JP4617765B2 - FUNCTIONAL ELEMENT AND ITS MANUFACTURING METHOD, FLUID DISCHARGE DEVICE, AND PRINTING DEVICE - Google Patents

Description

  The present invention relates to a functional element having a function as a vibration actuator, a manufacturing method thereof, and a fluid ejection device and a printing apparatus configured using the functional element.

  In recent years, functional elements having a function as a vibration actuator formed by a thin film forming technique are being used. The “thin film formation technique” refers to a technique for forming a thin film by performing vapor deposition, sputtering, etching, or the like, for example, as used when performing fine processing on a silicon semiconductor substrate in a semiconductor manufacturing process. The “functional element having a function as a vibration actuator” refers to an element configured to include a vibrator that exhibits some response to an input signal. As an example of such a functional element, so-called MEMS (Micro Electro Mechanical Systems) is known.

  Here, as a specific example in which a functional element having a function as a vibration actuator is used, an inkjet head (fluid ejection device) constituting a printing apparatus such as a printer or a facsimile is taken as an example, and the configuration will be briefly described. . The ink jet head includes a nozzle that discharges ink liquid, a flow path (pressure chamber) of ink liquid that communicates with the nozzle, and a vibration actuator that pressurizes the ink liquid in the flow path, and drives the vibration actuator. The ink liquid is pressurized and the ink is ejected from the nozzles. Conventionally, it has been proposed to use a functional element that vibrates a vibrator (diaphragm) using an electrostatic force (Coulomb force) as a vibration actuator constituting the ink jet head (see, for example, Patent Document 1). Specifically, a part of the flow path of the ink liquid is formed by a vibrationally supported vibration plate, and an electric field is applied to the electrode pair provided along with the vibration plate, so that the gap between the electrode pairs is formed. Then, an electrostatic force is generated to deform the diaphragm, thereby changing the pressure and volume in the liquid chamber, thereby ejecting the ink liquid from the nozzle.

  The functional element used in such an ink jet head needs to be formed with a thin diaphragm. This is because the thickness of the thick diaphragm is likely to vary, and as a result, the printing quality and reliability may be reduced. However, when the diaphragm is thin, the rigidity is insufficient and sufficient repulsive force cannot be secured, and there is a possibility that sufficient ejection force sufficient for ejecting ink liquid cannot be obtained. For this reason, with respect to a functional element that functions as a vibration actuator, it has been proposed to support the diaphragm with a plurality of support columns in order to impart sufficient rigidity to the thin diaphragm (see, for example, Patent Document 2). .

Japanese Patent No. 2854876 JP 7-246706 A

  By the way, in order to meet the demands for higher print image quality and higher print output speed for inkjet heads, nozzles can be installed without increasing power consumption and reducing ink discharge performance. It is required to arrange them at high density.

  However, an inkjet head configured using the above-described functional elements, that is, an inkjet head using an electrostatic method, consumes less power and has a higher driving frequency than other types such as a resistance heating method. Although features can be obtained, a nozzle having a nozzle density of about 180 npi is common to a resistance heating method that reaches a nozzle density of about 800 npi (nozzle per inch). About this nozzle density, even if it is an electrostatic system, it is realizable to about 300 npi by arrange | positioning a nozzle by the pinching pitch in a line. However, in an ink jet head using an electrostatic method, if the nozzles are arranged at a narrow pitch, the flow path (pressure chamber) of the ink liquid becomes narrow accordingly, and thus the flow path resistance increases. As a result, the ink liquid is discharged. There is a possibility that efficiency will deteriorate.

  For this reason, in the inkjet head using the electrostatic system, the arrangement structure of the nozzles and vibration actuators has been reviewed, and the vibration actuators with the diaphragms arranged in a line like in the case where the nozzles are arranged in a row, and the pitch between the nozzles is reduced. Instead of realizing the above, by arranging vibration actuators with vibration plates formed in a circular shape or a square shape regularly, the in-plane density on the printed image is increased instead of the density on the row. It is conceivable to meet the demand for higher density nozzle arrangement.

  However, in order to obtain the required discharge volume and discharge speed, a displacement volume corresponding to the discharge volume must be secured. Therefore, if the vibration plate of the vibration actuator is made circular or square, the displacement volume and repulsion of the vibration plate are reduced. Power is a problem. It is the short side length that mainly defines the repulsive force of the diaphragm. However, if the diaphragm is made circular or rectangular, the diameter (short side length) naturally becomes large. Therefore, there is a possibility that a sufficient repelling force sufficient for discharging the ink liquid cannot be obtained. With respect to this point, as disclosed in the above-mentioned Patent Document 2, it is conceivable that the diaphragm is supported by a plurality of support columns to ensure a sufficient repulsive force. Even if the rigidity can be ensured, it is not always possible to vibrate the diaphragm efficiently. That is, the vibration actuator cannot always be operated efficiently. Therefore, for example, there is a possibility that desired characteristics cannot be obtained in terms of power consumption, ejection force, and the like.

  Therefore, the present invention can easily cope with a high-density arrangement and can obtain an efficient fluid discharge characteristic even in a high-density arrangement, a manufacturing method thereof, a fluid discharge apparatus, and printing. An object is to provide an apparatus.

The present invention is a functional device devised to achieve the above object.
That is, a plurality of diaphragms, a plurality of support portions that are arranged in an annular shape with respect to the plurality of diaphragms, and each of the diaphragms is deformably supported, and the diaphragm is deformed by an electrostatic force to form a fluid. An electrode pair composed of two electrodes that give a pressure change, and at least one of the two electrodes is divided into a plurality of individual electrodes, and each individual electrode of the electrode pair can be driven independently, and driving of the individual electrodes to be driven by varying the timing, that each of the plurality of individual electrodes have a and matching possible drive means at a specific location each phase of the change in pressure applied to the fluid.

The present invention is also a functional device manufacturing method devised to achieve the above object.
That is, a plurality of diaphragms, a plurality of support portions that are arranged in an annular shape with respect to the plurality of diaphragms, and each of the diaphragms is deformably supported, and the diaphragm is deformed by an electrostatic force into a fluid. An electrode pair composed of two electrodes that give a pressure change, and at least one of the two electrodes is divided into a plurality of individual electrodes, and each individual electrode of the electrode pair can be driven independently, and driving of the individual electrodes to be driven by varying the timing, when each of the plurality of individual electrodes forming the plurality of supporting portions of the functional elements that have a and matching possible drive means at a specific location each phase of the change in pressure applied to the fluid, each support portion that HSS so that annular.

