US20120051946A1

US20120051946A1 - Micropump and driving method thereof

Info

Publication number: US20120051946A1
Application number: US13/197,886
Authority: US
Inventors: Sang Joon Lee; Boheum Kim
Original assignee: Academy Industry Foundation of POSTECH
Current assignee: Academy Industry Foundation of POSTECH
Priority date: 2010-01-20
Filing date: 2011-08-04
Publication date: 2012-03-01
Also published as: KR101142430B1; KR20110085849A

Abstract

Provided are a micropump that makes it possible to reduce the entire size and improve pumping performance of fluid, and a method of operating the micropump. The micropump includes a case that forms a first space and a second space that are connected through a connection channel, a fluid intake pipe that is connected to the first space, a fluid discharge pipe that is connected to the second space, a first deforming member that is disposed on the case to cover the first space, and a second deforming member that is disposed on the case to cover the second space. The second deforming member is formed larger than the first deforming member and the maximum displacement of the second deforming member is larger than the maximum displacement of the first deforming member.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2010-0082546 filed in the Korean Intellectual Property Office on Aug. 25, 2010, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention
The present invention relates to a micropump for delivering fluid. More particularly, the present invention relates to a micropump that sucks fluid by generating a strong suction force in a channel and delivers the sucked fluid to the downstream, and a driving method thereof.
(b) Description of the Related Art
With the development in the micromachining technology, researches on microdevices, such as MEMS (Micro-Electro Mechanical System), have been actively conducted. In the devices, a micropump, a device that manipulates a very small amount of fluid, using fluid mechanics, is applied to various fields, including medical chemistry systems and medical equipment, such as chemical analyzing systems and medicine delivery systems, and inkjet heads.
The micropump may be implemented by a piezoelectric micropump using a piezoelectric actuator. A typical piezoelectric micropump has a configuration in which three or more piezoelectric actuators are disposed in parallel in one pump case and electrically connected to a control device.
According to the piezoelectric micropump, when an electromotive force is applied to the piezoelectric actuators from the control device, the piezoelectric actuators sequentially operate and make a pumping action that sucks and discharges fluid. The micropump equipped with a plurality of piezoelectric actuators, as described above, can easily control the flow of fluid, but has a defect in that the pumping performance is low and the size is large.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide a micropump that can improve pumping performance while decreasing the entire size, and a driving method thereof.
An exemplary embodiment of the present invention provides a micropump including: a case that forms a first space and a second space that are connected through a connection channel; a fluid intake pipe that is positioned at a side of the case and connected to the first space; a fluid discharge pipe that is positioned at the other side of the case and connected to the second space; a first deforming member that is disposed on the case to cover the first space and deforms in response to an electric signal; and a second deforming member that is disposed on the case to cover the second space and deforms in response to an electric signal. The second deforming member is formed larger than the first deforming member and the maximum displacement of the second deforming member is larger than the maximum displacement of the first deforming member.
The first deforming member and the second deforming member may be implemented by piezoelectric actuators. The first deforming plate may include a first conductive elastic plate and a first piezoelectric device and the second deforming member may include a second conductive elastic plate and a second piezoelectric device.
The micropump may further include: a plurality of lead wires that is connected to the first conductive elastic plate, the first piezoelectric device, the second conductive elastic plate, and the second piezoelectric device, respectively; and a controller that is electrically connected with the plurality of lead wires.
On the other hand, the first deforming member and the second deforming member may be made of artificial muscles. The first deforming member may include a first imitative muscle and a first electrode and the second deforming member may include a second imitative muscle and a second electrode.
