JP2000025224A - Liquid ejector and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small liquid ejector excellent in mass productivity, and a manufacturing method thereof, in which liquid in a liquid channel can be driven efficiently using a thin film forming technology. SOLUTION: A plurality of liquid channels 12 are formed in a single crystal silicon substrate 1 while being partitioned by side walls 11. A filler 13 filling the liquid channel is thermally solidified and a thin film 15 is deposited. The filler 13 is in flush with the upper part of each side wall 11 and projecting downward between respective side walls 11, and the thin film 15 has similar shape. Subsequently, the filler 13 is removed thus forming the plurality of liquid channels 12 and the thin film 15 serving as a cover. Thereafter, an electrodes is formed on the thin film 15 and when a driving voltage is applied to the electrodes, liquid in each liquid channel 12 is pressurized and ejected from an opening made at one end thereof. According to the method, a small high density liquid ejector having high deformation amount and high driving efficiency can be manufactured easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a liquid discharge apparatus such as an ink jet head for discharging a liquid in a liquid flow path from a discharge port by pressurizing a liquid in a liquid flow path and a method of manufacturing the liquid discharge apparatus. .

[0002]

2. Description of the Related Art Conventionally, the above-described liquid ejecting apparatus represented by an ink-jet head has a very small size and high precision for the purpose of arranging a large number of nozzles at a high density corresponding to, for example, high-resolution printing. There is a need for a liquid ejection device. In addition, a manufacturing method which is excellent in mass productivity and capable of manufacturing these liquid ejecting apparatuses by a simple manufacturing process by performing fine processing is also required.

For example, in the case of manufacturing an ink jet head, another substrate serving as a cover member is joined to an upper portion of a substrate having a plurality of ink channels formed in a groove shape, and the other substrate is pressed by a pressing means. By forming an electrode or the like so as to function as an ink jet head, an integrated inkjet head can be manufactured.

[0004]

However, when an ink jet head as a liquid ejecting apparatus is manufactured by the above-mentioned conventional method, there are many problems. That is,
Since the cover member joined to the upper part of the substrate also serves as a movable part, it is desirable to use a thin film formed by using a thin film forming technique in order to obtain good driving efficiency. However, in order to form a groove-like liquid flow path as described above, it is necessary to have a structure in which a plurality of side walls are arranged in a girder shape, and a thin film must be formed on the upper part of each of these side walls. It cannot be easily manufactured. Moreover, it is more difficult to realize a structure in which the thin film can be directly moved as the pressing means. on the other hand,
If the cover member is formed by bonding using an adhesive or anodic bonding, it takes time and effort for positioning and bonding, and it is difficult to form a thin structure. Further, in the conventional method, it is difficult to sufficiently increase the deformation amount when the cover member is used as the movable portion in correspondence with the fine ink flow path.

As described above, in the conventional technique, the liquid in the liquid flow path is pressurized with a sufficient amount of deformation by driving at a low voltage, and a thin film is formed uniformly on a large number of side walls having a complicated structure. It has been difficult to manufacture a liquid discharge apparatus which is excellent in mass productivity and suitable for miniaturization.

In view of the above, the present invention has been made in view of the above-mentioned problem, and a thin film functioning as a pressurizing means is deposited on a substrate having a liquid flow path formed thereon by using a thin film forming technique, thereby achieving low voltage driving. Can pressurize the liquid by a large amount of deformation,
An object of the present invention is to provide a liquid ejecting apparatus which is excellent in mass productivity and suitable for miniaturization, and a method for manufacturing the liquid ejecting apparatus.

[0007]

According to a first aspect of the present invention, there is provided a liquid ejecting apparatus, wherein a plurality of liquid passages are formed in a groove shape and are partitioned by a side wall and have at least one end with an ejection port. Substrate, as a cover covering the entirety of the plurality of liquid flow paths, a thin film deposited on the upper end of each of the side walls, and deforming the thin film to pressurize the liquid in each of the liquid flow paths, Pressurizing means for discharging a liquid from a discharge port, wherein the thin film is entirely in the plurality of liquid flow paths,
A liquid ejecting apparatus characterized in that the liquid ejecting apparatus is formed so as to have an upwardly convex shape between adjacent side walls from the height of the upper end of each side wall.

According to the present invention, a plurality of liquid flow paths are formed on the substrate by the side walls and formed in a groove shape, and as a cover member for the entire inside of the liquid flow paths, each side wall is adjacent at the height of the upper end. A thin film having an upwardly convex cross-sectional shape is deposited between the side walls, and furthermore, a pressurizing means for deforming the thin film to pressurize the liquid is provided to form a liquid ejection device. Therefore, the cover of the liquid flow path is formed as a movable thin film, the amount of deformation can be sufficiently large, and the liquid can be pressurized and discharged with good driving efficiency, so that mass production is easy, small size and high density arrangement are possible. A liquid ejection device is provided.

