Objective lens system for microscopes
AssigneeOlympus Optical Co., Ltd.
InventorTsutomu Tojo
Life of this patent
Estimating the term…
Abstract
An objective lens system for microscopes which has a large numerical aperture and a long working distance and wherein the secondary spectrum is sufficiently minimized and curvature of field, coma, etc. are favorably corrected over a wide range of visual field. Said objective lens system comprises a first single-element or cemented doublet lens component and at least three lens components, i.e., two cemented meniscus lens components so arranged as to face their concave surfaces each other and a cemented three-element lens component.
Claims7
An objective lens system for microscopes comprising a first meniscus lens component having a concave surface on the object side and positive refractive power, a second positive lens component, a third cemented meniscus lens component having a concave surface on the image side, a fourth cemented meniscus lens component having a concave surface on the object side, a fifth positive lens component and a sixth cemented three-element lens component, and said lens system satisfying the following conditions:
- 1. 85>n.sub.1 >1.70 (1)
- 100<(.nu..sub.3 -.nu..sub.4)+(.nu..sub.6 -.nu..sub.5)<103 (2) ##EQU3##
- 0.1f<d.sub.1 /n.sub.1 <0.3f (4)
- wherein the reference symbol d.sub.1 represents thickness of the first lens component, the reference symbol n.sub.1 designates refractive index of the first lens component, the reference symbols .nu..sub.3, .nu..sub.4, .nu..sub.5 and .nu..sub.6 denote Abbe's numbers of both the elements of the third lens component and both the elements of the fourth lens component respectively, the reference symbols .theta..sub.3, .theta..sub.4, .theta..sub.5 and .theta..sub.6 represent values of .theta. given by .theta.=(n.sub.g -n.sub.F)/(n.sub.F -n.sub.C) for both the elements of the third lens component and both the elements of the fourth lens component respectively and the reference symbol f designates focal length of the lens system as a whole.
Dependencies are inferred from the claim text.