CN112489591B - Driving method and device of display panel - Google Patents
Driving method and device of display panel Download PDFInfo
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- CN112489591B CN112489591B CN202011409827.XA CN202011409827A CN112489591B CN 112489591 B CN112489591 B CN 112489591B CN 202011409827 A CN202011409827 A CN 202011409827A CN 112489591 B CN112489591 B CN 112489591B
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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]
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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
- 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
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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
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/0626—Adjustment of display parameters for control of overall brightness
Abstract
The invention discloses a driving method and a driving device of a display panel. The display panel includes a pixel circuit, the method includes: setting a first initialization voltage according to the display brightness value; a first initialization voltage is provided to the pixel circuit to initialize the light emitting module in the pixel circuit. By setting the first initialization voltage according to the display brightness value, when the display brightness value is lower, the first initialization voltage is set to be larger, and the leakage current of the driving current to the transistor of the light-emitting device through the initialization voltage can be reduced in the light-emitting stage of the pixel circuit, so that the leakage current phenomenon in the pixel circuit can be reduced, the current difference of the pixel circuit for driving the light-emitting device to emit light, caused by the leakage current characteristic of the transistor, is reduced, and the brightness uniformity of the display panel is improved.
Description
Technical Field
The embodiment of the invention relates to the technical field of display, in particular to a driving method and a driving device of a display panel.
Background
As the display performance requirements of the display device increase, the brightness uniformity requirements of the display panel are higher and higher. Due to the performance difference of the transistors forming the pixel circuit in the display panel, the brightness uniformity of the display panel is poor, and the experience effect of a user is reduced.
Disclosure of Invention
The invention provides a driving method and a driving device of a display panel, which are used for improving the brightness uniformity of the display panel.
In a first aspect, an embodiment of the present invention provides a driving method for a display panel, where the display panel includes a pixel circuit; the method comprises the following steps:
setting a first initialization voltage according to the display brightness value;
and providing the first initialization voltage to the pixel circuit to initialize a light emitting module in the pixel circuit.
In the above process, when the display brightness value is relatively low, the first initialization voltage is set to be relatively high, and the leakage current of the driving current to the transistor of the light emitting device through the initialization voltage provided by the transistor can be reduced in the light emitting stage of the pixel circuit, so that the leakage current phenomenon in the pixel circuit can be reduced, the current difference of the pixel circuit for driving the light emitting device to emit light caused by the leakage current characteristic of the transistor is reduced, and the brightness uniformity of the display panel is improved.
Optionally, the setting the first initialization voltage according to the display brightness value includes:
dividing a plurality of display brightness value intervals according to the range of the display brightness values, wherein each display brightness value interval corresponds to the brightness level of one display brightness value;
setting a corresponding first initialization voltage constant according to each brightness grade; wherein the first initialization voltage constant increases as the brightness level of the display brightness value decreases;
determining a first initialization voltage corresponding to each display brightness value according to the first initialization voltage constant and the number of display brightness values in the brightness level; wherein the first initialization voltage increases when the display brightness value decreases.
When the brightness level of the display brightness value is set to be reduced, the first initialization voltage constant is increased, so that the leakage current of the driving current to the transistor of the light-emitting device through the initialization voltage can be reduced in the light-emitting stage of the pixel circuit, the leakage current phenomenon in the pixel circuit can be reduced, the current difference of the driving light-emitting device of the pixel circuit, caused by the leakage current characteristic of the transistor, in the light-emitting stage of the pixel circuit is reduced, and the brightness uniformity of the display panel is improved.
Optionally, within a brightness level of the display brightness value, the first initialization voltage and the display brightness value have a linear relationship.
By setting the display brightness value in the brightness level, the first initialization voltage and the display brightness value are in a linear relation, so that the first initialization voltage corresponding to different display brightness values can be easily obtained, and calculation is facilitated.
Optionally, after setting the first initialization voltage according to the display brightness value, the method further includes:
and setting the power supply voltage of the pixel circuit according to the first initialization voltage to enable the voltage difference between two ends of a light emitting module of the pixel circuit to be smaller than or equal to a first threshold value.
The power supply voltage of the pixel circuit is set according to the first initialization voltage, so that the voltage difference between two ends of the light emitting module of the pixel circuit is smaller than or equal to the first threshold value, the requirement of higher data voltage when the display panel displays a black picture in a light emitting stage can be avoided, and the probability of incomplete initialization of the data voltage can be reduced on the basis of ensuring that the display panel can normally display the black picture.
Optionally, after setting the first initialization voltage according to the display brightness value, the method further includes:
setting a bright state voltage according to the display brightness value; wherein the bright state voltage increases in accordance with a decrease in the display brightness value;
and determining data voltages corresponding to different display brightness values according to the bright-state voltage and the dark-state voltage.
