Patent Publication Number: US-10788028-B2

Title: Fluid control device with alignment features on the flexible plate and communication plate

Description:
FIELD OF THE INVENTION 
     The present invention relates to a fluid control device, and more particularly to a fluid control device with a deformable base. 
     BACKGROUND OF THE INVENTION 
     With the advancement of science and technology, fluid control devices are widely used in many sectors such as pharmaceutical industries, computer techniques, printing industries or energy industries. Moreover, the fluid control devices are developed toward elaboration and miniaturization. The fluid control devices are important components that are used in for example micro pumps, micro atomizers, printheads or industrial printers for transporting fluid. Therefore, it is important to provide an improved structure of the fluid control device. 
       FIG. 1A  is a schematic cross-sectional view illustrating a portion of a conventional fluid control device.  FIG. 1B  is a schematic cross-sectional view illustrating an assembling shift condition of the conventional fluid control device. The main components of the conventional fluid control device  100  comprise a substrate  101  and a piezoelectric actuator  102 . The substrate  101  and the piezoelectric actuator  102  are stacked on each other, assembled by any well known assembling means such as adhesive, and separated from each other by a gap  103 . In an ideal situation, the gap  103  is maintained at a specified depth. More particularly, the gap  103  specifies the interval between an alignment central portion of the substrate  101  and a neighborhood of a central aperture of the piezoelectric actuator  102 . In response to an applied voltage, the piezoelectric actuator  102  is subjected to deformation and a fluid is driven to flow through various chambers of the fluid control device  100 . In such way, the purpose of transporting the fluid is achieved. 
     The piezoelectric actuator  102  and the substrate  101  of the fluid control device  100  are both flat-plate structures with certain rigidities. Thus, it is difficult to precisely align these two flat-plate structures to make the specified gap  103  and maintain it. If the gap  103  was not maintained in the specified depth, an assembling error would occur. Further explanation is exemplified as below. Referring to  FIG. 1B , the piezoelectric actuator  102  is inclined at an angle θ by one side as a pivot. Most regions of the piezoelectric actuator  102  deviate from the expected horizontal position by an offset, and the offset of each point of the regions is correlated positively with its parallel distance to the pivot. In other words, slight deflection can cause a certain amount of deviation. As shown in  FIG. 1B , one indicated region of the piezoelectric actuator  102  deviates from the standard by d while another indicated region can deviate by d′. As the fluid control device is developed toward miniaturization, miniature components are adopted. Consequently, the difficulty of maintaining the specified depth of the gap  103  has increased. The failure of maintaining the depth of the gap  103  causes several problems. For example, if the gap  103  is increased by d′, the fluid transportation efficiency is reduced. On the other hand, if the gap  103  is decreased by d′, the distance of the gap  103  is shortened and is unable to prevent the piezoelectric actuator  102  from readily being contacted or interfered by other components during operation. Under this circumstance, noise is generated, and the performance of the fluid control device is reduced. 
     Since the piezoelectric actuator  102  and the substrate  101  of the fluid control device  100  are flat-plate structures with certain rigidities, it is difficult to precisely align these two flat-plate structures. Especially when the sizes of the components are gradually decreased, the difficulty of precisely aligning the miniature components is largely enhanced. Under this circumstance, the performance of transferring the fluid is deteriorated, and the unpleasant noise is generated. 
     Therefore, there is a need of providing an improved fluid control device in order to eliminate the above drawbacks. 
     SUMMARY OF THE INVENTION 
     The present invention provides a fluid control device. The fluid control device has a miniature substrate and a miniature piezoelectric actuator. Since the substrate is deformable, a specified depth between a flexible plate of the substrate and a vibration plate of the piezoelectric actuator is maintained. Consequently, the assembling error is reduced, the efficiency of transferring the fluid is enhanced, and the noise is reduced. That is, the fluid control device of the present invention is more user-friendly. 
