KR102584696B1 - Method for optical inspection of display panel - Google Patents

Abstract

In an optical inspection method of a display panel, an image including a first area, a second area surrounding the first area, and a third area surrounding the second area can be obtained by photographing the display panel. Periodically arranged unit patterns can be extracted from the first and second areas of the image. Virtual patterns created using unit patterns can be attached to the third area. Each of the unit patterns can be compared with the unit patterns and/or virtual patterns surrounding it. It is possible to determine whether a defect exists in each of the unit patterns, and if a defect exists, location information about the defect can be obtained.

Description

Optical inspection method of display panel {METHOD FOR OPTICAL INSPECTION OF DISPLAY PANEL}

The present invention relates to an optical inspection method. More specifically, the present invention relates to an automatic optical inspection method of a display panel.

Flat panel display devices are used as display devices to replace cathode ray tube displays due to their characteristics such as light weight and thinness. Representative examples of such flat panel displays include liquid crystal display (LCD) devices and organic light emitting display (OLED) devices. During the manufacturing process of such flat display devices, defects may occur in the display panel.

The inspector can determine the presence and location of defects in the display panel with the naked eye. However, when an inspector visually inspects a display panel, the inspection time is determined depending on the inspector's condition, and because the inspection standards are different for each inspector, there is a problem in that the quality of the display panel is not maintained uniformly. Additionally, visual inspection has the disadvantage of taking a long time.

The purpose of the present invention is to provide an optical inspection method for a display panel that can automatically identify defects in the display panel and expand the inspection area of the display panel.

However, the purpose of the present invention is not limited to these purposes, and may be expanded in various ways without departing from the spirit and scope of the present invention.

In order to achieve the above-described object of the present invention, according to an optical inspection method of a display panel according to some exemplary embodiments, a display panel is photographed to form a first area, a second area surrounding the first area, and the An image including a third area surrounding the second area may be obtained. Periodically arranged unit patterns may be extracted from the first area and the second area of the image. Virtual patterns created using the unit patterns can be attached to the third area. Each of the unit patterns may be compared with the unit patterns and/or the virtual patterns surrounding it. It is possible to determine whether a defect exists in each of the unit patterns, and if a defect exists, location information about the defect can be obtained.

In example embodiments, the display panel may include a display area including a central area and an edge area, and a peripheral area surrounding the display area. The first area may correspond to the central area, the second area may correspond to the edge area, and the third area may correspond to the peripheral area.

In example embodiments, the virtual patterns may be created using the unit patterns of the second area.

In example embodiments, each of the unit patterns in the first area may be compared with the unit patterns in the first area and/or the second area surrounding it. Each of the unit patterns of the second area may be compared with the unit patterns of the first and second areas surrounding the unit patterns, and the virtual patterns of the third area.

In example embodiments, each of the unit patterns may be compared with the eight unit patterns and/or the virtual patterns surrounding it.

In example embodiments, each of the unit patterns and the virtual patterns may include pixel patterns corresponding to pixels included in the display panel.

In example embodiments, when comparing each of the unit patterns with the unit patterns and/or the virtual patterns surrounding them, the pixel pattern included in each of the unit patterns and the virtual patterns Among them, corresponding pixel patterns can be compared.

In example embodiments, when comparing the corresponding pixel patterns, grayscale values of the corresponding pixel patterns may be compared.

In order to achieve the above-described object of the present invention, according to an optical inspection method of a display panel according to other exemplary embodiments, a display panel is photographed to form a first area, a second area surrounding the first area, and the An image including a third area surrounding the second area may be obtained. Periodically arranged unit patterns may be extracted from the first area and the second area of the image. Each of the unit patterns in the first area may be compared with the unit patterns surrounding it. Each of the unit patterns in the second area may be compared with the unit patterns in the second area adjacent thereto. It is possible to determine whether a defect exists in each of the unit patterns, and if a defect exists, location information about the defect can be obtained.

In example embodiments, the display panel may include a display area including a central area and an edge area, and a peripheral area surrounding the display area. The first area may correspond to the central area, the second area may correspond to the edge area, and the third area may correspond to the peripheral area.

