The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 06, 2001
Filed:
Sep. 25, 1998
Masaya Okamoto, Ichihara, JP;
Shigeki Kuze, Ichihara, JP;
Idemitsu Petrochemical Co., Ltd., Tokyo, JP;
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.