Laser illuminated projection displays
US7244028B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 14, 2004 |
| Grant date | Jul 17, 2007 |
| Priority date | — |
| Expiry date | Jul 5, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3161
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A projection video display includes at least one laser for delivering a light beam. The display includes a beam homogenizer and a condenser lens. A scanning arrangement is provided for scanning the light in beam in a particular pattern over the condenser lens in a manner that effectively increases the beam divergence. The scanned beam is homogenized by a beam homogenizer and a spatial light modulator is arranged to receive the homogenized scanned light beam and spatially modulate the beam in accordance with a component of an image to be displayed. Projection optics are projecting the homogenized scanned light beam onto a screen. The scanning provides that the homogenized scanned light beam at the screen has a coherence radius less than the original coherence radius of the beam. The reduced coherence radius contributes to minimizing speckle contrast in the image displayed on the screen. The screen includes one or more features providing a further contribution to minimizing speckle contrast in the displayed image. In one example, the screen includes a transparent cell containing a liquid having light scattering particles in suspension.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.