Actuator, liquid discharge head, liquid discharge apparatus, and method of manufacturing actuator

Abstract

An actuator includes a substrate, a diaphragm, and a nozzle forming film. The substrate has a liquid chamber. The diaphragm is laminated over the substrate. The nozzle forming film has a nozzle to discharge liquid in the liquid chamber from the nozzle. The nozzle forming film includes a piezoelectric element including a first electrode, a piezoelectric body, and a second electrode; a first wiring; a second wiring; an insulating film; and a protective film. The first wiring is connected to the first electrode. The second wiring is connected to the second electrode. The insulating film electrically insulates the second wiring from the first electrode and the piezoelectric body. The insulating film has an opening at a portion facing a central portion of the second electrode to expose the central portion from the insulating film. The protective film covers the piezoelectric element including the central portion exposed from the opening.

Description

FN202501220[DESCRIPTION][Title of Invention]ACTUATOR, LIQUID DISCHARGE HEAD, LIQUID DISCHARGE APPARATUS, AND METHOD OF MANUFACTURING ACTUATOR[Technical Field]

[0001] The present disclosure relates to an actuator, a liquid discharge head, a liquid discharge apparatus, and a method of manufacturing the actuator.[Background Art]

[0002] In the related art, an actuator includes: a diaphragm that is laminated on a substrate where a liquid chamber has been formed, and constitutes a part of a wall surface of the liquid chamber; a piezoelectric element that includes a first electrode laminated on a surface of the diaphragm on a side opposite a side constituting the wall surface of the liquid chamber, a piezoelectric body laminated on the first electrode, and a second electrode laminated on the piezoelectric body; an insulating film that electrically insulates a wiring that is led out from at least the second electrode from the piezoelectric body and the first electrode; and a protective film that protects the piezoelectric element from moisture.[Citation List][Patent Literature]

[0003] [PTL 1]Japanese Unexamined Patent Application Publication No. 2023-133007[Summary of Invention][Technical Problem]

[0004] PTL 1 describes, as the actuator, an actuator in which an entire piezoelectric element is covered with the insulating film (first insulating film), and a wiring formed on the insulating film and the piezoelectric element are covered with the protective film having electrical insulation property (second insulating film).However, in PTL 1, since the entire piezoelectric element is covered with the insulating film and the protective film, the vibration displacement of the piezoelectric element may be low.[Solution to Problem]

[0005] An actuator includes a substrate, a diaphragm, and a nozzle forming film. The substrate has a liquid chamber. The diaphragm is laminated over the substrate. The diaphragm has a first face having a vibration region facing the liquid chamber and defining a part of a wall of the liquid chamber, and a second face opposite the first face. The nozzle forming film has a nozzle to discharge a liquid in the liquid chamber from the nozzle. The nozzle forming film includes a piezoelectric element, a first wiring, a second wiring, an insulating film, and aFN202501220protective film. The piezoelectric element includes a first electrode over the second face of the diaphragm, a piezoelectric body over the first electrode, and a second electrode over the piezoelectric body. The first wiring is connected to the first electrode. The second wiring partially covers the piezoelectric element and is connected to the second electrode. The insulating film covers a part of the piezoelectric element to electrically insulate the second wiring from the first electrode and the piezoelectric body. The insulating film has an opening at a portion facing a central portion of the second electrode to expose the central portion from the insulating film. The protective film covers the piezoelectric element including the central portion of the second electrode exposed from the opening.In addition, a method of manufacturing an actuator includes forming a liquid chamber in a substrate and laminating a diaphragm over the substrate. The diaphragm has a first face facing the liquid chamber and defining a part of a wall of the liquid chamber, and a second face opposite the first face. The method further includes laminating a first electrode of a piezoelectric element over the second face of the diaphragm, laminating a piezoelectric body of the piezoelectric element over the first electrode, laminating a second electrode of the piezoelectric element over the piezoelectric body, forming an insulating film covering the piezoelectric element, forming a first wiring to connect the first wiring to the first electrode after forming the insulating film, and forming a second wiring partially covering the piezoelectric element to connect the second wiring to the second electrode after forming the insulating film. The second wiring is electrically insulated from the first electrode and the piezoelectric body by the insulating film. The method further includes removing a part of the insulating film covering the piezoelectric element after forming the first wiring and the second wiring and forming a protective film entirely covering the piezoelectric element.[Advantageous Effects of Invention]

[0006] According to one aspect of the present disclosure, a decrease in vibration displacement of a piezoelectric element can be prevented.[Brief Description of Drawings]

[0007] A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings.FIG. 1 is a schematic cross-sectional view of a nozzle vibration type liquid discharge head. FIG. 2 is a schematic perspective view of the liquid discharge head of FIG. 1.FIG. 3 is an enlarged cross-sectional view of a portion X in FIG. 1.FIG. 4 is a diagram illustrating formation regions of an insulating film and a protective film. FIG. 5 is a schematic diagram of a configuration in which an insulating film covers the entire piezoelectric element and a protective film covers a part of the piezoelectric element.FIGS. 6A and 6B are diagrams illustrating a step of forming a diaphragm on a channel substrate.FN202501220FIGS. 7A and 7B are diagrams illustrating a step of forming a piezoelectric element on a diaphragm.FIGS. 8 A and 8B are diagrams illustrating a step of forming an insulating film.FIGS. 9A and 9B are diagrams illustrating a step of forming lead-out wirings.FIGS. 10A and 10B are diagrams illustrating a step of forming an insulating film opening. FIGS. 11A and 1 IB are diagrams illustrating a step of forming a protective film.FIGS. 12A and 12B are diagrams illustrating etching processing of the protective film.FIG. 13 is a diagram illustrating a step of forming a nozzle forming portion.FIG. 14 is a diagram illustrating a step of forming a nozzle.FIG. 15 is a diagram illustrating a step of forming a pad opening.FIGS. 16A and 16B are diagrams illustrating a step of forming a pressure chamber.FIG. 17 is a schematic diagram illustrating a configuration of a unimorph piezoelectric liquid discharge head including an actuator.FIG. 18 is a diagram schematically illustrating a printer that is an inkjet recording apparatus as a liquid discharge apparatus.FIG. 19 is a schematic plan view of a head unit of the printer of FIG. 18.FIG. 20 is a schematic plan view of a part of a printer.FIG. 21 is a schematic side view of the part of the printer of FIG. 20.FIG. 22 is a schematic plan view of a part of a liquid discharge unit.FIG. 23 is a schematic front view of another liquid discharge unit.The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views.[Description of Embodiments]In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.Referring now to the drawings, embodiments of the present disclosure are described below. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0008] Embodiments of the present disclosure are described below with reference to the drawings. It is to be understood that those skilled in the art can easily modify and change the present disclosure within the scope of the appended claims to form other embodiments, and these modifications and changes are included in the scope of the appended claims. The following embodiments are illustrative and do not limit the scope of the appended claims.

[0009] FN202501220A liquid discharge head of a nozzle plate vibration type changes pressure in a pressure chamber, which serves as a liquid chamber, by an actuator including a nozzle, to discharge liquid in the pressure chamber from the nozzle. The nozzle plate vibration type discharges the droplets of the liquid with a smaller force than a typical unimorph piezoelectric head (liquid discharge head that vibrates a face opposed to the face having the nozzle of the pressure chamber to discharge liquid). Thus, the nozzle plate vibration type can achieve power saving of an actuator.

[0010] The increased nozzle density limits a space for laying out a wiring for voltage application, and thus, it is difficult to install the wiring on the surface of a substrate. By constructing the wirings and a drive circuit in the substrate, the wiring can be laid out even in a configuration having a high nozzle density. Typically, lead zirconate titanate (PZT) is common in a material of a piezoelectric element because of its excellent piezoelectric property, but a film formation / crystallization temperature of PZT is 600°C or higher. When PZT is used as the material of the piezoelectric element, the drive circuit and the wiring in the substrate do not withstand the high temperature, and thus, a piezoelectric material having the film formation temperature lower than that of PZT is preferable. In this case, a material having lower piezoelectric property than the PZT is selected. However, as described above, the nozzle plate vibration type can discharge the droplets of liquid with a smaller force than the typical unimorph piezoelectric head (liquid discharge head that vibrates a face opposed to the face having a communication port communicating with the nozzle of the pressure chamber to discharge liquid). Thus, even when a material having lower piezoelectric property than PZT is selected, the droplets of liquid can be discharged satisfactorily.Accordingly, even a piezoelectric material such as a non-lead material having a low film formation / crystallization temperature but low power can be used to discharge the droplets of liquid satisfactorily. As a result, the wiring and the drive circuit can be constructed in the substrate, and high nozzle density can be achieved. Further, the nozzle plate vibration type can reduce the volume of the pressure chamber, and thus, the head can be downsized.

[0011] FIG. 1 is a schematic cross-sectional view of a liquid discharge head 1 of the nozzle plate vibration type. FIG. 2 is a schematic perspective view of the liquid discharge head 1.The liquid discharge head 1 includes an actuator 110, a channel substrate 100 which serves as the substrate, and a frame 120.

[0012] The actuator 110 has a thin film shape and includes a diaphragm 103, multiple nozzles 2 to discharge liquid, and a piezoelectric element 5 which has an annular shape and is disposed around each of the nozzles 2. The channel substrate 100, which serves as the substrate, has multiple pressure chambers 4 (may be referred to as individual liquid chambers), which serve as liquid chambers and each communicate with corresponding one of the multiple nozzles 2.FN202501220The frame 120 has a common liquid chamber 3 communicating with the multiple pressure chambers 4.

[0013] An electrical connection pad 6 for electrically connecting to an electrical component such as an external power supply is disposed at each end of the liquid discharge head 1.

[0014] FIG. 3 is an enlarged cross-sectional view of a portion X of the liquid discharge head 1 of FIG. 1. The diaphragm 103 is formed on the channel substrate 100. As a material of the diaphragm 103, for example, a metal oxide such as silicon dioxide (S iOa), silicon nitride (SiN), or zirconium oxide (ZrO), a semiconductor such as silicon carbide (SiC) or gallium arsenide (GaAs), or a resin can be used. The material preferably has a low Young's modulus to increase the displacement of the diaphragm 103, and in consideration of the difference in linear expansion coefficient between the material of the diaphragm 103 and the material of the channel substrate 100, SiOi having a small difference in linear expansion coefficient relative to that of the channel substrate 100 is preferable as the material of the diaphragm 103. In addition, from the viewpoint of cost, SiOi is preferable as the material of the diaphragm 103.

[0015] The actuator 110 has a nozzle forming portion (film) 111 that covers the piezoelectric element 5. The multiple nozzles 2 are formed in the nozzle forming portion 111. A liquid-repellent film may be formed on a nozzle face of the nozzle forming portion 111. The liquid-repellent film on the nozzle face prevents liquid from adhering to the nozzle face. Thus, liquid discharged from the nozzle 2 can be prevented from being affected by liquid adhering to the nozzle face. When the solvent of the liquid is aqueous, perfluorodecyltrichlorosilane or perfluorooctyltrichloro silane can be used as the material of the liquid-repellent film. A pad opening 10 is formed at an end of the nozzle forming portion 111, and the electrical connection pad 6 is connected to an external electrical component via the pad opening 10.

[0016] The piezoelectric element 5 of the actuator 110 includes a first electrode 51 which may be referred to as a lower electrode, a piezoelectric film 52 which serves as a piezoelectric body, and a second electrode 53 which may be referred to as an upper electrode. In the following description, the first electrode 51 and the second electrode 53 may be collectively referred to as electrodes 51 and 53. A portion of the first electrode 51 on which the piezoelectric film 52 is not laminated, a portion of the piezoelectric film 52 on which the second electrode 53 is not laminated, and an edge of the second electrode 53 are covered with an insulating film 8.

[0017] The insulating film 8 electrically insulates a second lead-out wiring 9b, which is led out from at least the second electrode 53, from the piezoelectric film 52 and the first electrode 51. As a material of the insulating film 8, an oxide of any of silicon (Si), tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), and tungsten (W) can be used. Nitrides of any of silicon (Si), tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), andFN202501220tungsten (W) can also be used. The insulating film 8 may include the multiple oxides and nitrides.

[0018] As with the diaphragm 103, the insulating film 8 preferably has a small Young's modulus, and a linear expansion coefficient close to a linear expansion coefficient of the material of the other components. Accordingly, SiC is preferable as with the diaphragm 103. In addition, reliability can be enhanced by using a dense metal oxide or the nitride as the insulating film 8. Preferably, the insulating film 8 is extremely thinned when the metal oxide or the nitride is used because the metal oxide or the nitride is hard.

[0019] A portion of the insulating film 8 corresponding to the central portion of the second electrode 53 of the piezoelectric element 5 is removed to form an insulating film opening 8a, and thus the central portion of the second electrode 53 of the piezoelectric element 5 is a region not covered with the insulating film 8 (i.e., a portion exposed from the insulating film 8).

[0020] The insulating film 8 has a hole- shaped first contact 7a for electrically connecting the first electrode 51, and a hole- shaped second contact 7b for electrically connecting the second electrode 53. On the insulating film 8, a first lead-out wiring 9a (i.e., a first wiring) led out from (connected to) the first electrode 51 of the piezoelectric element 5 and the second lead-out wiring 9b (i.e., a second wiring) led out from (connected to) the second electrode 53 of the piezoelectric element 5 are formed.

[0021] The first lead-out wiring 9a led out from the first electrode 51 is extended to one end of the liquid discharge head 1, the second lead-out wiring 9b is extended to the other end of the liquid discharge head 1, and the terminal of the first lead-out wiring 9a and the terminal of the second lead-out wiring 9b are exposed to the outside to form the electrical connection pads 6.

[0022] The electrical connection pads 6 may be formed on both ends of a protective film 11 covering the first lead-out wiring 9a and the second lead-out wiring 9b, and the first lead-out wiring 9a and the second lead-out wiring 9b may be electrically connected to the electrical connection pads 6 on the protective film 11 via hole-shaped contacts formed at both ends of the protective film 11. In the following description, the first lead-out wiring 9a and the second lead-out wiring 9b may be collectively referred to as the lead-out wirings 9a and 9b.

[0023] The first lead-out wiring 9a, the second lead-out wiring 9b, and the piezoelectric element 5 are covered with the protective film 11 having moisture-proof property. As a result, moisture which has entered the nozzle forming portion 111 made of resin can be prevented from entering the first lead-out wiring 9a, the second lead-out wiring 9b, and the piezoelectric element 5. Accordingly, corrosion of each lead-out wiring and short circuit can be prevented.

[0024] FN202501220The protective film 11 preferably has electrical insulation property. When the protective film 11 has both electrical insulation property and moisture-proof property, the actuator 110 can be made thinner than in a case where an insulating film is formed under the protective film 11. As a result, such a configuration facilitates the deformation of the diaphragm 103 and enhances vibration efficiency.

[0025] As the protective film 11, silicon nitride (SiN), which is common in a material of a moisture-proof film for semiconductor, is preferable so that the protective film 11 can have both electrical insulation property and moisture-proof property. In addition, as a material of the protective film 11, an oxide of aluminum (Al), tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), or tungsten (W), which is easily formed in a dense film by atomic layer deposition (ALD), can be used. The protective film 11 may be a metal nitride of aluminum (Al), tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), or tungsten (W). The protective film 11 may include the multiple metal oxides and nitrides described above.

[0026] FIG. 4 is a diagram illustrating formation regions of the insulating film 8 and the protective film 11. A hatched portion in FIG. 4 indicates a formation region of the insulating film 8, and a gray portion with dot screen in FIG. 4 indicates a formation region of the protective film 11. As illustrated in FIG. 4, a portion of the insulating film 8 corresponding to the central portion of the second electrode 53 of the piezoelectric element 5 is removed to form the insulating film opening 8a, and thus the central portion of the second electrode 53 of the piezoelectric element 5 is a region not covered with the insulating film 8. Accordingly, the portion of the first electrode 51 on which the piezoelectric film 52 is not laminated, the portion of the piezoelectric film 52 on which the second electrode 53 is not laminated, and the edge of the second electrode 53 are covered with the insulating film 8, and the central portion of the second electrode 53 is a region that is not covered with the insulating film 8. The protective film 11 covers the piezoelectric element 5, the first lead-out wiring 9a, and the second lead-out wiring 9b entirely.

[0027] As described above, a part of the piezoelectric element 5 is not covered with the insulating film 8. As a result, the vibration displacement of the piezoelectric element 5 can be increased as compared with a case where the entire piezoelectric element 5 is covered with the insulating film 8 and the protective film 11. Accordingly, even when a piezoelectric material such as a non-lead material having a low film formation / crystallization temperature but low power is used as the piezoelectric material, the piezoelectric element 5 is vibrated and displaced satisfactorily. As a result, the diaphragm 103 can be vibrated satisfactorily, and the discharge efficiency of droplets of liquid (liquid droplets) can be enhanced.

[0028] FN202501220Since the piezoelectric film 52 of the piezoelectric element 5 is displaced in a lamination direction of the first electrode 51, the piezoelectric film 52, and the second electrode 53, a region not covered with the insulating film 8 is disposed on the second electrode 53, allowing the piezoelectric element 5 to be vibrated and displaced satisfactorily.

[0029] As illustrated in FIG. 5, according to a comparative example, the insulating film 8 may cover the entire piezoelectric element 5, and the protective film 11 may cover only the lead-out wirings 9a and 9b. Such a configuration can reduce the number of films covering the piezoelectric element 5 from two layers to one layer and can increase the vibration displacement of the piezoelectric element 5. However, in such a configuration illustrated in FIG. 5, moisture which has entered the nozzle forming portion 111 may enter from an interface XI between the insulating film 8 and the protective film 11 around the first contact 7a connecting the first electrode 51 and the first lead-out wiring 9a and an interface X2 between the insulating film 8 and the protective film 11 around the second contact 7b connecting the second electrode 53 and the second lead-out wiring 9b. As a result, the moisture which has entered from the interfaces XI and X2 may cause corrosion of the lead-out wirings 9a and 9b and the electrodes 51 and 53 of the piezoelectric element 5 or short circuit.

[0030] On the other hand, in the present embodiment, the insulating film 8 covers only a part of the piezoelectric element 5, and the protective film 11 covers the piezoelectric element 5, the first lead-out wiring 9a, and the second lead-out wiring 9b entirely. As a result, an interface between the protective film 11 and other films is not formed in the vicinity of the piezoelectric element 5 or in the vicinity of each of the lead-out wirings 9a and 9b. Thus, corrosion of the lead-out wirings 9a and 9b and the electrodes 51 and 53 of the piezoelectric element 5 due to moisture can be reliably prevented. Accordingly, a decrease in the vibration displacement of the piezoelectric element 5 can be prevented, the piezoelectric element 5 can be stably driven over time, and the actuator 110 with high reliability can be obtained.

[0031] The portion of the first electrode 51 on which the piezoelectric film 52 is not laminated and the portion of the piezoelectric film 52 on which the second electrode 53 is not laminated are covered with the insulating film 8, and thus, the second lead-out wiring 9b formed on the insulating film 8 can be electrically insulated from the piezoelectric film 52 and the first electrode 51 with high reliability. As a result, the piezoelectric element 5 can be stably driven. In addition, the insulating film 8 is not completely removed from above the second electrode 53, and covers a part of an edge of the second electrode 53 on one side close to the nozzle 2 and a part of an edge on the other side opposite the one side. With such a configuration, the portion of the piezoelectric film 52 on which the second electrode 53 is not laminated and the portion of the first electrode 51 on which the piezoelectric film 52 is not laminated can be reliably covered with the insulating film 8.FN202501220

[0032] The insulating film 8 has a film thickness of several hundred nanometers to several micrometers. The electrical insulation property increases with an increase in the film thickness to enhance reliability, but the vibration displacement of the piezoelectric element and the discharge efficiency of liquid droplets decrease with an increase in the film thickness. However, as in the present embodiment, the insulating film opening 8a allows the piezoelectric element 5 to increase the vibration displacement as compared with the case where the entire piezoelectric element 5 is covered with the insulating film 8. Accordingly, the insulating film opening 8a can increase the vibration displacement, and thus the film thickness of the insulating film 8 in the portion of the first electrode 51 on which the piezoelectric film 52 is not laminated and the portion of the piezoelectric film 52 on which the second electrode 53 is not laminated can be thickened by the increase amount of the vibration displacement. As a result, the electrical insulation property can be enhanced while the discharge efficiency of liquid droplets is kept the same as in the comparative example.

[0033] In the example illustrated in FIG. 4, the insulating film 8 covers the portion of the first electrode 51 of the piezoelectric element 5 on which the piezoelectric film 52 is not laminated, the portion of the piezoelectric film 52 on which the second electrode 53 is not laminated, and the edge of the second electrode 53. However, for example, the insulating film 8 may only cover the region of the piezoelectric element 5 on which the first lead-out wiring 9a and the second lead-out wiring 9b are disposed. Such a configuration can further decrease the rigidity of the piezoelectric element 5 while maintaining the electrical insulation property between the lead-out wirings 9a and 9b and the piezoelectric element 5, and thus the vibration efficiency can be enhanced.

[0034] Further, for example, when the first lead-out wiring 9a is connected to the first electrode 51 without the first contact 7a and led out from the end of the first electrode 51, the insulating film 8 may electrically insulate the second lead-out wiring 9b from the piezoelectric film 52 and the first electrode 51.

[0035] In the present embodiment, as illustrated in FIG. 4, the insulating film 8 is formed only around the piezoelectric element 5. Accordingly, the insulating film 8 is not formed in a region other than an arrangement region of the piezoelectric element 5 and the arrangement regions of the lead-out wirings 9a and 9b in a vibration region 103a where the diaphragm 103 is vibrated by the vibration displacement of the piezoelectric element 5. The region is referred to as an insulating film non-covered area 8b (i.e., an exposed area exposed from the insulating film 8 in an area of the vibration region 103 a outside an area of the piezoelectric element, the first wiring, and the second wiring). In addition, the protective film 11 is also formed only around the piezoelectric element 5 and the lead-out wirings 9a and 9b. A region other than the arrangement region of the piezoelectric element 5 and the arrangement regionFN202501220of the lead-out wirings 9a and 9b in the vibration region 103a is not covered with the protective film 11, which is referred to as a protective film non-covered area Ila (i.e., another exposed area exposed from the protective film 11 in an area of the vibration region 103a outside an area of the piezoelectric element, the first wiring, and the second wiring). As described above, the insulating film non-covered area 8b and the protective film non-covered area 1 la in the vibration region 103a of the diaphragm 103 can decrease the rigidity of the vibration region 103 a. As a result, the vibration region 103 a can be easily vibrated by the displacement of the piezoelectric element 5, and the vibration efficiency and the discharge efficiency of liquid droplets can be enhanced as compared with the configuration in which the entire vibration region 103 a is covered with the protective film 11 or the insulating film 8.

[0036] A region other than the vibration region 103 a of the diaphragm 103 may be covered with the protective film 11 or the insulating film 8.

[0037] A method of manufacturing the liquid discharge head 1 is described below.FIGS. 6A to 16B are diagrams illustrating a manufacturing process of the liquid discharge head 1. In FIGS. 6A to 12B and FIGS. 16A and 16B, the suffix A indicates a cross-sectional view of the liquid discharge head 1 orthogonal to an array direction of the nozzles 2, the suffix B indicates a plan view of the nozzle face in which the nozzles 2 are arrayed. FIGS. 13 to 15 are cross-sectional views of the liquid discharge head 1 orthogonal to the array direction of the nozzles 2.

[0038] First, as illustrated in FIG. 6A, the diaphragm 103 is formed on the channel substrate 100 which is a Si substrate. A complementary metal oxide semiconductor (CMOS) may be embedded in the channel substrate 100 as a drive device for driving the piezoelectric element 5. When the CMOS is embedded in the channel substrate 100, the diaphragm 103 is formed on a silicon on insulator (SOI) substrate serving as the channel substrate 100 in which a SiOi layer is sandwiched between a Si layer and a Si substrate. The CMOS is a drive circuit including a transistor and a resistor. The CMOS formed in the channel substrate 100 can reduce steps for mounting the drive circuit using another substrate and can reduce the area of an external connection portion. Accordingly, the actuator 110 can be downsized.

[0039] The CMOS and a wiring layer thereof are formed by, for example, a damascene method. Steps of depositing and patterning SiOi to form a groove, filling a wiring metal in the groove, and covering the groove with SiOi are repeated, and the surface of the formed layer is flattened by chemical mechanical polishing (CMP). Further, the above SiOi deposition and patterning are repeated to construct fine wiring having a three-dimensional structure. The wiring layer connects the CMOS and the lead-out wirings 9a and 9b led out from the piezoelectric element 5, or connects the CMOS and the electrical connection pad 6.

[0040] FN202501220As a material of the diaphragm 103 formed on the channel substrate 100, a metal oxide or nitride such as SiCh, SiN, or ZrO, a semiconductor such as SiC or GaAs, or a resin can be used. The material preferably has a low Young's modulus to increase the displacement of the diaphragm 103, and in consideration of the difference in linear expansion coefficient between the material of the diaphragm 103 and the material of the channel substrate 100, SiC having a small difference in linear expansion coefficient relative to that of the channel substrate 100 is preferable as the material of the diaphragm 103. In addition, from the viewpoint of cost, SiC is preferable as the material of the diaphragm 103.

[0041] As illustrated in FIGS. 7A and 7B, after a first electrode layer, a piezoelectric layer, and a second electrode layer are formed on the diaphragm 103, these layers are shaped into appropriate shapes to form the piezoelectric element 5 including the first electrode 51, the piezoelectric film 52, and the second electrode 53. The first electrode layer and the second electrode layer are typically formed by sputtering. For example, the piezoelectric layer is formed by sputtering or a sol-gel method. Since the sol-gel method has a high film formation temperature, there is a risk of damaging the CMOS and the wiring layer. When the CMOS and the wiring layer are embedded in the channel substrate 100, the piezoelectric layer is preferably formed by sputtering as well.

[0042] The first electrode layer, the piezoelectric layer, and the second electrode layer are processed by photolithography and etching to form the first electrode 51, the piezoelectric film 52, and the second electrode 53 each having a desired shape. Etching includes wet etching and dry etching. Dry etching can prevent corrosion of the electrodes 51 and 53 and the piezoelectric film 52. Accordingly, dry etching is preferable. After the dry etching, a residue due to the processing of the dry etching is likely to remain. For this reason, a cleaning step may be performed to remove the residue after the first electrode 51, the piezoelectric film 52, and the second electrode 53 are shaped.

[0043] The first electrode 51 and the second electrode 53 are preferably made of a metal having low electrical resistance and low reactivity, such as platinum (Pt), iridium (Ir), or molybdenum (Mo). Various materials, including PZT, are available as the piezoelectric material constituting the piezoelectric film 52. However, when the CMOS and the wiring layer are embedded in the channel substrate 100 to increase the density, a piezoelectric material having a film formation temperature of 450°C or lower is preferably used so as not to damage the CMOS and the wiring layer. Examples of the piezoelectric material having a film formation temperature of 450°C or lower include aluminum nitride (AIN).

[0044] Furthermore, the following advantages can be achieved by using AIN as the piezoelectric material. The piezoelectric property can be enhanced by aligning the crystal orientation of the piezoelectric film 52. An orientation control layer is formed between the diaphragm 103 andFN202501220the first electrode 51 to control the crystal orientation. When the piezoelectric material of the piezoelectric film 52 is AIN, AIN can be used as the orientation control layer to bring a lattice constant of the first electrode 51 made of Mo closer to that of AIN. As a result, the crystal orientation of the piezoelectric film 52 is aligned to enhance the piezoelectric property.

[0045] After the first electrode 51, the piezoelectric film 52, and the second electrode 53 are shaped, the insulating film 8 is formed as illustrated in FIGS. 8A and 8B. As with the diaphragm 103 described above, the insulating film 8 preferably has a small Young's modulus, and a linear expansion coefficient close to a linear expansion coefficient of the material of the other components. Accordingly, SiC is preferable as with the diaphragm 103. However, a very thin metal oxide film or nitride film may be formed to enhance reliability. Examples of the metal oxide include oxides of tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), and tungsten (W). Examples of the nitride include nitrides of silicon (Si), tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), and tungsten (W). Furthermore, the insulating film 8 may include the multiple oxides and nitrides described above.

[0046] After the insulating film 8 is formed, the first contact 7a and the second contact 7b, which are hole-shaped contacts, are formed in the insulating film 8 by photolithography and etching. In addition, a region of the insulating film 8 other than the region covering the piezoelectric element 5 is removed by etching to avoid an increase in Young's modulus of the diaphragm 103.

[0047] As illustrated in FIGS. 9A and 9B, the first lead-out wiring 9a and the second lead-out wiring 9b are formed. As a result of this step, the first lead-out wiring 9a is electrically connected to the first electrode 51 via the first contact 7a, and the second lead-out wiring 9b is electrically connected to the second electrode 53 via the second contact 7b. Aluminum (Al) is typically used as a material for each of the lead-out wirings 9a and 9b. Alternatively, an aluminum copper (AICu) alloy or a noble metal film, which is resistant to electromigration, may be used to enhance reliability. The first lead-out wiring 9a and the second lead-out wiring 9b are formed by dry etching, similarly to the piezoelectric element 5.

[0048] As illustrated in FIGS. 10A and 10B, a portion of the insulating film 8 covering the second electrode 53 is removed by etching, and the insulating film opening 8a is formed above the central portion of the second electrode 53. As described above, after the first lead-out wiring 9a and the second lead-out wiring 9b are formed, the portion of the insulating film 8 covering the second electrode 53 is removed to form the insulating film opening 8a. This is because, when the insulating film opening 8a is formed before the lead-out wirings 9a and 9b are formed, the second lead-out wiring 9b may be formed closer to a portion to be the nozzle 2 than the second contact 7b, and the second lead-out wiring 9b may contact the secondFN202501220electrode 53 at a position other than the second contact 7b. In such a case, it is difficult to remove the portion of the second lead-out wiring 9b contacting the second electrode 53 at the position other than the second contact 7b.

[0049] After the first lead-out wiring 9a and the second lead-out wiring 9b are formed, a portion of the insulating film 8 covering the second electrode 53 is removed to form the insulating film opening 8a. As a result, the second lead-out wiring formed closer to the portion to be the nozzle 2 than the second contact 7b can be easily removed, and the second lead-out wiring 9b can be easily formed into a desired shape.

[0050] As illustrated in FIGS. 11A and 1 IB, the protective film 11 having moisture-proof property is formed. As a material of the protective film, in addition to SiN which is common in a material of a moisture-proof film for semiconductor, a metal oxide of aluminum (Al), tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), or tungsten (W), which is easily formed in a dense film by atomic layer deposition (ALD), can be used. The protective film 11 may be a metal nitride of aluminum (Al), tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), or tungsten (W). The protective film 11 may include the multiple metal oxides and nitrides.

[0051] As illustrated in FIGS. 12A and 12B, a portion of the protective film 11 other than the portion covering the piezoelectric element 5, the portion covering the first lead-out wiring 9a, and the portion covering the second lead-out wiring 9b of the protective film 11 is removed by etching. In addition, a portion of the protective film 11 covering the terminal of the first lead-out wiring 9a (i.e., an end on one side of the liquid discharge head 1) and a portion of the protective film 11 covering the terminal of the second lead-out wiring 9b (i.e., an end on the other side of the liquid discharge head 1) are removed to form the electrical connection pads 6 at both ends of the liquid discharge head 1. As a result of the above steps, the piezoelectric element 5 can be driven.

[0052] As illustrated in FIG. 13, the nozzle forming portion 111 for forming the nozzle 2 is formed. The nozzle forming portion 111 is formed by spin coating. In other words, the nozzle forming portion (film) 111 covers (includes) the piezoelectric element 5, the first lead-out wiring 9a, the second lead-out wiring 9b, the insulating film 8, and the protective film 11. As a material for the nozzle forming portion 111, a resin that can be applied by spin coating is preferable, and from the viewpoint of chemical resistance, for example, a photoresist SU8 or benzocyclobutene (BCB) is preferable. Then, the nozzle 2 illustrated in FIG. 14 and the pad openings 10 illustrated in FIG. 15 are formed by etching. The etching of the nozzle 2 and the pad openings 10 is dry etching. Through the above steps, the nozzle vibration type actuator 110 is obtained.

[0053] FN202501220As illustrated in FIGS. 16A and 16B, the channel substrate 100 is processed by Si etching to form the multiple pressure chambers 4 each having a circular hole shape. The pressure chamber 4 is processed by a Bosch process which is a type of dry etching from the viewpoint of high controllability of dimensions and a cross-sectional shape. Then, the frame 120 in which the common liquid chamber 3 has been formed is, for example, joined to the back face of the channel substrate 100 to form the liquid discharge head 1 illustrated in FIG. 1.

[0054] As described above, the actuator is applied to the liquid discharge head of the nozzle plate vibration type. Alternatively, the actuator is also applicable to a unimorph piezoelectric head (which discharges liquid by vibrating a face opposed to the face having the nozzle of the pressure chamber).

[0055] FIG. 17 is a schematic diagram illustrating a configuration of a liquid discharge head 1A in which the actuator is applied to a unimorph piezoelectric head. As illustrated in FIG. 17, the liquid discharge head 1A includes a nozzle plate 130 in which the nozzle 2 is formed, the channel substrate 100 having the pressure chamber 4, the actuator 110, and the frame 120.

[0056] The actuator 110 includes the diaphragm 103 and the piezoelectric element 5. The diaphragm 103 is formed on a face of the channel substrate 100 opposite the face to which the nozzle plate 130 is joined. The diaphragm 103 constitutes an opposing wall facing a nozzle forming wall, on which the nozzle 2 is formed, of the pressure chamber 4.

[0057] Similarly to the above description, the insulating film 8 covers a portion of the first electrode 51 on which the piezoelectric film 52 is not laminated, a portion of the piezoelectric film 52 on which the second electrode 53 is not laminated, and an edge of the second electrode 53 of the piezoelectric element 5. Similarly to the above description, the first electrode 51 and the first lead-out wiring 9a are electrically connected via the first contact 7 a formed in the insulating film 8, and the second electrode 53 and the second lead-out wiring 9b are electrically connected via the second contact 7b formed in the insulating film 8. The first lead-out wiring 9a led out from the first electrode 51 extends to one end of the liquid discharge head 1A, and the terminal of the first lead-out wiring 9a is exposed to the outside to form the electrical connection pad 6. The second lead-out wiring 9b led out from the second electrode 53 extends to the other end of the liquid discharge head 1A, and the terminal of the second lead-out wiring 9b is exposed to the outside to form the electrical connection pad 6.

