Projection optical system and projector
US11181722B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 2017 |
| Grant date | Nov 23, 2021 |
| Priority date | — |
| Expiry date | Dec 29, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/00
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection optical system that projects, while enlarging, an image displayed on an image display surface includes in order from an enlargement side: a first negative refractive power lens group; a second negative refractive power lens group; at least one positive or negative refractive power lens group; a stop; and a first positive refractive power lens group. The projection optical system causes magnification variation by varying distances between lens groups. The at least one positive or negative refractive power lens groups disposed between the second negative refractive power lens group and the stop is movable during the magnification variation. The first positive refractive power lens group is an only lens group that is positioned closer to a reduction side than the stop and is also movable during the magnification variation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.