A method and device for detecting weak abnormal points of a display panel

Abstract

The present invention discloses a method for detecting weak abnormal points of a display panel, the method comprising: importing a test image into a display panel, photographing the display panel as a first test result, and marking a first area; the first area is larger than a pixel; importing a monochrome image into the display panel, photographing the display panel as a second test result; marking a first pixel in the first area, marking the first pixel and its adjacent pixels in the second test result, and calculating the difference in grayscale values ​​between the first pixel and its adjacent pixels; when the minimum value of the difference in grayscale values ​​is greater than a second threshold value, it is considered that the points constituted by the first area are abnormal points of the corresponding color of the monochrome image. The present invention extracts the point with the largest grayscale value difference among the abnormal points as a representative, analyzes the color of the pixel, and can effectively classify the abnormal points, thereby improving the efficiency of abnormal point classification.

Description

Technical Field

[0001] The present invention relates to the field of display panel detection technology, and more specifically, to a method and device for detecting weak abnormal points of a display panel. Background Art

[0002] With the rapid development of the industrial field, the inspection tasks of LCD and OLED panels have gradually changed from manual inspection to machine inspection. In the process of machine inspection, the system commonly used is the AOI system (Automated Optical Inspection), which plays the role of manual inspection to perform a series of high-intensity and high-precision inspection tasks, greatly improving production efficiency and liberating productivity.

[0003] The most common detection items in panel detection are bright spot and dark spot detection. Bright spots refer to spots that appear bright in a black screen, while dark spots refer to spots that appear black in a white screen. Each pixel in the panel is composed of several pixel units according to certain rules. When bright spots or dark spots appear in the panel, it is necessary to further analyze the causes of the bright spots and dark spots, which involves a classification method for bright spots or dark spots. However, the prior art lacks a classification method for bright spots or dark spots. Summary of the invention

[0004] In response to at least one defect or improvement need in the prior art, the present invention provides a method, device and storage medium for detecting faint abnormal points in a display panel. By extracting the point with the largest grayscale value difference among the abnormal points as a representative and analyzing the color of the pixel point, the abnormal points can be effectively classified, thereby improving the efficiency of abnormal point classification.

[0005] To achieve the above object, according to a first aspect of the present invention, a method for detecting weak abnormal points of a display panel is provided, the method comprising:

[0006] S1. Importing the test image into the display panel, photographing the display panel as a first test result, marking the first area; determining whether the first area is larger than one pixel, and if so, proceeding to subsequent steps;

[0007] The first area is an area where the difference between the grayscale value actually captured in the first test result and the grayscale value theoretically captured in the first test result is greater than a first threshold;

[0008] S2. The monochrome image is imported into the display panel, and the display panel is photographed as a second test result;

[0009] S3. Mark a first pixel in the first area, mark the first pixel and its adjacent pixels in the second test result, and calculate the difference in grayscale values ​​between the first pixel and its adjacent pixels; when the minimum value of the difference in grayscale values ​​is greater than a second threshold, the point constituted by the first area is considered to be an abnormal point of the corresponding color of the monochrome image; wherein the first pixel is the pixel having the largest absolute value of the difference between the grayscale value in the first area and the average grayscale value of all pixels in the first test result.

[0010] Furthermore, the method for detecting weak abnormal points of the display panel further includes:

[0011] The monochrome image is an image composed of colors corresponding to pixel units of the display panel.

[0012] Furthermore, the method for detecting weak abnormal points of the display panel further includes:

[0013] When the pixel units of the display panel are red, green and blue, the monochrome images are (255, 0, 0), (0, 255, 0) and (0, 0, 255) respectively.

[0014] Furthermore, the method for detecting weak abnormal points of the display panel further includes:

[0015] S4. Replace the monochrome image, and repeat steps S2-S3 until the monochrome images of all colors are tested.

[0016] Furthermore, the method for detecting weak abnormal points of the display panel further includes:

[0017] According to the test result, the points formed by the first area are one of single-color abnormal points or multi-color abnormal points.

[0018] Furthermore, the method for detecting weak abnormal points of the display panel further includes:

[0019] The second threshold is set according to the pixel unit arrangement mode of the display panel and / or the test requirement.