In the above process, when the display brightness value is gradually decreased, the dark-state voltage remains unchanged, and the bright-state voltage is increased along with the decrease of the display brightness value, so that the gamma precision is gradually increased, and the precision of the data voltage can be further improved. The brightness uniformity of the display panel is improved under the condition that the driving current provided by the pixel circuit is relatively small.
Optionally, after initializing the light emitting module in the pixel circuit, the method further includes:
and providing the data voltage to the pixel circuit, and writing data into a storage module in the pixel circuit.
Optionally, after writing data to the memory module in the pixel circuit, the method further includes:
and providing a light-emitting control signal to the pixel circuit to control the light-emitting module in the pixel circuit to emit light.
Optionally, when initializing the light emitting module in the pixel circuit, the method further includes:
and providing a second initialization voltage to the pixel circuit to initialize the storage module in the pixel circuit.
In a second aspect, an embodiment of the present invention further provides a driving apparatus for a display panel, where the display panel includes a pixel circuit, and the driving apparatus for the display panel includes:
a first initialization voltage setting unit for setting a first initialization voltage according to a display brightness value;
the first initialization voltage providing unit is used for providing the first initialization voltage to the pixel circuit and initializing a light emitting module in the pixel circuit.
The first initialization voltage is set by the first initialization voltage setting unit according to the display brightness value, when the display brightness value is lower, the first initialization voltage is set to be larger, and the leakage current of the driving current to the transistor of the light-emitting device through the supply of the initialization voltage can be reduced in the light-emitting stage of the pixel circuit, so that the leakage current phenomenon in the pixel circuit can be reduced, the current difference of the pixel circuit for driving the light-emitting device to emit light caused by the leakage current characteristic of the transistor is reduced, and the brightness uniformity of the display panel is improved.
Optionally, the first initialization voltage setting unit includes:
a display brightness value interval dividing subunit, configured to divide a plurality of display brightness value intervals according to the range of the display brightness values, where each display brightness value interval corresponds to a brightness level of one display brightness value;
the first initialization voltage constant setting subunit is used for setting a corresponding first initialization voltage constant according to each brightness grade; wherein the first initialization voltage constant increases as the brightness level of the display brightness value decreases;
a first initialization voltage determining unit, configured to determine, according to the first initialization voltage constant and the number of display luminance values in the luminance level, a first initialization voltage corresponding to each display luminance value; wherein the first initialization voltage increases when the display brightness value decreases.
According to the invention, the first initialization voltage is set according to the display brightness value, when the display brightness value is lower, the first initialization voltage is set to be larger, and the leakage current of the driving current to the transistor of the light-emitting device through the initialization voltage can be reduced in the light-emitting stage of the pixel circuit, so that the leakage current phenomenon in the pixel circuit can be reduced, the current difference of the pixel circuit for driving the light-emitting device to emit light caused by the leakage current characteristic of the transistor is reduced, and the brightness uniformity of the display panel is improved.
Drawings
Fig. 1 is a schematic diagram of a partial structure of a conventional pixel circuit;
fig. 2 is a schematic flowchart of a driving method of a display panel according to an embodiment of the invention;
fig. 3 is a schematic structural diagram of a pixel circuit according to an embodiment of the present invention;
FIG. 4 is a diagram illustrating brightness level division of display brightness values according to an embodiment of the present invention;
FIG. 5 is a flowchart illustrating another driving method of a display panel according to an embodiment of the present invention;
fig. 6 is a flowchart illustrating another driving method of a display panel according to an embodiment of the invention;
fig. 7 is a flowchart illustrating another driving method of a display panel according to an embodiment of the invention;
fig. 8 is a schematic structural diagram of a driving apparatus of a display panel according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic diagram of a partial structure of a conventional pixel circuit. As shown in fig. 1, the pixel circuit includes a driving transistor DTFT, a switching transistor STFT, and a light emitting diode D1. In the initialization phase, the switching transistor STFT is turned on to transmit the initialization voltage VREFN to the anode of the light emitting diode D1, thereby initializing the light emitting diode D1. In the light emitting stage, the driving transistor DTFT forms a driving current to drive the light emitting diode D1 to emit light. Since the initialization voltage VREFN is relatively small, when the pixel circuit is in the light emitting stage, the driving current provided by the driving transistor DTFT passes through the switching transistor STFT, causing a leakage current. The different performance of the switching transistor STFT in different pixel circuits in the display panel causes different leakage current of the switching transistor STFT in different pixel circuits, which causes different driving current for driving the light emitting diode D1 to emit light, resulting in different luminance brightness of the light emitting diode D1 in different pixel circuits, and poor luminance uniformity of the display panel. When the display panel displays at low brightness, the driving current formed by the driving transistor DTFT is relatively small, and the performance of the switching transistor STFT in different pixel circuits is different, so that the leakage current formed by shunting the driving current through the switching transistor STFT is different, which results in a relatively large shunting difference of the driving current through the light emitting diode D1 in different pixel circuits, and poor brightness uniformity of the display panel.
