Actuator, droplet discharge head, unit, droplet discharge device and ultrasonic diagnostic device

Abstract

To control a substrate warpage state when a substrate having a diaphragm and a function for oscillating the diaphragm is bonded with another member.SOLUTION: An actuator 400 comprises: a diaphragm, a substrate (such as an oscillation generating substrate 500) having a diaphragm, a piezoelectric element which generates driving force, and two electrodes which make the piezoelectric element 12 generate the driving force; and a frame member 600 which adheres to the substrate to hold the substrate. On an adhesive surface which makes the substrate adhere to the frame member 600, at least one of the substrate and the frame member 600 is provided with a convex form (such as a convex form 601) which regulates a distance between the substrate and the frame member 600, wherein the convex form varies in distance as it directs to an outer periphery of the frame member 600.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an actuator, a droplet ejection head, a unit, a droplet ejection device, and an ultrasonic diagnostic device. [Background technology]

[0002] There is a technology that uses thin-film piezoelectric materials as actuators for droplet ejection heads, etc. Droplet ejection heads equipped with such actuators have the problem that the rigidity of the diaphragm that generates pressure changes due to structural warping of the actuator itself, or stress caused by warping due to differences in thermal expansion coefficients or the shrinkage stress of adhesives when bonding the actuator to another part, resulting in variations in ejection characteristics. Previously, methods such as using a reinforcing member and controlling film stress have been proposed. For example, Patent Document 1 discloses a piezoelectric device in which an adhesive is sufficiently filled between a protective substrate and a piezoelectric actuator to prevent the formation of a space and thereby prevent damage to the piezoelectric layer. However, it is not possible to avoid the effects of stress due to the difference in thermal expansion coefficient between the reinforcing material and the actuator chip, or the effects of stress due to external stress during assembly. Summary of the Invention [Problem to be solved by the invention]

[0003] An object of the present invention is to control the warpage of a substrate when a diaphragm and a substrate having a function of vibrating the diaphragm are joined to another member. [Means for solving the problem]

[0004] In order to solve the above-mentioned problems, the actuator of the present invention comprises: a substrate having a vibration plate, a piezoelectric body that generates a driving force, and two electrodes that cause the piezoelectric body to generate the driving force; a frame member that is bonded to the substrate and holds the substrate, a convex shape that defines a distance between the substrate and the frame member is provided on at least one of the substrate and the frame member at an adhesive surface that bonds the substrate and the frame member; The distance of the convex shape varies toward the outer periphery of the frame member. [Effects of the Invention]

[0005] According to the present invention, when a diaphragm and a substrate having a function of vibrating the diaphragm are joined to a separate member, the warpage of the substrate can be controlled. [Brief explanation of the drawings]

[0006] [Figure 1] 2A and 2B are schematic diagrams illustrating an example of the configuration of a droplet ejection head. [Figure 2] 10A and 10B are schematic diagrams illustrating other configuration examples of the droplet ejection head. [Figure 3] 10A and 10B are diagrams illustrating an example in which a pressure unit and the like are arranged on an actuator substrate. [Figure 4] 10A and 10B are schematic diagrams illustrating an example of a state when a vibration generating substrate and a frame member of an actuator of a comparative example are joined together. [Figure 5] 5A and 5B are schematic diagrams illustrating an example of a state when a vibration-generating substrate and a frame member of the actuator according to the embodiment of the present invention are joined together. [Figure 6] 6A and 6B are diagrams showing examples of warpage directions of a vibration-generating substrate different from those shown in FIG. 5, where (A) shows a comparative example and (B) shows an embodiment. [Figure 7] 10A and 10B are diagrams illustrating other examples of convex shapes provided on the frame member. [Figure 8] 1A and 1B are diagrams illustrating examples of tapered or rounded shapes provided on a frame member, where FIG. 1A shows an example in which a tapered shape is provided, and FIG. 1B shows an example in which a rounded shape is provided. [Figure 9] 1 is a diagram illustrating an example of the configuration of an inkjet recording apparatus equipped with a droplet ejection head according to an embodiment of the present invention. [Figure 10] FIG. 1 is a schematic diagram illustrating an example of an electrode manufacturing apparatus as a liquid ejection apparatus according to an embodiment of the present invention. [Figure 11] FIG. 1 is a schematic explanatory diagram showing an example in which an actuator according to an embodiment is applied to an ultrasonic diagnostic device. [Figure 12] FIG. 1 is a schematic diagram illustrating an example of the configuration of an ultrasonic probe. [Figure 13] FIG. 2 is a cross-sectional view showing an example of an actuator. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings for explaining the embodiments of the present invention, components such as members and components having the same function or shape are designated by the same reference numerals as far as they can be distinguished, and descriptions thereof will be omitted once they have been described.

[0008] The present invention is characterized in that, in an actuator comprising a diaphragm, a substrate (hereinafter referred to as "substrate" or "vibration-generating substrate") having the function of vibrating the diaphragm, and a separate member that holds the substrate, warping of the substrate after bonding can be suppressed by forming a convex shape on the bonding surface where the substrate and the separate member are bonded. The convex shape acts as a defining portion (defined shape) that defines the distance between the substrate and the separate member. The separate member is, for example, a frame member, and hereinafter also referred to as the "frame member" as appropriate.

[0009] In order to compensate for stress on the substrate in-plane, the actuator according to the embodiment of the present invention forms a convex shape on the surface of the substrate itself or on the surface of a frame member that is bonded to the substrate. After the convex shape is formed, the substrate and the frame member are bonded together. This allows mechanical compensation for the effect of stress due to differences in the thermal expansion coefficients between the components, making it possible to control the stress on the substrate in the in-plane direction. For example, a droplet ejection head equipped with an actuator according to the embodiment of the present invention can control variations in ejection characteristics.

