JP2009228799A - Micro valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a microvalve having a groove capable of leading a fluid even when a valve body is pressed against a valve seat substrate provided with a lead-out port.
A valve body is provided so as to face a valve seat substrate, and the valve body is displaced by electrostatic attraction between an electrode provided on the valve body and an electrode provided on the valve seat substrate. In the microvalve for controlling the inflow amount of the introduction port through which the fluid provided on the substrate flows, the back plate provided on the opposite side of the valve seat substrate across the valve body, and the back plate provided on the back plate and the fluid An outlet port that flows out, a protrusion provided on the valve seat substrate and surrounding the introduction port, and an insulating film provided on the valve body so as to face the protrusion. And
[Selection] Figure 1

Description

  The present invention relates to a microvalve, and more particularly to a microvalve that controls high pressure and minute flow rate.

FIG. 8 is a schematic perspective view showing a conventional basic structure and partially broken.
A rectangular plate-shaped valve seat substrate 1 having a valve hole 4 penetrating in the thickness direction, a rectangular frame-shaped frame portion 5 and a frame portion fixed to one surface side (the upper surface side in FIG. 8) of the valve seat substrate 1 A valve body forming substrate 2 having a valve body portion 6 arranged inside and outside the valve hole 4 to open and close the valve hole 4 and having a movable electrode 8 formed on the opposite side of the valve body portion 6 from the valve seat substrate 1. A space 13 that is fixed to the opposite side of the substrate 2 from the valve seat substrate 1 and enables the displacement of the valve body 6 between the valve body forming substrate 2 and a space 13 that communicates with the fluid inlet 15 is formed. And a fixed electrode forming substrate 3 on which a fixed electrode 12 facing the movable electrode 8 is formed.
In addition, the diaphragm portion 7 is formed integrally with the frame portion 5 and can be bent in the thickness direction. A valve body portion 6 is provided continuously at the center of the diaphragm portion 7. A plurality (two in the illustrated example) of channel holes 10 serving as fluid channels between 15 and the valve hole 4 are provided in the thickness direction.
The fixed electrode forming substrate 3 is formed with a channel recess 11 in which a surface facing the valve element forming substrate 2 and one side surface are open, and the channel electrode is formed on the one side of the fixed electrode forming substrate 3. A space surrounded by the inner surface of the recess 11 and the exposed surface of the bonding layer 14 forms a fluid inlet 15. An insulating layer 9 that prevents conduction between the movable electrode 8 and the fixed electrode 12 is formed on the surface of the movable electrode 8.

The function of the microvalve will be described.
When no voltage is applied between the movable electrode 8 and the fixed electrode 12, the valve hole 4 is closed by the valve body 6. On the other hand, when a voltage higher than a specified voltage is applied between the movable electrode 8 and the fixed electrode 12 from a drive voltage source (not shown), the valve body portion 6 is displaced in a direction away from the valve hole 4 so that the valve Since the hole 4 is opened, the fluid flows through the path of the inlet 15 -the space 13 -the channel hole 10 of the diaphragm portion 7 -the valve hole 4. In short, a normally closed type micro valve is configured.

JP 2007-71257 A

However, such microvalves have the following problems.

When the valve body is pressed against the valve hole by the pressure of the gas that flows in, the valve body remains in the pressed state, so that the fluid does not flow and the flow path is blocked. .
When the flow path is blocked, conventionally, the introduced fluid is removed or the applied voltage is increased to displace the pressed valve body in the direction in which it cannot be pressed. It was.

  Therefore, the present invention eliminates the disadvantages of the prior art as described above, and realizes a microvalve having a groove that can lead out fluid even when the valve body is pressed against a valve seat substrate provided with a lead-out port. It is intended to do.

In order to achieve the above object, according to claim 1 of the present invention, a valve body is provided opposite to a valve seat substrate, and an electrode provided on the valve seat and an electrode provided on the valve seat substrate are provided. In the microvalve for controlling the inflow amount of the introduction port through which the valve body is displaced by electrostatic attraction and the fluid provided in the valve seat substrate flows, provided on the opposite side of the valve seat substrate with the valve body interposed therebetween A back plate that is provided on the back plate and through which the fluid flows out, a projection that is provided on the valve seat substrate and that surrounds the introduction port, and is opposed to the projection. And an insulating film provided on the valve body.

