TW201825780A - Micro-fluid control device - Google Patents

Abstract

A micro-fluid control device is disclosed and comprises an actuator and a case, the actuator comprises a square suspension plate, a frame, at least one supporting part and an anti-overflow structure, wherein the supporting part is connected to the square suspension plate and the frame, and the square suspension plate, the frame and a first surface of the supporting part are coplanar, and the anti-overflow structure is disposed between the frame and a second surface of the supporting part for keeping a height difference between the frame and the supporting part. By the anti-overflow structure of the present invention, the overflow of colloid during coating a colloid layer on the frame can be avoided.

Description

Microfluidic control device

The present invention relates to a fluid control device, and more particularly to a miniature ultra-thin and silent microfluidic control device.

At present, in various fields, such as medicine, computer technology, printing, energy and other industries, the products are developing in the direction of refinement and miniaturization. Among them, products such as micro-pumps, sprayers, inkjet heads, industrial printing devices, etc. The fluid transport structure is its key technology, which is how to break through its technical bottleneck with innovative structure and be an important part of development.

For example, in the pharmaceutical industry, many instruments or equipment that require pneumatic power drive are usually used with conventional motors and pneumatic valves to achieve their fluid delivery. However, limited by the volume limitations of conventional motors and fluid valves, it is difficult for such instruments to reduce the size of their overall devices, that is, it is difficult to achieve the goal of thinning, and it is impossible to achieve portable purposes. In addition, these conventional motors and fluid valves also cause noise problems when they are actuated, resulting in inconvenience and discomfort in use.

As shown in FIG. 1, a fluid control device includes a housing 1 and a piezoelectric actuator 2, two insulating sheets 3a and 3b, and a conductive sheet 4. The housing 1 includes an outlet plate 11 and a base 12. The outlet plate 11 has a frame structure having a side wall 111 at the periphery and a plate member 112 at the bottom, and the side wall 111 and the plate member 112 define a housing together. a space 113 for the piezoelectric actuator 2 to be disposed in the accommodating space 113, wherein the plate member 112 is recessed on a surface to form a temporary storage chamber 114, and at least one of the plate member 112 is disposed on the plate member 112. The discharge hole 115 is connected to the temporary storage chamber 114. The base 12 includes an inlet plate 121 and a resonant plate 122. The inlet plate 121 has at least one inlet hole 1211, at least one bus bar groove 1212 and a confluence chamber 1213. The inlet hole 1211 is correspondingly connected to the bus bar slot 1212, and the other end of the at least one bus bar slot 1212 is connected to the confluence chamber 1213. The confluence chamber 1213 forms a chamber for the confluent fluid for temporarily suspending the fluid. The cavity is formed to have the same depth as the bus bar 1212, and the resonator piece 122 is a flexible material having a hollow hole 1223 corresponding to the confluence chamber 1213 of the inlet plate 121. So that the fluid of the confluence chamber 1213 can pass through the hollow hole 1223 flows to the lower side of the resonator piece 122. Thus, an outlet plate 11, an insulating sheet 3b, a conductive sheet 4, an insulating sheet 3a, a piezoelectric actuator 2, and a base 12 are sequentially stacked and fixed, and finally the side walls 111 of the outlet plate 11 are accommodated on both sides. The space 113 is coated with a sealant 6 to provide a leakproof seal and is provided to form a fluid control device. Thus, the fluid control device has a simple structure and can be configured to be thin.

Further, the piezoelectric actuator 2 is disposed corresponding to the resonator piece 122, and is composed of a suspension plate 21, a piezoelectric element 22, an outer frame 23, and at least one bracket 24, and the resonance piece 122 is movable corresponding to the confluence chamber 1213. The portion 1221 is fixedly bonded to the base 12 as a fixing portion 1222.

The equipment to which the above-described assembled fluid control device is applied is always in a trend of miniaturization. Therefore, it is required to further reduce the size of the fluid control device without reducing the output capacity (discharge flow rate and discharge pressure) of the fluid control device. However, the smaller the fluid control device described above, the lower the output capability of the fluid control device. Therefore, if the control output capability is to be maintained and miniaturized, there is a limit in the above-described control of the existing structure. Therefore, the present invention has studied the control of the structure shown below.

Fig. 1 is a cross-sectional view showing the configuration of a main part of the fluid control device. The fluid control device is a structure in which an outlet plate 11, an insulating sheet 3b, a conductive sheet 4, an insulating sheet 3a, a piezoelectric actuator 2, and a base 12 are sequentially stacked and fixed.

