A method and device for detecting internal contamination of a fully transparent color film LCD

Abstract

The present invention discloses a method and device for detecting internal dirt of a fully transparent color film LCD, the method comprising the following steps: step S1, placing an LCD product to be detected on a detection platform; step S2, an industrial camera collects three images of grayscale of the image display area under different color backlight sources based on the same exposure time, and an image processing module determines the main color tone of the LCD product according to the grayscale of the collected image display area; step S3, and uses the image collected under the light source corresponding to the main color tone as the main image, and the images collected under the other two light sources as auxiliary images; step S4, in the image collected by the main color backlight source, if the LCD product has internal dirt, the area where the internal dirt is located will appear black, and in the other two auxiliary images, if the LCD product has internal dirt, the area where the internal dirt is located will appear white, thereby completing the internal dirt detection of the fully transparent color film LCD. The present invention can efficiently and stably realize the detection of poor internal dirt of color film LCD products, and accurately distinguish it from surface dirt, and better meet the process requirements.

Description

Technical Field

[0001] The invention relates to a method for detecting optical defects of LCD products, and in particular to a method and a device for detecting internal contamination of a full-transparent color film LCD. Background Art

[0002] Among the existing display products, LCD products can be divided into reflective type, fully transparent type, and semi-transparent type. Fully transparent color film LCD is a type of fully transparent LCD product. The orientation of the liquid crystal molecules in different directions in the liquid crystal box matches the fixed polarizer angle to present different film colors. The production process of LCD products requires multiple processes. Due to the differences in the level of technology, LCDs will inevitably form defects during the production process. In the prior art, stains in the liquid crystal box are a common defect that will destroy the structure of liquid crystal molecules and cause display abnormalities. It is an intolerable defect type and should be selected as defective products during the screening process and no missed detection is allowed. The current defect detection method is mainly manual, but the manual detection method has low production efficiency, and long-term work can easily cause eye fatigue and affect the detection results. Although the method of relying on machine vision can realize the automated defect detection process, it is difficult to distinguish between stains on the protective film of the polarizer on the LCD surface and stains inside the LCD. It is easy to misjudge the dirt on the protective film as defective, which leads to missed detection or misjudgment. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method and device for detecting internal stains of a full-transparent color film LCD, which can accurately detect internal stains of LCD products and improve the accuracy and work efficiency of LCD product defect detection, in view of the shortcomings of the prior art.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0005] A method for detecting internal contamination of a fully transparent color film LCD is implemented based on a device. The device comprises an image processing module, an industrial camera, a color backlight source and a detection platform. The color backlight source is located below the detection platform, the industrial camera is located above the detection platform, and image data captured by the industrial camera is transmitted to the image processing module. The method comprises the following steps: step S1, placing an LCD product to be detected on the detection platform; step S2, the industrial camera collects three images of grayscale of a display area under different color backlight sources based on the same exposure time, and the image processing module determines the main color tone of the LCD product according to the grayscale of the collected image display area; step S3, and taking the image collected under the light source corresponding to the main color tone as the main image, and the images collected under the other two light sources as auxiliary images; step S4, in the image collected by the main color backlight source, if the LCD product has internal contamination, the area where the internal contamination is located will appear black, and if the LCD product has internal contamination in the other two auxiliary images, the area where the internal contamination is located will appear white, thereby completing the internal contamination detection of the fully transparent color film LCD.

[0006] Preferably, in step S2, the color backlight source is first controlled to emit green light and the industrial camera captures images, the camera exposure time is adjusted, and under the recorded camera exposure time conditions, the color backlight source is respectively controlled to emit red light and blue light, and the industrial camera captures two corresponding images.

[0007] Preferably, in step S2, after adjusting the camera exposure time, the grayscale value range of the image background is limited to between 180 and 220.

[0008] Preferably, the image processing module includes a main color tone analysis module and an internal contamination detection module.

