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EP-4737415-A2 - COVER WINDOW, METHOD OF MANUFACTURING THE COVER WINDOW, AND ELECTRONIC DEVICE INCLUDING THE COVER WINDOW

EP4737415A2EP 4737415 A2EP4737415 A2EP 4737415A2EP-4737415-A2

Abstract

A cover window, a method of manufacturing the cover window, and an electronic device including the cover window are provided. The cover window includes a first surface, a second surface facing the first surface, and a plurality of side surfaces between the first surface and the second surface. A radius of curvature of each of the side surfaces is about 15 µm to about 25 µm. A first side surface among the side surfaces comprises a plurality of etch pores. A difference between a maximum height and a minimum height of the etch pores overlapping each other in a direction in which the first side surface extends is about 0.1 µm to about 0.5 µm.

Inventors

  • KIM, HYUNG SIK
  • KIM, JEONG HO
  • KIM, JONG KI
  • MISHCHIK, Konstantin
  • YOO, Kyung Han
  • JANG, SEUNG HOON
  • JUNG, WOO HYUN

Assignees

  • Samsung Display Co., Ltd.

Dates

Publication Date
20260506
Application Date
20251028

Claims (20)

  1. A cover window (CW) comprising: a first surface (FS); a second surface (BS) opposite to the first surface (FS); and a plurality of side surfaces (SS1-SS4) between the first surface (FS) and the second surface (BS), wherein a radius of curvature of each of the side surfaces (SS1-SS4) is about 15 µm to about 25 µm, a first side surface (SS1) selected from among the side surfaces (SS1-SS4) comprises a plurality of etch pores (POR), and a difference between a maximum height and a minimum height of the etch pores (POR) overlapping each other in a direction (DR2) in which the first side surface (SS1) extends is about 0.1 µm to about 0.5 µm.
  2. The cover window (CW) of claim 1, wherein a difference between a radius of curvature of a second side surface (SS2) and a radius of curvature of the first side surface (SS1) among the side surfaces (SS1-SS4) is about 2.5 µm or less.
  3. The cover window (CW) of claim 1 or 2, wherein a width (Wss1) of the first side surface (SS1) is about 10 µm to about 20 µm.
  4. The cover window (CW) of at least one of claims 1 to 3, wherein the cover window (CW) has a thickness (Tcw) of about 30 µm to about 60 µm.
  5. A method of manufacturing a cover window (CW), especially a cover window (CW) according to at least one of claims 1 to 4, the method comprising the following steps: irradiating a laser beam (BM) to an area of a mother substrate (MSUB) which corresponds to a plurality of cover windows (CW) utilizing a laser device (LD) to separate the cover windows (CW) from the mother substrate (MSUB) and form laser spots (LS) on edges of each of the cover windows (CW); loading the cover windows (CW) into a cassette (CST); and etching the cover windows (CW) of the cassette (CST) utilizing an etchant (ETL) to reduce a thickness of each of the cover windows (CW) and form side surfaces (SS1-SS4) of each of the cover windows (CW).
  6. The method of claim 5, wherein a radius of curvature of each of the side surfaces (SS1-SS4) of each of the cover windows (CW) is about 15 µm to about 25 µm.
  7. The method of claim 5 or 6, wherein the irradiating of the laser beam (BM) to the area of the mother substrate (MSUB) which corresponds to the cover windows (CW) utilizing the laser device (LD) to separate the cover windows (CW) from the mother substrate (MSUB) and form the laser spots (LS) on the edges of each of the cover windows (CW) comprises scanning the laser beam (BM) multiple times in an area corresponding to any one of the cover windows (CW).
  8. The method of claim 7, wherein one scan of the laser beam (BM) comprises a plurality of first laser spots (LS1) and a plurality of second laser spots (LS2), and the first laser spots (LS1) and the second laser spots (LS2) do not overlap each other in a thickness direction (DR3) of the cover window (CW).
  9. The method of claim 8, wherein a length of each of the first laser spots (LS1) and the second laser spots (LS2) in the thickness direction (DR3) of the cover window (CW) is about 2 µm to about 20 µm.
  10. The method of claim 8 or 9, wherein in the thickness direction (DR3) of the cover window (CW), a distance (Dz1) between centers of two neighboring first laser spots (LS1) among the first laser spots (LS1) is about 5 µm to about 15 µm.
