| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize an ultrasonic sensor apparatus incorporating an ultrasonic sensor used for both transmission and reception, which can detect a subject with high accuracy even when the subject moves relative thereto. <P>SOLUTION: An ultrasonic sensor (30) of piezoelectric type having a membrane structure (34) has a cover (50) fixed to a board (31) thereof. The cover (50) includes a counter portion (51) disposed apart from and oppositely to the membrane structure (34), forming an enclosed space (90) where gas is sealed in between it and the board (31). Also, one of a pair of adjustment electrodes (70, 71) which cause electrostatic attraction when there is electrical continuity thereto (i.e., electrode 70) is formed in the ultrasonic sensor (30) and the other is formed in the cover (50). The counter portion (51) is brought closer to the membrane structure (34) by the electrostatic attraction, and voltage is applied between the adjustment electrodes (70, 71) while a piezoelectric vibrator (33) at least is in a receiving state, where an opposed interval between the counter portion (51) and the membrane structure (34) is made narrower when in the receiving state than in a transmitting state. <P>COPYRIGHT: (C)2013,JPO&INPIT |