[0009] Preferably, in step S2, the main color tone analysis module compares the grayscale values ​​of the display areas of the three images under the same exposure time, and identifies the light source color corresponding to the image with the largest grayscale value of the display area as the main color tone of the LCD product.

[0010] Preferably, in step S3, after obtaining the main color tone of the LCD product film color, the grayscale interval of the display area is set to 80 to 100, the camera exposure time is adjusted, and the industrial camera is used to capture images under red, green and blue light sources.

[0011] A fully transparent color film LCD internal contamination detection device, the device comprises an image processing module, an industrial camera, a color backlight source and a detection platform, the color backlight source is located below the detection platform, the industrial camera is located above the detection platform, the image data captured by the industrial camera is transmitted to the image processing module, and the device is used to execute the above method.

[0012] Preferably, a light source controller is included, and the light source controller is connected between the image processing module and the color backlight source.

[0013] Preferably, a transparent glass plate for placing the LCD product to be inspected is provided on the top of the inspection platform.

[0014] Preferably, the lens of the industrial camera is aimed at the transparent glass plate.

[0015] In the fully transparent color film LCD internal dirt detection method disclosed in the present invention, three images of a color backlight source under three different colors of illumination, namely red light, green light and blue light, are obtained, and the three images are analyzed based on a color film main color tone analysis algorithm to obtain the main color tone of the LCD product, and the image collected under the light source corresponding to the main color tone is used as the main image, and the images collected under the other two light sources are used as auxiliary images. In the specific detection process, by comparing whether there is a different color area in the same area of ​​the main image and the auxiliary image: that is, the main image area is darker than the background color, and the auxiliary image area is whiter than the background color. At the same time, because the dirt on the protective film is darker than the background color in both the main image and the auxiliary image, the internal stains of the LCD product can be accurately detected, which can effectively improve the accuracy of LCD product defect detection. Compared with the prior art, the present invention can efficiently and stably realize the detection of poor internal dirt of color film type LCD products, and accurately distinguish it from surface dirt, which better meets the process requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a block diagram of the internal dirt detection device of the full-transparent color film LCD;

[0017] Figure 2 This is a schematic diagram of the structure of a fully transparent color film LCD internal contamination detection device;

[0018] Figure 3 It is a schematic diagram of the main figure in the internal dirt detection method of the full-transparent color film LCD of the present invention;

[0019] Figure 4 The invention provides an auxiliary device for the method for detecting internal dirt in a fully transparent color film LCD. Figure 1 Schematic diagram;

[0020] Figure 5 The invention provides an auxiliary device for the method for detecting internal dirt in a fully transparent color film LCD. Figure 2 Schematic diagram. DETAILED DESCRIPTION

[0021] The present invention is described in more detail below with reference to the accompanying drawings and embodiments.

[0022] The present invention discloses a method for detecting internal dirt in a fully transparent color film LCD. Figure 1 and Figure 2The method is implemented based on a device, the device includes an image processing module 1, an industrial camera 2, a color backlight source 3 and a detection platform 4, the color backlight source 3 is located below the detection platform 4, the industrial camera 2 is located above the detection platform 4, and the image data captured by the industrial camera 2 is transmitted to the image processing module 1. The method includes the following steps:

[0023] Step S1, placing the LCD product to be tested on the testing platform 4;

[0024] Step S2, the industrial camera 2 collects three images of grayscale display areas under different color backlight sources based on the same exposure time, and the image processing module 1 determines the main color tone of the LCD product according to the collected image display area grayscale;

[0025] Step S3, taking the image captured under the light source corresponding to the main color tone as the main image, and the images captured under the other two light sources as auxiliary images;

[0026] Step S4: In the image captured by the main color backlight source, if the LCD product has internal dirt, the area where the internal dirt is located will appear black. If the LCD product has internal dirt in the other two auxiliary images, the area where the internal dirt is located will appear white, thereby completing the internal dirt detection of the full-transparent color film LCD.

