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. 26, 2019
Filed:
Sep. 13, 2017
Applicant:
Canon Kabushiki Kaisha, Tokyo, JP;
Inventors:
Yuichi Gyoda, Utsunomiya, JP;
Kohei Kimura, Utsunomiya, JP;
Assignee:
CANON KABUSHIKI KAISHA, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
G02B 15/14 (2006.01); G02B 13/18 (2006.01); G02B 9/22 (2006.01); G02B 9/34 (2006.01); G02B 9/62 (2006.01); G02B 9/64 (2006.01);
U.S. Cl.
CPC ...
G02B 13/18 (2013.01); G02B 9/22 (2013.01); G02B 9/34 (2013.01); G02B 9/62 (2013.01); G02B 9/64 (2013.01);
Abstract
An optical system includes an aperture stop, and a focus lens unit arranged on an image side of the aperture stop, the focus lens unit having a negative refractive power and moving during focusing. The focus lens unit moves toward the image side during focusing from infinity to close distance. The focus lens unit includes a positive lens PL and a negative lens NL. An Abbe number νdNL of the material of the negative lens NL, a refractive index NdNL of the material of the negative lens NL at d-line, and an Abbe number νdPL of the material of the positive lens PL are set appropriately.