| 摘要 |
<p>PROBLEM TO BE SOLVED: To solve the problem that when two piezoelectric ceramic sheets 2, 3 with different thicknesses which form a stuck structure 1 are stuck through a bonding layer 4, there happens the contraction of a bonding agent, and further happen the deflection of an external periphery of the stuck structure 1 and the waviness of the same depending upon the direction of polarization processing of the piezoelectric ceramic sheets 2, 3. SOLUTION: When a thinner piezoelectric ceramic sheet 2 and a thicker piezoelectric ceramic sheet 3 both forming a stuck structure 1 are stuck via a bonding agent layer 4, the surface roughness of the surface of the thinner piezoelectric ceramic sheet on the opposite side at least to the bonded surface of the same sheet is less than 1μm in terms of arithmetic mean roughness (Ra), and polarization processing is applied to the respective piezoelectric ceramic sheets 2, 3 from the surfaces 2b, 3b on the opposite side to the bonded surfaces 2a, 3a toward the bonded surfaces 2a, 3a.</p> |