     In accordance with an aspect of the present invention, there is provided a fluid control device. The fluid control device includes a piezoelectric actuator and a deformable substrate. The piezoelectric actuator includes a piezoelectric element and a vibration plate having a first surface and an opposing second surface. The piezoelectric element is attached on the first surface of the vibration plate. The piezoelectric element is subjected to deformation in response to an applied voltage. The vibration plate is subjected to a curvy vibration in response to the deformation of the piezoelectric element. A bulge is formed on the second surface of the vibration plate. The deformable substrate includes a flexible plate and a communication plate. The flexible plate is stacked on and coupled with the communication plate. The deformable substrate is subjected to synchronous deformation. Consequently, a synchronously-deformed structure is formed on the deformable substrate and defined by the flexible plate and the communication plate collaboratively. The deformable substrate is combined with and positioned on the vibration plate of the piezoelectric actuator. Consequently, a specified depth is defined between the flexible plate of the deformable substrate and the bulge of the vibration plate. The flexible plate includes a movable part corresponding to the bulge of the vibration plate. 
     The above contents of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic cross-sectional view illustrating a portion of a conventional fluid control device; 
         FIG. 1B  is a schematic cross-sectional view illustrating an assembling shift condition of the conventional fluid control device; 
         FIG. 2A  is a schematic exploded view illustrating a fluid control device according to an embodiment of the present invention and taken along a first viewpoint; 
         FIG. 2B  is a schematic perspective view illustrating the assembled structure of the fluid control device of  FIG. 2A ; 
         FIG. 3  is a schematic exploded view illustrating the fluid control device of  FIG. 2A  and taken along a second viewpoint; 
         FIG. 4A  is a schematic cross-sectional view of the fluid control device of  FIG. 2A ; 
         FIGS. 4B and 4C  are schematic cross-sectional views illustrating the actions of the fluid control device of  FIG. 2A ; 
         FIG. 5A  is a schematic cross-sectional view illustrating a first example of the synchronously-deformed structure of the deformable substrate of the fluid control device; 
         FIG. 5B  is a schematic cross-sectional view illustrating a second example of the synchronously-deformed structure of the deformable substrate of the fluid control device; 
         FIG. 5C  is a schematic cross-sectional view illustrating a third example of the synchronously-deformed structure of the deformable substrate of the fluid control device; 
         FIG. 5D  is a schematic cross-sectional view illustrating a fourth example of the synchronously-deformed structure of the deformable substrate of the fluid control device; 
         FIG. 6A  is a schematic cross-sectional view illustrating a fifth example of the synchronously-deformed structure of the deformable substrate of the fluid control device; 
         FIG. 6B  is a schematic cross-sectional view illustrating a sixth example of the synchronously-deformed structure of the deformable substrate of the fluid control device; 
         FIG. 6C  is a schematic cross-sectional view illustrating a seventh example of the synchronously-deformed structure of the deformable substrate of the fluid control device; 
         FIG. 6D  is a schematic cross-sectional view illustrating an eighth example of the synchronously-deformed structure of the deformable substrate of the fluid control device; 
         FIG. 7A  is a schematic cross-sectional view illustrating a ninth example of the synchronously-deformed structure of the deformable substrate of the fluid control device; 
         FIG. 7B  is a schematic cross-sectional view illustrating a tenth example of the synchronously-deformed structure of the deformable substrate of the fluid control device; 
         FIG. 7C  is a schematic cross-sectional view illustrating an eleventh example of the synchronously-deformed structure of the deformable substrate of the fluid control device; 
         FIG. 7D  is a schematic cross-sectional view illustrating a twelfth example of the synchronously-deformed structure of the deformable substrate of the fluid control device; and 
         FIG. 8  is a schematic cross-sectional view illustrating a thirteenth example of the synchronously-deformed structure of the deformable substrate of the fluid control device. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed. 
     The present invention provides a fluid control device. The fluid control device can be used in many sectors such as pharmaceutical industries, energy industries computer techniques or printing industries for transporting fluids. 
     Please refer to  FIGS. 2A, 2B, 3 and 4A .  FIG. 2A  is a schematic exploded view illustrating a fluid control device according to an embodiment of the present invention and taken along a first viewpoint.  FIG. 2B  is a schematic perspective view illustrating the assembled structure of the fluid control device of  FIG. 2A .  FIG. 3  is a schematic exploded view illustrating the fluid control device of  FIG. 2A  and taken along a second viewpoint.  FIG. 4A  is a schematic cross-sectional view of the fluid control device of  FIG. 2A . 