According to a second aspect of the present invention, in the liquid ejecting apparatus according to the first aspect, the pressurizing means includes an electrode provided on the thin film and an electrode provided opposite to the electrode. The thin film is deformed by an electrostatic force by applying a drive voltage between the thin film and the electrode.

According to the present invention, on a deposited thin film,
An electrode for applying a driving voltage and its counter electrode are provided, and the thin film is deformed by electrostatic force to discharge the liquid.Therefore, the movable thin film can be easily formed. A liquid ejection device capable of ejecting a liquid is provided.

According to a third aspect of the present invention, in the liquid ejecting apparatus according to the second aspect, the other electrode is provided above the thin film and supported by a supporting member. I do.

According to the present invention, the driving voltage for deforming the thin film by the electrostatic force is applied between the electrode provided on the thin film and another electrode provided on the thin film via the support member. Since the voltage is applied, it can be arranged close to each other, and since the thin film is convex upward, the stress due to the deformation caused by the action with the other electrode on the upper part is reduced,
The thin film driving with a large deformation amount is performed more efficiently.

According to a fourth aspect of the present invention, in the liquid ejecting apparatus according to any one of the first to third aspects, the material of the thin film is silicon.

According to the present invention, since the liquid ejecting apparatus is formed by depositing a thin film made of silicon, a liquid ejecting apparatus which is hardly affected by ink or the like and which can be easily finely processed is provided.

According to the liquid ejecting apparatus of the fifth aspect,
The liquid ejecting apparatus according to any one of claims 1 to 4, wherein the thickness of the thin film is in a range of 0.1 µm to 5 µm.

According to the present invention, the liquid discharge device is formed by depositing a thin film with a thickness of 0.1 μm to 5 μm to form a liquid discharge device. Therefore, the liquid discharge device can be driven efficiently and can secure a sufficient liquid discharge amount. Is provided.

According to the liquid ejecting apparatus of the sixth aspect,
The liquid ejecting apparatus according to any one of claims 1 to 4, wherein a thickness of the thin film is in a range of 0.1 µm to 2 µm.

According to the present invention, the thin film is deposited to a thickness of 0.1 μm to 2 μm to form the liquid discharge device, so that the film formation time can be shortened and the liquid discharge performance can be further improved. A dispensing device is provided.

A method of manufacturing a liquid discharge device according to claim 7, wherein the substrate is processed by forming a plurality of liquid flow paths partitioned by a side wall and having a discharge port at least at one end; Filling the entire liquid flow path from the height of the upper end of each of the side walls to a convex shape between adjacent ones of the side walls, and depositing a thin film on each of the side walls and the filling. A thin film deposition step for removing the filler, and a pressurizing means for forming a pressurizing means for deforming the thin film to pressurize the liquid in the plurality of liquid flow paths and discharge the liquid from each of the discharge ports. And a forming step.

According to the present invention, a plurality of liquid flow paths are formed on the substrate by dividing the liquid flow paths by the side walls so as to form a groove, and the filling material is entirely filled in the liquid flow paths. In the meantime, a pressurizing means for pressurizing the liquid by deforming the thin film by forming a thin film thereon after removing the filler after embedding in a cross-sectional shape so as to have a convex shape above is formed. In this order, the manufacturing process was advanced to form a liquid discharge device. Therefore, it is possible to manufacture a small-sized, high-density liquid discharge device capable of discharging a liquid by pressurizing it with a large amount of deformation at a good driving efficiency by using a very thin movable thin film at a low cost and in a large amount. .

According to a eighth aspect of the present invention, there is provided the liquid ejecting apparatus manufacturing method according to the seventh aspect.
In the thin film volume step, a liquid filler that solidifies at a predetermined temperature is formed in the entire plurality of liquid flow paths, and has an upwardly convex shape between adjacent sidewalls from the height of the upper end of each sidewall. After filling and solidifying the filler by heating at the predetermined temperature, the thin film is deposited on each of the side walls and the filler, and then the filler is dissolved and removed with a solvent. And

According to the present invention, a liquid filler which solidifies at a predetermined temperature is buried in the entire liquid flow passage so as to have a convex shape, which is heated at the predetermined temperature to be solidified. Is deposited, and the filler is dissolved and removed with a solvent. Therefore, a thin film can be easily deposited, and the liquid discharge apparatus can be manufactured at a lower cost and in a larger quantity.

According to a ninth aspect of the present invention, there is provided the liquid ejecting apparatus manufacturing method according to the eighth aspect.
When the filler is heated and solidified at the predetermined temperature,
It is characterized in that the volume expands.

