System and method for using off-axis illumination in a reflective projection system
US6688748B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 2001 |
| Grant date | Feb 10, 2004 |
| Priority date | — |
| Expiry date | Jan 12, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3105
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A novel projection system includes an illumination source for emitting an illumination beam, a reflective display device for modulating the illumination beam to form a reflected imaging beam, a projection lens group having an optical axis, and a field lens group. The field lens group is de-centered with respect to the optical axis of the projection lens group and is disposed to redirect the illumination beam to illuminate the display device at a non-zero angle of incidence, and to redirect the reflected imaging beam along an optical path parallel to the optical path of the projection lens group. In a particular embodiment the display device is disposed on the optical axis of the projection lens group. In a more particular embodiment, the redirected portion of the optical path of the reflected imaging beam is coincident with the optical axis of the projection lens group. In another particular embodiment, the display device is tilted with respect to the optical axis of the projection lens group to accommodate the tilt in focal plane of the projection lens group caused by the redirection of the imaging beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.