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:
Jan. 23, 1990
Filed:
Jul. 09, 1987
Applicant:
Inventors:
Atsuki Hirose, Ibaraki, JP;
Tamotu Iida, Tsuchiura, JP;
Assignee:
Hitachi Maxell, Ltd., Ibaraki, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369275 ; 369109 ; 369111 ;
Abstract
An optical information recording medium having a sharp front face of an optical information recording pit to thereby reduce jitter of a reproduced optical signal. The front and back end portions of a pit are made to have a sharp edge and a wider portion. In a cutting operation for an original medium used for mass production of medium, the light exposure amount to a photoresist on the original medium is controlled to increase it at the front and back edge portions of a pit.