Automatic focusing device

Abstract

Abstract PURPOSE:To obtain a focused state in a short time by forecasting a defocus amount which follows a relative movement of an object, and driving a lens so that the defocus amount becomes '0' at an arrival time point. CONSTITUTION:A controller 109 derives a defocus amount ¦DELTA¦ from a data of an image of an object, from an interface circuit 108, based on a data K from a reading circuit 104, and calculates the number of pulses N to be detected by an encoder 113, by an arithmetic operation of K.¦DELTA¦. Also, in accordance with a signal in the defocus direction, which has been derived from the data of the image of the object, a motor MO1 is rotated through a motor driver 114, and at the time point when the pulse being equal to the calculated value N has been inputted to the controller 109 from the encoder 113, it is decided that a focusing lens system has moved by a moving extent DELTAd to a focused position, and the rotation of the motor MO1 is stopped.

Inventors

• 👤 Masataka Hamada
• 👤 正隆 浜田
• 👤 Kenji Ishibashi
• 👤 賢司 石橋
• 👤 Tokuji Ishida
• 👤 石田　徳治

Bibliographic Details