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:
Feb. 19, 2013
Filed:
Aug. 23, 2010
Applicants:
Takahiro Nakayama, Yokohama, JP;
Yoshifumi Sudoh, Maehida, JP;
Inventors:
Takahiro Nakayama, Yokohama, JP;
Yoshifumi Sudoh, Maehida, JP;
Assignee:
Ricoh Company, Ltd., Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
G02B 9/04 (2006.01); G02B 3/08 (2006.01); G02B 5/28 (2006.01);
U.S. Cl.
CPC ...
Abstract
An imaging optical system includes an aperture stop, a first lens group disposed on an object side of the aperture stop, a second lens group disposed on an image side of the aperture stop and a plate-like ND filter disposed close to a position of the aperture stop in an optical axis direction of the first and second lens groups, and the second lens group includes positive refracting power as a whole, the ND filter is configured to be retractable from the optical axis, and to attenuate a passing light amount.