KR100884893B1 - Micropump - Google Patents

Abstract

FIELD OF THE INVENTION The present invention relates to micropumps, and more particularly to valveless micropumps for flowing trace amounts of fluid. The micro-pump of the present invention includes a thin film, a piezoelectric element portion disposed on the upper surface of the thin film to deform and operate the thin film, a pump body forming a pumping chamber together with the thin film, and formed in the pump body and connected to one side of the pumping chamber. Inlet channels of length; And an outlet channel of a predetermined length formed in the pump body and connected to the other side of the pumping chamber, wherein the inlet channel gradually increases in cross-sectional area as it approaches the pumping chamber, and the outlet channel gradually increases in cross-sectional area as it moves away from the pumping chamber. Is increased. The pumping chamber is further provided with a vertical partition wall for dividing the chamber space. By such a configuration, efficient pumping is possible and leakage of fluid can be minimized.

Piezoelectric element, pumping chamber, inlet channel, outlet channel, valveless

Description

Micro Pump {MICROPUMP}

1 is a side cross-sectional view schematically showing a micropump of one embodiment according to the present invention;

2 is a front sectional view schematically showing a micropump of one embodiment according to the present invention;

3A and 3B are schematic views for explaining the operation of the micropump of the present invention.

4 is a side cross-sectional view schematically showing a micropump of one embodiment according to the present invention;

Figure 5 is a side cross-sectional view schematically showing another embodiment of the micropump according to the present invention.

6 is a side cross-sectional view schematically showing a micropump of another embodiment according to the present invention.

Figure 7 is a change in waveform with time of the drive voltage having a phase delay applied to the micropump of the present invention.

<Description of the symbols for the main parts of the drawings>

11 pump body 12 inlet channel

13 outlet channel 14 pumping chamber

15 thin film 16: vertical bulkhead

17: piezoelectric element portion 171: element region layer

171-1: first device region 171-2: second device region

172: upper electrode layer 172-1: first upper electrode layer

172-2: second upper electrode layer 173: lower electrode layer

FIELD OF THE INVENTION The present invention relates to micropumps, and more particularly to valveless micropumps for flowing trace amounts of fluid.

Prior art for micropumps for flowing or pumping trace amounts of fluid is disclosed in US Pat. No. 7,104,768. This prior art micropump comprises a pumping chamber and an inlet valve chamber and an outlet valve chamber, respectively, before and after the pumping chamber. Each chamber is composed of a thin film formed on the body and the upper portion, each piezoelectric element is attached to the upper portion of each thin film. In the conventional micro-pump, the piezoelectric element of the pumping chamber is pumped by deforming the thin film portion attached to the lower surface thereof, and the inlet and outlet chambers deform the thin film when the piezoelectric element is in operation to close the valve, The valve is open. However, this conventional micropump has a disadvantage in that the overall size of the pump increases because at least 3a piezoelectric elements are required. In addition, such a configuration is complicated in structure and manufacturing process. In addition, since the drive control of the three piezoelectric elements must be performed sequentially, the control of the drive signal is complicated. In addition, when the pump is not operating, the inlet and outlet valves are open, so there is a problem in that a relatively large amount of fluid leakage inside.

US Patent Application Publication No. 2005/0158188 discloses another prior art micropump. This technology has a check valve attached to the inlet and the outlet respectively. However, this technique is different in that it uses one piezoelectric element and there is no leakage of fluid, but there is a disadvantage in that a check valve must be manufactured. In order to manufacture a check valve, several layers of horizontal substrates are required, and the manufacturing process is complicated. In addition, the check valve of the prior art can easily cause abrasion and fatigue breakage when the drive for a long time, thereby resulting in reliability problems.

The present invention has been made in view of the problems of the prior art, and an object thereof is to provide an efficient micro pump having a relatively simple structure and minimizing the outflow of fluid.

Micro pump of the present invention for achieving the above object is a thin film; A piezoelectric element unit disposed on the thin film and deforming the thin film; A pump body forming a pumping chamber together with the thin film; An inlet channel of a predetermined length formed in the pump body and connected to one side of the pumping chamber; And an outlet channel of a predetermined length formed in the pump body and connected to the other side of the pumping chamber, wherein the inlet channel gradually increases in cross-sectional area as it approaches the pumping chamber, and the outlet channel gradually increases in cross-sectional area as it moves away from the pumping chamber. It is characterized by being increased.

