Patent 7990596 was granted and assigned to Seiko Epson on August, 2011 by the United States Patent and Trademark Office.
A mirror device drive control apparatus adapted to perform drive control of a mirror device having a hysteresis characteristic, includes: a drive section adapted to drive the mirror device with a drive signal; a detection section adapted to detect a displacement of a movable section of the mirror device, and to generate and then output a detection signal corresponding to the detection; a control section adapted to perform control of a frequency of the drive signal so that the movable section is displaced in a predetermined range; and an abnormality detection section adapted to detect abnormal vibration of the movable section during the control by the control section, wherein the abnormality detection section detects, in response to change in frequency of the drive signal, a frequency of an envelope included in the abnormal vibration of the movable section as a beat frequency based on a detection signal of the detection section, and obtains a frequency of the drive signal for performing a restoration process of driving of the mirror device based on the frequency of the drive signal changed and the beat frequency.