JP2001317647A - Micro-valve and micro-pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a micro-valve and a micro-pump allowing washing and partial exchange easily when a foreign matter is mixed and partial malfunction occurs. SOLUTION: A substrate for cover 2 having a substrate for actuator 1 which is driven actually, a valve part 11, and a pumping part 12 is detachable to enable washing easily by removing the substrate for cover 2 when foreign matter is mixed. Furthermore, if malfunction occurs in the valve part 11 and the pumping part 12, the substrate for cover 2 only can be exchanged easily. Moreover, when design such as internal volume and a shutting-off force of a valve is changed, only the substrate for cover 2 is exchanged, and the substrate for actuator 1 can be used in common.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro-valve or a micro-pump which is used in a medical field or an analytical field and performs a small and highly accurate fluid control.

[0002]

2. Description of the Related Art Conventionally, as a pump which performs fluid control with high accuracy and small size, for example, Japanese Patent Application Laid-Open No. 4-66784 shown in FIG.
There is a pump described in the issue. This is two valves 15
Due to the positional relationship between the fluid inlet / outlet 4 and the fluid inlet / outlet 4, each has a structure that functions as a one-way valve. Therefore, a voltage is applied to the piezoelectric element 6 at the center to generate a change in the volume inside the pump, thereby achieving one-way liquid transfer. The glass substrate 13 and the silicon substrate 14 are joined by anodic bonding.

In the case of a micropump described in Japanese Patent Application Laid-Open No. Hei 5-1669 in FIG. 3, a thin film of metal or polysilicon 16 is formed on a sacrificial layer of an oxide film on a silicon substrate 14 and further etched. By removing the sacrificial layer, a check valve made of metal or polysilicon is formed, and a pump is formed by the piezoelectric element 6 provided on the glass substrate 13.

[0004]

The conventional microvalves and micropumps have several problems. In the case of the micropump shown in FIGS. 2 and 3, both layers could not be removed because each layer was firmly joined by a technique such as anodic bonding. For this reason, when a problem occurs, the entire device must be replaced, and there is a problem that the cost is increased. Further, when foreign matter enters the inside, there is a problem that it is very difficult to remove the foreign matter. Also, it has been difficult to change the performance such as the internal volume and the shutoff force of the valve.

[0005]

In the microvalve and the micropump according to the present invention, an actuator substrate for deforming a diaphragm by an actuator and a cover substrate having a valve section, a pumping section, a flow path section and the like are pressure-bonded. The structure is fixed by For this reason, these substrates can be freely attached and detached, and the interior can be cleaned by removing the actuator substrate and the cover substrate when foreign matter is mixed. Also, when changing the volume or shape of the valve portion or the pumping portion, only the cover substrate needs to be replaced, and the actuator substrate can be commonly used.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. [Embodiment 1] In this embodiment, an example of a microvalve in which a silicon substrate is used as a substrate for an actuator and a silicone resin is used as a substrate for a cover will be described.

FIG. 4 is an exploded view of the present microvalve.
The microvalve is composed of an actuator substrate 1 made of a silicon substrate and a cover substrate 2 made of a silicone resin, and these two substrates are fixed in close contact with each other.

First, the cover substrate 2 will be described. The cover substrate 2 has a concave portion, and the concave portion has a structure separated by a separator 3.
Each of the recesses divided into two by the separator 3 has a through-hole formed so as to penetrate the cover substrate 2, and the through-hole becomes a fluid port 4 connecting the inside and the outside of the microvalve. The shape of the concave portion is not particularly limited, and a circular concave portion as shown in FIG. 5 may be used. There is no particular limitation on the position of the fluid port,
As shown in FIG. 6, it is also possible to use a structure in which the flow path 7 serves as a fluid inlet / outlet as it is. The cover substrate 2 can be formed into an arbitrary shape by preparing a mold using a photolithography technique, pouring an uncured silicone resin into the mold, and then curing the resin.

