Reflection type overhead projector
US5206673A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 1991 |
| Grant date | Apr 27, 1993 |
| Priority date | — |
| Expiry date | Jul 19, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133528
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A mirror Fresnel lens (12) is disposed on a base (11), on which a liquid crystal display (18) is mounted. The liquid crystal display (18) is provided with a polarization plate (24) only in the mirror Fresnel lens (12) side. Light from a light source (15) passes through the liquid crystal display (18), is reflected by the mirror Fresnel lens (12), again passes through the liquid crystal display (18), is converged by a projection lens 16 and reflected by the mirror (17) and eventually arrives at a screen (20). A separated polarization plate (25) is provided in a manner to overlap with the projection lens 16. The separated polarization plate (25) is paired with the polarization plate (24).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.