JP2007009726A - Micropump and micropump system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micropump having a construction simplified and reduced in size as compared with a conventional micropump and to provide a micropump system. <P>SOLUTION: In the micropump 1 of the invention, a flow path substrate 2 is provided with a pressure chamber 3 having one end and another end and storing liquid inside, the one end of the pressure chamber 3 is connected with a flow path 4 having flow path resistances different according to a direction in which the liquid flows, the other end of the pressure chamber is opened, and an actuator 6 is provided for generating a pressure wave to the liquid in the pressure chamber 3, which is propagated between the one end and the other end. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a micropump and a micropump system for conveying a minute amount of fluid with high accuracy.

  2. Description of the Related Art Conventionally, a micro-pump for transporting a minute amount of liquid includes a valveless pump using a nozzle whose flow path resistance is different depending on the liquid flow direction.

  The structure and principle of this valveless pump are described in Non-Patent Document 1 (Micro ElectroMechanical Systems (1996) pages 378 to 383) and Non-Patent Document 2 (Micro ElectroMechanical Systems (1996) pages 479 to 484). Yes.

  In both of the above-mentioned non-patent documents, a pressure chamber is formed on one plane of a silicon substrate, and nozzles connected to both ends of the pressure chamber so as to sandwich the pressure chamber and having different flow path resistances depending on the liquid flow direction are opposed to the nozzle Then, the glass substrate is bonded, and a piezoelectric element is disposed on the silicon substrate on which the pressure chamber is located or on the opposite surface on the glass substrate.

  Here, the nozzles with different flow path resistances depending on the direction in which the liquid flows are such that the opening area of the nozzle on the side where the liquid flows into the pressure chamber gradually increases in the direction of the pressure chamber and the nozzle on the side where the liquid flows out The opening area is sequentially reduced in the direction, and the flow path resistance is smaller in the direction in which the opening area is sequentially enlarged and the direction in which the opening area is sequentially reduced. Then, by driving the piezoelectric element, the silicon substrate or the glass substrate is deformed, and the volume of the pressure chamber is expanded / contracted, so that the fluid flow is directed in the direction in which the flow path resistance of the nozzle is small.

  Further, examples of applying this principle are those described in Patent Document 1 (Japanese Patent Laid-Open No. 10-110682) and Patent Document 2 (Japanese Patent Laid-Open No. 2001-322099).

  The technique described in Patent Document 1 is characterized by a channel shape that can maintain a large channel resistance difference without being influenced by the processing accuracy of the channel. Thereby, it is said that a micropump excellent in mass productivity can be provided.

Further, in the technique described in Patent Document 2, the first flow path whose flow resistance changes greatly according to the differential pressure, and the flow resistance is less affected by the differential pressure than the first flow path. Two flow paths are provided at both ends of the pressure chamber, and the ratio of the flow path resistances of the first flow path and the second flow path caused by expansion / contraction of the pressure chamber is made different. Thus, it is possible to provide a micro pump capable of transporting liquid in both forward and reverse directions.
Japanese Patent Laid-Open No. 10-110681 JP 2001-322099 A Micro ElectroMechanical Systems (1996) pages 378-383. Micro ElectroMechanical Systems (1996) pages 479-484.

  However, in the conventional technique, in order to obtain a certain amount of flow rate and fluid pressure, it is necessary to increase the volume change amount of the pressure chamber to some extent, and accordingly, the pressure chamber itself needs to be enlarged. In principle, it was necessary to provide nozzles at both ends of the pressure chamber.

  Therefore, there is a limit in mechanical processing such as grinding, and nozzles and diaphragms with different flow path resistances are processed and formed on the silicon substrate by the photolithography process and the etching process depending on the flow direction of the pressure chamber and the liquid. For this reason, expensive manufacturing apparatuses such as an exposure apparatus and a dry etching apparatus are required.

  In addition, the manufacturing process such as bonding of the actuator and the diaphragm is complicated. Furthermore, in order to increase the flow rate and the pressure, it is necessary to increase the volume change amount of the pressure chamber to some extent, and it has been difficult to reduce the size and increase the integration.

  Accordingly, an object of the present invention is to provide a micropump and a micropump system that have a simplified structure and a reduced size as compared with the conventional one.