[0058] Similarly to the above description, the piezoelectric element 5, the first lead-out wiring 9a, and the second lead-out wiring 9b are entirely covered with the protective film 11 having moisture-proof property. The piezoelectric element 5 is covered with the frame 120 and protected by the frame 120. The frame 120 is joined to the protective film 11 with an adhesive.FN202501220

[0059] Also in the configuration illustrated in FIG. 17, a portion of the insulating film 8 on the central portion of the second electrode 53 of the piezoelectric element 5 is removed to form the insulating film opening 8a above the central portion of the second electrode 53.Accordingly, a part of the piezoelectric element 5 is not covered with the insulating film 8. Thus, the rigidity of the piezoelectric element 5 can be reduced and the vibration displacement of the piezoelectric element 5 can be increased as compared with the case where the insulating film 8 and the protective film 11 cover the entire piezoelectric element 5. As a result, the discharge efficiency of liquid droplets can be enhanced.

[0060] Further, the piezoelectric element 5, the first lead-out wiring 9a, and the second lead-out wiring 9b are entirely covered with the protective film 11 having moisture-proof property. Accordingly, an interface between the protective film 11 and another film is not formed in the vicinity of the piezoelectric element 5 or in the vicinity of each of the lead-out wirings 9a and 9b. Thus, corrosion of each of the lead-out wirings 9a and 9b and each of the electrodes 51 and 53 of the piezoelectric element 5 due to moisture can be reliably prevented. As a result, the actuator 110 can be stably driven for a long period of time, and a highly reliable liquid discharge head can be obtained.

[0061] Also in the present embodiment, the insulating film opening 8a is formed by removing the insulating film 8 on the central portion of the second electrode 53 of the piezoelectric element 5 after the second lead-out wiring is formed. As a result, similarly to the above description, the second lead-out wiring 9b can be easily formed into a desired shape.

[0062] Also in the present embodiment, the insulating film 8 is removed by etching except for the periphery of the piezoelectric element 5 to form a region not covered with the insulating film 8 in the vibration region 103a, which is a portion constituting the opposing wall facing the nozzle forming wall, of the diaphragm 103. As a result, the rigidity of the vibration region 103a is reduced, and the vibration region 103a can be easily vibrated by the displacement of the piezoelectric element 5. Accordingly, as compared with a configuration in which the entire vibration region 103 a is covered with the insulating film 8, the vibration efficiency and the discharge efficiency of liquid droplets can be enhanced.

[0063] The protective film 11 is also removed by etching except for the periphery of the piezoelectric element 5, the periphery of the first lead-out wiring 9a, and the periphery of the second lead-out wiring 9b to form a region not covered with the protective film 11 in the vibration region 103 a of the diaphragm 103. As a result, the rigidity of the vibration region 103 a is reduced, and the vibration region 103a can be easily vibrated by the displacement of the piezoelectric element 5. Accordingly, as compared with a configuration in which the entire vibrationFN202501220region 103a is covered with the protective film 11, the vibration efficiency and the discharge efficiency of liquid droplets can be enhanced.

[0064] A liquid discharge apparatus is described below with reference to FIGS. 18 and 19. FIG. 18 is a schematic side view of a printer 500, which is an inkjet recording apparatus as a liquid discharge apparatus. FIG. 19 is a plan view of a head unit 550 of the printer 500.

[0065] The printer 500 as the liquid discharge apparatus includes a feeder 501 and a guide conveyor 503. The feeder 501 feeds a continuous medium 510. The guide conveyor 503 guides and conveys the continuous medium 510 conveyed from the feeder 501 to a printing device 505. The printer 500 also includes the printing device 505, a dryer 507, and a carrier 509. The printing device 505 discharges liquid onto the continuous medium 510 to form an image. The dryer 507 dries the continuous medium 510. The carrier 509 ejects the continuous medium 510.

[0066] The continuous medium 510 (i.e., a medium) is fed from a winding roller 511 of the feeder 501, guided and conveyed with rollers of the feeder 501, the guide conveyor 503, the dryer 507, and the carrier 509, and wound around a take-up roller 591 of the carrier 509. In the printing device 505, the continuous medium 510 is conveyed on a conveyance guide 559 so as to face the head unit 550. The head unit 550 discharges a liquid onto the continuous medium 510 to form an image.

[0067] In the printer 500, the head unit 550 includes the two head modules 100A and 100B on a common base 552.

[0068] The head module 100A includes head arrays 1A1, 1B1, 1A2, and 1B2. Each of the head arrays 1A1, 1B1, 1A2, and 1B2 includes multiple liquid discharge heads 1 arranged in a head array direction perpendicular to a conveyance direction of the continuous medium 510. The head module 100B includes head arrays 1C1, 1D1, 1C2, and 1D2. Each of the head arrays 1C1, 1D1, 1C2, and 1D2 includes multiple liquid discharge heads 1 arranged in the head array direction. The head arrays 1A1 and 1A2 of the head module 100A discharge a liquid of the same color. Similarly, the head arrays IB 1 and 1B2 of the head module 100A are grouped as one set and discharge a liquid of the same desired color. The head arrays 1C1 and 1C2 of the head module 100B are grouped as one set and discharge a liquid of the same desired color. The head arrays 1D1 and 1D2 of the head module 100B are grouped as one set and discharge a liquid of the same desired color.

[0069] Another printer 500 as a liquid discharge apparatus is described below with reference to FIGS. 20 and 21. FIG. 20 is a plan view of a part of the printer 500. FIG. 21 is a side view of the part of the printer 500 illustrated in FIG. 20.FN202501220

[0070] The printer 500 is a serial type apparatus, and a main-scanning moving mechanism 493 reciprocally moves a carriage 403 in the main scanning direction. The main-scanning moving mechanism 493 includes a guide 401, a main scanning motor 405, and a timing belt 408. The guide 401 is bridged between left and right side plates 491 A and 49 IB to movably hold the carriage 403. The main scanning motor 405 reciprocates the carriage 403 in the main scanning direction via the timing belt 408 looped around a drive pulley 406 and a driven pulley 407.

[0071] The carriage 403 includes a liquid discharge unit 440 in which the liquid discharge head 1 and a head tank 441 are integrated into a single unit. The liquid discharge head 1 discharges color liquids of, for example, yellow (Y), cyan (C), magenta (M), and black (K). The liquid discharge head 1 is mounted on the liquid discharge unit 440 such that a nozzle row including the multiple nozzles 2 is arranged in a sub- scanning direction perpendicular to the main scanning direction. The liquid discharge head 1 discharges the color liquid downward from the multiple nozzles 2. The liquid discharge head 1 is coupled to a liquid circulation device so that a liquid of a desired color is circulated and supplied.

[0072] The printer 500 includes a conveyance mechanism 495 to convey a sheet 410 (i.e., a medium). The conveyance mechanism 495 includes a conveyance belt 412 (i.e., a conveyor) and a subscanning motor 416 to drive the conveyance belt 412. The conveyance belt 412 attracts the sheet 410 and conveys the sheet 410 to a position facing the liquid discharge head 1. The conveyance belt 412 is an endless belt looped around a conveyance roller 413 and a tension roller 414. The sheet 410 can be attracted to the conveyance belt 412 by, for example, electrostatic attraction or air suction. The conveyance belt 412 circumferentially moves in the sub-scanning direction as the conveyance roller 413 is rotationally driven by the sub-scanning motor 416 via a timing belt 417 and a timing pulley 418.

[0073] On one end of the range of movement of the carriage 403 in the main scanning direction, a maintenance mechanism 420 that maintains and recovers the liquid discharge head 1 is disposed lateral to the conveyance belt 412. The maintenance mechanism 420 includes, for example, a cap 421 to cap the nozzle face of the liquid discharge head 1 and a wiper 422 to wipe the nozzle face. The main- scanning moving mechanism 493, the maintenance mechanism 420, and the conveyance mechanism 495 are mounted onto a housing including the side plates 491 A and 49 IB and a back plate 491C.

[0074] In the printer 500 having the above-described configuration, the sheet 410 is fed and attracted onto the conveyance belt 412 and conveyed in the sub-scanning direction by the circumferential movement of the conveyance belt 412. The liquid discharge head 1 is drivenFN202501220in response to an image signal while the carriage 403 is moved in the main scanning direction to discharge a liquid onto the sheet 410 not in motion to form an image.

[0075] Another liquid discharge unit 440 is described below with reference to FIG. 22. FIG. 22 is a plan view of a part of the liquid discharge unit 440.

[0076] The liquid discharge unit 440 includes the housing, the main-scanning moving mechanism 493, the carriage 403, and the liquid discharge head 1 among components of the printer 500 as the liquid discharge apparatus illustrated in FIG. 20. The side plates 491 A and 49 IB, and the back plate 491C construct the housing.

[0077] In the liquid discharge unit 440, the maintenance mechanism 420 described above may be mounted on, for example, the side plate 49 IB.

[0078] Still another liquid discharge unit 440 is described below with reference to FIG. 23. FIG. 23 is a plan view of a part of the liquid discharge unit 440.

[0079] The liquid discharge unit 440 includes the liquid discharge head 1 to which a channel component 444 is attached, and a tube 456 connected to the channel component 444.