The present invention is also a devised fluid ejection device for achieving the above object.
That is, a pressure chamber having a nozzle capable of projecting a fluid in a room, a plurality of diaphragms, a plurality of support portions that are arranged in an annular shape and support each diaphragm in a deformable manner, and the diaphragm It consists of two electrodes that are deformed by an electrostatic force to change the pressure of the fluid. At least one of the two electrodes is divided into a plurality of individual electrodes, and each individual electrode of the electrode pair can be driven independently , and the by changing the drive timing of the individual electrodes to be driven, that having a an adjustable drive means discharge efficiency of the fluid discharged from the nozzle.

The present invention is also a devised printing apparatus for achieving the above object.
That is, a fluid ejecting device for printing is provided, and the fluid ejecting device is arranged so as to form a pressure chamber having a nozzle capable of projecting a fluid in the chamber, a plurality of diaphragms , and each diaphragm. And a plurality of support portions for deformably supporting the diaphragm and two electrodes for deforming the diaphragm by an electrostatic force to change the pressure of the fluid, and at least one of the two electrodes is divided into a plurality of individual electrodes. An electrode pair; and a driving means capable of independently driving each individual electrode of the electrode pair and adjusting a discharge efficiency of the fluid discharged from the nozzle by changing a drive timing of the individual electrode to be driven. that Yusuke.

According to the functional element having the above configuration, the method for manufacturing the functional element having the above procedure, the fluid ejection device having the above configuration, and the printing apparatus having the above configuration, the plurality of struts that support the diaphragm are the most recent of the plurality of struts. Strut columns drawn by connecting things beside each other are arranged in a ring shape. Here, “annular” refers to a shape that draws a ring, but includes not only a circular shape but also an elliptical shape, a rectangular shape, and a polygonal shape. In addition to the case, a single case is also included. Furthermore, in addition to the case where the ring is closed, the case where a part of the ring is open is also included. Examples of the case where a part of the ring is open include a case where the ring has a spiral shape and a case where a part of the ring is interrupted.
If the column of columns is arranged in such a ring shape, for example, even when the diaphragm is formed in a circular shape or a rectangular shape, a plurality of columns are arranged corresponding to the shape of the diaphragm. become. In other words, since the plurality of support columns support the diaphragm, the repulsive force of the diaphragm can be sufficiently secured. Moreover, since the ring drawn by the column of columns corresponds to the shape of the diaphragm, for example, if the diaphragm is circular, each column can be arranged in multiple circles, or each column can be arranged in a spiral. Thus, even when the deflection of the diaphragm is divided into portions due to the presence of the support columns, the unit of the division is in accordance with the shape of the diaphragm such as a multiple circular shape or a spiral shape. That is, since the diaphragm can be bent for each division unit according to the shape of the diaphragm, the diaphragm can be vibrated efficiently.

According to the present invention, since the rigidity of the diaphragm is ensured by the presence of the plurality of support columns and a sufficient repulsive force is obtained, even if the short side length of the diaphragm is large, the diaphragm is deformed and the fluid is A sufficient pressure change can be given when a pressure change is applied to the. In addition, since the plurality of support columns are annularly arranged, the diaphragm can be efficiently vibrated.
For these reasons, when the present invention is used, for example, when an image is printed by ejecting ink droplets, the short side length of the diaphragm is increased to increase the in-plane density on the printed image. Therefore, it is possible to easily cope with the increase in the density of ink liquid discharge. Furthermore, the diaphragm for applying a pressure change to the ink liquid, which is a fluid, can be vibrated efficiently, so that the ink liquid is discharged without increasing power consumption and without reducing the ink discharge performance. It becomes possible. Therefore, it is possible to sufficiently meet demands such as higher image quality of printed images and faster printing output.
That is, by using the present invention, it is possible to easily cope with a high density arrangement, and it is possible to obtain an efficient fluid discharge characteristic even in the case of a high density arrangement.

  Hereinafter, a functional element and a manufacturing method thereof, a fluid ejection device, and a printing device according to the present invention will be described with reference to the drawings.

[Description of fluid ejection device and printing device]
First, prior to the description of the functional element, a fluid ejection device and a printing apparatus configured using the functional element will be described.

  First, the printing apparatus will be described. As an example of the printing apparatus, an ink jet printer apparatus is known. FIG. 1 is an explanatory diagram showing an outline of an ink jet printer apparatus. The ink jet printer device prints out a photographic quality printed matter at a high speed by discharging ink liquid into fine particles and ejecting it onto a sheet. Such an ink jet printer apparatus is roughly classified into a serial head type and a line head type.

In the case of the serial head type, as shown in FIG. 1A, a paper 2 as a printing object is mounted on a roller 2 that feeds the paper 1 in the main scanning direction, and a carriage 3 that can move in the sub-scanning direction of the paper 1. The inkjet head 4 is provided. The inkjet head 4 ejects ink liquid onto the paper 1 while moving the paper 1 and the carriage 3 to perform print output.
On the other hand, in the line head type, as shown in FIG. 1B, the roller 2 that feeds the paper 1 in the main scanning direction, and the ink liquid ejection port in a line shape along the sub-scanning direction of the paper 1 And an ink jet head 5 disposed in the head. Then, printing is performed by ejecting ink liquid from each ejection port of the inkjet head 5 onto the paper 1 while moving the paper 1.
The above-described configuration of the ink jet printer apparatus is an example of a printing apparatus, and does not stick to this configuration as long as printing can be performed by changing the relative positions of the head unit for ejecting liquid droplets and the printing object. .

