Polarization separation device and projection-type display apparatus
US6278552A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 3, 2000 |
| Grant date | Aug 21, 2001 |
| Priority date | — |
| Expiry date | May 3, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3167
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A polarization separation device has a grating having a recurring blaze-shaped grating pattern formed on one surface of a transparent base plate and an optically anisotropic material layer arranged adjacent to the grating and having different refractive indices in the direction in which the grating pattern recurs and in the direction perpendicular to that direction. The polarization separation device separates light incident thereon into two linearly polarized light components that have polarization planes perpendicular to each other in accordance with the polarization directions thereof by refracting one and simply transmitting the other of those two linearly polarized light components. Here, the refractive index N0 of the grating and the refractive indices Ne and Np of the optically anisotropic material layer with respect to one and the other, respectively, of the linearly polarized light components are defined as follows: EQU .vertline.Ne-N0.vertline..gtoreq.0.2, and EQU .vertline.Np-N0.vertline..ltoreq.0.03.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.