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:
Apr. 30, 1996
Filed:
Jun. 06, 1994
Masami Itoh, Higashi Kurume, JP;
Shuichi Kikuchi, Yokohama, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A lens system includes a master lens system and a conversion lens system. The master lens system has a first lens, a second lens, a third lens, and a fourth lens, which are sequentially arranged from an object side of the lens system to an image side thereof, and has a first diaphragm which is arranged between the third lens and the fourth lens. The first lens is a positive meniscus lens having a convex surface toward the object side. The second lens is a negative lens. The third lens is a positive lens. The fourth lens is a negative meniscus lens having a concave surface toward the object side. The conversion lens system is arranged in such a manner that the conversion lens system can be freely inserted and removed between the third lens and the fourth lens of the master lens system. When the conversion lens system is inserted and removed between the third lens and the fourth lens, relative positions of the respective first, second, third and fourth lenses are fixed, and a focal length of the lens system becomes shorter than a focal length of the master lens system.