Automatic focussing device

Abstract

Abstract PURPOSE:To obtain a differential circuit output not affected by periodical variance, by taking the detection period of a differential circuit detecting increase/decrease of a focus voltage as an integer multiple of the variance of focus voltage. CONSTITUTION:A detection signal of an objective status detection circuit 10 is applied to a detected period switching circuit 11. This switching circuit 11 applies a basic detecting period (1V) to a differential circuit 5 to obtain a focus voltage with the detecting period of 1V for focussing. If the focus voltage is fluctuated, the circuit 11 applies a detected period signal in 3V period to the circuit 5 to obtain the focus voltage in the detecting period of 3V for focussing.

Inventors

• 👤 Yoshihiro Todaka
• 👤 Kaoru Yanagawa

Bibliographic Details