JP2010137486A - Electrostatic actuator, liquid droplet discharge head, liquid droplet discharge apparatus, and electrostatic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an electrostatic actuator or the like, wherein the manufacturing process and configuration thereof are simplified and removal of residual charges, and so on can be achieved. <P>SOLUTION: The electrostatic actuator includes: individual electrode parts 12A for an electrode 12 serving as a fixed electrode formed on an electrode substrate 10; a vibrating plate 22 serving as a movable electrode that is opposed to the individual electrode parts 12A with a predetermined distance between them and operated by electrostatic force generated between individual electrode parts 12A; an insulation film 13 covering each individual electrode part 12A; and surface protective film 23 directly disposed on a face of the vibrating plate 22, which face is opposed to the individual electrode parts 12A, used to protect the insulation film 13 from friction due to contact, and made of a carbon material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

According to the present invention, in the microfabricated element, the movable part is displaced by the applied force, and the operation (drive)
The present invention relates to an electrostatic actuator that performs the above, an electrostatic drive device such as a droplet discharge head, and the like.

For example, microfabrication technology (MEMS: Micro) that forms fine elements by processing silicon, etc.
Electro Mechanical Systems) has made rapid progress. Examples of microfabricated elements formed by microfabrication technology include droplet ejection heads (inkjet heads), micropumps, and variable optical filters used in recording (printing) devices such as droplet ejection printers. And electrostatic actuators such as motors.

Here, a liquid droplet ejection head using an electrostatic actuator (electro-mechanical energy conversion element) will be described as an example of a microfabricated element. A droplet discharge type recording (printing) apparatus is used for printing in various fields regardless of whether it is for home use or industrial use. What is the droplet discharge method?
For example, a liquid droplet ejection head having a plurality of nozzles is moved relative to an object, and liquid droplets are ejected to a predetermined position of the object to perform recording such as printing. This method uses liquid crystal (Liquid
It is also used in the manufacture of microarrays of biomolecules such as color filters, display panels (OLED) using electroluminescent elements such as organic compounds, DNA, proteins, etc. ing.

The droplet discharge head includes a plurality of discharge chambers for storing liquid in a part of the flow path, and is a wall on at least one surface of the discharge chamber (here, a bottom wall, hereinafter referred to as a diaphragm). There is a method in which the pressure in the discharge chamber is increased by changing the shape and the droplets are discharged from each communicating nozzle. When an electrostatic actuator is used for a droplet discharge head, as a force (energy) for displacing a diaphragm, which is a movable part, for example, a diaphragm is used as a movable electrode, and a fixed distance is set to face the diaphragm separately from each other. An electrostatic force (in particular, electrostatic attraction is used here, hereinafter referred to as electrostatic force) generated between the electrodes (hereinafter referred to as individual electrodes) is used.

Then, for example, by supplying electric charges as instructed by a control means that performs drive control, a potential difference is generated between the diaphragm and the individual electrodes, an electrostatic force is generated, and the diaphragm is attracted to the individual electrodes to be displaced and brought into contact with each other. . After that, when the electrostatic force is weakened or stopped, the shape of the discharge chamber (
Since the restoring force (elastic force) at which the displaced diaphragm) returns to its original state and becomes in an equilibrium state becomes larger, the diaphragm is displaced away from the individual electrode and returned to its original position. By repeating these, the diaphragm is driven to be displaced.

Here, in order to prevent a dielectric breakdown or a short circuit between the diaphragm and the individual electrode and maintain an electrostatic force, an insulating film is generally formed on a surface where the diaphragm and the individual electrode face each other. However, at this time, there may be a phenomenon in which charges remain in the insulating film by repeating contact by contact.
If charges remain in the insulating film, an electrostatic force is always generated between the individual electrode and the diaphragm without charge supply based on external control. As a result, speed reduction or the like occurs, and driving characteristics change. In some cases, the diaphragm may stick. Therefore, an electrostatic actuator that prevents the residual of charges by laminating two types of films, a protective film with a high volume resistivity and a protective film with a low volume resistivity, on the surface of the individual electrode, and transferring the charge from the protective film with a low resistance to the conductive material. (For example, refer to Patent Document 1).
JP 2002-46282 A

However, the electrostatic actuator as described above forms a diaphragm with a metal such as molybdenum, tungsten, or nickel. Further, in order to form a protective film having a low volume resistivity, a treatment such as doping with phosphorus, boron or the like may be performed. This complicates the configuration of the electrostatic actuator and may complicate the manufacturing process.

