Actuator driving control device and actuator driving control method

摘要

A driving control device (120) controls supply of driving pulses to expand and contract a piezoelectric element (12) so that an expansion rate is different from a contraction rate, to vibrate a driving rod (17) and move a lens (21) frictionally engaging with the driving rod (17) in two directions. The driving control device (120) includes a forward measuring unit (131), a backward movement controlling unit (133), a backward measuring unit (134) and a movement direction determining unit (135). The driving control device can realize an automatic focusing (AF) search with higher accuracy even at the time of low luminance and/or low contrast. The control mechanism for AF searches is based on AF evaluation values in both lens moving directions.