Patent ID: 8381594

Claim:
An acoustic transducer used for observing a subject, comprising: a first transducer which transmits, to a subject, a first acoustic primary wave including a first ultrasound and a second acoustic primary wave including a second ultrasound different from the first ultrasound in frequency, in a superimposed manner; and a second transducer which is arranged in a region for receiving a reflected wave which hit and reflected from the subject, the reflected wave being an acoustic secondary wave generated at a part where the first and second acoustic primary waves are superimposed to each other, from among acoustic secondary waves as nonlinear acoustic waves whose frequency components have changed along with propagation of the first and second acoustic primary waves, the second transducer resonating with a frequency component of the acoustic secondary wave for receiving the reflected wave, wherein the first transducer has a first region for transmitting the first acoustic primary wave and a second region for transmitting the second acoustic primary wave, transmissions from the first and second regions being made in phase opposition to each other.