[0010] Furthermore, since the warping of the substrate results in a convex or concave state in each of the longitudinal and lateral directions of the actuator, in order to correct this, it is advisable to adopt a configuration in which the distance between the substrate and the frame member (the distance between the bonding surface of the substrate and the bonding surface of the frame member) gradually decreases (the height of the convex shape decreases) or, conversely, gradually increases (the height of the convex shape increases) from the center of the substrate / frame member toward the edge in each of the longitudinal and lateral directions. This will be explained in detail using the following drawings.

[0011] 1 is a schematic diagram illustrating an example of the configuration of a droplet ejection head (also called a "liquid ejection head" or "inkjet head"), showing a cross section in the longitudinal direction of a pressurized liquid chamber. 1, the droplet ejection head 1 includes an actuator substrate 100, a support substrate 200, and a nozzle substrate 300. The droplet ejection head 1 also includes a frame member (not shown) that is bonded to the support substrate 200. The droplet ejection head 1 includes a piezoelectric body (also called a "piezoelectric body element" or "piezoelectric element") 12 that generates liquid ejection energy on the actuator substrate 100, and a vibration plate (also called a "vibration membrane") 3. The actuator substrate 100 also forms a pressurized liquid chamber partition wall 14 and a pressurized liquid chamber (also called an "individual liquid chamber") 15.

[0012] The piezoelectric element 12 is sandwiched between a common electrode (also called the "first electrode") 10 and an individual electrode (also called the "second electrode") 11, and a wiring layer (also called the "drawing wiring") 42 is laminated on each electrode layer to apply a voltage. Each pressurized liquid chamber 15 is separated by a pressurized liquid chamber partition 14. The pressurized liquid chamber 15 is formed by the actuator substrate 100 and the nozzle substrate 300. However, another substrate that forms a flow path for purposes such as rectifying the ink flow may be disposed between the actuator substrate 100 and the nozzle substrate 300. The droplet ejection head 1 is formed by bonding together the actuator substrate 100, the support substrate 200, and the nozzle substrate 300.

[0013] In the droplet ejection head 1 thus formed, with each pressurized liquid chamber 15 filled with liquid, for example, recording liquid (ink), a control unit (not shown) applies a pulse voltage of, for example, 20 V to the individual electrodes 11 corresponding to the nozzle holes 16 from which recording liquid is to be ejected, by an oscillator circuit, based on image data, via connection holes (not shown) formed in the wiring layer 42 and interlayer insulating film 45. When a voltage pulse is applied, the piezoelectric body 12 itself contracts in a direction parallel to the diaphragm 3 due to the electrostrictive effect, causing the diaphragm 3 to bend in the longitudinal direction of the pressurized liquid chamber 15.

[0014] This causes a sudden increase in pressure within the pressurized liquid chamber 15, and recording liquid is ejected from the nozzle hole 16 that communicates with the pressurized liquid chamber 15. Next, after the pulse voltage is applied, the contracted piezoelectric element 12 returns to its original state, and the deflected diaphragm 3 returns to its original position, so that the pressure within the pressurized liquid chamber 15 becomes negative compared to the pressure within the common liquid chamber (not shown), and ink that is supplied from the outside via a droplet supply port (not shown) is supplied to the pressurized liquid chamber 15. By repeating this process, droplets can be ejected continuously, and an image is formed on the recording medium (paper) placed opposite the droplet ejection head 1.

[0015] Next, an example of the operation for manufacturing the droplet ejection head 1 will be described with reference to FIG. (a) The actuator substrate 100 is a silicon single crystal substrate (for example, 400 μm thick) with a (110) surface orientation, on which the diaphragm 3 is formed. The diaphragm 3 is made by laminating silicon oxide and silicon nitride films using a method such as LP-CVD. Other materials, such as silicon or zirconium oxide, may also be used, and other elements may be implanted for stress control. Alternatively, the active layer of an SOI (Silicon on Insulator) wafer may also be used. The silicon surface orientation of the substrate is not limited to (110), and any suitable orientation for subsequent flow (processing) may be selected.

[0016] (b) Next, a common electrode 10 made of Pt and TiO2 is formed by sputtering to a thickness of 150 nm and 40 nm, respectively, and a piezoelectric layer 12 made of PZT (lead zirconate titanate) is formed in multiple layers, for example by spin coating, until a final thickness of 2 μm is achieved. Next, an upper electrode 11 made of SRO (strontium ruthenate) and Pt is formed by sputtering to a thickness of 40 nm and 100 nm, respectively. Here, the method for forming the piezoelectric layer 12 is not limited to the sol-gel method using spin coating, but may also be sputtering, ion plating, aerosol deposition, inkjet deposition, or other methods.

[0017] The upper electrode material may also be Pt, Ti, Au, Cu, etc. Here, as an example, a method for forming the piezoelectric body 12 using the sol-gel method is shown. A PZT precursor is layered on top of the Pt and then fired. The firing is carried out in three stages: drying (120°C), pre-firing (380°C), and firing (700°C). This allows the piezoelectric body 12 on the common electrode 10 to have good crystallinity with PZT (100). Then, by litho-etching, the piezoelectric bodies 12 and the individual electrodes 11 are formed at positions corresponding to the pressurized liquid chambers 15 to be formed later.

[0018] (c) Next, a wiring layer 42, for example, of TiN / Al is deposited by sputtering to a thickness of 30 nm / 3 μm, respectively. TiN is used at the connection portions with the common electrode 10 and the individual electrodes 11. The Pt material of the individual electrode 11 or common electrode 10 is directly in contact with the Al material of the wiring layer 42, and this alloy forms during thermal processing in subsequent processes. This prevents film peeling due to stress caused by volumetric changes. The wiring layer 42 may be formed using a low-resistance material, such as a material containing Au, Ni, or Cr. Furthermore, to prevent moisture penetration into the piezoelectric element, a barrier layer 50, for example, of Al2O3, is formed to a thickness of 700 nm by CVD or ALD. While the individual electrode 11 and the common electrode 10 are shown as upper and lower electrodes in FIGS. 1 and 2, these functions may be reversed. The piezoelectric element 12 may be formed so as to be connected to two different electrodes.

