Projection optical unit and projection type video display device using the unit
US7467872B2 · kind B2 · utility
9Cited by
1References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 26, 2005 |
| Grant date | Dec 23, 2008 |
| Priority date | — |
| Expiry date | Apr 13, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/0025
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In the image display device, a projection lens including a plurality of lenses for enlarging an image from an image display element is constituted of a front group and a rear group. The rear group includes at least one free-shaped-surface lens including a surface having a rotationally asymmetrical shape. Furthermore, the device includes at least one free-shaped-surface mirror having a rotationally asymmetrical reflection surface. Accordingly, a set can be formed to be compact while correcting trapezoidal distortion and aberration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.