Projection lens system
US6912095B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 24, 2003 |
| Grant date | Jun 28, 2005 |
| Priority date | — |
| Expiry date | Dec 3, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/22
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A compact and light-weighted projection lens system that is capable of projecting an image at an angle as wide as 75 degrees with sufficient field angle and brightness as represented by F number of approximately 2.4, that is capable of effectively correcting chroic aberration of magnification and aberration of distortion and exhibiting optical stability against environmental variations, and that is suitable for obtaining an extraordinarily fine image by the magnification and projection. In the projection lens system that comprises first to third groups of lenses in the order from the closest a magnified image where the first lens group of negative refractive power includes one or more aspherical lenses each having an aspherical plane on one or both of the surfaces, the second lens group of positive refractive power includes one or more positive lenses, and third lens group of positive refractive power includes one or more cemented triplet lenses comprised of three lenses of positive, negative, and positive attributes joined in this order, a projection lens system is characterized by terms and conditions defined as in the following formulae:0.9<|f1|/f<1.4 (1)2.1<f2/f<3.4 (2)1.9<f3…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.