OLED display panel sub-pixel level color equalization compensation method and system based on De-Mura compensation technology

Abstract

The invention provides an OLED (Organic Light Emitting Diode) display panel sub-pixel level color equalization compensation method and system based on a De-Mura compensation technology. The method mainly comprises the steps that a brightness industrial camera shoots brightness data of different gray scales of the OLED display panel for the first time, a brightness uniformity preprocessing process is synchronously carried out, compensation parameters are burnt into a DDIC (Double Data Integrated Circuit), whether chromaticity uniformity compensation needs to be carried out or not is selected according to the chromaticity uniformity expression after brightness uniformity compensation, and if chromaticity uniformity compensation needs to be carried out, the brightness uniformity compensation is carried out. If yes, a shot gray scale picture is determined according to the color expression condition of the OLED panel, the chroma industrial camera shoots different gray scale and chroma data of the OLED display panel for the second time, chroma data processing is carried out to obtain a compensation coefficient, the compensation coefficient acts on brightness compensation data, and therefore brightness and chroma uniformity compensation parameters are obtained; and realizing the brightness and chromaticity compensation of the OLED display panel based on the compensation parameters.

Description

Technical Field

[0001] The present invention relates to an image compensation algorithm, belongs to the field of image processing, and particularly relates to a sub-pixel color balance compensation method and system for an OLED display panel based on De-Mura compensation technology. Background Art

[0002] In today's flat panel display technology field, especially with the continuous overcoming of technical difficulties related to OLED (Organic Light-Emitting Diode) panels and the continuous improvement of the corresponding technology industry, the demand for OLED panels has shown a rapid growth trend. OLED panels not only have inherent advantages such as self-luminescence, ultra-thinness, power saving, and bright colors, but can also achieve innovative designs such as full screens and flexible screens to meet the diversified needs of modern smartphones. With the popularity of OLED panels in the market, users and manufacturers are gradually raising the standards for panel performance. The panel's performance in brightness and color uniformity can be directly perceived subjectively and has become a key consideration. In terms of brightness uniformity, many existing compensation schemes have been able to achieve uniformity compensation effects that meet industry standards, including but not limited to OFFSET compensation, polynomial fitting compensation and other schemes. As for color uniformity, the existing compensation scheme is mainly based on the partition adjustment method. Based on the aforementioned brightness compensation effect, the mixed color picture is shot, and the screen is divided into multiple areas. The compensation adjustment of different areas is carried out according to the parameters calculated according to the shooting picture to improve the color uniformity performance. However, due to the differences in the response characteristics of different pixels and the different arrangement methods, the adjustment effect may not be ideal and the parameters between different panels are difficult to be uniformly applied. With the popularization of HDR video content and the stringent requirements of new technologies such as AR / VR on display quality, OLED panels with excellent color uniformity are increasingly in hot demand in the market. Summary of the invention

[0003] The present invention provides a sub-pixel color balance compensation method for an OLED display panel based on a De-Mura compensation technology, comprising: Step 1: Start, the brightness industrial camera takes the first brightness data shot; Step 2: Obtain brightness data of three channels R / G / B at different grayscales; Step 3: Perform brightness uniformity compensation processing; Step 4: Generate brightness uniformity compensation parameters and burning files, and burn the display driver integrated circuit; Step 5: Determine whether chromaticity uniformity correction is needed. If so, the chromaticity industrial camera performs a second chromaticity data capture, obtains different grayscale chromaticity data of the W screen, performs chromaticity uniformity compensation processing, generates chromaticity uniformity compensation coefficients and burning files, and burns the display driver integrated circuit; if not, end.

[0004] Furthermore, the brightness data in step 2 includes: A total of 3×5 groups of sub-pixel brightness data corresponding to the five gray levels of 32, 64, 128, 192, and 255 are used for the De-Mura preprocessing process.

