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. 27, 1993
Filed:
May. 23, 1991
Shigeru Ohuchida, Zama, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
In an apparatus for recording and reproducing optical information, a light beam splitter is disposed on an optical path between a laser beam source and an optical information recording medium. The light beam splitter has a three-beam forming diffraction grating on one face of this light beam splitter on a light-emitting side thereof. The light beam splitter also has a light branching diffraction grating on another face thereof. A light beam emitted from the laser beam source is divided into three beams by the three-beam forming diffraction grating. The light branching diffraction grating is used to branch light reflected from the optical information recording medium. A polarizing/separating diffraction grating is formed in the light beam splitter on the same plane as the three-beam forming diffraction grating. The polarizing/separating diffraction grating is used to polarize and separate a light beam branched by the light branching diffraction grating.