[0019] (d) Next, a support substrate 200 is fabricated by litho-etching, with a recess formed in a position corresponding to the actuator section 68. At this time, Si processing is performed by dry etching. Thereafter, the support substrate 200 and the actuator substrate 100 are bonded with adhesive 49 via bonding section 48. At this time, the adhesive is applied to the support substrate 200 side to a thickness of approximately 1 μm using a general thin film transfer device. Thereafter, in order to form the pressurized liquid chamber 15, the actuator substrate 100 is polished by a known technique to a desired thickness t (for example, a thickness of 80 μm). Instead of polishing, etching or other methods may also be used.

[0020] (e) Next, the liquid chamber forming layer is coated with resist by lithography. After that, anisotropic wet etching is performed using an alkaline solution (KOH solution or TMHA solution) to form the pressurized liquid chamber 15. In addition to anisotropic etching using an alkaline solution, the pressurized liquid chamber 15 may also be formed by dry etching using an ICP etcher.

[0021] (f) Next, a nozzle substrate 300 having nozzle holes 16 opened at positions corresponding to the pressurized liquid chambers 15 formed separately is bonded. (j) Next, a frame member (not shown) made of glass epoxy resin, which has a flow path for introducing ink into the actuator substrate 100, is bonded to the side of the support substrate 200 opposite to the surface bonded to the actuator substrate 100, thereby completing the droplet ejection head 1. The material for the frame member is not limited to glass epoxy resin, but if heat curing is performed during bonding, a material with a low thermal expansion coefficient relative to the silicon base material of the actuator substrate is preferable. A damper member made of PdNi or the like, or a damper frame member made of Si or the like to hold the damper member in place, may be bonded between the actuator substrate 100 and the frame member.

[0022] (h) In addition, although not explained in the above process, the ink supply port 66 is formed. Through the above-described steps, the actuator substrate 100 is formed with the vibration plate 3, the common electrode 10, the pressure applying portion made up of the piezoelectric body 12 and the individual electrode 11, the wiring layer 42, and the like.

[0023] Fig. 3 is a diagram showing a schematic arrangement of pressure units and the like provided on the actuator substrate 100. Fig. 3 shows an example of the arrangement of the actuator substrate 100 before the support substrate 200 is bonded, viewed from the surface on which the support substrate 200 is bonded. In the region 130, the members explained in FIG. 1-2, such as the diaphragm 3, the common electrode 10, the piezoelectric body 12, the individual electrodes 11, and the wiring layer 42, are provided. In the region 150, the ink supply port 66 and the like are formed. As shown in FIG. 3, a plurality of regions 130 and 150 are arranged on the actuator substrate 100. In an area 170 other than the area 130 or the area 150, a flow path or a wiring layer (not shown) is provided.

[0024] Here, the characteristics of the actuator substrate 100 manufactured by the above-described process will be described. Before being bonded to the frame member, the actuator substrate 100 has a certain amount of warping due to the internal stress of each film in the substrate and the bonding process. The presence of a warping amount indicates that stress is being applied to the actuator substrate 100, and this stress changes the rigidity of the pressure section arranged above the pressurized liquid chamber 15.

[0025] In an inkjet head, the pressure unit is vibrated and ink is ejected by inputting a voltage waveform that utilizes a resonance frequency determined by the pressure unit and the pressure chamber 15, as well as the dimensions between the pressure chamber 15 and the common chamber that supplies ink to it (not shown), the ink being used, etc. Therefore, if the rigidity of the pressure unit changes due to stress, the resonance frequency will also change, and the desired ejection characteristics will not be obtained. Furthermore, stress is generated in the actuator substrate 100 due to differences in the thermal expansion coefficient between the frame member and the actuator substrate.

[0026] Hereinafter, the features of the embodiment of the present invention will be described with reference to a comparative example, taking as an example an actuator having the above-described actuator substrate 100 and frame member. The actuator includes, for example, a vibration-generating substrate as a substrate having at least a diaphragm (diaphragm 3), a piezoelectric element (piezoelectric element 12) that generates a driving force, and two electrodes (common electrode 10 and individual electrode 11) that generate a driving force in the piezoelectric element, and a frame member that is bonded to the vibration-generating substrate and holds the vibration-generating substrate. The parentheses correspond to the configuration in Figure 1-2 described above as an example. The vibration-generating substrate may or may not include the support substrate 200 described above.

[0027] FIG. 4 is a schematic diagram showing an example of a state when the vibration generating substrate and the frame member of the actuator of the comparative example are joined together. FIG. 5 is a schematic diagram showing an example of a state when the vibration generating substrate and the frame member of the actuator according to the embodiment of the present invention are joined together. The upper parts of Figures 4 and 5 show schematic cross sections along the stacking direction when the vibration generating substrates 500P1, 500 of the actuators 400P1, 400 and the frame members 600P1, 600 are joined with adhesive 51, and the lower part of Figure 5 shows a plan view corresponding to the cross section.

[0028] As shown in FIG. 4, when a frame member 600P1 having a smooth joining surface to be joined to the vibration-generating substrate 500P1 is joined to the vibration-generating substrate 500P1, the central part of the vibration-generating substrate 500P1 warps toward the side opposite the frame member 600P1 after joining.

