Abstract: There is provided a piezoelectric actuator including a vibration plate; first and second piezoelectric layers; individual electrodes; a first common electrode arranged between the vibration plate and the first piezoelectric layer; a second common electrode arranged between the first piezoelectric layer and the second piezoelectric layer; a first surface electrode which is arranged on the second piezoelectric layer and which is in conduction with the first common electrode; and a second surface electrode which is arranged on the second piezoelectric layer and which is in conduction with the second common electrode. The piezoelectric actuator further comprises an inspection electrode which is arranged on the second piezoelectric layer at an end portion of the second piezoelectric layer, which is overlapped with the one of the first and second common electrodes, and which is not in conduction with any of the individual electrodes, and the first and second common electrodes.

Abstract: There is provided a piezoelectric actuator including: first to fourth piezoelectric layers and first to fifth electrodes. A part, of the first piezoelectric layer, between the first and second electrodes constitutes a first active part. A part, of the second piezoelectric layer, between the second and third electrodes constitutes a second active part. A part, of the third piezoelectric layer, between the third and fourth electrodes constitutes a third active part. Parts, of the first to fourth piezoelectric layers, between the first and fifth electrodes constitute two fourth active parts. A length of the third electrode is longer than a length of the second electrode and a length of the fourth electrode. Parts, of the first and second piezoelectric layers, between the first and third electrodes constitute two non-active parts. Parts, of the third and fourth piezoelectric layers, between the third and fifth electrodes constitute two fifth active parts.

Abstract: A piezoelectric actuator includes a first piezoelectric layer and a first electrode layer disposed on a surface of the first piezoelectric layer. The first electrode layer includes a trunk portion and a plurality of brunch portions branched from the trunk portion. The trunk portion includes a plurality of junction points from each of which a corresponding branch portion of the plurality of branch portions is branched, an end spaced from the plurality of junction points, and a first through hole positioned between the plurality of junction points and the end of the trunk portion. A first mark is positioned inside the first through hole.

Abstract: A liquid discharge head includes a flow passage member, a sealing member, and an actuator member. The flow passage member is formed with individual flow passages each including a nozzle and a pressure chamber and the flow passage member has a surface on which the pressure chamber is open. The sealing member is arranged on the surface and seals the pressure chamber. The actuator member has a piezoelectric layer, a driving electrode, and a high electric potential portion. The piezoelectric layer is adhered to a first surface of the sealing member on a side opposite to the flow passage member, via a first adhesive having an insulating property. The driving electrode is arranged on a side opposite to the sealing member with respect to the piezoelectric layer at a position overlapped with the pressure chamber in a first direction orthogonal to the surface.

Abstract: A piezoelectric actuator includes an electrode layer including a trunk portion and a plurality of branch portions branched from the trunk portion. The trunk portion includes a plurality of junction points from each of which a corresponding branch portion of the plurality of branch portions are branched, an end spaced from the plurality of junction points, and a second through hole positioned between the plurality of junction points and the end of the trunk portion. A plurality of first through holes are grouped into a first group and a second group. The first group overlaps, in a first direction, a particular area defined between the end of the trunk portion and the second through hole and the second group overlaps, in the first direction, another particular area defined between the second through hole and the plurality of junction points.

Abstract: S1 is a sum of the areas of a plurality of individual electrodes formed on a first plane of a piezoelectric body of a liquid discharge head, S2 is an area of a first common electrode formed on a second plane, S3 is an area of a second common electrode formed on a third plane, D1 is a distance between a neutral plane and the first plane in a stacking direction, D2 is the distance between the neutral plane and the second plane in the stacking direction, and D3 is the distance between the neutral plane and the third plane in the stacking direction. Then, D1×S1+D2×S2>D3×S3 is satisfied. The liquid discharge head includes a plurality of conductor layers which are formed on the third plane, without contact with the second common electrode and without contact with each other.