Next, the actuator substrate 1 will be described. In this embodiment, first, the silicon substrate
Perform anisotropic etching with KOH. This etching is performed from the back surface of the silicon substrate, and is continued until the diaphragm 5 having a desired thickness is formed. However, the surface of the silicon substrate is kept flat without etching. However, the size of the diaphragm 5 is not limited to the concave portion (including the separator) in the cover substrate 2.
Should be less than or equal to The reason why the sizes of the two are set in this manner will be described later.
In addition, when anisotropic etching of silicon is used, the shape of the diaphragm is square, but if isotropic etching such as reactive ion etching is used, a diaphragm having a shape other than square can be formed. . A piezoelectric element 6 is adhered from the back surface to the diaphragm 5 formed by etching.
The piezoelectric element 6 has a unimorph structure. By applying a voltage to the piezoelectric element 6, the diaphragm 5 can be deformed. The deformation of the diaphragm can be realized by various actuators using electrostatic force, magnetic force, air pressure, shape memory alloy, and the like, and is not limited to the piezoelectric element. There is no limitation on the method of forming the diaphragm, and the material of the actuator substrate is not limited to silicon.

The above-mentioned cover substrate 2 and actuator substrate 1 are pressure-bonded in such a manner that the surface of the cover substrate 2 where the concave portion exists and the non-etched surface of the actuator substrate 1 are in contact with each other ( (FIG. 7).
At this time, the two substrates are positioned so that the center of the concave portion of the cover substrate 1 and the diaphragm 5 of the actuator substrate 1 coincide with each other. PD on cover substrate 2
If a highly adhesive silicone resin such as MS (polydimethylsiloxane) is used, and a silicon substrate having a high degree of flatness is used for the actuator substrate 1, a sufficient adhesion between the two can be achieved without physical fixing. Can be obtained. In this case, even if a pressure of about several kilopascals is applied from the fluid port 4, no fluid leaks from between the actuator substrate 1 and the cover substrate 2.

As shown in FIG. 8, there is also a method of fixing the actuator substrate 1 and the cover substrate 2 by sandwiching them by using the holder 8. Holder 8 is spacer 9
And is fixed by a screw 10. The pressing force between the actuator side substrate 1 and the cover substrate 2 can be adjusted by the thickness of the spacer 9. In this case, no leakage occurs between the two substrates even under a high pressure, as compared with the case where the substrates are simply brought into close contact with each other. Further, it is also possible to integrally form the conduit with the holder on the cover substrate 2 side. Since high adhesion can be obtained even between the holder 8 and the cover substrate, a leak-free conduit can be realized between the holder 8 and the microvalve body.

In any case, since the actuator substrate 1 and the cover substrate 2 are not particularly joined to each other, they have a structure that can be freely attached and detached. The material of the cover substrate 2 is not limited to silicone resin, and any material may be used as long as it has good adhesion to the actuator substrate 1 and is removable.

Further, even when the cover substrate and the actuator substrate are both formed of a substance having no adhesion, at least one of the contact surfaces of the cover substrate 1 and the actuator substrate 2 has an adhesive property. By forming a thin film of the above, it is also possible to provide a structure in which both can be detached and have high adhesion. Further, a structure in which a thermoplastic adhesive layer is used between the two substrates and the two substrates can be attached and detached by heating / cooling may be employed.

Alignment marks are provided on both substrates in order to repeat the positioning of both substrates with high accuracy. Also, by forming a guide on at least one of the substrates or the holder, highly accurate positioning can be repeatedly performed.

Next, the operation of the microvalve will be described. As already shown in FIG. 7, in the present microvalve, since the actuator substrate 1 and the cover substrate 2 are in close contact with each other, the separator 3 and the diaphragm 5 are also in close contact with each other. For this reason, when no voltage is applied to the piezoelectric element, the two fluid ports 4 are in a state of being cut off by the separator 3, so that even if pressure is applied from one of the fluid ports, no flow occurs. , And remain closed.

On the other hand, when a voltage is applied to the piezoelectric element 6, the diaphragm 5 bends due to the unimorph structure of the piezoelectric element 6 and the diaphragm 5, and the diaphragm 5 and the separator 3
There is a gap between them. By moving the fluid through this gap, a state where the valve is open is realized (FIG. 9). That is, the separator 3 functions as a kind of packing.

