Fluid control device

Abstract

A fluid control device of the present application includes an actuator, and a ring-shaped frame that fixes at least a portion of the outer circumference of the actuator. The actuator includes a piezoelectric body having a first main surface and a second main surface, and a vibrating plate connected to the first main surface of the piezoelectric body. The frame is disposed on the second main surface. The outer diameter of the vibrating plate and the outer diameter of the piezoelectric body are larger than the inner diameter of the frame, and the outer diameter of the vibrating plate or the outer diameter of the frame is larger than the outer diameter of the piezoelectric body.

Description

Technical Field

[0001] This invention relates to a fluid control device equipped with an actuator. Background Technology

[0002] Patent Document 1 discloses an actuator in which a plate-shaped piezoelectric element is attached to a plate-shaped vibrating plate. The actuator is equipped with a housing to cover the side of the vibrating plate. As a result, obstacles such as falling or being transported will not come into contact with the side of the piezoelectric element in the actuator of Patent Document 1.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2009-293507

[0004] In the structure of Patent Document 1, a housing is arranged on the outer side of the vibrating plate, thus increasing the outer diameter of the actuator. Summary of the Invention

[0005] The purpose of this invention is to provide a fluid control device that prevents obstacles from contacting the side of the piezoelectric element during falling or transportation and can reduce the outer diameter.

[0006] A fluid control device according to one embodiment of the present invention includes: an actuator; and an annular frame for fixing at least a portion of the outer periphery of the actuator. The actuator includes: a piezoelectric element having a first main surface and a second main surface; and a vibrating plate connected to the first main surface of the piezoelectric element. The frame is disposed on the second main surface. The outer diameter of the vibrating plate and the outer diameter of the piezoelectric element are larger than the inner diameter of the frame, and either the outer diameter of the vibrating plate or the outer diameter of the frame is larger than the outer diameter of the piezoelectric element.

[0007] According to the above structure, the outer diameter of the vibrating plate and the outer diameter of the piezoelectric element are larger than the inner diameter of the frame, thus allowing a pump chamber to be formed on the inner circumferential side of the frame. Therefore, the fluid control device in this embodiment can form a pump chamber without configuring a housing on the outermost circumferential side of the piezoelectric element and the vibrating plate. Furthermore, the outer diameters of the components connected to the first and second main surfaces of the piezoelectric element are larger than the outer diameter of the piezoelectric element, preventing obstacles from contacting the sides of the piezoelectric element during drops or transport.

[0008] According to the present invention, obstacles will not come into contact with the side of the piezoelectric element during falling or transportation, and the outer diameter can be reduced. Attached Figure Description

[0009] Figure 1 This is a cross-sectional view of the fluid control device 1.

[0010] Figure 2 This is a top view of the vibrating plate 11.

[0011] Figure 3 This is a top view of the piezoelectric element 10.

[0012] Figure 4 This is a top view of frame 12.

[0013] Figure 5 This is a top view of frame 17.

[0014] Figure 6 This is a cross-sectional view of the fluid control device 1 with the plate 83 mounted on the lower surface of the frame 17.

[0015] Figure 7 This is a cross-sectional view of the fluid control device 1A of Modified Example 1.

[0016] Figure 8 This is a bottom view of the piezoelectric element 10 in the fluid control device 1A.

[0017] Figure 9 This is a cross-sectional view of the vibrating plate 11 in the fluid control device 1A during bending vibration.

[0018] Figure 10 This is a cross-sectional view of the fluid control device 1B in variant example 2.

[0019] Figure 11 This is a cross-sectional view of the fluid control device 2 according to the second embodiment.

[0020] Figure 12 This is a cross-sectional view of the fluid control device 2 during bending vibration.

[0021] Figure 13 It is a graph showing the relationship between the distance of the main face (the main face away from the neutral face) of the piezoelectric material from the neutral face and the stress / amplitude (stress per amplitude).

[0022] Figure 14 This is a diagram showing the relationship between the distance from the main surface of the piezoelectric element to the neutral surface and the amplitude.

[0023] Figure 15 It is a graph showing the relationship between the amplitude and the radial stress at the center of the piezoelectric material.

[0024] Figure 16 This is a cross-sectional view showing the structure of a modified example 1 of a dual piezoelectric wafer.

[0025] Figure 17 This is a cross-sectional view showing the structure of a modified example 2 of a dual piezoelectric wafer.

[0026] Figure 18 This is a cross-sectional view showing the structure of Modified Example 3 of the dual piezoelectric wafer.

[0027] Figure 19 This is an exploded perspective view of the fluid control device in variant example 4.

[0028] Figure 20 This is a cross-sectional view showing the portion below the first vibrating plate 11A in the fluid control device 2D.

[0029] Figure 21 This is a cross-sectional view showing the portion below the first vibrating plate 11A in the fluid control device 2D.

[0030] Figure 22 This is a top view of the fluid control device in 2D.

[0031] Figure 23 It is a 2D stereoscopic view of a fluid control device.

[0032] Figure 24 This is a cross-sectional view showing the structure of other variations of the fluid control device.

[0033] Figure 25 yes Figure 24 A magnified view of a portion of the image. Detailed Implementation

[0034] The fluid control device of the first embodiment of the present invention will be described with reference to the accompanying drawings. Furthermore, in the figures shown in the following embodiments, the shapes of the various constituent elements are exaggerated, either partially or entirely, to facilitate understanding of the description.

[0035] Figure 1 This is a cross-sectional view of the fluid control device 1 according to the first embodiment of the present invention. The fluid control device 1 includes a piezoelectric element 10, a vibrating plate 11, a frame 12, a welding foot 13, a first electrode 14, a second electrode 15, and a frame 17.

