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. 05, 1995
Filed:
Jul. 21, 1993
Takahiro Miyake, Soraku, JP;
Yoshio Yoshida, Nara, JP;
Yasuo Nakata, Nara, JP;
Yukio Kurata, Tenri, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A polarization detector includes a polarization diffraction element having a substrate with two facing surfaces which are placed in parallel with each other, a first diffraction grating formed on one surface of the substrate, and a second diffraction grating formed on the other surface of the substrate, with light being incident upon the first diffraction grating. Further, each grating pitch of the first diffraction grating and the second diffraction grating are nearly equal to a wavelength of the incident light. A limiting member is also included for limiting an incident region of the incident light with respect to the polarization diffraction element. The limiting member is formed on a light incident side of the first diffraction grating. Further, a converging lens is included for respectively converging light transmitted through the first diffraction grating and the second diffraction grating and light diffracted by the first diffraction grating and the second diffraction grating into different beam spots. Finally, a pair of photodetectors are included for detecting each optical intensity of the two beam spots converged by the converging lens.