The conventional technique for establishing electric connection between the electric contacts of input/output ends of piezoelectric blades and a circuit board generally is accomplished by soldering connection legs. Due to the piezoelectric blades generate vibrations during the conductive condition, the soldered connection legs that anchor the piezoelectric blades on the circuit board restrict the vibration range. Excessive vibration of the piezoelectric blades could tear off the connection legs at the soldering spots. Hence the conventional soldering connection for the connection legs and the piezoelectric blades inhibits the vibration range and reduces the performance. Moreover, connecting the circuit board and the piezoelectric blades by soldering the connection legs makes fabrication process much more troublesome.
In order to remedy the foregoing problems, The U.S. Pat. No. 6,709,285 entitled “Improved piezoelectric blade connection element” provides an electric input leg with an elastic section to connect the electric contact of the input end of the piezoelectric blade. The elastic section has one end extended to form an anchor section to connect to a circuit board and another end extended towards the upper side of the piezoelectric blade to form a retaining section to prohibit the piezoelectric blade from breaking off and also provide a desired electric connection for the piezoelectric blade.
In the cited reference, the elastic section provides a required vibration room for the piezoelectric blade and resolves the problem of limited vibration room and fracturing connection leg occurred to the conventional soldering technique. However, during vibration of the piezoelectric blade, the elastic section and the piezoelectric blade input end tend to create a gap therebetween that would generate a poor electric connection between the conductive element and the piezoelectric blade. If the vibration amplitude is very big, breaking off could happen. Moreover, anchoring of the retaining section of the conductive element needs an extra machining process such as bending or soldering. This increases the fabrication process and cost.
Furthermore, the conventional technique and the cited reference mentioned above have the electric contacts and connection legs exposed. Due to the electric contacts are made of silver, and the connection legs are made of a copper blade, they tend to attract moisture in the air and generate oxidation. This further affects the electric connection.