Patent ID: 8562154
Filing Date: 2013-10-22
Classification: B08B,G02B,G03B,H01L,H04N

Abstract:
1. A vibrator driving method of applying an alternating voltage to at least two electromechanical energy conversion elements provided in a vibrator, and thus causing the vibrator to generate standing waves respectively different in order with a predetermined time phase difference, wherein the vibrator has a first vibration mode in which plural nodal lines are arranged in a first direction, a second vibration mode in which the number of nodal lines arranged in the first direction is different from that in the first vibration mode and of which a natural frequency is higher than a natural frequency of the first vibration mode, and a third vibration mode of which a natural frequency is located between the natural frequency of the first vibration mode and the natural frequency of the second vibration mode, the number of nodal lines arranged in the first direction in the third vibration mode is the same as that in the first vibration mode or that in the second vibration mode, and the number of nodal lines arranged in a second direction intersecting with the first direction in the third vibration mode is different from that in the first vibration mode or that in the second vibration mode, and the vibrator is driven on condition that an excitation force in one of the first vibration mode and the second vibration mode in which a difference between the natural frequency thereof and the natural frequency of the third vibration mode is smaller is made larger than an excitation force in the other of the first vibration mode and the second vibration mode in which a difference between the natural frequency thereof and the natural frequency of the third vibration mode is larger.