Projection lens with long working distance
US4426136A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 5, 1981 |
| Grant date | Jan 17, 1984 |
| Priority date | — |
| Expiry date | May 5, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B9/62
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection lens with a long working distance for projecting a magnified image of an object comprises, in the order from the image side, a diverging first lens group containing a positive lens element and a negative lens element, a diverging second lens group having a negative meniscus lens element with a convex surface thereof facing toward the image side, a converging third lens group containing a positive meniscus lens element whose concave surface faces toward the image side, a converging fourth lens group having a positive lens composed of mutually cemented negative lens element and positive lens element, and a converging fifth lens group. The projection lens of an elevated magnification has a working distance from twice to five times longer than the focal length and is bright with a limited number of lens components.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.