Projection optical unit and projection image display apparatus
US7159988B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 2004 |
| Grant date | Jan 9, 2007 |
| Priority date | — |
| Expiry date | Feb 15, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/142
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection optical unit has two lens groups. A first projection optical unit disposed closest to an image display element, temporarily forms a first enlarged image (magnification: M1) at the image display element side, rather than at a second projection optical unit. The first enlarged image is subsequently projected in an enlarged form (magnification: M2, wherein M2>M1) onto a screen via the second projection optical unit. A field lens group having positive refractive power is disposed between the first projection optical unit and the second projection optical unit. Consequently, the relationship between F2, which is the F-value of the second projection optical unit, and F1, which is the F-value of the first projection optical unit, becomes F2=F1/M1, whereby it is possible to realize very-wide-angle imaging at a field angle exceeding 90 degrees.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.