In example embodiments, each of the unit patterns in the first region may be compared with eight unit patterns surrounding it.

In example embodiments, each of the unit patterns in the second area may be compared with two adjacent unit patterns.

In example embodiments, each of the unit patterns may include pixel patterns corresponding to pixels included in the display panel.

In example embodiments, each of the unit patterns in the first area is compared with the unit patterns surrounding it, and each of the unit patterns in the second area is compared to the unit patterns in the second area adjacent thereto. When comparing unit patterns, corresponding pixel patterns among the pixel patterns included in each of the unit patterns may be compared.

In example embodiments, when comparing the corresponding pixel patterns, grayscale values of the corresponding pixel patterns may be compared.

According to an optical inspection method of a display panel according to some exemplary embodiments of the present invention, virtual patterns are attached to the third area, and unit patterns of the second area are each formed into units of the first area and the second area surrounding the unit patterns. By comparing the patterns and the virtual patterns of the third area, the inspection area of the display panel can be expanded. In addition, according to the optical inspection method of the display panel according to other exemplary embodiments of the present invention, each of the unit patterns of the second area is compared with the unit patterns of the second area adjacent thereto, so that the inspection area of the display panel can be expanded.

However, the effects of the present invention are not limited to the effects described above, and may be expanded in various ways without departing from the spirit and scope of the present invention.

1 is a diagram illustrating a display panel inspected by an optical inspection method of a display panel according to exemplary embodiments of the present invention.
2 is a flowchart showing a method for optically inspecting a display panel according to exemplary embodiments of the present invention.
FIG. 3 is a diagram showing an image acquired through the step of acquiring the image of FIG. 2.
FIG. 4 is a flow chart illustrating an example of comparing each of the unit patterns of FIG. 2 with adjacent unit patterns.
FIG. 5 is a diagram showing an image obtained by attaching the virtual patterns of FIG. 4 to the third area.
FIG. 6 is a diagram illustrating a comparison method comprising comparing each of the unit patterns of FIG. 4 with unit patterns and/or virtual patterns surrounding them.
FIG. 7 is a flow chart illustrating another example of comparing each of the unit patterns of FIG. 2 with adjacent unit patterns.
FIG. 8 is a diagram showing a comparison method using the steps of FIG. 7.

Hereinafter, optical inspection methods of a display panel according to exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The same or similar reference numerals are used for identical components in the drawings.

1 is a diagram illustrating a display panel inspected by an optical inspection method of a display panel according to exemplary embodiments of the present invention.

Referring to FIG. 1 , the display panel 100 may include a display area 110 and a peripheral area 120 adjacent to the display area 110 . In example embodiments, the display area 110 may be located in the center of the display panel 100, and the peripheral area 120 may surround the display area 110. For example, the display panel 100 may be a panel for an organic light emitting display device or a panel for a liquid crystal display device.

Pixels 130 may be arranged in the display area 110. For example, the pixels 130 may be arranged in a first direction and a second direction substantially orthogonal to the first direction. In the display area 110, an image that is a collection of lights emitted from the pixels 130 may be displayed. The display area 110 may be divided into a central area 112 located in the center of the display area 110 and an edge area 114 surrounding the central area 112.

A driver 140, a fan-out unit 150, etc. for driving the pixels 130 may be disposed in the peripheral area 120. For example, the driver 140 may be disposed in an area of the peripheral area 120 adjacent to the display area 110 in the first direction and/or in a direction opposite to the first direction, and the fan-out unit ( 150 may be disposed in an area of the peripheral area 120 adjacent to the display area 110 in the second direction.

During the manufacturing process of the display panel 100, a patterning process of depositing, etching, and cleaning thin films such as insulating films and conductive films disposed on the substrate may be performed. In this case, defects may occur in the display panel 100 during the patterning process. Additionally, during the manufacturing process of the display panel 100, foreign substances may enter the display panel 100 from the outside, causing defects in the display panel 100.

In order to detect such defects in the display panel 100, an inspection process may be performed during the manufacturing process of the display panel 100 or after completion of manufacturing. For example, this inspection process may include an optical inspection method that irradiates light to the display panel 100 and inspects the display panel 100 using reflected light. In particular, when performing an automatic optical inspection (AOI) method, defects in the display panel 100 can be automatically identified.