     As shown in  FIGS. 2A and 3 , the fluid control device  2  comprises a deformable substrate  20 , a piezoelectric actuator  23 , a first insulating plate  241 , a conducting plate  25 , a second insulating plate  242  and a housing  26 . The deformable substrate  20  comprises a communication plate  21  and a flexible plate  22 . The piezoelectric actuator  23  is aligned with the flexible plate  22 . The piezoelectric actuator  23  comprises a vibration plate  230  and a piezoelectric element  233 . Moreover, the deformable substrate  20 , the piezoelectric actuator  23 , the first insulating plate  241 , the conducting plate  25  and the second insulating plate  242  are sequentially stacked on each other, and received within the housing  26 . 
     Please refer to  FIGS. 2A, 2B, 3 and 4A  again. The communication plate  21  has an inner surface  21   b  and an outer surface  21   a . The inner surface  21   b  and the outer surface  21   a  are opposed to each other. As shown in  FIG. 3 , at least one inlet  210  is formed on the outer surface  21   a  of the communication plate  21 . In this embodiment, four inlets  210  are formed on the outer surface  21   a  of the communication plate  21 . It is noted that the number of the inlets  210  may be varied according to the practical requirements. The inlets  210  run through the inner surface  21   b  and the outer surface  21   a  of the communication plate  21 . In response to the action of the atmospheric pressure, an external fluid can be introduced into the fluid control device  2  through the at least one inlet  210 . As shown in  FIG. 2A , at least one convergence channel  211  is formed on the inner surface  21   b  of the communication plate  21 . The at least one convergence channel  211  is in communication with the at least one inlet  210  running through the outer surface  21   a  of the communication plate  21 . Moreover, a central cavity  212  is formed on the inner surface  21   b  of the communication plate  21 . The central cavity  212  is in communication with the at least one convergence channel  211 . After the fluid is introduced into the fluid control device  2  via the at least one inlet  210 , the fluid is guided through the at least one convergence channel  211  to the central cavity  212 . Consequently, the fluid can be further transferred downwardly. In this embodiment, the at least one inlet  210 , the at least one convergence channel  211  and the central cavity  212  of the communication plate  21  are integrally formed. The central cavity  212  forms a convergence chamber for temporarily storing the fluid. Preferably but not restricted, the communication plate  21  is made of stainless steel, and the flexible plate  22  is made of a flexible material. The flexible plate  22  comprises a central aperture  220  corresponding to the central cavity  212  of the communication plate  21 . Consequently, the fluid can be transferred downwardly through the central aperture  220 . Preferably but not exclusively, the flexible plate  22  is made of copper. The flexible plate  22  is coupled with the communication plate  21  and comprises a movable part  22   a  and a fixed part  22   b . The fixed part  22   b  is fixed on the communication plate  21 , whereas the movable part  22   a  is aligned with the central cavity  212 . The central aperture  220  is formed in the movable part  22   a.    
     Please refer to  FIGS. 2A, 2B and 3  again. The piezoelectric actuator  23  comprises a piezoelectric element  233 , a vibration plate  230 , an outer frame  231  and at least one bracket  232 . In this embodiment, the vibration plate  230  has a square flexible film structure. The vibration plate  230  has a first surface  230   b  and an opposing second surface  230   a . The piezoelectric element  233  has a square shape. The side length of the piezoelectric element  233  is not larger than the side length of the vibration plate  230 . Moreover, the piezoelectric element  233  is attached on the first surface  230   b  of the vibration plate  230 . By applying a voltage to the piezoelectric element  233 , the piezoelectric element  233  is subjected to deformation to result in curvy vibration of the vibration plate  230 . Moreover, a bulge  230   c  is formed on the second surface  230   a  of the vibration plate  230 . For example, the bulge  230   c  is a circular convex structure. The vibration plate  230  is enclosed by the outer frame  231 . The profile of the outer frame  231  substantially matches the profile of the vibration plate  230 . That is, the outer frame  231  is a square hollow frame. Moreover, the at least one bracket  232  is connected between the vibration plate  230  and the outer frame  231  for elastically supporting the vibration plate  230 . 
     As shown in  FIGS. 2A, 2B  and  FIG. 3 , the housing  26  comprises at least one outlet  261 . The housing  26  comprises a bottom plate and a sidewall structure  260 . The sidewall structure  260  protrudes from the peripheral of the bottom plate. An accommodation space  26   a  is defined by the bottom plate and the sidewall structure  260  collaboratively. The piezoelectric actuator  23  is disposed within the accommodation space  26   a . After the fluid control device  2  is assembled, the assembled structure of the fluid control device  2  is shown in  FIGS. 2B and 4A . The piezoelectric actuator  23  and the deformable substrate  20  are covered by the housing  26 . In addition, a temporary storage chamber A is formed between the housing  26  and the piezoelectric actuator  23  for temporarily storing the fluid. The outlet  261  is in communication with the temporary storage chamber A. Consequently, the fluid can be discharged from the housing  26  through the outlet  261 . 
