Pursuant to 35 U.S.C. § 119 and the Paris Convention, this application claims the benefit of Chinese Patent Application No. 202211102368.X filed on Sep. 9, 2022, the content of which is incorporated herein by reference.
The present application relates to the field of display technology, and in particular, to a driving method and a driving circuit for a display panel, and a display device.
The statements provided herein are merely background information related to the present application, and do not necessarily constitute any prior arts. With the rapid development of information technology, people have higher and higher requirements for visual senses. This is also full of challenges and expectations for the display industry with TFT-LCD as the mainstream, to enable consumers to have a better visual experience. Flip (pixel flipping) architecture and the corresponding flipping mode can achieve the effect of dot inversion, resulting in the most uniform panel display. Among them, the display screen with high frequency is also widely used at present, but the charging time of high frequency may be insufficient. BG (water blue) color mixed screens will have charging differences between different rows of pixels, and the charging difference will be more obvious when the charging time is insufficient. Visual differences in brightness, that is, bright and dark lines will occur when the charging of pixels in different rows are different.
The main reason for the difference between brightness and darkness is that, in the two-color mixed color screen, the actual data waveform will be delayed when the polarity is reversed, the data voltage waveform has a climbing ramp when converting from a red pixel to a blue or green pixel. At this time, a charging rate of the blue or green pixel will be lower than that of a pixel which is not converted from the red pixel, resulting in bright and dark lines.
An objective of the present application is to provide a driving method for a display panel, which aims to improve a problem of bright and dark lines in a traditional display panel by increasing a binding-point voltage of a blue pixel or a green pixel.
In accordance with a first aspect of the embodiments of the present application, a driving method for a display panel is provided, the display panel includes a plurality of data lines, a plurality of scan lines and a plurality of pixel groups arranged in an array. Each pixel group includes a red pixel, a green pixel and a blue pixel arranged in sequence along a row direction. Multiple pixels in the same column are sequentially cross-connected to data lines in two adjacent columns, and multiple pixels in the same row are respectively connected to data lines in different columns. A binding-point voltage corresponding to a gray scale of a binding point of the green pixel or the blue pixel is equal to a charging voltage of the red pixel.
The driving method for the display panel includes steps of: detecting the binding-point voltage, and obtaining, through a calculation, a voltage difference between the binding-point voltage and a common-electrode voltage; boosting the binding-point voltage to a preset binding-point voltage in case that the voltage difference between the binding-point voltage and the common-electrode voltage is smaller than a preset voltage difference; and performing a line-by-line scan charging on each row of pixels by using the boosted binding-point voltage, to charge the green pixel or the blue pixel to a charging voltage corresponding to a target gray scale, and to charge the red pixel to the preset binding-point voltage.
Optionally, the binding-point voltage includes a binding-point voltage of positive polarity and a binding-point voltage of negative polarity, and the preset binding-point voltage includes a preset binding-point voltage of positive polarity and a preset binding-point voltage of negative polarity.
The step of boosting the binding-point voltage to a preset binding-point voltage in case that the voltage difference between the binding-point voltage and the common-electrode voltage is smaller than a preset voltage difference specifically includes steps of: boosting the binding-point voltage of positive polarity to the preset binding-point voltage of positive polarity in case that the voltage difference between the binding-point voltage of positive polarity and the common-electrode voltage is smaller than the preset voltage difference; and boosting the binding-point voltage of negative polarity to the preset binding-point voltage of negative polarity in case that the voltage difference between the binding-point voltage of negative polarity and the common-electrode voltage is smaller than the preset voltage difference.
Optionally, the driving method also includes a step of boosting the binding-point voltage to the preset binding-point voltage and increasing a charging time of each pixel to a preset charging time in case that the voltage difference between the binding-point voltage and the common-electrode voltage is smaller than the preset voltage difference.
Optionally, the charging time is equal to a difference between a refresh time and a dead time of each row of pixels.
The step of boosting the binding-point voltage and increasing the charging time of each pixel specifically includes steps of: maintaining the refresh time of each row of pixels unchanged, and increasing the charging time of each pixel to the preset charging time in case that the voltage difference between the binding-point voltage and the common-electrode voltage is smaller than the preset voltage difference; or alternatively, maintaining the dead time of each row of pixels unchanged, and increasing the refresh time of each pixel, to enable the charging time of each pixel to be increased to the preset charging time in case that the voltage difference between the binding-point voltage and the common-electrode voltage is smaller than the preset voltage difference.
