Title:
PDMS valve-less micro pump structure and method for producing the same
Kind Code:
A1


Abstract:
A PDMS valve-less micro pump structure includes a PDMS body having a contour surface, a membrane covering the contour surface of the PDMS body, and a PZT actuator located on the membrane. The contour surface of the PDMS body to be sealed by the membrane and the PZT actuator has in series a lead-in cavity, a lead-in nozzle structure, a main cavity, a lead-out nozzle structure, and a lead-out cavity. The PZT actuator is located right above the main cavity. By providing the PDMS as a material to form the body of the micro pump, the micro pump can then be mass-produced with less cost and simpler structuring. Also, substantial elasticity and bio-compatibility for the micro pump can be achieved.



Inventors:
Liu, Min-sheng (Hsinchu-Hsien, TW)
Wang, Chi-chuan (Hsinchu Hsien, TW)
Yang, Bing-chwen (Hsinchu, TW)
Cheng, Yu-ching (Chang Hua Hsien, TW)
Chang, Wen-jeng (Taichung City, TW)
Application Number:
11/041956
Publication Date:
04/20/2006
Filing Date:
01/26/2005
Assignee:
Industrial Technology Research Institute
Primary Class:
Other Classes:
417/413.1
International Classes:
F04B17/00
View Patent Images:
Related US Applications:
20060013709Battery-powered spray wandJanuary, 2006Hudson et al.
20080219860PROTECTION SYSTEM FOR AIR COMPRESSOR ASSEMBLYSeptember, 2008Caito et al.
20040170514Electrically-driven pump for motor vehicle windscreen washersSeptember, 2004Mota Lopez et al.
20080159891Pumping Device for Nuclear FacilityJuly, 2008Schulze et al.
20080193308Water Pressurized Manual Lavatory De-Blocking Manual PumpAugust, 2008Korcoban
20020168268Pneumatic microfluid driving system and methodNovember, 2002Lin et al.
20070128050System and method for a pump with reduced form factorJune, 2007Cedrone et al.
20060165539Device for transmitting the rotating movement to a driven shaft, in particular for fluid recirculating pumpsJuly, 2006Boffelli et al.
20090060765AXIAL PISTON PUMP, AND POWER TRANSMISSION DEVICE WITH AXIAL PISTON PUMPMarch, 2009Kuwabara et al.
20090004027Ventilation of an Operating ElementJanuary, 2009Ingenbleek et al.
20090304525Linear Drive and Linear Compressor with Adaptive OutputDecember, 2009Reinschke



Primary Examiner:
COMLEY, ALEXANDER BRYANT
Attorney, Agent or Firm:
BRUCE H. TROXELL (FALLS CHURCH, VA, US)
Claims:
I claim:

1. A PDMS valve-less micro pump structure, comprising: a PDMS body, having a contour surface, the contour surface further being curved to form thereof: a main cavity; a lead-in cavity, located aside to the main cavity and in spatial communication with the main cavity through a lead-in nozzle; and a lead-out cavity, located also aside to the main cavity and in spatial communication with the main cavity through a lead-out nozzle; a membrane having a center hole, layered on top of the PDMS body by sealing the lead-in cavity, the lead-in nozzle, the lead-out nozzle and the lead-out cavity but having the center hole positioned on top of the main cavity; and a PZT actuator, mounted on top of the membrane by a predetermined peripheral sealing way so as to seal the main cavity.

2. The PDMS valve-less micro pump structure according to claim 1, wherein said membrane is made of a PDMS material.

3. The PDMS valve-less micro pump structure according to claim 1, wherein said membrane has a thickness ranged between 200 μm and 300 μm.

4. The PDMS valve-less micro pump structure according to claim 1, wherein said predetermined peripheral sealing way is a sealing way having supports at nodes of said PZT actuator.

5. The PDMS valve-less micro pump structure according to claim 1, wherein said predetermined peripheral sealing way is a sealing way having supports at a periphery of said PZT actuator.

6. The PDMS valve-less micro pump structure according to claim 1, wherein said predetermined peripheral sealing way is a sealing way having bonding at a periphery of said PZT actuator.