  According to a second aspect of the present invention, in the microvalve according to the first aspect, the outlet port is provided with a groove for guiding a fluid even when the valve body is pressed against the back plate.

According to a third aspect of the present invention, in the microvalve of the first aspect, the protrusion is circular.

  According to a fourth aspect of the present invention, in the microvalve of the first aspect, the valve body forming substrate and the valve body are supported through a beam and are integrally formed.

  According to a fifth aspect of the present invention, in the microvalve of the fourth aspect, the valve body forming substrate, the valve body, and the beam are made of silicon.

The effects obtained by the typical inventions among those disclosed in the present application will be described as follows.

  Even when the valve body is pressed against the back plate provided with the outlet, the fluid can be led out by providing the groove.

  Hereinafter, the microvalve 20 of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of the present invention.

A substrate using a substrate made of Pyrex (registered trademark) is used as the valve seat substrate 21 and the back plate 22.
The valve seat substrate 21 and the back plate 22 may employ other materials.

The microvalve 20 has an inlet 26 through which a fluid flows, a protrusion 32 provided so as to surround the inlet 26, a valve seat substrate 21 having the protrusion 32, and the valve seat substrate 21. A valve body 24 provided on the opposite side of the valve seat substrate 21 across the valve body 24, a lead-out port 27 provided on the back plate 22 and through which a fluid flows out, and a valve A valve body forming substrate 23 for supporting the body 24 via the beam 25, an electrode provided on the surface of the valve body 24 facing the valve seat substrate 21, an insulating film 31 provided on the surface of the electrode, It is comprised from the electrode of the surface which opposes the valve body 24 of the seat substrate 21. FIG. An electrostatic gap 28 is provided between the valve body 24 and the valve seat substrate 21.
Note that the protrusion 32 may be circular.

In addition, an electrode (hereinafter referred to as a valve body forming substrate side electrode 29) extending from the valve seat substrate 21 to the valve body forming substrate 23 is formed, and the inlet 26 and the valve body 24 of the valve seat substrate 21 and the valve are formed. A valve seat substrate side electrode 30 is formed at a portion where the seat substrate 21 contacts.
In addition, the valve body formation board | substrate side electrode 29 and the valve seat board | substrate side electrode 30 are comprised by the metal thin film.

Further, a valve body 24 and a beam 25 are formed on the valve body forming substrate 23 by RIE deep drilling. And the valve body formation board | substrate 23 and the valve body 24 are supported via the beam 25, and the valve body formation board | substrate 23, the valve body 24, and the beam 25 are integrally formed with the electroconductive member. For example, silicon may be used for the conductive member, and other materials may be employed.

In this embodiment, since the valve forming substrate 23 is made of a conductive member, the valve forming substrate 23 functions as an electrode. When the valve forming substrate 23 is not a conductive member, an electrode is provided on the surface of the valve body 24 that faces the valve seat substrate 21.

Next, FIG. 2 shows an AA ′ cross-sectional view of FIG. In the figure, the same components as those in FIG.
The valve seat substrate 21 is formed with a valve body forming substrate side electrode 29 and a valve seat substrate side electrode 30 and an introduction port 26 for restricting fluid.

FIG. 3 is a cross-sectional view taken along the line BB ′ of FIG. In the figure, the same components as those in FIG.
On the valve body forming substrate 23, four beams 25 and an insulating film 31 that insulates the valve seat substrate side electrode 30 are formed.
Note that the number of beams 25 may be any number.

  FIG. 4 is an enlarged view of a portion C in FIG. In the figure, the same components as those in FIG.

The valve seat substrate 21 includes a protrusion 32 provided so as to surround the introduction port 26. In addition, the valve body 24 is provided with an insulating film 31 on the surface of the valve body 24 so as to face the protrusion 32.
A valve seat substrate gap 33 is provided between the protrusion 32 and the insulating film 31, and a back plate gap 34 is provided between the valve body 24 and the back plate 22.
Further, the valve seat substrate gap 33 represents the amount of displacement by which the valve body 24 can be displaced toward the valve seat substrate 21, and the back plate gap 34 represents the amount of displacement by which the valve body 24 can be displaced toward the back plate 22.
An electrostatic gap 28 is provided between the valve body 24 and the valve seat substrate 21.
The outlet 27 is provided with a groove (hereinafter referred to as an air groove 35) for leading the fluid even when the valve body 24 is pressed against the back plate 22.