The first imitative muscle and the second imitative muscle may include nanofiber made of electric active hydrogel. The micropump may include: a pair of lead wires that is connected to the first electrode and the second electrode, respectively; and a controller that is electrically connected with the pair of lead wires.
The volume of the second space may be larger than the volume of the first space.
The micropump may further include: an on/off valve that is disposed in the connection channel; and an anti-backflow member that is disposed in the fluid intake pipe and the fluid discharge pipe. On the other hand, the micropump may further include an anti-backflow member disposed in the fluid intake pipe, the connection channel, and the fluid discharge pipe.
The on/off valve may be a piezoelectric valve that includes a first piezoelectric disk and a second piezoelectric disk that are disposed in parallel with the connection channel.
The anti-backflow member may be formed in a cone shape of which the inner diameter gradually increases from a side facing the fluid intake pipe to the opposite side facing the fluid discharge pipe.
On the other hand, the anti-backflow member may include: a deforming plate that is formed of a thin layer and has a fixed end and a free end; and a fixing protrusion that is positioned ahead of the free end of the deforming plate in a forward direction toward the fluid discharge pipe from the fluid intake pipe.
Another exemplary embodiment of the present invention provides a method of operating a micropump, including: a first section where the first deforming member expands from the minimum displacement to the maximum displacement and the second deforming member initially expands from the minimum displacement; a second section where the first deforming member retracts from the maximum displacement and the second deforming member expands to the maximum displacement; and a third section where the first deforming member retracts to the minimum displacement and the second deforming member retracts from the maximum displacement.
The second deforming member may start to expand from the minimum displacement with a time difference from the maximum displacement position of the first deforming member in the first section. The minimum displacement position of the first deforming member may have a time difference from the maximum displacement position of the second deforming member in the third section.
Yet another exemplary embodiment of the present invention provides a method of operating a micropump, including: a first section where the first deforming member expands from the minimum displacement to the maximum displacement and the second deforming member initially expands from the minimum displacement; a second section where the first deforming member retracts from the maximum displacement to the minimum displacement and the second deforming member expands to the maximum displacement; and a third section where the first deforming member initially expands from the minimum displacement and the second deforming member retracts to the minimum displacement.
The second deforming member may start to expand from the minimum displacement with a time difference from the maximum displacement position of the first deforming member in the first section. The minimum displacement position of the first deforming member may agree with the maximum displacement position of the second deforming member in the second section.
Still another exemplary embodiment of the present invention a method of operating a micropump, including: a first section where fluid is sucked into the first space by expanding the first deforming member from the minimum displacement to the maximum displacement; a second section where fluid is sucked into the first space and the second space by retracting the first deforming member from the maximum displacement to the minimum displacement and expanding the second deforming member from the minimum displacement to the maximum displacement; and a third section where the fluid in the first space and the second space is discharged by retracting the second deforming member from the maximum displacement to the minimum displacement.
The maximum displacement position of the first deforming member may agree with the minimum displacement position of the second deforming member.
In all of the methods of operating a micropump, the on/off valve may be positioned in the connection channel of the micropump and the on/off valve may open the connection channel by operating simultaneously with the expansion of the second deforming member and may close the connection channel by operation simultaneously with that the second deforming member reaches the maximum displacement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a micropump according to a first exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of the micropump according to the first exemplary embodiment of the present invention.

