JP4655807B2 - Electrostatic actuator, droplet discharge head, and droplet discharge device - Google Patents

Description

The present invention is an electrostatic actuator, relates to a droplet discharge head and a droplet discharging equipment.

  In order to increase the printing speed and color, there is a demand for a droplet discharge head having a structure having a plurality of nozzle rows. In recent years, the nozzle density has been increased and the number of nozzles per row has increased. The number of actuators in the droplet discharge head is increasing more and more. Therefore, there is a demand for a small droplet discharge head having a high nozzle density, a long nozzle row, and an increased number of actuators.

  In such a droplet discharge head, when the substrates are anodically bonded, for example, the potential of the vibration plate provided on the cavity substrate is set equal to the potential of the individual electrode provided on the electrode substrate, and the individual electrodes vibrate at the time of bonding. Elimination of the potential difference from the plate is performed. In this way, the electric field disappears, discharge and field emission can be prevented, a large current can be prevented from flowing between the individual electrode and the diaphragm, and melting of the electrode can be prevented. In joining at this time, for example, an invention is disclosed in which a terminal, that is, an external lead wire is brought into contact with a common electrode provided on an electrode substrate, and the cavity substrate and the electrode substrate are anodic bonded. In this case, all the electrodes formed on the electrode substrate are connected to the common electrode via the lead portion in the wafer state at the time of bonding. For this reason, when the head is formed, a part of the electrode must be cut by dicing and the lead portion must be removed, and by doing so, the electrode corresponding to each actuator is individualized, and the individual electrode is separated. (For example, refer to Patent Document 1).

  In the invention of the conventional liquid discharge head disclosed in Patent Document 1, all the electrodes are connected in the wafer state at the time of bonding, and a part of the electrodes is cut during dicing to form individual electrodes. Since the layout structure is used, there is a restriction on the wiring layout structure. For example, the individual electrodes cannot be formed inside the dicing surface. For this reason, the droplet discharge head cannot be sufficiently miniaturized.

  In addition, in the droplet discharge head, there is an invention in which an equipotential contact constituting a common electrode is provided for each head chip in order to directly contact the electrode formed on the electrode substrate and the cavity substrate. That is, in the head chip manufacturing process, equipotential contacts are provided for each head chip of each droplet discharge head on the wafer, and the electrode substrate and the silicon substrate are brought into direct contact via the equipotential point, and then the anode In this case, it is not necessary to connect the silicon substrate and the equipotential contact with an external lead wire or the like, and a groove for connecting the equipotential point and each electrode portion is formed. (For example, refer to Patent Document 2).

JP 2002-283579 (page 12, FIG. 28) Japanese Patent Laying-Open No. 2004-306443 (9 pages, FIGS. 3 and 4)

  In the invention of the conventional liquid discharge head disclosed in Patent Document 2, as in the invention disclosed in Patent Document 1, all the electrodes in the head including the equipotential contact are connected at the time of bonding. Thus, during dicing, a part of the electrode is cut to form individual electrodes. For this reason, the wiring layout structure is limited, and the head cannot be sufficiently miniaturized.

The present invention has been made to solve the above-described problems, and provides an electrostatic actuator, a droplet discharge head, and a droplet capable of reducing the size of the head by providing flexibility in the electrode wiring layout. and to obtain the discharge equipment.

An electrostatic actuator according to the present invention includes a first substrate having a diaphragm, and a second substrate in which an electrode groove is formed and an individual electrode is provided in the electrode groove to face the diaphragm with a gap. In the electrostatic actuator formed by anodically bonding the first substrate and the second substrate, each individual electrode formed on the second substrate at the time of anodic bonding of the first substrate and the second substrate and the first substrate As an equipotential contact for electrically connecting to the substrate, the side wall of the electrode groove protrudes toward the center of the electrode groove to form a rising portion, and one of the lead portions of the individual electrodes is formed on the rising portion. In this configuration, the portion of each lead portion of each individual electrode that rides on the climbing portion is brought into direct contact with the first substrate . For this reason, even if the individually closed individual electrodes are wired in the electrostatic actuator, an equipotential can be ensured when the first substrate and the second substrate are joined.