       FIG. 4A  is a schematic cross-sectional view of the fluid control device of  FIG. 2A .  FIGS. 4B and 4C  are schematic cross-sectional views illustrating the actions of the fluid control device of  FIG. 2A . For succinctness, the first insulating plate  241 , the conducting plate  25  and the second insulating plate  242  are not shown in  FIGS. 4A, 4B and 4C . Moreover, the deformable substrate  20  shown in  FIGS. 4A, 4B and 4C  has not subjected to a synchronous deformation yet. These drawings are employed to indicate the relationship and interactions between the communication plate  21  and the flexible plate  22  of the deformable substrate  20  and the piezoelectric actuator  23 . 
     Please refer to  FIG. 4A . After the communication plate  21 , the flexible plate  22  and the piezoelectric actuator  23  are assembled, a convergence chamber is defined by partial flexible plate  22  including the central aperture  220  and the central cavity  212  of the communication plate  21  collaboratively. There is a gap h between the flexible plate  22  and the outer frame  231  of the piezoelectric actuator  23 . Preferably but not exclusively, a medium (e.g., a conductive adhesive) is filled in the gap h. Consequently, the flexible plate  22  and the outer frame  231  of the piezoelectric actuator  23  are connected with each other through the medium and form a compressible chamber B therebetween. At the same time, a specified depth δ is defined between the flexible plate  22  and the bulge  230   c  of the piezoelectric actuator  23 . When the vibration plate  230  of the piezoelectric actuator  23  vibrates, the fluid in the compressible chamber B is compressed and the specified depth δ reduces. Consequently, the pressure and the flow rate of the fluid are increased. In addition, the specified depth δ is a proper distance that is sufficient to prevent the contact interference between the flexible plate  22  and the piezoelectric actuator  23  and therefore reduce the noise generation. Moreover, the convergence chamber defined by the flexible plate  22  and the central cavity  212  of the communication plate  21  is in communication with the compressible chamber B. 
     When the fluid control device  2  is enabled, the piezoelectric actuator  23  is actuated in response to an applied voltage. Consequently, the piezoelectric actuator  23  vibrates along a vertical direction in a reciprocating manner. Please refer to  FIG. 4B . When the piezoelectric actuator  23  vibrates upwardly, since the flexible plate  22  is light and thin, the flexible plate  22  vibrates simultaneously because of the resonance of the piezoelectric actuator  23 . More especially, the movable part  22   a  of the flexible plate  22  is subjected to a curvy deformation. The central aperture  220  is located near or located at the center of the flexible plate  22 . Since the piezoelectric actuator  23  vibrates upwardly, the movable part  22   a  of the flexible plate  22  correspondingly moves upwardly, making an external fluid introduced by the at least one inlet  210 , through the at least one convergence channel  211 , into the convergence chamber. After that, the fluid is transferred upwardly to the compressible chamber B through the central aperture  220  of the flexible plate  22 . As the flexible plate  22  is subjected to deformation, the volume of the compressible chamber B is compressed so as to enhance the kinetic energy of the fluid therein and make it flow to the bilateral sides, then transferred upwardly through the vacant space between the vibration plate  230  and the bracket  232 . 
     Please refer to  FIG. 4C . As the piezoelectric actuator  23  vibrates downwardly, the movable part  22   a  of the flexible plate  22  correspondingly moves downwardly and subjected to the downward curvy deformation because of the resonance of the piezoelectric actuator  23 . Meanwhile, less fluid is converged to the convergence chamber in the central cavity  212  of the communication plate  21 . Since the piezoelectric actuator  23  vibrates downwardly, the volume of the compressible chamber B increases. 
     The step of  FIG. 4B  and the step of  FIG. 4C  are repeatedly done so as to expand or compress the compressible chamber B, thus enlarging the amount of inhalation or discharge of the fluid. 
