Method of detecting over-actuation of MEM device

摘要

A method of detecting an over-actuation condition within a micro electromechanical device is provided. The device is of a type having a support structure and an actuating arm that is movable relative to the support structure as a result of thermal expansion of at least part of the actuating arm due to heat inducing current flow through that part. The method comprises passing a current pulse having a predetermined duration t_p through the part of the actuating arm, detecting the rate of movement of the actuating arm to a predetermined position beyond an operating position of the actuating arm, and determining whether the detected rate is greater than a normal rate for desired actuation of the actuating arm so as to detect the over-actuation condition.