Folded optical system having improved image isolation
US6271969A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 11, 1998 |
| Grant date | Aug 7, 2001 |
| Priority date | — |
| Expiry date | Dec 11, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B2027/0116
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical collimating assembly for imaging light from a display. The optical assembly includes first and second linear polarization filters having polarization directions that are orthogonal to one another. A folded imaging assembly that includes a first beam splitter, a first 1/4 wave plate, and a second beam splitter is located between the polarization filters. A second 1/4 wave plate is also located between the polarization filters. The first 1/4 wave plate has a birefringence axis that is orthogonal to the birefringence axis of the second 1/4 wave plate. In the preferred embodiment of the present invention, the 1/4 wave plates are constructed from the same birefringent material. One of the reflectors is preferably constructed from a material having a reflectivity that depends on the direction of linear polarization of light striking the beam splitter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.