Projection device with a folded optical path and wire-grid polarizer
US7789515B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 17, 2007 |
| Grant date | Sep 7, 2010 |
| Priority date | — |
| Expiry date | Jul 7, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/28
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A folded projection display system includes a wire-grid polarizer placed immediately behind the system's imaging screen. The display system includes an image projector that projects an image beam containing light of a predetermined linear polarization toward the imaging screen. The wire-grid polarizer reflects the light in the image beam away from the screen. The reflected image beam then encounters a ¼-wavelength achromatic retarder that converts the linear polarization to circular polarization. The image beam next hits a mirror that reflects the light back through the ¼-wavelength achromatic retarder, which converts the circular polarization back to linear polarization, with the polarization director rotated 90 degrees from the original polarization direction. The wire-grid polarizer then allows the light to pass through to the image screen.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.