  By the way, in order to meet the need to print even higher image quality at high speed, whether it is a serial head or a line head system, the inkjet printer device does not increase power consumption, but reduces the ejection performance. In addition, it is required to further increase the number of pixels. In order to meet such a demand, some inkjet printer apparatuses are configured using inkjet heads 4 and 5 based on electrostatic MEMS. In the electrostatic MEMS system, the ink jet heads 4 and 5 are configured using functional elements having a function as a vibration actuator, and the vibration due to the function is used as a pressure applying unit to the sheet 1. The ink liquid is discharged. The constituent elements other than the ink jet heads 4 and 5 in the ink jet printer apparatus may be realized by a known technique, and the description thereof is omitted here.

  Next, a specific example of a fluid ejection device configured using an inkjet head, that is, a functional element, used in an inkjet printer apparatus will be described. However, here, only the main part of an ink jet head as a fluid ejection device configured using functional elements will be described regardless of whether the serial head method or the line head method is used. 2 to 4 are schematic views showing a configuration example of a main part of an ink jet head to which the present invention is applied. FIG. 2 is a perspective view thereof, FIG. 3 is a plan view thereof, and FIG.

  As shown in FIG. 2, the ink jet head described here includes a microfluidic drive unit 10 and a fluid supply unit 20 when roughly classified. Among them, the microfluidic drive unit 10 is formed by arranging a plurality of diaphragms 11 driven (vibrated) by electrostatic force at high density, and functions as a vibration actuator when the diaphragms 11 are driven. Is. On the other hand, the fluid supply unit 20 is disposed on the microfluidic drive unit 10 and has a pressure chamber (so-called cavity) 22 in which an ink liquid 21 that is a fluid is stored, and a flow serving as an outer wall for forming the pressure chamber 22. A road wall 23 and a nozzle plate 24, and a discharge portion (so-called nozzle) 25 for discharging the ink liquid 21 in the pressure chamber 22 to the outside are provided.

As shown in FIGS. 3 to 4, in the microfluidic drive unit 10, the substrate side electrode 13 made of a conductive material thin film is formed on the substrate 12, and the insulating film 14 is formed on the surface of the substrate side electrode 13. The diaphragm-side electrode 16 and the diaphragm 11 are integrally disposed so as to face the substrate-side electrode 13 with a hollow structure space (hereinafter referred to as “hollow structure portion”) 15 interposed therebetween. A plurality of support columns 17a are formed on the substrate 12 so as to be supported by the doubly supported beams.
In these figures, the substrate side is a common electrode, and the plurality of individual electrodes are independently driven on the diaphragm side, but the electrode configuration on the substrate side and the diaphragm side may be reversed.

  Of these, the substrate 12 may be, for example, a substrate in which an insulating film 12b made of a silicon oxide film or the like is formed on a silicon substrate 12a. In addition, an insulating film may be formed on a semiconductor substrate such as gallium arsenide (GaAs). It is also possible to use an insulating material such as a glass substrate including a quartz substrate or a glass substrate including a quartz substrate.

  The substrate side electrode 13 may be formed of, for example, a polycrystalline silicon film doped with impurities, but may be a metal film (for example, a deposited film of Pt, Ti, Al, Au, Cr, Ni, Cu, etc.) or ITO (Indium). (Tin Oxide) film or the like may be used. Similarly, the diaphragm side electrode 16 may be formed of an impurity-doped polycrystalline silicon film, a metal film, an ITO film, or the like.

  The diaphragm 11 is formed of an insulating film, but is preferably formed of a silicon nitride film (SiN film) that can obtain a particularly high repulsive force. However, the diaphragm 11 is formed by stacking these respective films, with silicon oxide films formed on the upper and lower surfaces of the SiN film. In addition, as will be described in detail later, the diaphragm 11 is formed by concentrically arranging a plurality of planar shapes formed in a circular shape, a rectangular shape, or a polygonal shape. In FIG. 4, the case where the diaphragm 11 is doubly concentrically arranged is given as an example.

  The diaphragm 11 is supported by a plurality of support columns 17a formed at predetermined intervals (inter-support column pitch). However, there are a narrow pitch and a wide pitch in the pitch between the columns. The narrow pitch is preferably 2 μm or more and 10 μm or less, and most preferably about 5 μm. On the other hand, the wide pitch is preferably 15 μm or more and 35 μm or less, and most preferably about 25 μm. In this way, if the columns 17a are arranged at a pitch between columns having a narrow pitch and a wide pitch, the influence of the warp of the diaphragm 11 does not reach the entire circumference of the column 17a as in the case of a uniform pitch. The influence of the warp and operation of the adjacent diaphragm 11 becomes minor due to the narrowness of the pitch. As will be described in detail later, the plurality of support columns 17a are formed by connecting columns adjacent to each other with a narrow pitch, and the planar shape of the support columns 17a is circular, square, or polygonal. It is assumed that a plurality of items are arranged in a ring shape.

  Adjacent ones of the plurality of diaphragms 11 are continuously formed via the support pillars 17 a, and the support pillars 17 a are also integrally formed of the same material as the diaphragm 11. Therefore, the hollow structure portion 15 constituting the space between the diaphragm 11 and the substrate-side electrode 13 is communicated between the plural diaphragms 11 arranged in parallel, and is formed to be a sealed space. It will be a thing.

  Further, an opening used when performing sacrificial layer etching for forming the hollow structure portion 15 in the vicinity of the struts 17a of each diaphragm 11, for example, between the struts 17a along the concentric direction of one diaphragm 11. 18 is formed. Since the size of the opening 18 is likely to be closed as it is smaller, it can be considered to be □ 2 μm or less. However, if sacrificial layer etching is dry etching, □ 0.5 μm is sufficient.

The opening 18 is closed by the sealing film 19 after the sacrifice layer etching. It is conceivable that the opening 18 is sealed by the sealing film 19 by vapor deposition, sputtering, or PECVD (plasma-enhanced chemical vapor deposition). Further, as a material for forming the sealing film 19, aluminum (Al), nickel (Ni), chromium (Cr), copper (Cu), titanium (Ti), molybdenum (Mo), silver are used because of the ease of molding. (Ag), cobalt (Co), tantalum (Ta), platinum (Pt), gold (Au), tungsten (W), metals (such as silicon) and alloys thereof, oxide films such as SiO ₂ , or Although a nitride film etc. are mentioned, ceramics, resin, etc. previously formed can also be joined and used.