FIG. 3 is a schematic diagram showing an on/off valve in the micropump shown in FIG. 1.

FIG. 4 is a schematic diagram showing an exemplary variation of an anti-backflow member in the micropump shown in FIG. 1.

FIG. 5 is a cross-sectional view of a micropump according to a second exemplary embodiment of the present invention.

FIG. 6 is a cross-sectional view of a micropump according to a third exemplary embodiment of the present invention.

FIG. 7 is a cross-sectional view of a micropump according to a fourth exemplary embodiment of the present invention.

FIG. 8 is a waveform diagram showing applied signals of a first deforming member and a second deforming member shown to illustrate a first operation method of a micropump.

FIG. 9 is a waveform diagram showing applied signals of a first deforming member and a second deforming member shown to illustrate a second operation method of a micropump.

FIG. 10 is a waveform diagram showing applied signals of a first deforming member and a second deforming member shown to illustrate a third operation method of a micropump.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.
FIG. 1 and FIG. 2 are a plan view and a cross-sectional view of a micropump according to a first exemplary embodiment of the present invention.
Referring to FIG. 1 and FIG. 2, a micropump 100 according to the first exemplary embodiment includes a case 10, a fluid intake pipe 12, a fluid discharge pipe 14, a first deforming member 16, a second deforming member 18 and a controller 20.
The case 10 has a first space 101, a connection channel 103, and a second space 102, sequentially formed in one direction therein. The first space 101 and the second space 102 are separately positioned at a predetermined distance from each other and the connection channel 103 smaller in size than the two spaces 101 and 102 is formed between the two spaces 102 and 103 and connects the two spaces 101 and 102.
The fluid intake pipe 12 is fixed to a side of the case 10 that is in contact with the first space 101 and connected with the first space 101. The fluid discharge pipe 14 is fixed to the other side of the case 10 that is in contact with the second space 102 and connected with the second space 102. FIG. 1 and FIG. 2 show when the fluid intake pipe 12 is positioned at the left of the case 10 and the fluid discharge pipe 14 is positioned at the right of the case 10, as an example.
The first deforming member 16 is disposed on the case 10 to cover the first space 101 and the second deforming member 102 is disposed on the case 10 to cover the second space 102. The first deforming member 16 and the second deforming member 18 are positioned at a predetermined distance from each other. In the exemplary embodiment, the first deforming member 16 and the second deforming member 18 are implemented by piezoelectric actuators.
The first deforming member 16 has a stacking structure composed of a first conductive elastic plate 161 and a first piezoelectric element 162 while the second deforming member 18 has a stacking structure composed of a second conductive elastic plate 181 and a second piezoelectric element 182. A lead wire 22 is connected to the first conductive elastic plate 161, the first piezoelectric element 162, the second conductive elastic plate 181, and the second piezoelectric element 182, respectively, and the lead wires 22 are connected to the controller 20.
The first deforming member 16 and the second deforming member 18 make an expanding or retracting displacement in accordance with the polarity when an electromotive force is applied from the controller 20. The maximum displacement (second displacement) of the second deforming member 18 close to the fluid discharge pipe 14 is larger than the maximum displacement (first displacement) of the first deforming member 16 close to the fluid intake pipe 12. As a result, the second deforming member 18 generates a pressure inclination larger than the first deforming member 16, such that it is possible to effectively control the flow of fluid in the operation process of the micropump 100, which is described below.
The second deforming member 18 is formed larger than the first deforming member 16 to increase the maximum displacement of the second deforming member 18. That is, the second conductive elastic plate 181 is formed larger than the first conductive elastic plate 161 and the second piezoelectric device 182 is formed larger than the first piezoelectric device 162. Further, the volume of the second space 102 that is in contact with the second deforming member 18 is defined larger than the volume of the first space 101 that is in contact with the first deforming member 16.
Further, the micropump 100 includes an on/off valve 24 disposed in the connection channel 103 and an anti-backflow member 26 disposed in the fluid discharge pipe 14. The anti-backflow member 26 may also be disposed in the fluid intake pipe 12. The on/off valve 24 is an active valve and opens or closes the connection channel 103 while the operation is controlled by the controller 20. The on/off valve 24 may be implemented by a common mechanical valve or a piezoelectric valve using a piezoelectric device.
FIG. 3 is a schematic diagram showing an on/off valve in the mircropump shown in FIG. 1.