     Moreover, the deformable substrate  20  comprises the communication plate  21  and the flexible plate  22 . The communication plate  21  and the flexible plate  22  are stacked on each other and subjected to synchronous deformation so that forming a synchronously-deformed structure, which is defined by the communication plate  21  and the flexible plate  22  collaboratively and fixed. Specifically, the synchronously-deformed structure is defined by a synchronously-deformed region of the communication plate  21  and a synchronously-deformed region of the flexible plate  22  collaboratively. When one of the communication plate  21  and the flexible plate  22  is subjected to deformation, another is also subjected to deformation synchronously. Moreover, the deformation shape of the communication plate  21  and the deformation shape of the flexible plate  22  are identical. As a result, after the corresponding surfaces of the communication plate  21  and the flexible plate  22  are contacted with and positioned on each other, there is merely little interval or parallel offset happened therebetween. Preferably but not exclusively, the communication plate  21  and the flexible plate  22  are contacted with each other through a binder. 
     As mentioned in  FIG. 1B , the piezoelectric actuator  102  and the substrate  101  of the conventional fluid control device  100  are flat-plate structures with certain rigidities. Consequently, it is difficult to precisely align these two flat-plate structures and make them separated by the specified gap  103  (i.e., maintain the specified depth). That is, the misalignment of the piezoelectric actuator  102  and the substrate  101  readily occurs. In accordance with the present invention, the synchronously-deformed structure of the deformable substrate  20  is defined in response to the synchronous deformation of the communication plate  21  and the flexible plate  22 . Moreover, the function of the synchronously-deformed structure is similar to the function of the substrate  101  of the conventional technology. More especially, the synchronously-deformed structure defined by the communication plate  21  and the flexible plate  22  has various implementation examples. In these implementation examples, a compressible chamber B corresponding to the specified depth δ (i.e., a specified gap between the synchronously-deformed structure and the vibration plate  230  of the piezoelectric actuator  23 ) is maintained according to the practical requirements. Consequently, the fluid control device  2  is developed toward miniaturization, and the miniature components are adopted. Due to the synchronously-deformed structure, it is easy to maintain the specified gap between the deformable substrate and the vibration plate. As previously described, the conventional technology has to precisely align two large-area flat-plate structures. In accordance with the feature of the present invention, the area to be aligned reduces because the deformable substrate  20  has the synchronously-deformed structure and is not a flat plate. The shape of the synchronously-deformed structure is not restricted. For example, the synchronously-deformed structure has a curvy shape, a conical shape, a curvy-surface profile or an irregular shape. Compared with aligning two large areas of the two flat plates, aligning one small area of a non-flat-plate with a flat plate is much easier and can reduce assembling errors. Under this circumstance, the performance of transferring the fluid is enhanced and the noise is reduced. 
     In some embodiments, the synchronously-deformed structure is defined by the entire communication plate  21  and the entire flexible plate  22  collaboratively. In these cases, the synchronously-deformed region of the flexible plate  22  includes the movable part  22   a  and the region beyond the movable part  22   a . In addition, the synchronously-deformed structure of the deformable substrate  20  includes but not limited to a curvy structure, a conical structure and a convex structure. Some examples of the synchronously-deformed structure of the deformable substrate of the fluid control device will be described as follows. 
     Please refer to  FIGS. 5A and 5C .  FIG. 5A  is a schematic cross-sectional view illustrating a first example of the synchronously-deformed structure of the deformable substrate of the fluid control device.  FIG. 5C  is a schematic cross-sectional view illustrating a third example of the synchronously-deformed structure of the deformable substrate of the fluid control device. In the examples of  FIGS. 5A and 5C , the synchronously-deformed structure is defined by the entire communication plate  21  and the entire flexible plate  22  collaboratively. That is, the synchronously-deformed region of the flexible plate  22  includes the movable part  22   a  and the region beyond the movable part  22   a . The deformation direction of the example of  FIG. 5A  and the deformation direction of the example of  FIG. 5C  are opposite. As shown in  FIG. 5A , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is bent in the direction toward the bulge  230   c  of the vibration plate  230 . Moreover, the movable part  22   a  and the region beyond the movable part  22   a  of the flexible plate  22  are also bent in the direction toward the bulge  230   c  of the vibration plate  230 . The bent communication plate  21  and the bent flexible plate  22  define the synchronously-deformed structure of the deformable substrate  20 ′. As shown in  FIG. 5C , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is bent in the direction away from the bulge  230   c  of the vibration plate  230 . Simultaneously, the movable part  22   a  and the region beyond the movable part  22   a  of the flexible plate  22  are also bent in the direction away from the bulge  230   c  of the vibration plate  230 . The bent communication plate  21  and the bent flexible plate  22  define the synchronously-deformed structure of the deformable substrate  20 ′. Under this circumstance, the specified depth δ is maintained between the flexible plate  22  and the bulge  230   c  of the vibration plate  230 , more particularly between the movable part  22   a  and the bulge  230   c  of the vibration plate  230 . Consequently, the fluid control device  2  with the synchronously-deformed structure is produced. 