  A diaphragm side electrode 16 is joined to the diaphragm 11 via an insulating film, and the diaphragm side electrode 16 is arranged so as to be inserted into a bent lower surface recess of the diaphragm 11. It shall be installed. Further, below the diaphragm 11, in order to increase the repulsive force when the diaphragm 11 is thinly formed, the auxiliary strut (so-called post) 17 b is provided in the vicinity of the central portion thereof together with the strut (so-called anchor) 17 a. May be formed.

  The micro fluid driving unit 10 and the fluid supply unit 20 constitute an ink jet head.

  Here, the processing operation in the ink jet head having the above configuration will be described. In the ink jet head, when a required voltage is applied between the substrate side electrode 13 and the diaphragm side electrode 16 in the microfluidic drive unit 10, an electrostatic attractive force is generated between the electrodes as shown in FIG. Thus, the diaphragm 11 integrated with the diaphragm side electrode 16 is bent toward the substrate side electrode 13. On the contrary, when the voltage application between the substrate side electrode 13 and the diaphragm side electrode 16 is released, the diaphragm 11 is released from the electrostatic attraction as shown in FIG. Damping vibration. In the inkjet head, the ink liquid 21 in the pressure chamber 22 is discharged from the nozzle 25 to the outside and penetrates into the pressure chamber 22 due to the volume fluctuation of the pressure chamber 22 in the fluid supply unit 20 due to the vertical vibration of the vibration plate 11. The ink liquid 21 is supplied through the holes.

  At this time, when the vibration plate 11 bends toward the substrate side electrode 13, the hollow structure portion 15 is a closed space, so the air in the hollow structure portion 15 is compressed and attempts to inhibit the deformation of the vibration plate 11. To do. However, if the diaphragm 11 is a support structure using the support column 17a, the auxiliary support column 17a, etc., the air compressed in the hollow structure portion 15 under the adjacent diaphragm 11 can be released, and as a result, the diaphragm can be sufficiently used. 11 can be bent.

[Description of functional elements]
Next, the functional element used in the ink jet head having the above configuration, that is, the functional element according to the present invention will be described in more detail. As described above, the functional elements include all elements having a function as a vibration actuator. As an example, there are elements used in an ink jet head, that is, those shown in FIGS. FIG. 6 is an explanatory diagram showing an example of a schematic configuration of a functional element according to the present invention, FIG. 7 is an explanatory diagram showing an example of a main configuration thereof, and FIG. 8 is an explanatory diagram showing an arrangement example thereof.

  As shown in FIG. 6, in the functional element described here, a substrate-side electrode 13 is formed on a substrate 12, an insulating film 14 is formed on the surface of the substrate-side electrode 13, and this substrate-side electrode 13 is opposed. In this way, the diaphragm-side electrode 16 and the diaphragm 11 are integrally disposed with the hollow structure portion 15 interposed therebetween, and further, a support column 17a is formed on the substrate 12 so as to support each diaphragm 11 with a doubly supported beam. The fluid drive unit 10 is configured. A required voltage is applied between the substrate side electrode 13 and the diaphragm side electrode 16 to generate an electrostatic attractive force between the electrodes, thereby vibrating the diaphragm 11 integrated with the diaphragm side electrode 16. It has become possible to let you. That is, with these configurations, the microfluidic drive unit 10 functions as a vibration actuator.

  Further, a pressure chamber 22 is formed above the microfluidic drive unit 10 by the flow path wall 23 and the nozzle plate 24, and a pressure change is given to the pressure chamber 22 by the vibration of the vibration plate 11. Yes. That is, the pressure change in the pressure chamber 22 due to the vertical vibration of the vibration plate 11 causes the ink liquid 21 in the pressure chamber 22 to be discharged from the nozzle 25 to the outside, and the supply of the ink liquid 21 into the pressure chamber 22. Is done.

  By the way, in the functional element described here, as a characteristic configuration, the diaphragm 11 and the support column 17a are configured as described below.

  That is, the entire planar shape of the diaphragm 11 is a circular shape as shown in FIGS. 7A to 7C, a square shape as shown in FIG. 7D, or FIGS. It is formed in any polygonal shape as shown in f).

  Further, as described above, the columns 17a that support the diaphragm 11 are arranged at a pitch between columns having a narrow pitch and a wide pitch, and column columns drawn by connecting adjacent ones at the narrow pitch. In other words, the support columns drawn by connecting the nearest neighbors are arranged in a ring shape. Here, “annular” refers to a shape that draws a ring, but includes not only a circular shape but also an elliptical shape, a rectangular shape, and a polygonal shape. In addition to the case, a single case is also included. Furthermore, in addition to the case where the ring is closed, the case where a part of the ring is open is also included. Examples of the case where a part of the ring is open include a case where the ring has a spiral shape and a case where a part of the ring is interrupted. Specifically, as shown in FIG. 7A, when the column of support columns 17a has a multi-circular shape (in the illustrated example, a quadruple shape), the column of support columns 17a has a clothoid curve as shown in FIG. 7B. As shown in FIG. 7C, the column of columns 17a has a substantially multi-circular shape (in the example shown, a quadruple shape). However, when there is a discontinuous part in the part, as shown in FIG. 7D, when the column of the columns 17a has a multiple square shape (in the example shown in FIG. 7D), FIG. As shown in FIG. 7, when the columns of support columns 17 a have a multi-hexagonal shape (in the example shown, a quadruple hexagonal shape), the columns of support columns 17 a have a multi-octagonal shape (in the illustrated example, a quadruple octagonal shape). Cases can be considered.

  In the case of such an arrangement of the support columns 17a, the substrate side electrode 13 and the diaphragm side electrode 16 which are opposed to each other with the hollow structure portion 15 formed by the support columns 17a also correspond to the arrangement of the support columns 17a. It is desirable that they are arranged. That is, it is desirable that at least one of the substrate-side electrode 13 and the diaphragm-side electrode 16 is provided in a plurality corresponding to the ring drawn by the column of the columns 17a, and each can be driven independently.