However, a glue layer 5 is disposed between the outer frame 23 of the suspension plate 21 and the resonance plate 122. When the glue layer 5 is applied, the frame 23 is subjected to the capillary action of the outer frame 23 because the glue layer 5 is applied to the piezoelectric actuation. The relationship is such that the glue layer 5 flows along the outer frame 23 toward the bracket 24, so that the flow easily overflows the outer frame 23 and adheres to the bracket 24, causing the bracket 24 and the resonator piece 122 to adhere to the glue layer 5, In turn, the resonance effect of the resonant plate 122 and the bracket 24 is affected, so that the working efficiency of the fluid control device is affected, or the flow of the rubber layer 5 into the microfluidic control device may affect the operation of other components, and it is necessary to improve.

Therefore, how to develop a micro-pneumatic fluid device capable of improving the above-mentioned conventional technology and making the instrument or device using the conventional fluid control device small, miniaturized and muted, thereby achieving a portable and portable purpose Electric actuators are an urgent problem to be solved.

The main purpose of the present invention is to provide a microfluidic control device, which is provided with an overflow prevention structure on the second surface of the outer frame near the second surface of the bracket, so that the outer frame and the bracket maintain a height difference to suppress the glue layer overflow. Glue problem.

In order to achieve the above object, a broader embodiment of the present invention provides a microfluidic control device comprising a piezoelectric actuator and a housing, the piezoelectric actuator comprising: a suspension plate having a first a surface and a corresponding second surface, and the second surface has a convex portion; an outer frame disposed around the outer side of the suspension plate and having a first surface and a corresponding second surface, The first surface of the suspension plate is coplanar with the first surface of the outer frame; at least one bracket is connected between the suspension plate and the outer frame, and has a first surface and a corresponding second surface. The first surface of the bracket is coplanar with the first surface of the outer frame; at least one overflow prevention structure is formed between the outer frame and the bracket to maintain a height difference between the outer frame and the bracket; a piezoelectric ceramic plate attached to the first surface of the suspension plate; and the housing includes: an outlet plate having a side wall having a side wall to form a receiving space, so that The piezoelectric actuator is disposed in the accommodating space; and a a seat, which is formed by joining an inlet plate and a resonating plate, and is coupled to the accommodating space of the outlet plate to close the piezoelectric actuator, the inlet plate having at least one air inlet and connected thereto Passing at least one bus bar hole to form a bustling chamber, the resonator piece is fixedly fixed to the inlet plate, and has a hollow hole opposite to the confluence chamber of the inlet plate and corresponding to the suspension plate a convex portion; wherein a second layer of the piezoelectric actuator outer frame and the resonant plate of the base are disposed between the piezoelectric actuator and the resonant plate of the base A depth is maintained to form a compression chamber, and the height difference of the overflow structure is sufficient to fill the overflow layer to inhibit the glue layer from overflowing the frame.

A generalized embodiment of the present invention provides a piezoelectric actuator comprising: a suspension plate having a first surface and a corresponding one of the second surfaces, and the second surface has a convex portion; The outer frame is disposed on the outer side of the suspension plate and has a first surface and a corresponding second surface, the first surface of the suspension plate being coplanar with the first surface of the outer frame; at least one bracket Connecting between the suspension plate and the outer frame, and having a first surface and a corresponding second surface, the first surface of the bracket being coplanar with the first surface of the outer frame; at least one An overflow structure is formed between the second surface of the outer frame and the second surface of the bracket to maintain a height difference between the outer frame and the bracket; and a piezoelectric ceramic plate attached to the suspension plate On the first surface.

Some exemplary embodiments embodying the features and advantages of the present invention are described in detail in the following description. It is to be understood that the present invention is capable of various modifications in various aspects, and is not to be construed as a limitation.

As shown in FIG. 1 , FIG. 2A , FIG. 2B and FIG. 3 , the fluid control device of the present invention comprises a housing 1 , a piezoelectric actuator 2 , two insulating sheets 3 a , 3 b and a conductive sheet 4 . The housing 1 includes an exit plate 11 and a base 12, and the base 12 includes an inlet plate 121 and a resonant plate 122, but is not limited thereto. The piezoelectric actuator 2 is disposed corresponding to the resonator piece 122, and the outlet plate 11, the piezoelectric actuator 2, and the resonance plate 122 of the base 12, the inlet plate 121, and the like are sequentially stacked upward, and piezoelectrically actuated. The device 2 is assembled from a suspension plate 21, a piezoelectric element 22, an outer frame 23, and at least one bracket 24.

