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. 28, 1990
Filed:
Dec. 29, 1987
Applicant:
Inventors:
Masaru Ito, Sagamihara, JP;
Hitoshi Watanabe, Yuuki, JP;
Toshiaki Taii, Yuuki, JP;
Yoshito Tsunoda, Suginami, JP;
Assignees:
Hitachi, Ltd., Tokyo, JP;
Hitachi Maxell, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4439 ; 369 31 ;
Abstract
A mastering machine for an optical disk provided with a closed loop for controlling the incident angle of at least one of the guide groove forming beam and header forming beam which enter a condenser lens, and thereby controlling to a predetermined level the distance between a guide groove forming light spot and a header forming light spot on a photosensitive layer.