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:
Jan. 01, 2019
Filed:
Nov. 30, 2017
Konica Minolta, Inc., Tokyo, JP;
Atsuo Masui, Osaka, JP;
Konica Minolta, Inc., Tokyo, JP;
Abstract
A projection optical system projects, while enlarging, an image displayed on an image display surface and performs zooming by moving a plurality of lens groups arranged along a same optical axis. The projection optical system includes, from an enlargement side: a first lens group having a negative refractive power; a second lens group having a negative refractive power and movable during zooming; a third lens group having a positive refractive power and movable during zooming; and a lens group disposed at a most reduction-side position. The first lens group includes, from the enlargement side: a front group having a negative refractive power; and a rear group having a positive refractive power and including, from the enlargement side, a negative lens element and a positive lens element. For zooming from a wide-angle end to a telephoto end, the third lens group moves toward the enlargement side monotonically.