Accordingly, an object of the present invention is to obtain an electrostatic actuator or the like that can simplify the manufacturing process and configuration and can remove residual charges and the like in order to solve such problems.

Therefore, an electrostatic actuator according to the present invention includes a fixed electrode formed on a substrate, a movable electrode that is opposed to the fixed electrode at a predetermined distance and that is operated by electrostatic force generated between the fixed electrode, and the fixed electrode. And a surface protection film made of a carbon-based material that is provided directly on the surface of the movable electrode facing the fixed electrode and protects the insulation film from abrasion due to contact.
According to the present invention, the fixed electrode is covered with the insulating film, and after the movable electrode and the fixed electrode are insulated, the surface protection film is directly provided on the movable electrode, thereby stopping the supply of charge and the like. Even if it is detached, the charge remaining in the insulating film is moved to the surface protective film and the movable electrode at the time of contact and released, so that no charge remains in the insulating film. Drive characteristics can be maintained. And since it implement | achieves by attaching | subjecting a surface protective film directly to the movable electrode side, a structure and manufacture can be simplified. In addition, for example, by providing a surface protective film with high surface smoothness and a low coefficient of friction, the insulating film can be protected from abrasion due to contact with the movable electrode, such as contact, maintaining durability and long life The electrostatic actuator can be obtained.

The surface protective film of the electrostatic actuator according to the present invention is made of diamond or diamond-like carbon.
According to the present invention, since the surface protective film is composed of hard diamond or diamond-like carbon, it is possible to increase the natural frequency and increase the driving frequency by increasing the restoring force due to the elasticity of the movable electrode. , Power saving and high speed can be achieved. Also,
Since the restoring force is increased, sticking can be prevented.

The volume resistivity of the surface protective film of the electrostatic actuator according to the present invention is 10 ⁹ to 10.
¹² orders.
According to the present invention, since the volume resistivity of the surface protective film is on the order of 10 ⁹ to 10 ¹² , the electric resistance in the surface protective film is lowered, and the electric charge remaining in the insulating film is not moved and left. In this way, the driving characteristics can be maintained.

In the electrostatic actuator according to the present invention, a surface protective film having a volume resistivity of the order of 10 ¹² or more is further provided on the insulating film covering the fixed electrode.
According to the present invention, since the surface protective film having a volume resistivity of the order of 10 ¹² or more is provided on the insulating film, the surface protective film on the individual electrode side maintains the insulating property while maintaining the surface on the movable electrode side. By making contact with the protective film between the surface protective films, the insulating film can be protected without contacting the movable electrode or the like.

In addition, a droplet discharge head according to the present invention includes the electrostatic actuator described above, and uses at least a part of a discharge chamber filled with a liquid as a movable electrode, and drops from a nozzle communicating with the discharge chamber by displacement of the movable electrode. To discharge.
According to the present invention, since the electrostatic actuator is used as a liquid pressurizing unit of the droplet discharge head, it is possible to prevent charge residue and maintain discharge characteristics, and when contact or the like is repeated Can be prevented, and durability can be maintained, and a long-life droplet discharge head can be obtained.

A droplet discharge device according to the present invention is equipped with the above-described droplet discharge head.
According to the present invention, since the above-described droplet discharge head is mounted, a long-life droplet discharge device can be obtained.