In view of the above technical problems, embodiments of the present invention provide a driving method for a display panel. Fig. 2 is a flowchart illustrating a driving method of a display panel according to an embodiment of the present invention, for driving the display panel. As shown in fig. 2, the method includes:
s110, setting a first initialization voltage according to the display brightness value;
specifically, the display panel includes a pixel circuit for driving the light emitting device to emit light. Fig. 3 is a schematic structural diagram of a pixel circuit according to an embodiment of the present invention. As shown in fig. 3, the pixel circuit includes 7T1C, that is, the pixel circuit includes a driving transistor Tdr, a first transistor T1, a second transistor T2, a third transistor T3, a fourth transistor T4, a fifth transistor T5, a sixth transistor T6, and a storage capacitor Cst. A gate of the driving transistor Tdr is connected to a first pole of the storage capacitor Cst, a second pole of the fourth transistor T4 and a second pole of the fifth transistor T5, a first pole of the driving transistor Tdr is connected to a second pole of the first transistor T1 and a second pole of the second transistor T2, a second pole of the driving transistor Tdr is connected to a first pole of the third transistor T3 and a first pole of the fourth transistor T4, a first pole of the first transistor T1 is connected to the data voltage input terminal VDATA, a gate of the first transistor T1 and a gate of the fourth transistor T4 are connected to the second SCAN signal input terminal SCAN2, a gate of the second transistor T2 and a gate of the third transistor T3 are connected to the emission control signal EM input terminal, a first pole of the second transistor T2 and a second pole of the storage capacitor Cst are connected to the first power supply signal input terminal VREF2, a second pole of the third transistor T3 is connected to the emission control signal E1, and a second pole of the fifth transistor T5 is connected to the initialization signal input terminal VREF2, a gate of the fifth transistor T5 and a gate of the sixth transistor T6 are connected to the first SCAN signal input terminal SCAN1, a first pole of the sixth transistor T6 is connected to the first initialization signal input terminal VREF1, a second pole of the sixth transistor T6 is connected to an anode of the light emitting device E1, and a cathode of the light emitting device E1 is connected to the second power signal input terminal VSS.
In the operation of the pixel circuit, the fifth transistor T5 and the sixth transistor T6 may be controlled to be turned on by a first SCAN signal provided from the first SCAN signal input terminal SCAN1, a first initialization signal provided from the first initialization signal input terminal VREF1 is transmitted to the anode of the light emitting device E1 through the sixth transistor T6, and a second initialization signal provided from the second initialization signal input terminal VREF2 is transmitted to the first electrode of the storage capacitor Cst through the fifth transistor T5, so that the storage capacitor Cst and the light emitting device E1 are initialized. Then, the first transistor T1 and the fourth transistor T4 are controlled to be turned on by the second SCAN signal supplied from the second SCAN signal input terminal SCAN2, the data voltage supplied from the data voltage input terminal VDATA is written to the gate of the driving transistor Tdr through the first transistor T1, the driving transistor Tdr and the fourth transistor T4, and the data voltage is stored through the storage capacitor Cst, and the writing of the data voltage and the threshold compensation of the driving transistor Tdr are completed. And finally, the second transistor T2 and the third transistor T3 are controlled to be turned on by a light-emitting control signal provided by a light-emitting control signal input end EM, so that the driving transistor Tdr forms a driving current according to the data voltage and outputs the driving current to the light-emitting device E1 to drive the light-emitting device E1 to emit light, thereby realizing the display of the display panel.
A Display Brightness Value (DBV) is used to indicate the brightness level of the Display panel, and different brightness levels correspond to different gamma curves. The gamma curve can determine the display brightness corresponding to different gray scales, and the different display brightness corresponds to different data voltages, so the gamma curve can determine the data voltages corresponding to different gray scales. When the brightness levels of the display brightness values are different, the display brightness corresponding to the maximum gray scale in the display panel is different, and the data voltages are different, so that the gamma curves are different, and the data voltages corresponding to the same gray scale in the display panel are different. When the display brightness value is set to the maximum brightness level, in the gamma curve, the data voltage corresponding to the maximum gray scale of the display panel is the limit data voltage that the display panel can provide. For example, the display panel displays gray levels of 0-255, and the maximum brightness level of the display brightness values corresponds to the minimum data voltage provided by the display panel for the 255 gray levels. When the transistors in the pixel circuit are P-type transistors, the data voltage corresponding to the maximum gray scale in the display panel is the minimum data voltage that the display panel can provide. The larger the brightness level of the display brightness value is, the smaller the data voltage corresponding to the maximum gray scale in the display panel is, and the smaller the data voltage corresponding to the same gray scale in the display panel is under the condition that the brightness level of the display brightness value is smaller, the larger the driving current formed by the pixel circuit according to the data voltage is, and the brighter the display brightness of the display panel is, so that the brightness of the display panel can be adjusted by adjusting the brightness level of the display brightness value.