Abstract: There is provided a liquid discharge head including a piezoelectric body having a plurality of individual electrodes and a first common electrode, and a plurality of conductor layers. The plurality of individual electrodes have first to fourth individual electrode arrays, and the first common electrode has first and second extending portions, a plurality of first projecting portions, and a plurality of second projecting portions. Each of the first projecting portions overlaps partially with one of the plurality of individual electrodes forming the second individual electrode array along the stacking direction, and each of the second projecting portions overlaps partially with one of the plurality of individual electrodes forming the third individual electrode array along the stacking direction.

Abstract: A liquid discharge head includes a flow passage member, a sealing member, and an actuator member. The flow passage member is formed with individual flow passages each including a nozzle and a pressure chamber and the flow passage member has a surface on which the pressure chamber is open. The sealing member is arranged on the surface and seals the pressure chamber. The actuator member has a piezoelectric layer, a driving electrode, and a high electric potential portion. The piezoelectric layer is adhered to a first surface of the sealing member on a side opposite to the flow passage member, via a first adhesive having an insulating property. The driving electrode is arranged on a side opposite to the sealing member with respect to the piezoelectric layer at a position overlapped with the pressure chamber in a first direction orthogonal to the surface.

Abstract: There is provided piezoelectric actuator including: vibration plate; first and second piezoelectric layers; a plurality of individual electrodes arranged on actuator surface, of the second piezoelectric layer, on first side in first direction of the second piezoelectric layer; first and second common electrodes; first surface electrode arranged on the actuator surface at an end portion in second direction orthogonal to the first direction; second surface electrode arranged on the actuator surface; and non-conductive electrodes arranged at end portions in the second direction of at least two of the actuator surface, and the first and second boundary surfaces, and which are not in conduction with any of the individual electrodes, and the first and second common electrodes. The non-conductive electrodes are arranged at least in an area of an end portion in the second direction of a stack of the vibration plate, and the first and second piezoelectric layers.

Abstract: There is provided a piezoelectric actuator including a vibration plate; first and second piezoelectric layers; individual electrodes; a first common electrode arranged between the vibration plate and the first piezoelectric layer; a second common electrode arranged between the first piezoelectric layer and the second piezoelectric layer; a first surface electrode which is arranged on the second piezoelectric layer and which is in conduction with the first common electrode; and a second surface electrode which is arranged on the second piezoelectric layer and which is in conduction with the second common electrode. The piezoelectric actuator further comprises an inspection electrode which is arranged on the second piezoelectric layer at an end portion of the second piezoelectric layer, which is overlapped with the one of the first and second common electrodes, and which is not in conduction with any of the individual electrodes, and the first and second common electrodes.

Abstract: An inkjet head includes a channel unit and a piezoelectric actuator. The piezoelectric actuator includes a first piezoelectric plate, a first electrode, a second piezoelectric plate, a second electrode, and a conductive member. The first piezoelectric plate includes a first surface. The first electrode is disposed on the first surface, and includes a first extending portion. The second piezoelectric plate includes a second surface. The second electrode is disposed on the second surface, and includes a second extending portion. The conductive member includes a first conductive portion and a second conductive portion. The first conductive portion is disposed on the first surface. The second conductive portion is disposed on the second surface. The conductive portion covers, in a first direction, a spacing that is located between the first extending portion and the second extending portion in a second direction.

Abstract: A liquid discharge head includes: a piezoelectric body including piezoelectric layers stacked in a stacking direction, the piezoelectric body including a first end and a second end that are separated in a first direction orthogonal to the stacking direction of the piezoelectric layers; individual electrodes positioned in a first plane orthogonal to the stacking direction; a first common electrode formed in a second plane that is orthogonal to the stacking direction and of which position in the stacking direction is different from a position of a neutral plane of the piezoelectric body in the staking direction and a position of the first plane in the staking direction; and a trace positioned in a third plane of which position in the stacking direction is different from a position of the first plane, the position of the second plane, and the position of the neutral plane.