Referring to FIG. 3, the piezoelectric valve 240 includes a first piezoelectric disk 241 and a second piezoelectric disk 242 that are disposed in parallel with the connection channel 103. The first piezoelectric disk 241 may have a stacking structure of a conductive elastic plate and a piezoelectric device and the second piezoelectric disk 242 may also have a stacking structure of a conductive elastic plate and a piezoelectric device. The first piezoelectric disk 241 and the second piezoelectric disk 242 are connected with the controller 20 through the lead wires 243, respectively.
The first piezoelectric disk 242 and the second piezoelectric disk 242 close the connection channel 103 by coming in contact with each other when an electromotive force is not applied from the controller 20, and opens the connection channel 103 by expanding away from each other when an electromotive force is applied from the controller 20. The piezoelectric valve 240 can open/close the connection channel 103 fast by these operations.
As shown in FIG. 3, the piezoelectric valve 240 is shown to described an example of the on/off valve 24, and the on/off valve 24 of the present invention is not limited to the piezoelectric valve 240 and all valves that can open/close the connection channel 103 can be used.
Referring to FIG. 1 and FIG. 2, the anti-backflow member 26 is a passive valve, which allows the fluid to smoothly flow in the forward direction toward the fluid discharge pipe 14 from the fluid intake pipe 12, while preventing the fluid from flowing in the opposite direction.
The anti-backflow member 26 may be formed in a cone shape of which the inner diameter gradually increases from a side facing the fluid intake pipe 12 to the opposite side facing the fluid discharge pipe 14. In this case, the fluid cannot pass through the anti-backflow member 26 by pressure that increases when flowing in the backward direction, such that the anti-backflow member 26 can effectively stop the backward flow of the fluid.
FIG. 4 is a schematic diagram showing an exemplary variation of an anti-backflow member in the micropump shown in FIG. 1.
Referring to FIG. 4, the anti-backflow member 260 may have a structure composed of a deforming plate 28 and a fixing protrusion 30, instead of the cone shape. The deforming plate 28 may be made of a thin layer that can easily deform. The deforming plate 28 has a fixed end 281 that is partially fixed in the fluid intake pipe 12 and the fluid discharge pipe 14 and a free end 282 that is separated, not fixed, at the other portion. Further, the fixing protrusion 30 is positioned ahead of the free end 282 of the deforming plate 28 in the forward direction toward the fluid discharge pipe 14 from the fluid intake pipe 12.
Accordingly, the anti-backflow member 260 opens the channel while the free end 282 of the deforming plate 28 moves away from the fixing protrusion 30 when the fluid flows in the forward direction, whereas it closes the channel while the free end 282 of the deforming plate 28 is blocked by the fixing protrusion 30 when the fluid flows in the backward direction. As a result, the anti-backflow member 260 can effectively stop the backward flow of the fluid.
Referring to FIG. 1 and FIG. 2, the micropump 100 according to the first exemplary embodiment can effectively control the fluid flow even being equipped with the two deforming members 16 and 18 by setting the maximum displacement of the second deforming member 18 larger than the maximum displacement of the first deforming member 16. Therefore, it is possible to reduce the size of the micropump 100 by decreasing the number of deforming members 16 and 18.
Further, the micropump 100 according to the first exemplary embodiment can pump fast the viscous fluid in the forward direction by using the on/off valve 24 and the anti-backflow member 26, in addition to the first and second deforming members 16 and 18, such that pumping performance can be improved.
FIG. 5 is a cross-sectional view of a micropump according to a second exemplary embodiment of the present invention.
Referring to FIG. 5, a micropump 200 according to the second exemplary embodiment has the same configuration as the micropump 100 of the first exemplary embodiment, except that the anti-backflow member 26 is disposed in the connection channel 103. The same members as those in the first exemplary embodiment are indicated by the same reference numerals.
The micropump 200 according to the second exemplary embodiment is not provided with an on/off valve, and an anti-backflow member 26 is disposed in a connection channel 103 and a fluid discharge pipe 14. The anti-backflow member 26 may also be disposed in a fluid intake pipe 12.
The anti-backflow member 26 may be formed in a cone shape of which the inner diameter gradually increases from a side facing the fluid intake pipe 12 to the opposite side facing the fluid discharge pipe 14. On the other hand, as shown in FIG. 4, the anti-backflow member 260 may have a structure composed of a deforming plate 28 and a fixing protrusion 30.
FIG. 6 is a cross-sectional view of a micropump according to a third exemplary embodiment of the present invention.
Referring to FIG. 6, a micropump 300 according to the third exemplary embodiment has the same configuration as the micropump 100 according to the first exemplary embodiment, except that a first deforming member 160 and a second deforming member 180 are made of artificial muscles. The same members as those in the first exemplary embodiment are indicated by the same reference numerals.