[0020] Furthermore, the method for detecting weak abnormal points of the display panel further includes:

[0021] When the camera is used for shooting m pixels are given to the display panel n When imaging a pixel unit, after converting the actual pixel points in the first test result and the second test result into equivalent pixel points, the equivalent pixel points of the first test result and the equivalent pixel points of the second test result are used to perform steps S1-S3.

[0022] According to a second aspect of the present invention, there is also provided a device for detecting weak abnormal points of a display panel, comprising:

[0023] a camera module configured to obtain a display photo of the display panel;

[0024] A display panel control module configured to input a test pattern or a monochrome pattern to the display panel;

[0025] A calculation and analysis module is configured to obtain the shooting results of the camera and classify the abnormal points of the display panel according to the steps of any of the above methods.

[0026] According to the third aspect of the present invention, there is also provided a device for detecting faint abnormal points of a display panel, which includes at least one processing unit and at least one storage unit, wherein the storage unit stores a computer program, and when the computer program is executed by the processing unit, the processing unit executes the steps of any one of the above-mentioned methods.

[0027] According to a fourth aspect of the present invention, there is also provided a storage medium storing a computer program executable by an access authentication device, wherein when the computer program runs on the access authentication device, the access authentication device executes the steps of any one of the above methods.

[0028] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0029] (1) The present invention provides a method for detecting weak abnormal points on a display panel, which extracts the point with the largest grayscale value difference among the abnormal points as a representative, analyzes the color of the pixel point, and then effectively classifies the abnormal points, thereby improving the efficiency of abnormal point classification;

[0030] (2) The present invention provides a method for detecting faint abnormal points on a display panel. When the resolution of the camera and the display panel cannot correspond one to one, the method converts the image to detect the faint abnormal points on the display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A schematic diagram of a flow chart of a method for detecting weak abnormal points of a display panel provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of shooting for bright spot detection provided by an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of a bright spot provided by an embodiment of the present invention;

[0035] Figure 4 An enlarged schematic diagram of a bright spot provided by an embodiment of the present invention;

[0036] Figure 5 A schematic diagram of the relationship between camera pixels and display panel pixel units provided by an embodiment of the present invention;

[0037] Figure 6 A schematic diagram of the relationship between another camera pixel point and a display panel pixel unit provided by an embodiment of the present invention;

[0038] Figure 7 A schematic diagram of the relationship between another camera pixel point and a display panel pixel unit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] The terms "first", "second", "third", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0041] Common abnormal points on display panels are bright spots and dark spots. Bright spots are points that appear bright on a black screen. The reason for their occurrence is that some pixel units emit light when they should not. Dark spots are the opposite of bright spots. They appear black on a white screen. They are points that some pixel units do not emit light when they should. Both bright spots and dark spots are defects in display panels. Therefore, it is necessary to detect bright spots and dark spots before leaving the factory.

[0042] Different display panels use different pixel unit arrangements. For example, the most common arrangement for LCD screens is the RGB arrangement, while there are many different arrangements for OLED screens, such as Pentile arrangement, Diamond arrangement, or Delta arrangement. Under different arrangements, the color type, size, and arrangement of pixel units are different, so the causes of bright spots and dark spots are also different, and the methods of solving bright spots and dark spots are also different. Therefore, it is necessary to classify the bright spots and dark spots of different display panels, such as red bright spots, blue dark spots, etc., to help with their subsequent repair and adjustment.

[0043] like Figure 1 As shown in FIG. 1 , as the first embodiment of the present invention, a method for detecting weak abnormal points on a display panel is provided. In this embodiment, the common RGB arrangement of an LCD screen is taken as an example. Taking the classification of bright spots as an example, firstly, an image with a gray value of 10, that is, an image with an RGB value of (10, 10, 10) is imported into the display panel to be tested. At this time, the display panel should theoretically display nearly black, such as Figure 2 When the camera is used to shoot the display panel, the image obtained should be close to completely black. When a bright spot appears, the grayscale value of the bright spot area will be significantly higher than that of other areas of the panel, such as Figure 3-4 As shown. Figure 3 This is a partial picture of the panel bright spot detection. You can see that there is a bright spot in the white circle. Figure 4 It is a partial enlarged image of the area. It can be seen that the bright spot is displayed as multiple pixels in the camera. There are many methods for bright spot detection. In this embodiment, the method of gray value comparison is selected to delineate the bright spot area. The screen photo taken by the above camera is recorded as the first test result L0, and the bright spot area is the first area.

