Field sequence display circuit and brightness compensation method

Abstract

The invention discloses a field order display circuit and a brightness compensation method. The method comprises the following steps: acquiring a gray scale picture of a target gray scale; obtaining a brightness difference and a coordinate of a pixel abnormal point based on the gray scale picture; obtaining a to-be-compensated pixel voltage based on the brightness difference and a gamma curve; and performing brightness compensation on the pixel abnormal point based on the pixel abnormal point coordinate, the to-be-compensated pixel voltage and the pixel voltage corresponding to the target gray scale. The field sequential display circuit has the beneficial effects that when the field sequential display circuit is put into use, brightness abnormity of some pixel points of a panel picture is found, so that brightness compensation is carried out according to coordinates and brightness differences of the pixel abnormal points, the uniformity of the panel picture is better, stable picture brightness is obtained, and a high-quality and stable picture is obtained.

Description

Technical Field

[0001] The present invention relates to the field of pixel display technology, and in particular to a field sequential display circuit and a brightness compensation method. Background Art

[0002] In the prior art, according to the principle of charge conservation, the charge of the pixel capacitor after the liquid crystal is deflected is the same as the charge of the pixel capacitor at the moment the data signal voltage is written to the pixel capacitor. The data signal voltage is generated based on the pixel capacitor before the liquid crystal is deflected, the holding capacitor, the current pixel voltage, the common voltage and the charge of the pixel capacitor, thereby solving the problem of inaccurate grayscale voltage in traditional pixel driving circuits.

[0003] However, in actual applications, it is found that the brightness of the panel display is uneven across the entire surface. The unevenness comes from the differences in the characteristics of the pixel light emission. Therefore, the pixels with different light emission are called pixel anomalies. The brightness of the pixel anomaly is too dark or too bright compared to the surrounding brightness, which makes the picture unstable.

[0004] Therefore, the present invention proposes a field sequential display circuit and a brightness compensation method to further stabilize the screen brightness and optimize the display. Summary of the Invention

[0005] The purpose of the present invention is to provide a field sequential display circuit and a brightness compensation method, which realizes brightness compensation for abnormal pixel brightness, stabilizes the picture brightness, and optimizes the display.

[0006] The present invention aims to implement a field sequential display brightness compensation method through the following technical solutions, including: Get the grayscale image of the target grayscale; Obtain the brightness difference and coordinates of pixel outliers based on the grayscale image; Obtaining a pixel voltage to be compensated based on the brightness difference and the gamma curve; Brightness compensation is performed on the abnormal pixel point based on the coordinates of the abnormal pixel point, the pixel voltage to be compensated, and the target grayscale.

[0007] Furthermore, obtaining a grayscale image of a target grayscale includes: Input the data signal voltage corresponding to the target grayscale to light up the field sequential display circuit / panel; Use a calibrated high-magnification camera to capture: grayscale images of the light emitted from the field sequential display circuit / panel through the imaging component; The correction includes flat field correction, black level correction and linearity correction.

[0008] Furthermore, obtaining the pixel voltage to be compensated based on the brightness difference and the gamma curve includes: A gamma curve is constructed based on the relationship between pixel voltage and brightness corresponding to different grayscales. The gamma curve is: ; Where L is the brightness and V is the pixel voltage; Calculating the pixel voltage to be compensated based on the brightness difference and the gamma curve; ; in, is the brightness difference, is the pixel voltage to be compensated.

[0009] Furthermore, the brightness compensation for the pixel abnormal point based on the pixel abnormal point coordinates, the pixel voltage to be compensated and the target grayscale includes: Construct voltage formula based on the principle of charge conservation; Obtaining a compensation formula based on the pixel voltage to be compensated and the voltage formula; Obtaining a corresponding pixel voltage based on a target grayscale and a gamma curve; Obtaining a compensated data signal voltage based on a corresponding pixel voltage and a compensation formula; Brightness compensation is performed on the abnormal pixel point according to the coordinates of the abnormal pixel point and the compensation data signal voltage.