The pumping chamber is further provided with a vertical partition wall for dividing the chamber space. The vertical bulkhead may be in contact with the lower surface of the thin film at the time of undeformation. In addition, a separation layer having a non-adhesion property with the thin film may be further formed at an upper surface portion of the vertical partition wall.

In addition, a hydrophobic material layer may be formed on a lower surface portion of the thin film and / or an upper surface portion of the vertical partition wall. The hydrophobic layer may be gold, platinum or polymer.

The piezoelectric element portion includes a lower electrode layer attached to the upper surface portion of the thin film, an element region layer formed on the lower electrode, and an upper electrode layer formed on the element region layer.

The upper electrode layer is composed of a first upper electrode and a second upper electrode which are separated from each other and applied voltage independently from each other, and the first upper electrode and the second upper electrode are arranged in the flow direction of the fluid.

In addition, the device region layer is composed of a first device region and a second device region separated from each other, each having a separate upper electrode and applied voltage independently of each other, the first device region and the second device region in the flow direction of the fluid Are arranged.

In addition, there is a predetermined phase delay between voltages applied to the first upper electrode and the second upper electrode and between voltages applied to the first and second device regions.

The pump body further comprises: a base forming a bottom portion of the pumping chamber; And a side wall portion forming a side portion of the pumping chamber, wherein the inlet channel and the outlet channel are formed in the form of a passage in the base portion or the side wall portion. The pump body may be formed of silicon, glass, copper or aluminum.

In addition, the vertical partition wall may be formed of silicon, glass, copper, aluminum or polymer.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following, the same reference numerals are assigned to the same elements and elements having similar functions, and the repeated description may be omitted for the convenience of understanding.

1 is a side cross-sectional view schematically showing a micropump of one embodiment according to the present invention. Figure 2 is a front sectional view schematically showing a micropump of one embodiment according to the present invention. 3A and 3B are diagrams schematically illustrating the operation of the micropump of the present invention.

1 and 2, an embodiment of the present invention is a pumping chamber 14 together with a thin film 15, a piezoelectric element portion 17 disposed on an upper surface of the thin film 15, and a thin film 15. It includes a pump body (11) to form a pump body 11, the inlet channel 12 and the outlet channel 13 is formed.

The piezoelectric element portion 17 includes a lower electrode layer 173, an element region layer 171 stacked on the lower electrode layer, and an upper electrode layer 172 stacked on the element region layer. The piezoelectric element portion 17 may be attached to the upper surface of the thin film 15 through, for example, an adhesive 174. When the voltage is applied to drive the piezoelectric element unit 17, the thin film 15 is repeatedly deformed to pump the fluid.

The pump body 11 forms the pumping chamber 14 together with the thin film 15. For example, the pump body 11 is a space in which fluid is accommodated and pumped by stacking the thin film 15 on the pump body 11. 14). In order to form the pumping chamber 14 as described above, the pump body 11 includes, for example, a base 111 forming a bottom portion of the pumping chamber 14 and a side wall forming a side portion of the pumping chamber 14. It may be made of a structure including a portion (112).

The pump body 11 is formed with an inlet channel 12 and an outlet channel 13, which are fluid communication paths. As shown in FIG. 1, the inlet channel 12 and the outlet channel 13 may be formed in the side wall portion 112 of the pump body 11, or may be formed in the base portion 111 although not shown.

The inlet channel 12 is a passage through which fluid enters the pumping chamber 14 and is connected to one side of the pumping chamber 14. Preferably, the inlet channel 12 has a predetermined length, and the closer to the pumping chamber 14, the larger the cross-sectional area becomes.

The outlet channel 13 is a passage through which fluid flows out of the pumping chamber 14 and is connected to the other side of the pumping chamber 14. Preferably, the outlet channel 13 has a predetermined length and has a structure in which the cross-sectional area gradually increases as it moves away from the pumping chamber 14.

By the configuration of the inlet channel 12 and the outlet channel 13, the pumping operation is performed as shown in Figs. 3a and 3b. That is, when a voltage is applied by the power applying unit (not shown) so that the piezoelectric element unit 17 deforms the thin film 15 upward, the volume of the pumping chamber 14 is increased so that the pressure therein becomes relatively low. do. At this time, the fluid flows in from the inlet channel 12 and the outlet channel 13 at the same time, but because of the lower flow resistance toward the inlet channel 12 due to the structure of the inlet channel 12 and the outlet channel 13, the inlet channel 12 A much larger amount of fluid enters through 12 (FIG. 3A). In contrast, when the thin film 15 is restored to its original state, a much larger amount of fluid flows out through the outlet channel 13 because the flow resistance toward the outlet channel 13 is lower (FIG. 3B). Therefore, if this operation is repeated, the pumping of the fluid flows naturally from the inlet channel 12 side to the outlet channel 13.

