A display screen Demura method, system and OLED display screen

Abstract

The application provides a display screen Demura method, a system and an OLED display screen, and relates to the technical field of display. By establishing the corresponding relationship between the display screen and the display panel, after obtaining the Mura data of each display screen, the display panel Mura data is formed. The display panel is divided into multiple display panel abnormal parts according to the Mura data gathering degree, and then the display screen Demura area of each display screen is generated according to the display panel abnormal part. The display screen Demura area at least includes a dense Demura area and a sparse Demura area. A small area is used for the Mura dense area, and a better Demura effect can be obtained. A larger pixel area is used for the Mura sparse area, which does not affect the Demura effect and can reduce the storage space.

Description

Technical Field

[0001] This invention belongs to the field of display technology, and in particular relates to a display screen Demura method, system, and OLED display screen. Background Technology

[0002] OLED (Organic Light Emitting Diode) has been widely used in high-performance displays due to its advantages such as vibrant colors, low power consumption, and thinness. However, during the fabrication process on large-area glass substrates, limitations in the crystallization process cause non-uniformity in electrical parameters such as threshold voltage and mobility of TFTs. This leads to differences in current and brightness within the display devices, resulting in the Mura phenomenon. Consequently, uneven brightness and color shifts may occur during display.

[0003] Demura is a key technology in display manufacturing, used to eliminate screen brightness or color unevenness (Mura) through pixel-level brightness compensation. Its core principle is based on Gamma calibration and grayscale compensation, combined with OTP (One-Time Programmable) technology to achieve precise repair, effectively improving display uniformity and reducing product defect rates. It is widely used in LCD / OLED screen manufacturing. Figure 1 .

[0004] In principle, performing Demura processing on every pixel can achieve excellent display results; however, if Demura is performed on all pixels of the display screen, the amount of compensation data that needs to be stored is enormous, which requires a larger capacity Flash ROM to store the Demura compensation data, thus increasing costs. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to provide a DeMura method, system and OLED display screen that can reduce the amount of DeMura compensation data while ensuring display effect.

[0006] First invention: The present invention provides a demura method for a display screen, the display screen being formed by cutting a display panel, comprising:

[0007] Establish a correspondence between the display screen and the display panel; the correspondence includes at least the display screen number, the display panel number to which it belongs, and the position of the display screen in the display panel;

[0008] Each display screen is inspected using a camera to obtain Mura data for each display screen;

[0009] Based on the correspondence between the display screen and the display panel, the Mura data of each display screen belonging to the same display panel number is merged to form the display panel Mura data;

[0010] Based on the Mura data of the display panel, multiple abnormal areas of the display panel are formed according to the degree of Mura data aggregation. Each abnormal area of ​​the display panel is a continuous region, and the Mura data in the continuous region is significantly more than that in other areas.

[0011] Based on the abnormal parts of the display panel, a display Demura region is generated for each display screen; the display Demura region includes at least a dense Demura region and a sparse Demura region; the dense Demura region has fewer pixels and more Muras than the sparse Demura region; the area in the display screen corresponding to the abnormal parts of the display panel is divided according to the smallest pixel area;

[0012] Each display screen's Demura region generates display screen Demura data using a Demura compensation algorithm;

[0013] The Demura data for the display screen is compressed and then burned into the display screen's Flash ROM.

[0014] Furthermore, in the display panel, the area where the display screen is located is the display area, and the rest is the non-display area; the display area inputs the Mura data of the display screen, and the non-display area does not perform Demura.

[0015] Furthermore, for defective cut display screens, the corresponding display panel area is set as a non-display area.

[0016] Furthermore, when forming the Mura data of the display panel, the non-display area between two adjacent displays is deleted, so that the Mura data of the two adjacent displays are connected.

[0017] Furthermore, the position of the display screen in the display panel is determined by the coordinates of the center point of the display screen pixel in the corresponding pixel position in the display panel.

[0018] Furthermore, if the display screen and the abnormal part of the display panel have an intersection, after generating the display screen Demura data, the display screen using the above display screen Demura data is detected again by the camera. After multiple iterations, the display screen Demura effect is achieved as required.

[0019] Furthermore, the abnormal part of the display panel is elongated, and the smallest area of ​​the display screen is 1×1 pixel.