  In order to achieve the above object, the present invention has taken the following measures. That is, the micropump of the present invention is characterized in that the flow path substrate is provided with a pressure chamber having one end portion and the other end portion for storing liquid therein, and one end portion of the pressure chamber has a liquid chamber. A flow path having different flow path resistances is connected depending on the flow direction, the other end of the pressure chamber is an open portion, and propagates between the one end and the other end with respect to the liquid in the pressure chamber. An actuator for generating a pressure wave is provided.

  According to the configuration of the present invention, the liquid is conveyed by the vibration of the pressure wave (reciprocating motion between the one end and the other end). Therefore, the structure of the micropump can be simplified as compared with the case where the liquid is conveyed by the change in the volume of the conventional pressure chamber.

  Specifically, in order to obtain a predetermined (somewhat large) flow rate and fluid pressure, it is necessary to generate a large pressure wave. For this purpose, the high speed of displacement of the pressure chamber is an important factor. In other words, since a displacement amount of the pressure chamber is not required, a large pressure chamber is not required.

  In principle, the flow path having different flow path resistance depending on the flow direction of the liquid is only one end of the pressure chamber, and the other end may have an open shape. Mechanical machining can also be applied.

  In the present invention, the flow path substrate is preferably made of a piezoelectric body, and the piezoelectric body constitutes the actuator.

  According to this configuration, the pressure chamber can be formed relatively easily and inexpensively by grinding using a dicing blade, the diaphragm is unnecessary, and the structure of the micropump can be simplified. Furthermore, since the resistance force of the diaphragm is not generated, the displacement speed of the piezoelectric element (part of the pressure chamber) and the electromechanical conversion efficiency are improved, and high-speed and high-efficiency operation is possible.

In the present invention, the channel is preferably formed on the channel substrate.
According to this configuration, the flow path can be formed by grinding as in the formation of the pressure chamber. Moreover, since a separate member is not used, manufacturing cost can be reduced.

In the present invention, it is preferable that a plurality of the pressure chambers are arranged.
According to this configuration, there is a limit to the flow rate and fluid pressure that can be obtained in a single pressure chamber (single channel), but by providing a plurality of pressure chambers (multi-channeling), the desired flow rate and fluid pressure can be reduced. Obtainable.

  In the present invention, it is preferable that a driving device for selectively driving the actuator with respect to the plurality of pressure chambers is provided.

According to this configuration, the flow rate and fluid pressure obtained can be adjusted over a wide range.
In this invention, it can be set as the structure from which the direction of the said flow path differs in these pressure chambers.

  According to this configuration, the liquid can be transported in both forward and reverse directions by the channel to be driven.

  In the present invention, a pressure chamber having a flow path having the same flow path resistance at one end regardless of the flow direction of the liquid is disposed between the pressure chambers having different flow path directions. Can do.

  According to this configuration, the channel in which the flow path having the same flow path resistance is arranged regardless of the flow direction of the liquid does not contribute to the transport (suction or discharge) of the liquid, but the suction channels located on both sides thereof And the discharge channel can be prevented from interfering with each other, and stable operation can be obtained.

  A feature of the micropump system of the present invention is that a plurality of containers for storing different liquids, a plurality of the micropumps connected to the plurality of containers, and the plurality of micropumps conveyed through the plurality of micropumps. In that it comprises a container for mixing the liquid.

  According to the micropump of the present invention, the structure is simpler than that of a conventional micropump, and it is manufactured by mechanical cutting with a dicing blade without using an expensive device such as a photolithographic device or a dry etching device. Can do. For this reason, a low-cost micropump can be supplied. In addition, it is possible to provide a high-performance micro pump capable of adjusting the flow rate and pressure of the transport liquid over a wide range and with high accuracy. Furthermore, the liquid can be easily transferred in both directions.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3, a micropump 1 according to an embodiment of the present invention is provided with a pressure chamber 3 having a first end and a second end on a flow path substrate 2 and storing liquid therein. . A flow path 4 having different flow path resistances is connected to one end of the pressure chamber 3 depending on the direction in which the liquid flows. The other end of the pressure chamber 3 is an open portion 5. An actuator 6 that generates a pressure wave propagating between the one end and the other end of the liquid in the pressure chamber is provided.

  The flow path resistance of the open portion 5 is smaller than that of the flow path 4, and is preferably opened corresponding to the cross section of the pressure chamber.