[0027] In the above method, three images of the color backlight source under three different colors of light, red light, green light and blue light, are obtained, and the three images are analyzed based on the color film main color analysis algorithm to obtain the main color of the LCD product, and the image collected under the light source corresponding to the main color is used as the main image, and the images collected under the other two light sources are used as auxiliary images. In the specific detection process, by comparing whether there is a different color area in the same area of ​​the main image and the auxiliary image: that is, the main image area is darker than the background color, and the auxiliary image area is whiter than the background color. At the same time, because the dirt on the protective film is darker than the background color in both the main image and the auxiliary image, the internal stains of the LCD product can be accurately detected, which can effectively improve the accuracy of LCD product defect detection. Compared with the prior art, the present invention can efficiently and stably realize the detection of internal contamination of color film LCD products, and accurately distinguish it from surface dirt, which better meets the process requirements.

[0028] As a preferred embodiment, the image processing module 1 includes a main color tone analysis module 10 and an internal contamination detection module 11 .

[0029] Before detection and analysis, this embodiment should first be identified as the main color of the LCD product. To this end, in step S2, the color backlight source 3 is first controlled to emit a green light source and the industrial camera 2 captures an image, and the camera exposure time is adjusted. Under the recorded camera exposure time conditions, the color backlight source 3 is respectively controlled to emit red light and blue light, and the industrial camera 2 captures two images accordingly. Furthermore, in step S2, after adjusting the camera exposure time, the image background grayscale value range is limited to between 180 and 220.

[0030] On this basis, in step S2, the main color tone analysis module 10 compares the display area grayscales of the three images under the same exposure time, and identifies the light source color corresponding to the image with the largest display area grayscale value as the main color tone of the LCD product.

[0031] In a preferred embodiment of the present invention, the principle of identifying the main color tone of an LCD product is as follows: a fully transparent LCD to be inspected is placed on a detection platform, a colored backlight source is controlled to emit green light to capture an image, the camera exposure time is adjusted, and the image background grayscale value range is limited to between 180 and 220 to prevent the overall image from being overexposed, the current camera exposure time is recorded, and at the obtained camera exposure time, the colored backlight source is controlled to emit red light and blue light to capture two images simultaneously, and the grayscale of the display area of ​​three images captured under different color backlight sources at the same exposure time is further compared, where the light source color corresponding to the image with the largest grayscale value in the display area is the main color tone of the LCD.

[0032] In the specific detection process, in step S3, after obtaining the main color tone of the LCD product film color, the grayscale range of the display area is set to 80 to 100, the camera exposure time is adjusted, and the industrial camera 2 captures images under red, green and blue light sources.

[0033] Specifically, after obtaining the main color tone of the LCD product film color, this embodiment sets the grayscale interval of the display area between 80 and 100, and then adjusts the camera exposure time to obtain images under the illumination of red, green and blue light sources. In the image captured by the main color tone backlight source, the liquid crystal molecules in the liquid crystal box have a high transmittance to the current light source. If there is internal pollution in the liquid crystal box, the orientation of the liquid crystal molecules in the liquid crystal box will be destroyed, and the area where the internal pollution is located will appear black. In the images captured by the other two light sources, the liquid crystal in the liquid crystal box has an inhibitory effect on the transmittance of the current light source. If there is internal pollution, the orientation of the liquid crystal molecules will be destroyed, and the inhibitory effect on the transmittance of the current light source will be reduced, and the area where the internal pollution is located will appear white. Based on this principle, the present invention uses the color backlight image corresponding to the main color tone of the color film as the main image, and the other two images as auxiliary images. The area where the internal pollution is located in the main image is black, and the area where it is located in the other two auxiliary images is white. The image presentation effect of the internal pollution under different light sources is as follows: Figures 3 to 5As shown, in addition, the dirt on the glass surface will not destroy the analysis orientation inside the liquid crystal box, and it is black in all three images. Accordingly, the present invention can stably detect poor internal dirt in color film LCD products based on the above detection method, and stably distinguish it from surface dirt, with higher detection accuracy.

