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:
Nov. 21, 2006
Filed:
Jul. 04, 2001
Naoki Nakanishi, Kurita-gun, JP;
Shoichi Takasuka, Osaka, JP;
Shinichi Ijima, Takatsuki, JP;
Hideyuki Nakanishi, Otsu, JP;
Naoki Nakanishi, Kurita-gun, JP;
Shoichi Takasuka, Osaka, JP;
Shinichi Ijima, Takatsuki, JP;
Hideyuki Nakanishi, Otsu, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical semiconductor device comprising an emitted beam branching section () which branches an emitted light beam from a laser device (), a reflected light beam branching section () which branches a reflected light beam from an information recording medium () into light beams different from each other in focused state, servo signal sensing photodetectors () which receive the branched reflected light beam in a defocused state, a first diffraction grating provided in the emitted light beam branching section for diffracting the reflected light beam having passed through the reflected light beam flux branching section, and a signal sensing photodetector () which receives the reflected light beam diffracted by the first diffraction grating.