Patent ID: 8067877

Claim:
An anti-EMI ultrasonic transducer comprising: a conductive casing having an inside face, inside wall and an opening opposite to the inside face; a piezoelectric ceramic board mounted on the inside face and having: a first electrode face; and a second electrode face being opposite to the first electrode face and mounted on the inside face of the conductive casing; a conductive shelter mounted to the conductive casing to form an EMI shelter for the piezoelectric ceramic board, and comprising: a circular and electronic insulation net having an edge; a circular and electronic insulation ring mounted around the edge of the circular and electronic insulation net; and a metal coating layer formed on an outer surface of the circular and electronic insulation net and ring; multiple signal wires having: a first signal wire electronically insulating to and passing through the conductive shelter and mounted to the first electrode face of the piezoelectric ceramic board, and configured to transmit a first voltage signal with a first potential; and a second signal wire connected to the conductive shelter, and configured to transmit a second voltage signal with a second potential which is lower than the first potential of the first voltage signal; and an encapsulation formed in the conductive casing and sealing the first and second signal wires in the conductive casing, the conductive shelter and the piezoelectric ceramic board.