According to the present invention, when the filling material is buried in the entire liquid flow path, and is heated and solidified at a predetermined temperature, the volume of the filling material expands, and as a result, the cross-sectional shape which is naturally convex upward is obtained. Becomes Therefore, a liquid ejecting apparatus which can easily form a thin film having a convex cross section with an upward cross section, and which can easily change the size of the convex shape by adjusting the expansion coefficient of the filler, and which has a large deformation amount and good driving efficiency. Can be easily manufactured.

According to a tenth aspect of the present invention, there is provided the liquid ejecting apparatus manufacturing method according to the eighth or ninth aspect, wherein the heating is performed while the liquid ejecting apparatus faces downward during the heating. It is characterized by doing.

According to the present invention, the liquid discharge device in which the filler is embedded is heated in a downward state so that the filler is solidified. In addition, the convex shape can be further enlarged, and the liquid discharge device having a larger deformation amount and good driving efficiency can be easily manufactured.

[0027] According to a eleventh aspect of the present invention, in the liquid ejecting apparatus manufacturing method according to any one of the seventh to tenth aspects, the substrate having the plurality of liquid flow paths formed thereon is formed on the substrate. In addition, the inner surface of each of the liquid flow paths is subjected to a surface treatment capable of increasing the wettability to the filler as compared with the upper end of each of the side walls, and then the filler is embedded.

According to the present invention, prior to the filling, the surface treatment is performed so that the wettability to the filling is relatively high at the surface of each of the liquid flow paths and relatively low at the upper end of each of the side walls. Since the filler is applied, the affinity with each liquid flow path surface is increased, while the affinity with the upper end of each side wall is reduced, so that an upwardly convex shape is easily formed, so that manufacturing is facilitated. be able to.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the following description, an embodiment in which a substrate on which a plurality of liquid flow paths are formed is processed to manufacture a liquid ejection apparatus in which a thin film that functions as a pressurizing unit that pressurizes the liquid in each liquid flow path is formed. Will be described.

First, the step of forming the liquid flow channel 12 in the silicon single crystal substrate 1 will be described with reference to FIG. In the present embodiment, as the substrate material for forming the liquid flow path 12, glass or various resins can be used in addition to the silicon single crystal. Here, a silicon single crystal which is easy to process and has good mass productivity is used. A case where a crystal is used as a substrate material will be described.

FIG. 1A is a perspective view showing patterning performed on a silicon single crystal substrate 1 by using photolithography. A side wall 11 (FIG. 1) that partitions a plurality of liquid channels 12 formed in a groove shape on a silicon single crystal substrate 1
The position corresponding to (b)) is masked with the resist 10.
At this time, the liquid flow path 12 not masked by the resist 10
Has a width of 10 μm or less and a length of about 2 mm or less. Further, the thickness of the resist 10 may be any thickness that is sufficient to hold the resist 10 during etching described later.

FIG. 1B shows that the silicon single crystal substrate 1 patterned in FIG. 1A is etched to form a groove-like liquid flow path 12 partitioned by a plurality of side walls 11. FIG. As this etching, in addition to wet etching using a chemical, dry etching using plasma or the like having excellent fine processing properties can be performed. Note that if dry etching using plasma or the like is performed, anisotropic etching can be performed, so that each liquid flow path 12 can easily have a rectangular cross-sectional structure having a vertical side surface and a horizontal bottom surface. Each liquid channel 1
After the etching is performed until the depth becomes approximately the same as the width of the substrate 2, the resist 10 is removed, and a plurality of liquid flow paths 12 partitioned on each side wall 11 are formed in the silicon single crystal substrate 1. .

Next, a process of embedding the filler 13 in each liquid channel 12 of the silicon single crystal substrate 1 will be described with reference to FIG. In the present embodiment, since the filler 13 embedded in each liquid channel 12 serves as a base for thin film deposition, a resist that solidifies at a constant temperature is used as the filler 13.

Here, it is desirable that a surface treatment is performed on the silicon single crystal substrate 1 before the filling 13 is buried. That is, the silicon single crystal substrate 1
The surface of each liquid channel 12 and the upper end of each side wall 11 are entirely subjected to a hydrophilic treatment or a hydrophobic treatment.
Since the resist used as the filler 13 has a low affinity for water, it is possible to increase the wettability to the resist by applying a hydrophobic treatment, and to reduce the wettability to the resist by applying a hydrophilic treatment. Can be.

Therefore, the hydrophilicity is applied to the upper end of each side wall 11 to lower the wettability, and the hydrophobicity is applied to the surface of each liquid flow path 12 to increase the wettability. When the filling 13 is filled, the surface of each liquid flow path 12 is relatively easily drawn toward the surface of each liquid channel 12 as compared with the upper end portion of each side wall 11, and an upwardly convex surface state is easily formed.

