Polarization conversion unit, polarization illumination apparatus provided with the unit, and projector provided with the apparatus
US5381278A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 1993 |
| Grant date | Jan 10, 1995 |
| Priority date | — |
| Expiry date | Nov 1, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3167
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A polarization conversion unit is disclosed. In the unit, a definitely polarized light emitted from a light source is divided into a pair of lights differing in polarized state and are caused to be incident on the optical components including the polarizing beam splitter. The plane of polarization of one of the paired polarized light is rotated to be coincident with the plane of polarization of the other light by the optical components, so that the paired lights with the same plane of polarization are caused to be separately emitted. The optical component has a plano-convex lens which has a positive power and which is arranged at an exit side where the paired lights are separately emitted. The lens has a focal point at a position further than the position of the surface to be illuminated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.