     Please refer to  FIGS. 6A and 6C .  FIG. 6A  is a schematic cross-sectional view illustrating a fifth example of the synchronously-deformed structure of the deformable substrate of the fluid control device.  FIG. 6C  is a schematic cross-sectional view illustrating a seventh example of the synchronously-deformed structure of the deformable substrate of the fluid control device. In the examples of  FIGS. 6A and 6C , the synchronously-deformed structure is a conical synchronously-deformed structure  201  that is defined by the entire communication plate  21  and the entire flexible plate  22  collaboratively. That is, the synchronously-deformed region of the flexible plate  22  includes the region of the movable part  22   a  and the region beyond the movable part  22   a . The deformation direction of the example of  FIG. 6A  and the deformation direction of the example of  FIG. 6C  are opposite. As shown in  FIG. 6A , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is bent in the direction toward the bulge  230   c  of the vibration plate  230 . Moreover, the region of the movable part  22   a  and the region beyond the movable part  22   a  of the flexible plate  22  are also bent in the direction toward the bulge  230   c  of the vibration plate  230 . As a consequence, the conical synchronously-deformed structure of the deformable substrate  20 ′ is defined. As shown in  FIG. 6C , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is bent in the direction away from the bulge  230   c  of the vibration plate  230 . Moreover, the region of the movable part  22   a  and the region beyond the movable part  22   a  of the flexible plate  22  are also bent away from the bulge  230   c  of the vibration plate  230 . As a consequence, the conical synchronously-deformed structure of the deformable substrate  20 ′ is defined. Under this circumstance, the specified depth .delta. is maintained between the movable part  22   a  of the flexible plate  22  and the bulge  230   c  of the vibration plate  230 . Consequently, the fluid control device  2  with the conical synchronously-deformed structure is produced. 
     Please refer to  FIGS. 7A and 7C .  FIG. 7A  is a schematic cross-sectional view illustrating a ninth example of the synchronously-deformed structure of the deformable substrate of the fluid control device.  FIG. 7C  is a schematic cross-sectional view illustrating an eleventh example of the synchronously-deformed structure of the deformable substrate of the fluid control device. In the examples of  FIGS. 7A and 7C , the synchronously-deformed structure is a convex synchronously-deformed structure that is defined by the entire communication plate  21  and the entire flexible plate  22  collaboratively. That is, the synchronously-deformed region of the flexible plate  22  includes the movable part  22   a  and the region beyond the movable part  22   a . The deformation direction of the example of  FIG. 7A  and the deformation direction of the example of  FIG. 7C  are opposite. As shown in  FIG. 7A , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is bent in the direction toward the bulge  230   c  of the vibration plate  230 . Moreover, the movable part  22   a  and the region beyond the movable part  22   a  of the flexible plate  22  are also bent in the direction toward the bulge  230   c  of the vibration plate  230 . As a consequence, the convex synchronously-deformed structure of the deformable substrate  20 ′ is defined. As shown in  FIG. 7C , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is bent in the direction away from the bulge  230   c  of the vibration plate  230 . Moreover, the movable part  22   a  and the region beyond the movable part  22   a  of the flexible plate  22  are also bent in the direction away from the bulge  230   c  of the vibration plate  230 . As a consequence, the convex synchronously-deformed structure of the deformable substrate  20 ′ is defined. Under this circumstance, the specified depth δ is maintained between the movable part  22   a  of the flexible plate  22  and the bulge  230   c  of the vibration plate  230 . Consequently, the fluid control device  2  with the convex synchronously-deformed structure is produced. 