In addition, when a normal positive resist is used, the hydrophilic treatment is simply performed on the upper end of each side wall 11.
This is effective because a difference in relative affinity occurs. For example,
Before processing the silicon single crystal substrate 1, a metal which is easily oxidized such as tantalum is formed, and then the liquid flow path 12 is processed, so that only the upper end of each side wall 11 is formed. A state in which the filmed metal remains can be formed. At this time, since the metal such as tantalum has a high hydrophilicity, it is possible to give a difference in relative wettability with the surface of each liquid channel 12. When processing is performed using tantalum, since etching can be performed in the same manner as silicon using fluorine-based plasma, there is an advantage in that there is no need to change processing of the silicon single crystal substrate 1.

[0037] Conversely, the hydrophobic treatment may be performed only on the surface of each liquid flow channel 12. In addition, since the hydrophilic treatment and the hydrophobic treatment depend on the properties of the material used as the filler 13, a treatment method suitable for each can be used, and further, there is a case where no treatment is required.

FIG. 2A is a perspective view showing a state in which the inside of the liquid channel 12 formed in the silicon single crystal substrate 1 is backfilled with the filler 13. That is, in each liquid channel 12,
A liquid resist is injected as the filling material 13,
The surface coincides with the upper end of the side wall 11 and each side wall 11
Between them, the cross section has an upward convex shape. Therefore, the filling material 13 is injected so as to have a larger amount than the volume of each liquid flow path 12, and on the surface thereof, by the action of surface tension,
An upwardly convex state having a predetermined curvature is set. Then, when the silicon single crystal substrate 1 is heated at a temperature equal to or higher than the predetermined temperature, the filler 13 is solidified while maintaining the upwardly convex shape.

FIG. 2B is a cross-sectional view of the single crystal silicon substrate 1 in which the filler 13 is buried in FIG. As shown in FIG. 2B, the surface of the silicon single crystal substrate 1 has a concave-convex surface 14 in the shape of a semicylindrical shape in which the upper ends of the side walls 11 and the fillers 13 are alternately arranged. That is, on the uneven surface 14, a shape in which the upper end portion of each side wall 11 becomes a bottom and an upwardly curved portion in an intermediate portion between the side walls 11 is repeated at a constant pitch.

Here, in order to obtain the uneven surface 14,
As described above, in addition to injecting a large amount of the filler 13 into each of the liquid flow paths 12, a material having a characteristic that the volume expands when heated and solidified may be used as the filler 13. That is, when a resist having a large expansion coefficient is injected into each liquid channel 12 and solidified by heating, the volume increases and the upward convex shape between the side walls 11 can be further increased.

Further, the silicon single crystal substrate 1 into which the filling 13 has been injected may be turned upside down and solidified by heating with the surface of the filling 13 facing downward. Thereby, the upward convex shape between the side walls 11 can be further increased by the weight of the filler 13. By combining these methods, it is possible to appropriately adjust the size of the convex shape when the filler 13 is solidified.

Next, a process of depositing a thin film 15 on the uneven surface 14 of the silicon single crystal substrate 1 formed as described above will be described with reference to FIG.

FIG. 3A is a perspective view showing a state in which a thin film 15 is deposited on the uneven surface 14 of the silicon single crystal substrate 1 by using an appropriate thin film forming technique. As this thin film forming technique, a physical thin film forming method such as vacuum deposition, sputtering, or ion plating may be used. Further, the material of the thin film 15 to be deposited may be any material as long as it has a property not to be affected by the liquid in the liquid flow path 12 such as ink. For example, the thin film 15 can be deposited by using a material that is made of silicon that is hardly affected by ink or the like and by using a sputtering method. Further, even if the material is easily eroded by ink or the like, it can be used if the protection treatment is performed with an insulator.

In the present embodiment, the thickness of the deposited thin film 15 is set to 0.1 μm in consideration of the vibration characteristics and the liquid discharge amount.
A suitable range is from m to 5 μm. When the film formation time and film properties are comprehensively considered within this range, the thickness of the thin film 15 is set to 0.1 μm to 2 μm.
It is preferable to set it in the range. If the thin film 15 is too thick, the driving voltage for pressurizing the liquid in the liquid flow path 12 becomes too high, and if the thin film 15 is too thin, the spring property becomes small and the liquid in the liquid flow path 12 is discharged. It becomes difficult. The optimum thickness of the thin film 15 depends on the properties of the liquid to be pressurized and the shape of the liquid channel 12.

FIG. 3B is a perspective view showing a state in which the solidified filler 13 has been removed from the silicon single crystal substrate 1. That is, since the deposition of the thin film 15 is completed, the unnecessary filler 13 is removed, and the liquid flow path 12 partitioned by each side wall 11 is formed in a state where the upper portion is covered by the thin film 15. At this time, the thin film 15 is
1 and has an upwardly convex shape between the side walls. Thus, the volume of each liquid flow path 12 is increased by the convex shape of the thin film 15.

