Projector with plastic mirror
US5506642A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 1994 |
| Grant date | Apr 9, 1996 |
| Priority date | — |
| Expiry date | Dec 20, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/7408
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A projector comprising liquid crystal display panels and a projection lens for projecting the modulated light to a screen. A back surface reflection mirror including a transparent plastic sheet and a reflecting film is arranged between the projection lens and the screen. The mirror is thin and light and may have optical anisotropy. In order to eliminate an uneven pattern appearing in the screen caused by optical isotropy of the mirror and the difference between the light distribution characteristics in the screen for P- and S-polarized light, the projection lens and the back surface reflection mirror are arranged in such a relationship that a wave normal vector of an arbitrary component of the light projected by the projection lens and made incident to the back surface reflection mirror is not parallel to the optical axis of the plastic sheet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.