[0036] Figure 2 This is a top view of the vibrating plate 11. Figure 3 This is a top view of the piezoelectric element 10. Figure 4 This is a top view of frame 12. Figure 5 This is a top view of frame 17. Figure 1 The sectional view is Figure 2 , Figure 3 , Figure 4 as well as Figure 5 The cross-sectional view of line A-A shown.

[0037] The piezoelectric element 10 is made of, for example, lead zirconate titanate ceramic. The piezoelectric element 10 is a thin, circular plate shape. A first electrode 14 is formed on the lower surface (first main surface) of the piezoelectric element 10, for example, by sputtering, and a second electrode 15 is formed on the upper surface (second main surface), for example, by sputtering. The piezoelectric element 10 deforms due to the driving voltage applied to the first electrode 14 and the second electrode 15. In this embodiment, viewed from above, the outer diameter of the piezoelectric element 10 is larger than the outer diameters of the first electrode 14 and the second electrode 15. This structure is not essential in this invention, but it prevents the electrodes (first electrode 14 and second electrode 15) from being exposed on the sides of the piezoelectric element 10. Therefore, during electrode formation, the electrodes do not extend into the sides of the piezoelectric element 10, suppressing short circuits.

[0038] A vibrating plate 11 is attached to the first electrode 14 using an adhesive. The adhesive contains multiple conductive fillers. These multiple conductive fillers are interconnected when the thickness of the adhesive is below a specified value. Therefore, the adhesive is conductive when the thickness is below the specified value and insulating when the thickness exceeds the specified value. The portion of the adhesive sandwiched between the vibrating plate 11 and the first electrode 14 has a thickness below the specified value and is conductive.

[0039] The vibrating plate 11 is circular. In this embodiment, the outer diameter of the piezoelectric element 10 is smaller than the outer diameter of the vibrating plate 11 when viewed from above.

[0040] A frame 17 is attached to the lower surface of the vibrating plate 11 using adhesive. Both the vibrating plate 11 and the frame 17 are made of conductive material. A drive circuit (not shown) is connected to the frame 17. Thus, a drive voltage is applied to the vibrating plate 11 via the frame 17.

[0041] A frame 12 is attached to the second electrode 15 using an adhesive. The frame 12 is made of a conductive material. The adhesive between the frame 12 and the second electrode 15 is less than a specified thickness and is conductive. A drive circuit (not shown) is connected to the frame 12. A drive voltage is thus applied via the frame 12.

[0042] Therefore, a driving voltage is applied to the first electrode 14 and the second electrode 15. The vibrating plate 11 is designed to vibrate at a predetermined resonant frequency. A driving voltage of a frequency corresponding to this resonant frequency is applied to the first electrode 14 and the second electrode 15.

[0043] For example, if a driving voltage is applied to the piezoelectric element 10 to contract in a direction parallel to the main surface, the upper surface of the vibrating plate 11 contracts, and the lower surface of the vibrating plate 11 elongates. Therefore, the lower surface of the vibrating plate 11 undergoes a convex bending deformation towards the lower surface direction. Alternatively, assuming the piezoelectric element 10 elongates in a direction parallel to the main surface, the lower surface of the vibrating plate 11 undergoes a concave bending deformation towards the upper surface direction. Thus, the vibrating plate 11 exhibits rotationally symmetrical (concentric circle) bending vibration from its center to its periphery. Therefore, the piezoelectric element 10 and the vibrating plate 11 function as actuators for a piezoelectric single-crystal oscillator. The frame 12 and frame 17 fix part or all of the outer periphery of the actuator. The frame 12 and frame 17 can be a ring-shaped arrangement of the entire outer periphery of the actuator in plan view, or a configuration where only a portion is arranged in plan view. Figure 1 In the structure shown, the first main surface of the actuator is the lower surface of the vibrating plate 11, and the second main surface corresponds to the upper surface of the piezoelectric body 10. If the vibrating plate 11 is disposed on the upper surface of the piezoelectric body 10, then the first main surface of the actuator is the lower surface of the piezoelectric body 10, and the second main surface corresponds to the upper surface of the vibrating plate 11.

[0044] The outer diameter of the vibrating plate 11 and the outer diameter of the piezoelectric element 10 are larger than the inner diameter of the frame 17. In addition, the outer diameter of the vibrating plate 11 and the outer diameter of the piezoelectric element 10 are larger than the inner diameter of the frame 12. As a result, the fluid control device 1 can form a pump chamber with the upper or lower surface of the actuator through the side of the inner circumference of the frame 12 or the frame 17. Figure 6 This is a cross-sectional view of the fluid control device 1 with the plate 83 mounted on the lower surface of the frame 17.

[0045] The plate 83, viewed from above, is a circular plate-shaped component. The plate 83 has a through hole at its center when viewed from above. The plate 83 is separated from the vibrating plate 11 by the frame 17. Figure 6 In this structure, a pump chamber is formed by the space enclosed by the inner circumferential side of the frame 17, the lower surface of the vibrating plate 11, and the upper surface of the plate 83. When the vibrating plate 11 vibrates, the plate 83 vibrates due to the pressure changes within the pump chamber accompanying the vibration of the vibrating plate 11. The vibration phase of the plate 83 is delayed compared to the vibration phase of the vibrating plate 11. Therefore, the thickness variation of the gap space between the plate 83 and the vibrating plate 11 substantially increases, further enhancing the pump's capacity.

[0046] In the fluid control device 1 of this embodiment as described above, the outer diameter of the vibrating plate 11 and the outer diameter of the piezoelectric element 10 are larger than the inner diameter of the frame 17, thus allowing the inner circumferential side of the frame 17 to form part of the housing of the fluid control device 1. Furthermore, in the fluid control device 1, the outer diameter of the vibrating plate 11 and the outer diameter of the piezoelectric element 10 are larger than the inner diameter of the frame 12, thus allowing the inner circumferential side of the frame 12 to form part of the housing of the fluid control device 1. Therefore, compared to the structure in Patent Document 1 (Japanese Patent Application Laid-Open No. 2009-293507) where the housing is located on the outer side of the vibrating plate, the overall outer diameter of the fluid control device 1 of this embodiment is smaller.