In this embodiment, the silicon single crystal substrate 1 in which the filler 13 is embedded is immersed in a solvent such as a resist removing liquid for a certain period of time to dissolve and remove the filler 13.
At this time, the solvent penetrates through the opening at one end of each liquid channel 12 of the silicon single crystal substrate 1 and dissolves the filler 13 in about 20 to 30 minutes.

Next, referring to FIG.
A process of forming an electrode for deforming the thin film 15 by electrostatic force will be described.

FIG. 4A is a perspective view showing a state in which a plurality of independent electrodes 17 are formed along the upper portions of the respective liquid channels 12 via the insulating film 16 on the thin film 15. Here, since the plurality of independent electrodes 17 need to be electrically separated from each other, the insulating film 16 is formed over the entire thin film 15. The insulating film 16 can also be formed by using the above-described physical thin film forming method, but may be formed by using a chemical thin film forming method since an inorganic material is used.

The plurality of independent electrodes 17 are provided on the insulating film 16 so as to extend along the respective liquid channels 12, and are individually connected to control wirings 17a so that they can be individually controlled. Therefore, it is possible to individually discharge the liquid in each liquid channel 12.

FIG. 4B is a perspective view showing a state in which a plurality of girders 18 are attached between the independent electrodes 17 on the insulating film 16. The plurality of girders 18 serve as support members for supporting a common electrode 19 (FIG. 4C) described later. FIG.
As shown in (b), it is arranged at a position overlapping the upper portions of the plurality of side walls 11.

Although the material of the beam 18 can be selected relatively freely, it is preferable to use an inorganic material in the case where the material is attached by anodic bonding without using an adhesive. Multiple digits 18
May be formed on the insulating film 16 and then etched to form the shape of the spar 18. Also, the height of each spar 18 must be sufficiently higher than the upwardly convex portion between the side walls 11.

FIG. 4C is a perspective view showing a state in which a common electrode 19 is formed on a plurality of girders 18 as support members. The common electrode 19 is made of metal or the like, and is arranged so as to cover the entire silicon single crystal substrate 1. Then, a voltage is applied in a state where the thin film 15 is opposed to the plurality of independent electrodes 17 described above, and acts to deform the thin film 15 up and down by mutual electrostatic force. The control electrode 1 is also provided on the common electrode 19.
9a is provided.

Next, the operation of the liquid ejection apparatus formed as described above will be described with reference to FIG.

FIG. 5A is a cross-sectional view of the liquid discharge device, showing a state in which a drive voltage is applied so that the independent electrode 17 and the common electrode 19 are charged with the same sign. It is. In FIG. 5A, the liquid flow path 1
One independent electrode 1 formed via an insulating film 16 on
7 is applied with a predetermined positive voltage, and its surface is positively charged. Similarly, a predetermined positive voltage is applied to the common electrode 19 supported by the plurality of girders 18 and opposed to each of the independent electrodes 17, and the surface thereof is positively charged. Therefore, the independent electrode 17 and the common electrode 19 repel each other due to the repulsive action of the static electricity, and the thin film 15 in a portion covering one liquid flow path 12 located below the independent electrode 17 is deformed downwardly convex. Therefore, the volume of the liquid flow path 12 is reduced and pressure is applied to the liquid inside, so that the liquid is discharged from the discharge port.

At this time, the deformed portion of the thin film 15 has an upwardly convex shape when no driving voltage is applied, and when the thin film 15 is forcibly deformed downwardly as described above, the portion from the upwardly convex portion to the downwardly convex portion is formed. It is displaced by a large width until it becomes a convex state, and the volume of the liquid flow path 12 is largely changed by that amount, so that pressurization can be performed efficiently. Moreover, since the thin film 15 is formed in the upwardly convex shape as described above, the surface area thereof is larger than that in the case where the thin film 15 is formed flat, so that a larger amount of deformation can be secured.

FIG. 5B shows a state in which a drive voltage is applied to each of the independent electrode 17 and the common electrode 19 so that electric charges of different signs are charged. In FIG. 5B, unlike FIG. 5A, a predetermined negative voltage is applied to one of the independent electrodes 17 so that the surface thereof is negatively charged. The surface is positively charged by applying a positive voltage. Therefore, the independent electrode 17 and the common electrode 19 are attracted to each other by the action of electrostatic attraction, and the thin film 15 at a portion covering one liquid flow path 12 located below the independent electrode 17 has a higher convexity than the original convex shape. Deformed into shape. Therefore, the volume of the liquid flow path 12 increases and the pressure of the liquid inside decreases, and the liquid is sucked from the opening formed at one end. Then, when the application of the driving voltage to the independent electrode 17 and the common electrode 19 is stopped, the deformed thin film 15 returns to its original state, so that the volume of the liquid flow path 12 decreases and returns to its original state. The liquid inside is pressurized, and the liquid is discharged from the discharge port.

