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:
Mar. 30, 1999
Filed:
Oct. 30, 1997
Naoki Fukutake, Kawasaki, JP;
Nikon Corporation, Tokyo, JP;
Abstract
An inexpensive achromatic object lens for a microscope has a magnification of about 20 and a relatively long working distance. Aberrations are satisfactorily corrected even at the periphery of the image. The object lens includes a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power in this order from the object side. The first lens group consists of a positive lens and a cemented lens which is composed of a negative lens and a positive lens. The second lens group consists of a positive lens for converting the divergent light flux that has exited the first lens group into convergent light flux. The third lens group consists of a negative meniscus lens with its concave surface facing the image side. The object lens satisfies the conditions 4.0.ltoreq.f1/d0.ltoreq.15.0, 55.ltoreq.v2p, and 35.ltoreq.v1p-v1n.