| 摘要 |
PURPOSE:To reduce burden on a transmitting side and expand the operation margin of a receiving side by using a longitudinal elastic wave as a signal transmitting means between constituting elements and reducing the attenuation of an elastic wave between the transmitting side and the receiving side. CONSTITUTION:On an Si substrate 1, a piezoelectric body 6 is sandwiched by a first electrode 8 and a second electrode 9, the outer side of the substrate is brought into contact with a layer-to-layer insulating layer 7 and piezoelectric elements 13 and 14 which receive a longitudinal elastic wave 16 from the layer-to-layer insulating layer 7 are provided. One element is selected so as to satisfy the following inequality: V1XP1 (V0XP0XnuXp)<1/2>, where the acoustic velocity of the material of the electrode 8, is V1, the density of the material of the electrode 8 is P1, those of the material of the piezoelectric body 6 are V0 and P0 and those of the layer-to-layer insulating film are nu and p. ZnO is used for the piezoelectric body 6, Si glass for the insulating film 7 and Pb, etc., for the electrode 8. Then, the acoustic wave made incident on the layer-to-layer film 7 through the first electrode 8 from the piezoelectric body 6 is sufficiently actuated, the acoustic wave reversely made incident on the piezoelectric body 6 is also sufficiently attenuated and a signal is transmitted between the constitut ing elements using the longitudinal elastic wave. |