[0080] The channel component 444 is disposed inside a cover 442. Alternatively, the liquid discharge unit 440 may include the head tank 441 instead of the channel component 444. A connector 443 for electrically connecting to the liquid discharge head 1 is disposed on an upper portion of the channel component 444.

[0081] In the present disclosure, the liquid to be discharged is not limited to a particular liquid as long as the liquid has a viscosity or surface tension to be discharged from a head (liquid discharge head). However, preferably, the viscosity of the liquid is not greater than 30 millipascal-second (mPa- s) under ordinary temperature and ordinary pressure or by heating or cooling. Examples of the liquid include a solution, a suspension, or an emulsion that contains, for example, a solvent, such as water or an organic solvent; a colorant, such as dye or pigment; a functional material, such as a polymerizable compound, a resin, or a surfactant; a biocompatible material, such as deoxyribonucleic acid (DNA), amino acid, protein, or calcium; or an edible material, such as a natural colorant. Such a solution, a suspension, or an emulsion can be used for, e.g., inkjet ink, surface treatment solution, a liquid for forming components of electronic element or light-emitting element or a resist pattern of electronic circuit, or a material solution for three-dimensional fabrication.

[0082] Examples of an energy source for generating energy to discharge liquid include a piezoelectric actuator (a laminated piezoelectric element or a thin-film piezoelectric element),FN202501220a thermal actuator that employs a thermoelectric transducer, such as a thermal resistor, and an electrostatic actuator including a diaphragm and opposed electrodes.

[0083] The “liquid discharge unit” is an assembly of parts relating to liquid discharge. The term “liquid discharge unit” represents a structure including the liquid discharge head and a functional component(s) or mechanism(s) combined with the liquid discharge head as a single unit. For example, the “liquid discharge unit” includes a combination of the liquid discharge head with at least one of a head tank, a carriage, a supply mechanism, a maintenance mechanism, a main-scanning moving mechanism, or a liquid circulation device.

[0084] The above integration may be achieved by, for example, a combination in which the liquid discharge head and a functional component(s) or mechanism(s) are fixed to each other through, e.g., fastening, bonding, or engaging, and a combination in which one of the liquid discharge head and the functional component(s) or mechanism(s) is movably held to the other. The liquid discharge head and the functional component(s) or mechanism(s) may be detachably attached to each other.

[0085] For example, the liquid discharge head and the head tank are integrated to form the liquid discharge unit as a single unit. Alternatively, the liquid discharge head and the head tank coupled (connected) to each other via, for example, a tube may form the liquid discharge unit as a single unit. A unit including a filter may further be added to a portion between the head tank and the liquid discharge head of the liquid discharge unit.

[0086] In another example, the liquid discharge unit may be an integrated unit in which a liquid discharge head is integrated with a carriage.

[0087] As yet another example, the liquid discharge unit is a unit in which the liquid discharge head and the main-scanning moving mechanism are combined into a single unit. The liquid discharge head is movably held by a guide that is a part of the main- scanning moving mechanism. The liquid discharge unit may include the liquid discharge head, the carriage, and the main-scanning moving mechanism that are integrated as a single unit.

[0088] In another example, the cap that forms a part of the maintenance mechanism is fixed to the carriage mounting the liquid discharge head so that the liquid discharge head, the carriage, and the maintenance mechanism are integrated as a single unit to form the liquid discharge unit.

[0089] Further, in still another example, the liquid discharge unit includes tubes connected to the liquid discharge head mounting the head tank or the channel component so that the liquidFN202501220discharge head and the supply mechanism are integrated as a single unit. Through the tube, the liquid in a liquid storage source is supplied to the liquid discharge head.

[0090] The main-scanning moving mechanism may be a guide only. The supply mechanism may be a tube(s) only or a loader only.

[0091] The “liquid discharge unit” includes a head module including the above-described liquid discharge head, and a head unit with which the above-described functional components or mechanisms are combined to form a single unit.

[0092] The term “liquid discharge apparatus” used herein also represents an apparatus including the liquid discharge head, the liquid discharge unit, the head module, or the head unit to drive the liquid discharge head to discharge liquid. The liquid discharge apparatus may be, for example, any apparatus that can discharge liquid to a medium onto which liquid can adhere or any apparatus to discharge liquid toward gas or into a different liquid.

[0093] The “liquid discharge apparatus” may further include devices relating to feeding, conveying, and ejecting of the medium onto which liquid can adhere and also include a pretreatment device and an aftertreatment device.

[0094] The “liquid discharge apparatus” may be, for example, an image forming apparatus to form an image on a sheet by discharging ink, or a three-dimensional fabrication apparatus to discharge fabrication liquid to a powder layer in which powder material is formed in layers, so as to form a three-dimensional object.

[0095] The “liquid discharge apparatus” is not limited to an apparatus that discharges liquid to visualize meaningful images such as letters or figures. For example, the liquid discharge apparatus may be an apparatus that forms patterns having no meaning or an apparatus that fabricates three-dimensional images.

[0096] The above-described term “medium onto which liquid can adhere” represents a medium on which liquid is at least temporarily adhered, a medium on which liquid is adhered and fixed, or a medium into which liquid adheres and permeates. Specific examples of the “medium onto which liquid can adhere” include, but are not limited to, a recording medium such as a paper sheet, recording paper, a recording sheet of paper, a film, or cloth, an electronic component such as an electronic substrate or a piezoelectric element, and a medium such as layered powder, an organ model, or a testing cell. The “medium onto which liquid can adhere” includes any medium to which liquid adheres, unless otherwise specified.

[0097] FN202501220Examples of materials for the “medium onto which liquid can adhere” include any materials to which liquid can adhere even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramic.

[0098] The “liquid discharge apparatus” may be an apparatus to move the liquid discharge head and the medium onto which liquid can adhere relative to each other. However, the liquid discharge apparatus is not limited to such an apparatus. For example, the liquid discharge apparatus may be a serial head apparatus that moves the liquid discharge head or a line head apparatus that does not move the liquid discharge head.

[0099] Examples of the “liquid discharge apparatus” further include a treatment liquid coating apparatus to discharge a treatment liquid to a sheet to coat a surface of the sheet with the treatment liquid to reform the sheet surface. Examples of the “liquid discharge apparatus” further include an injection granulation apparatus in which a composition liquid including raw materials dispersed in a solution is injected through nozzles to granulate fine particles of the raw materials.

[0100] The terms “image formation,” “recording,” “printing,” “image printing,” and “fabricating” used herein may be used synonymously with each other.

[0101] As described above, the actuator according to an embodiment of the present disclosure is applied to the liquid discharge head. The actuator according to the above-described embodiment is also applicable to, for example, a micropump.

[0102] The embodiments described above are merely examples, and the various aspects of the present disclosure exert the respective effects as follows.Aspect 1The actuator 110 includes: the diaphragm 103 that is laminated on a substrate such as the channel substrate 100, in which a liquid chamber such as the pressure chamber 4 is formed, and constitutes a part of a wall face of the liquid chamber; the piezoelectric element 5 that includes the first electrode 51 laminated on a face of the diaphragm 103 on a side opposite a side constituting the wall face of the liquid chamber, a piezoelectric body such as the piezoelectric film 52 laminated on the first electrode 51, and the second electrode 53 laminated on the piezoelectric body; the insulating film 8 that covers the piezoelectric element and electrically insulates a wiring such as the second lead-out wiring 9b that is led out from at least the second electrode 53 from the piezoelectric body and the first electrode 51; and the protective film 11 that protects the piezoelectric element 5 from moisture. The piezoelectric element 5 has a region not covered with the insulating film 8, and the protective film 11 covers the piezoelectric element entirely.FN202501220In other words, an actuator includes a substrate, a diaphragm, and a nozzle forming film. The substrate has a liquid chamber. The diaphragm is laminated over the substrate. The diaphragm has a first face having a vibration region facing the liquid chamber and defining a part of a wall of the liquid chamber, and a second face opposite the first face. The nozzle forming film has a nozzle to discharge a liquid in the liquid chamber from the nozzle. The nozzle forming film includes a piezoelectric element, a first wiring, a second wiring, an insulating film, and a protective film. The piezoelectric element includes a first electrode over the second face of the diaphragm, a piezoelectric body over the first electrode, and a second electrode over the piezoelectric body. The first wiring is connected to the first electrode. The second wiring partially covers the piezoelectric element and is connected to the second electrode. The insulating film covers a part of the piezoelectric element to electrically insulate the second wiring from the first electrode and the piezoelectric body. The insulating film has an opening at a portion facing a central portion of the second electrode to expose the central portion from the insulating film. The protective film covers the piezoelectric element including the central portion of the second electrode exposed from the opening.According to this configuration, the vibration displacement of the piezoelectric element can be increased as compared with a case where the entire piezoelectric element is covered with the insulating film and the protective film. In addition, since the protective film covers the entire piezoelectric element, the piezoelectric element can be satisfactorily protected from moisture, and corrosion and short circuit of the piezoelectric element can be satisfactorily prevented.

