| 摘要 |
PROBLEM TO BE SOLVED: To provide a substrate with a piezoelectric thin film, by which a decrease in the piezoelectric constant dof a piezoelectric element can be suppressed even after a piezoelectric operation is continuously conducted for a long period, in the piezoelectric element comprising a substrate with a piezoelectric thin film including a Pb-free piezoelectric material.SOLUTION: A substrate 1 with a piezoelectric thin film includes a substrate 10 having a first thermal expansion coefficient, and a piezoelectric thin film 16 deposited in a predetermined deposition condition, having a second thermal expansion coefficient, formed on the substrate, and comprising a potassium sodium niobate represented by general formula of (K, Na)NbOwith a perovskite structure. The substrate 1 provided with the piezoelectric thin film 16 formed thereon has a curvature radius of a warping due to the difference between the first and second thermal expansion coefficients of 10 m or more at room temperature. |