Preferably one embodiment of the present invention further comprises a longitudinal bulkhead 16 formed in the pumping chamber 14. The vertical partition wall 16 divides the chamber space into two, and is preferably formed to contact the lower surface portion of the thin film 15 in an undeformed state. Since the vertical partition wall 16 serves to substantially block one side of the passages of the inlet channel 12 and the outlet channel 13 when the pump is not operated, little leakage or leakage of fluid inside the pump can be minimized. To be.

Also, in order to prevent the upper surface portion of the vertical partition wall 16 and the lower surface portion of the thin film 15 from being adhered or stuck during fabrication or during pump operation, gold and titanium may be applied to the upper surface portion of the vertical partition wall 16. The separation layer 161 made of a material that does not adhere well to the thin film 15, such as aluminum, may be formed by vapor deposition. In addition, apart from the separation layer 161, a hydrophobic material layer (not shown) may be formed on an upper surface portion of the vertical partition wall 16 and / or a lower surface portion of the thin film 15. The material having hydrophobic properties may be formed of a metal such as gold or platinum, or a polymer such as PDMS or SU-8. With this configuration, since the bottom surface of the vertical bulkhead 16 and the membrane 15 is in close contact with each other when the pump is not operated, the micro-gap that may occur between them is further reduced, resulting in leakage of fluid. Can be further reduced.

The pump body 11, the thin film 15, and the vertical partition wall 16 may be formed of a material such as silicon, glass, copper, or aluminum. As an example, the pump body 11 and the vertical partition wall 16 including the base 111 and the side wall 112 may be formed by etching one substrate made of the aforementioned material. Alternatively, the photosensitive polymer may be formed on the substrate to be the base 111 by patterning through a lamination and photolithography process. In both cases, the inlet channel 12 and the outlet channel 13 can be formed in the base 111 or the side wall 112. Alternatively, a method of mixing etching and laminating may be applied, such as a method of etching a substrate to form a groove forming part of the base 111 and the sidewall 112 and stacking the remaining sidewall 112. In addition, the pumping chamber 14 may be completed by laminating and bonding the thin film 15 on the lower structure on which the pump body 11 and the vertical partition wall 16 are formed. In either case, however, it may be easy to form a groove for the pumping chamber 14, the inlet channel 12 and the outlet channel 13 and cover it with a thin film 15.

In order to connect the inlet channel 12 and the outlet channel 13 to the outside, respectively, connectors 121 and 131 may be formed at the ends of the inlet channel 12 and the outlet channel 13. The connectors 121 and 131 become areas not covered by the thin film 15, through which external elements are connected. For example, a connector 18 having a pierced hole 181 is attached on the inlet channel 12 and the outlet channel 13 to the connectors 121 and 131 so that both holes coincide, and the metal, glass Alternatively, the connector 19 made of plastic is inserted into the hole of the connector 18. The connecting tube 19 can also supply fluid to the micropump, for example by connecting microtubes (not shown). Here, by fixing the connector 18 and the connector 19 to the surrounding structure with a fixture 191, such as epoxy, it can be made a firm fixing.

Alternatively, as shown in FIG. 4, the inlet channel 12 and the outlet channel 13 are formed in a groove shape in the side wall portion 112 of the pump body 11 so as to be covered with the thin film 15. The connectors 121 and 131 of the inlet channel 12 and the outlet channel 13 may be formed as holes penetrating the base 111 of the pump body 11. In this case, the connecting tube 19 is connected to the connecting tube 19, and the connecting tube 19 may also be connected to the microtube.

5 is a side cross-sectional view schematically showing a micropump of another embodiment according to the present invention. According to another exemplary embodiment of the present invention, the upper electrode layer 172 of the piezoelectric element portion 17 is separated into a first upper electrode 172-1 and a second upper electrode 172-2, so that the element region layer 171 is formed. It can be driven independently by area.

6 is a side cross-sectional view schematically showing a micropump of another embodiment according to the present invention. In another embodiment shown in FIG. 6, the upper electrode layer 172 and the device region layer 171 are separated from each other so that the piezoelectric element is substantially the first device region 171-1 and the second device region 171-2. Are separated and driven independently of each other.