[0047] Furthermore, in the fluid control device 1 of this embodiment, the outer diameters of the components (vibrating plate 11 and frame 12) that are respectively connected to the first main surface and the second main surface of the piezoelectric body 10 are larger than the outer diameter of the piezoelectric body 10. Therefore, obstacles such as those in the fluid control device 1 of this embodiment will not come into contact with the side of the piezoelectric body when it is dropped or transported.

[0048] That is, the fluid control device 1 of this embodiment will not come into contact with the side of the piezoelectric element when it is dropped or transported, and the outer diameter can be reduced.

[0049] Furthermore, in the fluid control device 1 of this embodiment, solder feet 13 are formed between the main surface of the piezoelectric element 10 and the main surface of the vibrating plate 11, between the main surface of the piezoelectric element 10 and the side surface of the frame 12, and between the main surface of the vibrating plate 11 and the side surface of the frame 17. The solder feet 13 are formed by the exposure of the aforementioned adhesive. The solder feet 13 in each part have a predetermined thickness or more, and therefore have insulation properties. The solder feet 13 can prevent the frame 12 from contacting the periphery of the vibrating plate 11 and short-circuiting.

[0050] Next, Figure 7 This is a cross-sectional view of the fluid control device 1A in Modified Example 1. For... Figure 1 The same structures are labeled with the same reference numerals in the attached figures, and the descriptions are omitted. Figure 8 This is a bottom view of the piezoelectric element 10 in the fluid control device 1A.

[0051] In the fluid control device 1A of Modified Example 1, the electrode disposed on the lower surface (first main surface) is divided into an inner peripheral electrode 14A and an outer peripheral electrode 14B when viewed from above.

[0052] During the polling process of the piezoelectric body 10, the inner peripheral electrode 14A and the outer peripheral electrode 14B are applied with driving voltages of opposite polarities based on the potential of the second electrode 15. Therefore, in the piezoelectric body 10, the polarization directions of the inner and outer peripheral portions are opposite.

[0053] Figure 9This is a cross-sectional view of the vibrating plate 11 in the fluid control device 1A during bending vibration. If the inner circumference of the piezoelectric element 10 is as... Figure 9 When the piezoelectric material 10 extends in a direction parallel to the main surface, the inner peripheral portion of the upper surface of the vibrating plate 11 undergoes a convex bending deformation towards the upper surface. On the other hand, at least a portion of the outer periphery of the vibrating plate 11 is fixed by the frame 12 and frame 17, so the outer peripheral portion of the upper surface of the vibrating plate 11, unlike the inner peripheral portion, undergoes a convex bending deformation towards the lower surface. At this time, assuming the entire piezoelectric material 10 extends in a direction parallel to the main surface, the piezoelectric material 10 applies a force to its outer peripheral portion in a direction opposite to the bending direction of the upper surface of the vibrating plate 11. Furthermore, although not shown, if the inner peripheral portion of the piezoelectric material 10 contracts in a direction parallel to the main surface, the inner peripheral portion of the upper surface of the vibrating plate 11 undergoes a concave bending deformation towards the lower surface, while the outer peripheral portion of the upper surface of the vibrating plate 11, unlike the inner peripheral portion, undergoes a convex bending deformation towards the upper surface. At this time, assuming that the entire piezoelectric body 10 contracts in a direction parallel to the main surface, the piezoelectric body 10 applies a force in the outer peripheral portion in a direction opposite to the bending direction of the upper surface of the vibrating plate 11.

[0054] In contrast, in the fluid control device 1A of this modified example 1, the polarization directions of the inner and outer peripheral portions of the piezoelectric body 10 are opposite. Therefore, if the inner peripheral portion of the piezoelectric body 10 extends in a direction parallel to the main surface, the outer peripheral portion of the piezoelectric body 10 contracts in a direction parallel to the main surface. Furthermore, if the inner peripheral portion of the piezoelectric body 10 contracts in a direction parallel to the main surface, the outer peripheral portion of the piezoelectric body 10 extends in a direction parallel to the main surface.

[0055] Therefore, in the fluid control device 1A of this modified example 1, the bending direction of the vibrating plate and the direction of the force applied to the vibrating plate by the expansion and contraction of the piezoelectric body 10 are consistent in the inner and outer peripheral portions. As a result, in the fluid control device 1A of this modified example 1, the amplitude of the vibrating plate 11 with the same voltage can be increased.

[0056] Next, Figure 10 This is a cross-sectional view of the fluid control device 1B in variant example 2. For... Figure 7 The same structures are labeled with the same reference numerals in the attached figures, and the descriptions are omitted.

[0057] In the fluid control device 1B, a first vibrating plate 11A is adhered to the lower surface (first main surface) of the piezoelectric body 10 using adhesive, and a second vibrating plate 11B is adhered to the upper surface (second main surface) of the piezoelectric body 10 using adhesive. A frame 12 is adhered to the upper surface of the second vibrating plate 11B using adhesive. The second vibrating plate 11B is thinner than the first vibrating plate 11A, and therefore is easily deformed.

[0058] In the fluid control device 1B of Modified Example 2, if a driving voltage is applied to extend the inner peripheral portion of the piezoelectric body 10 in a direction parallel to the main surface, the center of the second vibrating plate 11B will bend in a convex shape toward the upper surface. If a driving voltage is applied to contract the inner peripheral portion of the piezoelectric body 10 in a direction parallel to the main surface, the center of the second vibrating plate 11B will bend in a concave shape toward the lower surface.

