ULTRASONIC TRANSDUCER AND METHOD

摘要

A probe (11) for measuring precise distances to an object using acoustic energy is disclosed. An ultrasonic transducer (50) generates an ultrasonic signal in response to an electrical stimulus. The probe includes a pair of spaced-apart reference surfaces placed between the transducer (50) and the object for reflecting ultrasonic energy to create an echo. The reference surfaces are spaced a known distance apart. Means is provided for ascertaining the distance to the object by taking a ratio of the time required for the echo from one of the reference surfaces to return to the foil (61) and the time required for an echo to return from the target object so that distances can be precisely determined independent of temperature and other environmental conditions that measure the time of flight. Additionally, the measuring means ascertain the time elapsed between reception of the first and second reference surfaces to precisely determine distance independent of slight variations in the position of transducer foil (61).