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.

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 selected from the group consisting of a metal other than iron, silicon, and zirconium, a metalloid, and a semiconductor, as a constituent element, in the second layer and the third layer, a position with a highest concentration of impurities other than the constituent elements of the second layer and the third layer is in the second layer, a position with a highest concentration of zirconium is in the third layer, and a position with a highest concentration of silicon is in the first layer.

A liquid discharge head includes a substrate, a pressure chamber through which a first liquid and a second liquid flow while being in contact with each other, a pressure generating element configured to pressurize the first liquid, and a discharge port configured to discharge the second liquid. The substrate has a first channel and a second channel that each extend through the substrate. The first channel is used to supply the first liquid to the pressure chamber. The second channel is used to supply the second liquid to the pressure chamber. A viscosity of the second liquid is greater than a viscosity of the first liquid. An average cross-section area of the second channel is greater than an average cross-section area of the first channel.

A liquid discharge head including: a substrate having a liquid supply port; a flow channel forming member that is provided on the substrate and has discharge ports for discharging a liquid and a liquid flow channel that makes the liquid supply port and the discharge ports communicate with each other; and a support member that is provided on the substrate and arranged to be in contact with at least one surface of the flow channel forming member, with the one surface not being in contact with the liquid, wherein the flow channel forming member includes a cured product of a first photosensitive resin composition including a photosensitive resin, the support member includes a cured product of a second photosensitive resin composition including the epoxy resin A having a structure represented by formula (a1) or (a2) below in main chain structure: ##STR00001##
where, n.sub.1 and n.sub.2 represent integers of at least 2.

A channel member includes a first substrate in which a channel is formed from a first surface, and a second substrate having a second surface facing the first surface, wherein the first substrate and the second substrate are bonded to each other with an adhesive between the first surface and the second surface, wherein the channel has a polygonal shape when viewed from a direction orthogonal to the first surface, wherein the channel includes a first portion on the first surface side and a second portion that communicates with the first portion, wherein an aperture area of the second portion is larger than an aperture area of the first portion when viewed from the direction orthogonal to the first surface, and wherein the adhesive is present on a step surface between the first portion and the second portion and at vertices of the polygonal shape.

A flow path member includes a first substrate, a second substrate, bonding adhesive, and recessed portions. The first substrate has a first surface formed with an opening of a flow path. The second substrate has a second surface facing the first surface. The bonding adhesive bonds the first and second surfaces together. The recessed portions are formed in at least one of the first surface of the first substrate and the second surface of the second substrate. Each recessed portion is a hole configured to take up excess bonding adhesive and, as a non-through hole, does not extend through the entire thickness of a substrate. Each of the recessed portions extends into the first substrate or the second substrate as a rectangular column or an elliptical column and, when a shape of each recessed portion is viewed from the direction orthogonal to the first surface, the shape is approximately isotropic.

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 shaped object, the method comprising: laminating a photosensitive resin composition on an inorganic material layer of a substrate having the inorganic material layer on a surface thereof; performing a patterned exposure of the photosensitive resin composition using an i-line; and curing a pattern-exposed portion and removing an unexposed portion to form a shaped object in which a cured product of the photosensitive resin composition is formed on the substrate, wherein the photosensitive resin composition comprises an epoxy resin, at least one cationic polymerization initiator with a molar extinction coefficient in an i-line of less than 500 L.Math.mol.sup.−1.Math.cm.sup.−1 and at least one sensitizer with a molar extinction coefficient in an i-line of 500 L.Math.mol.sup.−1.Math.cm.sup.−1 or more.

A liquid ejection head includes a substrate having a liquid feeding port and an energy generating element, a substrate protective layer provided on the substrate, and a nozzle forming member provided on the substrate protective layer, and having an ejection port ejecting a liquid, and a liquid flow channel communicating with the liquid feeding port and the ejection port. The substrate protective layer comprises an ion scavenger.

A substrate having a recessed portion, a diaphragm, and a piezoelectric actuator are provided, the diaphragm includes a first layer containing silicon as a constituent element, and a third layer disposed between the first layer and the piezoelectric actuator and containing zirconium as a constituent element, and a laminated side surface of the first layer and the third layer is covered with a moisture-resistant protective film containing at least one selected from the group made of oxide, nitride, metal, and diamond-like carbon.