[0044] In the L0 image, when the bright spot area is larger than one pixel, a pixel with the largest grayscale value can be found in the bright spot area. Because the L0 image is close to black, the average grayscale value of each point in the L0 image will be very small. For example, it should be close to (10,10,10) under ideal conditions. Therefore, by determining the difference between the grayscale value of each pixel in the bright spot area and the average grayscale value of the entire image, the pixel with the largest grayscale value in the L0 image can be extracted as the first pixel.

[0045] Similarly, when the test item is the dark spot of the display panel, that is, when the dark spot of the display panel is to be classified, it is only necessary to change the initially imported picture from a picture with a grayscale value of 10 to a picture with a grayscale value of 255. At this time, the pixel point extracted is the pixel point with the smallest grayscale value. Based on the same principle, the pixel point with the smallest grayscale value in the first test result can still be extracted as the first pixel point by judging the difference between the grayscale value of each pixel point in the dark spot area and the average grayscale value of the entire image. Those skilled in the art can also understand that the grayscale values ​​of the test images used for the bright spot test and the dark spot test are preferably (10, 10, 10) and (255, 255, 255) as in the above embodiments, and other settings may also be possible.

[0046] Because the LCD screen is arranged in RGB format, its pixel units only have three types: red, green and blue. Therefore, it is only necessary to prepare red, blue and green color images for testing. Here, we take the import of the red image, that is, the image with RGB value (255,0,0) as an example. After importing the red image, take a photo with a camera to get a new image, recorded as R255. When the distance between the panel and the camera and the parameters of the camera remain unchanged, it is easy to obtain the position of the first pixel in R255 and its adjacent pixels. The R255 image is a grayscale image. Therefore, after locating the first pixel, the next step is to obtain the grayscale value of the pixel in the R255 image and the grayscale value of its adjacent pixels, and compare the difference between the grayscale values ​​of the first pixel and its adjacent pixels by making a difference. When the minimum value of the difference in grayscale values ​​is greater than the second threshold, it is considered that the point composed of the bright spots in the L0 image is a red bright spot.

[0047] The calculated grayscale value difference should be considered as the absolute value after subtracting the grayscale value of the first pixel from the adjacent pixel. In this way, in dark spot detection, the minimum value of the grayscale value difference can be compared with the threshold to determine whether it belongs to a dark spot of a certain color. The second threshold used to determine whether it belongs to a bright spot of a certain color can be set according to needs.

[0048] Similarly, repeat the above steps, use the (0,255,0) image to get the G255 image to determine whether the bright spot is a green bright spot; use the (0,0,255) image to get the B255 image to determine whether the bright spot is a blue bright spot. When the bright spot belongs to three colors at the same time, it is considered a white bright spot. If it is a two-color bright spot, it is considered a two-color bright spot.

[0049] The abnormal point detection method described in the present invention can also use only a single monochrome image. If a complete classification detection of bright spots or dark spots is to be performed, it is necessary to import a map of the corresponding colors of all its pixel units. If only the bright spot / dark spot is to be determined whether it is a red bright spot / dark spot, only the monochrome image can be imported.

[0050] Furthermore, when the camera resolution and the pixel units of the display panel do not correspond one to one, such as Figure 5 shown. Figure 5 It can be seen that the camera's pixel points 2 and 5 will receive light from the two color pixel units of the display panel at the same time. Taking pixel point 2 as an example, it receives light from the red pixel unit and the green pixel unit. Therefore, when this pixel point 2 is the first pixel point, the difference between the grayscale value of pixel point 2 and the adjacent pixel points in both R255 and G255 images may be greater than the threshold. At this time, the abnormal point will be judged as a red abnormal point and a green abnormal point, that is, a two-color abnormal point.

