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:
Aug. 16, 1988
Filed:
Apr. 27, 1987
Applicant:
Inventors:
Assignee:
Daicel Chemical Industries, Ltd., Osaka, JP;
Primary Examiner:
Int. Cl.
CPC ...
B29F / ;
U.S. Cl.
CPC ...
26432816 ; 264-11 ; 264106 ; 26432817 ;
Abstract
A disk substrate for a high-density information recording medium made by injection molding from polycarbonate is disclosed having an average molecular weight from 14,000 to 22,000 and having a thickness from 1.0 to 2.0 mm and a circular recording area of between two concentric circles having a radii of 40 to 170 mm, respectively. The birefringence of the substrate within the recording area is less than 25 mm and is uniformly distributed.