7. The PDMS valve-less micro pump structure according to claim 1, wherein said PZT actuator has a bottom coated with a PDMS material.

8. The PDMS valve-less micro pump structure according to claim 1, wherein said PZT actuator further comprising: a PZT plate; a copper plate, layered under the PZT plate; an insulation layer, sandwiched between the PZT plate and the copper plate to avoid electrically shorting in between; and a bottom layer, layered under the copper plate to prohibit direct contact between the copper plate and a fluid in said main cavity.

9. The PDMS valve-less micro pump structure according to claim 8, wherein said insulation layer is made of a PDMS material.

10. The PDMS valve-less micro pump structure according to claim 8, wherein said bottom layer is made of a PDMS material.

11. A method for producing a PDMS valve-less micro pump structure, comprising the steps of: preparing a die, the die having a profiling protrusion forming on a top surface thereof; pouring a PDMS material in a fluid state onto the top surface of the die to cover fully the profiling protrusion; performing a predetermined baking process on the die and the PDMS material to solidify the PDMS material; and removing the solidified PDMS material from the die to complete a production of the PDMS valve-less micro pump structure; wherein the profiling protrusion of the die is characterized to form concavely a main cavity, a lead-in cavity, a lead-in nozzle, a lead-out cavity and a lead-out nozzle in the PDMS material.

12. The method for producing a PDMS valve-less micro pump according to claim 11, wherein said die is made of a PMMA material.

13. The method for producing a PDMS valve-less micro pump according to claim 11, wherein said PDMA material in the fluid state is prepared by mixing a Sylgard 184 base and a Sylgard 184 agent at a 10:1 ratio.

14. The method for producing a PDMS valve-less micro pump according to claim 13, wherein said Sylgard 184 base and said Sylgard 184 agent are blended by a magnetic stirrer by stirring a predetermined period at a predetermined speed and then slowing to de-bubble said PDMS material.

15. The method for producing a PDMS valve-less micro pump according to claim 11, wherein said predetermined baking process is a vacuum-baking process including a 20-30 minute low-pressure de-bubbling step, a heating step at 110-130° C. for 2-4 hours, and a free cooling step.

16. A method for producing a PDMS valve-less micro pump, comprising the steps of: preparing a PDMS body, the PDMS body having a main cavity, a lead-in cavity, a lead-in nozzle, a lead-out cavity and a lead-out nozzle formed concavely on a contour surface thereof; adhering a membrane having a center hole onto the contour surface of the PDMS body by sealing the lead-in cavity, the lead-in nozzle, the lead-out nozzle and the lead-out cavity but having the center hole positioned on top of the main cavity; mounting a PZT actuator onto the membrane by a predetermined peripheral sealing way so as to seal the main cavity; and performing a baking process to solidify the combination of the PDMS body, the membrane, and the PZT actuator.

17. The method for producing a PDMS valve-less micro pump according to claim 16, wherein said membrane is made of a PDMS material.

18. The method for producing a PDMS valve-less micro pump according to claim 16, wherein said membrane has a thickness ranged between 200 μm and 300 μm.

19. The method for producing a PDMS valve-less micro pump according to claim 16, wherein said predetermined baking process is a vacuum-baking process including a heating step at 110-130° C. for 2-4 hours.

20. The method for producing a PDMS valve-less micro pump according to claim 16, wherein said predetermined peripheral sealing way is a sealing way having supports at nodes of said PZT actuator.

21. The method for producing a PDMS valve-less micro pump according to claim 16, wherein said predetermined peripheral sealing way is a sealing way having supports at a periphery of said PZT actuator.

22. The method for producing a PDMS valve-less micro pump according to claim 16, wherein said predetermined peripheral sealing way is a sealing way having bonding at a periphery of said PZT actuator.

23. The method for producing a PDMS valve-less micro pump according to claim 16, wherein said “mounting a PZT actuator onto the membrane by a predetermined peripheral sealing way” is performed by coating a PDMS solution to a bottom of said PZT actuator.

