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. 10, 1984
Filed:
May. 22, 1981
Yutaka Iizuka, Tokyo, JP;
Nippon Kogaku K.K., Tokyo, JP;
Abstract
An Albada finder device includes a field frame provided on an eyepiece lens so as to be capable of reflecting part of the light from an objective lens, and a reflecting surface provided on the objective lens to reflect the reflected light from the field frame to the eyepiece lens to indicate a bright frame within the finder view field. The reflecting surface includes a central area containing the optical axis and passing light therethrough, a boundary area surrounding the central area, and a marginal area surrounding the boundary area and having a reflection factor greater than that of the central area. The boundary area has a reflection factor continuously varying so as to be smaller toward the optical axis and is formed in an annular shape having a width substantially equal to the diameter, on the reflecting surface, of a reflected light beam passing from a point of the field frame to the circumference of the exit pupil of the finder.