A method for producing a liquid discharge apparatus includes: forming a first electrode on a film formed on a substrate, forming a piezoelectric part on the first electrode, forming a second electrode on the piezoelectric part, forming a metal part on the film by a metal material except for gold, and forming a gold trace on the metal part to connect to the first electrode.

Provided are a liquid jet head with which the size-reduction can be achieved, while the resistance of wiring formed on a wiring plate such as a sealing plate is lowered, and a method for manufacturing the liquid jet head. The liquid jet head includes: a sealing plate having a first surface to which a pressure chamber-forming plate including multiple piezoelectric elements is joined and a second surface which is on a side opposite from the first surface and to which a drive IC that outputs signals for driving the piezoelectric elements is joined, wherein a lower surface-side embedded wire connected to a common wire common to the driving elements are formed on the first surface of the sealing plate, and the lower surface-side embedded wire is at least partially embedded in the sealing plate.

A piezoelectric thin film is formed by adding a donor element to lead zirconate titanate. In the piezoelectric thin film, a molar ratio of lead to a total sum of zirconium and titanium is 105% or higher, and, when positive and negative coercive electric fields in polarization and electric field hysteresis are referred to as Ec (+) and Ec (?), respectively, a value of |Ec (+) |/|Ec (?) | is 0.5 or more and 1.5 or less.

An apparatus for a lead-free piezoelectric ink-jet printhead is disclosed. Piezoelectric printheads, while more expensive are favored because they use a wider variety of inks. The piezoelectric printhead includes a diaphragm, a plurality of piezoelectric actuators comprising a lead-free piezoelectric material, at least one nozzle, at least one ink chamber, a top electrode, and a drive circuit. The deflection of the diaphragm on the body chamber contributes to a pressure pulse that is used to eject a drop of liquid from the nozzle. According to an exemplary embodiment, a lead-free piezoelectric printhead operated at smaller thicknesses and significantly higher electric fields is disclosed, along with methods of making such printheads.

A piezoelectric device includes an active portion of a piezoelectric layer interposed between a first electrode and a second electrode is provided independently for each of a first recessed portions, the first electrode forms an individual electrode provided independently for each of the active portions, the second electrode forms a common electrode commonly provided to a plurality of the active portions, in the piezoelectric layer, a second recessed portion which is provided outside the active portion and opens on a side opposite to a substrate is provided, and in a lamination direction of the substrate and the piezoelectric element, a vibration plate has a nitride film as an uppermost layer on the second electrode side at least in a region overlapping a bottom surface of the second recessed portion.

A method for manufacturing a piezoelectric actuator is disclosed that includes forming a vibration plate, forming a plurality of electrodes on the vibration plate, forming a piezoelectric layer on the electrodes, and forming a common electrode on the piezoelectric layer.

A printed circuit board has a first coefficient of thermal expansion. A compound is molded about the printed circuit board. The compound has a second coefficient of thermal expansion different than the first coefficient of thermal expansion. An interface is between an edge of the printed circuit board and the compound. The interface has a third coefficient of thermal expansion between the first coefficient of thermal expansion and the second coefficient of thermal expansion.

A liquid ejection head includes an ejection hole surface where a plurality of nozzles ejecting liquid open. The ejection hole surface includes a nozzle arrangement region where the plurality of nozzles are arranged. Each nozzle includes an inversely tapered part where a cross-sectional area increases toward the ejection hole surface. A first nozzle is arranged at a center part of a predetermined direction of the nozzle arrangement region, while second nozzles are arranged at the end parts at the two sides in the predetermined direction. When viewed from the ejection hole surface side as T, the width of the first nozzle's inversely tapered part is larger than the widths of the inversely tapered parts of the second nozzles. In the nozzle arrangement region, the ejection hole surface includes a shape that the center part in the predetermined direction projects with respect to the end parts on the two sides.

A method for forming a patterned film on a substrate includes: step of patterning a mask material on the substrate, thereby covering, with the mask material, the region except a patterned film forming region on a substrate surface on which the patterned film is to be formed; step of covering, with a protective member, at least a part of the surface of the mask material opposite to the substrate so as to allow the patterned film forming region to communicate with outside air, thereby forming a workpiece to be subjected to film formation in following step; step of forming a film on at least the patterned film forming region of the surface of the workpiece communicating with the outside air; step of releasing the protective member from the mask material; and step of removing the mask material and a part of the film on the mask material.

When the metal constituting a metal layer becoming a diffusion prevention layer is defined as a first metal and the metal constituting a connection terminal is defined as a second metal, in a potential-pH diagram for the first metal-H.sub.2O system, the first metal is present in a passivation area or an insensitive area at a potential of the difference between the standard electrode potentials of the first metal and the second metal in a pH range of 1 to 14.