Description:

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The invention relates to a valve-less micro pump structure and a method for producing the same, and more particularly to the structure that includes an elastomer main body made of polydimethylsiloxane (PDMS).

(2) Description of the Prior Art

In micro electric mechanical engineering, particularly that of biomedical field, micro fluid-detection and control components are crucial in utilization related to the precision automation industry. Among all the micro components, the micro pump as a fluid-control element is one of the key elements to make a micro fluid mechanism work.

In the art, micro pumps with micro valve structures are usually made of a silicon-base material by a semiconductor manufacturing process. These micro pumps often have the following weakness.

1. The semiconductor manufacturing process for producing the micro pumps cannot meet a rapid production requirement.

2. Cost for the silicon-base material for producing the micro pumps is high.

3. For the silicon-base material for producing the micro pumps is brittle, inherent problems in fatigue and pitting can never be neglected.

Also, it is well known that a brittle material is not suitable for application in the biomedical engineering.

4. The brittle silicon-base material for producing the micro pumps is vulnerable to impact and thus crack.

5. The silicon-base material for producing the micro pumps has poor bio-compatibility, and so limits the application of the micro electric mechanical components.

Therefore, to overcome various disadvantages from adopting the silicon-base material to the micro pumps by a semiconductor manufacturing process, a substitute material and an improved method for forming the micro pumps are definitely welcome to the skilled persons in the art.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a PDMS valve-less micro pump structure and a method for producing the same, in which the PDMS material is widely used to have the production of the micro pumps to be simply structured, low cost, flexible, and more bio-compatible.

The PDMS valve-less micro pump structure includes a PDMS body, a membrane, and a piezoelectric (PZT) actuator.

The PDMS body, as an elastomer made of a PDMS material, has a contour surface. The contour surface further is curved to form a main cavity, a lead-in cavity and a lead-out cavity. The lead-in cavity can be located aside to the main cavity and in spatial communication with the main cavity through a lead-in nozzle. Also, the lead-out cavity can be located also aside to the main cavity and in spatial communication with the main cavity through a lead-out nozzle.

The membrane having a center hole is layered on top of the PDMS body (i.e. on the contour surface) to seal the lead-in cavity, the lead-in nozzle, the lead-out nozzle and the lead-out cavity, but have the center hole positioned on top of the main cavity so as to expose the main cavity through the center hole.

The PZT actuator is mounted on top of the membrane by a predetermined peripheral sealing way that can seal the main cavity by covering the center hole of the membrane.

In one embodiment of the present invention, the membrane of the PDMS valve-less micro pump structure can be made of a PDMS material, and preferably have a thickness ranged between 200 μm and 300 μm.

In one embodiment of the present invention, the PZT actuator can further include a PZT plate, a copper plate layered under the PZT plate, an insulation layer sandwiched between the PZT plate and the copper plate to avoid electrically shorting in between, and a bottom layer layered under the copper plate to prohibit direct contact between the copper plate and a fluid in the main cavity. Preferably, the insulation layer and the bottom layer are both layers made of the PDMS material.

In one embodiment of the present invention, the predetermined peripheral sealing way to mount the PZT actuator onto the membrane can be a sealing way having supports at nodes of the PZT actuator, having supports at a periphery of the PZT actuator, or having bonding at the periphery of the PZT actuator.

In the present invention, the PDMS valve-less micro pump structure, i.e. the PDMS body as described above, can be produced in accordance with a method having the following steps of:

(1) Preparing a die, the die having a profiling protrusion forming on a top surface to configure concavely the main cavity, the lead-in cavity, the lead-in nozzle, the lead-out cavity, and the lead-out nozzle of the PDMS body;

(2) Pouring a PDMS material in a fluid state onto the top surface of the die by covering fully the profiling protrusion;

(3) Performing a predetermined baking process on the die and the PDMS material so as to solidify the PDMS material for forming the PDMS body; and

(4) Removing the solidified PDMS material from the die to complete the production of the PDMS body, i.e. the PDMS valve-less micro pump structure of the present invention.