[0020] Furthermore, the trained model is used to segment abnormal areas of the display panel, and the model is trained using an RNN neural network.

[0021] In a second aspect, the present invention provides a Demura system for a display screen, the display screen being formed by cutting a display panel, comprising:

[0022] The display screen and display panel relationship establishment module establishes the correspondence between the display screen and the display panel; the correspondence includes at least the display screen number, the corresponding display panel number, and the position of the display screen in the display panel;

[0023] The display screen Mura data acquisition module uses a camera to detect each display screen and acquire Mura data for each display screen;

[0024] The display panel Mura data generation module merges the Mura data of each display screen belonging to the same display panel number according to the correspondence between the display screen and the display panel to form the display panel Mura data.

[0025] The display panel abnormality determination module, based on the display panel Mura data, will form multiple display panel abnormalities according to the degree of Mura data aggregation. The display panel abnormality is a continuous area, and the Mura data in the continuous area is significantly more than in other areas.

[0026] The display Demura region generation module generates a display Demura region for each display based on the abnormal parts of the display panel. The display Demura region includes at least a dense Demura region and a sparse Demura region. The dense Demura region has fewer pixels and more Muras than the sparse Demura region. The area in the display corresponding to the abnormal parts of the display panel is divided according to the smallest pixel area.

[0027] The display screen Demura data generation module generates display screen Demura data for each display screen Demura region using a Demura compensation algorithm.

[0028] The Demura data for the display screen is compressed and then burned into the display screen's Flash ROM.

[0029] In addition, the present invention also provides an OLED display screen, including a Flash ROM and a Driver IC. The Flash ROM stores the display screen Demura data obtained by the method, and the Driver IC imports the compressed Demura data from the Flash ROM.

[0030] Beneficial effects:

[0031] The Demura method for displays provided by this invention establishes a correspondence between displays and display panels. After obtaining the Mura data for each display, it forms the Mura data for the display panel. Multiple abnormal areas of the display panel are then formed according to the degree of Mura data aggregation. Based on these abnormal areas, a corresponding display Demura region is generated for each display.

[0032] Using small regions for dense Mura areas can achieve better Demura effects, while using larger pixel regions for sparse Mura areas can reduce storage space without affecting the Demura effect.

[0033] The Demura system and OLED display provided by this invention also have the above-mentioned effects. Attached Figure Description

[0034] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0035] Figure 1 This is a schematic diagram of the Demura principle;

[0036] Figure 2 This is a flowchart of the Demura method according to Embodiment 1 of the present invention;

[0037] Figure 3 This is a schematic diagram illustrating the relationship between the display panel and the display screen in Embodiment 1 of the present invention; Detailed Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. The principles and features of the present invention are described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0039] Mura exhibits many phenomena, but in summary, it mainly involves uneven color / brightness on the screen in various forms, including color cast in fixed areas, and brightness and darkness defects in fixed areas.

[0040] To overcome the shortcomings of existing technologies, the method of performing Demura processing on each pixel is abandoned, and processing multiple pixels is adopted to reduce storage space usage. This processing method has its rationale.

[0041] First, let's analyze the causes of Mura. It's due to problems in the panel and finished product manufacturing process. Because display devices are composed of multiple materials and substrates, and the bonding process of different layers cannot be absolutely precise each time, any problem in production can lead to the screen Mura phenomenon. These include impurities in the liquid crystal layer, uneven distribution of certain substrates during manufacturing, uneven TFT thickness, uneven backlight distribution, and inherent defects in the panel itself.

[0042] Extensive analysis of display screen mura data reveals that the location of muras is not random; different muras exhibit a certain correlation, and their distribution is not uniform, but rather includes clustered and sparse areas. Therefore, dividing the display screen into regions and using small 1×1 or 2×2 pixel areas for densely populated mura regions can achieve better demura effects, while using larger pixel areas for sparsely populated mura regions can both maintain the demura effect and reduce storage space.

[0043] After testing, this invention found that if the Mura data obtained by shooting each display screen with an industrial camera is divided into regions, the Demura effect and storage space are improved, but there may be problems in dividing the Mura data at the edge of the display screen.

