Projection lens apparatus and rear projection type image display apparatus using the same
US6768594B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 28, 2002 |
| Grant date | Jul 27, 2004 |
| Priority date | — |
| Expiry date | Jun 23, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/08
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In a projection lens, there are arranged in order from a screen side, a first lens group including a meniscus lens having a convex lens surface in a central portion toward a screen with refracting power, a second lens group including a lens having a convex lens surface in a central portion toward a video generating source, a third lens group including a lens having convex lens surfaces in both sides with positive refracting power, a fourth lens group including a lens having a convex lens surface in a central portion toward the video generating source with positive refracting power, and a fifth lens group including a lens having a concave lens surface toward the screen with negative refracting power. An entrance pupil is arranged between incident and emitting surfaces of a power lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.