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. 10, 1994
Filed:
Nov. 05, 1991
Tatsuya Sugita, Hitachi, JP;
Yoshio Sato, Hitachi, JP;
Nobuyoshi Tsuboi, Ibaraki, JP;
Hiroyuki Minemura, Hitachi, JP;
Hisashi Andoh, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An overwritable optical disk apparatus in which a finite conjugate optical system is employed. The apparatus comprises an optical head for converging diffused light from a light source onto an optical disk for performing data write/read operation, a driving unit for rotating the disk and a beam splitter for guiding the light reflected from the optical disk to a photodetector for detecting light reflected from the optical disk. Influence of disk displacement occurring in accompanying the rotation of the disk and disk eccentricity are suppressed to a minimum by encasing rotatably the optical disk within a credit card size casing which is adapted to be loaded and held stationarily in the optical disk apparatus. Thin structure of the optical head and miniaturization of the optical disk apparatus are realized with light utilization efficiency for data write/read operation being increased.