Highly efficient single panel and two panel projection engines
US7237899B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 2003 |
| Grant date | Jul 3, 2007 |
| Priority date | — |
| Expiry date | May 16, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/315
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Single imager projection systems suffer from low light throughput, compared to three imager systems, because only one color band is illuminated at any one time. As a result, there is a need to increase the operating efficiency of the single imager projection system. The invention is directed to the incorporation of a high extinction ratio pre-polarizer, such as a compensated, multi-layer polarizer, in a single or dual imager projection system. This permits illumination with low f-number illumination light, and thus increases the efficiency of the projection system. The pre-polarizer may be incorporated within a polarization recovery unit to further enhance system efficiency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.