Patent ID: 8029109

Claim:
A liquid jet head comprising: a flow channel forming plate having a pressure generation chamber to communicate with a nozzle ejecting liquid droplets; and a piezoelectric element provided above one surface of the flow channel forming plate, the piezoelectric element having a lower electrode, a piezoelectric material layer, and an upper electrode, wherein the lower electrode in a region opposite the pressure generation chamber has a width smaller than the width of the corresponding pressure generation chamber, and an upper surface and an end surface of the lower electrode in the region corresponding to the pressure generation chamber are covered with the piezoelectric material layer, an end surface of the piezoelectric material layer forms a sloped surface sloping downward toward the outside, an upper surface and an end surface of the piezoelectric material layer in the region opposite the pressure generation chamber are covered with the upper electrode, and a thickness D 1 of the piezoelectric material layer at a first, substantially horizontal portion of the piezoelectric material layer disposed above the upper surface of the lower electrode and a thickness D 2 of the piezoelectric material layer at the sloped, end surface of the piezoelectric material layer satisfy the relationship D 2 >D 1 .