Parfocal low-magnification microscope objective lens systems
US4027951A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 10, 1975 |
| Grant date | Jun 7, 1977 |
| Priority date | — |
| Expiry date | Oct 10, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/02
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A parfocal low-magnification microscope objective lens system comprises, in succession from the object side, a positive first lens member, a negative second lens member and a positive third lens member. The first lens member has its concave surface facing the object; the second lens member includes at least one negative meniscus lens component with its concave surface facing the object; and the third lens member includes a positive lens component with that surface thereof sharper in radius of curvature facing the image plane side. The lens system satisfies the following four conditions: d.sub.A <f.sub.A <d.sub.A + .vertline.f.sub.B .vertline.; d.sub.A <d.sub.B ; .vertline.f.sub.B .vertline.<.vertline.f.sub.A .vertline.; and .vertline.d.sub.B .vertline.>.vertline.f.sub.B .vertline.; where f.sub.A and f.sub.B are the focal lengths of the first and the second lens member, respectively, d.sub.A is the distance from the rear principal plane of the first lens member to the front principal plane of the second lens member, and d.sub.B is the distance from the rear principal plane of the second lens member to the front principal plane of the third lens member.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.