[0029] On the other hand, in the actuator 400 of this embodiment, in order to prevent warping of the vibration-generating substrate 500, a convex shape (also called a "convex portion") 601 is provided on the bonding surface of the frame member 600 with the vibration-generating substrate 500, as shown in Fig. 5, and the height of the convex shape 601 is gradually increased toward the outer periphery of the frame member 600. This applies pressure to the outer periphery of the vibration-generating substrate 500 in the upward direction in the figure, and as a result, it is possible to reduce warping of the vibration-generating substrate 500 after bonding. The bottom part of FIG. 5 is a view of the frame member 600 as seen from the bonding surface side with the actuator substrate 100, with the convex shape 601 colored gray and the position of the actuator substrate 100 to be bonded indicated by a dashed dotted line.

[0030] Figure 6 shows an example of the warping direction of a vibration-generating substrate different from that shown in Figure 5, where (A) shows an actuator 400P2 having a vibration-generating substrate 500P2 and a frame member 600P2 of a comparative example, and (B) shows an actuator 400A having a vibration-generating substrate 500A and a frame member 600A of an embodiment. Depending on the warping direction of the vibration-generating substrate, the convex shape 601A of the frame member 600A may be structured so that its height gradually decreases toward the periphery, as shown in FIG. 6(B).

[0031] 5 and 6(B), the convex shapes 601, 601A are discontinuous in a plane parallel to the joining surfaces of the frame members 600, 600A, but the convex shape 601B provided on the frame member 600B may be a continuous convex shape (for example, a stepped convex shape) as in the actuator 400B in Fig. 7. Furthermore, instead of a stepped structure, the convex shape 601C provided on the frame member 600C may be tapered, as in the actuators 400C, 400D in Fig. 8, or the convex shape 601D provided on the frame member 600D may be rounded. Furthermore, since the convex shape only needs to be placed between the vibration generating substrate and the frame member, it may be placed on the vibration generating substrate (e.g., the support substrate 200), or if another substrate is placed between the vibration generating substrate and the frame member, it may be placed on that other substrate.

[0032] 5-8, various examples of providing convex shapes have been described, but the present invention is not limited to these. For example, the convex shape may be a shape provided with a concave shape such as a recess. The convex shape may be provided on at least one of the vibration generating substrate 500 and the frame member 600, for example, on the bonding surface where the vibration generating substrate 500 and the frame member 600 are bonded (the bonding surface). The convex shapes may be provided at different distances toward the outer periphery of the vibration-generating substrate 500 or the frame member 600. For example, the convex shapes may be provided at different distances along at least one of a first direction (e.g., the longitudinal direction) of the actuator and a second direction (e.g., the lateral direction) intersecting the first direction.

[0033] The convex shape may be a plurality of convex portions with the distance varying stepwise, as shown in Figures 5 and 6(B), or a continuous stepped convex shape (with height varying stepwise) with the distance varying stepwise, as shown in Figure 7. The convex shape may be formed to have at least one of a tapered shape, a rounded shape, and a stepped shape, and may be, for example, a tapered or rounded shape in which the distance varies toward the periphery, as shown in Figure 8. The convex shape may be, for example, a combination of two or more of a tapered shape, a rounded shape, and a stepped shape.

[0034] The convex shape may be provided on both the vibration-generating substrate 500 and the frame member 600. For example, the convex shape of the vibration-generating substrate 500 and the convex shape of the frame member 600 may be joined by fitting together, or the surfaces of the opposing convex shapes may be used as joining surfaces, and the joining surfaces may be bonded to each other.

[0035] According to the actuator described above, by controlling warpage after bonding of the vibration plate and the substrate having the function of vibrating the vibration plate to other components, it is possible to provide, for example, an inkjet head and an inkjet recording device having excellent in-plane uniformity of ejection characteristics.

[0036] 9 shows an inkjet recording device 90 as an example of a droplet ejection device equipped with a droplet ejection head 1. This inkjet recording device 90 houses, inside the device body, a printing mechanism unit 91 composed of a carriage 98 movable in the scanning direction, the droplet ejection head 1 mounted on the carriage 98, and an ink cartridge 99 that supplies ink to the droplet ejection head 1, and has a paper feed cassette (or paper feed tray) 93 attached to the front of the device at the bottom, which can be inserted and removed from the front. The device also has a manual feed tray 94 that opens to manually feed paper 92, and takes in paper 92 fed from the paper feed cassette 93 or manual feed tray 94, records a required image on it using the printing mechanism unit 91, and then ejects the paper to a paper ejection tray 95 attached to the rear side.

[0037] The printing mechanism 91 holds a main guide rod 96 and a sub guide rod 97, which are guide members that are mounted horizontally on left and right side plates (not shown), and a carriage 98 so that they can slide in the main scanning direction, and this carriage 98 is equipped with a droplet ejection head 1 that ejects ink droplets of each color (yellow (Y), cyan (C), magenta (M), and black (Bk)) with multiple ink ejection ports (nozzles) arranged in a direction intersecting the main scanning direction and with the ink droplet ejection direction facing downward. Also, each ink cartridge 99 for supplying ink of each color to the droplet ejection head 1 is replaceably mounted on the carriage 98.

[0038] The ink cartridge 99 has an air port at the top that communicates with the atmosphere, a supply port at the bottom that supplies ink to the droplet ejection head 1, and a porous body filled with ink inside, and the ink supplied to the droplet ejection head 1 is maintained at a slight negative pressure by the capillary force of the porous body. Also, droplet ejection heads 1 for each color are used as the droplet ejection head 1, but a single droplet ejection head having nozzles that eject ink droplets of each color may also be used.

[0039] Here, the rear side (downstream side of paper transport) of the carriage 98 is slidably fitted onto a main guide rod 96, and the front side (upstream side of paper transport) is slidably mounted on a slave guide rod 97. In order to move the carriage 98 in the main scanning direction, a timing belt 104 is stretched between a drive pulley 102 and a driven pulley 103, which are driven to rotate by a main scanning motor 101, and the timing belt 104 is fixed to the carriage 98, so that the carriage 98 is driven to reciprocate by the forward and reverse rotation of the main scanning motor 101.

