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:
Feb. 20, 1990
Filed:
Dec. 09, 1988
Sanyo Electric Co., Ltd., Osaka, JP;
Abstract
In an automatic focusing circuit of a video camera, automatic focusing operation is performed by a focus evaluating value formed in response to a video signal obtained by an image sensing circuit (4). A first focusing motor control circuit (15) controls the rotation of a focusing motor (3) so that a focusing lens (1) is once fixed in the position where the focus evaluating value takes the maximum value. A second focusing motor control circuit (17) changes the focusing motor (3), by a predetermined very small amount, to determine the slope of the focus evaluating value, which change is repeated until inversion of the slope, that is, the maximal point is detected. As a result, the position of the focusing lens is corrected at the maximal point of the focus evaluating value. When the correction amount exceeds a predetermined value, first automatic focusing operation by the first focusing motor control circuit (15) is resumed.