Patent ID: 8009518

Claim:
An ultrasonic sensor for detecting a first object, comprising: a transmitting device for transmitting ultrasonic wave to the first object, the transmitting device including a first piezoelectric element for emitting the ultrasonic wave and a first acoustic matching member having a transmitting surface, the emitted ultrasonic wave propagated through the first acoustic matching member and being transmitted through the transmitting surface to the first object, the first piezoelectric element being configured as a multilayer piezoelectric element including a plurality of piezoelectric layers and a plurality of electrode layers interleaved with the plurality of piezoelectric layers; a receiving device, arranged in an array with the transmitting device, for receiving the ultrasonic wave reflected from the first object, the receiving device including a second piezoelectric element for detecting the reflected ultrasonic wave and a second acoustic matching member having a receiving surface, the reflected ultrasonic wave being received through the receiving surface and propagated through the second acoustic matching member to the second piezoelectric element; a housing having an inner space for accommodating the transmitting device and the receiving device, the housing having a bottom and an opening portion, the housing being mountable to a second object at the opening portion; a vibration damper interposed between the opening portion of the housing and each of the first and second acoustic matching members to fix the first and second acoustic matching members to the housing, the vibration damper being interposed between the first and second acoustic matching members to reduce a propagation of the ultrasonic wave between the first and second acoustic matching members; and a vibration isolator for partitioning the inner space of the housing and located between the transmitting device and the receiving device to reduce the propagation of the ultrasonic wave between the transmitting device and the receiving device.