Patent ID: 8870352

Claim:
A piezoelectric device defining an X direction, a Y direction generally transverse to the X direction, and a Z direction generally transverse to the X and Y directions, the piezoelectric device comprising: a substrate disposed at a first layer in the Z direction; a first electrode disposed at a second layer, the second layer being disposed above the first layer in the Z direction, the first electrode being disposed above the substrate in the Z direction; a first piezoelectric element disposed at a third layer, the third layer being disposed above the second layer in the Z direction, the first piezoelectric element being disposed above the first electrode in the Z direction; a low density region disposed at the third layer, alongside the first piezoelectric element in an X-Y plane, wherein the low density region is disposed substantially at a same height in the Z direction as a height in the Z direction of the first piezoelectric element, wherein the low density region has density lower than a density of the first piezoelectric element; a second piezoelectric element which covers the first piezoelectric element and the low density region; and a second electrode disposed above the second piezoelectric element in the Z direction.