The first deforming member 160 is composed of a first imitative muscle 163 and a first electrode 164 and the first electrode 164 is electrically connected with a controller 20 through the corresponding lead wire 22. The second deforming member 180 is composed of a second imitative muscle 183 and a second electrode 184 and the second electrode 184 is electrically connected with a controller 20 through the corresponding lead wire 22. The second imitative muscle 183 is formed larger than the first imitative muscle 163 such that the maximum displacement of the second deforming member 180 is larger than the maximum displacement of the first deforming member 160.
The first and the second imitative muscles 163 and 183 may be made of nanofiber that can react to electric stimulation, and are physically retracted or expanded by electric stimulation received through the first and the second electrodes 164 and 184. The first and the second imitative muscles 163 and 183 may be manufactured by composing nanofiber with electric active hydrogel. The material and manufacturing method of the first and the second imitative muscles 163 and 183 are not limited to the exemplary embodiment and may be variously changed.
FIG. 7 is a cross-sectional view of a micropump according to a fourth exemplary embodiment of the present invention.
Referring to FIG. 7, a micropump 400 according to the fourth exemplary embodiment has the same configuration as the micropump 200 according to the second exemplary embodiment, except that the first deforming member 160 and the second deforming member 180 are made of artificial muscles. The same members as those in the second exemplary embodiment are indicated by the same reference numerals. The configurations of the first deforming member 160 and the second deforming member 180 are the same as those in the third exemplary embodiment, such that the detailed description is not provided.
FIG. 8 is a waveform diagram showing applied signals of a first deforming member and a second deforming member shown to illustrate a first operation method of the micropumps according to the first to fourth exemplary embodiments. One cycle waveform is shown in (a) of FIG. 8 and a continuous waveform is shown in (b) of FIG. 8. In (a) of FIG. 8, the vertical axis shows the displacement of the first deforming member and the second deforming member, which shows the amount of maximum upward displacement, assuming that the flat state is 0.
Referring to FIG. 8, the operation method of the micropump includes a first section, a second section, and a third section. The first section is a section where an electric signal is applied to the first deforming member such that the first deforming member expands to the maximum displacement (first displacement) while an electric signal is applied to the second deforming member, with a time difference from the first deforming member, such that the second deforming member initially expands. The second section is a section where the first deforming member retracts from the maximum displacement while the second deforming member expands to the maximum displacement (second displacement). The third section is a section where the first deforming member retracts to the minimum displacement while the second deforming member retracts.
Referring to FIG. 2 and FIG. 8, the first deforming member 16 expands from the minimum displacement to the maximum displacement in the first section. Therefore, an intake force is generated in the first space 101 and the fluid is sucked from the first intake pipe 12 into the first space 101. In the exemplary embodiment, the minimum displacement implies zero displacement.
In the first section, the second deforming member 18 starts to expand from the minimum displacement with a time difference “a” shown in FIG. 8, before the first deforming member 16 reaches the maximum displacement. Accordingly, the fluid in the first space 101 can be sucked into the second space 102 when the fluid in the first space 101 keeps the inertia in the forward direction, by opening the second space 102, such that energy efficiency of the micropump 100 can be increased.
In the second section, the first deforming member 16 starts to retracts from the maximum displacement and the second deforming member 18 expands to the maximum displacement. Accordingly, the maximum intake force is generated in the second space 102, such that the fluid is sucked into the second space 102 through the first space 101 and the connection channel 103. Since the maximum displacement of the second deforming member 18 is larger than the maximum displacement of the first deforming member 16, the second deforming member 18 makes a pressure inclination larger than the first deforming member 16.
In the third section, the first deforming member 16 retracts to the minimum displacement and the second deforming member 18 also retracts. The minimum displacement of the second deforming member 18 may exists in the first section of the next cycle. As the first deforming member 16 and the second deforming member 18 retract, the fluid in the first space 101 and the second space 102 is discharged to the fluid discharge pipe 14. The first deforming member 16 has a function of preventing backward discharge through the fluid intake pipe 12, when the first deforming member 16 keeps the minimum displacement in the third section.
When the on/off valve 24 is disposed in the connection channel 103, the on/off valve 24 opens the connection channel 103 by operating simultaneously with the expansion of the second deforming member 18 in the first section. Further, the on/off valve 24 closes the connection channel 103 by operating simultaneously with that the second deforming member 18 reaches the maximum displacement between the second section and the third section.