[0103] Aspect 2In the actuator 110 according to Aspect 1, the insulating film 8 contains at least one of oxides of silicon (Si), tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), or tungsten (W) or nitrides of silicon (Si), tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), and tungsten (W).In other words, the insulating film includes at least one of oxides of silicon, tantalum, niobium, titanium, hafnium, zirconium, or tungsten, or nitrides of silicon, tantalum, niobium, titanium, hafnium, zirconium, or tungsten.Accordingly, the piezoelectric element 5 can be satisfactorily electrically insulated.

[0104] Aspect 3In the actuator 110 according to Aspect 1 or 2, the protective film 11 has electrical insulation property.In other words, the protective film has an electrical insulation property and a moisture-proof property.According to this configuration, the region of the piezoelectric element 5 not covered with the insulating film 8 can be electrically insulated by the protective film 11.FN202501220

[0105] Aspect 4In the actuator 110 according to Aspect 3, the protective film 11 contains at least one of a nitride of silicon (Si) or oxides of tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), or tungsten (W).In other words, the protective film includes at least one of a nitride of silicon or oxides of tantalum, niobium, titanium, hafnium, zirconium, or tungsten.According to this configuration, the piezoelectric element 5 can be satisfactorily moisture-proof, and the piezoelectric element 5 can be satisfactorily electrically insulated.

[0106] Aspect 5In the actuator 110 according to any one of Aspects 1 to 4, the protective film 11 also covers a wiring such as the first lead-out wiring 9a led out from the first electrode 51 and a wiring such as the second lead-out wiring 9b led out from the second electrode 53.In other words, the protective film further covers the first wiring and the second wiring.According to this configuration, the piezoelectric element 5 and the wirings can be protected from moisture.

[0107] Aspect 6In the actuator 110 according to any one of Aspects 1 to 5, at least the second electrode 53 has a region not covered with the insulating film 8.In other words, the piezoelectric element has an annular shape and is disposed around the nozzle. The central portion of the second electrode is in a center of the annular shape in a radial direction of the piezoelectric element.According to this configuration, since the piezoelectric element 5 is displaced in the lamination direction of the first electrode 51, the piezoelectric body, and the second electrode 53, the piezoelectric element can be satisfactorily vibrated and displaced due to the region not covered with the insulating film 8 on the second electrode 53.

[0108] Aspect 7In the actuator 110 according to Aspect 6, the insulating film 8 covers a portion of the first electrode 51 on which the piezoelectric body such as the piezoelectric film 52 is not laminated and a portion of the piezoelectric body on which the second electrode 53 is not laminated, and an end portion of the second electrode 53.In other words, the insulating film covers a portion of the first electrode on which the piezoelectric body is not laminated, a portion of the piezoelectric body on which the second electrode is not laminated, and an edge of the second electrode.According to this configuration, as described above, the wirings such as the lead-out wirings 9a and 9b led out from the piezoelectric element 5 and the piezoelectric element 5 can be satisfactorily electrically insulated.FN202501220

[0109] Aspect 8In the actuator 110 according to any one of Aspects 1 to 7, the vibration region 103 a of the diaphragm 103 constituting a part of the wall face of the liquid chamber such as the pressure chamber 4 has the insulating film non-covered area 8b that is not covered with the insulating film 8.In other words, the vibration region of the diaphragm has an exposed area exposed from the insulating film in an area of the vibration region outside an area of the piezoelectric element, the first wiring, and the second wiring.According to this configuration, as described above, the rigidity of the vibration region 103a can be reduced and the diaphragm 103 can be vibrated satisfactorily as compared with the case where the vibration region 103 a is entirely covered with the insulating film 8.

[0110] Aspect 9In the actuator 110 according to any one of Aspects 1 to 8, the vibration region 103 a of the diaphragm 103 constituting a part of the wall face of the liquid chamber such as the pressure chamber 4 has the protective film non-covered area Ila not covered with the protective film 11.In other words, the vibration region of the diaphragm has another exposed area exposed from the protective film in an area of the vibration region outside an area of the piezoelectric element, the first wiring, and the second wiring.According to this configuration, as described above, the rigidity of the vibration region 103a can be reduced and the diaphragm 103 can be vibrated satisfactorily as compared with the case where the vibration region 103 a is entirely covered with the protective film 11.

[0111] Aspect 10The liquid discharge head 1 includes the actuator according to any one of Aspects 1 to 9. The liquid discharge head 1 discharges liquid in the liquid chamber such as the pressure chamber 4 from the nozzle 2 by the actuator.In other words, a liquid discharge head includes the actuator according to any one of Aspects 1 to 9. The actuator vibrates the vibration region of the diaphragm to discharge the liquid in the liquid chamber from the nozzle.According to this configuration, as described above, the discharge efficiency of liquid droplets can be enhanced.

[0112] Aspect 11In the liquid discharge head 1 according to Aspect 10, the nozzle 2 is disposed in the actuator, and the diaphragm 103 constitutes a nozzle forming wall, in which the nozzle 2 is formed, of the liquid chamber such as the pressure chamber 4.In other words, the diaphragm defines a part of an inner wall of the nozzle.FN202501220According to this configuration, as described above, the nozzle forming wall can be vibrated to discharge liquid droplets from the nozzle 2.

[0113] Aspect 12In the liquid discharge head 1 according to Aspect 10, the diaphragm 103 constitutes an opposing wall opposed to a nozzle forming wall, in which the nozzle 2 is formed, of the liquid chamber such as the pressure chamber 4.In other words, a liquid discharge head includes the actuator according to Aspect 14. The diaphragm is opposed to the nozzle plate across the liquid chamber, and the actuator vibrates the vibration region of the diaphragm to discharge the liquid in the liquid chamber from the nozzle.According to this configuration, as described with reference to FIG. 17, the opposing wall can be vibrated to discharge liquid droplets from the nozzle 2.

[0114] Aspect 13A liquid discharge apparatus includes the liquid discharge head 1 according to any one of Aspects 10 to 12.In other words, a liquid discharge apparatus includes the liquid discharge head according to Aspect 10 or 11, to discharge the liquid onto a medium and a carriage mounting the liquid discharge head to move the liquid discharge head relative to the medium.According to this configuration, the discharge efficiency of liquid droplets can be enhanced.

[0115] Aspect 14An actuator includes a substrate, a diaphragm, a nozzle plate, a piezoelectric element, a first wiring, a second wiring, an insulating film, and a protective film. The substrate has a liquid chamber. The diaphragm is laminated over the substrate. The diaphragm has a first face having a vibration region facing the liquid chamber and defining a part of a wall of the liquid chamber, and a second face opposite the first face. The nozzle plate has a nozzle to discharge a liquid in the liquid chamber from the nozzle. The piezoelectric element includes a first electrode over the second face of the diaphragm, a piezoelectric body over the first electrode, and a second electrode over the piezoelectric body. The first wiring is connected to the first electrode. The second wiring partially covers the piezoelectric element and is connected to the second electrode. The insulating film covers the piezoelectric element to electrically insulate the second wiring from the first electrode and the piezoelectric body. The insulating film has an opening at a portion facing a central portion of the second electrode to expose the central portion from the insulating film. The protective film covers the piezoelectric element including the central portion of the second electrode exposed from the opening, the first wiring, and the second wiring.

[0116] Aspect 15FN202501220In a method of manufacturing an actuator, the actuator 110 includes: the diaphragm 103 that is laminated on a substrate such as the channel substrate 100, in which a liquid chamber such as the pressure chamber 4 is formed, and constitutes a part of a wall face of the liquid chamber; the piezoelectric element 5 that includes the first electrode 51 laminated on a face of the diaphragm 103 on a side opposite a side constituting the wall face of the liquid chamber, a piezoelectric body such as the piezoelectric film 52 laminated on the first electrode 51, and the second electrode 53 laminated on the piezoelectric body; the insulating film 8 that covers the piezoelectric element 5 and electrically insulates a wiring such as the second lead-out wiring 9b that is led out from at least the second electrode 53 from the piezoelectric body and the first electrode 51 ; and the protective film 11 that protects the piezoelectric element 5 from moisture. The method includes: forming a wiring such as the first lead-out wiring 9a led out from the first electrode 51 and a wiring such as the second lead-out wiring 9b led out from the second electrode 53 after covering the piezoelectric element 5 with the insulating film 8; removing a part of the insulating film 8 covering the piezoelectric element 5 after forming the wirings; and forming the protective film 11 after removing the insulating film 8.In other words, a method of manufacturing an actuator includes forming a liquid chamber in a substrate and laminating a diaphragm over the substrate. The diaphragm has a first face facing the liquid chamber and defining a part of a wall of the liquid chamber, and a second face opposite the first face. The method further includes laminating a first electrode of a piezoelectric element over the second face of the diaphragm, laminating a piezoelectric body of the piezoelectric element over the first electrode, laminating a second electrode of the piezoelectric element over the piezoelectric body, forming an insulating film covering the piezoelectric element, forming a first wiring to connect the first wiring to the first electrode after forming the insulating film, and forming a second wiring partially covering the piezoelectric element to connect the second wiring to the second electrode after forming the insulating film. The second wiring is electrically insulated from the first electrode and the piezoelectric body by the insulating film. The method further includes removing a part of the insulating film covering the piezoelectric element after forming the first wiring and the second wiring and forming a protective film entirely covering the piezoelectric element.According to this configuration, as described above, the wirings can be easily formed into desired shapes.

