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:
Apr. 01, 1997
Filed:
Oct. 28, 1991
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
In an optical system comprising a light source section consisting of a semiconductor laser and a collimator lens, an objective lens for focusing a light beam on an optical disk, a beam splitter for separating part of the light beam reflected from the optical disk, a condenser lens, and a photosensor for detecting the separated light beam to produce a focusing and a tracking error signal, a plane parallel plate is provided between the light source section and the beam splitter. By rotating the plane parallel plate with an adjusting mechanism, the light beam undergoes a parallel shift, so that the intensity distribution of light being incident on the objective lens is varied and a tracking offset due to a deviation of the optical axis of the output light from the light source section can be compensated for. The plane parallel plate may be disposed between the beam splitter and the condenser lens.