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.:

US 6945651 B1

PDF
Full Text
Expired
Date of Patent:
Sep. 20, 2005

Filed:

Nov. 18, 2004
Applicants:

Masahiko Yatsu, Tokyo, JP;

Koji Hirata, Tokyo, JP;

Futoshi Yamasaki, Tokyo, JP;

Inventors:

Masahiko Yatsu, Tokyo, JP;

Koji Hirata, Tokyo, JP;

Futoshi Yamasaki, Tokyo, JP;

Assignee:

Hitachi, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03B021/14 ;
U.S. Cl.
CPC ...
Abstract

By making the beam polarization state in a cross prism having a dichroic function for an incident beam on a reflection type liquid crystal panel the same as that for a reflected ON beam, a small-sized, low cost projection type projector apparatus is provided. A Faraday rotator having a Faraday rotation angle of 45 degrees is disposed on an optical path between a PBS and a cross prism. A half-wave plate having such a polarization axis as to rotate a polarization angle of linearly polarized light by 45 or 135 degrees is disposed on an optical immediately before or behind the Faraday rotator.


Find Patent Forward Citations

Yatsu, Masahiko. (2005). Optical unit and projection type projector apparatus using the same (U.S. Patent No. 6945651). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/6945651

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