The on/off valve 24 actively controls the time when the fluid flows into the second space 102 from the first space 101. In particular, when the on/off valve 24 is implemented by the piezoelectric valve 240, as shown in FIG. 3, the piezoelectric valve 240 has a structure than can expand by itself, such that the piezoelectric valve 240 can contribute to increasing the pumping performance and the energy efficiency of the micropump 100 by generating an intake force by itself.
Further, the anti-backflow member 26 disposed in the fluid intake pipe 12 and the fluid discharge pipe 14 prevents backward flow of the fluid in the operation of the micropump 100.
As described above, the first, second, and third sections constitute one pumping cycle while the second deforming member 18 makes a displacement larger than the first deforming member 16 and accordingly makes a pressure inclination larger than the first deforming member 16. Therefore, the micropump 100 according to the present exemplary embodiment can effectively send the fluid in the forward direction from the fluid intake pipe 12 to the fluid discharge pipe 14 by increasing the pumping performance, and it is possible to reduce the entire size by decreasing the number of deforming members 16 and 18.
In the operation method of the micropump shown in FIG. 8, the maximum displacement position of the second deforming member 18 and the minimum displacement position of the first deforming member 16 do not agree with each other. That is, the second deforming member 18 expands to the maximum displacement and then the first deforming member 16 retracts to the minimum displacement. Further, a time difference as much as the second section is maintained between the maximum displacement position of the first deforming member 16 and the maximum displacement position of the second deforming member 18.
FIG. 9 is a waveform diagram showing applied signals of a first deforming member and a second deforming member shown to illustrate a second operation method of the micropumps according to the first exemplary embodiment to the fourth exemplary embodiment. One cycle waveform is shown in (a) of FIG. 9 and a continuous waveform is shown in (b) of FIG. 9.
Referring to FIG. 9, the operation method of the micropump includes a first section, a second section, and a third section. The first section is a section where an electric signal is applied to the first deforming member such that the first deforming member expands to the maximum displacement (first displacement) while an electric signal is applied to the second deforming member, with a time difference from the first deforming member, such that the second deforming member initially expands. The second section is a section where the first deforming member retracts from the maximum displacement to the minimum displacement while the second deforming member expands to the maximum displacement (second displacement). The third section is a section where the first deforming member initially expands from the minimum displacement while the second deforming member retracts to the minimum displacement.
The second operation method of the micropump includes the same processes as those in the first operation method, except that the minimum displacement position of the first deforming member agrees with the maximum displacement position of the second deforming member and the first deforming member initially expands in the third section.
As described above, as the minimum displacement position of the first deforming member agrees with the maximum displacement position of the second deforming member, the first deforming member completely functions as a valve when the second deforming member retracts in the third section, such that it is possible to prevent the backward flow of the fluid and increase the pumping performance. Further, according to the second operation method, the flow rate from the first deforming member to the second deforming member is larger than that in the first operation method, such that it is possible to increase the available flow rate of the micropump without increasing the size of the micropump.
FIG. 10 is a waveform diagram showing applied signals of a first deforming member and a second deforming member shown to illustrate a third operation method of the micropumps according to the first exemplary embodiment to the fourth exemplary embodiment. One cycle waveform is shown in (a) of FIG. 10 and a continuous waveform is shown in (b) of FIG. 10.
Referring to FIG. 10, the operation method of the micropump includes a first section, a second section, and a third section. The first section is a section where an electric signal is applied to the first deforming member such that the first deforming member expands to the maximum displacement (first displacement). The second section is a section where the first deforming member retracts from the maximum displacement to the minimum displacement while an electric signal is applied to the second deforming member such that the second deforming member expands to the maximum displacement (second displacement). The third section is a section where the first deforming member is maintained at the minimum displacement while the second deformation member retracts to the minimum displacement.
The third operation method of the micropump includes the same processes as those in the second operation method except that the maximum displacement position of the first deforming member agrees with the minimum displacement position of the second deforming member.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