[0010] The voltage formula constructed based on the charge conservation principle includes: When the field sequential display circuit includes a reset unit, the voltage formula is configured as: ; in, is the data signal voltage of the Nth frame; is the pixel voltage of the Nth frame; is the coupling voltage; A is the first weight coefficient of the pixel voltage, B is the weight coefficient of the coupling voltage, and D is a constant; A compensation formula is obtained based on the pixel voltage to be compensated and the voltage formula, and the compensation formula is configured as: ; in, is the pixel voltage to be compensated, is the compensated data signal voltage of the Nth frame.

[0011] Furthermore, the voltage formula constructed based on the charge conservation principle also includes: When the field sequential display circuit does not include a reset unit, the voltage formula is configured as follows: ; in, is the data signal voltage of the Nth frame; is the pixel voltage of the N+1th frame; is the Nth pixel voltage; is the coupling voltage; A is the first weight coefficient of the pixel voltage, B is the weight coefficient of the coupling voltage, C is the second weight coefficient of the pixel voltage, and D is a constant; A compensation formula is obtained based on the pixel voltage to be compensated and the voltage formula, and the compensation formula is configured as: ; in, is the pixel voltage to be compensated, is the compensated data signal voltage of the Nth frame.

[0012] The present invention also provides a field sequential display circuit, characterized in that the field sequential display circuit includes: a pre-writing unit, a driving unit and a reset unit; The pre-writing unit includes: a first transistor and a pre-storage capacitor; The driving unit includes: a second transistor, a holding capacitor and a pixel capacitor; A first source and drain of the first transistor is coupled to a data signal line, a gate of the first transistor is coupled to a row gate signal line, a second source and drain of the first transistor is coupled to one end of a pre-storage capacitor, and the other end of the pre-storage capacitor is coupled to a common signal line; A first source and drain of the first transistor is coupled to a first source and drain of a second transistor, a gate of the second transistor is coupled to a transfer signal line, a second source and drain of the second transistor is coupled to one end of a pixel capacitor and a holding capacitor, and the other ends of the pixel capacitor and the holding capacitor are both coupled to a common signal line; The reset unit includes a third transistor, a gate of the third transistor is coupled to the reset signal line, a first source and drain of the third transistor is coupled to the second source and drain of the second transistor, and a second source and drain of the third transistor is coupled to the reference signal line.

[0013] The present invention also provides a field sequential display circuit, comprising: a pre-writing unit and a driving unit; The pre-writing unit includes: a first transistor and a pre-storage capacitor; The driving unit includes: a second transistor, a holding capacitor and a pixel capacitor; A first source and drain of the first transistor is coupled to a data signal line, a gate of the first transistor is coupled to a row gate signal line, a second source and drain of the first transistor is coupled to one end of a pre-storage capacitor, and the other end of the pre-storage capacitor is coupled to a common signal line; The first source and drain of the first transistor are coupled to the first source and drain of the second transistor, the gate of the second transistor is coupled to the transfer signal line, the second source and drain of the second transistor are coupled to one end of the pixel capacitor and the holding capacitor, and the other ends of the pixel capacitor and the holding capacitor are coupled to the common signal line.

[0014] Furthermore, in the data writing stage of the field sequential display circuit, the level of the row gate signal line jumps to a high potential, the first transistor is turned on, and the data signal voltage is written into the pre-storage capacitor, and then the level of the row gate signal line jumps back to a low potential, and enters the charge transfer stage, the level of the transfer signal line jumps to a high potential, the second transistor is turned on, and the data signal voltage is transferred to the pixel electrode, and then the transfer signal line jumps back to a low potential.

