TWI672493B - An automatic optical inspection system and method to obtain mura defect from the panel - Google Patents

Abstract

The present invention provides an optical detection system for panel speckles for detecting speckle defects (Mura) on a panel to be measured. The optical detection system includes a white light auxiliary lamp, a camera, and a processor. The white light auxiliary lamp is disposed on one side of the detection area. The white light auxiliary lamp provides a white light source to the panel to be tested. The camera is disposed on one side of the detection area, and is used for shooting the panel to be tested on the detection area to obtain a panel image of red, green or blue components. The processor is connected to the camera. The processor obtains a plurality of the panel images of the panel under test via the camera, and obtains a mura of the panel under test according to the plurality of panel images.

Description

Optical detection system and method for detecting panel streaks

The invention relates to an optical detection system and a method thereof, and more particularly to an optical detection system and a method thereof for detecting a flaw on a panel.

Automatic optical inspection is a typical method commonly used in industrial processes. Optical instruments are used to obtain the surface state of the finished product, and computer image processing technology is used to detect defects such as foreign objects or pattern abnormalities. Because it is a non-contact inspection, it can be inspected in the middle of the project. Semi-finished products.

Regarding panel inspection, the main inspection items are defects, line defects, and mura defects (such as color streaks, brightness streaks, etc.). The streak detection is generally the main basis for grading display products, which directly affects the price of the product. .

The main cause of the formation of mura defects is the lack of exposure processes. Since the size of the current LCD panel is getting larger, to complete the production of the entire panel, it is necessary to use a joint exposure method. A panel is divided into several equal parts, and the divided panel is squeezed into a mask. The seam is exposed to form a complete panel. At the junction of the seam exposure, due to the limitation of the movement accuracy of the machine, the gate metal and the source / drain metal are stacked incorrectly. Poor, so the pixels in different exposure areas have different parasitic capacitances of the thin-film transistors, which results in different coupling effects. When writing the same voltage to all pixels in this panel, it is expected to see a A uniform picture with the same gray scale, but due to the different capacitive coupling effect of each exposure area, the gray scale of each exposure area is different, so a situation of uneven brightness is formed.

At this stage, most of the speckle defects in the manufacturing process still rely on the operator to detect visually. However, whether through manual inspection or machine vision inspection, the speckle defects are difficult to be identified in the panel according to the existing technology.

An object of the present invention is to provide an optical detection system and a method thereof, which can effectively detect a mura defect on a panel by means of machine vision, and classify the panel accordingly.

In order to achieve the above object, the present invention provides a panel speckle optical detection system for detecting a speckle defect (Mura) of a panel to be tested. The optical detection system includes a white light auxiliary lamp, a camera, and a processor. The white light auxiliary lamp is disposed on one side of the detection area. The white light auxiliary lamp provides a white light source to the panel to be tested. The camera is disposed on one side of the detection area, and is used for shooting the panel to be tested on the detection area to obtain a panel image of red, green or blue components. The processor is connected to the camera. The processor obtains a plurality of the panel images of the panel under test via the camera, and obtains a mura of the panel under test according to the plurality of panel images.

Another object of the present invention is to provide an optical system for panel streaks. The detection method includes: providing a white light source disposed on one side of the detection area to illuminate the panel under test; providing a camera disposed on the side of the detection area to photograph the panel under test to obtain red and green Or blue component panel images; obtaining the plurality of panel images of the panel under test through the camera; and obtaining speckle defects of the panel under test based on the plurality of panel images.

The invention can effectively improve the detection rate of speckle defects (Mura). By analyzing the panel into different panel images, the development of the speckle defects (Mura) under different polarized light can be effectively resolved in order to address the speckle defects (Mura). Quantify different attributes and use them as a basis for classification.

The invention can also be used to detect the residual stress inside the panel or object, and perform quantitative analysis on the residual stress of the panel or object through a plurality of panel images.

100‧‧‧optical detection system

10‧‧‧Camera

11‧‧‧Camera body

12‧‧‧Polarizer

13‧‧‧ lens

20‧‧‧White light auxiliary light

30‧‧‧ processor

40‧‧‧ switchable polarizer

P‧‧‧ Panel to be tested

Z‧‧‧ Detection Area

Steps S01 to S04

Steps S41 to S42

Steps S05 to S06

FIG. 1 is a schematic diagram of an appearance of an optical detection system according to the present invention.

