Portable image projection system having reduced weight and profile
US6471356B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 11, 2000 |
| Grant date | Oct 29, 2002 |
| Priority date | — |
| Expiry date | Nov 5, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3114
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image projector employs a prism assembly that receives incident light, illuminates a reflective light modulator, and receives therefrom reflected imaging light for direction toward a small-diameter light entry pupil of a light-weight, compact projection lens. The prism assembly includes compensating and output prism components having opposed surfaces separated by an air gap. The prism assembly sets up a correct illumination angle on the DMD and then separates the incident illumination light from the reflected imaging light. Each on-state micromechanical DMD mirror reflects the illumination light nearly normal to a horizontal datum plane, forming reflected imaging light that reflects off the air gap and reenters the prism assembly through the output prism component. A focusing lens disposed between the prism assembly and the DMD refracts the reflected imaging light into a converging imaging light bundle compatible with the small diameter light entry pupil of the projection lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.