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.

There is provided a nozzle plate of an inkjet head, the nozzle plate including: a first surface that is bonded to an upper layer substrate by an adhesive; and a second surface in which an opening of a nozzle that ejects an ink is provided. A step is formed at an edge of the first surface.

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 bonding substrate is provided with nozzle communication channels that establish communication between pressure chambers and nozzles. Each nozzle communication channel includes a pair of first inner wall surfaces constituting wall surfaces in a first direction, and a pair of second inner wall surfaces constituting wall surfaces in a second direction being orthogonal to the first direction. At least one of the second inner wall surfaces includes an inclined surface being inclined such that a length of the nozzle communication channel becomes gradually shorter toward the nozzle. An angle of the inclined surface relative to a liquid ejecting surface where the nozzles are opened is smaller than an angle of the first inner wall surface relative to the liquid ejecting surface.

In example implementations, a printhead die is provided. The printhead die includes a substrate, a chamber layer formed on the substrate, a plurality of printing fluid ejection chambers coupled to opposite sides of the chamber layer and along a length of the chamber layer, and a top hat layer formed on the chamber layer and the plurality of printing fluid ejection chambers. The chamber layer includes a void to store printing fluid. The top hat layer includes an initial unsupported top hat layer portion over the void, wherein the initial unsupported top hat layer portion comprises a first end that is narrower than a second end.

An electric current based on electric charge produced on the piezoelectric body changes by going through a first path, a second path, a third path, and a fourth path in this order. On the first path, the electric current becomes larger as the voltage becomes higher. On the second path, the electric current becomes smaller as the voltage becomes higher. On the third path, the electric current becomes larger as the voltage becomes higher. On the fourth path, the electric current becomes smaller as the voltage becomes higher.

A substrate includes a first substrate which has a first substrate through hole, and a second substrate which has a second substrate through hole and directly or indirectly overlaps the first substrate, the first substrate through hole and the second substrate through hole directly or indirectly communicate with each other to form a liquid supply path and a width D1 of an opening portion of the first substrate through hole on a surface of the first substrate closer to the second substrate, a width D2 of an opening portion of the second substrate through hole on a surface of the second substrate closer to the first substrate, a width D3 of an opening portion of the second substrate through hole on a surface of the second substrate farther from the first substrate have a relationship of D1<D2 and D3<D2.

A method for manufacturing a liquid discharge head comprising: a substrate, a protective layer covering at least a part of the substrate, and a laminate member formed on the protective layer, wherein the method comprises steps of: forming the protective layer on at least a part of the substrate; forming the laminate member on the protective layer with a part of the protective layer exposed, the protective layer comprises at least Si and C, a content of oxygen in a bulk of the protective layer is less than 20 atomic % in terms of an element composition ratio, a modified layer with a content of oxygen of 20 atomic % or more in terms of an element composition ratio is present on a surface of the protective layer, and a thickness of the modified layer between the protective layer and the laminate member is 3.40 nm or less.

A method of manufacturing a liquid discharge head includes preparing a first substrate where a discharge port configured to discharge liquid is formed to face a first surface, a concave portion is formed on a side of a second surface opposite to the first surface, and a first liquid flow passage penetrating from the first surface to the second surface is opened inside the concave portion on the side of the second surface, preparing a second substrate including a second liquid flow passage opened on a third surface, and sticking the first substrate and the second substrate to communicate the first liquid flow passage with the second liquid flow passage by bonding a bottom face of the concave portion and the third surface with an adhesive agent.

A substrate with an electrical connection section or a substrate for liquid ejection head comprises a wiring layer, a diffusion prevention layer laid on the wiring layer and a connection member laid on the diffusion prevention layer for establishing an electrical connection to an outside. An insulation layer having a wiring-layer-exposing opening is arranged on the wiring layer and the diffusion prevention layer is arranged in the opening, while the connection member is arranged on the diffusion prevention layer so as to cover an outer peripheral edge of the diffusion prevention layer.