Moreover, the electrostatic drive device according to the present invention includes the above-described electrostatic actuator.
According to the present invention, since the above electrostatic actuator is mounted on an electrostatic drive device, the drive characteristics can be maintained while preventing residual charge, and sticking when contact or the like is repeated can be maintained. It is possible to prevent, maintain durability, and obtain a long-life electrostatic drive device.

Embodiment 1 FIG.
FIG. 1 is an exploded view of a droplet discharge head according to Embodiment 1 of the present invention. FIG. 1 shows a part of a droplet discharge head. In this embodiment, for example, a face eject type liquid droplet ejection head will be described as a representative of an element (device) using an electrostatic actuator driven by an electrostatic method. (In addition, in order to make the components shown and easy to see, the relationship between the sizes of the components in the following drawings including FIG. 1 may be different from the actual ones.
The upper side of the figure is the upper side and the lower side is the lower side). Further, specific numerical values for thickness, depth, and the like are examples.

As shown in FIG. 1, the droplet discharge head according to the present embodiment is configured by laminating an electrode substrate 10, a cavity substrate 20, and a nozzle substrate 30 in order from the bottom. Generally, the electrode substrate 10 and the cavity substrate 20 are bonded by anodic bonding. Cavity substrate 2
0 and the nozzle substrate 30 are joined using an adhesive such as an epoxy resin.

The electrode substrate 10 is mainly made of a substrate such as a borosilicate heat-resistant hard glass having a thickness of about 1 mm. In the present embodiment, the glass substrate is used, but single crystal silicon may be used as the substrate, for example. On the surface of the electrode substrate 10, a discharge chamber 21 of a cavity substrate 20 to be described later is provided.
A plurality of recesses 11 are formed in accordance with the recesses. In addition, an individual electrode portion 12A, a lead wiring portion 12B, and a terminal portion 12C (hereinafter referred to as the electrode 12 when they are not particularly required to be distinguished) are provided inside the recess 11 (particularly the bottom portion). . Between the diaphragm 22 and the individual electrode portion 12 </ b> A, a certain gap (gap) that allows the diaphragm 22 to bend (displace) is formed by the recess 11. The electrode 12 is formed by forming a film of ITO with a thickness of about 0.1 μm inside the recess 11 by sputtering, for example. Furthermore, in the present embodiment, the diaphragm 22 and the individual electrode portion 12A are electrically insulated,
An insulating film 13 for protecting the individual electrode portion 12A is formed, for example, about 0.09 μm (90 nm) so as to cover at least the individual electrode portion 12A. The material of the insulating film 13 is not particularly limited. For example, silicon oxide (SiO ₂ ) or silicon nitride (SiN) can be used as the material. In this embodiment, a TEOS film using a plasma CVD (also referred to as TEOS-pCVD) method (in this case, a SiO ₂ film formed using tetraethyl orthosilicate (ethyl silicate) as a source gas) is used. It will be described as being used. By using TEOS as a source gas, a denser film can be formed as compared with the case where a film is formed using another material. In addition, the electrode substrate 10 is provided with a through hole serving as a liquid supply port 14 serving as a flow path for taking in liquid supplied from an external tank (not shown).

The cavity substrate 20 is mainly made of, for example, a silicon single crystal substrate (hereinafter referred to as a silicon substrate) having a (110) plane orientation on the surface. The cavity substrate 20 is formed with a recess that becomes a discharge chamber 21 for temporarily storing a liquid to be discharged (a bottom wall is a vibration plate 22 that becomes a movable electrode) and a recess that becomes a reservoir 24. External power supply means (
For example, a common electrode terminal 27 serving as a terminal for supplying a charge having a polarity opposite to that of the charge supplied to the electrode 12 is provided from a not-shown substrate to the substrate (vibrating plate 22).

