Patent ID: 7821872

Claim:
A method for transmitting an ultrasonic wave by using an ultrasonic sensor including a plurality of transmission elements each having a transmission surface for ultrasonic wave transmission, the plurality of transmission surfaces being arranged in an array, the ultrasonic sensor further including a reception element for receiving and sensing the ultrasonic wave reflected by an object, the method comprising: selecting a first combination of transmission elements from among the plurality of transmission elements so that the first combination of transmission elements includes at least two transmission elements adjacent to each other, wherein the ultrasonic sensor is mounted to a vehicle and configured to sense an object existing around the vehicle, the transmission surfaces of the plurality of transmission elements are arranged to form a horizontal row and a vertical row, the horizontal row is parallel to a horizontal direction, which is substantially parallel to a ground, and the vertical row is parallel to a vertical direction, which is substantially perpendicular to the ground, each of the plurality of transmission elements includes a piezoelectric element and an acoustic matching member, each piezoelectric element is configured to oscillate the ultrasonic wave, and the transmission surface is disposed on each acoustic matching member, the transmission surface is exposed and directed to the object, the acoustic matching member of each transmission element conducts the ultrasonic wave oscillated by the piezoelectric element of the each transmission element to the transmission surface so that the ultrasonic wave is sent from the transmission surface; and vibrating the transmission surfaces of the first combination of transmission elements in a substantially same phase so that the transmission surfaces of the first combination vibrate in an integral manner, and thereby, transmitting the ultrasonic wave with a first directivity while preventing vibration conduction between one transmission element and another transmission element by using a vibration damping member that (i) is located between the plurality of transmission elements so as to be proximal to each transmission surface, (ii) damps the ultrasonic wave conducing therethrough, and (iii) has an elasticity smaller than that of the acoustic matching member, wherein each of the plurality of transmission elements is configured to individually vibrate to thereby transmit the ultrasonic wave with a second directivity, and wherein the second directivity is different from the first directivity.