Objectives
US5191473A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 1991 |
| Grant date | Mar 2, 1993 |
| Priority date | — |
| Expiry date | Oct 24, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/02
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An objective of some 10 magnifications usable with microscopes, etc. which has an increased numerical aperture and working distance, including a first lens component that is a cemented lens consisting of negative and positive lens elements, a second lens component a third lens component, a fourth lens component consisting of a cemented lens and a fifth lens component having a positive refractive power, characterized by satisfying the following conditions: EQU .nu..sub.I2 -.nu..sub.I1 >20 (1) EQU n.sub.I1 -n.sub.I2 >0.2 (2) wherein: PA0 n.sub.I1 is the refractive index of d-line of the negative lens element of the first component, PA0 .nu..sub.I1 is the Abbe's number of said negative lens element of the first lens component, PA0 n.sub.I2 is the refractive index for d-line of the positive lens element of the first lens component, and PA0 .nu..sub.I2 is the Abbe's number of said positive lens element of the first lens component.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.