JP6263902B2 - Ultrasonic generator - Google Patents

Description

  The present invention relates to an ultrasonic generator that emits ultrasonic waves by vibration of a diaphragm, and more particularly to an ultrasonic generator having a piezoelectric diaphragm utilizing a piezoelectric effect.

  Conventionally, various vibration devices and ultrasonic generators using piezoelectric vibrators have been proposed. The following Patent Document 1 discloses a vibration device having a drip-proof function. The vibration device includes a first piezoelectric diaphragm disposed substantially flush with an outer surface of the casing, and a second piezoelectric diaphragm disposed in the casing with a gap between the first piezoelectric diaphragm and the first piezoelectric diaphragm. Have The first piezoelectric diaphragm is used as a sound emitting plate. The outer peripheral edge of the first piezoelectric diaphragm and the outer peripheral edge of the second piezoelectric diaphragm are connected by a side wall member. The first piezoelectric diaphragm and the second piezoelectric diaphragm are driven in opposite phases.

Japanese Patent No. 3986987

  The vibration device described in Patent Document 1 has a problem that the resonance frequency is not stable. Therefore, the resonance frequency tends to fluctuate depending on how the casing is attached.

  In addition, since the first and second piezoelectric diaphragms and the side wall member vibrate, the output efficiency of vibration was low. If the acoustic impedance of the sound emitting plate is made close to the acoustic impedance of the air, the output efficiency of the ultrasonic wave can be increased, but the output efficiency cannot be increased because the sound emitting plate is composed of the first piezoelectric diaphragm. It was.

  An object of the present invention is to provide a high-power ultrasonic generator that is less susceptible to frequency fluctuations due to support.

  The ultrasonic generator according to the present invention includes a first plate-like body, a second plate-like body, an intermediate diaphragm, and an outer peripheral side wall. The second plate-like body is arranged so as to be separated from the first plate-like body so that the main surfaces thereof face each other. The intermediate diaphragm is disposed between the first plate and the second plate. The intermediate diaphragm is disposed so as to face the first and second plate-like bodies. The outer peripheral side wall connects the outer peripheral edges of the first plate-like body, the intermediate diaphragm, and the second plate-like body.

  In the present invention, the intermediate diaphragm is a piezoelectric diaphragm that vibrates in a bending mode. The intermediate diaphragm and the first and second plate-like bodies are the outer peripheral side walls so that the first and second plate-like bodies vibrate antisymmetrically with respect to the vibration of the intermediate diaphragm. It is connected by.

  On the specific situation with the ultrasonic generator which concerns on this invention, a said 1st plate-shaped body is a non-driving member which vibrates with the vibration of the said intermediate diaphragm. In this case, the material of the non-driving member can be selected from a wide range of materials. Therefore, the first plate-like body can be made of a material having an acoustic impedance value close to the acoustic impedance of the surrounding material such as air. Therefore, the output efficiency can be further increased.

  In another specific aspect of the ultrasonic generator according to the present invention, the acoustic impedance of the first plate-like body is lower than the acoustic impedance of the intermediate diaphragm.

  In another specific aspect of the ultrasonic generator according to the present invention, the second plate-like body is a driving member that actively vibrates. In this case, since the second plate-like body is also driven actively, the output efficiency can be further improved.

  In still another specific aspect of the ultrasonic generator according to the present invention, the first and second plate-like bodies are drive members that actively vibrate. In this case, since all of the first and second plate-like bodies and the intermediate diaphragm are driven, the output efficiency can be further improved.

  In another specific aspect of the ultrasonic generator according to the present invention, the outer peripheral side wall includes a first space between the first plate-like body and the intermediate diaphragm, the intermediate diaphragm, and the above The entire outer peripheral edges of the first plate, the intermediate diaphragm, and the second plate are connected so as to close the second space between the second plate and the second plate. doing. In this case, since the first and second spaces are closed, it is possible to provide an ultrasonic generator with excellent drip-proof properties.

  In another specific aspect of the ultrasonic generator according to the present invention, a portion of the outer peripheral side wall connected to the intermediate diaphragm is a vibration node. In this case, even if another member such as a support member is connected to the outer surface of the portion connected to the intermediate diaphragm on the outer peripheral side wall, the frequency fluctuation hardly occurs. Therefore, the output efficiency is hardly lowered.

  In still another specific aspect of the ultrasonic generator according to the present invention, a support member connected to an outer surface of a portion of the outer peripheral side wall connected to the intermediate diaphragm is further provided. In this case, frequency fluctuation is unlikely to occur. In addition, the output efficiency is hardly lowered. Therefore, the ultrasonic generator according to the present invention can be easily incorporated into the housing of the electronic device or the like via the support member.