In the present embodiment, the exit plate 11 of the housing 1 has a frame structure having a side wall 111 at the periphery and a plate member 112 at the bottom, and an accommodating space 113 is defined by the side wall 111 and the plate member 112 for The piezoelectric actuator 2 is disposed in the accommodating space 113, and the plate member 112 is recessed on a surface to form a temporary storage chamber 114, and the plate member 112 is provided with at least one discharge hole 115 extending through the temporary storage. The accommodating space 113 is defined by the side wall 111 and the plate member 112 for the piezoelectric actuator 2 to be disposed in the accommodating space 113. The base 12 includes an inlet plate 121 and a resonant plate 122. The inlet plate 121 has at least one access hole 1211. In this embodiment, the number of the access holes 1211 is four, but not limited thereto. The upper surface of the inlet plate 121 is mainly for allowing fluid to flow from the at least one inlet hole 1211 into the fluid control device from the outside of the device, and the inlet plate 121 has at least one bus bar groove 1212, each confluence The trough 1212 is disposed to communicate with an access hole 1211. The center of the bus bar 1212 has a confluence chamber 1213, and the confluence chamber 1213 communicates with the bus trough 1212. A fluid entering the orifice 1211 entering the busbar groove 1212 is directed and confluently concentrated to the confluence chamber 1213.

In the present embodiment, the inlet plate 121 has an integrally formed inlet hole 1211, a bus bar groove 1212, and a confluence chamber 1213. When the inlet plate 121 is assembled corresponding to the resonator piece 122, a confluence is formed at the confluence chamber 1213. a chamber of fluid for temporary storage of fluid.

In some embodiments, the material of the inlet plate 121 is made of stainless steel, but is not limited thereto. In other embodiments, the depth of the chamber formed by the confluence chamber 1213 is the same as the depth of the busbar slots 1212, but is not limited thereto.

Further, the piezoelectric actuator 2 described above is provided corresponding to the resonator piece 122, and is composed of a suspension plate 21, a piezoelectric element 22, an outer frame 23, and at least one bracket 24, and the resonance piece 122 corresponds to the confluence chamber 1213. The movable portion 1221 is fixedly bonded to the base 12 as a fixed portion 1222, and has a hollow hole 1223 on the resonant plate 122 corresponding to the confluence chamber 1213 of the inlet plate 121 to allow fluid to flow. In this embodiment, the resonator piece 122 is a flexible material, but is not limited thereto. In other embodiments, the resonant plate 122 is made of a copper material, but is not limited thereto.

The piezoelectric element 22 described above has a square plate-like structure, and its side length is not larger than the side length of the suspension plate 21, and can be attached to the suspension plate 21. In the present embodiment, the suspension plate 21 is a flexible square plate-like structure, and the outer frame 23 is disposed around the outer side of the suspension plate 21. The shape of the outer frame 23 also substantially corresponds to the shape of the suspension plate 21. In the present embodiment, the outer frame 23 is also a square hollow frame structure; and the suspension plate 21 and the outer frame 23 are connected by four brackets 24 and provide elastic support. Please refer to FIG. 2A and FIG. 2B at the same time, the suspension plate 21, the outer frame 23 and the four brackets 24 are integrally formed, and may be composed of a metal plate, for example, may be made of stainless steel, but not For this reason, the piezoelectric actuator 2 of the fluid control device of the present invention is formed by bonding the piezoelectric element 22 to the metal plate, but is not limited thereto. The outer frame 23 is disposed on the outer side of the suspension plate 21 and has an outwardly protruding conductive pin 231 for power connection, but not limited thereto; and the four brackets 24 are connected to the suspension plate 21 and Between the outer frames 23 to provide elastic support. In this embodiment, one end of each of the brackets 24 is connected to the side of the suspension plate 21, and the other end is connected to the inner side of the outer frame 23, and between the bracket 24, the suspension plate 21 and the outer frame 23. There is at least one gap 25 for fluid circulation, and the type and number of the suspension plate 21, the outer frame 23 and the bracket 24 are varied. Through the bracket 24 disposed between the suspension plate 21 and the outer frame 23, the uneven angle of the suspension plate 21 during operation is reduced, which helps to increase the amplitude of the suspension plate 21 on the Z-axis, so that the suspension plate 21 can have a better displacement state when vibrating up and down, that is, the suspension plate 21 is more stable and consistent when it is actuated, which is beneficial to improve the stability and performance of the piezoelectric actuator 2. In this embodiment, the suspension plate 21 is a square and has a stepped surface structure, that is, a surface of the suspension plate 21 has a convex portion 26, and the convex portion 26 can be a circular convex structure, but Not limited to this.

