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. 21, 1985
Filed:
Oct. 22, 1981
Applicant:
Inventors:
Toshihiko Takagi, Kawasaki, JP;
Yoshikazu Kobayashi, Kawasaki, JP;
Yoshiji Suzuki, Hamamatsu, JP;
Tsutomu Hara, Hamamatsu, JP;
Assignee:
Nippon Columbia Kabushikikaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369275 ; 369111 ;
Abstract
An optical record disc is provided having a guide signal pit previously formed on a base plate for reading out a tracking information by a laser beam. A reflection film is coated on the base plate including the guide signal pit portion, and the record blank portion. A record layer of a removing type is formed over the reflection film. The record layer has a uniform thickness over the record layer and a uniform thickness, of substantially smaller dimension over the guide signal pit portion.