PROBLEM TO BE SOLVED: To provide a driving device for an actuator, which is used for an autofocus mechanism of an imaging apparatus, and drives to displace a movable part, by applying current to shape memory alloy and deforming the shape memory alloy, and which attains drive at equal interval steps, by compensating nonlinearity of "displacement (distortion rate)-the resistance value characteristics" of the shape memory alloy, using a simple constitution.;SOLUTION: In a target resistance value setting part 24, when a step operation command is input from a focus arithmetic operation part, a target resistance value of a target resistance value register 31 is updated to a value obtained, by subtracted by a predetermined variation Δ from a variation register 34 by a subtracter 33. The variation Δ is added in an accumulated value addition part 35, in response to the step operation command, as compared with a threshold from a threshold register 37 in a comparator 36 and is decreased, when it exceeds the threshold. Nonlinearity therefore is compensated for with a simple algorithm, by a comparatively small-scale circuit in the driving device which does not have displacement sensor utilizing the resistance value-distortion characteristic which realizes reduction in cost and miniaturization.;COPYRIGHT: (C)2010,JPO&INPIT
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