Patent ID: 6358873
Filing Date: 2002-03-19
Classification: C03C,H01K

Abstract:
Glass compositions suitable as an envelope for a tungsten halogen lamp, consisting essentially in terms of weight percent on the oxide basis, of about 50-62% SiO2, 10-17% Al2O3, 0-6% B2O3, 3.6-10% CaO, 0-7.5% MgO, 0.1-0.3% SrO, 2.4-18% BaO, 0-1% ZnO, 1-8% Nd2O3, and exhibiting a strain point between about 665Â° C. to about 750Â° C., a coefficient of thermal expansion from 25Â° C. to the set point, 5Â° C. above the glass strain point, between about 49-59Ã—10âˆ’7/Â° C., a liquidus temperature below about 1320Â° C., a viscosity at the liquidus temperature greater than about 2,000 poises, and a transmission at 585 nm of about 5 to about 60% for a 1.2 mm thickness.