Patent ID: 7798970

Claim:
An ultrasonic monitor comprising: a printed circuit board comprising multiple layers, including an outer layer having one or more air gaps which extend in one or more respective sections of the outer layer, the one or more respective sections are removed by chemical etching, and the one or more air gaps have a depth which is at least a thickness of the outer layer; and one or more ultrasonic transducers provided as one or more surface-mounted packages and having one or more respective top surfaces and one or more respective bottom surfaces, the one or more ultrasonic transducers are surface-mounted via the one or more respective bottom surfaces to a surface of the outer layer of the printed circuit board, and extend over the one or more air gaps, wherein the one or more air gaps are positioned between one or more respective exposed portions of the printed circuit board which are exposed by the chemical etching, and the one or more respective bottom surfaces of the one or more ultrasonic transducers.