| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite material vibrator which has a small structure not requiring any space not to hinder the vibration and excellent in mechanical strength and hardly causes characteristic variation due to the difference in coefficient of thermal expansion between constituent members during its manufacture or when the ambient temperature varies. SOLUTION: The composite material vibrator 1 is constituted as follows. Over a plate-shaped piezoelectric resonance element 2 made of a material having an acoustic impedance value Z1, plate-shaped holding member 5 and 6 made of a material having an acoustic impedance value Z3 are stacked with reflective layer 3 and 4 made of a material having an acoustic impedance value Z2 interposed therebetween. The relations between the impedance values are Z2<Z1 and Z2<Z3. When the coefficient of thermal expansion in the direction parallel to the surfaces of the reflective layers 3 and 4 is represented by X and that in the direction parallel to the surfaces of the holding members is represented by Y, the sign of the X is opposite to that of Y, or the Y and X have the same sign and the Y is 3% or less that of the X. Alternatively, the Y is about zero. COPYRIGHT: (C)2008,JPO&INPIT
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