At this time, the deformed portion of the thin film 15 is deformed upward from the original convex shape when the driving voltage is not applied. Displaced until it becomes a large convex shape. At this time, in the vicinity of the original convex shape, the stress due to the vertical deformation of the thin film 15 can be reduced, and efficient driving can be performed. For example, when discharging fine droplets,
It is also an effective driving method to slightly deform the thin film 15 vertically near the upward convex shape.

The common electrode 19 does not necessarily have to be common to the entire surface, and may be configured to correspond to each individual electrode 17. Further, the discharge ports formed in the liquid flow path 12 may be formed on any of the six surfaces surrounding the liquid flow path 12 as long as liquid discharge is possible.

Next, the relationship between the driving conditions for discharging the liquid and the thickness of the thin film 15 will be described. First, thin film 1
In the case of driving by deforming 5 by electrostatic force,
The displacement of the thin film 15 is represented by the following equation.

[0060]

(Equation 1) Here, W: displacement amount of the thin film 15 (m) P: pressure (N / m2) h: thickness of the thin film 15 (m) a: half of the width of the liquid channel 12 (m) E: Young's modulus On the other hand, static electricity The suction pressure by the force is expressed by the following equation.

[0061]

(Equation 2) Here, p: adsorption pressure (N / m2) ε: dielectric constant (F / m) V: drive voltage (V) t: gap (m) between the thin film 15 and the common electrode 19 It can be approximated as follows.

[0062]

(Equation 3) However, M: the amount of volume deformation (m3) b: the length of the long side of the liquid flow path 12 The calculation may be performed using the equations shown in Equations 1 to 3 above. Here, as an example, h = 1 μm, t = 1 μm, ε
= 8.8 × 10 −12 (in vacuum) and E = 11 × 10 10 (Young's modulus of silicon) to determine the relationship between the drive voltage V and the volume deformation M. At this time, since the volume deformation amount M corresponds to the liquid discharge amount discharged from the liquid flow path 12, the relationship between the drive voltage V and the liquid discharge amount can be understood. As a result of the calculation, when V = 50 (V), the liquid ejection amount is 0.28 (p
l), when V = 100 (V), the liquid ejection amount 1.1 (p
l), when V = 150 (V), the liquid ejection amount 2.5 (p
l), when V = 200 (V), the liquid ejection amount is 4.5 (p
1).

On the other hand, as another calculation example, when the thickness h of the thin film 15 is twice as large as the above example, that is, h = 2 μm
The relationship between the drive voltage V and the liquid ejection amount is obtained by performing calculations for the case where. Then, when V = 50 (V), the liquid ejection amount is 0.03 (pl), when V = 100 (V), the liquid ejection amount is 0.13 (pl), and when V = 150 (V), the liquid ejection amount is 0. .31 (pl), when V = 200 (V), the liquid ejection amount is 0.55 (pl), and when V = 500 (V), the liquid ejection amount is 3.48 (pl). It can be seen that the liquid ejection amount with respect to the voltage is significantly reduced.

Therefore, in order to efficiently drive the thin film 15 at a lower driving voltage, it is advantageous to reduce the thickness of the thin film 15. Actually, the optimum thickness is set in consideration of the strength of the thin film 15 and the difficulty of film formation. The thickness of the thin film 15 is desirably 5 μm or less as described above.
When the thickness is in the range from 1 μm to 2 μm, it is possible to obtain an overall excellent liquid ejecting apparatus.

Thus, according to the liquid ejecting apparatus according to the present embodiment, the repulsion and the suction action by the electrostatic force are used to
The thin film 15 can be deformed in a wide range from the upwardly convex state to the downwardly convex state, and a liquid discharge with high drive efficiency that allows a large volume change of the liquid flow path 15 can be performed. Further, since the thickness of the thin film 15 can be made extremely thin, the pressure on the liquid can be performed with a smaller driving voltage. In particular, in the vicinity of the upwardly convex state, pressure can be applied with a smaller driving voltage. Furthermore, since the surface area of the thin film 15 is sufficiently large, the amount of deformation can be increased accordingly, and efficient driving can be performed.

Further, according to the manufacturing method of the liquid discharge apparatus according to the present embodiment, the filling material 13 is once embedded between the side walls 11 so as to have an upwardly convex surface shape, and the thin film 15 is deposited thereon. After that, the filling material 13 is removed, so that the thin film 15 is formed on the side wall 11 partitioning each liquid flow path 12, and the thin film 15 serving as the uneven surface is
A relatively complicated structure can be realized relatively easily.
In addition, a common electrode 17 is provided on the thin film 15 and a common electrode 19 is further disposed on the thin film 15 so that the thin film 15 also functions as a movable thin film. Therefore, a liquid discharge device having a complicated and fine structure can be provided. In addition, mass production can be performed at low cost.

