Liquid ejecting head and liquid ejecting apparatus
A liquid ejecting head includes a substrate having pressure chambers in communication with nozzles through which a liquid is ejected, a vibration plate on the substrate, and a piezoelectric actuator including a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction on the vibration plate. The piezoelectric layer of the piezoelectric actuator has an active portion that overlaps the pressure chamber, the first electrode, and the second electrode when viewed in the first direction and a non-active portion that does not overlap at least one of the first electrode and the second electrode when viewed in the first direction. A piezoelectric material forming the piezoelectric layer has a larger crystal grain size in the non-active portion than in the active portion.
1 . A liquid ejecting head comprising:
a substrate having pressure chambers in communication with nozzles through which a liquid is ejected;
a vibration plate on the substrate; and
a piezoelectric actuator including a first electrode, a piezoelectric layer, and a second electrode stacked in a first direction on the vibration plate, wherein
the piezoelectric layer has an active portion that overlaps the pressure chamber, the first electrode, and the second electrode when viewed in the first direction and a non-active portion that does not overlap at least one of the first electrode and the second electrode when viewed in the first direction,
the active portion and the non-active portion are continuously provided in the piezoelectric layer, and
a piezoelectric material forming the piezoelectric layer has a larger crystal grain size in the non-active portion than in the active portion.
2 . The liquid ejecting head according to claim 1 , wherein the crystal grain size of the piezoelectric material forming the piezoelectric layer in the active portion is smaller than or equal to half the crystal grain size of the piezoelectric material forming the piezoelectric layer in the non-active portion.
3 . The liquid ejecting head according to claim 1 , wherein the crystal grain size of the piezoelectric material forming the piezoelectric layer is more varied in the non-active portion than in the active portion.
4 . The liquid ejecting head according to claim 1 , further comprising an orientation control layer that is overlaps the active portion and does not overlap the non-active portion when viewed in the first direction, the orientation control layer being provided between the first electrode and the piezoelectric layer in the active portion.
5 . The liquid ejecting head according to claim 4 , wherein the piezoelectric layer is thicker than the orientation control layer in the first direction.
6 . The liquid ejecting head according to claim 4 , wherein a piezoelectric material forming the orientation control layer has a smaller crystal grain size than the piezoelectric material forming the piezoelectric layer in the active portion.
7 . The liquid ejecting head according to claim 6 , further comprising:
a first seed layer provided between the first electrode and the orientation control layer; and
a second seed layer provided between the orientation control layer and the piezoelectric layer, wherein
the active portion overlaps the first seed layer and the second seed layer when viewed in the first direction, and
the non-active portion overlaps the second seed layer and does not overlap the first seed layer when viewed in the first direction.
8 . The liquid ejecting head according to claim 1 , wherein the active portion includes a first active portion and a second active portion that is closer to the non-active portion than is the first active portion, and
the piezoelectric material forming the piezoelectric layer in the second active portion has a larger crystal grain size than the piezoelectric material forming the piezoelectric layer in the first active portion and has a smaller crystal grain size than the piezoelectric material forming the piezoelectric layer in the non-active portion.
9 . The liquid ejecting head according to claim 8 , wherein a portion of the first electrode that overlaps the second active portion when viewed in the first direction has a thickness increasing from a non-active portion side toward a first active portion side.
10 . The liquid ejecting head according to claim 1 , wherein the pressure chambers are arranged in an arrangement direction, the first electrode is provided individually for the pressure chambers, and the second electrode is shared by the pressure chambers.
11 . The liquid ejecting head according to claim 1 , wherein the pressure chambers are arranged in an arrangement direction, the first electrode is shared by the pressure chambers, and the second electrode is provided individually for the pressure chambers.
12 . The liquid ejecting head according to claim 1 , wherein the pressure chambers are arranged in an arrangement direction, and the piezoelectric layer continuously extends in the arrangement direction over one of the pressure chambers.
13 . The liquid ejecting head according to claim 1 , wherein the pressure chambers are arranged in an arrangement direction, and the active portion and the non-active portion are arranged in a direction perpendicular to both the arrangement direction and the first direction.
14 . The liquid ejecting head according to claim 1 , wherein the pressure chambers are arranged in an arrangement direction, and the active portion and the non-active portion are arranged in the arrangement direction.
15 . A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1 .