[0005] Furthermore, the process of step 3 brightness uniformity compensation is as follows: The brightness data obtained in step 2 is subjected to the following fitting process: (i) The basic fitting formula is shown in formula (1):

[0006] in Indicates brightness, Represents grayscale, is the exponential parameter, is a linear parameter related to brightness. This formula is used to describe the relationship between different grayscales and brightness for subsequent compensation parameter calculation; (ii) The calculation process of the brightness uniformity compensation parameter at the sub-pixel level is shown in formula (2):

[0007] in In and Two parameters are used to describe the target brightness. In and Parameters are used to describe the compensation parameters of sub-pixels, based on the input grayscale The corresponding output grayscale of the sub-pixel is obtained by the relationship between the parameters ; (iii) The above formula (2) can be expressed in the form of the following formula (3):

[0008] make , formula (3) can be re-expressed as formula (4)

[0009] and The above calculation process is performed on the three sub-pixels R / G / B respectively, and the results are recorded as , , Take it as R / G / B.

[0010] Furthermore, the process of step 5 chromaticity uniformity compensation is as follows: By introducing the uniformity compensation factor , for the original input grayscale Correction is performed to improve the chromaticity uniformity. This process is expressed as formula (5):

[0011] To facilitate derivation, expand formula (5) to obtain formula (6):

[0012] Formula (6) is further expressed as formula (7):

[0013] In formula (7), Recorded as , and Recorded as , we get formula (8):

[0014] Combining formulas (4) and (8), we can see that when the chromaticity correction coefficient is obtained After that, based on the De-Mura process, the compensation parameters are modified for The chromaticity uniformity correction function is realized simultaneously.

[0015] Furthermore, the compensation parameters calculated in step 4 are compressed to generate a burning file and burned into the display driver integrated circuit, and the chromaticity industrial camera takes a second photo W picture: When the color conditions of different grayscale images are consistent, you only need to shoot one image; When the color conditions of different grayscale images are different, multiple images are captured, and W images are captured by a chromaticity industrial camera to obtain the brightness data of each pixel sub-pixel R / G / B under the W image. According to the R / G / B brightness data ratio coefficient of the selected target position, the average brightness data of the area is recorded as , , and the actual sub-pixel ratio coefficient is calculated from the photographic data: The first The sub-pixel brightness data of pixels is recorded as , , then the compensation adjustment coefficient of the sub-pixel is / , / , / , get the location Compensation coefficient at .

[0016] Furthermore, when shooting a single data, based on the compensation coefficient and the compensation parameters According to the formula Calculate R / G / B color uniformity compensation parameters ; When shooting multiple grayscales, the compensation coefficients calculated under different grayscales are Applied to the brightness data of R / G / B corresponding to the grayscale of the brightness industrial camera, the new and ,in Multiple grayscales for shooting; The final calculated OLED panel full sub-pixel compensation parameters and After compression, a burning file is generated and the display driver integrated circuit is burned.

[0017] The present invention also provides an OLED display panel sub-pixel color balance compensation system based on De-Mura compensation technology, including a display driver integrated circuit calculating compensation data: (1) Decompress the compensation parameters burned in step 4 to obtain the compensation parameters at the sub-pixel level:

[0018]

[0019]

[0020] in Respectively represent the actual resolution of the OLED panel corresponding to R / G / B sub-pixels; (2) Input data acquisition, denoted as ,in Take it as R / G / B; (3) According to the formula

[0021] Compensation calculation is performed on the R / G / B channels based on the compensation parameters and input data to obtain sub-pixel level ;

[0022] Output brightness and color uniformity compensation results for terminal display.

[0023] The present invention aims at improving chromaticity uniformity by adjusting the partitions, which may be affected by the differences in the response characteristics of different pixels and the different arrangements, resulting in unsatisfactory adjustment effects and difficulty in uniformly applying parameters between different panels; and the display driver integrated circuit (DDIC) needs to occupy additional digital circuit design area, resulting in increased power consumption. In the existing brightness De-Mura processing flow, the compensation coefficient for improving chromaticity uniformity is applied to the brightness uniformity compensation parameter, and the sub-pixel level chromaticity uniformity compensation can be achieved in the same way as the brightness uniformity compensation, and it is adaptive for the response characteristics of different pixels and different arrangements. At the same time, there is no need to increase the digital circuit design area, saving DDIC power consumption. DDIC only needs one calculation to simultaneously achieve brightness and chromaticity uniformity compensation of the OLED display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure shows the sub-pixel color balance compensation process of OLED display panel based on De-Mura compensation technology; Figure 2 Shown is the display driver integrated circuit compensation implementation flow. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] See also Figure 1-2 The present invention discloses a sub-pixel color balance compensation method for an OLED display panel based on De-Mura compensation technology, as shown in the process diagram. Figure 1 The luminance and chromaticity uniformity compensation parameter preprocessing part is shown.

