A piezoelectric actuator is disclosed that may include a insulating layer, individual electrodes, a common electrode, and a piezoelectric layer. The common electrode may include divisional electrodes that are connected with one another. The individual electrodes may be disposed between the insulating layer and the piezoelectric layer while the piezoelectric layer may be disposed between the individual electrodes and the common electrode. Further, the divisional electrodes may be configured to face the individual electrodes.

A water-repellent member includes a base layer formed on the substrate, projections dispersedly arranged on the base layer, a first water-repellent material provided on the base layer in contact with the base layer, and a second water-repellent material provided on the projections in contact with the projections. The first water-repellent material and the second water-repellent material are perfluoropolyether compounds. An oxygen concentration of the base layer is lower than an oxygen concentration of the projections.

Isolation between electrodes is ensured to enhance resistance to a liquid. A conductive film is provided to a surface of a piezoelectric substrate, and laser processing is performed in a groove extending direction on the conductive film between a first groove and a second groove provided to the piezoelectric substrate to thereby form a laser processing area where the conductive film is removed to the surface of the piezoelectric substrate between the first groove and the second groove. In forming the laser processing area, an irradiation operation with a laser is performed along a plurality of laser processing lines extending in the groove extending direction. Further, the irradiation operation with the laser is performed a plurality of times for each of the laser processing lines, and the irradiation operations with the laser performed along the same laser processing line of the plurality of laser processing lines are performed at a time interval from when ending a previous irradiation operation with the laser to when starting a subsequent irradiation operation with the laser.

A microfluidic device has a chamber; a fluidic access channel in fluidic connection with the chamber; a plurality of nozzle apertures in fluidic connection with the chamber; and an actuator, operatively coupled to the fluid containment chamber and configured to cause ejection of drops of fluid through the nozzle apertures in an operating condition of the microfluidic device. The chamber has an elongated shape, with a length and a maximum width, wherein an aspect ratio between the length and the maximum width of the chamber is at least 3:1. The nozzle apertures are configured to generate, in use, a plurality of drops having a total drop volume, wherein a ratio total drop volume to a chamber volume is at least 15%.

A liquid ejection head has at least a structure including an ejection orifice forming member having an ejection orifice for ejecting a liquid and a flow path communicating with the ejection orifice and a flow path forming substrate having a liquid introduction flow path communicating with the flow path and supplying the liquid, and includes: a first titanium oxide film with a pure water contact angle of 40° or less; and a second titanium oxide film with a pure water contact angle of 70° or more, wherein the first titanium oxide film covers the structure including inner walls of the flow path and the liquid introduction flow path and is exposed in the flow path and the liquid introduction flow path, and the second titanium oxide film has a portion covering the first titanium oxide film in a vicinity of an opening end.

A fluid ejection apparatus includes a plurality of fluid ejectors. Each fluid ejector includes a pumping chamber, and an actuator configured to cause fluid to be ejected from the pumping chamber. The fluid ejection apparatus includes a feed channel fluidically connected to each pumping chamber; and at least one compliant structure formed in a surface of the feed channel. The at least one compliant structure has a lower compliance than the surface of the feed channel.

A method for producing a liquid transport apparatus is disclosed. The liquid transport apparatus includes a pressure chamber plate, a ceramics layer formed on a surface of the pressure chamber plate, a piezoelectric layer formed on the ceramics layer, and an electrode formed on the piezoelectric layer. The ceramics layer is formed by heating an insulating ceramic material at a temperature lower than an annealing temperature of the piezoelectric layer. Accordingly, the atoms of the pressure chamber plate are suppressed from being diffused into the piezoelectric layer.

A fluid ejection apparatus includes a plurality of fluid ejectors. Each fluid ejector includes a pumping chamber, and an actuator configured to cause fluid to be ejected from the pumping chamber. The fluid ejection apparatus includes a feed channel fluidically connected to each pumping chamber; and at least one compliant structure formed in a surface of the feed channel. The at least one compliant structure has a lower compliance than the surface of the feed channel.

A piezoelectric device includes a piezoelectric body, a vibration plate that vibrates when the piezoelectric body is driven, a first electrode positioned between the piezoelectric body and the vibration plate, and a second electrode positioned to be separated from the first electrode by the piezoelectric body. The piezoelectric body has an active portion that is a part sandwiched between the first electrode and the second electrode in a first direction along a thickness direction of the piezoelectric body, and a change width of a dC/dV value, which represents a change in capacitance with respect to a change in a voltage applied along a second direction orthogonal to the first direction, from one end of the active portion on a side of the first electrode to the other end of the active portion on a side of the second electrode in the first direction is 10% or less.

A method for producing a silicon substrate comprising a silicon base material; and a wiring formation layer laminated on a base material surface of the silicon base material, and being provided with a wiring member, an electrode member comprising a noble metal, and a close contact member comprising a base metal between the wiring member and the electrode member, wherein the method comprises a step of forming a deposition film by a fluorocarbon gas, in etching of the silicon substrate; and a removal step of removing, by a removal solution, the deposition film formed by the fluorocarbon gas; the removal solution comprises a primary amine and an organic polar solvent; a content of water in the removal solution is 10 mass % or lower; and a content of tetramethylammonium hydroxide in the removal solution is 1 mass % or lower.