US-12620077-B2 - Surface inspection method and surface inspection device for display panel

Abstract

A surface inspection method includes applying a signal to a display panel so that the display panel displays a test pattern; capturing a surface of the display panel on which the test pattern is displayed with a camera; and processing a captured image data to obtain a surface distortion shape.

Inventors

• Byungkyu Son

Assignees

• SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION

Dates

Publication Date

20260505

Application Date

20230717

Priority Date

20221025

Claims (18)

1. 1 . A surface inspection method for inspecting a display panel, the method comprising: applying a signal to the display panel including pixels so that pixels of the display panel self-displays a test pattern; capturing a surface of the display panel on which the test pattern is displayed with a camera; processing a captured image data and obtaining a surface distortion shape of the surface of the display panel, and determining whether the surface of the display panel is defective based on the surface distortion shape.
2. 2 . The surface inspection method of claim 1 , wherein the test pattern includes a fringe pattern.
3. 3 . The surface inspection method of claim 2 , wherein the displaying the test pattern includes changing and displaying at least one of a position, a type, and a color of the fringe pattern.
4. 4 . The surface inspection method of claim 1 , wherein the capturing the surface of the display panel includes capturing while moving the camera within a range in which an optical axis of a lens of the camera defines an angle of about 15° to about 90° with respect to a plane of the display panel.
5. 5 . The surface inspection method of claim 4 , wherein the obtaining the surface distortion shape includes obtaining a three-dimensional distortion shape by combining distortion shapes of test patterns for each angle captured while moving the camera.
6. 6 . The surface inspection method of claim 1 , wherein the camera includes an area sensor or a line sensor.
7. 7 . The surface inspection method of claim 1 , wherein the camera includes a time delay integration sensor.
8. 8 . The surface inspection method of claim 1 , wherein the surface of the display panel includes a surface of an encapsulation layer of the display panel or a surface of an organic layer included in the encapsulation layer.
9. 9 . The surface inspection method of claim 1 , wherein the test pattern is displayed by a combination of light emitted by the pixels.
10. 10 . The surface inspection method of claim 1 , further comprising analyzing an obtained surface distortion shape and determining a defect.
11. 11 . A surface inspection device for inspecting a display panel, the surface inspection device comprising: a stage on which the display panel including pixels is disposed; a signal applying device which applies a signal to the display panel so that the pixels of the display panel self-displays a test pattern; a camera which captures a surface of the display panel in a state where the display panel displays the test pattern; and a controller which processes a captured image data and obtaining a surface distortion shape of the surface of the display panel, and determines whether the surface of the display panel is defective based on the surface distortion shape.
12. 12 . The surface inspection device of claim 11 , wherein the test pattern includes a fringe pattern.
13. 13 . The surface inspection device of claim 12 , wherein the test pattern is displayed by changing at least one of a position, a type, and a color of the fringe pattern.
14. 14 . The surface inspection device of claim 11 , wherein the camera captures while the camera moves within a range in which an optical axis of a lens of the camera defines an angle of about 15° to about 90° with respect to a plane of the display panel.
15. 15 . The surface inspection device of claim 11 , wherein the camera includes an area sensor or a line sensor.
16. 16 . The surface inspection device of claim 11 , wherein the camera includes a time delay integration sensor.
17. 17 . The surface inspection device of claim 11 , wherein the surface of the display panel includes a surface of an encapsulation layer of the display panel or a surface of an organic layer included in the encapsulation layer.
18. 18 . The surface inspection device of claim 11 , wherein the test pattern is displayed by a combination of light emitted by the pixels.

Description

This application claims priority to Korean Patent Application No. 10-2022-0138422 filed on Oct. 25, 2022, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which in its entirety is herein incorporated by reference. BACKGROUND (a) Field This disclosure relates to a surface inspection method and a surface inspection device for a display panel. (b) Description of the Related Art A display device such as a light-emitting display device and a liquid crystal display device includes a display panel providing a screen for displaying an image. The display panel may be formed by stacking several layers such as a conductive layer, a semiconductor layer, and an insulating layer on a substrate. Various inspections may be performed during and after manufacture of the display panel. An inspection may be performed on whether a surface of the display panel is defective in appearance, curvature, deformation, height, or the like, for example. SUMMARY For surface inspection of a display panel, three-dimensional data of a surface of the display panel may be obtained from an image obtained by projecting a pattern on the surface of the display panel and capturing a pattern reflected by the surface of the display panel with a camera. In order to perform the surface inspection, a projector for projecting the pattern on the surface of the display panel may be desired. In addition, there is a limit to a resolution of the pattern obtained through reflection by the surface of the display panel. Embodiments are to provide a device and a method for inspecting a surface of a display panel precisely in a simple manner. A surface inspection method in an embodiment includes applying a signal to a display panel so that the display panel displays a test pattern, capturing a surface of the display panel on which the test pattern is displayed with a camera, and processing a captured image data and obtaining a surface distortion shape. In an embodiment, the test pattern may include a fringe pattern. In an embodiment, the displaying the test pattern may include changing and displaying at least one of a position, a type, and a color of the fringe pattern. In an embodiment, the capturing the surface of the display panel may include capturing while moving the camera within a range in which an optical axis of a lens of the camera defines an angle of about 15° to about 90° with respect to a plane of the display panel. In an embodiment, the obtaining the surface distortion shape may include obtaining a three-dimensional (“3D”) distortion shape by combining distortion shapes of test patterns for each angle captured while moving the camera. In an embodiment, the camera may include an area sensor or a line sensor. In an embodiment, the camera may include a time delay integration (“TDI”) sensor. In an embodiment, the surface of the display panel may include a surface of an encapsulation layer of the display panel or a surface of an organic layer included in the encapsulation layer. In an embodiment, the display panel may include pixels, and the test pattern may be displayed by a combination of light emitted by the pixels. In an embodiment, the surface inspection method may further include analyzing an obtained surface distortion shape and determining a defect. A surface inspection device in an embodiment includes a stage on which a display panel is disposed, a signal applying device that applies a signal to the display panel so that the display panel displays a test pattern, and a camera that captures a surface of the display panel in a state where the display panel displays the test pattern. In an embodiment, the test pattern may include a fringe pattern. In an embodiment, the test pattern may be displayed by changing at least one of a position, a type, and a color of the fringe pattern. In an embodiment, the camera may capture while the camera moves within a range in which an optical axis of a lens of the camera defines an angle of about 15° to about 90° with respect to a plane of the display panel. In an embodiment, the camera may include an area sensor or a line sensor. In an embodiment, the camera may include a TDI sensor. In an embodiment, the surface of the display panel may include a surface of an encapsulation layer of the display panel or a surface of an organic layer included in the encapsulation layer. In an embodiment, the display panel may include pixels, and the test pattern may be displayed by a combination of light emitted by the pixels. By the embodiments, since the display panel itself displays a test pattern to perform surface inspection of the display panel, there is no need to project a fringe pattern on the surface of the display panel using a projector. In addition, since the display panel may display a fringe pattern with a shorter period than that of the projected fringe pattern, fine surface curvature may be detected. Therefore, in the embodiments, the surface of the display panel may be inspected simpl