  In the electrostatic actuator according to the present invention, the equipotential contact is formed by projecting a part of the individual electrode lead portion toward the first substrate. For this reason, even when individually closed individual electrodes are wired in the electrostatic actuator, the equipotential can be reliably and easily secured when the first substrate and the second substrate are joined.

In addition, a droplet discharge head according to the present invention includes an electrostatic actuator, the first substrate has a concave portion serving as a discharge chamber in which a bottom wall forms a vibration plate and retains a droplet, A nozzle substrate formed with a plurality of nozzle holes for discharging droplets, a recess serving as a common droplet chamber for supplying droplets to the discharge chamber, a through hole for transferring droplets from the common droplet chamber to the discharge chamber, and A reservoir substrate having a nozzle communication hole for transferring droplets from the discharge chamber to the nozzle hole, and an IC driver for supplying a drive signal to the individual electrode, wherein the second substrate, the first substrate, the reservoir substrate, and the nozzle substrate are It is formed by laminating. For this reason, a droplet discharge head can be reduced in size. Then, when joining the first substrate and the second substrate, when removing the portion of the first substrate that becomes an equipotential contact so as to become a through hole after anodic bonding, Individual electrodes can be easily made independent.

  A droplet discharge apparatus according to the present invention is equipped with the droplet discharge head described above. Therefore, it is possible to obtain a droplet discharge device in which the droplet discharge head is downsized.

Embodiment 1. FIG.
FIG. 1 is an exploded perspective view of a droplet discharge head according to Embodiment 1 of the present invention, and FIG. 2 is a longitudinal sectional view of a state in which the droplet discharge head of FIG. 1 is assembled. The droplet discharge heads shown in FIGS. 1 and 2 are of the face ink jet type that discharges droplets from nozzle holes provided on the surface side of the nozzle substrate, and are driven by electrostatic force. belongs to. As shown in the figure, the droplet discharge head 1 is composed of four substrates: an electrode substrate 2 (second substrate), a cavity substrate 3 (first substrate), a reservoir substrate 4, and a nozzle substrate 5. The nozzle substrate 5 is bonded to one surface of the reservoir substrate 4, and the cavity substrate 3 is bonded to the other surface of the reservoir substrate 4. The electrode substrate 2 is bonded to the surface of the cavity substrate 3 opposite to the surface where the reservoir substrate 4 is bonded. A driver IC 60 that supplies a drive signal to an individual electrode (described later) is provided inside the droplet discharge head 1.

  As shown in FIGS. 1 and 2, the electrode substrate 2 is made of glass such as borosilicate glass whose linear expansion coefficient approximates that of silicon, and a plurality of recesses (electrode grooves) 20 that are electrode chambers are fixed. The individual electrodes 22 are disposed in the recesses 20 so as to face the diaphragm (described later) of the cavity substrate 3. One end of the individual electrode 22 is connected to the driver IC 60, and a drive signal is supplied from the driver IC 60 to the individual electrode 22 to control the actuator.

  The recess 20 which is an electrode chamber has a slightly larger size similar to these shapes so that the individual electrode 22 and its lead part 23 (the individual electrode 22 and the individual electrode lead part 23 are collectively referred to as an electrode part) are provided in the recess 20. The individual electrodes 22 are provided with their long sides parallel to each other to form two rows of electrode rows A and B. An IC mounting recess 21 having the same depth as these recesses 20 communicates with the opposing recesses 20 in a shape orthogonal to the long side direction of the individual electrode 22, and the driver IC 60 is connected to the IC mounting recess 21. Has been implemented.

