CONTROL METHOD FOR A VOICE COIL MOTOR AND LENS FOCUSING SYSTEM USING THE SAME

摘要

A control method is provided to reduce the spring resonance of a voice coil motor when the coil current of the voice coil motor is changed. Each time a total variation for the coil current to be changed is identified and divided into a plurality of step variations applied one by one with a time step equal to one half of the spring resonant period of the voice coil motor. Due to reduction of the spring resonance, the control method speed up the voice coil motor to a steady state. With this control method, a lens focusing system has a shorter focusing time.