| 摘要 |
PURPOSE: A lightweight front glass for cathode ray tube (CRT) is provided of which thickness is reduced and which has high X-ray absorption coefficient and mechanical strength. CONSTITUTION: A lightweight front glass for cathode ray tube having a face part displaying an image is prepared from an oxide composition consisting of, based on the total weight of oxides, 56 - 58.5 % by weight of SiO2, 1 - 3 % by weight of Al2O3, 0 - 0.5 % by weight of Li2O, 4 - 7.5 % by weight of Na2O, 7 - 11 % by weight of K2O, 0 - 0.2 % by weight of MgO, 0 - 0.3 % by weight of CaO, 7.5 - 9 % by weight of SrO, 11 - 13 % by weight of BaO, 1 - 2.5 % by weight of ZnO, 2.5 - 3.5 % by weight of ZrO2, 0.3 - 0.5 % by weight of TiO2, 0.2 - 0.5 % by weight of CeO2 and 0.2 - 0.5 % by weight of Sb2O3. This front glass is characterized in that it has a X-ray absorption coefficient of 34 cm¬-1 or more at 0.6 angstrom, and a measure of weight reduction represented by equation 1 is 0.07 - 0.09, and the surface of its face part has a residual compressive stress of 5 - 25 Mpa. In the equation 1, K is a measure of weight reduction; T is a thickness of the central area of its face part, expressed by inch; and D is a maximum diagonal length of its face part, expressed by inch.
|
