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:
Nov. 17, 2020
Filed:
Oct. 12, 2018
Canon Kabushiki Kaisha, Tokyo, JP;
Masato Katayose, Utsunomiya, JP;
CANON KABUSHIKI KAISHA, Tokyo, JP;
Abstract
An optical system of this invention includes a first lens unit having a positive refractive power that is moved to an object side for focusing from infinity to a close distance. The first lens unit consists of, in order from the object side to an image side, a first lens sub-unit, an aperture stop, and a second lens sub-unit including a positive lens. A positive lens made of a material having an extraordinary dispersion characteristic ΔθgF which is largest among the positive lenses included in the second lens sub-unit is represented by positive lens Lp. An extraordinary dispersion characteristic of the material of the positive lens Lp, a focal length of the positive lens Lp, a focal length of the first lens unit, a focal length of the first lens sub-unit, and a focal length f1b of the second lens sub-unit are each appropriately set.