  In still another specific aspect of the ultrasonic generator according to the present invention, a holding member connected to the support member is further provided. In this case, the ultrasonic generator can be connected to the casing of the electronic device via the holding member.

  In still another specific aspect of the ultrasonic generator according to the present invention, the holding member surrounds a structure having the first and second plate-like bodies, the intermediate diaphragm, and the outer peripheral side wall. It is the frame-shaped holding member provided. In this case, the vibration part including the first plate, the intermediate vibration plate, the second plate, and the outer peripheral side wall can be protected from the outside by the frame-shaped holding member. Further, the ultrasonic generator can be easily and reliably fixed to a case of an electronic device.

  According to the ultrasonic generator of the present invention, the first and second plate-like bodies vibrate in a mode that is antisymmetric with respect to the intermediate diaphragm that vibrates in the bending mode. Even if it is supported, frequency fluctuation is unlikely to occur. In addition, the output efficiency is hardly lowered. Accordingly, it is possible to provide a high-output ultrasonic generator that hardly generates output fluctuations.

1 is a plan view of an ultrasonic generator according to a first embodiment of the present invention. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line in FIG. (A) And (b) is each schematic diagram which shows the vibration mode of the ultrasonic generator of this invention. It is a perspective view which shows the external appearance of the ultrasonic generator of the 2nd Embodiment of this invention. It is front sectional drawing of the ultrasonic generator which concerns on the 2nd Embodiment of this invention. It is a partial notch cross-sectional perspective view which shows the vibration part in the 2nd Embodiment of this invention. It is a partial notch top sectional view for demonstrating the principal part of the ultrasonic generator of the 2nd Embodiment of this invention. It is front sectional drawing which shows the principal part of the ultrasonic generator which concerns on the 3rd Embodiment of this invention. It is front sectional drawing which shows the principal part of the ultrasonic generator which concerns on the 4th Embodiment of this invention.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

  1 is a plan view of the ultrasonic generator according to the first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is taken along line BB. It is sectional drawing which follows.

  The ultrasonic generator 1 has a vibrating body 2. The vibrating body 2 includes a first plate-like body 3, a second plate-like body 4, and an intermediate diaphragm 5. The first plate-like body 3 and the second plate-like body 4 are arranged so that the main surfaces face each other. The intermediate diaphragm 5 is disposed between the first plate-like body 3 and the second plate-like body 4. The intermediate diaphragm 5 faces the first plate 3 with the first space 6 therebetween. Further, the intermediate diaphragm 5 is opposed to the second plate 4 via the second space 7. The first outer peripheral side wall 8 is connected to the outer peripheral edge of the first plate-like body 3. The first outer peripheral side wall portion 8 is integrally formed of the same material as the first plate-like body 3. The first outer peripheral side wall 8 is joined to the upper surface of the intermediate diaphragm 5.

  Similarly, the second outer peripheral side wall 9 is connected to the outer peripheral edge of the second plate-like body 4. The second outer peripheral side wall 9 is joined to the lower surface of the intermediate diaphragm 5. The second outer peripheral side wall portion 9 is integrally formed of the same material as the second plate-like body 4.

  In the present embodiment, the first and second outer peripheral side wall portions 8 and 9 constitute the outer peripheral side wall portion of the present invention. But the outer peripheral side wall part may be comprised with the material different from the 1st, 2nd plate-shaped bodies 3 and 4. FIG.

  In the present embodiment, the first plate-like body 3 is made of an appropriate insulating material such as ceramics or rigid resin. Alternatively, the first and second plate-like bodies 3 and 4 may be made of a material in which an insulating film is formed on the surface of the metal plate.

  Preferably, in order to emit an ultrasonic wave as indicated by an arrow D in FIG. 2, the first plate-like body 3 located on the sound emission side is preferably made of a material having an acoustic impedance value close to the impedance of air. . Therefore, the first plate-like body 3 is preferably made of a material having an acoustic impedance value lower than the acoustic impedance value of the intermediate diaphragm 5 described later.

  On the other hand, the intermediate diaphragm 5 includes a rectangular plate-shaped piezoelectric body 10, a metal plate 11, and an electrode 13. The piezoelectric body 10 is made of, for example, a piezoelectric ceramic such as PZT. A metal plate 11 is bonded to the upper surface of the piezoelectric body 10. Lead terminals 12 provided integrally with the metal plate 11 are connected to the metal plate 11. On the other hand, an electrode 13 is formed on the lower surface of the piezoelectric body 10. A lead terminal 15 is connected to the electrode 13 through a conducting portion 13a shown in FIG.

