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. 03, 1990
Filed:
Jan. 29, 1985
Applicant:
Inventors:
Assignee:
Seikosha Co., Ltd., , JP;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
G03B / ; G01C / ;
U.S. Cl.
CPC ...
356-1 ; 354403 ;
Abstract
A range finder for use with a still camera and the like, projects an infrared light beam to an object and the light beam reflected from the object is detected by a split photosensor. The photosensor is made up of two photodiodes connected in opposite polarity relationship so that a differential photocurrent produced by the diode pair is amplified. The reflected light beam is tracked so that the photosensor provides a zero output, and the distance to the object is determined from the time needed to detect the zero photosensor output.