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:
May. 25, 1993
Filed:
Dec. 10, 1991
Applicant:
Inventors:
Assignee:
TDK Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B32B / ;
U.S. Cl.
CPC ...
428 64 ; 428 65 ; 428913 ; 346 / ; 3461351 ; 430945 ;
Abstract
An optical recording disk is constructed using an injection molded substrate of a cyclic polyolefin having a recurring structural unit of the formula: ##STR1## wherein R.sub.1 and R.sub.2 are independently selected from hydrocarbon groups. The disk has a diameter of at least 200 mm, and is rotated at 1,800 rpm or higher during recording/reproducing operation. Despite a larger diameter, the disk experiences minimized occurrence of double refraction during high speed rotation, ensuring high outputs with a high C/N and a low noise level.