[0034] On this basis, this embodiment also proposes a fully transparent color film LCD internal contamination detection device, characterized in that the device includes an image processing module 1, an industrial camera 2, a color backlight source 3 and a detection platform 4, the color backlight source 3 is located below the detection platform 4, the industrial camera 2 is located above the detection platform 4, the image data captured by the industrial camera 2 is transmitted to the image processing module 1, and the device is used to execute the above method.

[0035] See also Figure 1 This embodiment includes a light source controller 5, which is connected between the image processing module 1 and the color backlight source 3. Figure 2 The top of the inspection platform 4 is provided with a transparent glass plate 6 for placing the LCD product to be inspected. Further, the lens 7 of the industrial camera 2 is aimed at the transparent glass plate 6.

[0036] The invention discloses a method and device for detecting internal dirt of a fully transparent color film LCD, which realizes stable and rapid detection of internal dirt of a fully transparent color film LCD, effectively improves the detection effect of defective products, and can reduce the misjudgment of dirt on the protective film. In practical applications, the detection accuracy of internal dirt of LCD is higher.

[0037] 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 or improvements made within the technical scope of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for detecting internal contamination of a fully transparent color film LCD, characterized in that: The method is implemented based on a device, which includes an image processing module, an industrial camera, a color backlight source and a detection platform, wherein the color backlight source is located below the detection platform, the industrial camera is located above the detection platform, and the image data captured by the industrial camera is transmitted to the image processing module, and the image processing module includes a main color analysis module and an internal contamination detection module; The method comprises the following steps: Step S1, placing the LCD product to be tested on the testing platform; Step S2, the industrial camera collects three images of grayscale display areas under different color backlight sources based on the same exposure time, and the image processing module determines the main color tone of the LCD product according to the collected image display area grayscale; Step S3, taking the image captured under the light source corresponding to the main color tone as the main image, and the images captured under the other two light sources as auxiliary images; Step S4, in the image captured by the main color backlight source, if the LCD product has internal dirt, the area where the internal dirt is located will appear black, and if the LCD product has internal dirt in the other two auxiliary images, the area where the internal dirt is located will appear white, thereby completing the internal dirt detection of the full-transparent color film LCD; In step S2, the color backlight source is controlled to emit green light to capture images, the camera exposure time is adjusted, the image background grayscale value range is limited to between 180 and 220 to prevent the overall image from being overexposed, the current camera exposure time is recorded, and under the obtained camera exposure time, the color backlight source is controlled to emit red light and blue light to capture two images at the same time, and the grayscale of the display area of ​​three images captured under different color backlight sources at the same exposure time is further compared, where the light source color corresponding to the image with the largest grayscale value in the display area is the main color tone of the LCD; In step S3, after obtaining the main color tone of the LCD product film color, the grayscale interval of the display area is set to 80 to 100, the camera exposure time is adjusted, and the industrial camera is used to capture images under the illumination of red, green and blue light sources.

2. A fully transparent color film LCD internal contamination detection device, characterized in that: The device includes an image processing module, an industrial camera, a color backlight source and a detection platform, wherein the color backlight source is located below the detection platform, and the industrial camera is located above the detection platform. Image data captured by the industrial camera is transmitted to the image processing module, and the image processing module includes a main color analysis module and an internal contamination detection module. The device is used to execute the method described in claim 1.

3. The fully transparent color film LCD internal contamination detection device as claimed in claim 2, characterized in that: A light source controller is included, and the light source controller is connected between the image processing module and the color backlight source.

4. The fully transparent color film LCD internal dirt detection device as claimed in claim 2, characterized in that: A transparent glass plate for placing the LCD product to be inspected is provided on the top of the inspection platform.

5. The fully transparent color film LCD internal contamination detection device as claimed in claim 4, characterized in that: The lens of the industrial camera is aimed at the transparent glass plate.

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