Illustratively, the display brightness value can represent different brightness values of the display panel by 12 bits, which is 4096 steps, i.e., the display brightness value has a value range of 0 to 4095. The range of display brightness values can be divided into different intervals, each interval corresponding to a brightness level and different gamma curves. Fig. 4 is a schematic diagram of luminance level division for displaying luminance values according to an embodiment of the present invention. The abscissa is a numerical value of the display brightness value, and the ordinate is a ratio of the data voltage corresponding to the maximum gray scale to the limit data voltage which can be provided by the display panel when the display brightness value is different. As shown in fig. 4, the display luminance value may be divided into 10 luminance levels, each luminance level corresponds to a gamma curve, and the ratio of the data voltage corresponding to the maximum gray scale in different gamma curves to the limit data voltage that can be provided by the display panel is different, that is, the data voltages corresponding to the maximum gray scale in different gamma curves are different, so that the data voltages corresponding to the same gray scale in the display panel are different. When the brightness level of the display brightness value is increased, the ratio of the data voltage corresponding to the maximum gray scale in the gamma curve corresponding to the brightness level to the limit data voltage which can be provided by the display panel is larger, the data voltage corresponding to the maximum gray scale in the gamma curve is closer to the limit data voltage which can be provided by the display panel, and the data voltage corresponding to the same gray scale in the display panel is smaller, so that the driving current formed by the pixel circuit according to the data voltage is larger, and the display brightness of the display panel is brighter.
In the display process of the display panel, referring to fig. 2 and 3, the first initialization voltage is transmitted to the first pole of the sixth transistor T6 through the first initialization signal input terminal VREF 1. The sixth transistor T6 has a leakage current in an off state due to the performance characteristics of the transistor. When the luminance level of the display luminance value of the display panel is relatively low, the driving current formed in the pixel circuit according to the data voltage is relatively small. At this time, the first initialization voltage can be adjusted according to the display brightness value, so that the first initialization voltage is relatively large. When the pixel circuit is in the light emitting stage, the voltage difference between the first pole and the second pole of the sixth transistor T6 is relatively small, and the leakage current of the driving current in the pixel circuit through the sixth transistor T6 is relatively small, so that more driving current flows into the light emitting device E1 to drive the light emitting device E1 to emit light, and the leakage current phenomenon in the pixel circuit is reduced. Moreover, the leakage current characteristics of the sixth transistor T6 in different pixel circuits are different, which causes different currents for driving the light emitting device E1 to emit light in different pixel circuits, and by reducing the leakage current of the sixth transistor T6, the current difference for driving the light emitting device E1 to emit light in different pixel circuits can be reduced, and the brightness uniformity of the display panel is improved. When the luminance level of the display luminance value of the display panel is relatively high, the driving current formed in the pixel circuit according to the data voltage is relatively large. At this time, the first initialization voltage may be adjusted to be relatively small according to the display luminance value, so that the anode of the light emitting device E1 may be sufficiently initialized in the initialization stage of the pixel circuit. In addition, in the light emitting stage of the pixel circuit, the driving current ratio in the pixel circuit is large, and the luminance unevenness of the display panel caused by the leakage current of the sixth transistor T6 can be ignored, thereby ensuring the luminance uniformity of the display panel. Table 1 shows a relationship between a first initialization voltage and a display luminance value according to an embodiment of the present invention. Table 1 shows that the smaller the display luminance value, the lower the luminance level of the display luminance value, and the larger the voltage value of the first initialization voltage.
Table 1 relationship between a first initialization voltage and a display brightness value according to an embodiment of the present invention
| |
4095 | 3515 | 2600 | 1921 | 1417 | 1300 | 949 | 633 | 399 | 9 |
| Vref1(V) | -3 | -2.5 | -2.4 | -2.3 | -2.2 | -2.1 | -2.0 | -1.9 | -1.8 | -1.7 |
It should be noted that, in other embodiments, the fourth transistor T4 and the fifth transistor T5 may also be double-gate transistors to reduce the leakage current of the pixel circuit.
And S120, providing a first initialization voltage to the pixel circuit, and initializing a light emitting module in the pixel circuit.
Specifically, as can be seen from fig. 3, the light emitting module of the pixel circuit is a light emitting device E1. After the first initialization voltage is determined according to the display luminance value, the first initialization voltage is supplied to the first initialization signal input terminal VREF1, and the sixth transistor T6 is controlled to be turned on by the first scan signal during the initialization phase of the pixel circuit, and the first initialization voltage initializes the anode of the light emitting device E1.
According to the technical scheme of the embodiment, the first initialization voltage is set according to the display brightness value, when the display brightness value is lower, the first initialization voltage is set to be larger, and the leakage current of the driving current on the sixth transistor can be reduced in the light emitting stage of the pixel circuit, so that the leakage current phenomenon in the pixel circuit can be reduced, the current difference of the driving light emitting device of the pixel circuit, caused by the leakage current characteristic of the transistor, for emitting light is reduced, and the brightness uniformity of the display panel is improved.