  The flow path substrate 2 is made of a piezoelectric body, and the piezoelectric body constitutes the actuator 6. A flow path 4 having a flow path resistance that varies depending on the direction in which the liquid flows is also formed on the flow path substrate 2. Further, a plurality of the pressure chambers 3 are arranged. That is, a plurality of pressure chambers 3 are provided in parallel to each other on the same flow path substrate 2. Similarly, the flow path 4 and the open portion 5 are also provided in each pressure chamber 3. A driving device 7 that selectively drives the actuator 6 with respect to the plurality of pressure chambers 3 is provided.

  A cover plate 8 is bonded to the flow path substrate 2. An FPC (flexible substrate) 9 is electrically connected to the flow path substrate 2. The driving device 7 is provided in the FPC 9. The driving device 7 is composed of a driver IC.

  In this embodiment, the flow path substrate 2 (hereinafter also referred to as a piezoelectric substrate) polarizes the first piezoelectric substrate 10 and the second piezoelectric substrate 11 in a shear mode polarized in the thickness direction. They are attached so that the directions (arrows in the figure) are opposed to each other.

  A groove having a certain depth from the first piezoelectric substrate 10 side to the second piezoelectric substrate 11 is provided in the flow path substrate 2, and the pressure chamber 3 is formed.

  The pressure chamber 3 can be formed relatively easily and inexpensively only by grinding with a dicing blade, whereas a conventional micropump has formed a silicon substrate by a photolithography process and an etching process.

  Next, the drive electrodes 13 are provided on at least both side surfaces of the partition wall 12 made of a piezoelectric material between the plurality of pressure chambers 3 formed by machining a plurality of grooves by a dicing blade, and the external connection electrodes 14 are provided on the upper surface of the flow path substrate 2. Form.

A method of forming the drive electrode 13 and the external electrode 14 is as described below.
Simultaneously with the processing of the groove by the dicing blade, which is the previous step, a shallow groove (concave portion) of about several μm is formed at a location corresponding to the external connection electrode 14, and the flow path substrate 2 is obliquely above the flow path substrate 2. A metal film is formed by sputtering on the upper surface and the side wall of the partition wall 12. Then, by grinding the entire upper surface of the flow path substrate 2, only the excess metal film is removed and only the metal film in the recess is inevitably left. Can do.

  In this state, since the drive electrode 13 is exposed in the pressure chamber 3, an insulation process such as formation of an insulating film is performed as necessary. As the insulating film, parylene resin (Parylene Japan) has excellent mechanical strength and chemical resistance.

  Next, “flow path 4 having different flow path resistance depending on the direction of flow of the liquid” (hereinafter sometimes referred to as “nozzle 4”) is formed. The nozzle 4 is formed by grinding a second groove that communicates with one end of the pressure chamber 3 and has a cross-sectional area smaller than that of the pressure chamber 3 and the cross-sectional area sequentially changes.

  Here, using a dicing blade whose cutting width is narrower than that in the groove processing of the pressure chamber 3, the grinding depth is sequentially reduced from the pressure chamber 3 side. For this reason, the flow path resistance of the nozzle 4 is smaller in the direction of flowing into the pressure chamber 3 from the outside of the micropump 1.

  And the said cover plate 8 is bonded together on the upper surface of the flow path board | substrate 2, and the upper surface of the pressure chamber 3 and the flow path 4 which are formed in the flow path board | substrate 2 is obstruct | occluded.

  An opening 15 is formed in the cover plate 8. The opening 15 penetrates in the thickness direction of the cover plate. The opening 15 is located at the other end of the pressure chamber 3. The other end of the pressure chamber 3 located in the opening 15 constitutes the opening 5.

  The opening 15 of the cover plate 8 is formed continuously over the open portions 5 of the plurality of pressure chambers 3. Therefore, the opening 15 serves as a liquid chamber 102b common to the pressure chambers 3.

Further, the driving device 7 is connected to the exposed external connection electrode 14. (In FIG. 1, the FPC 9 and the driver IC are illustrated as a part of the driving device 7 (driving circuit). In FIGS. 2 and 3, those corresponding to the driving circuit are not illustrated.)
FIG. 4 schematically shows the connection state of the driver IC of the driving device 7 of the micropump 1.