In the present invention, the die for forming the PDMS body is preferably made of a polymethylmethacrylate (PMMA) material.

In one embodiment of the present invention, the fluid-state PDMS material for forming the PDMS body can be prepared by mixing a Sylgard 184 base (having short-chain PDMS molecules) and a Sylgard 184 agent at a 10:1 ratio. Preferably, the mixing can be achieved by blending the Sylgard 184 base and the Sylgard 184 agent in a magnetic stirrer for a predetermined period at a predetermined speed and then slowing the speed of the magnetic stirrer to de-bubble the PDMS material.

In one embodiment of the present invention, the predetermined baking process for solidifying the fluid-state PDMS material on the die can be a vacuum-baking process including a 20-30 minute low-pressure de-bubbling step, a heating step at 110-130° C. for 2-4 hours, and a free cooling step.

In the present invention, the PDMS valve-less micro pump can be produced by a method comprising the following steps of:

(1) Preparing the PDMS body, the PDMS body already having the main cavity, the lead-in cavity, the lead-in nozzle, the lead-out cavity and the lead-out nozzle formed concavely on the contour surface of the PDMS body;

(2) Adhering the membrane having the center hole onto the contour surface of the PDMS body by having the membrane seal the lead-in cavity, the lead-in nozzle, the lead-out nozzle and the lead-out cavity but having the center hole pf the membrane positioned on top of the main cavity;

(3) Mounting the PZT actuator onto the membrane by a predetermined peripheral sealing way so as to seal the main cavity that is exposed in the previous step; and

(4) Performing a baking process to solidify the combination of the PDMS body, the membrane, and the PZT actuator.

In one embodiment of the present invention, the predetermined baking process to confirm the combination among the PDMS body, the membrane and the actuator can be is a vacuum-baking process including a heating step at 110-130° C. for 2-4 hours.

All these objects are achieved by the PDMS valve-less micro pump structure and the method for producing the same described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be specified with reference to its preferred embodiment illustrated in the drawings, in which:

FIG. 1 is a perspective exploded view of a preferred embodiment of the PDMS valve-less micro pump in accordance with the present invention;

FIG. 2 is a flowchart showing a preferred method for producing the PDMS body in accordance with the present invention;

FIG. 3 is a flowchart showing a preferred method for producing the valve-less micro pump in accordance with the present invention;

FIG. 4 is a cross-sectional view of a preferred valve-less micro pump in accordance with the present invention;

FIG. 5 is an application state of FIG. 4;

FIG. 6 is another application state of FIG. 4;

FIG. 7 is a schematic view to show a predetermined sealing way for mounting the PZT actuator on the membrane in accordance with the present invention;

FIG. 8 is a schematic view to show another predetermined sealing way for mounting the PZT actuator on the membrane in accordance with the present invention;

FIG. 9 is a schematic view to show a further predetermined sealing way for mounting the PZT actuator on the membrane in accordance with the present invention; and

FIG. 10 is an enlarged cross-sectional view of the PZT actuator of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention disclosed herein is directed to a PDMS valve-less micro pump structure and a method for producing the same. In the following description, numerous details are set forth in order to provide a thorough understanding of the present invention. It will be appreciated by one skilled in the art that variations of these specific details are possible while still achieving the results of the present invention. In other instance, well-known components are not described in detail in order not to unnecessarily obscure the present invention.

Referring now to FIG. 1, a perspective exploded view of a preferred PDMS valve-less micro pump in accordance with the present invention is shown to mainly have a PDMS body 11, a membrane 12, and a PZT actuator 13.

The PDMS body 11 of the present invention is an elastomer that can be made of a PDMS material. The PDMS body 11 has a contour surface 110. As shown, the contour surface 110 is curved to form a main cavity 111, a lead-in cavity 113 and a lead-out cavity 112. The lead-in cavity 113 can be located aside (for example, left-hand side in the figure) to the main cavity 111 and be in spatial communication (or say, in a channel-wise connection) with the main cavity 111 through a lead-in nozzle 115 also formed in the PDMS body 11. Similarly, the lead-out cavity 112 can be located aside (for example, right-hand side in the figure) to the main cavity 111 and in spatial communication with the main cavity 111 through a lead-out nozzle 114 formed in the PDMS body 11.