Further, the two insulating sheets 3a and 3b are provided with the conductive sheets 4 interposed therebetween. In addition, in some embodiments, the insulating sheets 3a, 3b are made of an insulating material, such as plastic, but not limited thereto for insulation; in other embodiments, the conductive sheets 4 are electrically conductive. Material, for example: metal, but not limited to it for electrical conduction. Moreover, in the embodiment, a conductive pin 41 may be disposed on the conductive sheet 4 for electrical conduction.

When the fluid control device of the present invention is assembled, the structure of the outlet plate 11, an insulating sheet 3b, a conductive sheet 4, an insulating sheet 3a, a piezoelectric actuator 2, and a base 12 are stacked and assembled upward. And is disposed in the accommodating space 113 of the outlet plate 11. Finally, the accommodating space 113 is disposed on both sides of the side wall 111 of the outlet plate 11 to provide a leakproof seal to form a small flow volume and a miniaturized shape. Fluid control device. In the above configuration, when the driving voltage is applied to the piezoelectric element 22, the suspension plate 21 is bent and vibrated by the expansion and contraction of the piezoelectric element 22, and the movable portion 1221 of the resonance piece 122 is vibrated by the vibration of the suspension plate 21, The fluid control device draws fluid from at least one of the access holes 1211 of the base 12, and the fluid flows into the at least one bus bar 1212 and flows into the confluence chamber 1213 through the hollow hole 1223 into the temporary storage chamber 114. The suspension plate 21 of the piezoelectric actuator 2 vibrates and the resonance effect of the resonance plate 122 compresses the volume of the temporary storage chamber 114, and is discharged from at least one discharge hole 115 of the outlet plate 11 to constitute a fluid control device for transferring fluid. .

Further, as shown in FIGS. 1 and 3, the resonator piece 122 and the piezoelectric actuator 2 have a gap h between the resonator piece 122 and the outer frame 23 of the piezoelectric actuator 2 in the gap h. The filling layer 5 is provided, for example, a conductive adhesive, but not limited thereto, so that the depth of the gap h can be maintained between the resonant plate 122 and the suspension plate 21 of the piezoelectric actuator 2, thereby guiding the airflow. Flowing more rapidly; and, in response to the depth of the gap h, a compression chamber 116 can be formed between the resonator piece 122 and the piezoelectric actuator 2, and the fluid can be guided to the chamber through the hollow hole 1223 of the resonator piece 122. The flow flows more rapidly, and since the suspension plate 21 and the resonator piece 122 are kept at an appropriate distance, the mutual contact interference is reduced, and the noise generation can be reduced.

In addition, in order to improve the adhesion between the frame 23 and the resonator piece 122 outside the suspension plate 21, when the glue layer 5 is applied, the glue layer 5 is applied to the piezoelectrically actuated frame 23 and is subjected to the capillary action of the frame 23. The adhesive layer 5 is caused to flow along the outer frame 23 toward the bracket 24, so that the flow easily overflows the outer frame 23 and adheres to the bracket 24, etc., so that the structure of the outer frame 23 of the piezoelectric actuator 2 is further improved. The second surface 23b of the frame 23 is disposed adjacent to the second surface 24b of the bracket 24 with an overflow preventing structure 27 (as shown in FIG. 4A). The overflow preventing structure 27 is formed by etching to form a notch or anti-blocking convex portion. The overflow of the glue layer 5 can utilize the overflow prevention structure 27 to suppress the problem of the glue layer 5 overflowing.

