Objective lens
US4531815A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 3, 1983 |
| Grant date | Jul 30, 1985 |
| Priority date | — |
| Expiry date | Jun 3, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/02
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An objective lens has a positive first lens disposed at a position most distant from an object surface, a meniscus-shaped second lens disposed on the object side of the first lens and having its convex surface facing the object side, and a positive third lens disposed on the object side of the second lens. The objective lens satisfies the following conditions: EQU 0.9<.vertline.r.sub.4 .vertline./f<25 EQU -0.45<f/f.sub.2 <0.02 EQU d.sub.4 /f<0.18 where f is the total focal length of the entire system, r.sub.4 is the radius of curvature of the surface of the second lens which is adjacent to the object side, f.sub.2 is the focal length of the second lens, and d.sub.4 is the spacing between the second lens and the third lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.