Further, in the present embodiment, the surface for preventing the insulating film 13 from being damaged by the contact with the vibration plate 22 on the portion (the vibration plate 22 portion) facing the fixed electrode portion 12A on the lower surface of the cavity substrate 20. A protective film 23 is provided. The surface protective film 23 is made of a hard carbon-based material such as diamond or diamond-like carbon (hereinafter referred to as DLC) that has high adhesion to silicon, high surface smoothness, and low friction. Shall be used. Here, DLC can be made to have different physical characteristics by containing hydrogen or the like. Therefore, the surface protective film 23 of the present embodiment has a volume resistivity of 1 × 10 ⁹ to 1 × 1.
It is assumed that DLC which is 0 ¹² (Ω · cm) (on the order of 10 ⁹ to 10 ¹² ) is used as a material. As a result, the electric charge remaining on the insulating film 13 at the time of contact with the insulating film 13 due to contact moves to the surface protective film 23 and further moves to the vibration plate 22 (cavity substrate 20) serving as a movable electrode. Do not leave a charge on

The nozzle substrate 30 is also mainly made of a silicon substrate, for example. Nozzle substrate 30
A plurality of nozzles 31 are formed. Each nozzle 31 discharges liquid pressurized by driving the diaphragm 22 to the outside as droplets. If the nozzles 31 are formed in a plurality of stages, an improvement in straightness when ejecting liquid droplets can be expected. Therefore, in this embodiment, the nozzles 31 are formed in two stages. In the present embodiment, a diaphragm 32 is further provided to buffer the pressure applied in the direction of the reservoir 24 as the diaphragm 22 is bent. In addition, an orifice 33 serving as a groove for communicating the discharge chamber 21 and the reservoir 24 is provided.

FIG. 2 is a diagram illustrating a part of a cross section of the droplet discharge head according to the first embodiment. 2A is a view as seen from the direction in which the nozzles 31 are arranged in the droplet discharge head (the short direction in the discharge chamber 21), and FIG. 2B is orthogonal to the direction in which the nozzles 31 are arranged. Direction (Discharge chamber 21
It is the figure seen from (longitudinal direction in).

In FIG. 2, the discharge chamber 21 stores liquid to be discharged from the nozzle 31. Discharge chamber 21
The pressure in the discharge chamber 21 is increased by bending the diaphragm 22 which is the bottom wall of the nozzle 31.
A droplet is discharged from the nozzle. Here, in this embodiment, it is assumed that the diaphragm 22 is configured by forming a high-concentration boron-doped layer on the silicon substrate that can be used as a movable electrode and is convenient for the etching process. In addition, a sealing material 25 is provided at the electrode outlet 26 in order to block the gap from outside air and seal it so that foreign matter, moisture (water vapor) and the like do not enter the gap.

For example, an oscillation drive circuit 41 such as a driver IC has an FPC (Flexible Print Circuit),
It is electrically connected to the terminal portion 12C and the common electrode terminal 27 through a wiring 42 such as a wire, and controls supply and stop of electric charge (electric power) to the electrode 12 and the cavity substrate 20 (vibrating plate 22).
The oscillation drive circuit 41 oscillates at a predetermined frequency, for example, and supplies a charge by applying, for example, a pulse potential to the electrode 12. When the oscillation drive circuit 41 is driven to oscillate, when an electric charge is supplied to the individual electrode portion 12A to be positively charged and the diaphragm 22 is relatively negatively charged, it is attracted to the individual electrode portion 12A by electrostatic force. Bend. This increases the volume of the discharge chamber 21. When the supply of electric charge is stopped, the diaphragm 22 returns to its original state, but the volume of the discharge chamber 21 at that time also returns to its original state, and a differential droplet is discharged by the pressure. Recording such as printing is performed when the droplets land on a recording sheet to be recorded, for example.