  The drive device 7 is configured to be able to supply different voltage waveforms to the drive electrodes 13 for each pressure chamber 3 (each channel). Note that the arrows in the figure indicate the polarization directions of the piezoelectric substrates 10 and 11.

A method for driving the micropump 1 will be described with reference to FIG.
In order to simplify the description, the operation for the three channels Ch2 to 4 when the drive voltage is added to the five channels Ch1 to 5 will be described.

  In this type of micropump, the partition wall 12 is shear-deformed by applying a drive voltage to the drive electrode 13 of each channel and generating an electric field in the partition wall 12 between the channels. As a result, the pressure chamber 3 expands or contracts, and pressure can be applied to the liquid inside.

  Specifically, when there is no potential difference between the channels as shown in the state 1 of FIG. 5B (all in the state 1 is at the low level), as shown in the state 1 of FIG. No deformation occurs.

  Next, as shown in state 2 in FIG. 5B, by setting only Ch1, Ch3, and Ch5 to the high level, a potential difference is generated between adjacent Ch2 and Ch4, and the pressure chamber 3 of Ch1, Ch3, and Ch5. The partition wall 12 is deformed in the direction in which it expands.

  Conversely, as shown in state 3 of FIG. 5B, when the drive voltage is applied so that Ch1, Ch3 and Ch5 have a negative potential relative to Ch2 and Ch4, state 3 of FIG. Thus, the partition wall 12 is deformed in the direction in which the pressure chambers 3 of Ch1, Ch3, and Ch5 contract.

  Further, as shown in state 4, by setting Ch2, Ch3 and Ch4 to the same potential (in this case, high level), the pressure chamber 3 of Ch3 can be brought into a non-operating state as in state 1.

  As described above, the channel can be selectively driven by adjusting the drive waveform applied to each channel. That is, by adjusting the number of channels to be driven among a plurality of channels, the flow rate and fluid pressure of the liquid to be conveyed can be set in a wide range.

  Further, since the partition wall 12 is shared with adjacent channels, the movement of expansion / contraction is reversed between adjacent channels. This has the effect of reducing pulsations that occur during liquid conveyance.

  Next, differences from the conventional micro pump will be described. The conventional micropump has a structure having nozzles both upstream and downstream of the pressure chamber. Further, the volume change of the pressure chamber directly acts, and the liquid is sucked or discharged following the expansion or contraction of the pressure chamber.

  In the micropump 1 of the present invention, the nozzle 4 is provided only on one side of the pressure chamber 3, and the other is opened corresponding to the cross-sectional area of the pressure chamber 3. Moreover, the point from which the pressure wave which propagates in the liquid in the pressure chamber 3 intervenes between the volume change of the pressure chamber 3 and the flow of a liquid differs from a prior art.

  The state of the pressure wave propagating in the pressure chamber 3 will be described with reference to FIG. FIG. 6 is a diagram for explaining the vibration period of the pressure wave in the pressure chamber 3. In addition, although the opening part by the nozzle 4 exists in the one end part of the pressure chamber 3, since the area is small enough compared with the cross-sectional area of the pressure chamber 3, and it does not affect the great number of pressure wave propagation, it is the obstruct | occluded state Therefore, in FIG. 6, it is shown in a closed state.

  First, as shown in FIG. 6A, when the pressure chamber 3 rapidly expands, a negative pressure is generated in the entire pressure chamber 3 (in the drawing, the negative pressure state is represented by a circle “−”). is doing). In addition, the time which passed on the basis of the time of negative pressure generation is set to time t.

  Due to the generation of the negative pressure, as shown in FIG. 6B, the liquid in the opening 15 which is a common liquid chamber flows into the pressure chamber 3 as indicated by an arrow. The interface between where the liquid flows and where there is no flow is a pressure wave and propagates in the pressure chamber 3 toward the nozzle 4.

  FIG. 6C shows a state in which the pressure wave first reaches the wall surface on the nozzle 4 side. If the length of the pressure chamber 3 is L and the sound velocity of the pressure wave in the liquid is a, it takes time t = L / a to reach this state.

