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:
Sep. 05, 1995
Filed:
Apr. 09, 1993
Syuichi Kikuchi, Yokohama, JP;
Takao Yamaguchi, Yokohama, JP;
Noriyuki Iwata, Fujisawa, JP;
Masami Itoh, Higashi-Kurume, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A zoom finder of a real image type has an objective lens having positive refracting power and an eyepiece having positive refracting power. The objective lens is constructed by first, second, third and fourth lens groups sequentially arranged from an object side. The first lens group has positive refracting power. The second lens group has negative refracting power. The third lens group has positive refracting power. The fourth lens group has positive refracting power. The zoom finder is constructed such that a real image is focused and formed by the objective lens between the fourth lens group and the eyepiece and is observed through the eyepiece. A magnification of the zoom finder is increased by moving the second lens group from the object side to an eyepiece side. A change in diopter caused by this increase in magnification is corrected by moving the fourth lens group. In accordance with the above structure, an entire length of the zoom finder is short and is not changed in a zooming operation. Further, the structure of a mechanical mechanism for displacing lenses in the zooming operation is simplified and no diopter of the zoom finder is changed in the zooming operation.