As described above, the present valve performs an operation of opening by applying a voltage and opening by stopping the application of the voltage. In addition, by reversing the direction of the voltage applied to the piezoelectric element, it is possible to press the diaphragm against the separator and more firmly close the microvalve.

Finally, the relationship between the size of the diaphragm and the recess will be described. As described above, the size of the diaphragm is equal to or smaller than the concave portion (including the separator) in the cover substrate. That is, the concave portion (including the separator) of the cover substrate covers the etched portion of the diaphragm. In this case, even if the diaphragm is deformed downward as already shown in FIG. 9, the periphery of the concave portion does not come off from the actuator substrate 1. Therefore, the fluid inside the microvalve does not leak outside from between the actuator substrate and the cover substrate.

Conversely, as shown in FIG.
Is larger than the concave portion of the cover substrate 2, when the diaphragm 5 is displaced downward, separation occurs between the diaphragm 5 and the cover substrate 2 at the periphery of the concave portion.
If pressure is applied from the fluid inlet / outlet 4 in this state, pressure is applied in a direction in which the actuator substrate 1 and the cover substrate 2 are peeled off, and therefore, there is a problem that fluid tends to leak from between the two substrates. Therefore, in the microvalve according to the present invention, the cover substrate 2 is moved from the diaphragm 5.
Is designed so that the concave portion at becomes large.

As described above, the microvalve according to the present invention has a structure in which the closed state is maintained when the microvalve is not driven when no voltage is applied. For this reason, even in a situation where there is a pressure difference between the fluid inlet side and the outlet side, the fluid can be held without consuming any energy. Further, when the cover substrate and the actuator substrate are fixed by the holder via the spacer, the pressure of the cover substrate and the actuator substrate can be adjusted by the thickness of the spacer. By doing so, it is possible to arbitrarily set the fluid holding force during non-driving.

The use of the holder in which the pipe is integrally formed also has the advantage that the preparation of the pipe in the microvalve is realized at the same time and the process is simplified. Since the holder and the substrate for the cover are also pressure-bonded, it is possible to form a pipeline without leakage.

Since the cover substrate and the actuator substrate are not bonded to each other, they can be freely attached and detached. Therefore, there is an advantage that the cover substrate can be removed when foreign matter enters the inside of the microvalve, and the inside can be easily cleaned. Further, when the separator is deteriorated due to repeated opening and closing of the valve, it is possible to replace only the cover substrate, and the actuator substrate can be used as it is. Since partial replacement is possible in this manner, the life of the entire microvalve can be extended.

It is also possible to change the cover substrate according to the characteristics required for the microvalve. When the present microvalve is opened by applying a voltage and the applied voltage is constant, the pressure-flow rate characteristic is determined by the width of the separator. Simply prepare multiple cover substrates with different separator widths and replace them as necessary,
A microvalve having different pressure-flow characteristics can be realized, and cost reduction can be realized. At the same time, it is possible to use the same electrical wiring and control system for the actuator, so that the versatility is increased. [Embodiment 2] In this embodiment, an example of a micropump using a silicon substrate as an actuator substrate and a silicone resin as a cover substrate will be described.

FIG. 1 is an exploded view of the present micropump.
The micro pump is a cover substrate 2 made of silicone resin.
And an actuator substrate 1 made of a silicon substrate, and these two substrates are fixed in close contact with each other.

First, the cover substrate 2 will be described. The cover substrate 2 has a valve portion 1 that operates on the same principle as the microvalve described in the first embodiment.
Two 1 are formed. One concave portion is formed in the middle of these valve portions 11 and functions as a pumping portion 12 for performing suction and discharge of a fluid. The two valve units 11 and the pump unit 12 have a structure connected by the flow path 7 and are arranged in series in the order of the valve unit-the pumping unit-the valve unit. Also,
A fluid port 4 is provided in each of the valve portions at both ends. FIG. 1 shows an example in which the width of the flow path 7 is narrower than the widths of the valve section 11 and the pumping section 12, but these may be the same width.

