Title:
COVER GLASS AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
Japanese Patent JP2015093796
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a cover glass which hardly develops cracking, chipping, or the like after the end of molding operation even when press molding is performed at a viscosity of logη=3-7 at starting of the molding operation and at a viscosity of logη=11-15 at termination of the molding operation, using glass having a temperature of 1150°C or less at a viscosity of logη=4, and also to provide a manufacturing method for the same.SOLUTION: A method for manufacturing cover glass manufactures cover glass for chemical strengthening, which is before being subjected to chemical strengthening treatment by ion exchange, by press-molding glass melted at high temperature, the method being characterized in that the glass has a glass composition in which the ratio α1/α2 is 9 or less when it is assumed that the temperature at a viscosity of logη=4 is 1150°C or less, the elongation quantity difference with respect to the temperature difference ΔT (where, ΔT is a constant value of 1°C or less) in the temperature range from the glass-transition temperature to the yield point is T1 indicating the maximum value, the mean coefficient of linear expansion in the range from T1-5°C to T1+5°C is α1, and the mean coefficient of linear expansion in the range from 30°C to 400°C is α2.
Inventors:
OGAKI AKIO
Application Number:
JP2013233092A
Publication Date:
May 18, 2015
Filing Date:
November 11, 2013
Export Citation:
Assignee:
KONICA MINOLTA INC
International Classes:
C03C3/085; C03C3/087; C03C3/091; C03C3/093; C03C21/00
Attorney, Agent or Firm:
Shizuo Sano
Inoue On
Inoue On