Fig. 5 is a flowchart illustrating another driving method of a display panel according to an embodiment of the invention. As shown in fig. 5, the method includes:
s210, dividing a plurality of display brightness value intervals according to the range of the display brightness values, wherein each display brightness value interval corresponds to a brightness level of one display brightness value;
specifically, the range of the display luminance values may be divided into a plurality of display luminance value intervals according to the display requirements of the display panel, and each display luminance value interval is used as a luminance level of a display luminance value and corresponds to a gamma curve.
S220, setting a corresponding first initialization voltage constant according to each brightness level; wherein the first initialization voltage constant increases when the brightness level of the display brightness value decreases;
in particular, the display panel has a limit data voltage that can be supplied. When the pixel circuits within the display panel are P-type transistors, the display panel has the minimum data voltage that can be supplied. When the brightness level of the display brightness value is maximum, the data voltage corresponding to the maximum gray scale in the display panel can be set as the minimum data voltage which can be provided by the display panel, and the data voltages corresponding to different gray scales of the display panel in the maximum brightness level are determined according to the gamma curve characteristics. When the brightness level of the display brightness value is gradually decreased, the data voltage corresponding to the maximum gray scale in the display panel is gradually increased, and the data voltages corresponding to different gray scales in the display panel determined according to the gamma curve characteristics are relatively increased, so that the driving current formed in the pixel circuit is decreased. At this time, a corresponding first initialization voltage constant may be set according to each brightness level, and when the brightness level of the display brightness value decreases, the first initialization voltage constant increases correspondingly, and the first initialization voltage corresponding to the display brightness value in the brightness level changes in the first initialization voltage constants corresponding to two adjacent brightness levels, so that when the display brightness value decreases, the corresponding first initialization voltage increases. When the pixel circuit is in the light-emitting stage, the leakage current phenomenon in the pixel circuit is reduced. Meanwhile, the current difference of the light emitting devices driven by different pixel circuits can be reduced, and the brightness uniformity of the display panel is improved.
S230, determining a first initialization voltage corresponding to each display brightness value according to the first initialization voltage constant and the number of the display brightness values in the brightness level; when the display brightness value is reduced, the first initialization voltage is increased.
Specifically, the smaller the brightness level, the larger the corresponding first initialization voltage constant. After the first initialization voltage constant corresponding to each brightness level is determined, the first initialization voltage corresponding to the maximum display brightness value and the first initialization voltage corresponding to the minimum display brightness value in one brightness level can be determined, and then the first initialization voltage corresponding to different display brightness values in the brightness level can be determined according to the number of display brightness values in the brightness level, an interpolation method and the like.
Illustratively, the first initialization voltage and the display luminance value are linearly related within a luminance level of a display luminance value. At this time, the first initialization voltage constant corresponding to the brightness level may be used as a constant term in the linear relationship, and a proportionality coefficient of the linear relationship is determined according to the number of display brightness values in the brightness level, and then the first initialization voltage corresponding to each display brightness value in the brightness level is determined. For example, referring to table 1, when the luminance level is the maximum, the range of the display luminance values is 3515-. Then at the current brightness level, the linear relationship between the display brightness value and the first initialization voltage is-2.5-1/1160 x, where x is the display brightness value and y is the first initialization voltage.
It should be noted that, in other embodiments, within a luminance level, the first initialization voltage and the display luminance value may also be in a power relationship, and the specific setting thereof may be determined according to the display requirements of the display panel. Further, the relationship between the first initialization voltage and the display luminance value in other luminance levels can be calculated similarly.
S240, providing a first initialization voltage to the pixel circuit to initialize the light emitting module in the pixel circuit.
Fig. 6 is a flowchart illustrating another driving method of a display panel according to an embodiment of the invention. As shown in fig. 6, the method includes:
s310, setting a first initialization voltage according to the display brightness value;
s320, setting the power supply voltage of the pixel circuit according to the first initialization voltage to enable the voltage difference between two ends of the light emitting module of the pixel circuit to be smaller than or equal to a first threshold value.
