Automatic focusing device

Abstract

Abstract PURPOSE:To efficiently execute a correction, and to obtain a focused state in a short time by deriving a defocus amount which follows a movement of an object, at the time point when an arithmetic operation for the next focusing detection has been ended, setting this arithmetic operation end time point as a target of a follow-up correction, and driving a lens by the derived defocus amount. CONSTITUTION:An integration of a light beam of an object is executed by a CCD image sensor 107, and a data dump by which a data of the integrated object is fetched at every picture element is executed. Subsequently, a time TM1 of a free-run timer at the time when the integration is started, and a count value T1 of an event counter EVTCNT for controlling a lens driving amount at the time when the integration is started, and an integration end time TM2, and a count value T2 of the event counter EVTCNT of this time are read. Thereafter, the data dump, and a focusing detection arithmetic operation are executed, but the greater part of this time is spent for this operation. In this way, from the times TM1, TM2 of the integration start time and the integration end time, the time (TM1+TM2)/2 in the integration center point is calculated, stored in a register, and a lens driving amount extending from the previous integration center to the present integration center is calculated.

Inventors

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

Bibliographic Details