[0051] In this embodiment, the Figure 5 This is the case where the camera resolution and the pixel unit of the display panel are misaligned in one dimension. In actual testing, misalignment in two dimensions may occur, and the actual display panel is not limited to the RGB arrangement of the LCD panel in this embodiment. Therefore, there is a possibility of multi-color abnormal points.

[0052] As another embodiment of the present invention, consider the case where multiple pixels in a camera are used to image the same pixel unit of a display panel, such as Figure 6 shown. Figure 6 The multiple pixels of the camera are used to image the pixel units of the display panel. At this time, a Mapping value can be defined to represent the ratio of the pixel points of the camera to the pixel units of the display panel, that is, m pixels to the display panel n When imaging a pixel unit, remember:

[0053]

[0054] At this time, the equivalent pixel of the camera can be obtained by conversion through the Mapping value. The Mapping value can be determined at the beginning of the test by parameters such as the camera, the display panel to be tested, and their position relationship. Therefore, for each test, the Mapping value is fixed throughout the test process.

[0055] In actual applications, the most common case is when the Mapping value is 9, which means that 9 points on the camera image one pixel unit on the display panel. Figure 6 As an example, the method of Mapping value conversion is further described here as follows: First, find the corresponding relationship between the pixel points of the camera and the pixel points of the display panel, for example Figure 6The pixel points 1-9 of the camera in the first test result image a certain pixel unit in the display panel. Then the pixel points 1-9 in the first test result and the second test result both correspond to this pixel unit in the display panel. Therefore, the first test result and the second test result are processed at the same time, and the pixel points 1-9 are merged into equivalent pixel points according to the corresponding relationship of the pixel points; after the first test result and the second test result are processed as above, the subsequent abnormal point classification step is performed with the equivalent pixel points.

[0056] In another case, if Figure 7 As shown, there may be pixels 1-9 of the camera corresponding to pixels I, II, III and IV of the display panel. Figure 7 A method for setting corresponding equivalent pixel points I, II, III and IV according to corresponding positional relationships is shown, and the average grayscale value of pixel points 1, 2, 4, and 5 is used as the grayscale value of the equivalent pixel point of pixel point I, and the average grayscale value of pixel points 2, 3, 5, and 6 is used as the grayscale value of the equivalent pixel point of pixel point II, and so on, to achieve conversion of equivalent pixel points.

[0057] Converting equivalent pixels based on Mapping values ​​is not a necessary step in the method of the present invention. Figure 7 For the case shown, the above steps S1-S3 can also be performed directly according to the grayscale values ​​of the pixels 1-9. For other cases where the Mapping value is, those skilled in the art can set the corresponding equivalent pixel conversion method according to the requirements.

[0058] The detection method used as an example in this embodiment is applied to an LCD screen with an RGB arrangement. For those skilled in the art, when the display panel to be tested is another display panel with other arrangements, such as an OLED display panel with a Pentile arrangement, a Diamond arrangement, or a Delta arrangement, the method described in the present invention can also achieve the effect of abnormal point classification by simply adjusting the corresponding parameters.

[0059] The "adjacent" pixels mentioned in the present invention, for an LCD screen with an RGB arrangement, can be pixels that overlap with the first pixel at least on one side, i.e., 4 pixels above, below, left, and right, or 8 pixels surrounding the first pixel. For screens with other arrangements, such as OLED display panels with a Pentile arrangement, a Diamond arrangement, or a Delta arrangement, the adjacent pixels can be determined based on their arrangement.

[0060] The method of the present invention is used to classify abnormal points without complicated calculation methods. By extracting the point with the largest gray value difference among the abnormal points as a representative and analyzing the color of the pixel point, the abnormal points can be effectively classified, thereby improving the efficiency of abnormal point classification.

[0061] Furthermore, it is easy for a person skilled in the art to apply the detection method described in the present invention only to a part of the display panel, or to apply the detection method described in the present invention to the local areas in sequence to complete the bright spot / dark spot detection of the entire panel. In other words, the detection method described in the present invention is not limited to testing and classifying the entire display panel, and can also be implemented by taking pictures of a local area of ​​the panel.