[0117] The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and / or features of different illustrative embodiments may be combined with each other and / or substituted for each other within the scope of the present invention.Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.

[0118] FN202501220The present invention can be implemented in any convenient form, for example using dedicated hardware, or a mixture of dedicated hardware and software. The present invention may be implemented as computer software implemented by one or more networked processing apparatuses. The processing apparatuses include any suitably programmed apparatuses such as a general purpose computer, a personal digital assistant, a Wireless Application Protocol (WAP) or third-generation (3G)-compliant mobile telephone, and so on. Since the present invention can be implemented as software, each and every aspect of the present invention thus encompasses computer software implementable on a programmable device. The computer software can be provided to the programmable device using any conventional carrier medium (carrier means). The carrier medium includes a transient carrier medium such as an electrical, optical, microwave, acoustic or radio frequency signal carrying the computer code. An example of such a transient medium is a Transmission Control Protocol / Intemet Protocol (TCP / IP) signal carrying computer code over an IP network, such as the Internet. The carrier medium may also include a storage medium for storing processor readable code such as a floppy disk, a hard disk, a compact disc read-only memory (CD-ROM), a magnetic tape device, or a solid state memory device.

[0119] The functionality of the elements disclosed herein may be implemented using circuitry or processing circuitry which includes general purpose processors, special purpose processors, integrated circuits, application- specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and / or combinations thereof which are configured or programmed, using one or more programs stored in one or more memories, to perform the disclosed functionality. Processors are considered processing circuitry or circuitry as they include transistors and other circuitry therein. In the disclosure, the circuitry, units, or means are hardware that carry out or are programmed to perform the recited functionality. The hardware may be any hardware disclosed herein which is programmed or configured to carry out the recited functionality.There is a memory that stores a computer program which includes computer instructions. These computer instructions provide the logic and routines that enable the hardware (e.g., processing circuitry or circuitry) to perform the method disclosed herein. This computer program can be implemented in known formats as a computer-readable storage medium, a computer program product, a memory device, a record medium such as a CD-ROM or DVD, and / or the memory of an FPGA or ASIC.

[0120] This patent application is based on and claims priority to Japanese Patent Application No. 2024-199072, filed on November 14, 2024, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.[Reference Signs List]

[0121] 1 Liquid discharge headFN2025012202 Nozzle3 Common liquid chamber4 Pressure chamber5 Piezoelectric element6 Electrical connection pad7 a First contact7b Second contact8 Insulating film8a Insulating film opening8b Insulating film non-covered area 9a First lead-out wiring9b Second lead-out wiring10 Pad opening11 Protective filmIla Protective film non-covered area 51 First electrode52 Piezoelectric body53 Second electrode100 Channel substrate103 Vibration film103 a Vibration region110 Actuator111 Nozzle forming portion120 Frame130 Nozzle plate401 Guide403 Carriage405 Main scanning motor408 Timing belt412 Conveyance belt413 Conveyance roller414 Tension roller416 Sub-scanning motor417 Timing belt420 Maintenance mechanism421 Cap422 Wiper440 Eiquid discharge unit441 Head tank444 Channel componentFN202501220456 Tube493 Main- scanning moving mechanism 495 Conveyance mechanism500 Printer501 Feeder503 Guide conveyor505 Printing device507 Dryer509 Carrier550 Head unit

Claims

FN202501220[CLAIMS]1. An actuator comprising:a substrate having a liquid chamber;a diaphragm over the substrate, the diaphragm having:a first face having a vibration region:facing the liquid chamber; anddefining a part of a wall of the liquid chamber; anda second face opposite the first face; anda nozzle forming film having a nozzle to discharge a liquid in the liquid chamber from the nozzle,wherein the nozzle forming film includes:a piezoelectric element including:a first electrode over the second face of the diaphragm;a piezoelectric body over the first electrode; anda second electrode over the piezoelectric body;a first wiring connected to the first electrode;a second wiring partially covering the piezoelectric element and connected to the second electrode;an insulating film covering a part of the piezoelectric element to electrically insulate the second wiring from the first electrode and the piezoelectric body, the insulating film having an opening at a portion facing a central portion of the second electrode to expose the central portion from the insulating film; anda protective film covering the piezoelectric element including the central portion of the second electrode exposed from the opening.

2. The actuator according to claim 1,wherein the insulating film includes at least one of:oxides of silicon, tantalum, niobium, titanium, hafnium, zirconium, or tungsten; or nitrides of silicon, tantalum, niobium, titanium, hafnium, zirconium, or tungsten.

3. The actuator according to claim 1 or 2,wherein the protective film has:an electrical insulation property; anda moisture-proof property.

4. The actuator according to claim 3,wherein the protective film includes at least one of:a nitride of silicon; oroxides of tantalum, niobium, titanium, hafnium, zirconium, or tungsten.FN2025012205. The actuator according to any one of claims 1 to 4,wherein the protective film further covers the first wiring and the second wiring.

6. The actuator according to any one of claims 1 to 5,wherein the piezoelectric element has an annular shape and is disposed around the nozzle, andthe central portion of the second electrode is in a center of the annular shape in a radial direction of the piezoelectric element.

7. The actuator according to claim 6,wherein the insulating film covers:a portion of the first electrode on which the piezoelectric body is not laminated; a portion of the piezoelectric body on which the second electrode is not laminated; andan edge of the second electrode.

8. The actuator according to any one of claims 1 to 7,wherein the vibration region of the diaphragm has an exposed area exposed from the insulating film in an area of the vibration region outside an area of the piezoelectric element, the first wiring, and the second wiring.

9. The actuator according to any one of claims 1 to 8,wherein the vibration region of the diaphragm has another exposed area exposed from the protective film in an area of the vibration region outside an area of the piezoelectric element, the first wiring, and the second wiring.

10. A liquid discharge head comprising:the actuator according to any one of claims 1 to 9,wherein the actuator vibrates the vibration region of the diaphragm to discharge the liquid in the liquid chamber from the nozzle.

11. The liquid discharge head according to claim 10,wherein the diaphragm defines a part of an inner wall of the nozzle.

12. A liquid discharge apparatus comprising:the liquid discharge head according to claim 10 or 11, to discharge the liquid onto a medium; anda carriage mounting the liquid discharge head to move the liquid discharge head relative to the medium.FN20250122013. An actuator comprising:a substrate having a liquid chamber;a diaphragm over the substrate, the diaphragm having:a first face having a vibration region:facing the liquid chamber; anddefining a part of a wall of the liquid chamber; anda second face opposite the first face;a nozzle plate having a nozzle to discharge a liquid in the liquid chamber from the nozzle;a piezoelectric element including:a first electrode over the second face of the diaphragm;a piezoelectric body over the first electrode; anda second electrode over the piezoelectric body;a first wiring connected to the first electrode;a second wiring partially covering the piezoelectric element and connected to the second electrode;an insulating film covering the piezoelectric element to electrically insulate the second wiring from the first electrode and the piezoelectric body,the insulating film having an opening at a portion facing a central portion of the second electrode to expose the central portion from the insulating film; anda protective film covering the piezoelectric element including the central portion of the second electrode exposed from the opening, the first wiring, and the second wiring.

14. A liquid discharge head comprising the actuator according to claim 13, wherein the diaphragm is opposed to the nozzle plate across the liquid chamber, and the actuator vibrates the vibration region of the diaphragm to discharge the liquid in the liquid chamber from the nozzle.

15. A method of manufacturing an actuator comprising:forming a liquid chamber in a substrate;laminating a diaphragm over the substrate, the diaphragm having:a first face:facing the liquid chamber; anddefining a part of a wall of the liquid chamber; anda second face opposite the first face;laminating a first electrode of a piezoelectric element over the second face of the diaphragm;laminating a piezoelectric body of the piezoelectric element over the first electrode; laminating a second electrode of the piezoelectric element over the piezoelectric body;FN202501220forming an insulating film covering the piezoelectric element;forming a first wiring to connect the first wiring to the first electrode after forming the insulating film;forming a second wiring partially covering the piezoelectric element to connect the second wiring to the second electrode after forming the insulating film, the second wiring electrically insulated from the first electrode and the piezoelectric body by the insulating film;removing a part of the insulating film covering the piezoelectric element after forming the first wiring and the second wiring; andforming a protective film entirely covering the piezoelectric element.

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