  Here, the configuration of the recess 20, the individual electrode 22, and the lead portion 23 provided in the electrode substrate 2 will be described in detail with reference to FIGS. 3, 4, and 5. 3 is a plan view of the main part of the electrode substrate 2 shown in FIGS. 1 and 2, FIG. 4 is a cross-sectional view taken along line AA in FIG. 3, and FIG. 5 is a cross-sectional view taken along line BB in FIG. As shown in the figure, each of the recesses 20 is formed of a substantially rectangular and wide first recess 20a and a narrow second recess 20b that communicate with each other in the longitudinal direction. The second concave portion 20b is arranged in communication with the IC mounting concave portion 21 so that the second concave portion 20b is substantially orthogonal to the second concave portion 20b. From the side wall on one side of the second recess 20b, a substantially rectangular parallelepiped post 24 that forms a rising portion of the electrode portion on the center side of the second recess 20b protrudes integrally with the electrode substrate 2. The upper surface of the post 24 has the same planar height as the upper surface of the electrode substrate 2.

  In each recess 20 provided in the electrode substrate 2, along the longitudinal direction, the individual electrode 22 and its lead portion 23 narrower than the first recess 20 a and the second recess 20 b are respectively provided on the cavity substrate 3. For example, ITO (Indium Tin Oxide) is formed by sputtering so as to face a diaphragm (described later). Note that the vicinity of the end portion of the lead portion 23 extends to the IC mounting recess 21 side, and can be connected to the driver IC 60 on the IC mounting recess 21 side.

  In the second recess 20b, the lead portion 23 of the individual electrode 22 is formed along the bottom surface of the second recess 20b, as shown in FIG. 5, but on the center side of the second recess 20b. At the position of the protruding post 24, as shown in FIG. 4, the equipotential contact 25 is formed so as to ride on the post 24 from the bottom surface of the second recess 20 b, that is, so as to rise above the upper surface of the electrode substrate 2. In the equipotential contact 25, the electrode portion of the electrode substrate 2 and the cavity substrate 3 can be brought into contact with each other at the time of anodic bonding so as to be in an equipotential state. In the above description, the equipotential contact 25 is integrated with the electrode substrate 2 by the substantially rectangular parallelepiped post 24 protruding from the side wall located on the same side of the second recess 20b toward the center of the second recess 20b. However, the post 24 may protrude from any side wall side of the second recess 20b to the center side, or may be provided near the center of the second recess 20b. Furthermore, the shape of the post 24 is not limited to a rectangular parallelepiped shape, and may be any shape such as a cubic shape or a cylindrical shape.

In this way, the driver IC 60 shown in FIGS. 1 and 2 is provided between the two electrode arrays A and B, and is connected to the electrode arrays A and B. B can be supplied with a drive signal, making it easy to increase the number of electrode rows. Moreover, since the number of driver ICs 60 is reduced by such a configuration, the cost can be reduced and the droplet discharge head 1 can be downsized. In the liquid droplet ejection head 1 shown in FIG. 1, two driver ICs 60 are installed. However, these driver ICs 60 may be constituted by one IC or by three or more ICs. Also good.
In the above configuration, as shown in FIG. 1, a droplet supply hole 70 a is formed in the electrode substrate 2, and the droplet supply hole 70 a penetrates the electrode substrate 2.

As shown in FIGS. 1 and 2, the cavity substrate 3 is made of, for example, single crystal silicon, and a recess 32 a that becomes a pressure chamber 32 that constitutes the vibration plate 30 is formed on the bottom wall. The recesses 32a are formed in two rows corresponding to the individual electrodes 22 (electrode rows A and B). Further, the cavity substrate 3 is provided with a first hole 33 penetrating the cavity substrate 3 between the recesses 32 a and a common electrode 34 for applying a voltage to the diaphragm 30. Reference numeral 34 is connected to the FPC 35. The cavity substrate 3 has an insulating film 31 made of TEOS (Tetra Ethyl Ortho Silicate) formed on the entire surface thereof by plasma CVD (Chemical Vapor Deposition). This is for preventing dielectric breakdown and short-circuiting when the diaphragm 30 is driven and for preventing etching of the cavity substrate 3 by droplets.
Further, the cavity substrate 3 is formed with a droplet supply hole 70 b penetrating the cavity substrate 3.
Further, a sealing material 71 for sealing the gap 73 is provided between the first hole 33 of the cavity substrate 3 and the recess 20 of the electrode substrate 2.