In the present invention, the PDMS material is an elastic polymer featuring in hydrophilic and transparent property. The contact angle between a PDMS molecule and a water molecule is about 108 degree. For having an acceptable bio-compatibility, the PDMS material is much suitable for producing the bio-medical components. The PDMS material has an excellent electric-insulation property and a damper property to absorb any foreign impact. Also, the dielectric strength of the PDMS material is also acceptable to most applications. Importantly, the aforesaid properties of the PDMS material can be maintained under any environmental temperature and moisture situation.

The PDMS material itself is an inertial material that is damp to the O3 and the ultraviolet ray. Yet, the PDMS material can be easily adhered to an ordinary smooth surface, for example a surface of a silicon wafer, a glass, or a PMMA object.

As shown in FIG. 1, the lead-in cavity 113 and the lead-out cavity 112 are located to opposite sides of the main cavity 111. However, such an arrangement doesn't imply that the present invention prohibits other arrangements of the lead-in cavity 113 and the lead-out cavity 112 with respect to the main cavity 111. Basically, any arrangement that separates the lead-in cavity 113 from the lead-out cavity 112 around the main cavity 111 can be acceptable to the present invention.

As shown, an end of the lead-in nozzle 115 that has a larger cross section is connected with the lead-in cavity 113, while another end having a smaller cross section is connected with the main cavity 111. On the other hand, the end of the lead-out nozzle 114 that has a larger cross section is connected with the main cavity 111, while another end having a smaller cross section is connected with the lead-out cavity 112.

In FIG. 1, the membrane 12 of the present invention for adhering or layering on the contour surface 110 of the PDMS body 11 has a center hole 121. The membrane 12 is used to seal or cover the lead-in cavity 113, the lead-in nozzle 115, the lead-out nozzle 114 and the lead-out cavity 112 so that the curved-in structures of the lead-in cavity 113, the lead-in nozzle 115, the lead-out nozzle 114 and the lead-out cavity 112 can be formed as flow channel structures. Also, it is noted that the main cavity 111 is still exposed to the membrane 12 by having the center hole 121 of the membrane 12 positioned right on top of the main cavity 111.

In the present invention, the membrane 12 is preferably made of a PDMS material, and preferably has a thickness ranged between 200 μm and 300 μm.

The PZT actuator 13 of the present invention is mounted on top of the membrane 12 by a predetermined peripheral sealing way that can seal the main cavity 111 by sitting on or covering the center hole 121 of the membrane 12.

Referring now to FIG. 2, a flowchart for a preferred method for producing the PDMS body 11 is shown. The method can include the following steps.

Step 100: Preparing a die 14. The die 14 has a profiling protrusion 141 forming on a top surface of the die 14. By properly providing the profiling protrusion 141, the aforesaid concave structures of the PDMS body 11 such as the main cavity 111, the lead-in cavity 113, the lead-in nozzle 115, the lead-out cavity 112, and the lead-out nozzle 114 can be formed by the following molding.

Step 200: Pouring a PDMS material in a fluid state 11 onto the top surface of the die 14 by covering fully the profiling protrusion 141.

Step 300: Performing a predetermined baking process on the assembly of the die 14 and the PDMS material 11 so as to solidify the PDMS material 11 for forming the aforesaid PDMS body 11.

Step 400: Removing the solidified PDMS material 11 from the die 14 to complete the production of the PDMS body 11 for the PDMS valve-less micro pump of the present invention.

In the present invention, the die 14 for forming or molding the PDMS body 11 is preferably made of a PMMA material.

