Patent ID: 6410466
Filing Date: 2002-06-25
Classification: C03C,G02B

Abstract:
Glass-ceramics for a light filter having a coefficient of thermal expansion within a range from 95Ã—10âˆ’7/C. to 140Ã—10âˆ’7/C. within a temperature range from âˆ’20 C. to +70 C., having light transmittance for plate thickness of 10 mm which is 60% or over within a wavelength range from 950 nm to 1600 nm, containing, as predominant crystal phases,(a) lithium disilicate, and (b) at least one selected from the group consisting of &agr;-quartz, &agr;-quartz solid solution, &agr;-cristobalite and &agr;-cristobalite solid solution, and having a composition which consists essentially in weight percent of: SiO270-77%Li2O8-12%K2O0.5-3%MgO + ZnO + SrO + BaO1-5%P2O51.5-3%ZrO22-7%Al2O33-9%Sb2O3 + As2O30-2%.