2 is a flowchart showing a method for optically inspecting a display panel according to exemplary embodiments of the present invention.

Referring to FIG. 2, in the optical inspection method of a display panel according to exemplary embodiments of the present invention, an image can be obtained by photographing the display panel (S100), and unit patterns arranged periodically from the image are obtained. Can be extracted (S200). Each of the unit patterns can be compared with the unit patterns adjacent to it (S300), it can be determined whether a defect exists in each of the unit patterns, and if a defect exists, location information of the defect can be obtained. (S400).

FIG. 3 is a diagram showing an image acquired through the step of acquiring the image of FIG. 2.

Referring to FIG. 3, an image 200 can be obtained by photographing the display panel 100 (S100). For example, the image 200 may be obtained by irradiating light to the display panel 100 using a light source and collecting light reflected from the display panel 100 using a camera. Accordingly, instead of directly inspecting the display panel 100 to identify defects, the display panel 100 can be inspected indirectly using the image 200 taken of the display panel 100.

The image 200 may include a first area 212, a second area 214, and a third area 220. The first area 212 may be located in the center of the image 200, the second area 214 may surround the first area 212, and the third area 220 may be located in the center of the image 200. ) can be surrounded. In example embodiments, the first area 212 may correspond to the central area 112 of the display panel 100, and the second area 214 may correspond to the edge area 114 of the display panel 100. may correspond to , and the third area 220 may correspond to the peripheral area 120 of the display panel 100.

Afterwards, periodically arranged unit patterns 210 can be extracted from the image 200 (S200). By analyzing the image 200, shapes that are regularly arranged on the display panel 100 can be extracted, and the shapes can be defined as unit patterns 210. In example embodiments, the image 200 may display pixel patterns 230 corresponding to the pixels 130 arranged in the display area 110 of the display panel 100, and a certain number of The pixel patterns 230 may be defined as one unit pattern 210. Accordingly, each of the first region 212 and the second region 214 may include unit patterns 210 . In FIG. 3, each unit pattern 210 is illustrated as including six pixel patterns 230, but the present invention is not limited thereto, and each unit pattern 210 can include any number of pixel patterns 230. ) may include. Additionally, since there are no regularly arranged shapes such as pixels 130 in the peripheral area 120 of the display panel 100, the third area 220 may not include unit patterns 210. .

Thereafter, each of the unit patterns 210 of the first region 212 and the second region 214 may be compared with the unit patterns 210 adjacent thereto (S300). In example embodiments, corresponding pixel patterns 230 among the pixel patterns 230 included in the unit patterns 210 may be compared. For example, as shown in FIG. 3, each of the unit patterns 210 may include six pixel patterns 230 consisting of two pixel rows and three pixel columns. In this case, corresponding pixel patterns 230 located at the same position within each unit pattern 210 can be compared.

In example embodiments, grayscale values of pixel patterns 230 corresponding to the unit patterns 210 may be compared. If there is a defect in the pixel 130, the defect may be revealed through a difference in grayscale values of the light reflected when light is irradiated to the pixel 130. Accordingly, when the pixel pattern 230 of the one unit pattern 210 has a different grayscale value from the corresponding pixel patterns 230 of the unit patterns 210 adjacent to the one unit pattern 210, It may be determined that a defect exists in the unit pattern 210.

In a conventional optical inspection method of a display panel, each unit pattern can be compared with the unit patterns surrounding it. For example, each of the unit patterns can be compared to the eight unit patterns surrounding it. However, unit patterns located in an area corresponding to an edge area of the display panel may be adjacent to an area corresponding to a peripheral area of the display panel where unit patterns are not arranged. When comparing the unit pattern located in the area corresponding to the edge area of the display panel with the eight unit patterns surrounding it, the unit pattern is compared to the area corresponding to the peripheral area of the display panel where the unit patterns are not arranged. By comparing with , it can be determined that the unit pattern has a defect even when there is no defect in the unit pattern. Accordingly, according to a conventional optical inspection method of a display panel, an area corresponding to an edge area of the display panel may be excluded from the inspection area. However, because of this, the inspection area of the display panel is reduced, and defects in the edge area of the display panel may not be found even by an optical inspection process.