[0059] In the fluid control device 1B of Modified Example 2, the component that engages with the frame 12 becomes the second vibrating plate 11B. Therefore, the mechanical stress generated at the engagement position with the frame 12 is mainly applied to the second vibrating plate 11B, and the mechanical stress applied to the piezoelectric element 10 is reduced. In other words, in the fluid control device 1B, the mechanical stress on the piezoelectric element 10 caused by deformation can be reduced, thus suppressing cracks in the piezoelectric element 10.

[0060] Next, Figure 11 This is a cross-sectional view of the fluid control device 2 according to the second embodiment. (For comparison with...) Figure 10 The fluid control device 1B shown has the same structure and is labeled with the same reference numerals, so the description is omitted. The fluid control device 2 includes a first piezoelectric element 10A, a first vibrating plate 11A, a second vibrating plate 11B, a frame 12, a welding foot 13, a first electrode 14, a second inner peripheral electrode 15A, a second outer peripheral electrode 15B, a second piezoelectric element 10B, a third vibrating plate 11C, a third electrode 151, a fourth inner peripheral electrode 152A, a fourth outer peripheral electrode 152B, and a frame 17.

[0061] The first piezoelectric body 10A has the same structure and function as the piezoelectric body 10 of the first embodiment. The second piezoelectric body 10B has the same structure as the first piezoelectric body 10A. The second piezoelectric body 10B has a third main surface and a fourth main surface. A third electrode 151 is formed on the third main surface of the second piezoelectric body 10B, for example by sputtering or the like, and a fourth inner peripheral electrode 152A and a fourth outer peripheral electrode 152B are formed on the fourth main surface, for example by sputtering or the like. A second vibrating plate 11B is attached to the fourth inner peripheral electrode 152A and the fourth outer peripheral electrode 152B by an adhesive.

[0062] A second vibrating plate 11B is attached to the third electrode 151 with an adhesive. A third vibrating plate 11C is attached to the fourth inner peripheral electrode 152A and the fourth outer peripheral electrode 152B with an adhesive.

[0063] Weld feet 13 are formed between the main surface of the first vibrating plate 11A and the side surface of the frame 17, between the main surface of the first piezoelectric body 10A and the main surface of the first vibrating plate 11A, between the main surface of the first piezoelectric body 10A and the main surface of the second vibrating plate 11B, between the main surface of the second piezoelectric body 10B and the main surface of the second vibrating plate 11B, between the main surface of the second piezoelectric body 10B and the main surface of the third vibrating plate 11C, and between the main surface of the third vibrating plate 11C and the side surface of the frame 17.

[0064] The third vibrating plate 11C is circular. In this embodiment, the first vibrating plate 11A, the second vibrating plate 11B, and the third vibrating plate 11C have the same shape when viewed from above, and have the same outer diameter.

[0065] In addition, in this embodiment, when viewed from above, the outer diameters of the first piezoelectric body 10A and the second piezoelectric body 10B are smaller than the outer diameters of the first vibrating plate 11A, the second vibrating plate 11B, and the third vibrating plate 11C.

[0066] In this embodiment, the first vibrating plate 11A, the second vibrating plate 11B, and the third vibrating plate 11C are all of the same shape and have the same outer diameter. The thicknesses of the first vibrating plate 11A, the second vibrating plate 11B, and the third vibrating plate 11C are also the same. However, the second vibrating plate 11B may be thinner or thicker than the first vibrating plate 11A and the third vibrating plate 11C.

[0067] A driving voltage is applied to the first vibrating plate 11A, the second vibrating plate 11B, and the third vibrating plate 11C. A driving voltage at a frequency matching the resonant frequency of the actuator is applied to the first vibrating plate 11A, the second vibrating plate 11B, and the third vibrating plate 11C. This driving voltage is applied to the first electrode 14, the second inner peripheral electrode 15A, the second outer peripheral electrode 15B, the third electrode 151, the fourth inner peripheral electrode 152A, and the fourth outer peripheral electrode 152B.

[0068] The first piezoelectric element 10A and the second piezoelectric element 10B have opposite polarization directions during the polling process. Furthermore, the polarization directions during the polling process are also opposite in the inner and outer peripheral portions of the first piezoelectric element 10A. Similarly, the polarization directions during the polling process are also opposite in the inner and outer peripheral portions of the second piezoelectric element 10B.

[0069] Figure 12 This is a cross-sectional view of the fluid control device 2 during bending vibration. Figure 12In the example, the inner peripheral portion of the first piezoelectric body 10A contracts in a direction parallel to the main surface, and the outer peripheral portion of the first piezoelectric body 10A extends in a direction parallel to the main surface. Similarly, the inner peripheral portion of the second piezoelectric body 10B extends in a direction parallel to the main surface, and the outer peripheral portion of the first piezoelectric body 10A contracts in a direction parallel to the main surface.

[0070] In this case, the inner periphery of the third vibrating plate 11C undergoes a convex bending deformation towards its upper surface, while the outer periphery of the third vibrating plate 11C undergoes a concave bending deformation towards its lower surface. The inner periphery of the first vibrating plate 11A undergoes a concave bending deformation towards its upper surface, while the outer periphery of the first vibrating plate 11A undergoes a convex bending deformation towards its lower surface. The center position of the second vibrating plate 11B in the vertical direction becomes a neutral surface where the stress in the direction parallel to the main surface is approximately zero.

[0071] The outer diameters of the first vibrating plate 11A, the third vibrating plate 11C, the first piezoelectric element 10A, and the second piezoelectric element 10B are larger than the inner diameters of the frame 12 and the frame 17. Therefore, the fluid control device 2 can form a pump chamber through the inner circumferential side of the frame 12 or the frame 17, and the lower surface of the first vibrating plate 11A or the upper surface of the third vibrating plate 11C.