  Specifically, as shown in FIG. 7A, if the columns of columns 17a are multi-circular, at least one of the substrate-side electrode 13 and the diaphragm-side electrode 16 is arranged in the column of columns 17a. For example, it is possible to drive the diaphragms 11 divided by the columns of the columns 17a individually on the inner peripheral side and the outer peripheral side. Further, as shown in FIG. 7B, when the columns of the support columns 17a are spiral, at least one of the substrate side electrode 13 and the diaphragm side electrode 16 has a width corresponding to the wide pitch of the support columns 17a. The rectangular plates having a predetermined length are arranged so as to be arranged along the columns of the columns 17a, and the respective diaphragms 11 corresponding to the sizes of the respective rectangular shapes are arranged, for example, near the periphery of the center of the spiral. It is conceivable that each can be driven individually.

  In order to enable the electrode pair composed of the substrate side electrode 13 and the diaphragm side electrode 16 to be independently driven, a switching circuit or the like for individually applying a voltage may be used. Good. Further, the electrode pair only needs to be provided with a plurality of at least one of the substrate side electrode 13 and the diaphragm side electrode 16. Therefore, for example, as shown in FIG. 6A, a plurality of substrate side electrodes 13 may be provided as common electrodes, and a plurality of diaphragm side electrodes 16 may be provided as individual electrodes, thereby forming an electrode pair. Alternatively, for example, FIG. As shown in b), a plurality of substrate-side electrodes 13 may be provided as individual electrodes, and the diaphragm-side electrode 16 may be a common electrode, thereby forming an electrode pair.

  In the functional element configured as described above, the diaphragm 11 is deflected by electrostatic force, and the restoring force is used as a driving force, whereby the ink liquid 21 that is the fluid in the pressure chamber 22 is accurately controlled and the nozzle. 25 can be discharged to the outside. Furthermore, since the planar shape of the diaphragm 11 is formed in a circular shape, a square shape, or a polygonal shape, the pressure chamber 22 is also formed in a shape corresponding to this, for example, the diaphragm is a strip-shaped vibration. Compared with the case where the actuators are arranged side by side and the nozzles are arranged in a line, the flow path resistance is 1/10 or less, and the occupied area per vibration actuator can be reduced. Therefore, for example, as shown in FIG. 8, a plurality of pressure chambers 22 can be regularly arranged with the supply path 30 of the ink liquid 21 interposed therebetween, so that the vibration actuator area can be reduced by the same amount. The number of actuators that can be arranged in the plane increases, and when applied to an inkjet head, it is easy to increase the density of the nozzle arrangement by increasing the in-plane density on the printed image. In addition, even if the planar shape of the diaphragm 11 is formed in a circular shape, a square shape, or a polygonal shape, the diaphragm 11 is supported by the plurality of support columns 17a, so that the repulsive force of the diaphragm 11 is sufficiently increased. It can be secured.

  In addition, the plurality of support columns 17a that support the diaphragm 11 are arranged so that the columns of columns to be drawn are annular. That is, for example, if the diaphragm 11 is circular, the planar shape of the diaphragm 11 is circular, square, or the like. For example, the pillars 17a are arranged in multiple circles, or the pillars 17a are arranged spirally. Or even if it is formed in a polygonal shape, a plurality of columns 17a are arranged corresponding to the shape. This is because even when the deflection of the diaphragm 11 is divided into portions due to the presence of the support pillars 17a, the division unit is a diaphragm such as a multiple circular shape, a spiral shape, a multiple square shape, or a multiple polygon shape. This means that it conforms to the eleventh shape. Accordingly, since the diaphragm 11 can be bent for each division unit in accordance with the shape of the diaphragm 11, the diaphragm 11 can be vibrated efficiently.

  In particular, when at least one of the electrode pairs composed of the substrate-side electrode 13 and the diaphragm-side electrode 16 is provided in correspondence with the ring drawn by the column of the support columns 17a and each can be driven independently, It becomes possible to perform drive control as described in (1), and the diaphragm 11 can be vibrated still more efficiently.

  For example, when each of a plurality of electrode pairs is driven independently, the diaphragm 11 gives the ink liquid 21 that is a fluid in the pressure chamber 22 by switching the number of electrode pairs to be driven. The amount of work can be adjusted. Specifically, in the case of ejecting a large amount of ink liquid 21 from the nozzle 25, the number of electrode pairs to be driven is increased, and a large number of division units in the diaphragm 11 are deflected, while a small amount of ink is ejected from the nozzle 25. In the case of discharging the liquid 21, it is possible to perform drive control such that the number of electrode pairs to be driven is reduced and only a part of the division unit in the diaphragm 11 is bent. That is, since the area where the vibration plate 11 bends can be changed according to the required discharge amount, the ink liquid 21 can be discharged efficiently, and the power consumption can be reduced.

  In addition, for example, when each of a plurality of electrode pairs is driven independently, the vibration liquid 11 is an ink liquid that is a fluid in the pressure chamber 22 by making the drive timing different for each electrode pair. It is also possible to match the phases of the work given to 21 at specific positions. As can be seen from FIG. 7, when the columns of columns 17a are annular and each diaphragm 11 divided thereby can be driven individually for each division unit, from the nozzle 25 to each division unit. The distance is different, and the distance increases as it goes to the outer periphery. Therefore, when ejecting the ink liquid 21 from the nozzle 25, if each of the divided units is driven at the same time, a phase difference due to a distance difference to the nozzle 25 is generated, so that the ejection efficiency of the ink liquid 21 is lowered. From this, the nozzle 25 is defined as a specific position, and a phase difference is given in advance to the driving of each division unit at a level of several tens of nanoseconds (nsec) so that the phases coincide at the specific position, and the division is farther than the specific position. By restoring the unit deflection first, it is possible to efficiently eject the ink liquid 21 and to reduce power consumption.

  From these facts, if the plurality of support columns 17a supporting the diaphragm 11 are arranged in an annular shape, the diaphragm 11 can be vibrated efficiently, so that the power consumption is not increased and the ejection performance of the ink liquid 21 is improved. It can be said that the ink liquid 21 can be discharged without dropping. Therefore, if the functional element configured as described above is used, it is possible to easily cope with a high density arrangement, and an efficient discharge characteristic of the ink liquid 21 can be obtained even in the case of a high density arrangement. is there.