[0027] The following steps are used to implement brightness uniformity compensation based on brightness data: First, a brightness industrial camera is used to capture three-channel R / G / B (Red / Green / Blue) with multiple grayscales (for example, 32 / 64 / 128 / 192 / 255 grayscales), a total of 3×5 groups of brightness data, and the captured data is used in the De-Mura preprocessing process to generate brightness uniformity compensation parameters and burning files, and then burn DDIC.

[0028] The following steps are used to realize the final chromaticity uniformity compensation coefficient based on the chromaticity data and the brightness uniformity compensation parameters: Based on the brightness uniformity compensation result, the W (White) grayscale (for example, 128 grayscale, the shooting grayscale can be increased according to the chromaticity performance) is captured by a chromaticity industrial camera to obtain the chromaticity data, and the shooting data is used in the De-Mura preprocessing process to generate the chromaticity uniformity compensation coefficient and act on the above brightness uniformity compensation parameters to generate the final burning file for synchronously improving the brightness and chromaticity uniformity performance, and burn the DDIC.

[0029] The specific implementation process is as follows: Step 1: Start, the brightness industrial camera takes the first brightness data shot; Step 2: Obtain brightness data of three channels R / G / B at different grayscales; Step 3: Perform brightness uniformity compensation processing; Step 4: Generate brightness uniformity compensation parameters and burning files, and burn the display driver integrated circuit; Step 5: Determine whether chromaticity uniformity correction is needed. If so, the chromaticity industrial camera performs a second chromaticity data capture, obtains different grayscale chromaticity data of the W screen, performs chromaticity uniformity compensation processing, generates chromaticity uniformity compensation coefficients and burning files, and burns the display driver integrated circuit; if not, end.

[0030] The brightness data in step 2 includes: A total of 3×5 groups of sub-pixel brightness data corresponding to the five gray levels of 32, 64, 128, 192, and 255 are used for the De-Mura preprocessing process.

[0031] Step 3 The process of brightness uniformity compensation is as follows: The acquired brightness data is subjected to the following fitting process: (i) The basic fitting formula is shown in formula (1):

[0032] in Indicates brightness, Represents grayscale, is the exponential parameter, is a linear parameter related to brightness. This formula is used to describe the relationship between different grayscales and brightness for subsequent compensation parameter calculation; (ii) The calculation process of the brightness uniformity compensation parameter at the sub-pixel level is shown in formula (2):

[0033] in In and Two parameters are used to describe the target brightness. In and Parameters are used to describe the compensation parameters of sub-pixels, based on the input grayscale The corresponding output grayscale of the sub-pixel is obtained by the relationship between the parameters ; (iii) The above formula (2) can be expressed in the form of the following formula (3):

[0034] make , formula (3) can be re-expressed as formula (4)

[0035] and The above calculation process is performed on the three sub-pixels R / G / B respectively, and the results are recorded as , , Take it as R / G / B.

[0036] Step 5 The process of color uniformity compensation is as follows: By introducing the uniformity compensation factor , for the original input grayscale Correction is performed to improve the chromaticity uniformity. This process is expressed as formula (5):

[0037] To facilitate derivation, expand formula (5) to obtain formula (6):

[0038] Formula (6) is further expressed as formula (7):

[0039] In formula (7), Recorded as , and Recorded as , we get formula (8):

[0040] Combining formulas (4) and (8), we can see that when the chromaticity correction coefficient is obtained After that, based on the De-Mura process, the compensation parameters are modified for The chromaticity uniformity correction function can be realized simultaneously.

[0041] The compensation parameters calculated in step 4 are compressed to generate a burning file and burned into the display driver integrated circuit, and the chromaticity industrial camera takes a second photo of the W screen.