FIG. 2 is a schematic block diagram of an optical detection system according to the present invention.

FIG. 3 is a schematic diagram showing a relationship between a polarization angle and a color light image.

Figure 4. Schematic image of quantitative analysis.

FIG. 5 is a schematic diagram of an appearance of another embodiment of the present invention.

FIG. 6 is a schematic flow chart (1) of the optical detection method of the present invention.

FIG. 7 is a schematic flow chart (2) of the optical detection method of the present invention.

FIG. 8 is a schematic flow chart of the optical detection method of the present invention (3)

The detailed description and technical contents of the present invention are described below with reference to the drawings. Furthermore, the drawings in the present invention are for convenience of explanation, and their proportions are not necessarily drawn according to actual proportions. These drawings and their proportions are not intended to limit the scope of the present invention, and will be described here in advance.

As used herein, "comprising or including" means not excluding the presence or addition of one or more other components, steps, operations, and / or elements to the recited components, steps, operations, and / or elements. "About or close to" or "essentially" means having a value or range close to the allowable specified error to avoid being used by any unreasonable third party, illegal or unfair, to understand the precise or absolute value disclosed in the present invention. "One" means that the grammatical object of the thing is one or more (that is, at least one).

The following is a description of a preferred embodiment of the present invention. Please refer to "Figure 1" and "Figure 2" together, which are schematic diagrams and block diagrams of the first embodiment of the present invention, as shown in the figure: The embodiment provides an optical detection system 100 for panel speckles for detecting a speckle defect (Mura) of the panel P to be tested. The optical detection system 100 includes a white light auxiliary lamp 20, a camera 10, and a processor 30 connected to the camera 10 and the white light auxiliary lamp 20.

The white-light auxiliary lamp 20 is disposed on one side of the detection area Z. The white light auxiliary lamp 20 provides a white light source to the panel P to be tested. The “side” referred to herein means that the white light source of the white-light auxiliary lamp 20 can be irradiated to any position of the panel P to be tested and form an irradiation surface, such as front, back, side, side, and panel P to be tested. There is an inclination angle or the like between the surfaces, which is not limited in the present invention. In a preferred embodiment, the white light auxiliary lamp 20 is a side light, a backlight, a ring light, or other light sources, and is not limited in the present invention.

The camera 10 is disposed on one side of the detection area Z, and is used to capture the panel P to be tested on the detection area Z to obtain a panel image with red, green or blue components. In a preferred embodiment, the camera 10 includes a polarized light camera or a full-color camera. The polarized light camera such as a linear polarized light camera (Line Scan) or an area polarized light camera (Area Scan) can be selected according to the application. In the present invention, it is only for illustration, and is not intended to limit the present invention. The polarized light camera passes one or a plurality of polarizers with different phase angles to obtain a red light (RED), green light (GREEN), blue light (BLUE) image, or a mixed light (MIX) panel image. The “side” referred to here does not refer to a specific side of the detection area Z. For example, the positions where the detection area Z where the panel P to be tested can fall within the image capturing range of the camera 10 belong to the “ "Side" in the context of the text, here in advance.

The processor 30 is connected to the camera 10 and the white-light auxiliary lamp 20 to control the operations of the devices. In a preferred embodiment, the processor 30 works in cooperation with the storage unit to access the data of the storage unit and execute a program pre-stored in the storage unit. It must be explained here that the processor and the storage unit described in the present invention are not limited to a single one, and when necessary, a plurality of processors and a plurality of storage units may be used to execute programs and complete work cooperatively. In another preferred embodiment, the processor 30 may be co-constructed with the storage unit. The processor 30 is, for example, a Central Processing Unit (CPU), or other programmable General purpose or special purpose microprocessor (Microprocessor), digital signal processor (DSP), programmable controller, application specific integrated circuits (ASIC), programmable Programmable Logic Device (PLD) or other similar devices or a combination of these devices.