Specifically, referring to fig. 3, the power supply voltage of the pixel circuit may be a power supply voltage provided at the second power signal input terminal VSS in the pixel circuit for providing a low potential to the cathode of the light emitting device E1, so that the light emitting device E1 emits light under the action of the driving current. In general, the power voltage is a negative value and is less than the first initialization voltage, so that the driving current mostly passes through the light emitting device E1 to drive the light emitting device E1 to emit light. When the brightness level of the display brightness value of the display panel is lower, the first initialization voltage is higher, so that the anode potential of the light-emitting device E1 is higher after the initialization stage, at this time, the power supply voltage is set according to the first initialization voltage, namely, the power supply voltage is adaptively increased, so that the voltage difference between the first initialization voltage and the power supply voltage is smaller than or equal to the first threshold, namely, the voltage difference between two ends of the light-emitting device E1 is smaller than or equal to the first threshold, thereby avoiding the need of higher data voltage when the display panel displays black pictures in the light-emitting stage, and further reducing the probability of incomplete initialization of the data voltage on the basis of ensuring that the display panel can normally display black pictures. Illustratively, table 2 provides a relationship between the first initialization voltage and the power supply voltage according to an embodiment of the present invention. Wherein DBV is a display brightness value, Vref1 is a first initialization voltage, and Vss is a power voltage. As can be seen from table 2, when the display luminance value is relatively large, so that the first initialization voltage value is relatively large, the power supply voltage is adaptively increased. In addition, the power supply voltages corresponding to different display luminance values within the same luminance level may also be determined by interpolation. For example, the power supply voltage and the display luminance value are linearly related within a luminance level of the display luminance value. When the brightness level is the maximum, the range of the display brightness value is 3515-. Then at the current brightness level, the linear relationship between the display brightness value and the power supply voltage is-3-1/580 x, where x is the display brightness value and z is the power supply voltage. Meanwhile, the power supply voltage is generally less than or equal to-2.5V, so that the pixel circuit can ensure the voltage difference between the anode and the cathode of the light-emitting device E1 when the light-emitting device E1 is driven to emit light in the light-emitting phase, thereby ensuring the light-emitting brightness of the light-emitting device E1. Therefore, as the power supply voltage increases with the display luminance value, the power supply voltage increases up to-2.5V. In addition, the relationship between the power supply voltage and the display luminance value in other luminance levels can be calculated similarly.
Table 2 relationship between the first initialization voltage and the power supply voltage provided in the embodiment of the present invention
| |
4095 | 3515 | 2600 | 1921 | 1417 | 1300 | 949 | 633 | 399 | 9 |
| Vref1(V) | -3 | -2.5 | -2.4 | -2.3 | -2.2 | -2.1 | -2.0 | -1.9 | -1.8 | -1.7 |
| Vss(V) | -3.5 | -2.5 | -2.5 | -2.5 | -2.5 | -2.5 | -2.5 | -2.5 | -2.5 | -2.5 |
It should be noted that the first threshold may be set according to the characteristics of the light emitting device E1, and when the light emitting device E1 is a different device, the first threshold may be adjusted according to the characteristics of the light emitting device E1, and may be 0.8V, for example.
S330, providing a first initialization voltage to the pixel circuit to initialize the light emitting module in the pixel circuit.
Fig. 7 is a flowchart illustrating another driving method of a display panel according to an embodiment of the invention. As shown in fig. 7, the method includes:
s410, setting a first initialization voltage according to the display brightness value;
s420, setting a bright state voltage according to the display brightness value; wherein the bright state voltage increases according to a decrease in the display brightness value;
in particular, different brightness levels correspond to different gamma curves. The data voltage corresponding to each gray level in the gamma curve can be determined according to the precision of the gamma curve and the bright-state voltage and the dark-state voltage. The precision of the gamma curve can be the minimum difference of the data voltage determined according to the bright-state voltage, the dark-state voltage and the gamma debugging digit. For example, when the gamma debug bit number is 10 bits, the minimum difference of the data voltage may be determined by dividing the bright-state voltage and the dark-state voltage corresponding to the luminance level equally into 1024 parts, and then determining the data voltage corresponding to each gray scale according to the display luminance value, where the minimum adjustable value of the data voltage corresponding to each gray scale is the minimum difference of the data voltage. When the brightness level of the display brightness value is lower, the bright-state voltage can be increased, so that the difference value between the bright-state voltage and the dark-state voltage is smaller, then the difference value between the bright-state voltage and the dark-state voltage is divided into 1024 parts, the minimum difference value of the data voltage of each part is reduced, and when the data voltage corresponding to each gray scale is determined, the minimum value of the adjustable data voltage is reduced, so that the data voltage corresponding to each gray scale can be adjusted more accurately, the accuracy of the data voltage is improved, and the brightness uniformity of the display panel is improved. Illustratively, table 3 provides a relationship between the bright-state voltage and the dark-state voltage and the display luminance value according to the embodiment of the present invention. Wherein DBV is a display brightness value, VGMP is a dark state voltage, and VGSP is a bright state voltage. As can be seen from table 3, when the display luminance value is gradually decreased, the dark-state voltage remains unchanged, and the bright-state voltage increases with the decrease of the display luminance value, so that the gamma precision is gradually increased, and the precision of the data voltage can be further improved. The brightness uniformity of the display panel is improved under the condition that the driving current provided by the pixel circuit is relatively small.