FIG. 4 is a flow chart illustrating an example of comparing each of the unit patterns of FIG. 2 with adjacent unit patterns.

Referring to FIG. 4, virtual patterns created using unit patterns can be attached to the third area (S310). Thereafter, each of the unit patterns may be compared with the unit patterns and/or the virtual patterns surrounding them (S320).

FIG. 5 is a diagram showing an image obtained by attaching the virtual patterns of FIG. 4 to the third area.

Referring to FIG. 5 , virtual patterns 240 created using unit patterns 210 may be attached to the third area 220 of the image 200 (S310). For example, virtual patterns 240 can be created by copying unit patterns 210 located in the first area 212 or the second area 214 of the image 200, and these virtual patterns ( 240 may be attached to the third area 220 where the unit patterns 210 are not located. Each of the virtual patterns 240 may include pixel patterns 230. Accordingly, the area in the image 200 where patterns including the unit patterns 210 and the virtual patterns 240 are located may be expanded.

In example embodiments, the virtual patterns 240 may be created using unit patterns of the second area 214 . For example, virtual patterns 240 can be created by copying the unit patterns 210 located in the second area 214 of the image 200, and these virtual patterns 240 can be created in the third area (214). 220).

In one embodiment, four sub-images each including virtual patterns 240 can be created by copying each of the top, bottom, left, and right sides of the second area 214, and each of the four sub-images It can be attached to the adjacent third area 220. Here, the upper surface, lower surface, left surface, and right surface of the second area 214 are in the opposite direction to the second direction, the second direction, the opposite direction to the first direction, and the first direction, respectively. It can be located in . For example, the top surface of the second area 214 can be copied and pasted on the top surface of the adjacent third area 220, and the bottom surface of the second area 214 can be copied and placed on the adjacent third area 220. It can be attached to the lower surface of the second area 214 by copying the left surface of the second area 214 and attaching it to the left surface of the adjacent third area 220, and by copying the right surface of the second area 214 and attaching it to the adjacent third area ( 220) can be attached to the right side.

FIG. 6 is a diagram illustrating a comparison method comprising comparing each of the unit patterns of FIG. 4 with unit patterns and/or virtual patterns surrounding them.

Referring to FIG. 6, unit patterns 210 and/or virtual patterns 240 surround each of the unit patterns 210 in the first region 212 and the second region 214 of the image 200. ) can be compared with (S320).

In example embodiments, each of the unit patterns 210 of the first region 212 may be compared with the unit patterns 210 of the first region 212 and/or the second region 214 surrounding the unit patterns 210. Each of the unit patterns 210 of the second region 214 is formed by the unit patterns 210 of the first region 212 and the second region 214 surrounding it, and the third region 220. It can be compared with virtual patterns 240. For example, the gray level value of one pixel pattern 230a included in the one unit pattern 210a of the first area 212 is changed to the first area 212 and/or the first area surrounding the one unit pattern 210a. The grayscale values of the pixel patterns 230 corresponding to the one pixel pattern 230a included in the unit patterns 210 of the second area 214 may be compared. In addition, the grayscale value of one pixel pattern 230b included in the one unit pattern 210b of the second area 214 is changed to the first region 212 and the second region 214 surrounding the one unit pattern 210b. ) of the unit patterns 210 and the pixel patterns 230 corresponding to the one pixel pattern 230b included in the virtual patterns 240 of the third region 220. In this case, each of the virtual patterns 240 of the third area 220 is a virtual pattern copied from the unit pattern 210 of the first area 212 or the second area 214, and thus the unit pattern surrounding it Comparison with the fields 210 and the virtual patterns 240 may not be performed. Accordingly, like the unit patterns 210 of the first region 212, the unit patterns 210 of the second region 214 are compared with the unit patterns 210 and virtual patterns 240 surrounding the unit patterns 210. Thus, defects can be detected, and accordingly, the inspection area of the display panel 100 can be expanded.

