coefficient is burned into the flash memory chip 50, so that the compensation coefficient can be directly read from the flash memory chip 50 when gray-scale compensation is performed, the gray-scale compensation efficiency of the display panel is improved, and the compensation coefficient is not needed to be burned into the display driver chip IC, so that the data amount stored in the display driver chip IC can be reduced, and the working efficiency of the display driver chip IC is improved.
In some alternative embodiments, with continued reference to FIG. 5, the correction coefficients are burned into the display driver chip IC, or the display driver chip IC calculates the correction coefficients in real time.
Optionally, the correction coefficient is stored in the display driving chip IC, a lookup table is first built in the display driving chip IC, the correction coefficient is stored in the lookup table, that is, the correction coefficients corresponding to the bands with different brightness can be calculated and burnt into the lookup table of the display driving chip IC after Gamma debugging is completed, and the correction coefficients are directly called from the display driving chip IC when gray level compensation is to be performed, so that compensation can be performed rapidly, and compensation efficiency is improved.
Alternatively, the correction coefficient may be calculated in real time by the display driver IC, which is not shown in the figure, so that the correction coefficient data does not need to be stored in the display driver IC in a large amount, and the correction coefficient data is calculated in real time when gray level compensation is performed, so that the amount of data stored in the display driver IC can be reduced, and the working efficiency of the display driver IC is improved.
As can be seen from the above embodiments, the display device and the driving method thereof provided by the present invention at least achieve the following beneficial effects:
when the display panel of the display device displays a picture, gray-scale compensation data are acquired according to the current display brightness of the current display image, a first slope and a second slope are determined, the first slope is a curve slope of gray scale and voltage under the current display brightness, the second slope is a curve slope of gray scale and voltage under the basic display brightness, a correction coefficient is obtained according to the first slope and the second slope, and finally an actual gray-scale compensation value is obtained according to the gray-scale compensation data and the correction coefficient together, so that gray-scale compensation is carried out on the display picture of the display panel, and an actual gray-scale value of the current display picture is obtained according to the gray-scale value of the current display image and the actual gray-scale compensation value.
While certain specific embodiments of the invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims (13)

1. A display device, comprising:
a display panel including a plurality of sub-pixels;
a first data storage unit for storing gray-scale compensation data;
the correction coefficient acquisition unit is used for obtaining a correction coefficient according to a first slope and a second slope, wherein the first slope is a curve slope of gray scale and voltage under current display brightness, and the second slope is a curve slope of gray scale and voltage under basic display brightness;
and the compensation unit is used for obtaining an actual gray-scale compensation value according to the gray-scale compensation data and the correction coefficient and carrying out gray-scale compensation on the display picture of the display panel.
2. The display device of claim 1, wherein deriving the correction factor from the first slope and the second slope comprises:
α=α1/α2, where α is the correction coefficient, α1 is the first slope, and α2 is the second slope.
3. The display device according to claim 1, wherein obtaining an actual gray-scale compensation value from the gray-scale compensation data and the correction coefficient to perform gray-scale compensation on a display screen of the display panel comprises:
the actual gray-scale compensation value offset_out is calculated by the following method:
offset_out＝offset×Gain×α，
the gray-scale compensation data comprises a compensation value offset and a correction coefficient Gain, and alpha is the correction coefficient.
4. A display device according to claim 3, wherein the actual display gray level of the display screen of the display panel is equal to the sum of the gray level value of the current display screen and the actual gray level compensation value.
5. The display device of claim 1, further comprising a display driver chip including a look-up table, the correction coefficients being stored in the look-up table.
6. The display device of claim 1, further comprising a flash memory chip and a display driver chip, wherein the first data storage unit is multiplexed into the flash memory chip, wherein the flash memory chip is electrically connected to the display driver chip, and wherein the display driver chip invokes the grayscale compensation data.
7. A driving method of a display device, comprising:
illuminating the display panel;
acquiring a current display image of a display panel, and obtaining gray scale values of all sub-pixels in the current display image;
acquiring gray-scale compensation data according to the current display brightness of the current display image;
obtaining a correction coefficient according to a first slope and a second slope, wherein the first slope is a curve slope of gray scale and voltage under current display brightness, and the second slope is a curve slope of gray scale and voltage under basic display brightness;
according to the gray-scale compensation data and the correction coefficient, obtaining an actual gray-scale compensation value to perform gray-scale compensation on a display picture of the display panel;
and obtaining the actual gray scale value of the current display picture according to the gray scale value of the current display picture and the actual gray scale compensation value.
8. The method of driving a display device according to claim 7, wherein obtaining an actual gray-scale value of a current display screen from the gray-scale value and the actual gray-scale compensation value of the current display image comprises:
Grey_out＝Grey_Now+offset_out，
the gray_out is an actual gray level value of the current display picture, the gray_now is the gray level value of the current display picture, and the offset_out is an actual gray level compensation value.
9. The method for driving a display device according to claim 8, wherein,
the actual gray-scale compensation value offset_out is calculated by the following method:
offset_out＝offset×Gain×α，
the gray-scale compensation data comprises a compensation value offset and a correction coefficient Gain, and alpha is the correction coefficient.
10. The driving method of a display device according to claim 7, wherein the display driving chip stores gray-scale and voltage relationship curves under different display brightness, and an abscissa is gray-scale and an ordinate is voltage.
11. The method of driving a display device according to claim 10, wherein obtaining the correction coefficient based on the first slope and the second slope comprises: α=α1/α2, where α is the correction coefficient, α1 is a first slope, and α2 is a second slope;
the first slope α1 and the second slope α2 are obtained according to the following method:
α1＝(Grey_Low_V_Base-Grey_High_V_Base)/(Grey_High-Grey_Low)，
α2＝(Grey_Low_V_Now-Grey_High_V_Now)/(Grey_High-Grey_Low)，
the gray_high is a first gray level, the gray_low is a second gray level, the first gray level is larger than the second gray level, the gray_low_V_Base is used as a basis to display the voltage corresponding to the first gray level in the brightness, and the gray_high_V_Base is used as a basis to display the voltage corresponding to the second gray level in the brightness; grey_Low_V_Now is the voltage corresponding to the first gray level in the current display brightness, and Grey_high_V_Now is the voltage corresponding to the second gray level in the current display brightness.
12. The driving method of a display device according to claim 7, wherein the gray-scale compensation data is obtained according to the following method:
setting an average brightness value of the display panel;
photographing to obtain brightness data of each sub-pixel of the current display brightness of the display panel under a plurality of test gray scales;
calculating a compensation coefficient of the appointed gray scale of the basic display brightness of each sub-pixel of the display panel according to different brightness data of each sub-pixel;
and burning the compensation coefficient into the flash memory chip.
13. The driving method of the display device according to claim 7, wherein the correction coefficient is burned in a display driving chip or the display driving chip calculates the correction coefficient in real time.
CN202310213082.7A 2023-03-06 2023-03-06 Display device and driving method thereof Pending CN116229894A (en)

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