Optionally, the driving method also includes a step of invoking data in a preset data mapping table to perform a voltage compensation on a target voltage corresponding to the target gray scale of the green pixel and the blue pixel, and to perform the voltage compensation on the charging voltage of the red pixel.
Optionally, the step of invoking data in the preset data mapping table to perform the voltage compensation on a target voltage corresponding to the target gray scale of the green pixel and the blue pixel, and to perform the voltage compensation on the charging voltage of the red pixel specifically include steps of: obtaining the target voltage corresponding to the target gray scale of the green pixel and the blue pixel of each row to be scanned and the preset binding-point voltage; invoking a compensation voltage mapped with each target voltage and the preset binding point voltage in the preset data mapping table according to the target voltage corresponding to the target gray scale of the green pixel and the blue pixel of each row to be scanned and the preset binding-point voltage; and outputting the compensation voltage to perform the voltage compensation on the target voltage and the preset binding-point voltage of each row of pixels to be scanned.
Optionally, a magnitude of the compensation voltage is in a positive correlation with the target voltage of each row of pixels and the magnitude of the preset binding-point voltage.
Optionally, the driving method also includes a step of inverting the polarity of each of the data lines in a frame inversion mode and/or in a column inversion mode. The frame inversion mode is that a polarity of a data line in one frame and a polarity of the same data line in an adjacent frame are opposite. The column inversion mode is that the polarities of adjacent data lines in the same frame are opposite.
In accordance with a second aspect of the embodiments of the present application, a driving circuit for a display panel is provided, including a source drive circuit, a gate drive circuit, and a timing controller. The timing controller is connected to the source drive circuit and the gate drive circuit respectively. The source drive circuit is connected to data lines of the display panel, and the gate drive circuit is also connected to scan lines of the display panel. The timing controller includes a memory, a processor and a display-panel driver program stored on the memory and executable on the processor, the processor implements the above-mentioned driving method for the display panel when the display panel driver program is executed by the processor.
In accordance with a third aspect of the embodiments of the present application, a display device is provided, including a backlight source, a display panel, and the above-mentioned driving circuit for the display panel. The display panel is correspondingly connected to the driving circuit for the display panel.
Compared with the conventional arts, the embodiments of the present application have the following beneficial effects: in the above driving method for the display panel, the binding-point voltage is detected first and the voltage difference between the binding-point voltage and the common-electrode voltage is calculated. In case that the voltage difference of the electrode voltage is smaller than the preset voltage difference, an existence of the problem of bright and dark lines on the display panel is indicated, a waveform of data voltage has a ramp-up, and the charging rate of the blue pixel or green pixel is insufficient, in this case, the binding-point voltage, i.e., the charging voltage of the red pixel is boosted to reduce a charging loss during a ramp-up process, and to increase the charging rate, thus the bright and dark lines of the display panel can be improved, thereby improving the display effect.
To make the objectives, solutions and beneficial effects of the present application more comprehensible, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that specific embodiments described herein are only used to explain the present application, and are not intended to limit the present application.
In addition, the terms “first” and “second” are used for descriptive purposes only and should not be understood as indicating or implying relative importance or as implicitly indicating the number of features indicated. Thus, a feature defined with “first” and “second” may explicitly or implicitly include one or more such features. In the description of the present application, the phrase “a/the plurality of” means two or more, unless otherwise expressly and specifically limited.
A first aspect of the embodiments of the present application provides a driving method for a display panel 1.
In an embodiment, as shown in
In the water-blue mixed color screen, the charging voltage of the red pixel is equal to the voltage of gamma7 or gamma8, and the liquid crystal does not flip, so that the brightness of the liquid crystal is basically in an opaque state, and the corresponding area of the display panel is displayed as a black picture with the lowest energy consumption, which will not cause any impact on the display screen. After the red pixel R in the previous row is charged from the common-electrode voltage VCOM to a charging voltage L0+ of the red pixel R, that is, to a voltage of gamma7 or gamma8, the green pixel G is charged and boosted on the basis of the charging voltage of the red pixel R until the voltage of the green pixel G is boosted to a target voltage L1+ corresponding to a target gray scale, a switching of high-and-low voltage of the green pixel G and the red pixel R is existed. Or alternatively, for the red pixel R of the first row and the blue pixel B of the second row connected to the fourth data line D4, the blue pixel B is charged and boosted on the basis of the charging voltage of the red pixel R until the voltage of the blue pixel B is boosted to the target voltage L1+ corresponding to the target gray scale, after the red pixel R in the previous row is charged from the common-electrode voltage VCOM to the charging voltage L0+ of the red pixel R, and a switching of high-and-low voltage of the blue pixel B and the red pixel R is existed. While for the blue pixel B and the green pixel G connected to the third data line D3 and the sixth data line D6, since both the blue and green pixels are charged on the basis of the charging voltage of the red pixel R, the voltage difference between the blue pixel and the green pixel has little change. Therefore, no switching between high and low voltages occurs, and the corresponding charging rate of pixel is high, a variation in brightness of the blue and green pixels is not large, which will not cause the problem of brightness and darkness lines. Due to the delay in the actual data waveform when the polarity is reversed, the data voltage waveform has a ramp when converting from the red pixel R to the blue pixel B or green pixel G, and the charging rate of the green pixel G or blue pixel B will be lower than that of the pixel which is not converted from the red pixel R, resulting in a difference in brightness, which then will cause bright and dark lines.
