| 摘要 |
There is provided a piezoelectric film-attached substrate, including a piezoelectric film having a specific thickness, wherein a reflection spectrum shows a relation between a light obtained in such a way that the surface of the piezoelectric film is irradiated with an irradiation light having a specific wavelength and the irradiation light is reflected on the surface of the piezoelectric film, and a light obtained in such a way that the irradiation light is transmitted through the piezoelectric film and is reflected on the surface of the lower electrode, which is the reflection spectrum at least at one point on a center part and an outer peripheral part of the piezoelectric film, and such a reflection spectrum has at least one of the maximum value and the minimum value respectively, wherein the reflectance at least in one maximum value is 0.4 or more.
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