As shown in FIG. 4A and FIG. 5, the piezoelectric actuator 2 of the present invention comprises: a suspension plate 21 having a first surface 21a and a second surface 21b corresponding to the first surface 21a, and a second The surface 21b has a convex portion 26; an outer frame 23 is disposed on the outer side of the suspension plate 21, and has a first surface 23a and a second surface 23b corresponding to the first surface 23a. The first surface 21a is coplanar with the first surface 23a of the outer frame; at least one bracket 24 is connected between the suspension plate 21 and the outer frame 23, and has a first surface 24a and a corresponding surface of the first surface 24a. The second surface 24b, the first surface 24a of the bracket is coplanar with the first surface 23a of the outer frame; at least one overflow preventing structure 27 is formed between the outer frame 23 and the bracket 24 to keep the outer frame 23 and the bracket 24 a height difference; and a piezoelectric ceramic plate 22 attached to the first surface 21a of the suspension plate.

As shown in FIG. 4A, FIG. 4B and FIG. 5, in the first embodiment, the overflow prevention structure 27 is formed at the edge of the outer frame 23 connecting the bracket 24 and extending toward the second surface 24b of the outer frame 23 to form a The first differential surface 28a, the first differential surface 28a and the second surface 23b of the outer frame maintain a first overflow depth s1, and the first differential surface 28a forms a coplanar abutment with the second surface 24b of the bracket 24, such that The overflow preventing structure 27 can be connected to the bracket 24 by the edge and extends to the second surface 24b to form a space of the first step surface 28a and the first overflow depth s1 to fill the glue layer 5, thereby inhibiting the glue layer 5 overflowing. Glue problem.

As shown in FIG. 6, in the second embodiment, the overflow prevention structure 27 is formed at the edge of the outer frame 23 connecting the bracket 24 and extending toward the second surface 24b of the outer frame 23 to form a second step surface 28b. The surface 28b and the second surface 23b of the outer frame 23 maintain a second overflow depth s2, the second step surface 28b and the second surface 23b of the bracket 23 maintain a third overflow depth s3, and the second overflow depth s2 More than the third overflow depth s3, such a space of the second step surface 28b and the second overflow depth s2 to fill the glue layer 5, and the third overflow depth s3 provides a further anti-overflow effect, blocking glue The overflow of the layer 5 flows along the direction of the bracket 24, which can also inhibit the problem of the glue layer 5 overflowing.

As shown in FIG. 7, in the third embodiment, the overflow prevention structure 27 is disposed at the edge of the outer frame 23 and is connected to the bracket 24 and extends in the direction of the second surface 24b of the outer frame 23 to form an overflow preventing recess 27a and an overflow preventing convex portion. In the portion 27b, the overflow preventing recess 27a is adjacent to the outer frame 23, and the overflow preventing convex portion 27b is adjacent to the overflow preventing recess portion 27a. The overflow preventing concave portion 27a has a third step surface 28c and a second surface 23b of the outer frame 23 to maintain a fourth overflow prevention portion. The depth s4, and the top surface of the overflow preventing projection 27b is coplanar with the second surface 23b of the outer frame 23, and maintains a fifth overflow depth s5 with the bracket 24. The space of the third step surface 28c and the fourth overflow prevention depth s4 formed by the overflow preventing recess 23a of the present example fills the overflow of the adhesive layer 5, and the fifth overflow prevention depth s5 of the overflow preventing convex portion 27b provides better The anti-overflow effect, the overflow glue of the barrier rubber layer 5 flows along the direction of the bracket 24, and can also inhibit the glue layer 5 overflowing problem.

In addition to the overflow prevention structure 27 of the above embodiment, in the fourth embodiment, the overflow prevention structure 27 may also be disposed at the edge of the outer frame 23 connecting the bracket 24 and extending in the direction of the second surface 24b of the outer frame 23 to form a loop type. In addition, as shown in FIGS. 8A and 8B, the overflow prevention structure 27 is connected to the bracket 24 at the edge of the outer frame 23 and extends to the second surface 24b of the outer frame 23 to form a loop shape. a fourth differential surface 28d, the fourth differential surface 28d and the second surface 23b of the outer frame 23 maintain a sixth overflow depth s6, and the fourth differential surface 28d forms a second surface 24b of the bracket 24. Coplanar abutment. The overflow structure 27 thus disposed can be connected to the bracket 24 by the edge and extends to the second surface 24b to form a fourth step surface 28d and a sixth overflow depth s6 to fill the glue layer 5 In addition, the glue layer 5 is inhibited from overflowing.

