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:
Mar. 27, 1990
Filed:
Nov. 18, 1987
Applicant:
Inventors:
Tosio Higasihara, Ibaraki, JP;
Ken Yoshizawa, Ibaraki, JP;
Masahiro Suzuki, Ibaraki, JP;
Akira Gotoh, Torite, JP;
Yoshitane Tuburaya, Torite, JP;
Assignee:
Hitachi Maxell, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01D / ; G01D / ;
U.S. Cl.
CPC ...
428 65 ; 369282 ; 369286 ; 3461351 ; 346137 ; 430945 ;
Abstract
An optical recording disc which includes a pair of recording disc substrates opposed to each other with a space therebetween, with a hub situated at the central portion of the disc substrates so that there is formed the closed space between the disc substrates, thereby providing a dual sided recordable optical recording disc. The hub may be formed by a pair of hub halves. There is disposed an annular inner spacer and annular outer spacer around the hub so as to separate the pair of recording disc substrates.