  As shown in FIGS. 1 and 2, the reservoir substrate 4 is made of, for example, single crystal silicon, and opposed to both sides in the width direction are concave portions 40 a serving as a common droplet chamber 40 for supplying droplets to the pressure chamber 32. A through hole 41 for transferring droplets from the common droplet chamber 40 to each pressure chamber 32 is provided on the bottom surface of the recess 40a. Further, a droplet supply hole 70c penetrating the bottom surface of the recess 40a is formed on the bottom surface of the recess 40a. The droplet supply hole 70c formed in the reservoir substrate 4, the droplet supply hole 70b formed in the cavity substrate 3, and the droplet supply hole 70a formed in the electrode substrate 2 are the reservoir substrate 4, the cavity substrate 3 and In a state where the electrode substrate 2 is bonded, the droplet supply holes 70 are formed so as to communicate with each other and supply droplets to the common droplet chamber 40 from the outside. Further, a second hole portion 42 penetrating the reservoir substrate 4 is formed between the common droplet chambers 40 facing the reservoir substrate 4. Note that the second hole portion 42 may be a hole portion having a reverse concave shape in cross section in which the nozzle substrate 5 side is closed without penetrating the reservoir substrate 4.

  The first hole portion 33 provided in the cavity substrate 3 and the second hole portion 42 provided in the reservoir substrate 4 communicate with each other, and the IC mounting recess 21 provided in the electrode substrate 2 further includes a housing portion. 72 is formed. The driver IC 60 is housed in the housing portion 72 in a state of being attached to the IC mounting recess 21. Further, between the concave portion 40 a of the reservoir substrate 4 and the second hole portion 42, the pressure chambers 32 communicate with the respective pressure chambers 32, and droplets are transferred from the pressure chambers 32 to nozzle holes (described later) of the nozzle substrate 5. Nozzle communication hole 35 is provided.

  As shown in FIGS. 1 and 2, the nozzle substrate 5 is made of a silicon substrate, and is provided with a plurality of nozzle holes 43 that communicate with the nozzle communication holes 35 of the reservoir substrate 4. In addition, the nozzle hole 43 is formed in two steps by a large diameter portion and a small diameter portion, and improves straightness when ejecting droplets.

  In the droplet discharge head 1 configured as described above, as shown in FIG. 2, the driver IC 60 is accommodated in the accommodating portion 72 and attached to the IC mounting recess 21 provided in the electrode substrate 2. The part 72 is closed by the nozzle substrate 5, the cavity substrate 3, the reservoir substrate 4, and the electrode substrate 2. That is, the nozzle substrate 5 covers the upper surface of the housing portion 72, the electrode substrate 2 covers the lower surface of the housing portion 72, and the cavity substrate 3 and the reservoir substrate 4 cover the side surfaces of the housing portion 72 so that the housing portion 72 is closed. It has become.

  Next, the operation of the droplet discharge head 1 will be described with reference to FIG. Droplets are supplied to the common droplet chamber 40 from the outside via a droplet supply hole 70. Further, the pressure chamber 32 is supplied with droplets from the common droplet chamber 40 through the through holes 41. A drive signal (pulse voltage) is supplied to the driver IC 60 from a control unit (not shown) of the droplet discharge device 1 via the IC wiring 36 of the FPC 35 and the lead wire 26 provided on the electrode substrate 2. . Then, a pulse voltage is applied from the driver IC 60 to the individual electrode 22 to positively charge the individual electrode 22, and a driving signal (from the control unit of the droplet discharge device is connected to the corresponding diaphragm 30 via the common electrode wiring 37. Supply a pulse voltage) and charge it negatively. Thereby, the diaphragm 30 is attracted to the individual electrode 22 by the electrostatic force and bent.

  Next, when the pulse voltage is turned off, the electrostatic force applied to the diaphragm 30 disappears and the diaphragm 30 is restored. At this time, the pressure inside the pressure chamber 32 rapidly increases, and the droplets in the pressure chamber 32 pass through the nozzle communication hole 35 and are discharged from the nozzle hole 43. Then, the pulse voltage is applied again, and the diaphragm 30 is bent toward the individual electrode 22, whereby the droplets are replenished from the common droplet chamber 40 into the pressure chamber 32 through the through hole 41.