To improve the problem of bright and dark lines, as shown in
In step S10, a binding-point voltage is detected, and a voltage difference between the binding-point voltage and a common-electrode voltage VCOM is calculated.
In step S20, the binding-point voltage is boosted to a preset binding-point voltage in case that the voltage difference between the binding-point voltage and the common-electrode voltage VCOM is smaller than a preset voltage difference.
In step S30: a line-by-line scan charging is performed on each row of pixels by using the boosted binding-point voltage, to charge the green pixel or the blue pixel to a charging voltage corresponding to a target gray scale, and to charge the red pixel to the preset binding-point voltage.
In this embodiment, the binding-point voltage is detected by a voltage detection module, and the common-electrode voltage is obtained directly or through detection, and the voltage difference between the binding-point voltage and the common-electrode voltage is calculated, in this embodiment, when the voltage difference between the binding-point voltage and the common-electrode voltage is smaller than the preset voltage difference, that is, there is a large voltage difference between the binding-point voltage and the charging voltage corresponding to the target gray scale, and a waveform of data voltage has a ramp, at this time, a charging rate of the green pixel G or blue pixel B will be higher than that of the pixel which is not converted from the red pixel, resulting in brightness differences and appearing bright and dark lines. The binding-point voltage output to the display panel 1 is adjusted directly by a drive device, or a corresponding driving circuit 2 is controlled by the drive device to adjust the binding-point voltage output to the display panel 1. As shown in
Meanwhile, the binding-point voltage of each pixel may be equal or different, and the target voltage corresponding to the target gray scale of each pixel may be equal or different, which can be adjusted according to the display requirements during a line driving process.
In this embodiment, the voltage difference refers to an absolute voltage difference, i.e., an absolute value of the difference between the binding-point voltage and the common-electrode voltage VCOM.
Compared with the prior arts, the embodiment of the present application has the following beneficial effect: in the driving method for the display panel 1, the binding-point voltage is detected and the voltage difference between the binding-point voltage and the common-electrode voltage VCOM is calculated. In case that the voltage difference between the binding-point voltage and the common-electrode voltage VCOM is smaller than the preset voltage difference, an existence of the problem of bright and dark lines on the display panel 1 is indicated, the waveform of data voltage has a ramp-up, and the charging rate of the blue pixel B or green pixel G is insufficient, in this case, the binding-point voltage, i.e., the charging voltage of the red pixel R is boosted to reduce the charging loss during a ramp-up process, and to increase the charging rate, thus the bright and dark lines on the display panel 1 can be improved, thereby improving the display effect.
As shown in
The step of boosting the binding-point voltage to the preset binding-point voltage in case that the voltage difference between the binding-point voltage and the common-electrode voltage is smaller than the preset voltage difference specifically includes steps S21 and S22.
In step S21, the binding-point voltage of positive polarity is boosted to the preset binding-point voltage of positive polarity in case that the voltage difference between the binding-point voltage of positive polarity and the common-electrode voltage VCOM is smaller than the preset voltage difference.
In step S22, the binding-point voltage of negative polarity is boosted to the preset binding-point voltage of negative polarity in case that the voltage difference between the binding-point voltage of negative polarity and the common-electrode voltage VCOM is smaller than the preset voltage difference.
In this embodiment, corresponding to different driving modes of a dot inversion of the display panel 1, the binding-point voltage has a corresponding positive or negative polarity. The positive polarity refers to that the binding-point voltage is greater than the common-electrode voltage VCOM, and the negative polarity refers to that the binding-point voltage is lower than the common-electrode voltage VCOM.