  When a fluid flows through the microvalve 20, if a high pressure fluid flows from the inlet 26, a pressure difference may occur between the high pressure side inlet 26 and the low pressure side outlet 27. May be pressed against the back plate 22 depending on the magnitude of the differential pressure. Even when the valve body 24 is pressed against the back plate 22, by providing the air groove 35 for leading out the fluid, the inlet 26 -the valve seat substrate gap 33 -the electrostatic gap 28 without closing the flow path. -Fluid can flow through the path of the air groove 35-outlet 27.

When no fluid flows through the microvalve 20, for example, the back plate gap 34 is 0.5 μm, the thickness of the insulating film 31 is 1 μm, the valve seat substrate gap 33 is 0.5 μm, the protrusion 32 is 1 μm, static The electric gap 28 is set to 2.5 μm.
When a fluid with high pressure flows through the microvalve 20, the valve body 24 is pressed against the back plate 22, the back plate gap 34 becomes 0 μm, the valve seat substrate gap 33 becomes 1 μm, and the electrostatic gap 28 becomes 3 μm. This electrostatic gap 28 is an electrostatic gap 28 in the initial state.

Further, the electrostatic actuator is characterized in that it pulls in when it drives 1/3 or more of the initial gap.
Therefore, when the valve body 24 is pressed against the back plate 22, the dimensions of the gap and the like are 0.5 μm for the back plate gap 34, 1 μm for the insulating film 31 and 0 for the valve seat substrate gap 33 as in the above example. .5 μm, when the protrusion 32 is 1 μm and the electrostatic gap 28 is 2.5 μm, it is 1/3 or more of the initial gap, that is, 1 μm or more that is 1/3 or more of the value of the electrostatic gap 28 in the initial state. Since the body 24 cannot be driven, the pull-in is not performed.

Even in the case of Pull-in, the insulating film 31 does not short-circuit between the electrode on the surface of the valve seat substrate 21 facing the valve body 24 and the electrode provided on the surface of the valve body 24 facing the valve seat substrate 21. Can take structure.

  FIG. 5 is an explanatory diagram of the flow of the fluid according to the present invention, in which a voltage is applied to the electrostatic gap 28.

When no fluid of high pressure flows through the microvalve 20 and no voltage is applied from the drive voltage source 36 to the electrostatic gap 28, the valve body 24 is not displaced and the valve seat substrate gap 33 is not narrowed. The fluid can flow through the path of the inlet 26 -the valve seat substrate gap 33 -the electrostatic gap 28 -the back plate gap 34 or the air groove 35 -the outlet 27. The fluid flow 37 in this case is shown in the figure.

On the other hand, when a high-pressure fluid flows through the microvalve 20, the valve body 24 is pressed against the back plate 22.

When a voltage is applied to the electrostatic gap 28 in a state where the valve body 24 is pressed against the back plate 22, for example, the valve body 24 becomes “+” and the valve seat substrate 21 becomes “−”. And the valve seat substrate 21 attract each other, and the valve body 24 can be displaced in a direction away from the back plate 22.
That is, by applying a voltage to the electrostatic gap 28, the valve body 24 can be displaced in a direction approaching the valve seat substrate 21.

Further, when the amount of voltage applied to the electrostatic gap 28 is increased, the valve body 24 can be displaced in a direction further away from the back plate 22.

  When the valve body 24 is pressed against the valve seat substrate 21 by applying a voltage to the electrostatic gap 28, the valve body 24 is separated from the valve seat substrate 21 by reducing the voltage applied to the electrostatic gap 28. Can be displaced in the direction.

  Therefore, by changing the amount of voltage applied to the electrostatic gap 28, the valve body 24 can be arbitrarily driven, and a minute flow rate can be controlled.

  The initial electrostatic gap 28, the amount of movement of the valve body 24, and the drive voltage for controlling the valve body 24 are appropriately determined according to the dimensions of the back plate gap 34, the insulating film 31, the valve seat substrate gap 33, and the protrusion 32. Can be designed to

That is, the back plate gap 34, the initial electrostatic gap 28, the thickness of the insulating film 31, the valve seat substrate gap 33, the protrusion 32, the amount of movement of the valve body 24, and the driving voltage for controlling the valve body 24 are appropriately set. Accordingly, it is possible to realize the microvalve 20 that can obtain a large driving force in a range where the driving distance of the valve body 24 is small.
Therefore, a minute flow rate can be controlled.