  11. The method of at least one of claims 8 to 10, wherein a distance (Dx1) between neighboring first laser spots (LS1) among the first laser spots (LS1) in a direction orthogonal to the thickness direction (DR3) of the cover window (CW) and orthogonal to a scanning direction of the laser device (LD) is about 0 µm to about 2 µm, and a distance (Dy1) between neighboring first laser spots (LS1) among the first laser spots (LS1) in the scanning direction of the laser device (LD) is about 5 µm to about 15 µm, and wherein a distance (Dy2) between neighboring second laser spots (LS2) among the second laser spots (LS2) in the scanning direction of the laser device (LD) is about 5 µm to about 15 µm.
  12. The method of at least one of claims 8 to 11, wherein at least two second laser spots (LS2) among the second laser spots (LS2) overlap each other in the thickness direction (DR3) of the cover window (CW).
  13. The method of at least one of claims 8 to 12, wherein a minimum distance (Dmin) between the first laser spots (LS1) and the second laser spots (LS2) in a direction orthogonal to the thickness direction (DR3) of the cover window (CW) and orthogonal to a scanning direction of the laser device (LD) is about 3 µm or greater.
  14. The method of at least one of claims 7 to 13, wherein the scanning of the laser beam (BM) multiple times in the area corresponding to any one of the cover windows (CW) comprises: scanning the laser beam (BM) along a first side virtual line (VSS1) corresponding to a first side surface (SS1) of the cover window (CW) with the laser device (LD) rotated 0 degrees; scanning the laser beam (BM) along a first corner virtual line (VCS1) corresponding to a first corner side surface (CS1) between the first side surface (SS1) and a second side surface (SS2) of the cover window (CW) while rotating the laser device (LD) from 0 degrees to about 90 degrees; scanning the laser beam (BM) along a second side virtual line (VSS2) corresponding to the second side surface (SS2) of the cover window (CW) with the laser device (LD) rotated about 90 degrees; scanning the laser beam (BM) along a second corner virtual line (VCS2) corresponding to a second corner side surface (CS2) between the second side surface (SS2) and a third side surface (SS3) of the cover window (CW) while rotating the laser device (LD) from about 90 degrees to about 180 degrees; scanning the laser beam (BM) along a third side virtual line (VSS3) corresponding to the third side surface (SS3) of the cover window (CW) with the laser device (LD) rotated about 180 degrees; scanning the laser beam (BM) along a third corner virtual line (VCS3) corresponding to a third corner side surface (CS3) between the third side surface (SS3) and a fourth side surface (SS4) of the cover window (CW) while rotating the laser device (LD) from about 180 degrees to about 270 degrees; scanning the laser beam (BM) along a fourth side virtual line (VSS4) corresponding to the fourth side surface (SS4) of the cover window (CW) with the laser device (LD) rotated about 270 degrees; and scanning the laser beam (BM) along a fourth corner virtual line (VCS4) corresponding to a fourth corner side surface (CS4) between the fourth side surface (SS4) and the first side surface (SS1) of the cover window (CW) while rotating the laser device (LD) from about 270 degrees to about 360 degrees.
  15. The method of claim 14, wherein the laser device (LD) outputs an elliptically polarized laser beam along the first side virtual line (VSS1), the first corner virtual line (VCS1), and the second side virtual line (VSS2).
  16. The method of claim 14 or 15, wherein the laser device (LD) outputs an elliptically polarized laser beam along the second corner virtual line (VCS2), the third side virtual line (VSS3), the third corner virtual line (VCS3), the fourth side virtual line (VSS4), and the fourth corner virtual line (VCS4).
  17. The method of at least one of claims 5 to 16, wherein a plurality of etch pores (POR) are formed on each of the side surfaces (SS1-SS4) of each of the cover windows (CW) by the etchant (ETL).
  18. The method of claim 17, wherein a difference between a maximum height and a minimum height of the etch pores (POR) in a direction in which each of the side surfaces (SS1-SS4) of each of the cover windows (CW) extends is about 0.1 µm to about 0.5 µm.
  19. The method of at least one of claims 5 to 18, wherein the thickness of each of the cover windows (CW) is reduced by about 20 % to about 50% by the etchant (ETL).
  20. An electronic device (11, 10.1a-e, 10.2a-c, 10.3) comprising: a display panel (100) comprising a bendable folding area (FDA) and a non-folding area (NFA1, NFA2) around or beside the folding area (FDA); and a cover window (CW) according to at least one of claims 1 to 4 on a surface of the display panel (100).

