| 摘要 |
PURPOSE:To eliminate the occurrence of electromagnetic noise by providing a means which applies specified electric fields to respective piezo-electric strain elements in such a way as to be mutually deviated in phase by one quarter period at an identical frequency between a set of piezo-electric strain elements in side-to-side oscillation elastic boards and the piezo- elctric strain element in a vertical oscillation elastic board, and furthermore in such a way as to be interchangeability deviated in phase by the odd number times of one half period between the piezo-electric strain elements in the side-to-side oscillation elastic boards. CONSTITUTION:A vertical oscillation elastic board 3 and a set of at least two side-to-side oscillation elastic boards 21 and 31 are disposed. The former oscillates up and down, which is equipped with a piezo-electric strain element while being attached on its back surface, and the latter which is interposed in specifically spaced relation, oscillates to the direction normal to the oscillating direction of the vertical oscillation elastic board wherein the boards included are provided with piezo-electric strain elements at least on each one surface of them in spaced relation with the upper surface of the vertical oscillation elastic board while a specified interval maintained. |
