Projection display apparatus, and light guide tube/light valve for use in the same
US5321789A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 1991 |
| Grant date | Jun 14, 1994 |
| Priority date | — |
| Expiry date | Sep 17, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/1334
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A light valve is a planar member in which liquid crystals are hermetically sealed, and allows the transmission of light in an almost parallel direction and selectively scattering undesired light. On a rear surface of the light valve is disposed a light guide tube which contains a plurality of minute apertures. Alternatively, one of the substrates which constitute the light valve may be made of a fiber plate. The fiber plate has a structure in which short optical fibers are stacked. The light guide tube or the fiber plate converges a luminous flux emitted from the light valve to improve the contrast of an image. A projection display apparatus is constituted of a light source, a light valve, either a light guide tube or a fiber plate, a lens, and a projection lens. A luminous flux emitted from either the light guide tube or the fiber plate is incident on the pupil of the projection lens by way of the lens, and the projection lens casts this luminous flux onto a screen, thus forming a projected image. The selectively scattered undesired light cannot pass through the light guide tube or file plate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.