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. 01, 2022
Filed:
Jun. 19, 2019
Applicant:
Canon Kabushiki Kaisha, Tokyo, JP;
Inventor:
Hiroki Ebe, Utsunomiya, JP;
Assignee:
CANON KABUSHIKI KAISHA, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B 3/08 (2006.01); G02B 13/18 (2006.01); G02B 25/00 (2006.01); G02B 27/02 (2006.01); G02B 27/01 (2006.01);
U.S. Cl.
CPC ...
G02B 3/08 (2013.01); G02B 13/18 (2013.01); G02B 25/00 (2013.01); G02B 27/02 (2013.01); G02B 27/0172 (2013.01);
Abstract
An observation optical system according to the present invention includes a Fresnel lens and a lens LP with a positive refractive power provided on a light incident side or a light emitting side of the Fresnel lens. A length in a direction of an optical axis from a surface vertex of a central annular section of the Fresnel lens to an end portion of the central annular section is defined as h, and a length in the direction of the optical axis of a grating wall surface of a first annular section adjacent to the central annular section is defined as h. The lengths hand hare set to appropriate values, respectively.