[0062] As another embodiment of the present invention, a device for detecting a weak abnormal point of a display panel is provided, comprising:

[0063] a camera module configured to obtain a display photo of the display panel;

[0064] A display panel control module configured to input a test pattern or a monochrome pattern to the display panel;

[0065] A calculation and analysis module is configured to obtain the shooting results of the camera and classify the abnormal points of the display panel according to the steps of any of the above methods.

[0066] As another embodiment of the present invention, there is also provided a device for detecting faint abnormal points of a display panel, which includes at least one processing unit and at least one storage unit, wherein the storage unit stores a computer program, and when the computer program is executed by the processing unit, the processing unit executes the steps of any one of the above-mentioned methods.

[0067] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the above method when executed by a processor. The computer-readable storage medium may include, but is not limited to, any type of disk, including a floppy disk, an optical disk, a DVD, a CD-ROM, a micro drive, and a magneto-optical disk, a ROM, a RAM, an EPROM, an EEPROM, a DRAM, a VRAM, a flash memory device, a magnetic card or an optical card, a nanosystem (including a molecular memory IC), or any type of medium or device suitable for storing instructions and / or data.

[0068] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting weak abnormal points of a display panel, characterized in that: include: S1. Importing the test image into the display panel, photographing the display panel as a first test result, marking the first area; Determine whether the first area is larger than one pixel, and if so, proceed to the subsequent steps; The first area is an area where the difference between the grayscale value actually captured in the first test result and the grayscale value theoretically captured in the first test result is greater than a first threshold; S2. The monochrome image is imported into the display panel, and the display panel is photographed as a second test result; S3. Mark a first pixel in the first area, mark the first pixel and its adjacent pixels in the second test result, and calculate the difference in grayscale values ​​between the first pixel and its adjacent pixels; when the minimum value of the difference in grayscale values ​​is greater than a second threshold, the point constituted by the first area is considered to be an abnormal point of the corresponding color of the monochrome image; wherein the first pixel is the pixel having the largest absolute value of the difference between the grayscale value in the first area and the average grayscale value of all pixels in the first test result.

2. The method for detecting weak abnormal points of a display panel according to claim 1, characterized in that: The monochrome image is an image composed of colors corresponding to pixel units of the display panel.

3. The method for detecting weak abnormal points of a display panel as claimed in claim 2, characterized in that: When the pixel units of the display panel are red, green and blue, the monochrome images are (255, 0, 0), (0, 255, 0) and (0, 0, 255) respectively.

4. The method for detecting weak abnormal points of a display panel as claimed in claim 3, characterized in that: S4. Replace the monochrome image, and repeat steps S2-S3 until the monochrome images of all colors are tested.

5. The method for detecting weak abnormal points of a display panel as claimed in claim 4, characterized in that: According to the test result, the points formed by the first area are one of single-color abnormal points or multi-color abnormal points.

6. The method for detecting weak abnormal points of a display panel as claimed in claim 2, characterized in that: The second threshold is set according to the pixel unit arrangement mode of the display panel and / or the test requirement.

7. The method for detecting weak abnormal points of a display panel according to claim 1, characterized in that: When the camera is used for shooting m pixels are given to the display panel n When imaging a pixel unit, after converting the actual pixel points in the first test result and the second test result into equivalent pixel points, the equivalent pixel points of the first test result and the equivalent pixel points of the second test result are used to perform steps S1-S3.

8. A device for detecting weak abnormal points of a display panel, characterized in that: include: a camera module configured to obtain a display photo of the display panel; A display panel control module configured to input a test pattern or a monochrome pattern to the display panel; A calculation and analysis module is configured to obtain the shooting results of the camera and classify the abnormal points of the display panel according to the steps of the method according to any one of claims 1 to 7.

9. A device for detecting weak abnormal points of a display panel, characterized in that: The method comprises at least one processing unit and at least one storage unit, wherein the storage unit stores a computer program, and when the computer program is executed by the processing unit, the processing unit executes the steps of the method according to any one of claims 1 to 7.

10. A storage medium, characterized in that: It stores a computer program executable by an access authentication device. When the computer program runs on the access authentication device, the access authentication device executes the steps of the method according to any one of claims 1 to 7.

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