[0072] Vibrating plates are arranged on the two main surfaces of the first piezoelectric element 10A and the second piezoelectric element 10B in the fluid control device 2. Therefore, even if the amplitude of the actuator is increased to improve the output, the piezoelectric element is not at risk of breakage. In particular, the outer diameters of the first piezoelectric element 10A and the second piezoelectric element 10B in the fluid control device 2, when viewed from above, are smaller than the outer diameters of the first vibrating plate 11A and the third vibrating plate 11C. Therefore, during drops or handling, especially the sides of the first piezoelectric element 10A and the second piezoelectric element 10B, there will be no direct contact, thus further suppressing breakage.

[0073] Furthermore, in the fluid control device 2 of this embodiment, solder feet 13 are formed between the main surface of the first vibrating plate 11A and the side surface of the frame 17, between the main surface of the first piezoelectric element 10A and the main surface of the first vibrating plate 11A, between the main surface of the first piezoelectric element 10A and the main surface of the second vibrating plate 11B, between the main surface of the second piezoelectric element 10B and the main surface of the second vibrating plate 11B, between the main surface of the second piezoelectric element 10B and the main surface of the third vibrating plate 11C, and between the main surface of the third vibrating plate 11C and the side surface of the frame 12. Solder feet 13 are formed by the exposure of the aforementioned adhesive. Therefore, it is possible to prevent short circuits caused by contact between the peripheral portions of the first vibrating plate 11A, the second vibrating plate 11B, and the third vibrating plate 11C.

[0074] The fluid control device 2 constitutes the actuator of the piezoelectric dual crystal oscillator. Compared with the fluid control devices 1, 1A, and 1B that constitute the actuator of the piezoelectric single crystal oscillator, the actuator of the piezoelectric dual crystal oscillator can be efficiently converted into bending vibration even with the same driving voltage, and the amplitude per voltage can be increased.

[0075] Figure 13 This is a graph showing the relationship between the distance of the piezoelectric element's principal face (the principal face furthest from the central face) from the central face and the stress / amplitude (stress per amplitude). Figure 14 This is a diagram showing the relationship between the distance from the main surface of the piezoelectric element to the neutral surface and the amplitude. Figure 15 It is a graph showing the relationship between the amplitude and the radial stress at the center of the piezoelectric material. Figure 13 The stress shown is the stress generated tangentially from the main surface of the piezoelectric element at the center when viewed from above. Figure 15 The stress shown is the stress generated radially (planar direction) from the main surface of the piezoelectric element at the center when viewed from above. Figure 13 , Figure 14 as well as Figure 15 The single piezoelectric crystal shown represents the structure of fluid control device 1B, while the dual piezoelectric crystals correspond to the structure of fluid control device 2. In both structures, the thickness of the vibrating plate is adjusted in such a way that the actuator's resonant frequency remains constant.

[0076] like Figure 13 As shown, regardless of whether it's a single or double piezoelectric crystal, the greater the distance between the principal surface of the piezoelectric material and the intermediate surface, the greater the stress per amplitude. Furthermore, if the distance between the principal surface of the piezoelectric material and the intermediate surface is the same, the stress generated by the piezoelectric material is slightly greater in the case of a single piezoelectric crystal (and smaller in the case of a double piezoelectric crystal). On the other hand, as... Figure 14 As shown, if the distance between the main surface and the intermediate surface of the piezoelectric material is the same, the amplitude of the actuator is much larger in the case of two piezoelectric crystals. Furthermore, as... Figure 15 As shown, if the radial stress at the center of the piezoelectric material is the same, the amplitude of the actuator is much larger in the case of two piezoelectric crystals.

[0077] In a single piezoelectric crystal, the bending vibration is hindered by the vibrating plates attached to the two main faces of the piezoelectric element, while the stretching vibration component increases. In contrast, even in a dual piezoelectric crystal, where vibrating plates are attached to the two main faces of the piezoelectric element, the stretching and contraction of the paired piezoelectric elements in opposite directions can be efficiently converted into bending vibration. Therefore, in a dual piezoelectric crystal, the outermost vibrating plate of the actuator can be thickened for resonant frequency adjustment. Consequently, compared to a single piezoelectric crystal, the neutral plane is closer to the main face of the piezoelectric element, thus reducing the stress per amplitude of the piezoelectric element. In other words, even with the same stress, the amplitude of the actuator is much larger in the case of a dual piezoelectric crystal.

[0078] Therefore, in a dual piezoelectric crystal such as fluid control device 2, compared with a single piezoelectric crystal such as fluid control devices 1, 1A, and 1B, the piezoelectric element is less likely to be damaged when the output is increased and the amplitude is increased.

[0079] Next, Figure 16 This is a cross-sectional view showing the structure of a modified example 1 of a dual piezoelectric wafer. Figure 16 In the fluid control device 2A of Modified Example 1, the outer diameters of the first piezoelectric element 10A and the second piezoelectric element 10B, viewed from above, are larger than the outer diameter of the second vibrating plate 11B. Therefore, the first piezoelectric element 10A exists between the ends of the first vibrating plate 11A and the second vibrating plate 11B, and the second piezoelectric element 10B exists between the ends of the third vibrating plate 11C and the second vibrating plate 11B. Thus, the possibility of contact between the first vibrating plate 11A and the second vibrating plate 11B, and between the third vibrating plate 11C and the second vibrating plate 11B, is further reduced during vibration, and the possibility of short circuits can be further suppressed.

[0080] Next, Figure 17 This is a cross-sectional view showing the structure of a modified example 2 of a dual piezoelectric wafer. Figure 17 In the fluid control device 2B of Modified Example 2, the outer diameters of the first piezoelectric element 10A, the second piezoelectric element 10B, the first vibrating plate 11A, the second vibrating plate 11B, and the third vibrating plate 11C are all the same when viewed from above.