In the droplet discharge head 1 described above, supply of droplets to the common droplet chamber 40 is performed by, for example, a droplet supply tube (not shown) connected to the droplet supply hole 70.
In the first embodiment, the FPC 35 is connected to the driver IC 60 so that the longitudinal direction thereof is parallel to the short side direction of the individual electrodes 22 forming the electrode array. Thereby, the droplet discharge head 1 having the plurality of electrode arrays A and B and the FPC 35 can be connected in a compact manner.

Next, the manufacturing process of the droplet discharge head 1 will be described with reference to FIG. Actually, a plurality of droplet discharge head members are simultaneously formed from a silicon wafer, but only a part thereof is shown in FIG.
First, a method for manufacturing the electrode substrate 2 made of a glass member will be described. As shown in FIG. 6A, for example, a resist is applied to the entire surface of the electrode substrate 2 and patterned into a predetermined shape, and then etched with a hydrofluoric acid aqueous solution or the like to match the shape pattern of the electrode portions 22 and 23. A recess 20 is formed. At this time, a resist process is performed so that the portion to be the post 24 of the equipotential contact 25 cannot be etched, and the portion of the post 24 is left without being etched at the time of etching. Thus, after forming the recess 20 and the post 24, the resist is peeled off.

Next, the electrode parts 22 and 23 are formed by sputtering ITO (Indium Tin Oxide) using, for example, a sputtering method. That is, the individual electrode 22 and its lead part 23 are formed from the first recess 20a to the second recess 20b. At that time, ITO is also formed on the portion to be the equipotential contact 25. Although the number of processes increases, a metal piece or the like may be attached to the equipotential contact 25 portion.
The droplet supply hole 70a (not shown) is formed by a drill or the like.

  Next, as shown in FIG. 6B, both surfaces of the cavity substrate 3 made of a silicon member are polished. And SC-1 cleaning (cleaning with a mixed solution of ammonia water and hydrogen peroxide solution) for cleaning fine particles such as particles adhering to the silicon member, suspended matters in the atmosphere, dust generation from the human body, and Combination cleaning of SC-2 cleaning (cleaning with a mixed solution of hydrochloric acid and hydrogen peroxide solution) for cleaning the metal adhering to the silicon member is performed. In this method, foreign substances are removed in advance so as not to obstruct the oxide film formation and to prevent the cavity substrate from taking in the metal adhering to the surface by the heat treatment during the film formation. Note that the cleaning method is not particularly limited to SC-1 cleaning or SC-2 cleaning as long as particles and metals can be removed.

After the cleaning, the surface to be the lower surface of the cavity substrate 3 is opposed to a solid diffusion source mainly composed of B ₂ O ₃ and set on a quartz board. Then, the quartz boat is set in a vertical furnace, the inside of the furnace is set to a nitrogen atmosphere, the temperature is raised to a predetermined temperature and held for a certain period of time, boron (boron) is diffused into the silicon substrate, the diaphragm 30 and the like A boron doped layer 30a is formed.

Next, a TEOS film 31a to be the insulating film 31 is formed on the surface of the boron doped layer 30a by plasma CVD. Here, before the TEOS film 31a is formed, an O ₂ plasma process is performed to clean the surface of the silicon member (boron doped layer 30a). Thereby, the uniformity of the withstand voltage of the TEOS film 31a is improved. Further, a portion facing the equipotential contact 25 at the time of anodic bonding is removed from the TEOS film 31a to form an insulating film window 38 exposing the silicon member, and the cavity substrate 3 and the electrode portions 22, 23 are formed through this portion. Can be in direct contact (see FIG. 9).