Table 3 relationship between bright and dark voltages and display brightness values according to embodiments of the present invention
| |
4095 | 3515 | 2600 | 1921 | 1417 | 1300 | 949 | 633 | 399 | 9 |
| VGMP(V) | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 |
| VGSP(V) | 1.5 | 1.7 | 1.9 | 2.1 | 2.3 | 2.5 | 2.7 | 2.9 | 3.1 | 3.5 |
It should be noted that, when the display panel displays at a low brightness level, data voltage within a range of 4V-7V is generally required for displaying, and a margin of 0.5V is left in consideration of the difference of gamma debugging, and at this time, the bright state voltage can be set to 3.5V, so that on the basis of ensuring that the data voltage of the display panel meets the display requirement, the gamma precision is improved as much as possible.
And S430, determining data voltages corresponding to different display brightness values according to the bright-state voltage and the dark-state voltage.
Specifically, after the bright-state voltage is set, the dark-state voltage may be kept unchanged, and then the data voltages corresponding to different gray scales at different display luminance values are determined according to the bright-state voltage and the dark-state voltage, when the pixel circuit operates in the data writing stage, the data voltages are provided to the pixel circuit, and the pixel circuit forms a driving current according to the data voltages to drive the light emitting device to emit light.
S440, providing a first initialization voltage to the pixel circuit to initialize the light emitting module in the pixel circuit.
On the basis of the above technical solutions, when initializing a light emitting module in a pixel circuit, the method further includes:
and providing a second initialization voltage to the pixel circuit to initialize the memory module in the pixel circuit.
Specifically, referring to fig. 3, the storage module in the pixel circuit may be a storage capacitor Cst. The second initialization voltage may be the initialization voltage provided by the second initialization signal input terminal VREF 2. The pixel circuit may further include a fifth transistor T5, and during an initialization phase of the pixel circuit, the first scan signal controls the fifth transistor T5 to be turned on, and the second initialization voltage is transmitted to the storage capacitor Cst through the fifth transistor T5, so that the storage capacitor Cst is initialized.
On the basis of the above technical solutions, after initializing the light emitting module in the pixel circuit, the method further includes:
and providing a data voltage to the pixel circuit, and writing data into the memory module in the pixel circuit.
Specifically, after the initialization phase of the pixel circuit, the pixel circuit enters a data writing phase, the second SCAN signal provided by the second SCAN signal input terminal SCAN2 controls the first transistor T1 and the fourth transistor T4 to be turned on, the data voltage provided by the data voltage input terminal VDATA is written to the gate of the driving transistor Tdr through the first transistor T1, the driving transistor Tdr and the fourth transistor T4, and the data voltage is stored through the storage capacitor Cst, and the writing of the data voltage and the threshold compensation of the driving transistor Tdr are completed.
On the basis of the above technical solutions, after data is written into the memory module in the pixel circuit, the method further includes:
and providing a light-emitting control signal to the pixel circuit to control the light-emitting module in the pixel circuit to emit light.
Specifically, after the data writing phase of the pixel circuit, the pixel circuit enters a light emitting phase, and at this time, the light emitting control signal provided by the light emitting control signal input terminal EM controls the second transistor T2 and the third transistor T3 to be turned on, so that the driving transistor Tdr forms a driving current according to the data voltage and outputs the driving current to the light emitting device E1, and the light emitting device E1 is driven to emit light, thereby realizing the display of the display panel.
The embodiment of the invention also provides a driving device of the display panel. Fig. 8 is a schematic structural diagram of a driving apparatus of a display panel according to an embodiment of the present invention. As shown in fig. 8, the driving apparatus of the display panel includes:
a first initialization voltage setting unit 10 for setting a first initialization voltage according to a display luminance value;
specifically, the first initialization voltage setting unit 10 may be integrated in a driving chip of the display panel, and specifically, setting the first initialization voltage according to the display brightness value may be implemented by setting a 51 register for setting the display brightness value in the driving chip. When the display luminance value is small, the first initialization voltage is set to be high.
The first initialization voltage providing unit 20 is configured to provide a first initialization voltage to the pixel circuit to initialize a light emitting module in the pixel circuit.
Specifically, the first initialization voltage providing unit 20 may be integrated in a driving chip of the display panel, and the driving chip provides the first initialization voltage to the pixel circuit to initialize the light emitting module in the pixel circuit.
According to the technical scheme of the embodiment of the invention, the first initialization voltage is set by the first initialization voltage setting unit according to the display brightness value, when the display brightness value is lower, the first initialization voltage is set to be larger, and the leakage current of the driving current on the sixth transistor can be reduced in the light-emitting stage of the pixel circuit, so that the leakage current phenomenon in the pixel circuit can be reduced, the current difference of the driving light-emitting device of the pixel circuit caused by the leakage current characteristic of the transistor is reduced, and the brightness uniformity of the display panel is improved.
