Projection display
US6036318A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 27, 1998 |
| Grant date | Mar 14, 2000 |
| Priority date | — |
| Expiry date | Jan 27, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/7441
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A projection type display apparatus 1 is roughly composed of a polarized light beam illumination device 100, a polarization beam splitter 200, a reflection type liquid crystal device 300, and a projection optical system 500. The polarized light beam illumination device 100 includes a light source unit 110, a first optical element 120 and a second optical element 130, and the light beams emerging from the light source unit 110 are divided into a plurality of intermediate light beams by the first optical element 120 and thereafter converted into polarized light beams having approximately one kind of a polarization direction by the second optical element 130. The polarized light beams are reflected at the polarization beam splitter 200 and modulated by the reflection type liquid crystal device 300 and thereafter projected to a projection surface 600 through the projection optical system 500. According to the projection type display apparatus arranged as described above, the length of a light path is shortened to thereby prevent light loss as well as uneven brightness to a region to be illuminated, by which a projected image having uniform brightness and good quality can be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.