  Further, for example, as shown in FIG. 7C, if the part of the ring drawn by the column of columns 17a is interrupted, and the interrupted part is matched with the communication port with the supply path 30, the ink liquid In addition to the discharge characteristics of the ink 21, the supply of the ink liquid 21 into the pressure chamber 22 can change the cross-sectional area in the vicinity of the communication port by driving control of the electrode pair, that is, driving the diaphragm 11. Can be performed well.

[Description of Method for Manufacturing Functional Element]
Next, a method for manufacturing the functional element configured as described above will be described. However, only the outline of the manufacturing procedure of the functional element will be described here, and the details of the thin film forming technique used in the manufacturing process are substantially the same as those in the past, and the publicly known technique can be used. Is omitted.

  In manufacturing the functional element, first, the substrate side electrode 13 is formed on the substrate 12, the insulating film 14 is formed on the surface of the substrate side electrode 13, and the sacrificial layer is further sacrificed on the substrate side electrode 13 via the insulating film. Form a layer. As the sacrificial layer, for example, a polycrystalline silicon film may be deposited by a CVD method.

  Then, a portion where the column 17a that supports the diaphragm 11 to be formed later is to be formed and a sacrificial layer corresponding to the auxiliary column 17b are selectively removed by etching to form an opening. The etching at this time is preferably dry etching. Moreover, the etching with respect to the part which should form the support | pillar 17a is performed with the etching pattern corresponding to the cyclic | annular form mentioned above.

  Thereafter, the diaphragm-side electrode 16 is formed on the sacrificial layer via an insulating film, and the diaphragm 11 and the struts 17a and the auxiliary struts 17b continuous to the sacrificial layer and the entire surface in the opening are insulated with the same insulation. It is formed by a film. These diaphragm 11, support column 17a, and auxiliary support column 17b may be formed of, for example, a silicon nitride film (SiN film) by a low pressure CVD method. This is because a tensile stress is generated in the SiN film, and the repulsive force of the diaphragm 11 is increased, which is convenient. Then, an insulating film having hydrophilicity with the ink liquid 21 is formed on the surfaces of the vibration plate 11, the support column 17a, and the auxiliary support column 17b. As a result, the diaphragm 11 is sandwiched between insulating films, which forms a laminated structure of a SiN film having tensile stress and an insulating film having compressive stress (for example, a silicon oxide film). This is effective in preventing warpage of the diaphragm 11.

  After the diaphragm 11 is formed in this manner, subsequently, an opening 18 is formed so that the sacrificial layer is exposed through the laminated structure of the diaphragm 11 and the insulating film. Then, the sacrificial layer is removed by sacrificial layer etching through the opening 18, and the opening 18 is further closed with a sealing film 19. Thereby, the hollow structure part 15 is formed, and the support | pillar 17a is distribute | arranged circularly in the hollow structure part 15. FIG. However, the hollow structure portion 15 may be formed by other known forming methods instead of sacrificial layer etching. In addition, the film thickness of the vibration plate 11 is determined in consideration of the bending and stress generated by etching the sacrificial layer, the bending and stress generated by forming the sealing film 19, and the like.

  In addition, the opening 18 used for forming the hollow structure portion 15 is blocked by the sealing film 19. In order to prevent intrusion of outside air, fluid, or the like on the sealing film 19. The cover layer may be formed. This is because if the sealing film 19 is covered with the cover layer, the sealing of the opening 18 by the sealing film 19 becomes even more reliable. As such a cover layer, a plasma silicon nitride (PE-SiN) film that has excellent moisture resistance and is effective in preventing intrusion of a fluid or the like can be considered. However, the cover layer is not necessarily required and may not be formed. Even in the case of film formation, the cover layer is not necessarily a single layer such as a PE-SiN film, and may be a multilayer.

  Thereafter, for example, a photocurable resin material layer, for example, an epoxy resin material layer having photosensitivity, is formed and patterned using a lithography technique, and the flow path wall 23 of the pressure chamber 22 and the fluid communicating with the pressure chamber 22 are formed. The supply flow path (not shown) is formed. That is, the pressure chamber 22 is formed on the diaphragm 11, and the flow path wall 23 is formed on both sides of the diaphragm 11. Then, a nozzle plate 24 formed of a required material such as a metal such as nickel or stainless steel, Si wafer, glass, or resin is bonded so as to close the upper portion of the pressure chamber 22. At this time, the pressure chamber 22 is preliminarily formed of glass or resin in a cross-sectional shape including the nozzles 25 as shown in FIGS. 9A to 9C, and this is soldered to the upper surface of the microfluidic drive unit 10. It may be formed by attaching by anodic bonding, anodic bonding, diffusion bonding, adhesion or the like. In the cross-sectional shape of the illustrated example, since the one shown in (a) is gradually narrower toward the nozzle 25 than the one shown in (c), there is less flow path resistance and less deflection of the nozzle surface. Good discharge efficiency can be obtained.

  The functional element is configured through the above procedure.

  In the series of embodiments described above, the case where the diaphragm 11 is supported by the plurality of support columns 17a and the columns of the support columns 17a are arranged in an annular shape has been described as an example. It is also conceivable to provide a single column wall instead of the column 17a. That is, it is also conceivable that a wall body continuous along the column of columns described above is provided as a column wall, and the column wall supports the diaphragm 11 in a deformable manner. Even in the case where such a support wall is provided, the diaphragm 11 can be vibrated efficiently if the support wall is arranged in an annular shape, so that it can easily cope with a high-density arrangement. At the same time, the ink liquid 21 can be ejected without degrading the ejection performance of the ink liquid 21 and without increasing the power consumption even in a high density arrangement.

[Description of other examples of functional elements]
In the above description of the embodiment, the case where the functional element is used in the ink jet head, that is, the case where the fluid ejection device is the ink jet head and the printing device is the ink jet printer device has been described as an example. It is not limited to these. For example, the functional element according to the present invention is not only a fluid ejection device such as an inkjet head, but also a micropump, μTAS (Micro Total Analysis Systems), a DNA chip, a thermal diffusion device, a speaker element, a diaphragm type sensor (for example, The present invention can also be applied to microphones, pressure sensors, etc. In addition to the inkjet head, the fluid ejection device according to the present invention is a coating device for a polymer or low molecular organic material such as an organic electroluminescent element, a printing device for printed circuit board wiring, a solder bump printing device, three-dimensional modeling. Equipment, DNA chip, μTAS as a supply head for controlling and supplying chemicals and other liquids with a minute unit of pl (picoliter) or less, and further supplying a gas with a minute amount of accurately controlled supply Can be applied.