[0081] In the fluid control device 2B, weld feet 13 are also formed between the main surface of the first vibrating plate 11A and the side surface of the frame 17, between the main surface of the first piezoelectric element 10A and the main surface of the first vibrating plate 11A, between the main surface of the first piezoelectric element 10A and the main surface of the second vibrating plate 11B, between the main surface of the second piezoelectric element 10B and the main surface of the second vibrating plate 11B, between the main surface of the second piezoelectric element 10B and the main surface of the third vibrating plate 11C, and between the main surface of the third vibrating plate 11C and the side surface of the frame 12. In the fluid control device 2B, vibrating plates are also arranged on the two main surfaces of each of the first piezoelectric element 10A and the second piezoelectric element 10B. Therefore, even if the amplitude of the actuator is increased to improve output, there is no risk of the piezoelectric element breaking.

[0082] Next, Figure 18 This is an exploded perspective view showing the structure of Modified Example 3 of the dual piezoelectric wafer. The fluid control device 2C of Modified Example 3 has a rectangular shape in top view. In addition to its rectangular shape in top view, the fluid control device 2C possesses... Figure 17 The fluid control device 2B shown has the same structure and function. Thus, the shape of the fluid control device of this invention in top view can also be rectangular.

[0083] Next, Figure 19 This is an exploded perspective view of the fluid control device 2D of Modified Example 4. The fluid control device 2D further includes a connecting member 81, a diaphragm valve 82, a plate 83, a flow path forming member 84, a cover member 85, and a cover 90. The connecting member 81, the diaphragm valve 82, the plate 83, the flow path forming member 84, and the cover member 85 are arranged in this order below the first vibrating plate 11A. Figure 20 as well as Figure 21 This is a cross-sectional view showing the portion below the first vibrating plate 11A in the fluid control device 2D. Furthermore, in Figure 20 , Figure 21 The illustration of the cover component 85 is omitted in the text.

[0084] The diaphragm valve 82 is made of a flexible material and is in the shape of a circular plate. Viewed from above, the diaphragm valve 82 is positioned at the center of the first vibrating plate 11A. The diaphragm valve 82 engages with the lower surface of the first vibrating plate 11A via a circular plate-shaped engaging member 81. The outer diameter of the diaphragm valve 82 is larger than the outer diameter of the engaging member 81. That is, the area at the outer end of the diaphragm valve 82 is not engaged. Thus, the diaphragm valve 82 engages with the first vibrating plate 11A in a vibrating state within a predetermined area at its outer end. Furthermore, the diaphragm valve 82 is not limited to a circular plate shape; it can also be an annular shape.

[0085] Plate 83 is a plate-shaped component. Viewed from above, plate 83 has through holes at its center and near its outer periphery. Plate 83 is configured separately from diaphragm valve 82. Plate 83 as... Figure 6 As described, it is flexible and vibrates due to pressure changes in the pump chamber that accompany the vibration of the first vibrating plate 11A.

[0086] The flow path forming component 84 is a plate-shaped component. The recessed portion of the flow path forming component 84, viewed from above, consists of a circular central region and multiple linear regions. The central region, viewed from above (along the stacking direction of the plate 83 and the flow path forming component 84), overlaps with the through-hole formed in the plate 83. One end of each of the multiple linear regions extends into the central region, while the other end reaches the vicinity of distinct outer ends in the flow path forming component 84. Through these central region, the multiple linear regions, and the plate 83, a flow path communicating with the central part of the pump chamber is formed.

[0087] The cover component 85 is a plate-shaped component. The cover component 85 has a hole. The hole extends through the cover component 85 in the thickness direction.

[0088] If the center of the first vibrating plate 11A is far away from the plate 83, then as Figure 21As shown, the region on the outer edge (free end side) of the diaphragm valve 82 bends towards the plate 83 and abuts against the surface of the plate 83. This blocks the flow path connecting the outer periphery and center of the plate 83, inhibiting the inflow of fluid from the outer periphery of the pump chamber to the center. In this way, the diaphragm valve 82 constitutes a flow rectifying mechanism.

[0089] Therefore, the fluid control device 2D of Modified Example 4 can improve its performance as a pump.

[0090] Figure 22 This is a 2D top view of the fluid control device. Figure 23 It is a 2D stereoscopic view of a fluid control device.

[0091] The cover component 85 is disposed on the lowest surface of the fluid control device 2D. The cover component 85 forms part of the housing of the fluid control device 2D. Through the cover component 85, external objects will not directly contact the components of the fluid control device 2D during drops or handling. Thus, the cover component 85 can prevent damage to the fluid control device 2D.

[0092] The cover 90 is positioned opposite the plate 83 to the third vibrating plate 11C. The cover 90 is disposed on the uppermost surface of the fluid control device 2D. With the cover 90, the third vibrating plate 11C will not directly contact external objects during the drop or handling of the fluid control device 2D. Therefore, the cover 90 can prevent damage to the fluid control device 2D.

[0093] The cover 90 has an opening 90B at its center. The opening 90B overlaps with the center of the third vibrating plate 11C when viewed from above. Therefore, when the third vibrating plate 11C convexly bends towards its upper surface during operation, contact between the upper surface of the third vibrating plate 11C and the cover 90 can be suppressed. In other words, the cover 90 does not obstruct the vibration of the third vibrating plate 11C, thus suppressing any reduction in pump performance.

[0094] The first vibrating plate 11A, the second vibrating plate 11B, and the third vibrating plate 11C each have a first peripheral terminal 110A, 111A, a second peripheral terminal 110B, 111B, and a third peripheral terminal 110C, 111C that protrude outwards to the outer periphery.

[0095] A drive circuit (not shown) is connected to the second outer peripheral terminal 111B and the frame 12. The frame 12 has a bent terminal 120, and the frame 17 has a bent terminal 170. The first vibrating plate 11A and the third vibrating plate 11C are connected via the bent terminal 170 and the bent terminal 120, respectively. Thus, a drive voltage is applied to the first vibrating plate 11A, the second vibrating plate 11B, and the third vibrating plate 11C.

