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. 26, 1997
Filed:
Feb. 04, 1994
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Optical pickup apparatus using split beams impinging on different photo-detector areas includes optical structure for projecting a light beam polarized in a predetermined direction toward a recording medium where information is recorded. Optical separating structure is provided for dividing a light beam reflected by the recording medium, with modulation of its polarization state in accordance with the recorded information, into first and second light beams which are polarized in directions perpendicular to each other. First and second light detectors respectively detect the first and second light beams. Preferably, a single lens is located between the separation structure and the first and second light detectors for converging the first and second light beams. Also preferably, the first and second light detectors are formed on the same substrate and are each divided into a plurality of light receiving areas. Further, an amplifier circuit is preferably formed on the same substrate as the first and second light detectors. Where the amplifier is a differential amplifier, it may produce an information signal by differentiating output signals of the first and second light detectors.