  Here, as another embodiment according to the present invention, a case where the present invention is applied to a so-called micropump in which a microfluidic drive unit and a rectifying valve are combined will be described as an example. FIG. 10 is a schematic diagram illustrating an example of a main configuration of a micropump to which the present invention is applied.

  As shown in the figure, the micropump described here has a pressure chamber 44 communicating with a flow path 43 disposed on a vibration actuator 42 having a diaphragm 41 of an electrostatic MEMS method or a piezoelectric method. The fluid supply port and the fluid discharge port are respectively provided with rectifying valves 45a and 45b having anisotropic flow path resistance. The diaphragm 41 in the vibration actuator 42 is supported by a plurality of pillars (or pillar walls) 46 arranged in an annular shape. The fluid may be not only a liquid such as an ink liquid in an ink jet head but also a gas such as ambient air or a predetermined gas.

In the micropump having such a configuration, the following processing operation is performed. As shown in FIG. 10A, in the default state of the micropump, both the rectifying valves 45 a and 45 b are warped due to the stress difference, and the tip thereof is in contact with the ceiling of the pressure chamber 44. Then, as shown in FIG. 10B, when the diaphragm 41 is displaced downward and the pressure in the pressure chamber 44 decreases due to the increase in volume of the pressure chamber 44, the pressure difference generated between the rectifying valves 45a on both surfaces thereof. Therefore, the fluid flows into the pressure chamber 44 from the rectifying valve 45a side. Thereafter, as shown in FIG. 10C, when the vibration plate 41 is displaced upward and the pressure in the pressure chamber 44 increases due to the volume reduction of the pressure chamber 44, the rectifying valve 45 a has its tip at the pressure chamber 44. The rectifying valve 45b is bent and the fluid in the pressure chamber 44 is discharged while the fluid in the pressure chamber 44 is prevented from flowing back.
The rectifying valve is not limited to this method as long as the flow resistance has anisotropy.

  A micropump that performs such processing operation may be used as a cooling pump for LSI (Large Scale Integration), for example. That is, when used as an LSI cooling pump, a fluid functioning as a refrigerant can be circulated according to the amount of heat generated from the LSI. At this time, in the configuration of the micropump described above, intake or exhaust is performed through a nozzle configured in the same manner as in the case of the ink jet head or a valve corresponding thereto, but in the intake, gas is supplied from all directions. In contrast to suction, when exhausting (discharging), a velocity vector is generated only in the direction perpendicular to the surface of the nozzle plate or the like, so if a cooling object is placed near the nozzle, the cooling object On the other hand, high-speed gas can be blown. Further, if this cooling method is used, a rectifying valve is not necessary, and there may be one fluid inlet / outlet to the pressure chamber.

  Also in the micro pump as described above, the support plate (or support wall) 46 supporting the vibration plate 41 can be arranged in an annular shape so that the vibration plate 41 can be vibrated efficiently, so that it can easily cope with a high density arrangement. In addition, even in the case of high density arrangement, it is possible to discharge the gas without reducing the gas discharge performance and without increasing the power consumption.

  As described above, the fluid to which the diaphragm gives a pressure change is not limited to the ink liquid (liquid) as in the case of the ink jet head described above, but is a gas as in the case of the micropump described here. It doesn't matter.

[Description of still another example of functional element]
Next, as another embodiment of the present invention, a case where the present invention is applied to a speaker will be described as an example. FIG. 11 is a schematic diagram illustrating an example of a main configuration of a speaker to which the present invention is applied.

  As shown in the figure, in the speaker described here, a substrate-side electrode 52 is formed on a substrate 51, and a diaphragm-side electrode 54 and a diaphragm are sandwiched by sandwiching a hollow structure portion 53 so as to face the substrate-side electrode 52. 55 is integrally formed, and a support 56 is formed on the substrate 51 so as to support the diaphragm 55, and a support column drawn by the support 56 is arranged in an annular shape. A required voltage is applied between the substrate-side electrode 52 and the diaphragm-side electrode 54 to generate an electrostatic attractive force between the electrodes, thereby vibrating the diaphragm 55 integrated with the diaphragm-side electrode 54. It has become possible to let you. In other words, these configurations function as a speaker that vibrates the diaphragm 55 and outputs sound. In the case of such a speaker, it is desirable to make the diaphragm 55 thinner and to set the resonance frequency to about 100 kHz than in the case of the ink jet head described above.

  Also in the speaker as described above, by arranging the columns of columns 56 supporting the diaphragm 55 in an annular shape, the diaphragm 55 can be efficiently vibrated, so that it can easily cope with a high-density arrangement, Even in the case of density arrangement, it is possible to output the sound without deteriorating the sound output characteristic (vibration performance) and without increasing the power consumption.

  Further, by switching between driving and detection with substantially the same structure as the above-described speaker, practical use as a condenser microphone becomes possible. That is, the functional element according to the present invention may be one in which the diaphragm is deformed by a change in fluid pressure, and a change in capacitance due to the deformation is detected by the electrode pair.

  As described above, the present invention can be applied to various things. That is, the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.