In summary, the present invention provides a microfluidic control device, which is provided with an anti-overflow structure on the second surface of the outer frame near the second surface of the bracket to suppress the glue overflow problem, and the miniaturized piezoelectric The actuator can reduce the overall volume of the microfluidic control device and reduce the thickness thereof, so as to achieve the portable and portable purpose; therefore, the microfluidic control device of the present invention has great industrial utilization value and is applied according to law.

The present invention has been described in detail by the above-described embodiments, and is intended to be modified by those skilled in the art.

1‧‧‧shell

11‧‧‧Export board

111‧‧‧ side wall

112‧‧‧ boards

113‧‧‧ accommodating space

114‧‧‧Storage chamber

115‧‧‧Exhaust hole

116‧‧‧Compression chamber

12‧‧‧Base

121‧‧‧ entrance board

1211‧‧‧ access hole

1212‧‧‧ busbar slot

1213‧‧‧Confluence chamber

122‧‧‧Resonance film

1221‧‧‧movable department

1222‧‧‧Fixed Department

1223‧‧‧ hollow holes

2‧‧‧ Piezoelectric Actuator

21‧‧‧suspension board

21a‧‧‧The first surface of the suspension plate

21b‧‧‧Second surface of the suspension plate

22‧‧‧Piezoelectric components

23‧‧‧Front frame

23a‧‧‧The first surface of the frame

23b‧‧‧Second surface of the outer frame

231‧‧‧Electrical pins

24‧‧‧ bracket

24a‧‧‧ first surface of the bracket

24b‧‧‧Second surface of the bracket

25‧‧‧ gap

26‧‧‧ convex

27‧‧‧Overflow prevention structure

27a‧‧‧Overflow recess

27b‧‧‧Anti-overburst

28a‧‧‧ first paragraph

28b‧‧‧The second paragraph

28c‧‧‧The third paragraph

28d‧‧‧The fourth paragraph

3a, 3b‧‧ ‧ insulating sheet

4‧‧‧Conductor

41‧‧‧Electrical pins

5‧‧‧ glue layer

6‧‧‧Packing

H‧‧‧ gap

S1‧‧‧First overflow depth

S2‧‧‧Second overflow prevention depth

S3‧‧‧ third overflow depth

S4‧‧‧Fourth overflow prevention depth

s5‧‧‧The fifth overflow prevention depth

S6‧‧‧ sixth overflow depth

Figure 1 is a schematic cross-sectional view of the fluid control device. Figure 2A shows an exploded front view of the fluid control device related components. Figure 2B is a schematic exploded perspective view of the fluid control device associated components. Figure 3 is a schematic cross-sectional view showing the piezoelectric actuator assembled on the base. Fig. 4A is a schematic perspective view showing the front view of the piezoelectric actuator. Fig. 4B is a perspective view showing the stereoscopic appearance of the piezoelectric actuator on the back side. Figure 5 is a schematic cross-sectional view showing a first embodiment of the overflow prevention structure of the fluid control device. Figure 6 is a schematic cross-sectional view showing a second embodiment of the overflow prevention structure of the fluid control device. Figure 7 is a schematic cross-sectional view showing a third embodiment of the overflow prevention structure of the fluid control device. Fig. 8A is a perspective view showing the appearance of the fourth embodiment of the overflow control structure of the fluid control device. Figure 8B is a schematic cross-sectional view showing a fourth embodiment of the overflow prevention structure of the fluid control device.

Claims (10)