It can be understood that an average value of the binding-point voltage of positive polarity and the binding-point voltage of negative polarity is equal to the common-electrode voltage. Therefore, after the magnitude of one binding-point voltage is obtained, the magnitude of the other binding-point voltage of opposite polarity, as well as the voltage difference between the other binding-point voltage of opposite polarity and the common-electrode voltage can be obtained.
The binding-point voltage of positive polarity and/or the binding-point voltage of negative polarity are obtained through a detection. In case that the voltage difference between the binding-point voltage of positive or negative polarity and the common-electrode voltage is detected to be smaller than the preset voltage difference, indicating that the data signal has a ramp-up, and the problem of bright and dark lines is existed, the binding-point voltage of positive polarity and the binding-point voltage of negative polarity are boosted simultaneously, as shown in
For example, as shown in
Or alternatively, with regard to the red pixel R and the blue pixel B arranged diagonally in two adjacent rows on the third data line D4, when it is detected that the voltage difference between the binding-point voltage of positive or negative polarity and the common-electrode voltage VCOM is smaller than the preset voltage difference, the binding-point voltage of negative polarity of the blue pixel B in the third column and the second row is boosted from the binding-point voltage L0− to the preset binding-point voltage of negative polarity L01−, that is, the charging voltage of the positive polarity of the red pixel R in the fourth column and the first row is boosted from L0− to L01−, which increases the charging rate and improves bright and dark lines.
As shown in
In this embodiment, when it is detected that the voltage difference between the binding-point voltage of positive or negative polarity and the common-electrode voltage is smaller than the preset voltage difference, indicating that the data signal has a ramp-up, and the problem of bright and dark lines is existed, the binding-point voltage of the green pixel G or blue pixel B is boosted in one aspect, and the charging time of each pixel is increased in another aspect, so that the overall charging time is increased, the brightness of pixels will become brighter, in this way, a gap between brightness and darkness will be smaller, and after all pixels become brighter, the difference between brightness and darkness is non-obvious.
As shown in
In this embodiment, to prevent the simultaneous charging of two adjacent rows, resulting in abnormal display, a refresh time of line scan includes the charging time of pixel and an error-proof charging time (i.e., a dead time). Optionally, the charging time is equal to a difference between the refresh time and the dead time of each row of pixels.
For example, take FHD 165 Hz display panel 1 (resolution: 1080*1920) as an example: the refresh time of one line scan is 5.46 us, the line scan time is equal to a sum of the charging time and the dead time, and a range of the dead time is set at 1˜1.3 us, in this case, the charging time is 4.16˜4.46 us. An increasing of the overall charging time can improve the brightness of the pixels during the ramp-up of the charging voltage of the data line and reduce the brightness difference.
Corresponding to a relationship between the refresh time and the charging time, the steps of boosting the binding-point voltage and increasing the charging time of each pixel in case that the voltage difference between the binding-point voltage and the common-electrode voltage is smaller than the preset voltage difference specifically include steps of:
In this embodiment, as shown in
As shown in
In a case that the refresh time remains unchanged, with regard to the red pixel R, before refreshing to the green pixel G or blue pixel B in the next row, the red pixel R, by increasing the charging time t11 and reducing the dead time t12, can reliably rise to the boosted charging voltage, which can ensure that the binding-point voltage of the blue pixel B or green pixel G is raised to the boosted binding-point voltage before charging itself. Meanwhile, with regard to the blue pixel B or green pixel G, it can be guaranteed that the blue pixel B or green pixel G, by increasing the charging time t21 and reducing the dead time t22, can be reliably charged to the target voltage corresponding to the target gray scale based on the binding-point voltage, which increases the charging rate.
Or alternatively, as shown in
As shown in
In step S60, a voltage compensation is performed on the target voltage corresponding to the target gray scale of the green pixel G and the blue pixel B, and on the charging voltage of the red pixel R by invoking data in a preset data mapping table.
As shown in
Or alternatively, as shown in
In a further aspect, the charging voltage of the red pixel R, i.e., the voltage of gamma7 or gamma8, and the target voltage of the green pixel G and blue pixel B are compensated in an overdrive mode, to further ensure that the charging voltage of the red pixel R, the target voltage of the green pixel G and blue pixel B reaches the preset voltage. As shown in
As shown in
In step S61, the target voltage corresponding to the target gray scale of the green pixel G and the blue pixel B in each row to be scanned and the preset binding-point voltage are obtained.
In step S62, a compensation voltage that is mapped with each target voltage and the preset binding-point voltage in the preset data mapping table is invoked according to the target voltage corresponding to the target gray scale of the green pixel G and the blue pixel B of each row to be scanned and the preset binding-point voltage.