[0042] The present invention supports flexible selection of shooting grayscale images, and determines the shooting image according to the chromaticity performance of the W image at different grayscales: When the color conditions of different grayscale images are consistent, you only need to shoot one image; When the color conditions of different grayscale images are different, multiple images are captured, and W images are captured by a chromaticity industrial camera to obtain the brightness data of each pixel sub-pixel R / G / B under the W image. According to the R / G / B brightness data ratio coefficient of the selected target position, the average brightness data of the area is recorded as , , and the actual sub-pixel ratio coefficient is calculated from the photographic data: The first The sub-pixel brightness data of pixels is recorded as , , then the compensation adjustment coefficient of the sub-pixel is / , / , / , get the location Compensation coefficient at .

[0043] When shooting single data, based on the compensation coefficient and the compensation parameters According to the formula Calculate R / G / B color uniformity compensation parameters ; When shooting multiple grayscales, the compensation coefficients calculated under different grayscales are Applied to the brightness data of R / G / B corresponding to the grayscale of the brightness industrial camera, the new and ,in It can capture multiple grayscales and take into account the uniformity of color at different grayscales.

[0044] The final calculated OLED panel full sub-pixel compensation parameters and After compression, a burning file is generated and the display driver integrated circuit is burned.

[0045] It should be noted that the actual compensation parameter calculation involves , , , Parameters such as R / G / B should be calculated separately based on the three channels.

[0046] In addition, the present invention also provides an OLED display panel sub-pixel color balance compensation system based on De-Mura compensation technology, which is used to implement an OLED display panel sub-pixel color balance compensation method based on De-Mura compensation technology, including a display driver integrated circuit calculating compensation data: (1) Decompress the compensation parameters burned in step 4 to obtain the compensation parameters at the sub-pixel level:

[0047]

[0048]

[0049] in Respectively represent the actual resolution of the OLED panel corresponding to R / G / B sub-pixels; (2) Input data acquisition, denoted as ,in Take it as R / G / B; (3) According to the formula ; Compensation calculation is performed on the R / G / B channels based on the compensation parameters and input data to obtain sub-pixel level ; Output brightness and color uniformity compensation results for terminal display.

[0050] The specific implementation process is as follows Figure 2 As shown: (1) Start; (2) DDIC reads the compensation data stored in the memory; (3) Determine whether the chromaticity uniformity is corrected. If so, perform uniformity compensation on brightness and chromaticity; if not, perform compensation on brightness uniformity only; (4) After the above processing is completed, the process ends.

[0051] The technical effect of the present invention is that based on the fitting parameters that characterize the data characteristics combined with the chromaticity compensation coefficient, an accurate fitting model is established to achieve perfect integration with the hardware system. The chromaticity uniformity of the OLED panel is significantly improved, and only one calculation is required to generate accurate compensation predictions at the sub-pixel level. By integrating the chromaticity balance coefficient through the De-Mura process, the occupancy of computing resources is significantly reduced, and the performance of the hardware equipment is significantly improved. The system can also flexibly adjust the captured image according to the needs of the actual display device, and by reasonably calculating the correction coefficient, it ensures that each output color in the subsequent color processing process can be restored with high precision and uniformity, ultimately achieving high color consistency performance of the OLED display panel.

[0052] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the appended claims and their equivalents.

Claims

1. A sub-pixel color balance compensation method for an OLED display panel based on De-Mura compensation technology, characterized in that: include: Step 1: Start, the brightness industrial camera takes the first brightness data shot; Step 2: Obtain brightness data of three channels R / G / B at different grayscales; Step 3: Perform brightness uniformity compensation processing; Step 4: Generate brightness uniformity compensation parameters and burning files, and burn the display driver integrated circuit; Step 5: Determine whether chromaticity uniformity correction is needed. If so, the chromaticity industrial camera performs a second chromaticity data capture, obtains different grayscale chromaticity data of the W screen, performs chromaticity uniformity compensation processing, generates chromaticity uniformity compensation coefficients and burning files, and burns the display driver integrated circuit; if not, end.

2. The method for sub-pixel color balance compensation of an OLED display panel based on De-Mura compensation technology according to claim 1, characterized in that: The brightness data in step 2 includes: A total of 3×5 groups of sub-pixel brightness data corresponding to the five gray levels of 32, 64, 128, 192, and 255 are used for the De-Mura preprocessing process.