Next, the actuator substrate 1 made of a silicon substrate will be described. Three diaphragms 5 similar to those described in the first embodiment are formed on the silicon substrate, and a unimorph structure is formed by bonding the piezoelectric element 6. These diaphragms are used for the cover substrate 2.
Are arranged so as to correspond to the valve section 11 and the pumping section 12.

Actuator substrate 1 and cover substrate 2
Are adhered in the same manner as in the first embodiment. The processing method, shape, size, etc. of each element are all the same as those described in the first embodiment.

Next, the operation of the micropump according to the present embodiment will be described. Opening and closing of the two microvalves is as described in the first embodiment. As for the pumping section, the diaphragm is displaced by the unimorph structure of the diaphragm and the piezoelectric element, and the discharge and suction of the fluid are performed by the volume change. By driving these two microvalves and one pumping unit in a fixed sequence, liquid transfer from one fluid port to another fluid port is realized. Since such a micropump can arbitrarily open and close two valves and drive the pumping unit, it is possible to change the direction of liquid transfer by changing the drive order of the three actuators. Further, since the micropump uses the two microvalves described in Embodiment 1, the micropump has a structure in which a closed state is maintained without applying a voltage to the piezoelectric element. For this reason, even in a situation where there is a pressure difference between the fluid inlet side and the outlet side, the fluid can be held without consuming any energy.

Further, since the present micropump has a structure in which the cover substrate and the actuator substrate are not bonded, the two can be freely attached and detached. Therefore, there is an advantage that the cover substrate can be removed when foreign matter enters the inside of the micropump, and the inside can be easily cleaned. When the separator is deteriorated due to repeated opening and closing of the valve, it is possible to replace only the cover substrate, and the actuator substrate can be used as it is. Since partial replacement is possible in this way, the life of the entire micropump can be extended.

On the other hand, the cover substrate can be replaced according to the characteristics required for the micropump. For example, the characteristics of the microvalve can be changed by using the method described in Embodiment 1, and the characteristics at the time of suction or discharge can be changed by changing the depth or area of the concave portion of the pumping portion. It is. Micro pumps having different characteristics can be realized only by replacing the cover substrate, so that cost reduction is also realized. At the same time, the same thing can be used for the electric wiring and the control system of the actuator, so that the versatility is enhanced.

[0031]

The microvalve and the micropump according to the present invention have a structure in which the substrate for the actuator and the substrate for the cover are detachable, so that when foreign matter enters the inside, cleaning is performed by removing both. This has the effect of being possible. In addition, by preparing a plurality of cover portion substrates having different parameters and replacing them as necessary, a microvalve or a micropump having different characteristics can be easily realized. In this case, only the cover substrate needs to be replaced, and the actuator substrate can be used in common. Therefore, there is an advantage that the cost can be reduced. In addition, since the same thing can be used for the electric wiring and the control system of the actuator, the versatility is improved.

[Brief description of the drawings]

FIG. 1 is an exploded view showing an example of a micropump according to the present invention.

FIG. 2 is a cross-sectional view showing the structure of a conventional micropump.

FIG. 3 is an exploded view showing a structure of a conventional micropump.

FIG. 4 is an exploded view showing the structure of the microvalve of the present invention.

FIG. 5 shows an example of a cover substrate in the microvalve of the present invention.

FIG. 6 shows an example of a cover substrate in the microvalve of the present invention.

FIG. 7 is a sectional view showing the structure of the microvalve of the present invention.

FIG. 8 is a cross-sectional view showing a state in which a cover substrate and an actuator substrate are fixed by a holder.

FIG. 9 is a cross-sectional view showing a state where the microvalve of the present invention is open.

