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:
Jun. 21, 1983
Filed:
Feb. 27, 1981
Saburo Numata, Urawa, JP;
Fuji Photo Optical Co., Ltd., , JP;
Abstract
In an optical instrument such as a photographic camera or an endoscope, the focus of an image of the object to be observed or photographed is automatically controlled based on the distance automatically measured. The distance of the object is automatically measured by use of a light source for illuminating the object, a photodetector, an image focusing optical system for focusing the image of the object on the photodetector, and an electric circuitry connected with the photodetector. The intensity of the illumination is periodically changed and the light reflected by the illuminated object received by the photodetector is measured. When the level of the output of the photodetector becomes equal to a predetermined level, a signal is generated to indicate that the brightness of the illuminated object has reached a predetermined level. Since the light intensity of the illumination at this point corresponds to the distance of the object, the distance is thus measured. According to the measured distance, a focusing lens is driven to automatically obtain a focused image.