[0040] On the other hand, in order to transport the paper 92 set in the paper feed cassette 93 downward toward the droplet ejection head 1, there are provided a paper feed roller 105 and a friction pad 106 that separate and feed the paper 92 from the paper feed cassette 93, a guide member 107 that guides the paper 92, a transport roller 108 that inverts and transports the fed paper 92, a transport roller 109 that is pressed against the circumferential surface of the transport roller 108, and a tip roller 110 that determines the feed angle of the paper 92 from the transport roller 108. The transport roller 108 is rotated by a sub-scanning motor via a gear train.

[0041] An image receiving member 111, which is a paper guide member, is provided to guide the paper 92 sent out from the transport roller 108 below the droplet ejection head 1 in accordance with the range of movement of the carriage 98 in the main scanning direction. On the downstream side of the image receiving member 111 in the paper transport direction, there are provided a transport roller 112 and a spur 113 that are driven to rotate to send out the paper 92 in the paper discharge direction, and further provided are a paper discharge roller 114 and a spur 115 that send out the paper 92 to the paper discharge tray 95, and guide members 116 and 117 that form a paper discharge path.

[0042] During recording with this inkjet recording device 90, the carriage 98 is moved while the droplet ejection head 1 is driven in response to an image signal, thereby ejecting ink onto the stationary paper 92 to record one line, and then the paper 92 is transported a predetermined distance before recording the next line. Upon receiving a recording end signal or a signal indicating that the rear end of the paper 92 has reached the recording area, the recording operation is terminated and the paper 92 is ejected.

[0043] Furthermore, a recovery device 117 for recovering from ejection defects of the droplet ejection head 1000 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 98. The recovery device 117 has capping means, suction means, and cleaning means. When the carriage 98 is on standby for printing, it moves to the side of this recovery device 117 and caps the droplet ejection head 1 with the capping means, keeping the ejection ports moist and preventing ejection defects due to dried ink. Furthermore, by ejecting ink unrelated to recording during recording, the viscosity of the ink at all ejection ports is kept constant and a stable ejection state is maintained.

[0044] In addition, if a discharge failure occurs, the discharge outlet (nozzle) of the droplet discharge head 1 is sealed with a capping means, and air bubbles along with the ink are sucked out of the discharge outlet through a tube with a suction means, and ink and dust adhering to the discharge outlet surface are removed by a cleaning means, thereby recovering from the discharge failure. The sucked ink is also discharged into a waste ink reservoir (not shown) installed at the bottom of the main body, and is absorbed and held in an ink absorber inside the waste ink reservoir.

[0045] In this way, since the inkjet recording apparatus 90 is equipped with the droplet ejection head 1 manufactured according to the present invention, stable ink ejection characteristics are obtained, and image quality is improved. In the above explanation, the droplet ejection head 1 is used in the inkjet recording device 90, but the droplet ejection head 1 may also be applied to a device that ejects droplets other than ink, for example, a liquid resist for patterning.

[0046] In the following, application examples will be described in which the actuator according to the embodiment of the present invention described above or a droplet ejection device (also called a "liquid ejection device") including the actuator is applied.

[0047] Application example 1. <Electrode manufacturing equipment> The "liquid ejecting device" according to the embodiment of the present invention also includes a manufacturing device for an electrode and an electrochemical element. An electrode manufacturing device will be described below.

[0048] 10 is a schematic diagram showing an example of an electrode manufacturing apparatus as a liquid ejection apparatus according to an embodiment of the present invention in Application Example 1. The electrode manufacturing apparatus is an apparatus that manufactures an electrode including a layer having an electrode material by ejecting a liquid composition using a head module including a liquid ejection head.

[0049] <Means for forming layer containing electrode material, and process for forming layer containing electrode material> The discharge means provided in the electrode manufacturing apparatus shown in FIG. 10 is a head module according to the embodiment of the present invention. A liquid composition is applied to a target object by being discharged from a discharge head included in the head module, thereby forming a liquid composition layer. The target object (hereinafter also referred to as a "discharge target") is not particularly limited as long as it is an object on which a layer containing an electrode material is to be formed, and can be appropriately selected depending on the purpose. For example, the target object may be an electrode substrate (current collector), an active material layer, a layer containing a solid electrode material, or the like. The target object may also be an electrode mixture layer containing an active material on an electrode substrate (current collector). The discharge means and discharge step may also be a means and step for directly discharging a liquid composition to form a layer containing an electrode material, as long as it is possible to form a layer containing an electrode material on the discharge target object. The discharge means and discharge step may also be a means and step for indirectly discharging a liquid composition to form a layer containing an electrode material.

[0050] <Other components and processes> Other components included in the manufacturing apparatus for an electrode mixture layer are not particularly limited as long as they do not impair the effects of the present invention, and can be selected appropriately depending on the purpose. Furthermore, other steps included in the manufacturing method for an electrode mixture layer are also not particularly limited as long as they do not impair the effects of the present invention, and can be selected appropriately depending on the purpose. For example, components and steps included in the manufacturing apparatus and manufacturing method for an electrode mixture layer include a heating means and a heating step.

[0051] <Heating means, heating process> The heating means included in the manufacturing device for the electrode mixture layer is a means for heating the liquid composition ejected by the ejection means. Also, the heating step included in the manufacturing method for the electrode mixture layer is a step of heating the liquid composition ejected in the ejection step. By heating the liquid composition, the liquid composition layer can be dried.

[0052] <Configuration for forming a layer containing an electrode material by directly ejecting a liquid composition> Here, as an example of an electrode manufacturing apparatus, an electrode manufacturing apparatus that forms an electrode mixture layer containing an active material on an electrode substrate (current collector) will be described. As shown in Fig. 10, the electrode manufacturing apparatus includes a discharge process unit 110 that includes a step of applying a liquid composition to a printing substrate 704 having an object to be discharged to form a liquid composition layer, and a heating process unit 120 that includes a heating step of heating the liquid composition layer to obtain an electrode mixture layer.

