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:
Mar. 31, 2009
Filed:
Aug. 08, 2006
Applicants:
Toshiyuki Kawasaki, Kanagawa, JP;
Shigeru Oohchida, Tokyo, JP;
Tsuyoshi Suzudo, Miyagi, JP;
Koji Mori, Miyagi, JP;
Inventors:
Toshiyuki Kawasaki, Kanagawa, JP;
Shigeru Oohchida, Tokyo, JP;
Tsuyoshi Suzudo, Miyagi, JP;
Koji Mori, Miyagi, JP;
Assignee:
Ricoh Company, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B 5/18 (2006.01);
U.S. Cl.
CPC ...
Abstract
A diffraction grating with periodically arranged protrusions and grooves at a relatively narrow pitch and improved diffraction efficiency is disclosed. The protrusions of the grating are made of a material whose index of refraction is greater than that of the grooves, and the ratio of the width D of the protrusion to the pitch Λ of the protrusion is set equal to or less than 0.4 (D/Λ≦0.4).