In the above-described embodiment, several liquid flow paths 12 are provided in the silicon single crystal substrate 1 of the liquid discharge device.
Has been described, but in practice, a larger number of liquid flow paths 12 can be formed to manufacture a liquid ejecting apparatus. For example, it is possible to manufacture a liquid ejection device in which hundreds to thousands of liquid channels 12 are arranged in parallel.

Further, in the above-described embodiment, the case where the method of deforming the thin film 15 using electrostatic force is used as the pressurizing means of the liquid ejecting apparatus, but other pressurizing means are used. Is also good. For example, the pressing means may be configured using a piezoelectric element.

Further, in the embodiment described above, the case where a resist that solidifies at a constant temperature is used as the filler 13 that fills the groove serving as the liquid flow path 12 has been used. The groove may be filled with (wax) or the like. When this wax is used, the liquid flow path 12 is naturally cooled.
Solidifies inside and fills the groove. And thin film 1
When the filler 13 is removed after the formation of 5, the wax is evaporated and removed by heating instead of using a solvent.

The liquid ejection device according to the embodiment described above can be easily applied to an ink jet head.
For example, if the liquid inside each liquid flow path 12 is used as ink, ink is supplied from an opening formed at one end thereof, and a nozzle is formed at the other end to discharge ink.
An ink jet head can be easily realized. In this case, by applying the present invention, it is possible to easily manufacture a high-density inkjet head in which, for example, 2400 or more liquid flow paths 12 exist in one inch, and control area gradation and the like. Can be easily performed.

Further, the liquid ejecting apparatus according to the embodiment described above can be used for various micro instruments and devices such as a pipette for micro titration as an application field of micro machining technology. .

[0072]

According to the first aspect of the present invention, the cover of the liquid flow path is formed as a movable thin film having an upward convex shape on the liquid flow path, and this thin film is formed with good driving efficiency and large deformation. A liquid ejecting apparatus which can be driven to eject a liquid, can be easily mass-produced, and can be arranged in a small size and high density can be realized.

According to the second aspect of the present invention, an electrode is provided on the deposited thin film, the thin film can be deformed by electrostatic force to discharge a liquid, and a movable thin film can be easily formed. A liquid ejecting apparatus capable of ejecting a liquid by driving a low voltage to obtain a large amount of deformation can be realized.

According to the third aspect of the present invention, since the driving is performed by applying the driving voltage to the electrode provided on the thin film, the thin film driving which can efficiently deform the thin film with less stress is provided. A possible liquid ejection device can be realized.

According to the fourth aspect of the invention, since the material of the thin film is made of silicon, it is possible to realize a liquid ejecting apparatus which is hardly corroded by ink or the like and which can be easily finely processed.

According to the fifth aspect of the present invention, since the thickness of the thin film is set to 0.1 μm to 5 μm, it is possible to realize a liquid ejecting apparatus capable of obtaining high driving efficiency and a sufficient liquid ejecting amount.

According to the sixth aspect of the present invention, since the thickness of the thin film is set to 0.1 μm to 2 μm, it is possible to realize a liquid discharge apparatus having better discharge performance in a short film forming time.

According to the seventh aspect of the present invention, a very thin movable thin film can be formed to discharge a liquid with a large amount of deformation at a good driving efficiency, and a liquid discharge that can be arranged compactly and with high density. The device can be manufactured inexpensively and in large quantities.

According to the eighth aspect of the present invention, a thin film having an upward convex shape is easily deposited, so that good driving efficiency can be obtained, and a small-sized and high-density liquid ejecting apparatus can be manufactured inexpensively and in large quantities. Can be manufactured.

According to the ninth aspect of the present invention, an upwardly convex thin film can be easily deposited, the convex shape can be adjusted, good driving efficiency can be obtained, and a liquid that can be arranged in a small size and high density can be obtained. Discharge devices can be manufactured inexpensively and in large quantities.

According to the tenth aspect of the present invention, there is provided a liquid ejecting apparatus capable of easily depositing a thin film having an upward convex shape, obtaining good driving efficiency with a larger amount of deformation, and being compact and capable of high-density arrangement. It can be manufactured inexpensively and in large quantities.

According to the eleventh aspect of the present invention, the surface treatment is performed such that the wettability to the filler is relatively higher on the surface of each liquid flow path than on the upper end of each side wall. Due to the difference in affinity, the upward convex shape is more easily formed, and the liquid discharge device can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a step of forming a liquid flow path in a silicon single crystal substrate in an embodiment of the present invention, wherein (a) is a perspective view showing patterning of the silicon single crystal substrate using photolithography, FIG. 4B is a perspective view showing a state in which a groove-like liquid flow path is formed in the silicon single crystal substrate by etching.