[0015] The present invention has the following advantages: After the panel is manufactured, it is found that some pixels on the display screen are too dark or too bright during actual use. For these abnormal pixel points, the present invention obtains grayscale photos by taking pictures, obtains the coordinates and brightness difference of the abnormal pixel points from the grayscale photos, and obtains the pixel voltage to be compensated based on the gamma curve; and calculates the compensation data signal voltage based on the charge conservation principle, the pixel voltage to be compensated, and the pixel voltage corresponding to the target grayscale. The compensation data signal voltage and the coordinates of the pixel abnormal point are used to perform brightness compensation through Tcon, so that the brightness of the pixel abnormal point is displayed normally, thereby obtaining a uniform display screen on the panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A diagram showing the steps of the method of the present invention; Figure 2 The circuit of the present invention Figure 1 ; Figure 3 The circuit of the present invention Figure 2 ; Figure 4 This is a timing diagram of the present invention. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0018] It should be noted that the directions or positional relationships indicated by “left”, “right”, etc. are based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the invented product is usually placed when in use, or are the directions or positional relationships commonly understood by those skilled in the art. Such terms are only used to facilitate the description of the present invention and simplify the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0019] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features and technical solutions therein may be combined with each other. Example

[0020] See Figure 1 The present invention provides a method for field sequential display brightness compensation. S1, obtaining a grayscale image of the target grayscale; S11, inputting the data signal voltage corresponding to the target grayscale to light up the field sequential display circuit / panel; S12, using a calibrated high-magnification camera to capture a grayscale image of the light emitted from the field sequential display circuit / panel and displayed by an imaging component; the imaging component includes a projection display component; The correction includes flat field correction, black level correction and linear correction. For high magnification cameras, the unevenness caused by the camera can be removed after correction; flat field correction can remove cloud spots in non-field sequential display images; black level correction can reduce the influence of dark current of the camera sensor; linear correction can accurately restore the brightness of the panel; A high-magnification and high-precision industrial camera is used to capture the image displayed on the panel circuit to obtain a grayscale image. The color distribution characteristics of the pixel points are analyzed based on the collected data from the grayscale image. The gamma index value of each pixel can be calculated, thereby preparing for the subsequent construction of the gamma curve and analysis to obtain pixel anomaly information.

[0021] S2, obtaining the brightness difference and coordinates of pixel outliers based on the grayscale image; By analyzing the local statistical characteristics (such as mean, standard deviation, median, etc.) of each pixel in the grayscale image, we detect pixel anomalies that have significant brightness differences such as being too bright or too dark compared to the surrounding area, and record their coordinates and brightness difference.

[0022] S3, obtaining a pixel voltage to be compensated based on the brightness difference and the gamma curve; S31. Construct a gamma curve based on the relationship between pixel voltage and brightness corresponding to different grayscales. The gamma curve is: ; Where L is the brightness and V is the pixel voltage; S32, calculating the pixel voltage to be compensated based on the brightness difference and the gamma curve; ; in, is the brightness difference, is the pixel voltage to be compensated.

[0023] S4, performing brightness compensation on the abnormal pixel point based on the coordinates of the abnormal pixel point, the pixel voltage to be compensated, and the pixel voltage corresponding to the target grayscale; S41. Construct voltage equation based on the principle of charge conservation; ; Wherein, F=0 means that the field sequential display circuit includes a reset unit; F=1 means that the field sequential display circuit does not include a reset unit; is the data signal voltage of the Nth frame; is the pixel voltage corresponding to the target grayscale of the N+1th frame; is the pixel voltage corresponding to the target grayscale of the Nth frame; is the coupling voltage; A is a first weight coefficient of the pixel voltage, B is a weight coefficient of the coupling voltage, C is a second weight coefficient of the pixel voltage, and D is a constant.

[0024] S42, obtaining a compensation formula based on the pixel voltage to be compensated and the voltage formula; When F=0, the compensation formula is configured as: ; When F=1, the compensation formula is configured as: ; in, is the pixel voltage to be compensated, is the compensated data signal voltage of the Nth frame.

[0025] S43, obtaining a corresponding pixel voltage based on the target grayscale and the gamma curve; S44, obtaining a compensated data signal voltage based on the corresponding pixel voltage and a compensation formula; S45 , performing brightness compensation on the abnormal pixel point according to the abnormal pixel point coordinates and the compensation data signal voltage.