  At this time, even if the ITO that forms the equipotential contact 25 of the electrode substrate 2 and the TEOS film 31a that forms the insulating film 31 of the cavity substrate 3 are not formed to have exactly the same thickness, the sputtering is usually performed. The thickness error range may be within a range that occurs in the film formation by the method. Since a strong electric field is generated by anodic bonding, even if the equipotential contact 25 and the TEOS film 31a are not in contact with each other, an electrical connection is ensured between the electrode portions 22 and 23 and the silicon member so that the potential is equal. So that there is no particular problem.

  Next, as shown in FIG. 6C, after the cavity substrate 3 made of a silicon member and the electrode substrate 2 made of a glass member are heated to, for example, 360 ° C., the electrode substrate 2 is connected to the negative electrode side, After the cavity substrate 3 is connected to the positive electrode side, a voltage of 800 V is applied to perform anodic bonding between the cavity substrate 3 and the electrode substrate 2. This anodic bonding aligns the cavity substrate 3 and the electrode substrate 2. At this time, the equipotential contact 25 provided on each of the lead portions 23 of the electrode substrate 2 is positioned in the window 38 from which the insulating film 31 of the cavity substrate 3 is removed, and as shown in FIG. The equipotential contact 25 is fitted into the window 38 from which the insulating film 31 on the cavity substrate 3 side is removed. Thereafter, the two substrates 3 and 2 are sandwiched and pressed by a metal plate in contact with the cavity substrate 3 and a metal plate in contact with the electrode substrate 2 (not shown). A voltage of 800 V is applied by connecting a positive electrode to the metal plate in contact with the cavity substrate 3 and connecting a negative electrode to the metal plate in contact with the electrode substrate 3. In this way, the lead portions 23 of the individual electrodes 22 and the cavity substrate 3 come into contact with each other via the equipotential contact 25, so that the equipotential between the cavity substrate 3 and the electrode portions 22 and 23 is ensured.

  After anodic bonding in this manner, as shown in FIG. 7D, the cavity substrate 3 is polished and thinned by mechanical grinding. In addition, it is desirable to remove the work-affected layer generated on the surface of the cavity substrate 3 with a potassium hydroxide aqueous solution or the like after mechanical grinding.

  Then, as shown in FIG. 7E, a TEOS film (not shown) is formed on the surface of the cavity substrate 3 by plasma CVD, and then a resist is applied to the surface of the TEOS film to form a recess 32a that becomes the pressure chamber 32. Then, the shapes of the recess 33a to be the first hole 33 and the droplet supply recesses 70a and 70b to be the droplet supply hole 70 are patterned. Then, for example, the cavity substrate 3 is etched with an aqueous potassium hydroxide solution to form a recess 32 a that becomes the pressure chamber 32, a recess 33 a that becomes the first hole 33, and droplet supply holes 70 a and 70 b that become the droplet supply holes 70. Then, the TEOS film is peeled off. As described above, when the boron doped layer 30a is formed on the cavity substrate 3, the boron doped layer 30a remains.

  Next, as shown in FIG. 7F, the RIE (Reactive Ion Etching) or the like remains in the concave portion 33a that becomes the first hole portion 33 and the droplet supply holes 70a and 70b that become the droplet supply holes 70. The boron doped layer 30a is removed, and the first hole 33 and the droplet supply hole 70 are formed. By opening the IC mounting recess 21 in this way, the individual electrode 22 becomes electrically independent.

  Then, as shown in FIG. 8G, the gap 73 is sealed by the sealing member 71. For example, when a resin such as polyparaxylene is used as the material of the sealing member 71, the sealing member 71 can be formed by applying a sealing material at a predetermined position with a needle. When a metal material such as silicon oxide, aluminum oxide, silicon oxynitride, or silicon nitride is used as the material of the sealing member 71, the sealing member 71 can be formed by CVD using a mask made of silicon or the like, for example. .

