US 12,006,252 B2
Chemically strengthened glass with a film and method for measuring surface stress of chemically strengthened glass
Seiki Ohara, Tokyo (JP); Shunji Wachi, Tokyo (JP); and Hironobu Sato, Tokyo (JP)
Assigned to AGC Inc., Tokyo (JP)
Filed by AGC Inc., Tokyo (JP)
Filed on Sep. 8, 2021, as Appl. No. 17/469,139.
Claims priority of application No. 2020-151342 (JP), filed on Sep. 9, 2020.
Prior Publication US 2022/0073425 A1, Mar. 10, 2022
Int. Cl. C03C 21/00 (2006.01); C03C 17/28 (2006.01); C03C 17/30 (2006.01); C03C 17/32 (2006.01); G01L 1/24 (2006.01)
CPC C03C 21/002 (2013.01) [C03C 17/28 (2013.01); C03C 17/30 (2013.01); C03C 17/32 (2013.01); G01L 1/24 (2013.01); C03C 2217/732 (2013.01); C03C 2218/151 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A chemically strengthened glass with a film, comprising:
a chemically strengthened glass having a pair of main surfaces opposing each other; and
a film formed on at least one of the main surfaces of the chemically strengthened glass,
the chemically strengthened glass having a base composition comprising, in mole percentage on an oxide basis:
68.5-80% of SiO2;
8-20% of Al2O3;
0-10% of B2O3;
10.6-14% of Li2O;
2-12% of Na2O;
0-10% of K2O;
0-10% of a total content (MgO+CaO+SrO+BaO) of MgO, CaO, SrO, and BaO;
0-5% of a total content (ZrO2+TiO2) of ZrO2 and TiO2; and
7-20% of a total content (Li2O+Na2O+K2O) of Li2O, Na2O, and, K2O,
wherein the chemically strengthened glass has two or less interference fringes observed under stress measurement utilizing surface propagation light having a wavelength of 365 nm, and
the film has a refractive index lower than a refractive index of the chemically strengthened glass.