A microfluidic control device comprising: a piezoelectric actuator comprising: a suspension plate having a first surface and a corresponding one of the second surfaces, the second surface having a convex portion; an outer frame surrounding An outer surface of the suspension plate has a first surface and a corresponding second surface, the first surface of the suspension plate being coplanar with the first surface of the outer frame; at least one bracket connected to the Between the suspension plate and the outer frame, and having a first surface and a corresponding second surface, the first surface of the bracket is coplanar with the first surface of the outer frame; at least one overflow prevention structure Between the outer frame and the bracket to maintain a height difference between the outer frame and the bracket; and a piezoelectric ceramic plate attached to the first surface of the suspension plate; and a casing comprising: An outlet plate having a side wall and a bottom portion having a plate member to form a frame structure of the accommodating space, the piezoelectric actuator being disposed in the accommodating space; and a base An entrance board And a resonant piece is joined and coupled in the accommodating space of the outlet plate to close the piezoelectric actuator, the inlet plate has at least one air inlet hole and at least one bus bar connected thereto a hole, to form a confluence chamber, the resonating plate is fixedly fixed to the inlet plate, and has a hollow hole opposite to the confluence chamber of the inlet plate and corresponding to the convex portion of the suspension plate; An adhesive layer is disposed between the second surface of the outer frame of the piezoelectric actuator and the resonant piece of the base to maintain a depth between the piezoelectric actuator and the resonant plate of the base to form a A compression chamber, the height difference of the overflow prevention structure is used to fill the overflow layer of the glue layer to inhibit the glue layer from overflowing the outer frame. The microfluidic control device of claim 1, wherein the overflow prevention structure is connected to the bracket at the edge of the outer frame and extends toward the second surface of the outer frame to form a first step surface, the first The first differential surface maintains a first overflow depth with the second surface of the outer frame, and the first differential surface forms a coplanar abutment with the second surface of the bracket. The microfluidic control device of claim 1, wherein the overflow prevention structure is connected to the bracket at the edge of the outer frame and extends toward the second surface of the outer frame to form a second step surface. The second differential surface maintains a second overflow prevention depth with the second surface of the outer frame, the second differential surface maintains a third overflow prevention depth with the second surface of the bracket, and the second overflow prevention depth is greater than the first Three anti-overflow depth. The microfluidic control device of claim 1, wherein the overflow prevention structure is configured to connect the bracket to the edge of the outer frame and extend an anti-overflow recess and an overflow prevention toward the second surface of the outer frame. a convex portion, the overflow preventing concave portion abuts the outer frame, and the overflow preventing convex portion abuts the overflow preventing concave portion, wherein the overflow preventing concave portion has a third step surface and a fourth overflow prevention depth of the second surface of the outer frame And a top surface of the anti-overflow protrusion is coplanar with the second surface of the outer frame, and maintains a fifth overflow depth with the bracket. The microfluidic control device of claim 1, wherein the overflow prevention structure is connected to the bracket at an edge of the outer frame and extends in a ring shape toward the second surface of the outer frame to form a fourth differential surface. The fourth differential surface maintains a sixth overflow prevention depth with the second surface of the outer frame, and the fourth differential surface forms a coplanar abutment with the second surface of the bracket. A piezoelectric actuator comprising: a suspension plate having a first surface and a corresponding second surface, wherein the second surface has a convex portion; and an outer frame disposed around the outer side of the suspension plate And having a first surface and a corresponding second surface, the first surface of the suspension plate being coplanar with the first surface of the outer frame; at least one bracket connected to the suspension plate and the outer frame And having a first surface and a corresponding second surface, the first surface of the bracket being coplanar with the first surface of the outer frame; at least one overflow preventing structure formed on the outer frame Between the two surfaces and the second surface of the bracket to maintain a height difference between the outer frame and the bracket; and a piezoelectric ceramic plate attached to the first surface of the suspension plate. The piezoelectric actuator of claim 6, wherein the overflow preventing structure is connected to the bracket at the edge of the outer frame and extends toward the second surface to form a first step surface, the first step surface Maintaining a first overflow depth with the second surface of the frame, and the first step surface forms a coplanar abutment with the second surface of the bracket. The piezoelectric actuator of claim 6, wherein the overflow preventing structure is connected to the bracket at the edge of the outer frame and extends toward the second surface of the outer frame to form a second step surface. The second differential surface and the second surface of the outer frame maintain a second overflow prevention depth, the second differential surface maintains a third overflow prevention depth with the second surface of the bracket, and the second overflow prevention depth is greater than The third overflow prevention depth. The piezoelectric actuator of claim 6, wherein the overflow prevention structure is configured to connect the bracket to the edge of the outer frame and extend an anti-overflow recess and an anti-overflow toward the second surface of the outer frame. The overflow preventing portion abuts the outer frame, and the overflow preventing convex portion abuts the overflow preventing concave portion, wherein the overflow preventing concave portion has a third step surface and a fourth overflow prevention surface of the second surface of the outer frame The depth, and the top surface of the overflow relief is coplanar with the second surface of the outer frame and maintains a fifth overflow depth with the bracket. The piezoelectric actuator according to claim 6, wherein the overflow preventing structure is connected to the bracket at the edge of the outer frame and extends in a ring shape toward the second surface of the outer frame to form a fourth step surface. The fourth differential surface maintains a sixth overflow depth with the second surface of the outer frame, and the fourth differential surface forms a coplanar abutment with the second surface of the bracket.