     Alternatively, the synchronously-deformed structure is defined by a part of the communication plate  21  and a part of the flexible plate  22  collaboratively. That is, the synchronously-deformed region of the flexible plate  22  includes the region of the movable part  22   a  only, and the scale of the synchronously-deformed region of the communication plate  21  corresponds to the synchronously-deformed region of the flexible plate  22 . In addition, the synchronously-deformed structure of the deformable substrate  20 ′ includes but not limited to a curvy structure, a conical structure and a convex structure. 
     Please refer to  FIGS. 5B and 5D .  FIG. 5B  is a schematic cross-sectional view illustrating a second example of the synchronously-deformed structure of the deformable substrate of the fluid control device.  FIG. 5D  is a schematic cross-sectional view illustrating a fourth example of the synchronously-deformed structure of the deformable substrate of the fluid control device. In the examples of  FIGS. 5B and 5D , the synchronously-deformed structure is defined by a part of the communication plate  21  and a part of the flexible plate  22  collaboratively. The synchronously-deformed region of the flexible plate  22  includes the region of the movable part  22   a  only, and the synchronously-deformed region of the communication plate  21  corresponds to the synchronously-deformed region of the flexible plate  22 . That is, the synchronously-deformed structures of  FIGS. 5B and 5D  are produced by partially deforming the deformable substrate  20 ′. The deformation direction of the example of  FIG. 5B  and the deformation direction of the example of  FIG. 5D  are opposite. As shown in  FIG. 5B , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is partially bent in the direction toward the bulge  230   c  of the vibration plate  230 . Moreover, the region of the movable part  22   a  of the flexible plate  22  is also bent in the direction toward the bulge  230   c  of the vibration plate  230 . As a consequence, the partially-bent synchronously-deformed structure of the deformable substrate  20 ′ is defined. As shown in  FIG. 5D , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is partially bent in the direction away from the bulge  230   c  of the vibration plate  230 . Moreover, the region of the movable part  22   a  of the flexible plate  22  is also bent in the direction away from the bulge  230   c  of the vibration plate  230 . As a consequence, the partially-bent synchronously-deformed structure of the deformable substrate  20 ′ is defined. Under this circumstance, the specified depth δ is maintained between the movable part  22   a  of the flexible plate  22  and the bulge  230   c  of the vibration plate  230 . Consequently, the fluid control device  2  with the partially-bent synchronously-deformed structure is produced. 
     Please refer to  FIGS. 6B and 6D .  FIG. 6B  is a schematic cross-sectional view illustrating a sixth example of the synchronously-deformed structure of the deformable substrate of the fluid control device.  FIG. 6D  is a schematic cross-sectional view illustrating an eighth example of the synchronously-deformed structure of the deformable substrate of the fluid control device. In the examples of  FIGS. 6B and 6D , the synchronously-deformed structure is defined by a part of the communication plate  21  and a part of the flexible plate  22  collaboratively. The synchronously-deformed region of the flexible plate  22  includes the region of the movable part  22   a  only, and the synchronously-deformed region of the communication plate  21  corresponds to the synchronously-deformed region of the flexible plate  22 . That is, the synchronously-deformed structures of  FIGS. 6B and 6D  are produced by partially deforming the deformable substrates  20 ′ to conical synchronously-deformed structures  201 . The deformation direction of the example of  FIG. 6B  and the deformation direction of the example of  FIG. 6D  are opposite. As shown in  FIG. 6B , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is partially bent in the direction toward the bulge  230   c  of the vibration plate  230 . Moreover, the region of the movable part  22   a  of the flexible plate  22  is also partially bent in the direction toward the bulge  230   c  of the vibration plate  230 . As a consequence, the conical synchronously-deformed structure of the deformable substrate  20 ′ is defined. As shown in  FIG. 6D , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is partially bent in the direction away from the bulge  230   c  of the vibration plate  230 . Moreover, the region of the movable part  22   a  of the flexible plate  22  is also partially bent in the direction away from the bulge  230   c  of the vibration plate  230 . As a consequence, the conical synchronously-deformed structure of the deformable substrate  20 ′ is defined. Under this circumstance, the specified depth .delta. is maintained between the movable part  22   a  of the flexible plate  22  and the bulge  230   c  of the vibration plate  230 . Consequently, the fluid control device  2  with the conical synchronously-deformed structure is produced. 
