Objective lens system for microscopes
AssigneeOlympus Optical Co., Ltd.
InventorTakayoshi Togino
Life of this patent
Estimating the term…
Abstract
An objective lens system for microscopes comprising a first positive lens component, a second positive cemented doublet, a third lens unit comprising at least one cemented lens, a fourth meniscus cemented doublet having a convex surface on the object side and a fifth negative cemented doublet. Said objective lens system has a working distance longer than twice of its focal length and an image surface which is flat over a wide range up to a field number of 27.
Claims6
An objective lens system for microscopes comprising a first positive lens component, a second positive cemented doublet, a third lens unit comprising at least one cemented lens, a fourth meniscus cemented doublet component having a convex surface on the object side and a fifth negative cemented doublet component, said lens system being so designed as to satisfy the following conditions (1) through (4):
- 1.65<n.sub.I-1 ( 1)
- -4.0f<r.sub.I-2 /(n.sub.I-1 -1)<-2.0f (2)
- d.sub.I-1 <1.5f (3)
- 1.8f<r.sub.IV -3 /(n.sub.IV-2 -1)<2.2f (4)
- wherein the reference symbols represents focal length of said objective lens system as a whole, the reference symbol n.sub.i-j designates refractive index of the j th lens element of the i th lens component, the reference symbol r.sub.i-j denotes radius of curvature on the j th surface of the i th lens component and the reference symbol d.sub.i-j represents airspace reserved between the j th and j+1 th surfaces of the i th lens component.
Dependencies are inferred from the claim text.