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:
Feb. 20, 1996
Filed:
Oct. 18, 1993
Tooru Sasaki, Yokohama, JP;
Kunikazu Ohnishi, Yokosuka, JP;
Yasuo Kitada, Odawara, JP;
Masayuki Inoue, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A 2-laser optical head in which the number of optical parts is small and an arrangement is also simple and a whole optical system can be miniaturized. As a construction to realize the 2-laser optical head, there is a construction in a 2-laser optical head comprising at least: semiconductor laser devices for rewriting and reproducing; a beam splitter for transmitting a laser beam emitted from the reproducing semiconductor laser device and for reflecting a laser beam emitted from the rewriting semiconductor laser device; an objective lens for converging the laser beams and irradiating onto a recording surface of a magneto-optic disk, thereby forming a spot for reproduction and a spot for rewriting; a detection optical system for detecting a reflected light from the recording surface of the spot; and a detection optical system for detecting a reflected light from the recording surface of the spot, wherein a dichroism beam splitter is arranged in a manner such that the angles between normal vectors of incident surfaces and incident optical axes and are equal to 45.degree., and the occurrence of a phase difference which causes a deterioration of a deflecting state is corrected by a beam splitter.