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. 29, 1989
Filed:
Sep. 09, 1987
Norifumi Miyamoto, Hitachi, JP;
Yoshio Sato, Hitachi, JP;
Nobuyoshi Tsuboi, Ibaraki, JP;
Satoshi Shimada, Hitachi, JP;
Hiroshi Sasaki, Hitachi, JP;
Hiroaki Koyanagi, Hitachi, JP;
Hiroyuki Minemura, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An optical head is disclosed, in which a plate-shaped optical wave guide comprises an optical system including a collimator lens, a beam splitter and an objective lens; a laser light source for emitting a laser light in the form of a light beam which is to be impinged on an optical recording medium; and electro-acoustic transducers are disposed between the beam splitter and the objective lens, the transducers being adapted to be driven by the outer electrical signal for producing surface acoustic waves in the optical wave guide, thereby establishing a condensation and rarefaction distribution in refractive index in the optical wave guide which distribution influences the direction of transmission and the degree of focusing of the light beam passing therethrough so that regulation of the tracking and the focal length can be effected without any mechanical movements.