  Next, as shown in FIG. 8 (h), the reservoir substrate 4 is bonded to the surface of the cavity substrate 3 on which the recesses 32 a to be the pressure chambers 32 are formed. At this time, as described above, the first hole portion 33 and the second hole portion 42 communicate with each other so that the accommodating portion 72 is formed. The reservoir substrate 4 is made of, for example, silicon, and has a concave portion 40a serving as a common droplet chamber 40 for supplying droplets to the pressure chamber 32 in advance, and a through hole 41 for transferring droplets from the common droplet chamber 40 to the pressure chamber 32. In addition, a nozzle communication hole 35 for transferring droplets from the pressure chamber 32 to the nozzle hole 43 and a second hole portion 42 are formed. The reservoir substrate 4 is formed by, for example, forming a silicon oxide film on a silicon member, patterning a resist on the surface of the silicon oxide film, etching a predetermined portion of the silicon oxide film, and then etching the silicon member with an aqueous potassium hydroxide solution or the like. It can be formed by etching.

  Then, as shown in FIG. 8 (i), a driver IC 60 is prepared and connected to the lead portions 23 of the individual electrodes 22 constituting two rows of electrode rows A and B in the first hole portion 33. IC 60 is mounted on electrode substrate 2. In the first embodiment, the driver IC 60 is mounted by attaching an anisotropic conductive ACF (Anisotropic Conductive Film) or ACP (Anisotropic Conductive Paste) to a connection terminal provided below the driver IC 60. Yes.

Then, as shown in FIG. 8J, the nozzle substrate 5 in which the nozzle holes 43 are formed by ICP discharge (Inductively Coupled Plasma) or etching is bonded to the reservoir substrate 4 using an adhesive or the like.
Finally, the bonded substrate to which the electrode substrate 2, the cavity substrate 3, the reservoir substrate 4, and the nozzle substrate 5 are bonded is diced to complete each droplet discharge head 1.

  According to the first embodiment, since the equipotential contact 25 is provided for each lead portion 23 of the individual electrode 22 provided on the electrode substrate 2, even when individually closed electrodes are wired in the head, during anodic bonding An equipotential can be ensured. Further, since the equipotential contact 25 is provided in the lead portion 23 of each individual electrode 22, it is not necessary to provide the equipotential contact 25 separately, and the head can be miniaturized. Further, in order to remove a part on the side of the cavity substrate 3 in the vicinity corresponding to the equipotential contact 25 so as to become a through hole after anodic bonding (see FIG. 7F), it is easy to make the individual electrodes 22 independent. It can be carried out.

Embodiment 2. FIG.
In the first embodiment, the equipotential contact 25 is formed on the lead portion 23 of each individual electrode 22 of the electrode substrate 2, but in the second embodiment, the equipotential contact 25 is on the cavity substrate 3 side facing the electrode substrate 2. However, it is provided at all positions corresponding to the lead portions 23 of the individual electrodes 22 (not shown).
That is, a post portion protruding toward the electrode substrate 2 is formed on the surface of the cavity substrate 3 facing the electrode substrate 2, and the post portion on the cavity substrate 3 side is the individual electrode 22 on the electrode substrate 2 side during anodic bonding. These are all in contact with all the lead parts 23 to form an equipotential.

That is, unlike the manufacturing process of FIG. 6A shown in the first embodiment, when the lead portion 23 of the individual electrode 22 is formed in the second recess 20b, the post 24 is provided in the second recess 20b. On the other hand, unlike the manufacturing process of FIG. 6B, for example, a post protruding toward the electrode substrate 2 is formed in a portion corresponding to the window 38 of the insulating film 31, and this post is individually connected at the time of anodic bonding. An equipotential is formed in contact with all of the lead portions 23 of the electrode 22. In this case, the post is formed, for example, by etching the cavity substrate 3. Further, it is necessary to remove the insulating film from the portion where the post of the cavity substrate 3 formed in this way contacts all the lead portions 23 of the individual electrodes 22 of the electrode substrate 2, that is, from the contact portion of the post. Become.
Other configurations and operations are substantially the same as those in the case of the first embodiment, and a description thereof will be omitted.