FIG. 10 is a cross-sectional view showing a state where the microvalve is opened when the diaphragm is larger than the concave portion in the cover substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Actuator board 2 Cover board 3 Separator 4 Fluid inlet / outlet 5 Diaphragm 6 Piezoelectric element 7 Flow path 8 Holder 9 Spacer 10 Screw 11 Valve part 12 Pumping part 13 Glass substrate 14 Silicon substrate 15 Valve 16 Polysilicon

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Ichikichi Furuta 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba F-term (reference) in Seiko Instruments Inc. 3H062 AA02 AA12 BB33 CC05 EE11 FF39 HH10 3H077 AA01 BB10 CC02 CC07 CC14 CC18 DD06 EE34 EE35 EE37 EE40 FF03 FF04 FF07 FF08 FF09 FF12 FF14 FF22 FF36 FF43 FF44 FF60

Claims (8)

[Claims] 1. A valve for controlling a fluid,
A substrate A having at least two fluid ports and a recess connected to the fluid ports and having the interior divided into at least two regions by a separator;
, A diaphragm, and a substrate B having an actuator that deforms the diaphragm. The substrate A and the substrate B are combined to form a flow path divided by a separator, and the substrate A and the substrate B In the state in which the diaphragms are combined, the deformed portion of the diaphragm is disposed immediately above the separator, and the outer periphery of the deformed portion of the diaphragm is inside the outer periphery of the concave portion of the substrate A, and the two do not cross each other A non-contact / contact state between the diaphragm and the separator is changed by the deformation of the diaphragm accompanying the driving of the actuator, and the opening and closing of the flow path is performed. A valve having a structure capable of easily and repeatedly bonding and separating the substrate B. 2. A structure that can easily and repeatedly bond and separate the substrate A and the substrate B, wherein at least one of the contact surfaces of the substrate A and the substrate B has an adhesive property, The valve according to claim 1, wherein the pressure is maintained at a level higher than the pressure of the fluid from the fluid port even if the bonding and separation of the substrate A and the substrate B are repeated. 3. The substrate having the adhesive structure according to claim 1,
Alternatively, any of the substrates B is made of an adhesive material, or at least one of the substrate A and the substrate B has a multilayer structure, and at least one of them is made of an adhesive material. 3. The valve according to claim 2, wherein the valve is configured. 4. A structure capable of repeatedly coupling and separating the substrate A and the substrate B, wherein the substrate A and the substrate B are mechanically coupled by a detachable holder provided outside the substrate A and the substrate B. The valve according to claim 1, characterized in that: 5. A pump for transferring a fluid, comprising: a substrate A having at least two fluid ports and a recess connected to the fluid ports and having an interior divided into at least three regions by a separator;
And at least two valve diaphragms; at least one pumping diaphragm; and a substrate B having an actuator that deforms the valve diaphragm and the pumping diaphragm. The substrate A and the substrate B are combined and divided by a separator. In a state where the substrate A and the substrate B are combined with each other, a deformed portion of the valve diaphragm is disposed immediately above the separator, and a deformation of the valve diaphragm and the pumping diaphragm is performed. All the outer peripheries of the portions are inside the outer perimeter of the concave portion of the substrate A, and the two do not cross each other,
And a structure in which the non-contact / contact state between the valve diaphragm and the separator changes due to the deformation of the valve diaphragm accompanying the driving of the actuator, thereby opening and closing the flow path. A pump having a structure for discharging and sucking a fluid by deformation of the pumping diaphragm, and a structure for easily and repeatedly coupling and separating the substrate A and the substrate B. 6. A structure which can easily and repeatedly bond and separate the substrate A and the substrate B, wherein at least one of the contact surfaces of the substrate A and the substrate B has adhesiveness, 6. The pump according to claim 5, wherein the pressure is maintained at a level higher than the pressure of the fluid from the fluid inlet / outlet port even when the bonding and separation of the substrate A and the substrate B are repeated. 7. The structure having the adhesive property, wherein the substrate A
Alternatively, one of the substrates B is made of an adhesive material, or at least one of the substrates A and B has a multilayer structure, and at least one of them is made of an adhesive material. 7. The pump according to claim 6, wherein the pump is operated. 8. A structure capable of repeatedly connecting and separating the substrate A and the substrate B is characterized in that the substrate A and the substrate B are mechanically connected by a detachable holder installed outside the substrate B. A pump according to claim 5, characterized in that: