Speckle minimization in projection displays by reducing spatial coherence of the image light
US4035068A · kind A · utility
168Cited by
5References
3Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jun 25, 1975 |
| Grant date | Jul 12, 1977 |
| Priority date | — |
| Expiry date | Jun 25, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3108
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical system for minimizing the speckle observed in a projected image, the image being produced by a projection display device. Coherent or non-coherent light illuminates the projection display device image and an image thereof is formed at an intermediate image plane. A narrow angle diffuser is positioned at the intermediate image plane and produces an enlarged illuminating aperture at the Fourier transform plane. The relatively large angle subtended by the illuminating aperture at a second image plane reduces the spatial coherence of the image formed thereat.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.