[0096] The first outer peripheral terminals 110A and 111A, the second outer peripheral terminals 110B and 111B, and the third outer peripheral terminals 110C and 111C do not overlap when viewed from above. As a result, the first outer peripheral terminals 110A and 111A, the second outer peripheral terminals 110B and 111B, and the third outer peripheral terminals 110C and 111C will not come into contact with each other, thus suppressing short circuits between terminals.

[0097] Furthermore, when viewed from above, the outer diameter of the cover member 85, which serves as the housing of the fluid control device, is located further outward than the outermost positions of the first outer peripheral terminals 110A, 111A, the second outer peripheral terminals 110B, 111B, and the third outer peripheral terminals 110C, 111C. Therefore, the cover member 85 can suppress short circuits between terminals caused by contact or deformation of the first outer peripheral terminals 110A, 111A, the second outer peripheral terminals 110B, 111B, and the third outer peripheral terminals 110C, 111C during a drop impact.

[0098] The bent terminals 120 and 170 can shorten the path of the terminals leading to the outside, thus suppressing humming caused by unnecessary vibration and the reduction in pump performance caused by vibration leakage.

[0099] The cover has a protrusion 90A that projects outwards from the periphery when viewed from above. The bent terminals 120 and 170 are pressed down by the protrusion 90A in the vertical direction. When the bent terminals 120 and 170 are engaged, the vertical reaction force generated by these bent terminals 120 and 170 is pressed down by the protrusion 90A. Therefore, the strength of the engagement is increased.

[0100] Next, Figure 24 This is a cross-sectional view showing the structure of other variations of the fluid control device. Figure 25 yes Figure 24 A magnified view of a portion of the image.

[0101] The fluid control device 1E of Modified Example 4 is relative to Figure 7 The fluid control device 1A shown differs from the one shown in the location of the circuit board and the shape of the electrode film formed on the piezoelectric body 10. The other structures of the fluid control device 1E are the same as those of the fluid control device 1A, and descriptions of the same parts are omitted.

[0102] The fluid control device 1E includes a piezoelectric element 10, a frame 12, solder feet 13, a frame 17, and a circuit board 18. The piezoelectric element 10 includes a main surface F101, a main surface F102, and a side surface F103.

[0103] An inner peripheral electrode 14EA and an outer peripheral electrode 14EB are formed on the main surface F101. The outer peripheral electrode 14EB is not shaped to reach the side surface F103.

[0104] A second electrode 15E is formed on the main surface F102 and the side surface F103. The second electrode 15E is shaped to reach the corner where the side surface F103 intersects with the main surface F101.

[0105] The circuit board 18 is mainly composed of a laminate of insulating layers 181 and 182. An electrode pattern D181 is formed between insulating layers 181 and 182. Electrode patterns D1821 and D1822 are formed on the side of insulating layer 182 opposite to the side of insulating layer 181. Electrode patterns D1821 and D1822 are separated from each other. Electrode pattern D1822 is electrically connected to electrode pattern D181 through a plurality of through-hole electrodes VIA18 formed in insulating layer 182.

[0106] The piezoelectric element 10 is mounted on the circuit board 18. The inner peripheral electrode 14EA and the outer peripheral electrode 14EB of the piezoelectric element 10 are electrically connected to the electrode pattern D1822. The second electrode 15E of the piezoelectric element 10 is electrically connected to the electrode pattern D1821.

[0107] With this structure, an AC voltage is applied to the inner peripheral electrode 14EA and the outer peripheral electrode 14EB of the piezoelectric body 10 through the electrode pattern D1822, the multiple through-hole electrodes VIA18, and the electrode pattern D181 of the circuit board 18. An AC voltage is applied to the second electrode 15E of the piezoelectric body 10 through the electrode pattern D1821.

[0108] Based on the above structure, the circuit board 18 is a flat plate with a specified stiffness (elasticity). Therefore, the circuit board 18 functions as a vibrating plate. As a result, the fluid control device 1E can realize an actuator.

[0109] Solder pin 13 covers the electrode pattern D1821 of the circuit board 18 and the side surface F103 of the piezoelectric body 10. This can suppress short circuits between the electrode pattern D1821 and the frame 12.

[0110] With this structure, the fluid control device 1E can achieve the same effect as the fluid control device 1A. Furthermore, the fluid control device 1E uses a circuit board that applies AC voltage to the inner peripheral electrode 14EA, outer peripheral electrode 14EB, and second electrode 15E of the piezoelectric body 10 as a vibrating plate. Thus, the fluid control device 1E includes an AC voltage application mechanism, which simplifies the structure.

[0111] Furthermore, in the embodiments described above, the inner circumferential surface of the frame is shown to be circular when viewed from above, but this is not a limitation. For example, the shape of the inner circumferential surface of the frame when viewed from above can also be elliptical or a regular polygon. In the case of an ellipse, the inner diameter represents the major axis; in the case of a regular polygon, the inner diameter corresponds to the length of the diagonal.

[0112] Similarly, in various embodiments, the piezoelectric element and the vibrating plate are shown to be circular in plan view, but are not limited to this. In this case, for example, the outer diameter corresponds to the shortest distance from the center (the center of the shape of the inner circumferential surface of the frame in plan view) when the actuator composed of the piezoelectric element and the vibrating plate is configured with a frame.

[0113] The description of this embodiment should be considered illustrative in all respects and not as a limitation of the invention. The scope of the invention is defined not by the above-described embodiments, but by the claims. Furthermore, the scope of the invention is intended to include equivalents to the claims and all modifications within that scope.