  Thereafter, the inflow of liquid continues, and the pressure wave is reflected by the wall surface on the nozzle 4 side and propagates in the direction of the opening 5 while changing its direction. As a result, as shown in FIG. 6D, the pressure chamber 3 gradually becomes a positive pressure from the nozzle 4 side (in the figure, the positive pressure state is represented by a “+” circle). )

  As shown in FIG. 6E, when the time t = 2L / a has elapsed, the flow of the liquid stops, and the entire pressure chamber 3 becomes positive pressure. With this positive pressure, as shown in FIG. 6F, the liquid begins to flow out from the pressure chamber 3 to the open portion 5 side, and the pressure wave propagates again toward the nozzle 4 side. As shown in FIG. 6G, when the time t = 3 L / a has elapsed, the pressure wave reaches the wall surface on the nozzle 4 side.

  Furthermore, since the outflow of the liquid is continued, the pressure wave is reflected on the wall surface on the nozzle 4 side and propagates toward the opening 5, and as shown in FIG. The negative pressure gradually increases from the nozzle 4 side.

  Then, as shown in FIG. 6 (i), when the time t = 4L / a has elapsed, the pressure wave reaches the open portion 5 side, and the entire pressure chamber 3 becomes negative pressure. The state is the same as the state at time t = 0 shown in a).

  Thus, although there is some attenuation, the pressure wave repeats vibration at the vibration period T0 = 4 L / a.

  In considering the majority of pressure wave propagation, the opening due to the nozzle 4 is ignored. However, considering the flow of the liquid accompanying the propagation of the pressure wave, the opening due to the nozzle 4 is important. When the flow path resistance of the nozzle 4 is not directional, the opening and closing of the liquid through the opening of the opening 5 and the opening of the nozzle 4 are canceled out within one vibration cycle of the pressure wave. However, when the nozzle 4 has different flow path resistances in the liquid flow direction, naturally, a larger amount of liquid flows in the direction in which the flow path resistance is smaller. On the other hand, the flow path resistance of the opening on the open part 5 side is sufficiently smaller than the flow path resistance of the nozzle 4 in nature, so that the difference in flow rate generated at the nozzle 4 is absorbed and the flow direction of the liquid is almost affected. Don't give.

This will be described with reference to FIG.
7A, 7B, 7C, and 7D correspond to the states of FIGS. 6B, 6D, 6F, and 6H, respectively. That is, the inflow / outflow of the liquid through the nozzle 4 is determined by the pressure state in the vicinity of the nozzle 4 in the pressure chamber 3, and the outflow is in the case of positive pressure and the inflow in the case of negative pressure.

  Due to the difference in flow path resistance of the nozzle 4, the flow rate increases when it flows in, and decreases relatively when it flows out, so that the flow rate difference becomes the flow rate difference to the opening 15 that is a common liquid chamber. . As a result, the overall flow of the liquid is directed in a direction in which the flow path resistance of the nozzle 4 is small.

  That is, in the direction (arrangement) of the nozzle 4 shown in FIG. 3, the nozzle 4 side is an inflow portion, and the open portion 5 side is an outflow portion.

  As described above, the micropump 1 of the present invention generates a pressure wave reciprocating (vibrating) in the pressure chamber 3 and a liquid flow associated therewith even if the pressure chamber 3 is merely expanded once. The liquid can be repeatedly conveyed in a predetermined direction by the nozzle 4 having different flow path resistance depending on the liquid flowing direction.

  In the present embodiment, the pressure chamber 3 is contracted again in a state where the vibration of the pressure wave is in the pressure chamber 3, and the contraction is performed at a timing synchronized with the vibration of the existing pressure wave. That is, a new pressure wave generated by contraction of the pressure chamber 3 and an existing pressure wave can be resonated to generate a larger pressure. That is, by using a drive waveform in which the pulse width of the drive waveform is approximately equal to 1/2 of the oscillation period of the pressure wave: T0 in the pressure chamber 3 into which the liquid has flowed, a new pressure wave and an existing pressure wave To resonate. As a result, the amount of liquid flowing into the pressure chamber 3 can be increased, so that the liquid transport efficiency can be increased. It has been proved in the experimental results shown in FIG. 8 that such an effect can be obtained by using a drive waveform whose pulse width is substantially equal to 1/2 of the vibration period: T0.

  FIG. 8 is a graph showing experimental results. In this experiment, with the drive frequency kept constant (37 kHz), the pressure chamber 3 expansion and contraction holding time (pulse width of the drive signal) was changed, and the amount of discharged liquid was measured. The length L of the pressure chamber 3 used in this experiment is 1.15 mm, and the speed of sound a in the liquid of the pressure wave is approximately 1000 m / sec.

