Digital video disk substrate

Abstract

A digital video disk substrate of a polycarbonate having a viscosity average molecular weight (Mv) of 10,000 to 17,000 and a weight average molecular weight (Mw)/number average molecular weight (Mn) of not smaller than 2.3, and a digital video disk substrate of a polycarbonate having a viscosity average molecular weight (Mv) of 1,000 to 17,000 obtained by the transesterification of a divalent phenol such as 2,2-bis(4-hydroxyphenyl) propane with a carbonic acid diester such as diphenyl carbonate. The digital video disk substrate is little cracked at the time of molding, and exhibits small birefringence and excellent transcriptional property.

Dependencies are inferred from the claim text.