Projection lens system with long back focal length
US8498066B2 · kind B2 · utility
3Cited by
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8Claims
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Key dates
| Filing date | Dec 30, 2011 |
| Grant date | Jul 30, 2013 |
| Priority date | — |
| Expiry date | Dec 30, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/18
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection lens system, in the order from a magnified side to a reduced side, includes a first lens group with negative refraction power and a second lens group with positive refraction power. The projection lens system satisfies the formulas: −1.55<F1/F2<−1.12; wherein F1 is the effective focal length of the first lens group, and F2 is the effective focal length of the second lens group.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.