Patent ID: 7687420

Claim:
A tempered glass comprising, in terms of mass percent, SiO 2 : 60 to 80%; Al 2 O 3 : 3 to 18%; B 2 O 3 : 0 to 7%; Li 2 O: 0.01 to 10%; Na 2 O: 4 to 16%; K 2 O: 0 to 15%; and R′O (wherein R′O indicates a total content of alkaline earth metal oxides): 0 to 5%, wherein a value of (Li 2 O)/(Na 2 O+K 2 O) in terms of molar ratio is within a range of 0.05 to 0.5, wherein a surface of the tempered glass is treated to form a compressive stress layer, and wherein a liquidus viscosity is 10 5.0 dPas or more.