  The experimental results show that the amount of discharged liquid is maximized when the pressure chamber 3 expansion and contraction holding time is 2.25 μsec. In this experiment, since the vibration period T0 of the existing pressure wave is 4L / a = 4 × 1.15 (mm) / 1000 (m) = 4.6 μsec, 1/2 of the vibration period: T0 is 2 .3 μsec. Therefore, in this experiment, the pulse width (2.25 μsec) of the pulse waveform that maximizes the amount of discharged liquid is substantially equal to ½ of the oscillation period: T0 (2.3 μsec). It has proved preferable to use drive waveforms.

  What is shown in FIG. 9 is a micropump system for using a plurality of micropumps 1 of the present invention to mix different liquids with a minute amount and with high accuracy. That is, the suction sides of the plurality of micropumps 1 are connected to containers 16 in which different liquids are stored, and the discharge side is connected to the same container 17 in which the liquid mixture is stored, and the drive of each micropump 1 is controlled. By mixing the minute amount of liquid with high accuracy. Thereby, the micropump used with a chemical analyzer etc. can be reduced in size.

  FIG. 10 shows another embodiment of the present invention. The difference from the embodiment shown in FIGS. 3 and 7 is that the direction (arrangement) of the nozzle 4 is opposite. .

  In this embodiment, the nozzle 4 is configured such that the flow path resistance decreases in the direction in which the liquid flows out from the pressure chamber 3 to the outside of the micropump 1. In this case, as indicated by the arrows in the figure, the liquid is conveyed from the open portion 5 side to the outside of the micropump 1 through the pressure chamber 3 and the nozzle 4. The operation principle is the same as that of the embodiment shown in FIG. 3 and FIG.

  FIG. 11 shows another embodiment of the present invention, in which the flow paths (nozzles) 4 are different in the plurality of pressure chambers 3.

  In this embodiment, the arrangement of the nozzles 4 shown in FIG. 7 and the arrangement of the nozzles 4 shown in FIG. 10 are formed on the same flow path substrate 2. Thereby, the liquid can be transported in both directions by selecting and driving the channel (pressure chamber 3). In addition, the arrow in a figure represents the direction in which the liquid is conveyed.

  In this case, by providing the pressure chamber 3 (dummy channel) in which the nozzles 18 having the same flow path resistance are disposed between the suction channel and the discharge channel regardless of the direction in which the liquid flows, the suction channel and the discharge channel are provided. It is possible to prevent mutual interference between channels for use and obtain a stable operation.

  Here, the nozzle 18 having the same flow path resistance regardless of the flowing direction of the liquid is a nozzle having a uniform cross-sectional area. The dummy channel provided with the nozzle 18 having the same flow path resistance regardless of the flow direction of the liquid cancels out the amount of liquid flowing in and out through the nozzle 18 when the pressure chamber 3 is driven. Although not contributing to the conveyance, mutual interference (crosstalk) can be prevented by providing a dummy channel between the suction channel and the discharge channel.

  In each embodiment of the present invention, a piezoelectric body is used as the actuator 6 and a shear mode piezoelectric body is used. However, the present invention is not limited to this. For example, other than a bending mode type, a longitudinal mode type, etc. Any structure that can generate pressure in the pressure chamber, such as a piezoelectric body or an electrostatic actuator, may be used.

  Further, in the present embodiment, the pressure chamber 3 is formed in the piezoelectric substrate 2 and is configured to directly apply pressure to the liquid by deformation of the partition wall 12 made of a piezoelectric body, but is not limited thereto. Instead, the actuator 6 may have a diaphragm as in the prior art, and may be configured to transmit the deformation of the actuator to the diaphragm and apply pressure to the liquid via the diaphragm.

  In the present embodiment, the flow path 4 having different flow path resistances depending on the liquid flow direction is formed on the piezoelectric substrate 2. However, the present invention is not limited to this, and another member is used. The structure which joined what was formed may be sufficient. For example, by drilling holes in a polyimide sheet with an excimer laser, the taper-shaped cross-sectional shape is obtained. Therefore, the present invention is applicable to the micropump of the present invention. The advantage in this case is that the processing accuracy is relatively good compared to machining by cutting in forming a channel having different channel resistances depending on the direction in which the liquid flows.