FIGS. 2A and 2B are diagrams illustrating a process of embedding a filler in an ink flow path of a silicon single crystal substrate in the embodiment of the present invention. FIG. A perspective view showing a returned state, (b) is X- of (a).
It is X sectional drawing.

FIG. 3 is an explanatory view of a step of depositing a thin film on the uneven surface of a silicon single crystal substrate in the embodiment of the present invention;
(A) is a perspective view showing a state in which a thin film is deposited on an uneven surface of a silicon single crystal substrate, and (b) is a perspective view showing a state in which a filler is removed from the silicon single crystal substrate.

FIG. 4 is an explanatory view of a step of forming an electrode for deforming the thin film by electrostatic force on the thin film in the embodiment of the present invention, wherein (a) shows each liquid flow path on the thin film via an insulating film; FIG. 3B is a perspective view showing a state in which a plurality of independent electrodes are respectively formed along the upper part of FIG. 3B; FIG. 3B is a perspective view showing a state in which a plurality of girders are attached between the independent electrodes on the insulating film; Is a perspective view showing a state where a common electrode is formed on a plurality of girders.

5A and 5B are diagrams for explaining the operation of the liquid ejection apparatus according to the embodiment of the present invention. FIG. 5A shows a state in which a drive voltage is applied so that the independent electrode and the common electrode are charged with the same sign. FIG. 4B is a cross-sectional view of the liquid discharge device in a state where a drive voltage is applied so that charges of different signs are respectively charged to the independent electrode and the common electrode.

[Description of Signs] 1 ... Single-crystal silicon substrate 10 ... Resist 11 ... Side wall 12 ... Liquid flow path 13 ... Filling material 14 ... Uneven surface 15 ... Thin film 16 ... Insulating film 17 ... Independent electrode 18 ... Girder 19 ... Common electrode

Claims (11)

[Claims] A substrate having a plurality of liquid channels formed in a groove shape and having at least one end provided with a discharge port; and an upper end portion of each of the side walls serving as a cover for covering the entire plurality of liquid channels. And a pressurizing unit configured to press the liquid in each of the liquid flow paths by deforming the thin film and discharge the liquid from each of the discharge ports. A liquid ejecting apparatus characterized by being formed in the entire flow passage so as to have an upwardly convex shape between adjacent side walls from the height of the upper end of each side wall. 2. The pressure means applies a drive voltage between an electrode provided on the thin film and another electrode provided opposite the electrode, and deforms the thin film by electrostatic force. The liquid ejecting apparatus according to claim 1, wherein 3. The liquid ejecting apparatus according to claim 2, wherein the other electrode is provided on the thin film and supported by a support member. 4. The liquid ejecting apparatus according to claim 1, wherein the material of the thin film is silicon. 5. The thickness of the thin film is from 0.1 μm to 5 μm.
The liquid ejection device according to claim 1, wherein the value is within a range of m. 6. The thin film has a thickness of 0.1 μm to 2 μm.
The liquid ejection device according to claim 1, wherein the value is within a range of m. 7. A substrate processing step of processing a substrate to form a plurality of liquid flow paths partitioned by a side wall and having a discharge port at least at one end; A thin film for filling a filling material so as to have an upwardly convex surface shape between the adjacent side walls from the height of the upper end portion, depositing a thin film on each of the side walls and the filling material, and then removing the filling material A depositing step, and a pressurizing means forming step of forming a pressurizing means for deforming the thin film to pressurize the liquid in the plurality of liquid flow paths and discharge the liquid from each of the discharge ports. Liquid ejecting apparatus manufacturing method. 8. The thin film volume step includes: filling a liquid filler solidifying at a predetermined temperature in the entire plurality of liquid flow paths from the height of the upper end of each of the side walls to the space between the adjacent side walls. Embedded in a convex surface shape, heated at the predetermined temperature to solidify the filler, depositing the thin film on each of the side walls and the filler, and then dissolving the filler in a solvent. The method for manufacturing a liquid ejection device according to claim 7, wherein the liquid ejection device is dissolved and removed. 9. The method according to claim 8, wherein the filling expands in volume when heated and solidified at the predetermined temperature. 10. The method for manufacturing a liquid ejection device according to claim 8, wherein the heating is performed while the liquid ejection device is facing downward during the heating. 11. A surface on which the plurality of liquid flow paths are formed, the inner surface of each liquid flow path having a higher wettability to the filler than the upper end of each side wall. The method according to any one of claims 7 to 10, wherein the filling is performed after the treatment.