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:
Aug. 08, 2023
Filed:
Jun. 25, 2019
Applicant:
Nittoh Inc., Nagano, JP;
Inventor:
Takahiko Matsuo, Nagano, JP;
Assignee:
Nittoh Inc., Nagano, JP;
Primary Examiner:
Int. Cl.
CPC ...
G03B 21/14 (2006.01); G02B 13/16 (2006.01); G02B 13/18 (2006.01);
U.S. Cl.
CPC ...
G03B 21/142 (2013.01); G02B 13/18 (2013.01);
Abstract
In a projection optical system for projecting an optical image from a first image plane on a reduction side onto a second image plane on a magnification side, the system includes an achromatic lens including a positive lens and a negative lens separately arranged in this order from the reduction side toward the magnification side, and the negative lens having a refractive index of 1.7 or higher and an Abbe's number of 55 or less satisfies the following expression:3.5≤|  (1),where the radius of curvature of a light incident surface is R and the focal length of an entire projection optical system is f.