Patent ID: 8157740

Claim:
An in-body-cavity diagnostic ultrasound system comprising: a capacitive micromachined ultrasonic transducer (cMUT) obtained by processing a silicon substrate by using a silicon micromachining technique; an oscillator circuit having the cMUT as a capacitor, and outputting a frequency modulation signal obtained by modulating a frequency of an oscillation signal to be output on the basis of a change of capacitance of the cMUT; a switching unit for switching between an electric connection in which a high-frequency pulse signal superposed on DC bias voltage is supplied to the cMUT, and an electric connection between the cMUT and the oscillator circuit; and a demodulation unit for demodulating the frequency modulation signal output from the oscillator circuit, wherein: when receiving ultrasound, the switching unit switches the electric connection such that an electronic connection between the cMUT and the oscillation circuit becomes effective, and when the cMUT receives ultrasound, the oscillation circuit outputs the frequency modulation signal on the basis of a change of capacitance of the cMUT, the demodulation unit includes a local oscillator circuit, a mixing circuit, and a bandpass filter, and a transducer element of the cMUT, the oscillator circuit, the switching unit, and at least one of the local oscillator circuit, the mixing circuit, and the bandpass filter are formed on one and the same semiconductor substrate.