In an embodiment in which the camera 10 is a polarized light camera, the main structure of the camera 10 includes a polarizer 12 and a lens 13 corresponding to the polarizer 12 in addition to the camera body 11. The lens 13 can split and collimate the passing beam, so that the beam can enter the polarizer 12 through a specific angle, and after filtering the beam of a special wavelength through the polarizer 12, the sensor chip of the camera body 11 can obtain image data. . Through the design of the light path, the camera 10 can obtain three types of polarized images or full-color images of the entire panel P to be tested in one shot, reducing the number of station settings.

According to Malus' law, when polarized light is irradiated on a polarizer, the irradiance I of the transmitted light is as follows: I = I ₀ cos θ _i ; where I ₀ is the irradiance of the incident light, θ _i = θ ₁ -θ ₀ is the angle between the polarization direction and the transmission axis of the polarizer.

It can be known from the above formula that different polarization directions can be obtained through different polarization angles, and each image is analyzed separately. Some special wavelength beams can better reflect some special defects. By providing polarizers with different angles, Individually quantify images with different polarization angles.

As shown in Figure 3, when the polarization angle is 0 degrees, the image output by the polarization camera is red light, when the polarization angle is 90 degrees, the image output by the polarization camera is blue light, and when the polarization angle is 135 degrees, the polarization camera The output image is a green light image. Quantitative analysis can be performed based on the chromaticity or gray scale of three different color light images, and the degree of speckle defects in the image can be judged based on the three different chromaticities, thereby detecting defects of excellent streaks or bright streaks.

In addition to detecting speckle defects, the camera 10 can also perform qualitative residual stress analysis and quantitative analysis of the relative polarization angle difference of the sample. Quantitative analysis can determine the relative polarization angle change of the panel P to be tested at any position by different RGB color level changes. It is also possible to know the internal residual stress of the object to be tested by the fringe density of different color levels, such as As shown in Figure 4, the dashed boxed areas: the higher the density of the stripes of different color levels in a unit area, the greater the internal residual stress. The solid boxed areas: the relative polarization angle difference in this area is about 90 °, There are also residual stresses. For birefringent media materials, plastics, glass and other materials with polarization characteristics, it can have more accurate measurement of polarization characteristics.

Please refer to FIG. 5 together, which is a schematic diagram showing the appearance of another embodiment of the present invention, as shown in the figure: In a preferred embodiment, the light beam output by the white light auxiliary lamp 20 can be passed through the polarizer 12 in advance. The colored light filtered to a special wavelength illuminates the panel P to be tested, so as to further enhance the polarization of the camera 10 under different colored light images. As shown in FIG. 4, a switchable polarizer 40 is disposed between the white light auxiliary lamp 20 and the detection area Z. The processor 30 (as shown in FIG. 3) switches the switching polarizer 40 Angle to output the corresponding light source.

Please refer to FIG. 6 together, a schematic flowchart (1) of the optical detection method of the present invention. The present invention provides the following methods to obtain the speckle defects of the panel P to be tested. The method includes providing a white light source disposed on one side of the detection area Z to illuminate the panel P to be measured (step S01); providing a camera 10 disposed on the side of the detection area Z to photograph the panel to be measured P to obtain a panel image of red, green or blue components (step S02), wherein the camera 10 is provided, for example, a polarized light camera or a full-color camera, and a plurality of the panel images of the panel P to be tested are obtained through the camera 10 The steps include switching the polarizer angle to obtain a red (GRE), green (GREEN), blue (BLUE) image, or a mixed light (MIX) panel image; obtaining the panel P to be tested through the camera 10 A plurality of panel images (step S03); obtaining a speckle defect of the panel P to be tested according to the plurality of panel images (step S04).

Please refer to FIG. 7 together, a schematic flowchart of the optical detection method of the present invention (2). Wherein, in step S04, the processor 30 performs the following method on the panel P to be tested to obtain the speckle defect, the method includes: performing a quantitative analysis on each of the panel images (step S41); and according to the quantification The result of the analysis confirms that the relative polarization angle of the individual position of the panel P to be measured changes (step S42).