In the present embodiment, the individual electrode portion 12A is covered with the insulating film 13, and the diaphragm 22 and the individual electrode portion 1 are covered.
Insulation with 2A is ensured by the insulating film 13 alone. In addition, the individual electrode portion 12A of the diaphragm 22
A surface protective film 23 is provided in a portion opposite to the insulating film 13 to prevent the insulating film 13 from being worn by contact with the diaphragm 22 and to ensure long-term insulation and durability. Furthermore, in the surface protective film 23 of the present embodiment, the charge remaining in the insulating film 13 at the time of contact is moved so as not to leave charge in the insulating film 13. Therefore, the surface protective film 23 is directly provided on the cavity substrate 20 without forming an insulating film. The surface protective film 23 has conductivity sufficient to move the charge remaining in the insulating film 13. Therefore, in this embodiment, DLC having a volume resistivity on the order of 10 ⁹ to 10 ¹² (Ω · cm) is used. DLC has a large film stress, and adhesion is a problem depending on the underlying material, but silicon has good adhesion. Therefore, even if distortion occurs in accordance with the deformed diaphragm 22, there is no fear of peeling in the gap, and reliability can be maintained.

FIG. 3 is a diagram illustrating a manufacturing process of the droplet discharge head according to the first embodiment. A manufacturing process of the droplet discharge head will be described with reference to FIG. In practice, a plurality of droplet discharge head members are simultaneously formed for each wafer, but only a part of them is shown in FIG.

One side of the silicon substrate 51 (on the side of the bonding surface with the electrode substrate 10) is mirror-polished, for example 2
A substrate having a thickness of 20 μm (to be the cavity substrate 20) is produced (FIG. 3A). Next, the surface of the silicon substrate 51 on which the boron doped layer 52 is to be formed is opposed to a solid diffusion source mainly composed of B ₂ O ₃ , and boron is diffused into the silicon substrate 51 by being placed in a vertical furnace. Layer 52 is formed.

Then, D is directly applied to the surface on which the boron doped layer 52 is formed by plasma CVD.
An LC film is formed with a desired thickness. Then, patterning is performed so that a portion corresponding to the vibration plate 22 remains, and an unnecessary DLC film is removed by, for example, O ₂ ashing to form a surface protective film 23 (FIG. 3B).

The electrode substrate 10 is produced in a separate process from the above (a) and (b). A recess 11 having a depth of about 0.3 μm is formed on one surface of a glass substrate of about 1 mm. After the formation of the recess 11, for example, an electrode 12 having a thickness of, for example, 0.1 μm is simultaneously formed by using, for example, a sputtering method. Finally, a hole to be the liquid intake 14 is formed by sandblasting or cutting. Thereby, the electrode substrate 10 is produced. Then, the silicon substrate 51 and the electrode substrate 10
After heating to a predetermined temperature, the negative electrode is connected to the electrode substrate 10 and the positive electrode is connected to the silicon substrate 51,
Anodic bonding is performed by applying a voltage.

For example, the thickness of the silicon substrate 51 is reduced to about 50 μm by grinding the surface of the silicon substrate 51 and anisotropic wet etching (hereinafter referred to as wet etching) on the substrate after anodic bonding (hereinafter referred to as a bonded substrate) ( FIG. 3 (c)).

A silicon oxide hard mask (hereinafter referred to as TEOS hard mask) 53 by TEOS is formed on the surface of the bonding substrate subjected to wet etching by plasma CVD, for example, about 1.5 μm. Further, the TEOS in the portion that becomes the discharge chamber 21 and the electrode outlet 26.
In order to wet-etch the hard mask 53, resist patterning is performed. Then, these portions are wet-etched using a hydrofluoric acid aqueous solution until the TEOS hard mask 53 disappears, and the TEOS hard mask 53 is patterned to expose the silicon substrate 51. As for the portion to be the reservoir 24, a TEOS hard mask 53 is left slightly in order to leave a thickness at the bottom of the reservoir 24. Further, for example, a portion of the electrode extraction opening 26 that has a large area and is easily broken may be left with a slight thickness of resist so as to prevent cracking in a later step. Then, after the wet etching, the resist is peeled off (FIG. 3D).