[0044] Data analysis of multiple displays formed from a single display panel revealed a strong correlation between the locations of mura (mura) phenomena, particularly among adjacent displays. This is because, during the same batch production process, the same display panel, due to the identical manufacturing process, will simultaneously affect multiple adjacent displays when mura occurs, regardless of the cause. If each display is processed individually, the resulting area does not reflect the actual area affected by mura phenomena that may arise from various stages of display panel production, ultimately leading to an unreasonable area division.

[0045] Therefore, the idea of ​​this invention is to address the root cause of mura caused by the display screen and effectively demura the display screen.

[0046] Example 1

[0047] like Figure 2As shown, this embodiment is a Demura method for an OLED display. Using the analysis approach described above, a correspondence is first established between the display panel and the multiple displays formed after cutting. This correspondence includes at least the display number, the display panel number to which it belongs, and the position of the display within the display panel. Each display panel has a unique number, and each display segmented from that display panel also has a unique number. Within the display panel, the displays can be numbered in a matrix format (rows and columns) according to the segmented display areas. The display number uniquely determines its position and adjacency within the display panel.

[0048] The position of the display screen within the display panel can also be determined by the coordinates of the center point of each pixel on the display screen within the corresponding pixel position on the display panel. The positions of other pixels on the display screen are calculated based on the coordinates of the center point.

[0049] After the display panel is cut, the inspection image of each display is captured by a high-precision, high-resolution CCD camera. For OLED displays, the Demura camera generally requires a frame rate of 15fps or higher.

[0050] By analyzing the pixel color distribution characteristics based on camera-collected data, the gamma index value of each pixel is calculated. Based on this index, relevant algorithms are used to identify the mura.

[0051] Based on the correspondence between the display screen and the display panel, the Mura data of each display screen belonging to the same display panel number is merged to form the display panel Mura data.

[0052] The distribution of Mura data in the display panel is analyzed, and regions are divided according to the degree of Mura data aggregation. Abnormally dense Mura areas can be caused by various reasons, whether it's due to oxygen or moisture leakage, or processing issues, all of which can affect the light-emitting units on the substrate within a certain area. By reconstructing the Mura data of each display panel according to its original position in the original display panel before cutting, a comprehensive understanding of all Mura phenomena can be achieved at the display panel level.

[0053] The display panel will be classified into abnormal areas based on the degree of Mura data aggregation. These abnormal areas can be elongated, regular curves, or other arbitrary shapes, and can be derived from historical experience in the production process or fitted based on the Mura data aggregation. The principle behind forming continuous areas is that abnormal conditions formed during production often appear continuously according to certain rules due to process factors.

[0054] The display panel will be divided into multiple abnormal areas according to the degree of Mura data aggregation. Each abnormal area is a continuous region with significantly more Mura data than other areas.

[0055] Based on the abnormal parts of the display panel, a display Demura region is generated for each display screen. The display Demura region includes at least a dense Demura region and a sparse Demura region. The dense Demura region has fewer pixels and more Muras than the sparse Demura region. The area in the display screen that intersects with the abnormal parts of the display panel is divided into the smallest pixel area, such as 1×1 pixels, so that Mura abnormalities can be captured finely, thereby accurately performing Demura compensation.

[0056] For abnormal areas outside the display panel, they can be divided into different Demura regions depending on the situation. For large areas with very few Demuras, large-sized pixel regions can be used to divide them, which can reduce storage space and have less impact on the Demura processing in that area.

[0057] like Figure 3 As shown, 1 represents the display panel, 2 represents the display screen, 3 represents the concentrated Mura area formed by black and gray across the three displays on the display panel, and 4 represents the area with fewer Mura. It should be noted that the diagram is for illustrative purposes only; the black blocks do not refer to a single pixel size, but rather to a region containing a relatively concentrated Mura, while the gray blocks indicate a region containing fewer Mura. In the overall identification of the display panel, the black and gray blocks clearly form a concentrated Mura area, so in identifying abnormal areas of the display panel's demura, the abnormal areas will be included within the gray blocks. However, if judging only from the upper left display, it is possible to judge the Mura distribution based on the gray blocks as having relatively sparse Mura. This is partly because the gray blocks are near the edge, lacking data support outside the edge; partly due to factors such as camera resolution; and partly because flexible OLED screens often use curved edges, affecting the judgment of edge Mura. Regardless of the reason, judging from the entire display panel is clearly more accurate in reflecting the true Mura distribution than judging only a single display. For the same Mura data in the gray area of ​​the display, dividing it into larger pixel areas will inevitably affect the demura effect in that area. If, based on the overall assessment, the system is deemed to contain abnormal areas requiring focused processing, then a smaller pixel area will be used for more precise processing. Alternatively, it's more likely that the detection will be repeated using other methods to more accurately reflect the Mura phenomenon, such as the iterative processing method described below.

