Driver for optical deflector using complex-sinusoidal-wave drive voltages and method for setting the same

摘要

In a driver for driving an optical deflector comprising a mirror (1), a movable body (2) for supporting the mirror, a support body (5) surrounding the movable frame, and a first group of piezoelectric actuators (6a-1, 6a-3, 6b-1, 6b-3) serving as cantilevers and a second group of piezoelectric actuators (6a-2, 6a-4, 6b-2, 6b-4) serving as cantilevers alternating with the first group of piezoelectric actuators, the piezoelectric actuators (6a-1, 6a-2, 6a-3, 6a-4, 6b-1, 6b-2, 6b-3, 6b-4) are folded at every actuator and connected from the support body to the movable body. Each piezoelectric actuator is in parallel with one axis of the mirror. A first drive voltage (VY1) for the first group of piezoelectric actuators having first repeated waves each with a first rising period (T1a, T2a) and a first falling period (T1b, T2b) is generated. One of the first rising period and the first falling period is larger than the other. A second drive voltage (VY2) for the second group of piezoelectric actuators having second repeated waves each with a second falling period (T1a, T2a) corresponding to the first rising period of the first drive voltage and a second rising period (T1b, T2b) corresponding to the first falling period of the first drive voltage is generated. Frequencies of the first and second repeated waves exclude natural frequencies (f01, f02, ··· ) of a mechanically-vibrating system of the mirror with respect to the axis thereof depending upon the piezoelectric actuators.