Next, the bonding substrate is dipped in a 35 wt% potassium hydroxide aqueous solution, and wet etching is performed until the thickness of the portion that becomes the discharge chamber 21 and the electrode outlet 26 becomes about 10 μm. Further, the bonded substrate is immersed in a 3 wt% potassium hydroxide aqueous solution, and the boron doped layer 52 is exposed, and wet etching is continued until it is determined that an etching stop at which the progress of etching is extremely slow has been effective (FIG. 3). (E)).

When the wet etching is completed, the bonding substrate is immersed in a hydrofluoric acid aqueous solution, and the silicon substrate 51
The TEOS hard mask 53 on the surface is peeled off. Next, in order to remove the boron dope layer 52 in the portion serving as the electrode outlet 26, a silicon mask having an opening in the portion serving as the electrode outlet 26 is attached to the surface of the bonding substrate on the silicon substrate 51 side.

Then, RIE dry etching (anisotropic dry etching) is performed for 30 minutes, and plasma is applied only to a portion that becomes the electrode outlet 26 to open. Here, for example, in order to increase the alignment accuracy between the bonding substrate and the mask, the silicon mask may be mounted by pin alignment in which pins are passed between the bonding substrate and the silicon mask. Here, the openings are formed by anisotropic dry etching, but the boron doped layer 52 may be broken by protruding with pins or the like. Then, the sealing material 25 is used to seal the gap portion from the outside air (FIG. 3F). The material, sealing method, and the like of the sealing material 25 are not particularly limited. For example, the sealing material 25 is formed by applying an epoxy resin or depositing silicon oxide on the opening of the electrode outlet 26.

When the sealing is completed, for example, a mask having an opening in a portion that becomes the common electrode terminal 27 is used.
The common electrode terminal 27 is formed by attaching to the surface of the bonding substrate on the silicon substrate 51 side and performing sputtering or the like using platinum (Pt) as a target, for example. And the nozzle board | substrate 30 produced by the separate process previously is adhere | attached and bonded from the cavity board | substrate 20 side of a joining board | substrate, for example with an epoxy-type adhesive agent (FIG.3 (g)). Then, dicing is performed along the dicing line, and cutting into individual droplet discharge heads is completed. Further, connection to an oscillation drive circuit 41 such as an IC driver is performed via a wiring 42.

As described above, in the droplet discharge head that is the electrostatic actuator of the first embodiment, the insulating film 13 is provided on the individual electrode portion 12A serving as the fixed electrode, and the surface protection is directly applied to the diaphragm 22 serving as the movable electrode. A film 23 is provided, and the charge remaining in the insulating film 13 is normally moved to the surface protective film 23 and the vibration plate 22 (cavity substrate 20) at the time of contact so as to be released even when the charge supply is stopped. Therefore, the charge of the insulating film 13 can be removed. Thereby, generation of unnecessary electrostatic force due to accumulation of residual charges or the like can be prevented, and discharge characteristics can be maintained. Since the residual charge in the insulating film 13 is removed by directly attaching the surface protective film 23 to the diaphragm 22, for example, in order to remove the residual charge, a plurality of films are formed on the individual electrodes. The surface protective film 23 having high surface smoothness and serving as a protective film for the insulating film 13 at the time of contact can be used. The surface protective film 23 can protect the insulating film 13 from abrasion due to contact such as contact, and durability can be maintained and a long-life electrostatic actuator can be obtained.

Further, since the surface protective film 23 is made of DLC, the power can be saved and the speed can be increased by increasing the natural frequency by increasing the restoring force by the elasticity of the diaphragm 22. Can do. Further, since the restoring force is increased, sticking can be prevented. By making the volume resistivity of the surface protective film 23 on the order of 10 ⁹ to 10 ¹² , the electric resistance can be lowered and the charge remaining in the insulating film 13 can be moved.