It is explanatory drawing which shows the outline | summary of an inkjet printer apparatus. FIG. 2 is a perspective view schematically showing a configuration example of a main part of an ink jet head to which the present invention is applied, as a specific example of a fluid ejection device according to the present invention. FIG. 2 is a plan view schematically showing a configuration example of a main part of an ink jet head to which the present invention is applied. FIG. 4 is a side cross-sectional view (part 1) schematically showing a configuration example of a main part of an ink jet head to which the present invention is applied, and a cross-sectional view taken along line AA in FIG. It is explanatory drawing which shows typically the outline | summary of the processing operation in the inkjet head to which this invention was applied. It is explanatory drawing which shows an example of schematic structure of the functional element which concerns on this invention. It is explanatory drawing which shows an example of the principal part structure of the functional element which concerns on this invention. It is explanatory drawing which shows the example of arrangement | positioning of the functional element which concerns on this invention. It is explanatory drawing which shows the specific example of the pressure chamber shape in the functional element which concerns on this invention. It is the other specific example of the fluid discharge apparatus which concerns on this invention, and is a schematic diagram which shows an example of the principal part structure of the micropump to which this invention was applied. It is another specific example of the fluid ejection device according to the present invention, and is a schematic diagram showing an example of a main configuration of a speaker to which the present invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Paper, 2 ... Roller, 3 ... Carriage, 4, 5 ... Inkjet head, 10 ... Micro fluid drive part, 11 ... Vibrating plate, 12 ... Substrate, 13 ... Substrate side electrode, 14 ... Insulating film, 15 ... Hollow structure Part 16: Diaphragm side electrode, 17a ... Column (anchor), 17b ... Auxiliary column (post), 18 ... Opening, 19 ... Sealing membrane, 20 ... Fluid supply unit, 21 ... Ink liquid, 22 ... Pressure chamber ( Cavity), 23 ... Flow path wall (wall body), 30 ... Supply path, 41 ... Vibration plate, 42 ... Vibration actuator, 43 ... Flow path, 44 ... Pressure chamber, 45a, 45b ... Rectifier valve, 46 ... Strut, 51 ... Substrate, 52 ... Substrate side electrode, 53 ... Hollow structure portion, 54 ... Diaphragm side electrode, 55 ... Diaphragm, 56 ... Still

Claims (17)

A plurality of diaphragms;
A plurality of support portions that are arranged to be annular with respect to the plurality of diaphragms and support each of the diaphragms in a deformable manner;
An electrode pair in which the diaphragm is deformed by an electrostatic force to apply a pressure change to the fluid, and at least one of the two electrodes is divided into a plurality of individual electrodes;
Each individual electrode of the electrode pair can be driven independently, and by changing the drive timing of the individual electrode to be driven, each phase of pressure change applied to the fluid by each of the plurality of individual electrodes can be matched at a specific position functional element that having a drive means. The driving means calculates a phase difference of a pressure change in the fluid generated by a difference in distance between each driven individual electrode and the specific position of the fluid when driving each of the plurality of individual electrodes independently. Each individual electrode is driven at different drive timings so that it is not at a specific position.
The functional element according to claim 1 . The driving means adjusts the amount of work applied to the fluid by the diaphragm by switching the number of the individual electrodes to be driven when driving the plurality of individual electrodes.
The functional element according to claim 2 . Each of the plurality of support portions includes a plurality of support columns, and the support column drawn by connecting the closest ones of the support columns is arranged in an annular shape.
The functional element according to claim 2 or 3 . Each of the plurality of support portions is composed of a continuous wall body, and each wall body is arranged in a ring shape.
The functional element according to claim 2 or 3 . The plurality of individual electrodes are arranged so as to draw a multiple ring along the annular column column or the wall body .
The functional element according to claim 4 or 5 . A plurality of diaphragms, a plurality of support portions that are annularly arranged with respect to the plurality of diaphragms , and each diaphragm is supported to be deformable, and the diaphragm is deformed by an electrostatic force to change the pressure of the fluid. The electrode pair in which at least one of the two electrodes is divided into a plurality of individual electrodes, and each individual electrode of the electrode pair can be independently driven, and the drive timing of the individual electrode to be driven is determined. by changing, when each of the plurality of individual electrodes forming the plurality of supporting portions of the functional elements that have a and matching possible drive means at a specific location each phase of the change in pressure applied to the fluid, each support that high-speed steel a part in such a manner that an annular
Method of manufacturing a function element. Each of the support portions is constituted by a plurality of support columns, and the plurality of support columns are arranged so that a column of support columns drawn by connecting the nearest ones of the support columns is annular.
A method for manufacturing a functional element according to claim 7 . Each of the support portions is constituted by a continuous wall body and is arranged so that the wall body is annular.
A method for manufacturing a functional element according to claim 7 . The plurality of individual electrodes are arranged so as to draw a multi-ring along the annular column column or the wall body.
A method for manufacturing a functional element according to claim 8 or 9 . A pressure chamber having a nozzle capable of projecting the fluid in the chamber;
A plurality of diaphragms;
A plurality of support portions that are arranged to be annular and support each diaphragm in a deformable manner;
An electrode pair in which the diaphragm is deformed by an electrostatic force to give a pressure change to the fluid, and at least one of the two electrodes is divided into a plurality of individual electrodes ;
Wherein is an electrode pair each individual electrode of the drivable independently by changing the drive timing of the individual electrodes to be driven, that having a an adjustable drive means discharge efficiency of the fluid discharged from the nozzle fluid Discharge device . The driving means calculates a phase difference of a pressure change in the fluid generated by a difference in distance between each driven individual electrode and the specific position of the fluid when driving each of the plurality of individual electrodes independently. Each individual electrode is driven at different drive timings so as not to be at the position of the nozzle.
The fluid ejection device according to claim 11 . The driving means adjusts the amount of work applied to the fluid by the diaphragm by switching the number of the individual electrodes to be driven when driving the plurality of individual electrodes.
The fluid ejection device according to claim 12 . Each of the plurality of support portions includes a plurality of support columns, and the support column drawn by connecting the closest ones of the support columns is arranged in an annular shape.
The fluid ejection device according to claim 12 or 13 . Each of the plurality of support portions is composed of a continuous wall body, and each wall body is arranged in a ring shape.
The fluid ejection device according to claim 12 or 13 . The plurality of individual electrodes are arranged so as to draw a multiple ring along the annular column column or the wall body .
The fluid ejection device according to claim 14 or 15 . A fluid ejection device for printing,
The fluid ejection device is
A pressure chamber having a nozzle capable of projecting the fluid in the chamber;
A plurality of diaphragms;
A plurality of support portions that are arranged to be annular and support each diaphragm in a deformable manner;
An electrode pair in which the diaphragm is deformed by an electrostatic force to give a pressure change to the fluid, and at least one of the two electrodes is divided into a plurality of individual electrodes ;
It can be driven to the individual electrodes of the electrode pairs independently, by changing the drive timing of the individual electrodes to be driven, that having a an adjustable drive means discharge efficiency of the fluid discharged from the nozzle indicia Printing device.

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