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:
Jan. 10, 1995
Filed:
Jun. 01, 1993
Mitsuya Okada, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A signal information recorded on a recording layer formed on a phase-change type optical disk is reproduced as a phase change. Laser light emitted from a laser light source is collimated to a reference light by a lens. The reference light is divided by a beam splitter into a first reference light and a second reference light. The first reference light is directed through a condenser lens to the recording layer of the optical disk. A reflection light from the recording layer is directed through the beam splitter and a second condenser lens to an optical detector. The second reference light is passed through a phase difference plate, a reflection mirror, the phase difference plate, the beam splitter and then through the second condenser lens to the optical detector as a phase shifted reference light. At an input end of the optical detector, the reflection light and the phase-shifted reference light interfere with each other and the signal information having substantially no phase jitter is obtained at an output of the optical detector.