Optical relay lens system for projection displays
US5597222A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 17, 1995 |
| Grant date | Jan 28, 1997 |
| Priority date | — |
| Expiry date | Jan 17, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3105
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A projection display which includes reflective light valves such as liquid crystal spatial light modulators, and a 1.times. optical relay lens system. The 1.times. optical relay lens system eliminates the requirement for a projection lens having a large retrofocus distance. Projection displays based upon reflective liquid crystal light valves (spatial light modulators) require dichroic beam splitters necessary for color separation and a polarizing beam splitter necessary for light valve operation positioned between the light valves and the projection lens. The 1.times. optical relay lens produces a relayed intermediate image of the light valves, and incorporates therein the dichroic beam splitters and the polarizing beam splitter. The 1.times. optical relay lens produces an intermediate image which is projected by the projection lens at a given magnification with minimal working distance, which results in relatively less residual lateral color and an inexpensive projection lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.