3. The method for sub-pixel color balance compensation of an OLED display panel based on De-Mura compensation technology according to claim 2, characterized in that: Step 3 The process of brightness uniformity compensation is as follows: The brightness data obtained in step 2 is subjected to the following fitting process: (i) The basic fitting formula is shown in formula (1): ； in Indicates brightness, Represents grayscale, is the exponential parameter, is a linear parameter related to brightness. This formula is used to describe the relationship between different grayscales and brightness for subsequent compensation parameter calculation; (ii) The calculation process of the brightness uniformity compensation parameter at the sub-pixel level is shown in formula (2): ； in In and Two parameters are used to describe the target brightness. In and Parameters are used to describe the compensation parameters of sub-pixels, based on the input grayscale The corresponding output grayscale of the sub-pixel is obtained by the relationship between the parameters ; (iii) The above formula (2) is expressed in the form of the following formula (3): ； make , formula (3) is re-expressed as formula (4) ； and The above calculation process is performed on the three sub-pixels R / G / B respectively, and the results are recorded as , , Take it as R / G / B.

4. The method for sub-pixel color balance compensation of an OLED display panel based on De-Mura compensation technology according to claim 3, characterized in that: Step 5 The process of color uniformity compensation is as follows: By introducing the uniformity compensation factor , for the original input grayscale Correction is performed to improve the chromaticity uniformity. This process is expressed as formula (5): ； To facilitate derivation, expand formula (5) to obtain formula (6): ； Formula (6) is further expressed as formula (7): ； In formula (7), Recorded as , and Recorded as , we get formula (8): ； Combining formulas (4) and (8), we can see that when the chromaticity correction coefficient is obtained After that, based on the De-Mura process, the compensation parameters are modified for The chromaticity uniformity correction function is realized simultaneously.

5. The method for sub-pixel color balance compensation of an OLED display panel based on De-Mura compensation technology according to claim 4, characterized in that: The compensation parameters calculated in step 4 are compressed to generate a burning file and burned into the display driver integrated circuit. The chromaticity industrial camera takes a second photo of the W screen: When the color conditions of different grayscale images are consistent, you only need to shoot one image; When the color conditions of different grayscale images are different, multiple images are captured, and W images are captured by a chromaticity industrial camera to obtain the brightness data of each pixel sub-pixel R / G / B under the W image. According to the R / G / B brightness data ratio coefficient of the selected target position, the average brightness data of the area is recorded as , , and the actual sub-pixel ratio coefficient is calculated from the photographic data: The first The sub-pixel brightness data of pixels is recorded as , , then the compensation adjustment coefficient of the sub-pixel is / , / , / , get the location Compensation coefficient at .

6. The method for sub-pixel color balance compensation of an OLED display panel based on De-Mura compensation technology according to claim 5, characterized in that: When shooting single data, based on the compensation coefficient and the compensation parameters According to the formula Calculate R / G / B color uniformity compensation parameters ; When shooting multiple grayscales, the compensation coefficients calculated under different grayscales are Applied to the brightness data of R / G / B corresponding to the grayscale of the brightness industrial camera, the new and ,in Multiple grayscales for shooting; The final calculated OLED panel full sub-pixel compensation parameters and After compression, a burning file is generated and the display driver integrated circuit is burned.

7. A sub-pixel color balance compensation system for an OLED display panel based on De-Mura compensation technology, used to implement a sub-pixel color balance compensation method for an OLED display panel based on De-Mura compensation technology as described in any one of claims 1 to 6, characterized in that: Display driver IC calculation compensation data: (1) Decompress the compensation parameters burned in step 4 to obtain the compensation parameters at the sub-pixel level: ； ； ； in Respectively represent the actual resolution of the OLED panel corresponding to R / G / B sub-pixels; (2) Input data acquisition, denoted as ,in Take it as R / G / B; (3) According to the formula ； Compensation calculation is performed on the R / G / B channels based on the compensation parameters and input data to obtain sub-pixel level ; Output brightness and color uniformity compensation results for terminal display.

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