[0026] At this time, the voltage equation in Tcon is adapted to the actual use of the current field sequential display circuit based on the recalculated compensation data signal voltage. The data signal voltage is accurately written to the exact abnormal pixel point according to the coordinates of the pixel abnormal point, so that the brightness of the pixel abnormal point is consistent with the surrounding points, thereby improving the uniformity of the picture. The present invention addresses the problem that pixel abnormalities with display brightness exist in a field sequential display circuit, which causes different screen brightnesses to be obtained with the same data signal voltage, resulting in unstable display screen brightness. The coordinate position and brightness difference of the pixel abnormality are obtained through a grayscale image, and the voltage difference is obtained based on the one-to-one correspondence between brightness and voltage in a gamma curve. The voltage difference can be used to obtain a data signal to be compensated through a compensation formula, and the compensated data signal voltage is accurately transmitted to the pixel abnormality according to the coordinates of the pixel abnormality, so that the pixel abnormality is no longer too dark or too bright, thereby improving the uniformity of the panel display screen. Example

[0027] like Figure 2 As shown, the field sequential display circuit includes: a pre-writing unit, a driving unit and a reset unit, and is applicable to a field sequential display brightness compensation method; The pre-writing unit includes: a first transistor T1 and a pre-storage capacitor Cs1; The driving unit includes: a second transistor T2, a holding capacitor Cs2 and a pixel capacitor Clc; A first source and drain of the first transistor T1 is coupled to the data signal line Data, a gate of the first transistor T1 is coupled to the row gate signal line ScaN, a second source and drain of the first transistor T1 is coupled to one end of the pre-storage capacitor Cs1, and the other end of the pre-storage capacitor Cs1 is coupled to the common signal line Com; A first source and drain of the first transistor T1 is coupled to a first source and drain of the second transistor T2, a gate of the second transistor T2 is coupled to a transfer signal line TraN, a second source and drain of the second transistor T2 is coupled to one end of a pixel capacitor Clc and a holding capacitor Cs2, and the other ends of the pixel capacitor Clc and the holding capacitor Cs2 are coupled to a common signal line Com; The reset unit includes a third transistor T3 , a gate of the third transistor T3 coupled to the reset signal line Reset, a first source and drain of the third transistor T3 coupled to the second source and drain of the second transistor T2 , and a second source and drain of the third transistor T3 coupled to the reference signal line Vref. Example

[0028] like Figure 3 As shown, the field sequential display circuit includes: a pre-writing unit and a driving unit, which is applicable to a field sequential display brightness compensation method; The pre-writing unit includes: a first transistor T1 and a pre-storage capacitor Cs1; The driving unit includes: a second transistor T2, a holding capacitor Cs2 and a pixel capacitor Clc; A first source and drain of the first transistor T1 is coupled to the data signal line Data, a gate of the first transistor T1 is coupled to the row gate signal line ScaN, a second source and drain of the first transistor T1 is coupled to one end of the pre-storage capacitor Cs1, and the other end of the pre-storage capacitor Cs1 is coupled to the common signal line Com; The first source and drain of the first transistor T1 are coupled to the first source and drain of the second transistor T2, the gate of the second transistor T2 is coupled to the transfer signal line TraN, the second source and drain of the second transistor T2 are coupled to one end of the pixel capacitor Clc and the holding capacitor Cs2, and the other ends of the pixel capacitor Clc and the holding capacitor Cs2 are both coupled to the common signal line Com.

[0029] like Figure 4 As shown, in the data writing phase of the Nth frame of the field sequential display circuit, the level of the row gate signal line ScaN jumps to a high potential, the first transistor T1 is turned on, and after the data signal voltage is written into the pre-storage capacitor Cs1, the level of the row gate signal line ScaN jumps back to a low potential and enters the charge transfer phase. The level of the transfer signal line TraN jumps to a high potential, the second transistor T2 is turned on, and after the data signal voltage is transferred to the pixel electrode Clc, the transfer signal line TraN jumps back to a low potential, and the common signal line Com continues to output an AC signal.

