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. 19, 1986
Filed:
May. 20, 1985
Takeshi Maeda, Kokubunji, JP;
Motoo Uno, Kokubunji, JP;
Kouji Muraoka, Hachioji, JP;
Masahiro Takasago, Odawara, JP;
Yasumitsu Mizoguchi, Odawara, JP;
Tokuya Kaneko, Odawara, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In an optical memory apparatus wherein predetermined information is optically recorded on a recording medium along guide grooves previously formed and then played back; an optical memory apparatus wherein, using a tracking signal and a signal indicating the quantity of reflected light at the time at which a projected light beam passes through the guide grooves, the directions in which the light beam passes through the grooves and the number of the guide grooves to be passed are detected, a seek control is performed by adding and subtracting the numbers of the guide grooves to be passed, depending upon the directions of passage, and fine positioning is thereafter performed by the use of the tracking signal.