Patent ID: 7163904

Claim:
A borosilicate glass with a composition in a percent by weight on an oxide basis, including: 60–75% SiO 2 , 10–15% B 2 O 3 , 5–15% Na 2 O, 5–10% K 2 O, 0.1–1% CaO, 0.5–3% BaO, >0–1.7% TiO 2 , 0–0.5% Sb 2 O 3 , and normal refining agents, and having an edge wavelength λ c between 280 nm and 325 nm and a pass range internal transmittance (τ ip ) of greater than 98% and an optical density in a stop range of 1×10 5 with a sample thickness of 2 mm.