[0030] The 2T non-reset field sequence circuit affects the stable value of the pixel voltage in the current frame because the charge of the previous frame will remain. As a result, the voltage of some pixels will be affected, resulting in different screen brightness, causing some points to be too dark or too bright. Therefore, when using the circuit, the coordinates and brightness values of the pixel abnormality points are obtained according to the grayscale image, and the corresponding pixel voltage is obtained according to the gamma curve. The data signal voltage is compensated based on the voltage equation and the target grayscale corresponding pixel voltage for formal use in subsequent circuits, so as to improve the accuracy of the written pixel voltage and the stability of the pixel voltage, so as to obtain a stable test screen brightness. Example

[0031] For using Figure 3 In the panel prepared with the field sequential display circuit shown in the figure, the panel is prepared with N rows of field sequential display circuits. From the first row to the last row of the panel, the display brightness is uneven due to different leakage times; The panel can be divided into rows and partitions. Based on the brightness difference and corresponding voltage difference of the first row, a multi-row compensation formula is constructed to perform voltage compensation on the field sequential display circuit of the nth row, thereby compensating the multi-row field sequential display circuit; The compensation formula for multiple rows is configured as: ; ; ; ; .......; ; ; This embodiment is used to solve the color shift problem in a 2T field sequential display circuit by adopting a row-by-row correction method; the written value of the data signal voltage of each row is corrected by the field sequential display brightness compensation method.

[0032] The above embodiments merely represent preferred implementations, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art will be able to make various modifications and improvements without departing from the present invention, and these modifications and improvements are all within the scope of protection of the present invention.

Claims

1. A field sequential display brightness compensation method, characterized in that: include: Get the grayscale image of the target grayscale; Obtain the brightness difference and coordinates of pixel outliers based on the grayscale image; Obtaining a pixel voltage to be compensated based on the brightness difference and the gamma curve; Brightness compensation is performed on the abnormal pixel point based on the coordinates of the abnormal pixel point, the pixel voltage to be compensated, and the target grayscale.

2. The field sequential display brightness compensation method according to claim 1, characterized in that: The grayscale image of the target grayscale is obtained by: Input the data signal voltage corresponding to the target grayscale to light up the field sequential display circuit / panel; Use a calibrated high-magnification camera to capture: grayscale images of the light emitted from the field sequential display circuit / panel displayed by the imaging component.

3. The field sequential display brightness compensation method according to claim 1, characterized in that: Obtaining the pixel voltage to be compensated based on the brightness difference and the gamma curve includes: A gamma curve is constructed based on the relationship between pixel voltage and brightness corresponding to different grayscales. The gamma curve is: L=V 2.2 ; Where L is the brightness and V is the pixel voltage.

4. The field sequential display brightness compensation method according to claim 1, wherein: The brightness compensation of the pixel abnormal point based on the coordinates of the pixel abnormal point, the pixel voltage to be compensated and the target grayscale includes: Construct voltage formula based on the principle of charge conservation; Obtaining a compensation formula based on the pixel voltage to be compensated and the voltage formula; Obtaining the corresponding pixel voltage based on the target grayscale and gamma curve; Obtaining a compensated data signal voltage based on a corresponding pixel voltage and a compensation formula; Brightness compensation is performed on the abnormal pixel point according to the coordinates of the abnormal pixel point and the compensation data signal voltage.

5. The field sequential display brightness compensation method according to claim 4, characterized in that: The voltage formula constructed based on the charge conservation principle includes: When the field sequential display circuit includes a reset unit, the voltage formula is configured as: V data(n) =V n *A-V0*B+D; in, V data(n) is the data signal voltage of the Nth frame; V n is the pixel voltage corresponding to the target grayscale of the Nth frame; V o is the coupling voltage; A is the first weight coefficient of the pixel voltage, B is the weight coefficient of the coupling voltage, and D is a constant.

