CHEMICALLY STRENGTHENED GLASS

摘要

A chemically strengthened glass having a compressive stress layer formed in a surface layer thereof according to an ion exchange method, in which the glass has a surface roughness (Ra) of 0.20 nm or higher, a hydrogen concentration Y in a region to a depth X from an outermost surface of the glass satisfies the following relational equation (I) at X=from 0.1 to 0.4 (μm), a surface strength F (N) measured by a ball-on-ring test under the following conditions is (F≧1500×t2) relative to a sheet thickness t (mm) of the glass, and a surface of the glass has no polishing flaw:;Y=aX+b  (I);in which meanings of respective symbols in the equation (I) are as follows: Y: hydrogen concentration (as H2O, mol/L); X: depth from the outermost surface of the glass (μm); a: −0.270 to −0.005; and b: 0.020 to 0.220.

主权项

1. A chemically strengthened glass having a compressive stress layer formed in a surface layer thereof according to an ion exchange method,
wherein the glass has a surface roughness (Ra) of 0.20 nm or higher, a hydrogen concentration Y in a region to a depth X from an outermost surface of the glass satisfies the following relational equation (I) at X=from 0.1 to 0.4 (μm), a surface strength F (N) measured by a ball-on-ring test under the following conditions is (F≧1500×t2) relative to a sheet thickness t (mm) of the glass, and a surface of the glass has no polishing flaw:
Y=aX+b  (I)in which meanings of respective symbols in the equation (1) are as follows:
Y: hydrogen concentration (as H2O, mol/L); X: depth from the outermost surface of the glass (μm); a: −0.270 to −0.005; and b: 0.020 to 0.220, the conditions of the ball-on-ring test: a sheet of the glass having the sheet thickness t (mm) is disposed on a stainless ring whose diameter is 30 mm and whose contact part has a roundness with a curvature radius of 2.5 mm; while a steel ball having a diameter of 10 mm is kept in contact with the sheet of the glass, a center of the ring is subjected to a load by the ball under a static loading condition; and a fracture load (unit: N) at which the glass is fractured is taken as a BOR surface strength and an average value of twenty measured values thereof is taken as the surface strength F, provided that in a case where a fracture origin of the glass is separated from a loading point of the ball by 2 mm or more, the obtained value is excluded from data for calculating the average value.