In example embodiments, each of the unit patterns 210 may be compared with eight unit patterns 210 and/or virtual patterns 240 surrounding it. As shown in FIG. 6, each of the unit patterns 210 of the first area 212 may be adjacent to eight unit patterns 210, and the unit patterns 210 of the second area 214 may be adjacent to each other. Each may be adjacent to eight unit patterns 210 and virtual patterns 240. Accordingly, the pixel pattern 230 included in each of the unit patterns 210 of the first region 212 is adjacent to and includes the corresponding pixel patterns 230 included in the eight surrounding unit patterns 210. It can be compared with , and the pixel pattern 230 included in each of the unit patterns 210 of the second region 214 is included in the eight unit patterns 210 and virtual patterns 240 adjacent to and surrounding it. It can be compared with the corresponding pixel patterns 230. Accordingly, the unit pattern 210 to be inspected can be compared with more unit patterns 210 and virtual patterns 240, and the performance of optical inspection can be improved.

According to the optical inspection method of the display panel 100 according to exemplary embodiments of the present invention, not only the unit pattern 210 of the first area 212 but also the unit pattern 210 of the second area 214 has this pattern. Since it can be compared with the surrounding unit patterns 210 and/or virtual patterns 240, the inspection area of the display panel 100 can be expanded and the manufacturing time and manufacturing cost of the display panel 100 can be reduced. .

FIG. 7 is a flow chart illustrating another example of comparing each of the unit patterns of FIG. 2 with adjacent unit patterns. FIG. 8 is a diagram showing a comparison method using the steps of FIG. 7.

Referring to FIG. 7, each of the unit patterns in the first area can be compared with the unit patterns surrounding it (S330). Additionally, each of the unit patterns in the second area may be compared with unit patterns in the adjacent second area (S340).

Referring to FIG. 8 , each of the unit patterns 210 of the second region 214 can be compared with the unit patterns 210 of the second region 214 adjacent thereto. For example, the gray level value of the pixel pattern 230 included in each of the unit patterns 210 of the second area 214 is compared to the corresponding gray level value included in the unit patterns 210 of the adjacent second area 214. It can be compared with the grayscale values of the pixel patterns 230. In example embodiments, each of the unit patterns 210 of the second region 214 may be compared with two unit patterns 210 of the second region 214 adjacent thereto. For example, the unit pattern 210c located on the left or right side of the second area 214 may be compared with the unit patterns 210 located above and below the unit pattern 210c. Additionally, the unit pattern 210d located on the upper or lower surface of the second area 214 may be compared with the unit patterns 210 located on the left and right sides thereof. Accordingly, each of the unit patterns 210 of the second area 214 is not compared with the third area 220, but is compared only with the unit patterns 210 of the adjacent second area 214, thereby causing defects. can be detected.

Each of the unit patterns 210 of the first area 212 can be compared with the unit patterns 210 surrounding it. For example, the grayscale value of the pixel pattern 230 included in each of the unit patterns 210 of the first area 212 is changed to the unit of the first area 212 and/or the second area 214 surrounding the pixel pattern 230. The grayscale values of the corresponding pixel patterns 230 included in the patterns 210 may be compared. In example embodiments, one unit pattern 210e of the first region 212 may be compared with eight unit patterns 210 surrounding it. Accordingly, the unit pattern 210 of the first area 212 to be inspected can be compared with more unit patterns 210, and the performance of optical inspection can be improved.

Referring again to FIG. 2, it is possible to determine whether a defect exists in each of the unit patterns, and if a defect exists, location information about the defect can be obtained (S400). For example, as described above, the grayscale value of the pixel pattern 230 included in the unit pattern 210 to be inspected and the corresponding pixel patterns 230 included in the unit patterns 210 adjacent thereto By comparing the grayscale values of , it can be determined whether a defect exists in the unit pattern 210. Thereafter, when it is determined that a defect exists, location information on the unit pattern 210 where the defect exists and the pixel pattern 230 included in the unit pattern 210 can be obtained. Accordingly, by identifying defects in the display panel 100 during the manufacturing process or after manufacturing is completed using information on the presence or absence of defects and the location of the defect, defects can be quickly removed and the manufacturing cost of the display panel 100 can be reduced. You can.