Embodiment 2. FIG.
FIG. 4 is a diagram showing a part of a cross section of the droplet discharge head according to the second embodiment. 4A is a view as seen from the direction in which the nozzles 31 are arranged in the droplet discharge head (short direction in the discharge chamber 21), and FIG. 4B is orthogonal to the direction in which the nozzles 31 are arranged. Direction (Discharge chamber 21
It is the figure seen from (longitudinal direction in). In FIG. 4, the means, membranes, etc., having the same numbers as those in FIGS. 1 and 2 have the same role.

Similar to the surface protective film 23, the surface protective film 15 provided on the insulating film 13 is a film for protecting the insulating film 13. The surface protective film 15 in the present embodiment uses DLC as a material, like the surface protective film 23. By making the same kind of material having low friction properties contact, further long-term durability is ensured. Here, if the surface protective film 15 and the surface protective film 23 are both conductive, the diaphragm 22 and the individual electrode part 12 are short-circuited and stuck, resulting in functional failure. For this reason, the surface protective film 15 of the present embodiment uses DLC having a volume resistivity of 1 × 10 ¹² or more (Ω · cm) (on the order of 10 ¹² or more) in order to ensure insulation. Accordingly, the charge remaining on the surface protective film 15 moves to the surface protective film 23.

As described above, in the droplet discharge head according to the second embodiment, since the surface protective film 15 made of DLC is provided on the insulating film 13, wear is prevented without contacting the insulating film 13. be able to. Wear and the like can be further prevented by contacting the same material. Since the DLC having the volume resistivity of the surface protective film 15 of 10 ¹² or more (Ω · cm) is used, a short circuit between the electrodes at the time of contact can be prevented.

Embodiment 3 FIG.
In the above-described embodiment, the face eject type droplet discharge head has been described.
For example, the present invention can be applied to an edge eject type droplet discharge head that discharges droplets from the side. In addition, the three-layer droplet discharge head of the electrode substrate 10, the cavity substrate 20, and the nozzle substrate 30 has been described. For example, a four-layer structure liquid that is formed by newly stacking substrates with independent reservoir portions. The present invention can also be applied to a droplet discharge head.

Embodiment 4 FIG.
FIG. 5 is an external view of a droplet discharge apparatus using the droplet discharge head manufactured in the above embodiment. FIG. 6 is a diagram illustrating an example of main components of the droplet discharge device. 5 and 6 is intended for printing by a droplet discharge method (inkjet method). Further, it is a so-called serial type device. In FIG. 8, a drum 101 that supports a printing paper 100 that is a substrate to be printed and a droplet discharge head 102 that discharges ink to the printing paper 100 and performs recording are mainly configured. Although not shown, there is an ink supply means for supplying ink to the droplet discharge head 102. The print paper 110 is pressed and held on the drum 101 by a paper press roller 103 provided parallel to the axial direction of the drum 101. A feed screw 104 is provided parallel to the axial direction of the drum 101, and the droplet discharge head 102 is held. As the feed screw 104 rotates, the droplet discharge head 102 moves in the axial direction of the drum 101.

On the other hand, the drum 101 is rotationally driven by a motor 106 via a belt 105 or the like. The print control unit 107 also feeds the feed screw 104 based on the print data and the control signal.
The motor 106 is driven, and although not shown here, the oscillation driving circuit is driven to vibrate the vibration plate 22 to perform printing on the print paper 110 while performing control.

Here, the liquid is ejected onto the print paper 110 as ink, but the liquid ejected from the droplet ejection head is not limited to ink. For example, in applications that are discharged onto a substrate that will be a color filter, liquids that contain a pigment for a color filter, liquids that contain a compound that will be a light emitting element in applications that are discharged onto a display substrate such as an OLED, In this case, for example, a liquid containing a conductive metal may be discharged from a droplet discharge head provided in each device. In addition, in the case where the droplet discharge head is used as a dispenser and is used for discharging onto a substrate that is a microarray of biomolecules, DNA (De
oxyribo Nucleic Acids: other nucleic acids (eg Ribo Nucleic Acid)
: Ribonucleic acid, Peptide Nucleic Acids: Peptide nucleic acid, etc.) A liquid containing a probe such as a protein may be discharged. In addition, it can also be used for discharging dyes such as cloth.