6. The field sequential display brightness compensation method according to claim 5, characterized in that: The compensation formula is obtained based on the pixel voltage to be compensated and the voltage formula, and the compensation formula is configured as: V 1data(n) =(V n +ΔV)*A-V0*B+D; Where ΔV is the pixel voltage to be compensated, V 1data(n) is the compensated data signal voltage of the Nth frame.

7. The field sequential display brightness compensation method according to claim 4, characterized in that: The voltage formula constructed based on the charge conservation principle also includes: When the field sequential display circuit does not include a reset unit, the voltage formula is configured as follows: V data(n) =V n+1 *A+V0*BV n *C+D; in, V data(n) is the data signal voltage of the Nth frame; V n+1 is the pixel voltage corresponding to the target grayscale of the N+1th frame; V n is the pixel voltage corresponding to the target grayscale of the Nth frame; V o is the coupling voltage; A is the first weight coefficient of the pixel voltage, B is the weight coefficient of the coupling voltage, C is the second weight coefficient of the pixel voltage, and D is a constant; 8. The field sequential display brightness compensation method according to claim 7, characterized in that: The compensation formula is obtained based on the pixel voltage to be compensated and the voltage formula, and the compensation formula is configured as: V 1data(n) =(V n+1 -ΔV)*A+V0*B-(V n +ΔV)*C+D; Where ΔV is the pixel voltage to be compensated, V 1data(n) is the compensated data signal voltage of the Nth frame.

9. A field sequential display circuit, applicable to the field sequential display brightness correction method according to any one of claims 1 to 6, characterized in that: The field sequential display circuit includes: a pre-writing unit, a driving unit and a reset unit; The pre-writing unit includes: a first transistor (T1) and a pre-storage capacitor (Cs1); The driving unit includes: a second transistor (T2), a holding capacitor (Cs2) and a pixel capacitor (Clc); A first source and drain of the first transistor (T1) is coupled to a data signal line (Data), a gate of the first transistor (T1) is coupled to a row gate signal line (Scan), a second source and drain of the first transistor (T1) is coupled to one end of a pre-storage capacitor (Cs1), and the other end of the pre-storage capacitor (Cs1) is coupled to a common signal line (Com); The first source and drain of the first transistor (T1) are coupled to the first source and drain of the second transistor (T2), the gate of the second transistor (T2) is coupled to a transfer signal line (Tran), the second source and drain of the second transistor (T2) are coupled to one end of a pixel capacitor (Clc) and a holding capacitor (Cs2), and the other ends of the pixel capacitor (Clc) and the holding capacitor (Cs2) are both coupled to a common signal line (Com); The reset unit includes a third transistor (T3), a gate of the third transistor (T3) is coupled to a reset signal line (Reset), a first source and drain of the third transistor (T3) is coupled to a second source and drain of the second transistor (T2), and a second source and drain of the third transistor (T3) is coupled to a reference signal line (Vref).

10. A field sequential display circuit, applicable to the field sequential display brightness correction method according to any one of claims 1 to 4, 7 to 8, characterized in that: The field sequential display circuit includes: a pre-writing unit and a driving unit; The pre-writing unit includes: a first transistor (T1) and a pre-storage capacitor (Cs1); The driving unit includes: a second transistor (T2), a holding capacitor (Cs2) and a pixel capacitor (Clc); A first source and drain of the first transistor (T1) is coupled to a data signal line (Data), a gate of the first transistor (T1) is coupled to a row gate signal line (Scan), a second source and drain of the first transistor (T1) is coupled to one end of a pre-storage capacitor (Cs1), and the other end of the pre-storage capacitor (Cs1) is coupled to a common signal line (Com); A first source and drain of the first transistor (T1) is coupled to a first source and drain of a second transistor (T2), a gate of the second transistor (T2) is coupled to a transfer signal line (Tran), a second source and drain of the second transistor (T2) is coupled to one end of a pixel capacitor (Clc) and a holding capacitor (Cs2), and the other ends of the pixel capacitor (Clc) and the holding capacitor (Cs2) are both coupled to a common signal line (Com).

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