The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 07, 1977
Filed:
Oct. 10, 1975
Ikuo Mori, Kawasaki, JA;
Yoshiyuki Shimizu, Kawasaki, JA;
Nippon Kogaku K.K., Tokyo, JA;
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.