Abstract: There is provided a liquid discharge head including a channel member including: a nozzle surface in which a plurality of first nozzles and second nozzles are opened; first and second common channels; and a film member including a first surface and a second surface. The second surface includes a first recess overlapping with the first common channel in the third direction, and a second recess overlapping with the second common channel in the third direction. A length of the first recess in the second direction is different from a length of the second recess in the second direction.

Abstract: A piezoelectric actuator includes a first piezoelectric layer and a first electrode layer disposed on a surface of the first piezoelectric layer. The first electrode layer includes a trunk portion and a plurality of brunch portions branched from the trunk portion. The trunk portion includes a plurality of junction points from each of which a corresponding branch portion of the plurality of branch portions is branched, an end spaced from the plurality of junction points, and a first through hole positioned between the plurality of junction points and the end of the trunk portion. A first mark is positioned inside the first through hole.

Abstract: A piezoelectric actuator includes an electrode layer including a trunk portion and a plurality of branch portions branched from the trunk portion. The trunk portion includes a plurality of junction points from each of which a corresponding branch portion of the plurality of branch portions are branched, an end spaced from the plurality of junction points, and a second through hole positioned between the plurality of junction points and the end of the trunk portion. A plurality of first through holes are grouped into a first group and a second group. The first group overlaps, in a first direction, a particular area defined between the end of the trunk portion and the second through hole and the second group overlaps, in the first direction, another particular area defined between the second through hole and the plurality of junction points.

Abstract: An inkjet head includes a channel unit and a piezoelectric actuator. The piezoelectric actuator includes a first piezoelectric plate, a first electrode, a second piezoelectric plate, a second electrode, and a conductive member. The first piezoelectric plate includes a first surface. The first electrode is disposed on the first surface, and includes a first extending portion. The second piezoelectric plate includes a second surface. The second electrode is disposed on the second surface, and includes a second extending portion. The conductive member includes a first conductive portion and a second conductive portion. The first conductive portion is disposed on the first surface. The second conductive portion is disposed on the second surface. The conductive portion covers, in a first direction, a spacing that is located between the first extending portion and the second extending portion in a second direction.

Abstract: There is provided a liquid discharge head, including: a piezoelectric body having a plurality of piezoelectric layers stacked on top of each other in a stacking direction; individual electrodes; and a first common electrode. Each of the individual electrodes has a first portion and a second portion arranged in the first direction at an interval, and a third portion coupling the first portion with the second portion. The first common electrode includes a first extending portion as well as first protrusions and second protrusions protruding from the first extending portion. Portions of the first extending portion overlapping in the stacking direction with the third portions are formed having through holes passing through the first common electrode in the stacking direction.

Abstract: There is provided a liquid discharge head including a channel member including: a nozzle surface in which a plurality of first nozzles and second nozzles are opened; a first and second common channels; and a film member including a first surface and a second surface. The second surface includes a first recess overlapping with the first common channel in the third direction, and a second recess overlapping with the second common channel in the third direction. A length of the first recess in the second direction is different from and a length of the second recess in the second direction.

Abstract: There is provided a liquid discharge head, including: a piezoelectric body having a plurality of piezoelectric layers stacked on top of each other in a stacking direction; individual electrodes; and a first common electrode. Each of the individual electrodes has a first portion and a second portion arranged in the first direction at an interval, and a third portion coupling the first portion with the second portion. The first common electrode includes a first extending portion as well as first protrusions and second protrusions protruding from the first extending portion. Portions of the first extending portion overlapping in the stacking direction with the third portions are formed having through holes passing through the first common electrode in the stacking direction.

Abstract: There is provided a liquid discharge head including: a piezoelectric body, a common electrode, a bypass trace, and a plurality of individual electrodes. The piezoelectric body is provided with: a first through hole extending in a stacking direction between a conductive layer constructing the piezoelectric body and a first extending portion of the common electrode, and a second through hole extending in the stacking direction between the conductive layer and the first extending portion. The conductive layer and the first extending portion are electrically connected to each other by a conductive material arranged in the first and second through holes.