[0058] Based on the display panel's Demura region, a corresponding display Demura region is generated for each display screen. Then, display screen Demura data is generated using a Demura compensation algorithm according to each display screen's Demura region.

[0059] The Demura data of the display screen is compressed and burned into the display screen's Flash ROM. When in use, the Driver IC imports the compressed Demura data from the Flash ROM to perform Demura on the display screen.

[0060] In the display panel, the area where the display screen is located is the display area, and the rest is the non-display area. The display area inputs the Mura data of the display screen, while the non-display area does not perform Demura.

[0061] Optionally, defective displays are inevitable during processing. For defective displays, it is not necessary to collect Mura data. The display panel area to which the defective display belongs can be directly set as a non-display area.

[0062] As is well known, regardless of the cutting method used, the edges of the display screen will inevitably be damaged during the cutting process. In other words, there is a non-display area between two adjacent display screens.

[0063] For better partitioning, the non-display area between two adjacent displays should be as small as possible.

[0064] Preferably, considering the display panel as a whole, if a row (or column) in the display panel is entirely non-display area, then that row (or column) is deleted, thereby making the Mura data of adjacent displays closer together, and reflecting the true shape of the area more accurately when classifying by the degree of Mura clustering.

[0065] For display panels produced in the same factory, due to the relatively fixed manufacturing processes and techniques, different batches of display panels exhibit a certain correlation in the distribution of the Mura phenomenon. To better optimize the demura region segmentation, an RNN neural network can be used to train a demura region segmentation model on a large amount of Mura data. Using a machine-trained model to segment the demura regions of display panels can effectively match the distribution of different regions with the Mura data, improving efficiency while avoiding the arbitrariness of manual segmentation.

[0066] Furthermore, production lines currently typically use industrial cameras to capture brightness information of the display screen at several gray levels across the R, G, and B channels. Clearly, higher camera precision can obtain accurate Mura data, thereby improving demura compensation. However, due to cost and resource limitations, the precision of the imaging equipment still cannot achieve good compensation results with a single data acquisition. In particular, if the display screen has dense demura areas, generating display demura data and then re-inspecting the screen using that data with a camera, through multiple iterations until the demura effect meets requirements, can better eliminate Mura phenomena in abnormal areas of the display panel.

[0067] Example 2

[0068] This embodiment is a Demura system for an OLED display, which includes:

[0069] The display screen and display panel relationship establishment module establishes the correspondence between the display screen and the display panel; the correspondence includes at least the display screen number, the corresponding display panel number, and the position of the display screen in the display panel;

[0070] The display screen Mura data acquisition module uses a camera to detect each display screen and acquire Mura data for each display screen;

[0071] The display panel Mura data generation module merges the Mura data of each display screen belonging to the same display panel number according to the correspondence between the display screen and the display panel to form the display panel Mura data.

[0072] The display panel abnormality determination module, based on the display panel Mura data, will form multiple display panel abnormalities according to the degree of Mura data aggregation. The display panel abnormality is a continuous area, and the Mura data in the continuous area is significantly more than in other areas.

[0073] The display Demura region generation module generates a display Demura region for each display based on the abnormal parts of the display panel. The display Demura region includes at least a dense Demura region and a sparse Demura region. The dense Demura region has fewer pixels and more Muras than the sparse Demura region. The area in the display corresponding to the abnormal parts of the display panel is divided according to the smallest pixel area.

[0074] The display screen Demura data generation module generates display screen Demura data according to the Demura region of each display screen using a Demura compensation algorithm;

[0075] The Demura data for the display screen is compressed and then burned into the display screen's Flash ROM.