What is claimed is:

1. A micropump comprising:

a case that forms a first space and a second space that are connected through a connection channel;

a fluid intake pipe that is positioned at a side of the case and connected with the first space;

a fluid discharge pipe that is positioned at the other side of the case and connected with the second space;

a first deforming member that is disposed on the case to cover the first space and deformed by an electric signal; and

a second deforming member that is disposed on the case to cover the second space and deformed by an electric signal,

wherein the second deforming member is formed larger than the first deforming member, and

the maximum displacement of the second deforming member is larger than the maximum displacement of the first deforming member.

2. The micrcopump of claim 1, wherein:

the first deforming member and the second deforming member are implemented by piezoelectric actuators.

3. The micropump of claim 2, wherein:

the first deforming plate includes a first conductive elastic plate and a first piezoelectric device, and

the second deforming member includes a second conductive elastic plate and a second piezoelectric device.

4. The micropump of claim 3, further comprising:

a plurality of lead wires that is connected to the first conductive elastic plate, the first piezoelectric device, the second conductive elastic plate, and the second piezoelectric device, respectively; and

a controller that is electrically connected with the plurality of lead wires.

5. The micropump of claim 1, wherein:

the first deforming member and the second deforming member are made of artificial muscles.

6. The micropump of claim 5, wherein:

the first deforming member includes a first imitative muscle and a first electrode, and

the second deforming member includes a second imitative muscle and a second electrode.

7. The micropump of claim 6, wherein:

the first imitative muscle and the second imitative muscle include nanofiber made of electric active hydrogel.

8. The micropump of claim 6, further comprising:

a pair of lead wires that is connected to the first electrode and the second electrode, respectively; and

a controller that is electrically connected with the pair of lead wires.

9. The micropump of claim 1, wherein:

the volume of the second space is larger than the volume of the first space.

10. The micropump of claim 1, further comprising:

an on/off valve that is disposed in the connection channel; and

an anti-backflow member that is disposed in the fluid intake pipe and the fluid discharge pipe.

11. The micropump of claim 10, wherein:

the on/off valve is a piezoelectric valve that includes a first piezoelectric disk and a second piezoelectric disk that are disposed in parallel with the connection channel.

12. The micropump of claim 10, wherein:

the anti-backflow member is formed in a cone shape of which the inner diameter gradually increases from a side facing the fluid intake pipe to the opposite side facing the fluid discharge pipe.

13. The micropump of claim 10, wherein:

the anti-backflow member includes:

a deforming plate that is formed of a thin layer and has a fixed end and a free end; and

a fixing protrusion that is positioned ahead of the free end of the deforming plate in a forward direction toward the fluid discharge pipe from the fluid intake pipe.

14. The micropump of claim 1, further comprising:

an anti-backflow member that is disposed in the fluid intake pipe, the connection channel, and the fluid discharge pipe.

15. The micropump of claim 14, wherein:

16. The micropump of claim 14, wherein:

the anti-backflow member includes:

17. A method of operating the micropump of claim 1, comprising:

a first section where the first deforming member expands from the minimum displacement to the maximum displacement and the second deforming member initially expands from the minimum displacement;

a second section where the first deforming member retracts from the maximum displacement and the second deforming member expands to the maximum displacement; and

a third section where the first deforming member retracts to the minimum displacement and the second deforming member retracts from the maximum displacement.

18. The method of claim 17, wherein:

the second deforming member starts to expand from the minimum displacement with a time difference from the maximum displacement position of the first deforming member in the first section.

19. The method of claim 17, wherein:

the minimum displacement position of the first deforming member has a time difference from the maximum displacement position of the second deforming member in the third section.

20. The method of claim 17, wherein:

an on/off valve is disposed in a connection channel of the micropump, and

the on/off valve opens the connection channel by operating simultaneously with the expansion of the second deforming member and closes the connection channel by operating simultaneously with that the second deforming member reaches the maximum displacement.

21. A method of operating the micropump of claim 1, comprising:

a second section where the first deforming member retracts from the maximum displacement to the minimum displacement and the second deforming member expands to the maximum displacement; and

a third section where the first deforming member initially expands from the minimum displacement and the second deforming member retracts to the minimum displacement.

22. The method of claim 21, wherein:

23. The method of claim 21, wherein:

the maximum displacement position of the first deforming member agrees with the maximum displacement position of the second deforming member in the second section.

24. The method of claim 21, wherein:

an on/off valve is disposed in a connection channel of the micropump, and

25. A method of operating the micropump of claim 1, comprising:

a first section where fluid is sucked into the first space by expanding the first deforming member from the minimum displacement to the maximum displacement;

a second section where fluid is sucked into the first space and the second space by retracting the first deforming member from the maximum displacement to the minimum displacement and expanding the second deforming member from the minimum displacement to the maximum displacement; and

a third section where the fluid in the first space and the second space is discharged by retracting the second deforming member from the maximum displacement to the minimum displacement.

26. The method of claim 25, wherein:

the maximum displacement position of the first deforming member agrees with the minimum displacement position of the second deforming member.

27. The method of claim 25, wherein:

an on/off valve is disposed in a connection channel of the micropump, and