Patent ID: 7728490

Claim:
A capacitive micromachined ultrasonic transducer, comprising: a membrane having a first electrode and a supporting film supporting the first electrode; a second electrode arranged opposite to the supporting film; a membrane supporting part disposed between the membrane and the second electrode thereby forming a plurality of spaces between the membrane and the second electrode; a plurality of transducers cells, having the membrane, the spaces and the second electrode, arranged such that as a distance of each of the transducer cells to a periphery of the ultrasonic transducer decreases, the resonant frequency of each of the transducer cells decreases from a center of the transducer cells to a periphery of the transducer cells; a surface of the membrane on a side of the first electrode being curved in a recessed shape such that a plurality of ultrasonic beams transmitted from the surface of the membrane on the side of the first electrode are in focus; a flexible printed circuit joined to the surface of the membrane; a plurality of slits formed from a side of the second electrode to a side of the membrane supporting part; and a filling material filled into each of the plurality of slits for holding the recessed shape, the filling material maintaining the plurality of slits in a configuration where a width of each slit is larger on the side of the second electrode than on a side of the membrane.