Automatic focusing device

Abstract

Abstract PURPOSE:To obtain an automatic focusing device which operates stably nearly within its focusing position range without deteriorating in response outside of said near focusing position range. CONSTITUTION:A focus arithmetic controlling circuit 10 processes photoelectric conversion signals of subject images reformed on solid-state image pickup elements 8 and 9 to detect the relative positions of said subject images, and thus obtains pieces of information on a front-focus, a rear-focus, and a focusing state, and the displacement position of a photographic lens from a focusing position, and also drives a motor 13 to output a servo signal x(t) based upon those pieces of information for the movement of the focusing position of the photographic lens 1. This servo signal x(t) contains an improper component (noise) transiently owing to camera shake, noise malfunction of the device, etc. A servo-control circuit 11 inputs the servo signal x(t) containing the noise, and then converts it into a servo signal z(t) removed from the noise to putting the automatic focusing device in stable operation.

Inventors

• 👤 Yosuke Kusaka
• 👤 洋介 日下

Bibliographic Details