In the present invention, the PDMS material can be obtained in a Sylgard 184 Silicone Elastomer Kit provided by the Dow Coing Company in the United States. In this kit, the PDMS material for molding the PDMS body 11 can be prepared by mixing a Sylgard 184 base (having short-chain PDMS molecules) and a Sylgard 184 agent at a 10:1 ratio. Preferably, the mixing can be performed by blending the Sylgard 184 base and the Sylgard 184 agent in a magnetic stirrer for a predetermined period at a predetermined speed and then slowing the speed of the magnetic stirrer to de-bubble the fluid-state PDMS material.

In the present invention, the predetermined baking process for solidifying the fluid-state PDMS material 11 molded on the die 14 can be a vacuum-baking process that includes a 20-30 minute low-pressure de-bubbling step, a heating step at 110-130° C. for 2-4 hours, and a free cooling step for cooling down the PDMS material 11 to the room temperature.

Referring now to FIG. 3, a flowchart for a preferred method for producing the PDMS valve-less micro pump in accordance with the present invention is shown. The method comprises the following steps.

Step 500: Preparing the PDMS body 11. The PDMS body 11 already has the main cavity 111, the lead-in cavity 113, the lead-in nozzle 115, the lead-out cavity 112 and the lead-out nozzle 114 formed concavely on the contour surface 110 of the PDMS body 11.

Step 600: Adhering the membrane 12 having the center hole 121 onto the contour surface 110 of the PDMS body 11. The adhering is done by having the membrane 12 seal the lead-in cavity 113, the lead-in nozzle 115, the lead-out nozzle 114 and the lead-out cavity 112, but having the center hole 121 of the membrane 12 positioned on top of the main cavity 111.

Step 700: Mounting the PZT actuator 13 on the membrane 12 by a predetermined peripheral sealing way. Thereby, the main cavity 111 can be sealed by the PZT actuator 13 and thus form as a central tank of the fluid channel that includes in series the lead-in cavity 113, the lead-in nozzle 115, the main cavity 111, the lead-out nozzle 114 and the lead-out cavity 112.

Step 800: Performing a baking process to solidify the combination of the PDMS body 11, the membrane 12, and the PZT actuator 13. After the baking, a production of the PDMS valve-less micro pump according to the present invention is done.

In the present invention, the predetermined baking process to confirm the combination among the PDMS body 11, the membrane 12 and the actuator 13 can be also is a vacuum-baking process including a heating step at 110-130° C. for 2-4 hours.

Referring now to FIG. 4, a cross-section view of a preferred PDMS valve-less micro pump along line a-a of FIG. 1 is shown, in which the lead-in nozzle 115 and the lead-out nozzle 114 are not shown. In FIG. 4, a lead-in channel 116 and a lead-out channel 117 are constructed under the lead-in cavity 113 and the lead-out cavity 112, respectively. The lead-in channel 116 is provided so that a fluid outside the PDMS body 11 can be sent into and/or out off the lead-in cavity 113. Similarly, the lead-out channel 117 is there so that the fluid outside the PDMS body 11 can be sent into and/or out off the lead-out cavity 112.

In the present invention, for the PDMS material is a soft elastomer, the forming of the lead-in channel 116 and the lead-out channel 117 can be directly done by piecing a needle or a like piecing structure into the PDMS body 11 at the application site of the micro pump. This channel-forming work is well known to a skilled person in the related art, and so details will be omitted herein.

As shown in FIG. 4, before the PDMS valve-less micro pump of the present invention works, proper wiring 15 should also be established between the actuator 13 and a foreign power device (not shown in the figure). Thereby, the PZT actuator 13 can thus be controlled to perform its up-and-down action upon the main cavity 111.

Referring now to FIG. 5, a down (or concave) state of the PZT actuator 13 is shown by a dashed line 13′. In this state, the PZT actuator 13 is controlled to present a concave configuration 13′ so as to depress the main cavity 111 or say to reduce the volume inside the main cavity 111. Thereby, the fluid inside the main cavity 111 would be squeezed out to both the lead-in cavity 113 and the lead-out cavity 112 through the lead-in nozzle 115 and the lead-out nozzle 114, respectively. For the directional arrangement of the nozzles 114 and 115 (referred to FIG. 1), the fluid amount qo leaving the main cavity 111 through the lead-in nozzle 1115, the lead-in cavity 113 and the lead-in channel 116 would be less than the fluid amount Qo leaving the main cavity 111 through the lead-out nozzle 114, the lead-out cavity 112 and the lead-out channel 117.

