Patent ID: 8367208
Filing Date: 2013-02-05
Classification: C03C,Y10T

Abstract:
1. A high strength, chemically toughened protective glass article, said protective glass article having a thickness less than or equal to 2.0 millimeters, a surface chemically toughed to a depth of at least 40 μm, and a high damage tolerance threshold of at least 1500 g as measured by the lack of the presence of radial cracks when the load is applied to the glass using a Vickers indenter and wherein the composition of the glass of said article comprising, before any ion exchange to chemically strengthen, 64 mol %≦SiO 2 ≦68 mol %; 12 mol %≦Na 2 O≦16 mol %; 8 mol %≦Al 2 O 3 ≦12 mol %; 0 mol %≦B 2 O 3 ≦3 mol %; 2 mol %≦K 2 O≦5 mol %; 4 mol %≦MgO≦6 mol %; and 0 mol %≦CaO≦5 mol %; 0-0.5% (As 2 O 3 , SnO 2 ); wherein: 66 mol %≦SiO 2 +B 2 O 3 +CaO≦69 mol %; Na 2 O+K 2 O+B 2 O 3 +MgO+CaO+SrO>10 mol %; 5 mol %≦MgO+CaO+SrO≦8 mol %; (Na 2 O+B 2 O 3 )—Al 2 O 3 ≦2 mol %; 2 mol %≦Na 2 O—Al 2 O 3 ≦6 mol %; and 4 mol %≦(Na 2 O+K 2 O)—Al 2 O 3 ≦10 mol %.