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

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.

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.

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.

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.