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. 02, 1991
Filed:
May. 29, 1990
Akira Akashi, Yokohama, JP;
Terutake Kadohara, Yokohama, JP;
Ichiro Ohnuki, Kawasaki, JP;
Masaki Higashihara, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Apparatus for use with an autofocus adjusting device which has a focus detecting circuit for detecting a focus state of an imaging optical system, and a driving circuit for driving the imaging optical system in accordance with the detected focus has a calculation circuit for performing a first calculation in which imaging plane positions at a plurality of points of time in the past and in the present time are determined on the basis of a signal representing a focusing state in the past and a signal representing a focusing state at the latest time to determine coefficients of a predetermined higher order function. The calculation circuit also performs a second calculation in which an imaging plane position at a time after a predetermined period of time has past is determined on the basis of the higher order function. A regulation circuit regulates the signal representing the focusing state detected by the focus detecting circuit when the second calculation is performed, and causes the second calculation to be performed on the basis of the regulated signal. A control circuit is provided for transmitting the signal representing the imaging plane position obtained by the calculation circuit to the driving circuit for driving the imaging optical system. This allows proper focus point prediction even when the zoom state of a zoom lens changes.