On the basis of the above technical solution, the first initialization voltage setting unit includes:
a display brightness value interval dividing subunit, configured to divide a plurality of display brightness value intervals according to a range of display brightness values, where each display brightness value interval corresponds to a brightness level of a display brightness value;
the first initialization voltage constant setting subunit is used for setting a corresponding first initialization voltage constant according to each brightness grade; wherein the first initialization voltage constant increases when the brightness level of the display brightness value decreases;
the first initialization voltage determining unit is used for determining a first initialization voltage corresponding to each display brightness value according to a first initialization voltage constant and the number of the display brightness values in the brightness level; when the display brightness value is reduced, the first initialization voltage is increased.
Optionally, the first initialization voltage and the display brightness value have a linear relationship within a brightness level of a display brightness value.
In addition to the above technical solutions, the driving device of the display panel may further include:
and the power supply voltage setting unit is used for setting the power supply voltage of the pixel circuit according to the first initialization voltage so that the voltage difference between two ends of the light emitting module of the pixel circuit is smaller than or equal to a first threshold value. Therefore, the requirement of higher data voltage when the display panel displays a black picture in a light-emitting stage can be avoided, and the probability of incomplete initialization of the data voltage can be reduced on the basis of ensuring that the display panel can normally display the black picture.
In addition to the above technical solutions, the driving device of the display panel may further include:
the bright state voltage setting unit is used for setting the bright state voltage according to the display brightness value; wherein the bright state voltage increases according to a decrease in the display brightness value;
and the data voltage determining unit is used for determining the data voltages corresponding to different display brightness values according to the bright-state voltage and the dark-state voltage.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (7)
1. A driving method of a display panel, the display panel including a pixel circuit; characterized in that the method comprises:
setting a first initialization voltage according to the display brightness value;
providing the first initialization voltage to the pixel circuit, and initializing a light emitting module in the pixel circuit;
the setting of the first initialization voltage according to the display brightness value comprises the following steps:
dividing a plurality of display brightness value intervals according to the range of the display brightness values, wherein each display brightness value interval corresponds to the brightness level of one display brightness value;
setting a corresponding first initialization voltage constant according to each brightness grade; wherein the first initialization voltage constant increases as the brightness level of the display brightness value decreases;
determining a first initialization voltage corresponding to each display brightness value according to the first initialization voltage constant and the number of display brightness values in the brightness level; wherein when the display brightness value decreases, the first initialization voltage increases;
within a brightness level of the display brightness value, the first initialization voltage and the display brightness value are in a linear relationship.
2. The method for driving a display panel according to claim 1, further comprising, after setting the first initialization voltage according to a display luminance value:
and setting the power supply voltage of the pixel circuit according to the first initialization voltage to enable the voltage difference between two ends of a light emitting module of the pixel circuit to be smaller than or equal to a first threshold value.
3. The method for driving a display panel according to claim 1, further comprising, after setting the first initialization voltage according to a display luminance value:
setting a bright state voltage according to the display brightness value; wherein the bright state voltage increases in accordance with a decrease in the display brightness value;
and determining data voltages corresponding to different display brightness values according to the bright-state voltage and the dark-state voltage.
4. The method for driving a display panel according to claim 3, further comprising, after initializing a light emitting module in the pixel circuit:
and providing the data voltage to the pixel circuit, and writing data into a storage module in the pixel circuit.
5. The method for driving a display panel according to claim 4, further comprising, after writing data to the memory block in the pixel circuit:
and providing a light-emitting control signal to the pixel circuit to control the light-emitting module in the pixel circuit to emit light.
6. The method for driving a display panel according to claim 1, further comprising, at the time of initializing a light emitting module in the pixel circuit:
and providing a second initialization voltage to the pixel circuit to initialize the storage module in the pixel circuit.
7. A driving apparatus of a display panel including a pixel circuit, the driving apparatus comprising:
a first initialization voltage setting unit for setting a first initialization voltage according to a display brightness value;
a first initialization voltage providing unit, configured to provide the first initialization voltage to the pixel circuit, and initialize a light emitting module in the pixel circuit;
the first initialization voltage setting unit includes:
a display brightness value interval dividing subunit, configured to divide a plurality of display brightness value intervals according to the range of the display brightness values, where each display brightness value interval corresponds to a brightness level of one display brightness value;
the first initialization voltage constant setting subunit is used for setting a corresponding first initialization voltage constant according to each brightness grade; wherein the first initialization voltage constant increases as the brightness level of the display brightness value decreases;
a first initialization voltage determining unit, configured to determine, according to the first initialization voltage constant and the number of display luminance values in the luminance level, a first initialization voltage corresponding to each display luminance value; wherein the first initialization voltage increases when the display brightness value decreases;
within a brightness level of the display brightness value, the first initialization voltage and the display brightness value are in a linear relationship.
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| CN114267299B (en) * | 2021-12-28 | 2023-06-02 | 昆山工研院新型平板显示技术中心有限公司 | Display device and driving method |
| CN114420032B (en) | 2021-12-31 | 2023-09-19 | 湖北长江新型显示产业创新中心有限公司 | Display panel, integrated chip and display device |
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