Projection lens
US8363327B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 2010 |
| Grant date | Jan 29, 2013 |
| Priority date | — |
| Expiry date | Feb 7, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/22
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection lens includes a first lens group, a second lens group, and a third lens group. The first lens group is composed of a first lens. The first lens has a concave surface and a convex surface, and the concave surface of the first lens faces a reducing side of the projection lens. The second lens group has positive refractive power, and includes a second lens having positive refractive power and a third lens having negative refractive power. The second lens is a biconvex lens, and the third lens has a concave lens facing the reducing side. The third lens group is composed of a fourth lens, and the fourth lens has a convex surface facing a magnifying side of the projection lens. The first lens group, the second lens group, and the third lens group include at least two aspheric lenses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.