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:
Jul. 18, 1989
Filed:
Nov. 10, 1986
Applicant:
Inventors:
Yukio Kurata, Tenri, JP;
Hideaki Sato, Tenri, JP;
Yasuo Nakata, Tenri, JP;
Nobuo Ogata, Tenri, JP;
Teruaki Inoue, Nara, JP;
Assignee:
Sharp Kabushiki Kaisha, Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
358296 ; 369100 ;
Abstract
A pick-up device which includes a light source and a condenser lens for effecting recording and reproduction of information by projecting a light beam as collected by the condenser lens onto a recording medium. A diffraction grating is provided between the light source and the condenser lens for dividing light returning from the recording medium by a diffraction grating so as to be directed to a photo-detector, to thereby obtain an optical detection signal.