Please refer to FIG. 8 together, a schematic flowchart of the optical detection method of the present invention (3). In addition to obtaining speckle defects, the present invention provides a method for obtaining the residual stress of the panel P to be tested, the method comprising: individually obtaining a stripe density distribution in the panel image based on a plurality of the panel images (step S05); and The fringe density distribution confirms the residual stress distribution inside the panel P to be measured (step S06). Residue The stress is expressed differently in the direction of the stress and under different polarized light. Through the fringe density distribution, the degree and directivity of the residual stress can be known.

In addition, the method of the present invention may further provide a switchable polarizer between the white light auxiliary lamp 20 and the detection area Z, and switch the angle of the switchable polarizer corresponding to the polarizer on the camera 10 to output a corresponding Light source to the panel P to be tested.

In summary, the present invention can effectively improve the detection rate of speckle defects (Mura). By analyzing the panel into different panel images, the development of the speckle defects (Mura) under different polarized light can be effectively resolved. Speckle defects (Mura) are quantified for different attributes and used as a basis for classification. In addition, the present invention can also be used to detect the residual stress inside a panel or an object, and perform a quantitative analysis on the residual stress of a panel or an object through a plurality of panel images.

The present invention has been described in detail above, but the above is only a preferred embodiment of the present invention. When the scope of implementation of the present invention cannot be limited in this way, that is, the equality made in accordance with the scope of patent application of the present invention Changes and modifications should still be covered by the patent of the present invention.

Claims (11)

An optical detection system for detecting a panel's speckle is used to detect a speckle defect (Mura) of the panel to be tested. The optical detection system includes: a white light auxiliary lamp, which is arranged at one side of the detection area, and the white light auxiliary lamp A white light source onto the panel to be tested; a camera disposed on one side of the detection area to capture the panel under test on the detection area to obtain a panel image of red, green or blue components; and A processor is connected to the camera, and the processor obtains a plurality of the panel images of the panel under test through the camera, and obtains a mura of the panel under test according to the plurality of panel images, and The plurality of panel images are individually subjected to quantitative analysis, and the relative polarization angle changes of individual positions of the panel under test are confirmed according to the results of the quantitative analysis. The optical detection system according to item 1 of the patent application scope, wherein the camera comprises a polarized light camera or a full-color camera. The optical detection system according to item 2 of the patent application scope, wherein the polarized light camera is a linear polarized light camera or a surface polarized light camera. The optical detection system according to item 3 of the patent application scope, wherein the processor switches the polarizer angle to obtain red light (GRE), green light (GREEN), and blue light, respectively. (BLUE) image, or mixed light (MIX) panel image. The optical detection system according to item 1 of the patent application scope, wherein the white light auxiliary lamp is a side lamp, a backlight, or a ring lamp. The optical detection system according to item 1 of the patent application scope, wherein a switching polarizer is disposed between the white light auxiliary lamp and the detection area, and the processor switches the angle of the switching polarizer to output a corresponding light source. . An optical detection method for detecting a panel wrinkle includes: providing a white light source disposed on one side of a detection area to illuminate the panel to be measured; and providing a camera disposed on one side of the detection area to photograph the The panel under test on the detection area to obtain panel images of red, green, or blue components; the plurality of panel images of the panel under test are obtained through the camera; and the speckle of the panel under test is obtained based on the plurality of panel images A defect; and performing a quantitative analysis individually based on the plurality of panel images, and confirming a change in the relative polarization angle of the individual positions of the panel under test based on the results of the quantitative analysis. The optical detection method according to item 7 of the patent application scope, wherein providing the camera includes providing a polarized light camera or a full-color camera. The optical detection method according to item 8 of the scope of patent application, wherein the photography is transmitted through The step of obtaining the plurality of panel images of the panel under test by the camera includes obtaining a red (RED), green (GREEN), blue (BLUE) image, or a mixed light (MIX) panel image by switching the polarizer angles. . The optical detection method according to item 8 of the scope of patent application, further comprising: individually obtaining a fringe density distribution in the panel image based on the plurality of panel images; and confirming a residual stress distribution in the panel under test based on the fringe density distribution. . The optical detection method according to item 7 of the patent application scope includes: providing a switching polarizer between the white light auxiliary lamp and the detection area; and switching the angle of the switching polarizer in response to the polarizer on the camera To output the corresponding light source to the panel under test.