Patent ID: 6954406

Claim:
A method of making a transducer having three or more impedance matched layers comprising: providing a piezoelectric element having a source impedance, Z 0 ; selecting a target medium having a target impedance, Z (N+1) ; defining a number of matching layers, N, wherein N is an integer greater than two; and for each matching layer, J, incremented 1 from three to the defined number of matching layers, N: determining a required impedance according to: Z J =Z 0 [(N+1−J)/(N+1)] Z (N+1) (J/N+1) ; selecting a material for matching layer J having substantially the determined required impedance Z j wherein the selected material for matching layer J has a speed of sound and a wavelength λ J associated with the speed of sound for matching layer J; determining a positive integer value, n j , and a thickness, L j , of the selected material for matching layer J according to: L J =(2n j −1)λ j /4; and applying the matching layer J of thickness L j to the transducer.