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.

Date of Patent:
Feb. 12, 2019

Filed:

Nov. 08, 2017
Applicant:

Seiko Epson Corporation, Tokyo, JP;

Inventor:

Nobutaka Minefuji, Azumino, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B 13/06 (2006.01); G02B 9/64 (2006.01); G02B 13/00 (2006.01);
U.S. Cl.
CPC ...
G02B 13/06 (2013.01); G02B 9/64 (2013.01); G02B 13/006 (2013.01); G02B 13/0045 (2013.01);
Abstract

An imaging lens system (imaging lens) having a focal length f is formed of a first lens group formed of three negative lenses and a single positive lens or a cemented lens and a second lens group having a positive focal length with the first lens group and the second lens group sequentially arranged from the enlargement side and employs the stereographic projection method that satisfies a condition of y=a·f·tan(θ/2) (α: 1.8≤α≤2.2). The thus configured imaging lens system readily allows distortion to be reduced at each image height y and the degree of compression to be also reduced for sufficient resolution at the periphery.


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