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:
Jun. 09, 2026
Filed:
Nov. 30, 2022
Seiko Epson Corporation, Tokyo, JP;
Nobutaka Minefuji, Omachi, JP;
Hitoshi Hirano, Suwa, JP;
SEIKO EPSON CORPORATION, Tokyo, JP;
Abstract
A projection system includes first and second lens groups respectively having negative and positive power sequentially arranged from the enlargement side toward the reduction side. The first lens group includes a first-a lens group having negative power, a first-b lens group located at the reduction side of the first-a lens group and having negative power, and a first-c lens group located at the reduction side of the first-b lens group and having positive power. The first-b lens group and the first-c lens group each move in the direction of the optical axis during focusing. The projection system satisfies 0.2<|F/F1b|<0.6 (1), 0.0<F/F1c<0.14 (2), BF/F>5.0 (3), where F, F1b, and F1c represent the respective focal lengths of the overall projection system, first-b lens group, and first-c lens group, and BF represents the back focal length in air.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile