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:
Jun. 22, 2021
Filed:
Apr. 04, 2018
Applicant:
Ricoh Company, Ltd., Tokyo, JP;
Inventors:
Takashi Kubota, Tokyo, JP;
Hibiki Tatsuno, Kanagawa, JP;
Assignee:
RICOH COMPANY, LTD., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B 13/16 (2006.01); G02B 9/64 (2006.01);
U.S. Cl.
CPC ...
G02B 13/16 (2013.01); G02B 9/64 (2013.01);
Abstract
A projection optical system is for an image projection device. The projection optical system includes a whole lens system of seven to nine lenses and an aperture stop. The seven to nine lenses are all single lenses. One negative lens and one or two positive lenses are located on a magnifying side with respect to the aperture stop. Two negative lenses and three or four positive lenses are located on a reducing side with respect to the aperture stop. A lens adjacent to the magnifying side of the aperture stop and a lens adjacent to the reducing side of the aperture stop are both a negative lens.