| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an acoustic wave device capable of increasing an electromechanical coupling coefficient kthat hardly generates variation of frequency characteristics regardless of variation in thickness of a piezoelectric material.SOLUTION: An acoustic wave device 1 is formed by laminating a medium layer 3, a piezoelectric material 4, and an IDT electrode 5 on a support substrate 2. The medium layer 3 is composed of a medium containing a low speed medium in which a propagation velocity of a bulk wave which is the same as a main vibration component of an acoustic wave is lower than a propagation velocity of the acoustic wave that is used and a high speed medium in which the propagation velocity of the bulk wave that is the same as the main vibration component of the acoustic wave is higher than the propagation velocity of the acoustic wave. A thickness of the medium layer is equal to or more than 1λ, when a period of IDT is denoted asλ.</p> |
