A method for manufacturing a bonded substrate, the method includes: bonding a first mother substrate including a first substrate and a second mother substrate including a second substrate to form a bonded mother substrate; cutting off a part of the first mother substrate along a dividing line of the bonded mother substrate to form a cutoff portion; dividing the bonded mother substrate along the dividing line; separating a bonded substrate from the bonded mother substrate, the bonded substrate including the first substrate and the second substrate bonded to the first substrate; forming a contact terminal on an end portion of the first mother substrate, the contact terminal contactable with an external terminal; forming a communication path between the first mother substrate and the second mother substrate along the dividing line.

A piezoelectric actuator includes a piezoelectric layer and a conductor layer that is provided directly or indirectly on the piezoelectric layer. In plan view, the conductor layer includes a plurality of individual electrodes that are arranged with intervals therebetween and a plurality of wiring lines that extend from the plurality of individual electrodes. Each wiring line includes a wide portion and a first narrow portion. The wide portion includes a part positioned at a center of the wiring line in a length direction. The first narrow portion is disposed between the wide portion and one of the plurality of individual electrodes to which the wiring line is connected. The first narrow portion has a width less than a width of the wide portion.

A piezoelectric film includes a plurality of laminated main baking unit PZT layers. A first seed layer is present at a lower surface side of a lowermost main baking unit PZT layer. A second seed layer is interposed between two adjacent main baking unit PZT layers at an intermediate position between the lowermost main baking unit PZT layer and an uppermost main baking unit PZT layer.

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.

A piezoelectric device includes a substrate, a diaphragm; and a piezoelectric actuator, in which the substrate, the diaphragm, and the piezoelectric actuator are laminated in this order in a first direction, the diaphragm includes a first layer containing silicon as a constituent element, a third layer disposed between the first layer and the piezoelectric actuator and containing zirconium as a constituent element, and a second layer disposed between the first layer and the third layer and containing at least one impurity element selected from the group consisting of a metal, a metalloid, and a semiconductor other than silicon and zirconium, as a constituent element, and the impurity element diffuses into the third layer.

An apparatus includes a reservoir and a printhead. The printhead includes a support structure including a deformable portion defining at least a top surface of a pumping chamber, a flow path extending from the reservoir to the pumping chamber to transfer fluid from the reservoir to the pumping chamber, and an actuator disposed on the deformable portion of the support structure. A trench is defined in a top surface of the actuator. Application of a voltage to the actuator causes the actuator to deform along the trench, thereby causing deformation of the deformable portion of the support structure to eject a drop of fluid from the pumping chamber.

An apparatus includes a reservoir and a printhead. The printhead includes a support structure including a deformable portion defining at least a top surface of a pumping chamber, a flow path extending from the reservoir to the pumping chamber to transfer fluid from the reservoir to the pumping chamber, and an actuator disposed on the deformable portion of the support structure. A trench is defined in a top surface of the actuator. Application of a voltage to the actuator causes the actuator to deform along the trench, thereby causing deformation of the deformable portion of the support structure to eject a drop of fluid from the pumping chamber.

Provided are a head device, an ink jet printing device, and a driving voltage adjustment method capable of adjusting a driving voltage corresponding to a target jetting amount and suppressing unevenness of printing density occurring between head modules. A dead device includes an ink jet head including a plurality of head modules, and a driving voltage supply device that includes a processor and supplies a driving voltage to the ink jet head, in which the processor acquires a module characteristic, acquires an ink characteristic of ink applied to printing, derives a first voltage coefficient for adjusting a driving voltage corresponding to a target jetting amount for each head module based on the module characteristic and the ink characteristic, and adjusts the driving voltage by applying the first voltage coefficient for each head module.

A piezoelectric actuator includes a common electrode on a piezoelectric layer at a first side adjacent to a first surface and extends over a plurality of piezoelectric elements. A plurality of first individual electrodes is on the piezoelectric layer at a second side adjacent to a second surface. Each of the plurality of first individual electrodes is at a piezoelectric element of the plurality of piezoelectric elements, and are not electrically connected together. A first insulating layer is on the common electrode at the first side and extends over the plurality of piezoelectric elements. A plurality of second individual electrodes is on the first insulating layer at the first side. Each of the plurality of second individual electrodes is at a piezoelectric element of the plurality of piezoelectric elements, and overlap centers of the plurality of first individual electrodes. The plurality of second individual electrodes are electrically connected together.

There is provided a piezoelectric element including: a substrate; a first electrode formed at a first substrate surface of the substrate in a first direction; a first piezoelectric layer that is formed at the first electrode and that includes a flat surface portion along the first substrate surface and an inclined surface portion inclined with respect to the flat surface portion; a second piezoelectric layer that is formed at the inclined surface portion 170a and whose thickness is smaller than a thickness of the flat surface portion of the first piezoelectric layer; and a second electrode formed at at least the flat surface portion.