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:
Sep. 03, 1996
Filed:
Aug. 02, 1994
Masahiro Oono, Tokyo, JP;
Hisashi Konno, Tokyo, JP;
Toshiyuki Kase, Tokyo, JP;
Katsuki Hayashi, Tokyo, JP;
Hiroshi Nishikawa, Tokyo, JP;
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A detecting apparatus which detects an inclination of an objective lens relative to a reference surface is provided. The objective lens is part of an optical data recording and reproducing apparatus in which data is optically recorded on and reproduced from a recording medium which is placed parallel to the reference surface. The apparatus includes a transparent parallel plate which is opposite the objective lens, parallel to the reference surface, and made of a material that is substantially optically equivalent to a transparent material of the recording medium. The apparatus further includes a reflecting mechanism for reflecting coherent light which has passed through the objective lens and the transparent parallel plate back towards the transparent parallel plate and the objective lens, and a beam splitting mechanism for splitting the coherent light into a first beam and a second beam. The apparatus further includes a wavefront rotating mechanism for rotating the first beam and the second beam about an optical axis in a manner such that the first beam and the second beam are rotated through 180 degrees with respect to one another, and a mechanism for superposing the first beam and the second beam to produce an optical interference.