  According to the second embodiment, since the equipotential contact 25 is provided in a portion where the cavity substrate 3 corresponds to all the lead portions 23 of the individual electrodes 22 of the electrode substrate 2, individually closed electrodes are wired in the head. However, equipotentials can be ensured during anodic bonding. Further, since the equipotential contact 25 is provided on the cavity substrate 3 side, it is not necessary to provide the equipotential contact 25 separately, and the head can be miniaturized. Furthermore, since part of the cavity substrate 3 in the vicinity that becomes the equipotential contact 25 is removed so as to become a through hole after anodic bonding, the individual electrode 22 can be easily made independent.

Embodiment 3. FIG.
FIG. 10 is a perspective view illustrating an example of a droplet discharge apparatus equipped with the droplet discharge head according to the first and second embodiments. Note that the droplet discharge device 100 shown in FIG. 10 is a general inkjet printer.
The droplet discharge head 1 according to the first and second embodiments is small in size and excellent in discharge stability and durability, and is connected by a single FPC 35. Therefore, the droplet discharge device 100 is small in size and has printing performance and High durability.
In addition to the inkjet printer shown in FIG. 10, the droplet discharge head 1 according to the first and second embodiments can be used for variously changing droplets to manufacture a color filter for a liquid crystal display and a light emitting portion of an organic EL display device. The present invention can also be applied to the formation of liquid and the discharge of biological liquids.

1 is an exploded perspective view of a droplet discharge head according to Embodiment 1 of the present invention. FIG. 2 is a longitudinal sectional view showing a state in which the droplet discharge head shown in FIG. 1 is assembled. FIG. 3 is a plan view showing a main part of an electrode portion of the droplet discharge head shown in FIGS. 1 and 2. AA sectional drawing of FIG. BB sectional drawing of FIG. FIG. 3 is a longitudinal sectional view showing a manufacturing process of a droplet discharge head according to Embodiment 1 of the present invention. FIG. 7 is a longitudinal sectional view showing a step that follows the manufacturing step of FIG. 6. FIG. 8 is a longitudinal sectional view showing a step that follows the manufacturing step of FIG. 7. Explanatory drawing which shows the joining state of the electrode substrate and cavity board | substrate at the time of anodic bonding. FIG. 3 is a perspective view showing a droplet discharge device on which any one of the droplet discharge heads of Embodiment 1 and Embodiment 2 is mounted.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Droplet discharge head, 2 Electrode substrate (2nd substrate), 3 Cavity substrate (1st substrate), 4 Reservoir substrate, 5 Nozzle substrate, 20, 20a, 20b Recess (electrode groove), 22 Individual electrode, 23 Individual electrode lead part, 24 post, 25 equipotential contact, 30 diaphragm, 31 insulating film, 38 window from which the insulating film has been removed, 60 driver IC, 72 accommodating part, 73 gap, 100 droplet discharge device.

Claims (3)

A first substrate having a diaphragm, and a second substrate in which an electrode groove is formed, and an individual electrode that is opposed to the diaphragm with a gap is provided in the electrode groove; In the electrostatic actuator formed by anodically bonding the second substrate,
As equipotential contacts for electrically connecting the said first substrate and the second individual electrodes formed on the second substrate during anodic bonding of the substrate and the first substrate,
The electrode groove side wall protrudes toward the center of the electrode groove to form a run-up portion, and the ride-up portion has a configuration in which a part of the lead portion of the individual electrode is run up,
An electrostatic actuator characterized in that a portion of each lead portion of each individual electrode that has ridden on the climbing portion is brought into direct contact with the first substrate . An electrostatic actuator according to claim 1,
The first substrate has a recess whose bottom wall forms the diaphragm and serves as a discharge chamber for retaining the droplets;
A nozzle substrate having a plurality of nozzle holes for discharging droplets;
A recess serving as a common droplet chamber for supplying droplets to the discharge chamber, a through-hole for transferring droplets from the common droplet chamber to the discharge chamber, and transferring droplets from the discharge chamber to the nozzle holes A reservoir substrate having nozzle communication holes;
An IC driver for supplying a drive signal to the individual electrodes,
A droplet discharge head, wherein the second substrate, the first substrate, the reservoir substrate, and the nozzle substrate are stacked. A droplet discharge apparatus, comprising the droplet discharge head according to claim 2.

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