Description

The present invention relates to a cover window, a method of manufacturing the cover window, and an electronic device including the cover window. As the information society develops and progresses, demands for display devices for presenting information in the form of images have been continuously increasing in various forms. These display devices may include (e.g., be) liquid crystal displays, field emission displays, and/or light emitting displays. The light emitting displays encompass both organic light-emitting displays, which include organic light-emitting diode elements, and inorganic light-emitting displays, which include inorganic light-emitting diode elements. To enhance the portability of display devices while providing a wide display screen, flexible display devices, such as bendable or foldable display devices, have been developed and released recently. In this regard, the cover window of should possess flexible characteristics to enable folding. Additionally, processes such as computer numerical control (CNC) grinding and/or wet-etching of the side surfaces of the cover window are performed to improve the mechanical strength of the cover window. However, defects such as chipping may occur on the side surfaces of the cover window during the CNC process, resulting in higher manufacturing costs. Aspects and features of embodiments of the present invention are directed toward a cover window which may be manufactured at a reduced cost without a reduction in mechanical strength. Aspects and features of embodiments of the present invention are directed toward a method of manufacturing a cover window at a reduced cost without a reduction in mechanical strength. Aspects and features of embodiments of the present invention are directed toward an electronic device including a cover window which may be manufactured at a reduced cost without a reduction in mechanical strength. The present invention is defined by the features of the independent claims. The dependent claims and the description disclose preferred embodiments. However, embodiments of the present invention are not limited to those set forth herein. The above and other embodiments of the present invention will become more apparent to one of ordinary skill in the art to which the present invention pertains by referencing the detailed description of the present invention provided herein or learning by practice of the presented embodiments of the invention. According to one or more embodiments of the present invention, a cover window includes a first surface, which may be for example a front surface, a second surface which may be for example a back surface opposite to (e.g., facing away from) the first surface, and a plurality of side surfaces between the first surface and the second surface. A radius of curvature of each of the side surfaces is about 15 micrometers (µm) to about 25 µm (the radius of curvature is also termed as R, such that "R" may be use instead of "µm", for example about 15 R to about 25 R). A first side surface among the side surfaces includes a plurality of etch pores. A difference between a maximum height and a minimum height of the etch pores overlapping each other in a direction in which the first side surface extends is about 0.1 µm to about 0.5 µm. A difference between a radius of curvature of a second side surface and a radius of curvature of the first side surface among the side surfaces may be about 2.5 µm or less. A width of the first side surface may be about 10 µm to about 20 µm. The cover window may have a thickness of about 30 µm to about 60 µm. According to one or more embodiments of the present invention, a cover window includes a first surface, a second surface opposite to (e.g., facing) the first surface, and a first side surface between (e.g., arranged between) the first surface and the second surface. The first side surface includes a first central side surface having a radius of curvature of about 7 µm to about 13 µm, a first upper side surface between (e.g., arranged between) the first surface and the first central side surface, and a first lower side surface between (e.g., arranged between) the second surface and the first central side surface. The first upper side surface and the first lower side surface may each be flat. The first central side surface may include a plurality of etch pores, and a difference between a maximum height and a minimum height of the etch pores in a direction in which the first side surface extends is about 0.1 µm to about 0.5 µm. A width of the first upper side surface may be greater than a width of the first central side surface. A width of the first lower side surface may be greater than the width of the first central side surface. According to one or more embodiments of the present invention, there is provided a method of manufacturing a cover window, the method includes irradiating a laser beam to an area of a mother substrate which corresponds to a plurality of cover windows