Patent ID: 6217995
Filing Date: 2001-04-17
Classification: G02B,Y10T

Abstract:
An optical transparent resin sheet having a visible light transmittance of not less than 80%, a glass transition temperature of not lower than 150.degree. C. and a thickness of from 0.2 to 1.5 mm, which exhibits a birefringence index of not higher than 15 nm, a surface roughness Ra of not more than 0.1 .mu.m and an impact strength of not less than 600 gf.multidot.cm as calculated in terms of breakdown energy determined by DuPont dropping ball process impact resistance test, wherein said transparent resin is a polycarbonate or polyester carbonate, said transparent resin has a viscosity-average molecular weight of from 10,000 to 25,000, and said transparent resin comprises a carbonate connecting unit having a glass transition temperature of not lower than 130.degree. C. and containing a cyclic aliphatic group incorporated therein in an amount of not less than 5 mol-% based on the total weight of carbonate connecting units.