The optical inspection method of a display panel according to exemplary embodiments of the present invention is applicable to computers, laptops, mobile phones, smartphones, smart pads, personal media players (PMPs), personal digital assistance (PDAs), MP3 players, etc. It can be applied to the optical inspection process of display devices included in electronic devices.

Above, optical inspection methods of a display panel according to exemplary embodiments of the present invention have been described with reference to the drawings, but the described embodiments are illustrative and do not depart from the technical spirit of the present invention as set forth in the claims below. It may be modified and changed within the scope by a person with ordinary knowledge in the relevant technical field.

100: display panel 110: display area
112: central area 114: edge area
120: Surrounding area 130: Pixels
200: Video 210: Unit patterns
212: first area 214: second area
220: Third area 230: Pixel patterns
240: Virtual patterns

Claims (15)

acquiring an image including a first area, a second area surrounding the first area, and a third area surrounding the second area by photographing the display panel;
extracting periodically arranged unit patterns from the first area and the second area of the image;
attaching virtual patterns created using the unit patterns to the third area;
Comparing each of the unit patterns with the unit patterns and/or the virtual patterns surrounding each of the unit patterns; and
An optical inspection method for a display panel comprising determining whether a defect exists in each of the unit patterns and, if a defect exists, obtaining location information of the defect. The display panel of claim 1, wherein the display panel includes a display area including a central area and an edge area, and a peripheral area surrounding the display area,
The first area corresponds to the central area, the second area corresponds to the edge area, and the third area corresponds to the peripheral area. The optical inspection method of a display panel according to claim 1, wherein the virtual patterns are created using the unit patterns in the second area. The method of claim 1, wherein each of the unit patterns of the first area is compared with the unit patterns of the first area and/or the second area surrounding the unit pattern,
Each of the unit patterns in the second area is compared with the unit patterns in the first area and the second area surrounding the unit pattern, and the virtual patterns in the third area. method of inspection. The optical inspection method of a display panel according to claim 1, wherein each of the unit patterns is compared with eight unit patterns and/or the virtual patterns surrounding the unit patterns. The optical inspection method of a display panel according to claim 1, wherein each of the unit patterns and the virtual patterns includes pixel patterns corresponding to pixels included in the display panel. The method of claim 6, wherein comparing each of the unit patterns with the unit patterns and/or the virtual patterns surrounding each of the unit patterns includes pixel patterns included in each of the unit patterns and the virtual patterns. An optical inspection method for a display panel, comprising comparing corresponding pixel patterns. The optical inspection method of a display panel according to claim 7, wherein comparing the corresponding pixel patterns includes comparing grayscale values of the corresponding pixel patterns. acquiring an image including a first area, a second area surrounding the first area, and a third area surrounding the second area by photographing the display panel;
extracting periodically arranged unit patterns from the first area and the second area of the image;
comparing each of the unit patterns in the first area with the unit patterns surrounding the unit patterns;
comparing each of the unit patterns in the second area with the unit patterns in the second area adjacent thereto; and
An optical inspection method for a display panel comprising determining whether a defect exists in each of the unit patterns and, if a defect exists, obtaining location information of the defect. The display panel of claim 9, wherein the display panel includes a display area including a central area and an edge area, and a peripheral area surrounding the display area,
The first area corresponds to the central area, the second area corresponds to the edge area, and the third area corresponds to the peripheral area. The optical inspection method of a display panel according to claim 9, wherein each of the unit patterns in the first area is compared with eight unit patterns surrounding it. The optical inspection method of a display panel according to claim 9, wherein each of the unit patterns in the second area is compared with two adjacent unit patterns. The optical inspection method of a display panel according to claim 9, wherein each of the unit patterns includes pixel patterns corresponding to pixels included in the display panel. The method of claim 13, further comprising: comparing each of the unit patterns in the first area with the unit patterns surrounding the unit patterns; and comparing each of the unit patterns in the second area with the unit patterns in the second area adjacent thereto. The step of comparing the patterns is an optical inspection method of a display panel, wherein the step of comparing the pixel patterns included in each of the unit patterns compares corresponding pixel patterns. The optical inspection method of a display panel according to claim 14, wherein comparing the corresponding pixel patterns includes comparing grayscale values of the corresponding pixel patterns.