To enhance the photoelectric conversion efficiency of CIS solar batteries and the like, and reduce the manufacturing cost thereof by originating a substrate material having a high mechanical strength and heat resistance, and a proper thermal expansion coefficient.

A tempered glass has a glass composition of, in mass%, 40 to 75% SiO2, 10 to 30% Al2O3, 0 to 10% B2O3, 3 to 20% Li2O+Na2O+K2O (the total amount of Li2O+Na2O+K2O ), 0 to 20% Na2O, 0 to 15% K2O, 1 to 20% MgO+CaO+SrO+BaO (the total of MgO+CaO+SrO+BaO), 1 to 15% CaO, and 0 to 15% ZrO2, and substantially does not contain As2O3, Sb2O3, PbO and F, and has a mass ratio of Al2O3/SiO2of 0.1 to 0.7, and a mass ratio of ZrO2/Al2O3of 0 to 0.3.

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