Polarization conversion element, polarization illuminator, display using the same illuminator, and projection type display
US5986809A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 1998 |
| Grant date | Nov 16, 1999 |
| Priority date | — |
| Expiry date | Feb 20, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3167
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A polarizing conversion device in accordance with the invention includes a first optical element for condensing an incident beam and forming a plurality of intermediate beams spatially separated from one another, and a second optical element for spatially separating each intermediate beam into two polarized beams and aligning the polarization directions of the polarized beams, thereby obtaining the same type of polarized beams. In the second optical element, a shading plate is placed to prevent light from directly entering a section corresponding to a reflecting plane of a polarizing separation unit array. Since the ability of separating the intermediate beam into two polarized beams is thereby enhanced, it is possible to perform conversion into the same type of polarized beams polarized in the same direction, with high efficiency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.