To provide a highly reliable piezoelectric element, a piezoelectric actuator, a liquid injection head and a liquid injection device.
The piezoelectric element 100 includes a substrate 10, a lower electrode 20 formed on the substrate 10, a piezoelectric layer 30 formed to cover a side face 34 and an upper surface 32 of the lower electrode 20, and an upper electrode 40 formed to cover the side face 34 and the upper surface 32 of the piezoelectric layer 30. The upper electrode 40 has a first region 40A and a second region 40B on the upper surface 32 of the piezoelectric layer 30. The first region 40A includes at least part of a region overlapping the lower electrode 20 in a plan view. The second region 40B is a region other than the first region 40A, and the first region 40A is thinner than the second region 40B.
Osamu Suzawa
Kazuhiko Miyasaka
Next Patent: METALLIC MASK