Patent ID: 8652979

Claim:
A tempered glass substrate, comprising a compression stress layer on a plane surface thereof, wherein the tempered glass substrate has a glass composition comprising, in terms of mole %, 50 to 85% of SiO 2 , 5 to 30% of Al 2 O 3 , 0 to 20% of Li 2 O, 7 to 20% of Na 2 O, 0 to 4% of K 2 O, 0.001 to 10% of TiO 2 , 0 to 0.1% of ZrO 2 , 0 to 1% of CaO, and 15 to 35% of Li 2 O+Na 2 O+K 2 O+Al 2 O 3 , has a (Li 2 O+Na 2 O+K 2 O)/Al 2 O 3 value of 0.7 to 3 in terms of mole fraction, a K 2 O/(Li 2 O+Na 2 O+K 2 O) value of 0 to 0.11 in terms of mole fraction, and is substantially free of As 2 O 3 and F.