Referring now to FIG. 6, an up (or convex) state of the PZT actuator 13 is shown by another dashed line 13″. In this state, the PZT actuator 13 is controlled to present a convex configuration 13″ so as to dilate the main cavity 111 or say to suddenly enlarge the volume inside the main cavity 111. Thereby, the fluid in the lead-in cavity 113 and the lead-out cavity 112 would be sucked into the main cavity 111 through the lead-in nozzle 115 and the lead-out nozzle 114, respectively. For the directional arrangement of the nozzles 114 and 115 (referred to FIG. 1), the fluid amount qin entering the main cavity 111 through the lead-in channel 116, the lead-in cavity 113 and the lead-in nozzle 115 would be larger than the fluid amount Qin entering the main cavity 111 through the lead-out channel 117, the lead-out cavity 112 and the lead-out nozzle 114.

In the present invention, after an operational stroke of the PZT actuator 13 (including a down state and an up state), a preset amount of the fluid, (Qo-Qin) or (qin-qo), can then be transported from the lead-in channel 116 to the lead-out channel 117 of the PDMS body 11.

In the present invention, the PZT actuator 13 is fixed air-tightly onto the membrane 12 through the predetermined peripheral sealing way. In practice, the predetermined peripheral sealing way can be a sealing way as shown in FIG. 7 that provides annular supports 132 at nodes 131 of the PZT actuator 13, a sealing way as shown in FIG. 8 that provides annular supports 132 at a periphery 133 of the PZT actuator 13, or a sealing way as shown in FIG. 9 that provides annular bonding 132 at the periphery 133 of the PZT actuator 13. It should be noted that different sealing ways would cause different state appearance of the PZT actuator 13. However, for the supports 132 in all three cases stand on the membrane 12, so different sealing ways of the PZT actuator 13 can only render minor difference in state appearance of the PZT actuator 13. That is to say that the configuration of the PZT actuator 13 shown in FIG. 5 or FIG. 6 can still prevail no matter what kind of the sealing way is applied.

Referring now to FIG. 10, an enlarged cross-sectional view of the PZT actuator 13 of the present invention is shown. The PZT actuator 13 can include a PZT plate 134 and a copper plate 136 layered under the PZT plate 135. In operation, for the PZT plate 134 and the copper plate 135 need to connect with respective electrodes 138 so as to act as a positive end and a negative end, respectively, so an insulation layer 136 is introduced to be sandwiched between the PZT plate 134 and the copper plate 135 for avoiding possible electrically shorting in between. On the other hand, to prevent the copper plate 135 from directly contacting the fluid in the main cavity 111 of the PDMS body 11, a bottom layer 137 coated or layered under the copper plate 135 is provided to prohibit such direct contact between the copper plate 135 and a fluid in the main cavity 111.

Preferably in the present invention, both the insulation layer 136 and the bottom layer 137 can be made of the PDMS material. By introducing the elastic PDMS material to wrap the copper plate 135 in a thin layer wise, the copper plate 135 can then have better flexibility to satisfy the concave and convex operations of the PDMS valve-less micro pump. Thereby, the throughput of the PDMS valve-less micro pumps can be increased.

In the present invention, prior to mounting the PZT actuator 13 onto the membrane 12, the bottom of the PZT actuator 13 can be brushed and thus coat a layer of a PDMS solution for adhering the PZT actuator 13.

In the present invention, for all the inner surfaces of the formed channel structures in the PDMS body are made as PDMS surfaces, the applicability of the PDMS valve-less micro pumps in the biomedical or chemical industry can be increased.

By providing the PDMS valve-less micro pump structure and the molding method for producing the same in accordance with the present invention, the production of the micro pumps can be simply, low cost, and flexible, and the product can be more bio-compatible.

While the present invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be without departing from the spirit and scope of the present invention.