Patent ID: 7667791

Claim:
An ultraviolet absorbing glass for fluorescent lamps used for a back light source of a display device, comprising a borosilicate glass substantially not comprising TiO 2 but comprising, in mass %, 0.001 to 0.05% of Fe 2 O 3 , 0.1 to 5% of CeO 2 , 0.01 to 5% of SnO+SnO 2 and 0.01 to 5% of ZrO 2 +ZnO+Nb 2 O 5 and having an average linear expansion coefficient in a range of 36 to 57×10 −7 /° C. at 0 to 300° C. defined in JIS R 3102, and to have a transmittance of 10% or less at a wavelength of 315 nm when a thickness is 0.3 mm and a degree of deterioration of 5% or less according to the following ultraviolet radiation test, wherein the degree of deterioration according to the ultraviolet radiation test is determined by positioning a glass, of which both sides having been optically polished so at to have a mirror surface and a thickness of 1 mm, at a distance of 20 cm with the polished surface faced to a 400 W high-pressure mercury lamp having a wavelength of 253.7 nm, exposing it to ultraviolet radiation for 300 hours, measuring a transmittance (T 1 ) at a wavelength of 400 nm, and determining a degree of deterioration from an initial transmittance (T 0 ) at a wavelength of 400 nm before the ultraviolet radiation by the following equation: the degree of deterioration (%)=[( T 0 −T 1 )/ T 0 ]×100.