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:
Oct. 31, 2006
Filed:
Dec. 15, 2004
Applicant:
Yoshiji Kawamura, Tochigi, JP;
Inventor:
Yoshiji Kawamura, Tochigi, JP;
Assignee:
Fujinon Sano Corporation, Sano, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B 5/30 (2006.01); G02B 27/28 (2006.01); G03B 21/14 (2006.01);
U.S. Cl.
CPC ...
Abstract
A polarization conversion element with four phase plates laminated on a substrate plate, in the order of first, second, third and fourth phase plates from a light incident side. The first and fourth phase plates have substantially same retardation values, while the second and third phase plate have substantially same retardation values. Ratio of the retardation value of the first phase plate to the retardation value of the second phase plate is in the range of 1:1 to 1:3. Relative to optical axis of the first phase plate, the second to fourth phase plates are set at the angles of 45 degrees, 90 degrees and 45 degrees, respectively.