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:
Dec. 21, 1993
Filed:
Sep. 19, 1991
Toshiya Nagahama, Nara, JP;
Shigehiro Yamada, Yamatokoriyama, JP;
Naruichi Yokogawa, Kitakatsuragi, JP;
Yasushi Seike, Higashihiroshima, JP;
Koji Yoshifusa, Higashihiroshima, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
An optical pickup using a holographic optical element includes a light source, a lens system for converting an optical beam outputted from the light source onto a recording carrier, a photodetector for detecting reflected light from the recording carrier and a diffraction grating for introducing the reflected light from the recording carrier to the photodetector in a light path connecting the recording carrier and the light receiving element. The photodetector includes a photodiode and a signal processing circuit which at least amplifies the output signal of the photodiode.