US Patent 7315125 Aluminum-free borosilicate glass and applications thereof

The fluorescent lamp is made with an aluminum-free borosilicate glass having a composition, in percent by weight, based on oxide content of: SiO2, 65-77; B2O3, 7-20; Li2O, 0-2; Na2O, 0-4; K2O, 3-12; MgO, 0-2; CaO, 0-2; with MgO+CaO, 0-3; BaO, 0-3; ZnO, 0-2; ZrO2, 0.8-12; TiO2, 0-10; CeO2, 0-1; and F−, 0-0.6. Preferred embodiments with more than 1% by weight TiO2 have especially good UV blocking properties and are especially suitable for lamp glass for backlights. Other embodiments have good sealing properties to tungsten, KOVAR®, and molybdenum and have coefficients of thermal expansion α of 4.7 to 5.3×10−6/K, good chemical resistance, and a working point VA of between 990° C. and 1290° C.