A piezoelectric device includes a first substrate that includes a piezoelectric element (32) provided in a first region where bending deformation is allowed and an electrode layer (39) electrically connected to the piezoelectric element (32), a second substrate in which a bump electrode (43) abutting and conducting the electrode layer (39), and having elasticity is formed, and which is disposed so as to face the piezoelectric element (32) with a predetermined space, and adhesive (43) that bonds the first substrate and the second substrate in a state where a distance between the first substrate and the second substrate is maintained. The adhesive (43) has a width in a center portion in a height direction relative to a surface of the first substrate or the second substrate greater than a width in end portions in the same direction.

According to an example, a base, a diaphragm, and a driving element are provided. The driving element includes a first electrode disposed on a second surface of the diaphragm, a second electrode opposing the first electrode, and a piezoelectric body interposed between the first electrode and the second electrode. In addition, an inter-wiring insulating film that covers the second surface of the diaphragm and the driving element, and an extracting electrode which is on the inter-wiring insulating film, are further provided. The inter-wiring insulating film includes a contact hole that exposes a part of the second electrode and through which the second electrode and the extracting electrode contact each other. The contact hole is disposed at a position which aligned with a solid portion of a circumferential wall of the pressure chamber in the base.

A piezoelectric actuator includes: a plurality of discrete electrodes, which is disposed on one side of a piezoelectric element; a common electrode, which is disposed on the other side of the piezoelectric element; a plurality of discrete contacts, which are respectively connected to the plurality of discrete electrodes, and wherein the plurality of discrete electrodes include: a first discrete electrode; and a second discrete electrode, which is disposed at a position away from a corresponding discrete contact as compared with the first discrete electrode, wherein the common electrode includes: a first common electrode, which faces the first discrete electrode in the thickness direction; and a second common electrode, which is separated from the first common electrode in the surface direction and faces the second discrete electrode in the thickness direction, and wherein a connection wiring is provided to connect the first common electrode with the second common electrode.

A conduction structure includes a device substrate (third substrate) including a conductive portion, an IC (second substrate) including an upper surface, an end surface inclined toward the upper surface, and a conductive portion (second conductive portion), a sealing plate (first substrate) including an upper surface, an end surface (first side wall portion) inclined toward the upper surface, and a conductive portion (first conductive portion), and plating layers that respectively form electrical connections between a conductive portion and a conductive portion and between a conductive portion and the conductive portion.

A piezoelectric device includes an actuator substrate that includes a plurality of piezoelectric element rows having a plurality of piezoelectric elements, and a wiring substrate that is disposed so as to face the actuator substrate. The piezoelectric element rows include a common electrodes common to the plurality of the piezoelectric elements. The actuator substrate includes a plurality of first common wirings connected to each of the common electrodes of the plurality of the piezoelectric element rows. The wiring substrate includes a plurality of second common wirings connected to each of the first common wirings of the plurality of piezoelectric element rows, and a plurality of auxiliary wirings buried in a groove portion formed in the wiring substrate. The auxiliary wirings are connected to each of the second common wirings, and the plurality of auxiliary wirings are not connected to each other.

Provided is a liquid ejection device capable of ejecting a minute liquid droplet with stability, in which a capacity of a pressure chamber facing a second partition portion increases, and a capacity of the pressure chamber facing a first partition portion decreases, at a time when a voltage is applied so that a potential of a first electrode becomes lower than a potential of a second electrode, compared to a time when a voltage is applied so that the potential of the first electrode becomes the same as the potential of the second electrode, the first electrode and the second electrode being included in an electrode formed on each of both side surfaces of partitions.

A method is provided for manufacturing a piezoelectric device including a piezoelectric element that is disposed above a diaphragm and that has a multilayer structure including a first electrode disposed above the diaphragm, a piezoelectric layer disposed on the first electrode, and a second electrode disposed on the piezoelectric layer. The method includes forming the multilayer structure including the first electrode, the piezoelectric layer, and the second electrode above the diaphragm, forming a voltage application electrode extending outwardly from an end of the second electrode to cover a region located above the piezoelectric layer in an inactive section having no second electrode, applying a voltage between the first electrode and the second electrode, and removing the voltage application electrode.

A nozzle plate includes, on a substrate: at least a base layer; an intermediate layer; and a liquid repellent layer. The base layer contains a silane coupling agent A having reactive functional groups at both terminals and including a hydrocarbon chain and a benzene ring at an intermediate part. The intermediate layer contains an inorganic oxide. The liquid repellent layer contains a fluorine (F)-containing coupling agent B.

A liquid discharge head includes an actuator base, a case member, and a nozzle plate. The actuator base includes a plurality of grooves space from each other in a first direction. Each of the grooves extends in a second direction. The actuator base is formed of a piezoelectric ceramic material. The case member includes a frame portion spaced from the actuator base in the second direction. The frame portion has an end surface in the third direction that is level with an end surface of the actuator base in the third direction. The frame portion is formed of a ceramic material having aluminum titanate as a main component. The nozzle plate is contacting the end surface of the frame portion and the end surface of the actuator base.

In order to provide a liquid ejection device capable of ejecting a minute liquid droplet with stability, an end surface of a first partition portion is fixed to a plate with a first adhesive layer, an end surface of a second partition portion is fixed to the plate with a second adhesive layer, and an elastic coefficient of the first adhesive layer is smaller than an elastic coefficient of the second adhesive layer.