[0053] The electrode manufacturing apparatus includes a conveying unit 705 that conveys a printing substrate 704. The conveying unit 705 conveys the printing substrate 704 at a preset speed through the discharging process unit 110 and the heating process unit 120 in that order. There are no particular limitations on the method for manufacturing the printing substrate 704 having a discharge target such as an active material layer, and any known method can be appropriately selected. The discharging process unit 110 includes a liquid discharge head 281a that performs the application step of applying a liquid composition onto the printing substrate 704, a storage container 281b that stores the liquid composition 707, and a supply tube 281c that supplies the liquid composition 707 stored in the storage container 281b to the liquid discharge head 281a.

[0054] In the discharge process unit 110, the liquid composition 707 is discharged from the liquid discharge head 281a and applied to the printing substrate 704, thereby forming a thin film of the liquid composition layer. The storage container 281b may be configured as an integral part of the manufacturing apparatus for the electrode mixture layer, or may be configured as a removable part from the manufacturing apparatus for the electrode mixture layer. The storage container 281b may be a container used for adding the liquid to a storage container that is integrated with the manufacturing apparatus for the electrode mixture layer, or a storage container that is removable from the manufacturing apparatus for the electrode mixture layer.

[0055] The storage container 281b and the supply tube 281c can be arbitrarily selected as long as they can stably store and supply the liquid composition 707.

[0056] In the heating process section 120, a solvent removal step is carried out in which the solvent remaining in the liquid composition layer is heated and removed. Specifically, the solvent remaining in the liquid composition layer is heated and dried by the heating device 706 in the heating process section 120, thereby removing the solvent from the liquid composition layer. This results in the formation of an electrode mixture layer. The solvent removal step in the heating process section 120 may also be carried out under reduced pressure.

[0057] The heating device 706 is not particularly limited and can be appropriately selected depending on the purpose. For example, the heating device 706 can be a substrate heater, an IR heater, a hot air heater, or the like. The heating device 706 may also be a combination of at least two of the substrate heater, the IR heater, and the hot air heater. The heating temperature and heating time can be appropriately selected depending on the boiling point of the solvent contained in the liquid composition 707 or the thickness of the formed film.

[0058] By using the electrode manufacturing apparatus according to an embodiment of the present invention, a liquid composition can be ejected onto a target object. The electrode mixture layer can be suitably used, for example, as part of the configuration of an electrochemical element. The components other than the electrode mixture layer in the electrochemical element are not particularly limited, and known components can be appropriately selected. For example, components other than the electrode mixture layer include a positive electrode, a negative electrode, a separator, and the like.

[0059] Application example 2. <Ultrasound diagnostic equipment> Next, other application examples of the actuator will be described. The actuator according to the embodiment is not limited to ejecting liquid, and may be used, for example, to emit ultrasonic waves. Below, an example in which the actuator according to the embodiment is applied to an ultrasonic diagnostic device will be described.

[0060] FIG. 11 is a schematic explanatory diagram showing an example in which the actuator according to the embodiment is applied to an ultrasonic diagnostic apparatus. The ultrasonic diagnostic device 700 includes an ultrasonic probe 750 that emits ultrasonic waves toward a measurement object U and detects vibrations of the ultrasonic waves reflected by the measurement object U. The ultrasonic diagnostic device 700 also includes a display unit 701 that visualizes and displays a signal from the ultrasonic probe 750, an operation unit 702, and a control unit 703 that controls the ultrasonic probe 750.

[0061] The control unit 703 generally includes an ultrasonic pulse generating unit that generates a pulsed electrical signal to generate an ultrasonic signal, a converting unit that converts the echo signal received from the ultrasonic probe 750 into an electrical signal, and an ultrasonic image forming unit that forms a two-dimensional ultrasonic image, a three-dimensional ultrasonic image, or various Doppler images from the echo signal.

[0062] The display unit 701 is an LCD (Liquid Crystal Display) or a monitor device, and displays an image formed by the control unit 703. The operation unit 702 is an input means for inputting parameters etc. so that the operator can perform an appropriate diagnosis of the measurement object U, and may use a push button, a touch panel, etc.

[0063] The ultrasonic probe 750 is electrically connected to the control unit 703 via a cable or the like, transmits ultrasonic signals toward a measurement object U, which may be a human body or an object, and receives ultrasonic signals reflected as echoes from the measurement object U. In this way, the ultrasonic diagnostic device 700 can visualize and diagnose the inside of the measurement object U by transmitting and receiving ultrasonic signals.

[0064] FIG. 12 is a schematic diagram showing an example of the configuration of an ultrasonic probe. The ultrasonic probe 750 includes a support portion 751 which is a support substrate, a PMUT (Piezoelectric Micro-Machined Ultrasonic Transducer) chip 752 which is an ultrasonic transducer formed on the support portion 751, a flexible substrate 753, wiring 754, connectors 755 and 756, and an acoustic lens 757. The PMUT chip 752 is electrically connected to the connectors 755 and 756 via the flexible substrate 753 and wiring 754, and is connected to the control unit 703 from the connectors 755 and 756 via a circuit board.

[0065] The support portion 751 also functions as a backing plate for holding the PMUT chip 752 .

[0066] Acoustic lens 757 is an acoustic lens made of silicone resin that focuses ultrasonic waves emitted from PMUT chip 752 onto the measurement position of measurement object U. Acoustic lens 757 has a so-called dome shape with the center being thicker than the periphery, and by abutting and closely contacting measurement object U, the difference in thickness between the center and periphery provides the function of artificially refracting and focusing ultrasonic waves. Note that acoustic lens 757 only needs to have the function of focusing ultrasonic waves in at least one direction, and does not necessarily have to focus ultrasonic waves onto a single point. Acoustic lens 757 and PMUT chip 752 are bonded together, for example, with an adhesive.