  In the present embodiment, the pressure chamber 3 expands and contracts. However, both expansion and contraction are not essential, and expansion and neutrality (state before expansion), or contraction and neutrality (before contraction). The present invention can be realized even with only the state. However, as the pressure fluctuation in the pressure chamber 3 is larger, the amount of the cleaning liquid inflow can be increased. Therefore, it is more preferable that the pressure chamber 3 repeats expansion and contraction as in the present embodiment. .

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be used for, for example, a micro fluid supply device used for medical treatment, chemical analysis, and the like.

1 is an exploded perspective view schematically showing a micropump according to an embodiment of the present invention. It is a top view of the micropump concerning FIG. FIG. 3 is a cross-sectional view taken along line A-A ′ of FIG. 2. It is the schematic which shows the electrical connection of the micropump concerning one embodiment of this invention. It is the schematic which shows the operation state of the micropump concerning one embodiment of this invention. It is a figure explaining the pressure wave which propagates in a pressure chamber. It is a figure explaining the flow of the liquid through a pressure chamber. It is a graph which shows the relationship between a drive pulse width and a liquid feeding amount. It is a block diagram of the micropump system of this invention. It is a plane schematic diagram of the micropump concerning other embodiments of the present invention. It is a plane schematic diagram of the micropump concerning other embodiments of the present invention.

Explanation of symbols

  1 micro pump, 2 flow path substrate (piezoelectric substrate), 3 pressure chamber, 4 flow path (nozzle) having different flow path resistance depending on the flow direction of liquid, 5 open part, 6 actuator, 7 driving device, 16 different liquids A plurality of containers for storing liquid, 17 a container for mixing liquid, and 18 a flow path having the same flow path resistance regardless of the direction in which the liquid flows.

In order to achieve the above object, the present invention has taken the following measures. That is, the micro-pump of the present invention, the flow path substrate, and a one end and the other end, said other end is an open portion, the first and second pressure chamber for storing the liquid therein provided, the first and first and second flow path having a flow path resistance that is different depending on the direction of flow of the liquid is connected to one end of the second pressure chamber, to the first and the second pressure chamber of the liquid And an actuator for generating a pressure wave propagating between the one end and the other end.

In the present invention, the pressure chamber shall be the more deployed configuration.
According to this configuration, there is a limit to the flow rate and fluid pressure that can be obtained in a single pressure chamber (single channel), but by providing a plurality of pressure chambers (multi-channeling), the desired flow rate and fluid pressure can be reduced. Obtainable.

In the present invention, a third channel having the same channel resistance is provided at one end portion between the first and second pressure chambers in which the directions of the first and second channels are different from each other regardless of the direction in which the liquid flows. A third pressure chamber is disposed .

Due to the generation of the negative pressure, as shown in FIG. 6B, the liquid in the opening 15 which is a common liquid chamber flows into the pressure chamber 3 as indicated by an arrow. The interface between where the liquid flows and where there is no flow is the position of the pressure wave , and propagates in the pressure chamber 3 toward the nozzle 4.

Claims (8)

The flow path substrate is provided with a pressure chamber that has one end and the other end and stores liquid therein.
A flow path having a different flow path resistance is connected to one end of the pressure chamber depending on the direction in which the liquid flows, and the other end of the pressure chamber is an open portion.
A micropump comprising an actuator that generates a pressure wave propagating between the one end and the other end of the liquid in the pressure chamber.   2. The micropump according to claim 1, wherein the flow path substrate is made of a piezoelectric material, and the piezoelectric material constitutes the actuator.   The micropump according to claim 2, wherein the flow path is formed in the flow path substrate.   The micro pump according to claim 1, wherein a plurality of the pressure chambers are arranged.   The micropump according to claim 4, further comprising a driving device that selectively drives the actuator with respect to the plurality of pressure chambers.   The micropump according to claim 5, wherein directions of the flow paths are different in the plurality of pressure chambers.   7. A pressure chamber in which a flow path having the same flow path resistance at one end is arranged between the pressure chambers having different flow path directions regardless of the flow direction of the liquid. Micro pump. A micropump system comprising a plurality of containers for storing different liquids, a plurality of micropumps connected to each of the plurality of containers, and a container for mixing the liquids conveyed via the plurality of micropumps In
The micro pump system according to claim 1, wherein the micro pump is the micro pump system according to claim 1.

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