In step S63, the compensation voltage is output to perform the voltage compensation on the target voltage and the preset binding-point voltage of each row of pixels to be scanned.
In this embodiment, since the final target voltages of blue pixel B and green pixel G may be the same or different, different compensation voltages are set according to the preset binding-point voltage and target voltage required by each pixel, that is, in the line driving process, the data in the preset data mapping table is correspondingly invoked to compensate the target voltage and the preset binding-point voltage of each pixel to further ensure that the blue pixel B or green pixel G is reliably charged to the required target charging voltage on the basis of the binding-point voltage, thereby increasing the charging rate and improving bright and dark lines.
In this embodiment, the binding-point voltage of each green pixel G or blue pixel B and the binding-point voltage corresponding to the target voltage, that may lead to a switching of high-and-low voltage, are pre-stored in the preset data mapping table, and a mapping relationship is formed the two. When a polarity reversal occurs in one row is identified, the compensation voltage on each data line of the corresponding row is invoked to perform a voltage compensation respectively when the switching of high-and-low voltage occurs, thereby improving the efficiency of voltage compensation.
In this embodiment, as shown in
Optionally, as shown in
In this embodiment, the frame inversion mode is that: a polarity of a data line in one frame and a polarity of the same data line in an adjacent frame are opposite;
The column inversion mode is that: the polarities of adjacent data lines in the same frame are opposite.
In this embodiment, referring to
And/or, the polarity inversion is performed in different frames, that is, for the same data line, the polarity inversion is performed in adjacent frames, and for each pixel, the dot inversion is realized in the previous frame and the next frame, so that the power consumption can be reduced, and the function of wide viewing angle is realized which then can optimize the display effect.
A second aspect of the embodiments of the present application provides a driving circuit 2 for a display panel, as shown in
In this embodiment, the timing controller 30, as an execution subject, is configured to control operations of the source drive circuit 20 and the gate drive circuit 10 respectively during a normal driving. That is, control signals are output by the timing controller 30 to the source drive circuit 20 and the gate drive circuit 10 respectively. The control signal includes a start signal, a clock signal, a polarity inversion control signal, an enable signal, etc. The gate drive circuit 10 outputs a line scan signal to the scan line according to the control signal to achieve a line-by-line scan, including a forward scan or a reverse scan. Meanwhile, the source driver circuit 20 outputs a corresponding charging voltage to the pixels of each row according to the control signal when the pixels of each row are switched on, so that the pixels in each row are switched on to emit light.
In the meantime, the magnitude of the binding-point voltage is detected by the timing controller 30 through a built-in voltage detection circuit or an additional voltage detection circuit to determine a display state of the display panel 1, and the magnitude of an output voltage of the source driver circuit 20 or the gamma circuit, and the charging time of each pixel is adjusted accordingly by the timing controller 30, to implement a charging adjustment of each pixel, including adjustments to the corresponding binding-point voltage, target charging voltage, charging time, voltage compensation and other adjustments.
In this embodiment, the timing controller 30 carries out data debugging before the display panel 1 formally displays a screen or before leaving the factory. It is ensured, by obtaining the required binding-point voltage and target voltage of each row of pixels, the refresh time of the line scan, and the required compensation voltage, and adjusting correspondingly the binding-point voltage, the target voltage, the charging time of line scan, and the required compensation voltage, that the blue pixel B or green pixel G can be reliably charged to the target voltage corresponding to the target gray scale on the basis of the binding-point voltage, which increases the charging rate, and improves bright and dark lines.
A third aspect of the embodiments of the present application further provides a display device. As shown in
In this embodiment, the driving circuit 2 for the display panel scans and lights up the display panel 1 line by line to realize the normal driving, and cooperates with the backlight source 3 to display corresponding image information.
Here, a plurality of pixels in the same column of the display panel 1 are sequentially cross-connected to data lines in two adjacent columns, and a plurality of pixels in the same row are respectively connected to data lines in different columns, and pixels in each row are respectively connected to the same scan line. The scan line may be a single line arranged between pixels in adjacent rows or may be double lines arranged between pixels in adjacent rows, the arrangement of data lines will not be limited in here, and pixels in the same column are pixels of the same type.
The above-mentioned are merely some optional embodiments of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that the solutions described in the foregoing embodiments may still be modified, or some of the features may be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding solutions deviate from the spirit and scope of the solutions of the various embodiments of the application, and should all be included within the protection scope of the present application.
Number | Date | Country | Kind |
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202211102368.X | Sep 2022 | CN | national |