Polarizer, polarization light source and image display unit using them
US7443585B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 2003 |
| Grant date | Oct 28, 2008 |
| Priority date | — |
| Expiry date | Feb 11, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/13362
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A polarization component, capable of efficiently reflecting an obliquely transmitted light beam toward a light source without degrading the transmission-polarization property of a perpendicular incident light beam, is provided. A C-plate having an oblique retardation of at least λ/8 with respect to a light beam inclined by at least 30° is disposed between at least two reflective circular polarizer layers whose selective reflection wavelength bands of polarized light overlapping each other. A combination of a reflective linear polarizer and a quarter wavelength plate may be used instead of the reflective circular polarizer. Alternatively, a combination of two reflective linear polarizer layers and two quarter wavelength plate layers (Nz≧2) disposed therebetween can provide a similar effect. Further, a combination of two reflective linear polarizer layers and a half wavelength plate (Nz≧1.5) disposed therebetween may be used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.