Projection lens with high resolution and reduced overall length
US8139293B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Apr 13, 2010 |
| Grant date | Mar 20, 2012 |
| Priority date | — |
| Expiry date | Jun 14, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/1425
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An zoom projection lens includes, in this order from the screen-side to the SLM-side thereof, a negative lens group and a positive lens group, and satisfies: −2<Φ1/Φ2<−0.5, −2<EFL1/EFL(W)<−1.5, 1.5<EFL2/EFL(W)<1.75, −1.2<EFL1/EFL(T)<−1, 0.8<EFL2/EFL(T)<1.2, 0.5<EFL(W)/BFL(W)<0.6, 0.68<EFL(T)/BFL(T)<0.75, 6.2<TTL(W)/EFL(W)<6.5, and 3.5<TTL(T)/EFL(T)<3.6; where Φ1 and Φ2 represent refractive powers of the negative lens group and the positive lens group respectively, EFL(W), EFL(T), EFL1 and EFL2 represent effective focal lengths of the projection lens in a wide-angle state and in a telephoto state, the negative lens group, and the positive lens group respectively, TTL(W) and TTL(T) represent overall lengths of the projection lens in the wide-angle state and in the telephoto state respectively, and BFL(W) and BFL(T) represent rear focal lengths of the projection lens in the wide-angle state and in the telephoto state respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.