  Further, in the case of pull-in and when the voltage applied from the drive voltage source 36 to the electrostatic gap 28 is increased, the microvalve 20 is completely closed by firmly pressing the insulating film 31 and the protrusion 32 together. It is possible to reduce fluid leakage in the state where

Further, since the flow path, that is, the path of the inlet 26 -the valve seat substrate gap 33 -the electrostatic gap 28 -the back plate gap 34 or the air groove 35 -the outlet 27 is on one axis, all the spaces are fluidized. Therefore, useless space can be reduced as compared with the prior art.
That is, since a useless space can be reduced as compared with the prior art, a small microvalve 20 can be realized.

  From the above, it is possible to produce a microvalve 20 for high pressure resistance and minute flow control using a small electrostatic actuator.

FIG. 6 shows a cross-sectional view of the entire structure of a microvalve for electrostatic drive type high withstand pressure and micro flow rate. In the figure, the same components as those in FIG.

The microvalve for electrostatic drive type high withstand pressure and minute flow is formed so that the microvalve 20 of FIG. 1 is sandwiched between ferrules 41, a tube 38 is provided inside a nut 39, and a voltage is applied to the electrostatic gap. An electrode extraction hole 42 is provided for each of the valve body forming substrate side electrode 29 and the valve seat substrate side electrode 30, and a body 40 is provided.

  FIG. 7 is a block diagram showing another embodiment of the present invention. In the figure, the same components as those in FIG.

By combining the microvalve 20 of Example 1 and the thermal flow meter 43, a micro mass flow controller can be manufactured.
In addition, a micro mass flow controller array can be manufactured in one wafer.

  This mass flow controller valve is made of silicon, pyrex (registered trademark), gold, platinum, or the like having high corrosion resistance, thereby controlling the flow rate of gas used in, for example, a microreactor, a fuel cell, or a semiconductor manufacturing apparatus. Suitable for

It is a block diagram which shows one Example of this invention. It is A-A 'sectional drawing of FIG. 1 of this invention. It is B-B 'sectional drawing of FIG. 1 of this invention. It is the enlarged view to which the C section of FIG. 1 of this invention was expanded. It is fluid flow explanatory drawing of this invention. 1 is an overall structural cross-sectional view showing an embodiment of the present invention. It is a block diagram which shows the other Example of this invention. It is a block diagram which shows an example of the past.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve seat board | substrate 2 Valve body formation board 3 Fixed electrode formation board 4 Valve hole 5 Frame part 6 Valve body part 7 Diaphragm part 8 Movable electrode 9 Insulating layer 10 Channel hole 11 Channel recess 12 Fixed electrode 13 Space 14 Bonding layer 15 Inlet 20 Micro valve 21 Valve seat substrate 22 Back plate 23 Valve body forming substrate 24 Valve body 25 Beam 26 Inlet 27 Outlet 28 Electrostatic gap 29 Valve body forming substrate side electrode 30 Valve seat substrate side electrode 31 Insulating film 32 Protrusion 33 Valve seat substrate gap 34 Back plate gap 35 Air groove 36 Driving voltage source 37 Fluid flow 38 Tube 39 Nut 40 Body 41 Ferrule 42 Electrode extraction hole 43 Thermal flow meter

Claims (5)

A valve body is provided to face the valve seat substrate, and the valve body is displaced by electrostatic attraction between an electrode provided on the valve body and an electrode provided on the valve seat substrate, and provided on the valve seat substrate. In the microvalve that controls the inflow of the inlet that allows the fluid to flow in,
A back plate provided on the opposite side of the valve seat substrate across the valve body;
A lead-out port that is provided in the back plate and flows out the fluid;
A protrusion provided on the valve seat substrate and surrounding the introduction port;
A microvalve having an insulating film provided on the valve body so as to face the protrusion.   The micro valve according to claim 1, wherein the outlet port is provided with a groove for leading the fluid even when the valve body is pressed against the back plate.   The microvalve according to claim 1, wherein the protrusion is circular.   The microvalve according to claim 1, wherein the valve body forming substrate and the valve body are supported through a beam and are integrally formed.   The microvalve according to claim 4, wherein the valve body forming substrate, the valve body, and the beam are made of silicon.

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