Embodiment 5 FIG.
FIG. 7 is a diagram showing a wavelength tunable optical filter using the present invention. The above embodiment is
Although the liquid droplet ejection head has been described as an example, the present invention is not limited to the liquid droplet ejection head, and can be applied to an electrostatic driving device using an electrostatic actuator by other fine processing. For example, the wavelength tunable optical filter shown in FIG. 7 uses the principle of a Fabry-Perot interferometer and outputs light of a selected wavelength while changing the distance between the movable mirror 120 and the fixed mirror 121. In order to displace the movable mirror 120, the movable body 122 made of silicon and provided with the movable mirror 120 is displaced. Therefore, the fixed electrode 123 and the movable body 12
2 (movable mirror 120) are arranged to face each other at a predetermined interval (gap). At this time, the fixed electrode 1
An insulating film 124 is formed on 23, and a surface protective film 125 is formed on the movable body 122.

Similarly, the above-mentioned sealing portion is formed on other types of micro-fabricated actuators such as motors, sensors, SAW filters, resonator elements, wavelength tunable optical filters, mirror devices, and pressure sensors. Etc. can be applied.

2 is an exploded view of a droplet discharge head according to Embodiment 1. FIG. It is a figure showing a part of cross section of a droplet discharge head. It is a figure showing the manufacturing process of a droplet discharge head. 6 is a diagram illustrating a part of a cross section of a droplet discharge head according to Embodiment 2. FIG. It is an external view of a droplet discharge device using a droplet discharge head. It is a figure showing an example of the main structural means of a droplet discharge apparatus. It is a figure showing the wavelength tunable optical filter using this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electrode board | substrate, 11 Recessed part, 12 Electrode, 12A Individual electrode part, 12B Lead wiring part, 12C Terminal part, 13 Insulating film, 14 Liquid supply port, 15 Surface protective film, 20 Cavity board, 21 Discharge chamber, 22 Vibration plate 23 Surface protective film 24 Reservoir 2
5 Sealing material, 26 Electrode outlet, 27 Common electrode terminal, 30 Nozzle substrate, 31 Nozzle, 32 Diaphragm, 33 Orifice, 41 Oscillation drive circuit, 42 Wiring, 51
Silicon substrate, 52 boron doped layer, 53 TEOS hard mask, 100 printer, 101 drum, 102 droplet discharge head, 103 paper pressure roller, 104 feed screw, 105 belt, 106 motor, 107 print control means, 110 print paper, 120 movable Mirror, 121 Fixed mirror, 122 Movable body, 123 Fixed electrode, 124
Insulating film, 125 Surface protective film.

Claims (7)

A fixed electrode formed on the substrate;
A movable electrode facing the fixed electrode at a predetermined distance and operated by electrostatic force generated between the fixed electrode;
An insulating film covering the fixed electrode;
An electrostatic actuator comprising: a surface protective film made of a carbon-based material that is provided directly on a surface of the movable electrode facing the fixed electrode and protects the insulating film from abrasion due to contact. The electrostatic actuator according to claim 1, wherein the surface protective film is made of diamond or diamond-like carbon. The electrostatic actuator according to claim 1, wherein the surface resistivity of the surface protective film is on the order of 10 ⁹ to 10 ¹² . The electrostatic actuator according to claim 1, further comprising a surface protective film having a volume resistivity on the order of 10 ¹² or more on the insulating film covering the fixed electrode. It has the electrostatic actuator in any one of Claims 1-4,
A droplet discharge head, wherein at least a part of a discharge chamber filled with a liquid is used as the movable electrode, and droplets are discharged from a nozzle communicating with the discharge chamber by displacement of the movable electrode.   6. A droplet discharge apparatus comprising the droplet discharge head according to claim 5. An electrostatic device comprising the electrostatic actuator according to claim 1.

Images