[0114] Explanation of reference numerals in the attached figures

[0115] 1, 1A, 1B, 1E, 2, 2A, 2C, 2D… Fluid control device; 10… Piezoelectric element; 10A… First piezoelectric element; 10B… Second piezoelectric element; 11… Vibrating plate; 11A… First vibrating plate; 11B… Second vibrating plate; 11C… Third vibrating plate; 12… Frame; 13… Welding foot; 14… First electrode; 14A, 14EA… Inner peripheral electrode; 14B, 14EB… Outer peripheral electrode; 15… Second electrode; 15A… Second inner peripheral electrode; 15B… Second outer peripheral electrode; 17… Frame; 18… Circuit board; 81… Joining component; 82…Thin-film valve; 83…Plate; 84…Flow path forming component; 85…Cover component; 90…Cover; 90A…Protrusion; 90B…Opening; 110A, 111A…First outer peripheral terminal; 110B, 111B…Second outer peripheral terminal; 110C, 111C…Third outer peripheral terminal; 120…Bent terminal; 151…Third electrode; 152A…Fourth inner peripheral electrode; 152B…Fourth outer peripheral electrode; 170…Bent terminal; 181, 182…Insulating layer; D1821, D1822…Electrode pattern; VIA18…Through-hole electrode.

Claims

1. A fluid control device, comprising: Actuator; and A ring-shaped frame is disposed on the actuator, fixing at least a portion of the outer periphery of the actuator. The actuator includes: a piezoelectric element having a first main surface and a second main surface; and a vibrating plate connected to the first main surface of the piezoelectric element. The frame is disposed on the second main surface. The outer diameter of the vibrating plate and the outer diameter of the piezoelectric element are larger than the inner diameter of the frame. The outer diameter of the vibrating plate or the outer diameter of the frame is larger than the outer diameter of the piezoelectric element.

2. The fluid control device according to claim 1, wherein, A weld foot is formed between the side of the frame and the second main surface of the piezoelectric element, or between the side of the frame and the main surface of the vibrating plate.

3. The fluid control device according to claim 1 or 2, wherein, The electrode disposed on the first main surface of the piezoelectric body or the electrode disposed on the second main surface of the piezoelectric body is divided into an inner peripheral electrode and an outer peripheral electrode when viewed from above.

4. A fluid control device, comprising: Actuator; and A ring-shaped frame is disposed on the actuator, fixing at least a portion of the outer periphery of the actuator. The actuator includes: a piezoelectric element having a first main surface and a second main surface; and a vibrating plate connected to the piezoelectric element. The vibrating plate includes a first vibrating plate connected to the first main surface and a second vibrating plate connected to the second main surface. The frame is disposed on the side opposite to the piezoelectric element in either the first or the second vibrating plate. The outer diameters of the first vibrating plate, the second vibrating plate, and the piezoelectric element are all larger than the inner diameter of the frame. The outer diameter of the first vibrating plate, the outer diameter of the second vibrating plate, or the outer diameter of the frame is larger than the outer diameter of the piezoelectric element.

5. The fluid control device according to claim 4, wherein, A weld foot is formed between the side of the frame and the main surface of the first vibration plate, or between the side of the frame and the main surface of the second vibration plate.

6. The fluid control device according to claim 4 or 5, wherein, The electrode disposed on the first main surface of the piezoelectric body or the electrode disposed on the second main surface of the piezoelectric body is divided into an inner peripheral electrode and an outer peripheral electrode when viewed from above.

7. The fluid control device according to any one of claims 4 to 6, wherein, The piezoelectric body comprises: a first piezoelectric body having a first main surface and a second main surface; and a second piezoelectric body having a third main surface and a fourth main surface. The second vibrating plate is further disposed on the third main surface. The vibrating plate further includes a third vibrating plate disposed on the fourth main surface. The frame includes a first frame connected to the first vibrating plate and a second frame connected to the third vibrating plate.

8. The fluid control device according to claim 7, wherein, Viewed from above, the outer diameters of the first piezoelectric element and the second piezoelectric element are smaller than the outer diameters of the first vibrating plate, the second vibrating plate, and the third vibrating plate.

9. The fluid control device according to claim 7 or 8, wherein, Viewed from above, the outer diameter of the second vibrating plate is smaller than that of the first and third vibrating plates.

10. The fluid control device according to any one of claims 7 to 9, wherein, It has a flat plate opposite to the first vibrating plate.

11. The fluid control device according to claim 10, wherein, It has a rectifier mechanism configured between the flat plate and the first vibrating plate.

12. The fluid control device according to claim 10, wherein, It has a cover, which is located on the opposite side of the flat plate and opposite to the third vibrating plate.

13. The fluid control device according to claim 12, wherein, The cover has an opening.

14. The fluid control device according to any one of claims 7 to 13, wherein, It has a first peripheral terminal, a second peripheral terminal, and a third peripheral terminal protruding to the outer peripheral side of the first vibrating plate, the second vibrating plate, and the third vibrating plate, respectively. The first outer peripheral terminal, the second outer peripheral terminal, and the third outer peripheral terminal do not overlap when viewed from above.

15. The fluid control device according to claim 14, wherein, Viewed from above, the outer diameter of the housing of the fluid control device is located closer to the outermost position than the first outer peripheral terminal, the second outer peripheral terminal, and the third outer peripheral terminal.

16. The fluid control device according to any one of claims 7 to 15, wherein, The first frame or the second frame has a bent terminal. The first vibrating plate and the third vibrating plate are connected via the bending terminal.

17. The fluid control device according to claim 16, wherein, The fluid control device includes: A flat plate, opposite to the first vibrating plate; and The cover, located on the opposite side of the flat plate, is opposite to the third vibrating plate. The cover has a protrusion that projects outwards to the outer periphery when viewed from above. The bent terminal is pressed by the protrusion.

18. The fluid control device according to any one of claims 7 to 15, wherein, The pump chamber is formed by the space surrounded by the inner side of the frame, the first vibrating plate, and the surface opposite the first vibrating plate.

19. The fluid control device according to any one of claims 1 to 18, wherein, The vibrating plate is composed of a circuit board. The circuit board has an insulating layer and an electrode pattern that is connected to the electrodes of the piezoelectric element.

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