     Please refer to  FIGS. 7B and 7D .  FIG. 7B  is a schematic cross-sectional view illustrating a tenth example of the synchronously-deformed structure of the deformable substrate of the fluid control device.  FIG. 7D  is a schematic cross-sectional view illustrating a twelfth example of the synchronously-deformed structure of the deformable substrate of the fluid control device. In the examples of  FIGS. 7B and 7D , the synchronously-deformed structure is defined by a part of the communication plate  21  and a part of the flexible plate  22  collaboratively. The synchronously-deformed region of the flexible plate  22  includes the region of the movable part  22   a  only, and the synchronously-deformed region of the communication plate  21  corresponds to the synchronously-deformed region of the flexible plate  22 . That is, the synchronously-deformed structures of  FIGS. 7B and 7D  are produced by partially deforming the deformable substrates  20 ′ to the convex synchronously-deformed structures. The deformation direction of the example of  FIG. 7B  and the deformation direction of the example of  FIG. 7D  are opposite. As shown in  FIG. 7B , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is partially bent in the direction toward the bulge  230   c  of the vibration plate  230 . Moreover, the region of the movable part  22   a  of the flexible plate  22  is also partially bent in the direction toward the bulge  230   c  of the vibration plate  230 . As a consequence, the convex synchronously-deformed structure of the deformable substrate  20 ′ is defined. As shown in  FIG. 7D , the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′ is partially bent in the direction away from the bulge  230   c  of the vibration plate  230 . Moreover, the region of the movable part  22   a  of the flexible plate  22  is also bent in the direction away from the bulge  230   c  of the vibration plate  230 . As a consequence, the convex synchronously-deformed structure of the deformable substrate  20 ′ is defined. Under this circumstance, the specified depth δ is maintained between the movable part  22   a  of the flexible plate  22  and the bulge  230   c  of the vibration plate  230 . Consequently, the fluid control device  2  with the convex synchronously-deformed structure is produced. 
       FIG. 8  is a schematic cross-sectional view illustrating an example of the synchronously-deformed structure of the deformable substrate of the fluid control device. The synchronously-deformed structure also can be a curvy-surface synchronously-deformed structure, which is composed of plural curvy surfaces with different or identical curvatures. As shown in  FIG. 8 , the curvy-surface synchronously-deformed structure comprises plural curvy surfaces with different curvatures. A set of the plural curvy surfaces are formed on the outer surface  21   a  of the communication plate  21  of the deformable substrate  20 ′, while another set of curvy surfaces corresponding to the former set are formed on the flexible plate  22 . Under this circumstance, the specified depth δ is maintained between the curvy-surface synchronously-deformed structure and the bulge  230   c  of the vibration plate  230 . Consequently, the fluid control device  2  with the curvy-surface synchronously-deformed structure is produced. 
     In some other embodiments, the synchronously-deformed structure is an irregular synchronously-deformed structure, which is produced by making two sets of identical irregular surfaces on the communication plate  21  and the flexible plate  22  of the deformable substrate  20 ′. Consequently, the irregular synchronously-deformed structure is defined by the communication plate  21  and the flexible plate  22 . Under this circumstance, the specified depth δ is still maintained between the irregular synchronously-deformed structure and the bulge  230   c  of the vibration plate  230 . 
     As mentioned above, the synchronously-deformed structure of the deformable substrate has a curvy structure, a conical structure, a convex structure, a curvy-surface structure or an irregular structure. Under this circumstance, the specified depth δ is maintained between the movable part  22   a  of the deformable substrate  20  and the bulge  230   c  of the vibration plate  230 . Due to the specified depth δ, the gap h would not be too large or too small that causing the assembling errors. Moreover, the specified depth δ is sufficient to reduce the contact interference between the flexible plate  22  and the bulge  230   c  of the piezoelectric actuator  23 . Consequently, the efficiency of transferring the fluid is enhanced, and the noise is reduced. 
     From the above descriptions, the present invention provides a fluid control device. The synchronously-deformed structure is formed on and defined by the communication plate and the flexible plate of the deformable substrate. During operation, the synchronously-deformed structure is moved in the direction toward or away from the piezoelectric actuator. Consequently, the specified depth between the flexible plate and the bulge of the vibration plate is maintained. The specified depth is sufficient to reduce the contact interference between the flexible plate and the bulge of the piezoelectric actuator. Consequently, the efficiency of transferring the fluid is enhanced, and the noise is reduced. Since the specified depth is advantageous for increasing the efficiency of transferring the fluid and reducing the noise, the performance of the product is increased and the quality of the fluid control device is significantly improved. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.