The upper electrode layer is separated into the first upper electrode 172-1 and the second upper electrode 172-2, or the upper electrode layer and the device region layer 171 are separated to substantially form the first device region 171-1. And when the piezoelectric element is separated into the second element region 171-2, the effect of substantially driving the two piezoelectric elements is obtained. In this case, the first upper electrode 172-1 and the second upper electrode 172-2, and the first device region 171-1 and the second device region 171-2 are in the flow direction of the fluid. To be arranged.

Preferably, between the voltages applied to the first upper electrode 172-1 and the second upper electrode 172-2 in the other embodiment of FIG. 5, and the first device in the other embodiment of FIG. 6. When voltages having a predetermined phase delay are respectively applied between the voltages applied between the region 171-1 and the second device region 171-2, a deformation having a shape like a traveling wave of the fluid can be produced. For example, as shown in FIG. 7, a predetermined driving voltage 30a is applied to the first upper electrode 172-1 near the inlet channel 12, and the second upper electrode 172-close to the outlet channel 13 is applied. When the driving voltage 30b having the phase delay is applied thereto, the portions of the corresponding thin films 15 are sequentially deformed, such as water waves, to pump the fluid more effectively.

Other components that are not described in the embodiments of FIGS. 5 and 6 are the same as those of the embodiments described with reference to FIGS.

The micro pump of the present invention can be pumped naturally by the shape of the inlet and outlet channels. In addition, the vertical partition wall formed in the pumping chamber can reduce the leakage of fluid when the pump is not operated. Furthermore, by forming a hydrophobic layer in the upper surface portion of the vertical partition wall and / or the lower surface portion of the thin film, leakage of fluid is further suppressed. In addition, by forming a separation layer on the upper surface portion of the vertical bulkhead, it is possible to stably manufacture and drive the pump by preventing the thin film and the vertical bulkhead from being attached or stuck during the production or operation of the pump. In addition, by separating the upper electrode layer or separating the upper electrode layer and the element region layer, the effect of driving two separate piezoelectric elements can be achieved. In this case, it is possible to pump the fluid more effectively by applying each of the driving voltages having the phase delay.

Claims (13)

For micro pumps for trace fluid flow: pellicle; A piezoelectric element unit disposed on an upper surface of the thin film to deform and operate the thin film; A pump body forming a pumping chamber together with the thin film; An inlet channel of a predetermined length formed in the pump body and connected to one side of a pumping chamber; And An outlet channel of a predetermined length formed in the pump body and connected to the other side of the pumping chamber, The inlet channel gradually increases in cross-sectional area as it approaches the pumping chamber, and the outlet channel gradually increases in cross-sectional area as it moves away from the pumping chamber, The pumping chamber is a micro-pump, characterized in that the vertical partition wall for partitioning the chamber space is provided. delete The method according to claim 1, The vertical bulkhead is in contact with the lower surface of the thin film at the time of non-deformation. The method according to claim 3, The upper part of the vertical partition wall micropump is further formed with a separation layer having a non-adhesive with the thin film. The method according to claim 3, And a hydrophobic material layer formed on a lower surface portion of the thin film or an upper surface portion of the vertical partition wall. The method according to claim 5, Wherein said layer of hydrophobic material is gold, platinum or a polymer. The method according to claim 1, wherein the piezoelectric element portion: A lower electrode layer attached to an upper surface portion of the thin film, An element region layer formed on the lower electrode; And a top electrode layer formed on the device region layer. The method according to claim 7, The upper electrode layer is composed of a first upper electrode and a second upper electrode which are separated from each other and applied voltage independently of each other, And the first and second upper electrodes are arranged in the flow direction of the fluid. The method according to claim 8, The device region layer is composed of a first device region and a second device region separated from each other, the first device region and the second device region is arranged in the flow direction of the fluid, And the first and second upper electrodes are disposed on the first and second device regions, respectively. The method according to claim 8 or 9, And a predetermined phase delay between the voltages applied to the first upper electrode and the second upper electrode. The pump body of claim 1 wherein the pump body is: A base forming a bottom portion of the pumping chamber; A side wall portion forming a side portion of the pumping chamber, The inlet channel and outlet channel is formed in the form of a passage in the base portion or the side wall portion. The method according to claim 1, The pump body is formed of silicon, glass, copper or aluminum. The method according to claim 1, The vertical bulkhead is formed of silicon, glass, copper, aluminum or polymer.

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