[0067] The PMUT chip 752 includes a plurality of actuators 800 arranged in an array. The actuators 800 will be described in detail below. FIG. 13 is a cross-sectional view showing an example of an actuator.

[0068] Actuator 800 includes silicon substrate 810, wiring section 820, vibrating membrane 830, piezoelectric element 850, insulating film 860, lead wiring 870, and protective film (moisture-proof film) 880. Silicon substrate 810 has formed therein gap section 840 formed of, for example, a cylindrical opening, and wiring section 820 is laminated on silicon substrate 810.

[0069] Wiring section 820 is formed on silicon substrate 810, and includes a wiring section for applying a bias to first electrode 851, and a wiring section for applying a bias to second electrode 853. Vibration membrane 830 serving as a diaphragm member is laminated on wiring section 820.

[0070] 13 by receiving vibrations from piezoelectric element 850. Piezoelectric element 850 provided on vibrating membrane 830 includes first electrode (also referred to as lower electrode) 851, piezoelectric body 852, and second electrode (also referred to as upper electrode) 853.

[0071] The first electrode 851 has a width (outer diameter) L1, which is smaller than the width (inner diameter) L4 of the void portion 840 formed in the silicon substrate 810, and is provided with an outer shape that allows the first electrode 851 to fit inside the void portion 840.

[0072] Second electrode 853 is formed along the upper surface side of dome-shaped piezoelectric body 852. The outer diameter (L3) of second electrode 853 is desirably smaller than the outer diameter (L2) of piezoelectric body 852, and particularly when piezoelectric body 852 is a dome-shaped piezoelectric body, making the outer diameter of second electrode 853 smaller than the outer shape of piezoelectric body 852 can prevent short-circuiting between second electrode 853 and first electrode 851.

[0073] The insulating film 860 prevents a short circuit between the first electrode 851 and the second electrode 853, and a short circuit between the lead wiring 870 and the first electrode 851. In the embodiment, the piezoelectric body 852 has a dome shape, but this is not limited to this. The shape of the piezoelectric body 852 may be a shape other than a dome shape, such as a cylindrical shape.

[0074] In the above configuration, when a drive voltage is applied between the first electrode 851 and the second electrode 853, the piezoelectric body 852 undergoes mechanical deformation, and the periodic fluctuation of the drive voltage causes vibrations of a predetermined frequency, which vibrates the vibrating membrane 830 and generates ultrasonic waves W.

[0075] Furthermore, when ultrasonic waves vibrate the piezoelectric body 852, the piezoelectric body 852 is polarized, generating a potential difference between the first electrode 851 and the second electrode 853, and the actuator 800 also functions as a detection means for detecting the vibration as an electric signal. In this way, the actuator 800 functions as an electromechanical conversion element that periodically expands and contracts the piezoelectric body 852 by the potential difference between the first electrode 851 and the second electrode 853, i.e., the electric signal, thereby generating vibration. In this embodiment, in particular, the actuator 800 functions as an ultrasonic transducer that generates sound waves in the ultrasonic range by vibration.

[0076] Even in actuator 800 configured as described above, by setting the outer shape of first electrode 851 to a shape that fits inside gap 840, fixed ends P1 and P2 of vibrating membrane 830 can be made to move easily, and vibrating membrane 830 can be favorably vibrated. Furthermore, the deformation efficiency of vibrating membrane 830 in response to voltage increases, and a decrease in responsiveness to high frequencies can be suppressed.

[0077] In the present invention, a "liquid ejecting device" is a device that includes a liquid ejection head or a liquid ejection unit (also referred to as a "unit") and ejects liquid by driving the liquid ejection head. Liquid ejecting devices include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0078] This "liquid ejecting device" can also include means for supplying, transporting, and discharging objects onto which the liquid can be attached, as well as other pre-processing devices, post-processing devices, etc. For example, "liquid ejecting devices" include an image forming device that ejects ink to form an image on paper, and a three-dimensional modeling device (three-dimensional modeling device) that ejects modeling liquid onto a powder layer formed by layering powder in order to form a three-dimensional object (a three-dimensional model).

[0079] Furthermore, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves, and devices that create three-dimensional images.

[0080] The above-mentioned "object onto which a liquid can adhere" means an object onto which a liquid can adhere at least temporarily, an object onto which the liquid can adhere and stick, an object onto which the liquid can penetrate, etc. Specific examples include media such as paper, recording paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects onto which a liquid can adhere.

[0081] The material of the "object to which a liquid can adhere" may be any material to which a liquid can adhere, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, textiles for clothing, current collectors such as aluminum foil or copper foil, or electrodes with an active material layer formed on a current collector.

[0082] The "liquid" may be any liquid having a viscosity and surface tension that allows it to be ejected from a head, but is not particularly limited thereto. Preferably, the viscosity of the liquid is 30 mPa·s or less at room temperature and pressure, or upon heating or cooling. More specifically, examples of such liquids include solutions, suspensions, and emulsions containing solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, surfactants, and other functionalizing materials, biocompatible materials such as DNA, amino acids, proteins, and calcium, edible materials such as natural dyes, active materials used as electrode materials, solid electrolytes, and inks containing conductive and insulating materials. These liquids can be used, for example, in inkjet inks, surface treatment solutions, liquids for forming components of electronic devices and light-emitting elements, and electronic circuit resist patterns, 3D modeling materials, electrodes, electrochemical devices, and the like. "Liquid" also includes ink, processing liquid, DNA sample, resist, pattern material, binder, modeling liquid, or solutions and dispersions containing amino acids, proteins, calcium, and the like.

[0083] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object onto which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, and a line type device in which a liquid ejection head does not move.