[0076] Example 3

[0077] The present invention also provides an OLED display screen, including a Flash ROM and a Driver IC. The Flash ROM stores the display screen Demura data obtained by the method, and the Driver IC imports the compressed Demura data from the Flash ROM.

[0078] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for demurating a display screen, the display screen being formed by cutting a display panel, characterized in that, include: Establish a correspondence between the display screen and the display panel; the correspondence includes at least the display screen number, the display panel number to which it belongs, and the position of the display screen in the display panel; Each display screen is inspected using a camera to obtain Mura data for each display screen; Based on the correspondence between the display screen and the display panel, the Mura data of each display screen belonging to the same display panel number is merged to form the display panel Mura data; Based on the Mura data of the display panel, multiple abnormal areas of the display panel are formed according to the degree of Mura data aggregation. Each abnormal area of ​​the display panel is a continuous region, and the Mura data in the continuous region is significantly more than that in other areas. Based on the abnormal parts of the display panel, generate the corresponding display Demura area for each display screen; The display screen's Demura area includes at least a dense Demura area and a sparse Demura area; the dense Demura area has fewer pixels and a greater number of Mura than the sparse Demura area; the area in the display screen corresponding to the abnormal part of the display panel is divided according to the smallest pixel area. Each display screen's Demura region generates display screen Demura data using a Demura compensation algorithm; The Demura data for the display screen is compressed and then burned into the display screen's Flash ROM.

2. The method according to claim 1, characterized in that, In the display panel, the area where the display screen is located is the display area, and the rest is the non-display area; the display area inputs the Mura data of the display screen, while the non-display area does not perform Demura.

3. The method according to claim 2, characterized in that, For defective cut display screens, the corresponding display panel area is set as a non-display area.

4. The method according to claim 3, characterized in that, When generating Mura data for the display panel, the non-display area between two adjacent displays is deleted, so that the Mura data of the two adjacent displays are connected.

5. The method according to claim 1, characterized in that, The position of the display screen in the display panel is determined by the coordinates of the center point of the display screen pixel in the corresponding pixel position in the display panel.

6. The method according to claim 1, characterized in that, If the display screen and the abnormal part of the display panel have an overlap, after generating the display screen Demura data, the display screen using the above display screen Demura data is inspected again by the camera. This process is repeated multiple times until the display screen Demura effect meets the requirements.

7. The method according to claim 1, characterized in that, The abnormal area of ​​the display panel is elongated and the smallest area of ​​the display screen is 1×1 pixel.

8. The method according to claim 1, characterized in that, The abnormal parts of the display panel are segmented using a trained model, which is trained using an RNN neural network.

9. A Demura system for a display screen, the display screen being formed by cutting a display panel, characterized in that, include: The display screen and display panel relationship establishment module establishes the correspondence between the display screen and the display panel; the correspondence includes at least the display screen number, the corresponding display panel number, and the position of the display screen in the display panel; The display screen Mura data acquisition module uses a camera to detect each display screen and acquire Mura data for each display screen; The display panel Mura data generation module merges the Mura data of each display screen belonging to the same display panel number according to the correspondence between the display screen and the display panel to form the display panel Mura data. The display panel abnormality determination module, based on the display panel Mura data, will form multiple display panel abnormalities according to the degree of Mura data aggregation. The display panel abnormality is a continuous area, and the Mura data in the continuous area is significantly more than in other areas. The display screen Demura area generation module generates the display screen Demura area for each display screen based on the abnormal parts of the display panel. The display screen's Demura area includes at least a dense Demura area and a sparse Demura area; the dense Demura area has fewer pixels and a greater number of Mura than the sparse Demura area; the area in the display screen corresponding to the abnormal part of the display panel is divided according to the smallest pixel area. The display screen Demura data generation module generates display screen Demura data for each display screen Demura region using a Demura compensation algorithm. The Demura data for the display screen is compressed and then burned into the display screen's Flash ROM.

10. An OLED display screen, characterized in that, It includes a Flash ROM and a Driver IC. The Flash ROM stores display Demura data obtained by the method described in any one of claims 1-8, and the Driver IC imports the compressed Demura data from the Flash ROM.

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