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. 25, 1997
Filed:
Mar. 14, 1995
Masanobu Kaneko, Kanagawa-ken, JP;
Masaaki Yanagisawa, Kanagawa-ken, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A compact internal focus objective lens system utilized in an astronomical telescope, tenestrical telescope, photo lens or the like has a superior ability to compose images when focusing on close or near objects. The lens system includes, in order from the object side, a first lens group G1 with a positive refractory power and a second lens group G2 with a negative refractory power. The first lens group G1 includes a composite lens L1 with a negative lens L11 and a positive lens L12 and a single lens L2 with a positive refractory power. The second lens group G2 has a composite lens L3 that has an overall negative refractory power. The second lens group G2 is moved along the optical axis for focusing. The objective lens satisfies the following conditions, thus permitting the compact internal focus objective lens system to clearly compose images, when focusing on close or near objects: