# US 8,787,980 B2 · Glass substrate of cover glass for portable electronic device, image display unit for portable electronic device, portable electronic device and method of manufacturing glass substrate of cover glass for portable electronic device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,787,980 B2 - Document ID: US8787980B2 - Status: Granted - Kind: B2 - Application number: 13/331,587 - Filed: 2011-12-20 - Published: 2012-12-27 - Granted: 2014-07-22 - Earliest claimed: 2010-12-27 - Assignees: Hoya Corporation - Applicants: Kazuaki Hashimoto; Tomoyuki Goto; Mitsugu Imai; Tetsuo Takano - Inventors: Kazuaki Hashimoto; Tomoyuki Goto; Mitsugu Imai; Tetsuo Takano - Web page: https://patentgrep.com/patent/US8787980B2 ## CPC - C03C 15/00: Surface treatment of glass, not in the form of fibres or filaments, by etching (etching or surface-brightening compositions, in general C09K13/00) - C03C 19/00: Surface treatment of glass, not in the form of fibres or filaments, by mechanical means (sand-blasting, grinding, or polishing glass B24) - C03C 21/002: {to perform ion-exchange between alkali ions (C03C21/005 takes precedence)} - G06F 3/041: Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means - Y10T 428/24355: Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.] - Y10T 428/24488: Differential nonuniformity at margin - Y10T 428/2495: Thickness [relative or absolute] - C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present invention provides a glass substrate of a cover glass for a portable electronic device. The glass substrate includes a front face, a back face and an edge face. The edge face is at least partially formed by means of an etching treatment. A compressive stress layer, formed by means of an ion-exchanging method, is disposed on each of the front and back faces of the glass substrate. The compressive stress layer has the same thickness both in a planar-directional center part thereof and in a planar-directional end part thereof on each of the front and back faces of the glass substrate. ## Claims ### Claim 1 A glass substrate of a cover glass for a portable electronic device, the glass substrate comprising: a front face; a back face; an edge face formed by an etching treatment on each of front and back faces, the edge face including first and second regions, the first region having a flat surface formed at a center region of the edge face in a thickness direction of the glass substrate, and the second region having a curved surface with a surface roughness Ra of less than or equal to 10 nm and being disposed at the front and back faces in the thickness direction of the glass substrate; and a compressive stress layer formed by an ion-exchanging method and disposed on each of the front and back faces, the compressive stress layer having the same thickness both in a planar-directional center part thereof and in a planar-directional end part thereof on each of the front and back faces. ### Claim 2 (depends on 1) The glass substrate of a cover glass for a portable electronic device according to claim 1, wherein the flat surface is formed by a polishing treatment on the center region of the edge face. ### Claim 3 (depends on 1) The glass substrate of a cover glass for a portable electronic device according to claim 1, wherein the flat surface is formed by an etching treatment on the center region of the edge face. ### Claim 4 (depends on 1) The glass substrate of a cover glass for a portable electronic device according to claim 1, wherein the edge face is a mirror surface. ### Claim 5 (depends on 1) The glass substrate of a cover glass for a portable electronic device according to claim 1, wherein at least one selected from the front and back faces are provided with at least a decoration layer. ### Claim 6 (depends on 1) The glass substrate of a cover glass for a portable electronic device according to claim 1, wherein the glass substrate is used for at least one selected from a cover glass for display panel protection and a touch panel. ### Claim 7 (depends on 1) An image display unit for a portable electronic device, comprising: an image display panel including a rectangular image display area; and a cover glass for a portable electronic device formed by the glass substrate of a cover glass for a portable electronic device according to claim 1, the cover glass disposed on an image display surface side of the image display panel, the cover glass having a planar shape roughly matched with a planar-directional contour of the image display area. ### Claim 8 (depends on 1) A portable electronic device, comprising: an image display panel; a cover glass for a portable electronic device formed by the glass substrate of a cover glass for a portable electronic device according to claim 1, the cover glass disposed on an image display surface side of the image display panel. ### Claim 9 (depends on 8) The portable electronic device according to claim 8, wherein the portable electronic device is a mobile phone. ### Claim 10 (depends on 8) The method of manufacturing a glass substrate of a cover glass for a portable electronic device according to claim 8, the method further comprising: polishing at least a part of a cut surface formed as a result of the step of cutting the ion-exchanged plate glass into pieces. ### Claim 11 (depends on 1) The glass substrate of a cover glass for a portable electronic device according to claim 1, further comprising a three-surface corner part formed as a boundary among the front or back face, the edge face, and another edge face intersecting with the edge face, the three-surface corner part having a round shape. ### Claim 12 A glass substrate of a cover glass for a portable electronic device, the glass substrate comprising: a front face; a back face; a compressive stress layer formed by an ion-exchanging method and only disposed on each of front and back faces of the glass substrate; and an edge face of the glass substrate formed by an etching treatment on each of front and back faces, the edge face having a flat surface, and a convex curved surface having a surface roughness Ra of less than or equal to 10 nm. ### Claim 13 A glass substrate of a cover glass for a portable electronic device, the glass substrate comprising: a front face; a back face; a compressive stress layer formed by an ion-exchanging method and only disposed on each of front and back faces of the glass substrate; and an edge face of the glass substrate formed by an etching treatment on each of front and back faces, the edge face including a flat surface formed by a polishing treatment on a partial region of the edge face and a curved surface with a surface roughness Ra of less than or equal to 10 nm. ### Claim 14 A method of manufacturing a glass substrate of a cover glass for a portable electronic device, the method comprising: executing an ion-exchanging treatment by causing a plate glass containing at least a type of alkaline metal to make contact with a molten salt containing at least a type of alkaline metal; forming an etching-proof layer on each of front and back faces of the ion-exchanged plate glass; patterning the etching-proof layer in such a manner that a part of a surface of the ion-exchanged plate glass is exposed; and cutting the ion-exchanged plate glass into pieces by performing an etching treatment on the exposed part of the ion-exchanged plate glass faces to make contact with an etchant. ### Claim 15 (depends on 14) The method of manufacturing a glass substrate of a cover glass for a portable electronic device according to claim 14, the method further comprising: forming at least a decoration later on at least one of the front and back faces of the ion-exchanged plate glass after the step of executing the ion-exchanging treatment and before the step of forming the etching-proof layer. ### Claim 16 A method of manufacturing a glass substrate of a cover glass for a portable electronic device, the method comprising: forming an etching-proof layer on each of front and back faces of a plate glass containing at least a type of alkaline metal after executing an ion-exchanging treatment in which the plate glass makes contact with a molten salt containing at least a type of alkaline metal; patterning the etching-proof layer in such a manner that a part of a surface of the ion-exchanged plate glass is exposed; and cutting the ion-exchanged plate glass into pieces by performing an etching treatment on the exposed part of the ion-exchanged plate glass faces to make contact with an etchant. ### Claim 17 (depends on 16) The method of manufacturing a glass substrate of a cover glass for a portable electronic device according to claim 16, the method further comprising: forming at least a decoration later on at least one of the front and back faces of the ion-exchanged plate glass after the step of executing the ion-exchanging treatment and before the step of forming the etching-proof layer.