[0084] Other examples of "liquid ejecting devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0085] Furthermore, the "liquid ejecting device" is not limited to a stationary device. The liquid ejecting device may be, for example, a robot equipped with a liquid ejection head and capable of moving by remote control or autonomous driving, and a mobile robot may be used to paint the exterior walls of buildings or road markings (crosswalks, stop lines, speed signs, etc.). In this case, buildings and roads are also included in the "objects to which liquid can adhere."

[0086] A "liquid ejection unit" is a collection of components related to the ejection of liquid, integrating functional parts and mechanisms with a liquid ejection head. For example, a "liquid ejection unit" includes a combination of a liquid ejection head and at least one of the following components: a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, and a main scanning movement mechanism.

[0087] Here, "integrated" includes, for example, a liquid ejection head and a functional part or mechanism that are fixed to each other by fastening, bonding, engaging, etc., or one that is held movably relative to the other. The liquid ejection head, functional part, or mechanism may also be configured to be detachable from each other.

[0088] Furthermore, the pressure generating means used in the "liquid ejection head" is not limited. For example, in addition to the piezoelectric actuator (which may use a laminated piezoelectric element) as described in the above embodiment, a thermal actuator using an electrothermal conversion element such as a heating resistor, or an electrostatic actuator consisting of a vibration plate and an opposing electrode may also be used.

[0089] In addition, in the present application, the terms image formation, recording, printing, copying, printing, modeling, etc. are all synonymous.

[0090] For example, aspects of the present invention are as follows. <1> a substrate having a vibration plate, a piezoelectric body that generates a driving force, and two electrodes (for example, a first electrode and a second electrode) that cause the piezoelectric body to generate the driving force; a frame member that is bonded to the substrate and holds the substrate, a convex shape that defines a distance between the substrate and the frame member is provided on at least one of the substrate and the frame member at an adhesive surface that bonds the substrate and the frame member; The actuator is characterized in that the distance of the convex shape varies toward the outer periphery of the frame member. <2> The convex shape is formed so that the distance varies along at least one of a first direction and a second direction (for example, a longitudinal direction or a lateral direction) of the actuator that intersects with the first direction. The above-mentioned <1> 2. The actuator according to claim 1 . <3> The convex shape is a plurality of convex portions whose distances differ stepwise. The above-mentioned <1> or <2> 2. The actuator according to claim 1 . <4> The convex shape has at least one of a tapered shape, a rounded shape, and a stepped shape. The above-mentioned <1> or <2> 2. The actuator according to claim 1 . <5> the convex shape is provided on the substrate and the frame member, The convex shape of the substrate and the convex shape of the frame member are bonded either by fitting the convex shape of the substrate and the convex shape of the frame member together, or by using the opposing surfaces of the convex shape of the substrate and the convex shape of the frame member as bonding surfaces. The above-mentioned <1> from <4> The actuator is any one of the above. <6> The aforementioned <1> from <5> an actuator according to any one of the above items; a nozzle for ejecting droplets, The actuator further includes a pressure chamber for generating pressure. The droplet ejection head is characterized by the above features. <7> The aforementioned <6> 10. A unit including the droplet ejection head according to claim 19. <8> The aforementioned <7> A droplet ejection device comprising the unit according to claim 1. <9> The aforementioned <1> from <5> 10. An ultrasonic diagnostic apparatus including the actuator according to claim 19.

[0091] The present invention is not limited to the above-described embodiments. Within the scope of the present invention, the elements of the above-described embodiments can be modified, added, or converted into content that would be easily conceivable by a person skilled in the art. Furthermore, two or more of the above-described embodiments can be combined as appropriate. [Explanation of symbols]

[0092] 1. Droplet ejection head (liquid ejection head) 3 Vibration plate 10 common electrode 11 individual electrodes 12 Piezoelectric 14 Pressurized liquid chamber partition 15 Pressurized fluid chamber 42 Wiring layer 49 Adhesive (adhesive that bonds the actuator substrate and the support substrate) 51 Adhesive (adhesive that joins frame members and vibration generating substrate) 100 Actuator board 200 Support substrate 300 nozzle board 400, 400A~400D Actuator 500, 500A-500D Vibration generating board (board) 600, 600A-600D frame members 601, 601A~601D Convex shape [Prior art documents] [Patent documents]

[0093] [Patent Document 1] Japanese Patent Application Publication No. 2023-115537

Claims

1. a substrate having a vibration plate, a piezoelectric body that generates a driving force, and two electrodes that cause the piezoelectric body to generate the driving force; a frame member that is bonded to the substrate and holds the substrate, a convex shape that defines a distance between the substrate and the frame member is provided on at least one of the substrate and the frame member at an adhesive surface that bonds the substrate and the frame member; The actuator is characterized in that the distance of the convex shape varies toward the outer periphery of the frame member.

2. The convex shape is formed such that the distance varies along at least one of a first direction and a second direction intersecting the first direction of the actuator.

2. The actuator according to claim 1.

3. The convex shape is a plurality of convex portions whose distances differ stepwise.

3. The actuator according to claim 1 or 2.

4. The convex shape has at least one of a tapered shape, a rounded shape, and a stepped shape.

3. The actuator according to claim 1 or 2.

5. the convex shape is provided on the substrate and the frame member, The convex shape of the substrate and the convex shape of the frame member are bonded either by fitting the convex shape of the substrate and the convex shape of the frame member together, or by using the opposing surfaces of the convex shape of the substrate and the convex shape of the frame member as bonding surfaces.

3. The actuator according to claim 1 or 2.

6. The actuator according to claim 1 or 2; a nozzle for ejecting droplets, The actuator further includes a pressure chamber for generating pressure. A droplet ejection head characterized by:

7. A unit comprising the droplet ejection head according to claim 6.

8. A droplet ejection device comprising the unit according to claim 7.

9. An ultrasonic diagnostic apparatus comprising the actuator according to claim 1 or 2.

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