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:
Jan. 02, 1979
Filed:
Mar. 17, 1977
Toshihiro Kondo, Kamiishihara, Chofu-shi, Tokyo, JP;
Other;
Fuji Photo Film Co., Ltd., Minami-ashigara, JP;
Abstract
Behind an objective which is axially movable, is provided a beam splitter to divide the light path passing through the objective into two light paths. In one of the light paths on the image plane of the objective is located a prism. Behind the prism is provided a photodetector in the optical path includng the prism. In the optical path which does not have the prism also is provided a photodetector at a position which is optically conjugate with the other photodetector. The output of the photodetectors are connected to an output comparing circuit which is connected to a servomotor for controlling the position of the objective. When the outputs of the two photodetectors are equal to each other, the servomotor is stopped.