  In this embodiment, the piezoelectric body 10 is bonded to the metal plate 11 to constitute a unimorph type piezoelectric diaphragm. Further, the metal plate 11 also serves as one electrode. That is, by applying an AC electric field between the metal plate 11 and the electrode 13, the intermediate diaphragm 5 which is a unimorph type piezoelectric diaphragm is configured to vibrate in a bending mode.

  In the present embodiment, the first and second outer peripheral side wall portions 8 and 9 constitute an outer peripheral side wall. The outer peripheral side wall is provided so as to surround a portion where the first plate-like body 3, the second plate-like body 4, and the intermediate diaphragm 5 are laminated. Therefore, in the present embodiment, the first space 6 and the second space 7 are closed. Therefore, moisture and moisture are hardly generated in the vibrating body, and the drip-proof property is excellent.

  Furthermore, the metal plate 11 also serves as the support member of the present invention in this embodiment. That is, a portion 11 a extending outward from the outer peripheral side wall of the metal plate 11 also serves as a support member for the vibrating body 2. The portion 11 a serving also as the support member is located outside the portion connected to the outer peripheral side wall of the intermediate diaphragm 5. In the present embodiment, the portion of the outer peripheral side wall located outside the intermediate diaphragm 5 is a vibration node. Therefore, even if the vibrating body 2 is supported by the portion 11a that also serves as a support member, the frequency variation of the ultrasonic waves in the ultrasonic generator 1 hardly occurs. In addition, the output efficiency is hardly lowered.

  A portion 11 a that also serves as a support member of the metal plate 11 reaches the frame-shaped holding member 17. In this frame-shaped holding member 17, a portion 11a that also serves as the support member is connected to the lead terminal 12 that extends downward in FIG. The end portion of the lead terminal 12 protrudes from the lower surface of the frame-shaped holding member 17 to the outside of the frame-shaped holding member 17.

  On the other hand, the electrode 13 is joined to the lead terminal 15 via the conducting portion 13a. The lead terminal 15 is embedded in the frame-shaped holding member 17 so as to extend in the vertical direction in FIG. The outer end of the lead terminal 15 protrudes from the lower surface of the frame-shaped holding member 17 to the outside of the frame-shaped holding member 17.

  The frame-shaped holding member 17 is made of an appropriate molding resin material such as a liquid crystal polymer.

  The metal plate 11 is made of an appropriate metal plate such as stainless steel. When the metal plate 11 is made of stainless steel, moisture resistance can be effectively enhanced. But the metal plate 11 can consist of appropriate metal materials, such as Al, Cu, or an alloy containing these. The lead terminal 12, the electrode 13, and the lead terminal 15 can also be made of an appropriate metal material.

  As shown in FIG. 1, the vibrating body 2 is separated from the frame-shaped holding member 17 via a surrounding rectangular plate-shaped space 18. Therefore, even if the frame-shaped holding member 17 is connected to the case or the like of the electronic device, the vibrating body 2 does not contact the case or the like of the electronic device.

  Further, the height-direction dimension of the frame-shaped holding member 17 is larger than the height-direction dimension of the vibrator 2. Therefore, the vibrating body 2 can be reliably protected by the frame-shaped holding member 17.

  However, the frame-shaped holding member 17 is not necessarily provided, and the shape of the frame-shaped holding member 17 is not particularly limited.

  In the present invention, the holding member does not necessarily have a closed frame shape. The holding member may have a shape in which a part of the closed frame shape is cut out. Moreover, the holding member which does not have frame shape itself may be sufficient.

  Next, the vibration mode of the vibrating body 2 will be described with reference to FIGS. 4 (a) and 4 (b). In the vibrating body 2, an alternating electric field is applied between the lead terminal 12 and the lead terminal 15 in FIG. 1. As a result, since the intermediate diaphragm 5 is a unimorph type piezoelectric diaphragm, it vibrates in a bending mode. When the intermediate diaphragm 5 vibrates in the bending mode, the first and second plate-like bodies 3 and 4 are antisymmetric with respect to the intermediate diaphragm 5 and resonantly vibrate with the vibration of the intermediate diaphragm 5. As described above, the outer peripheral side wall composed of the outer peripheral side wall portions 8 and 9 connects the first and second plate-like bodies 3 and 4 to the intermediate diaphragm 5.

  Therefore, in this embodiment, when the AC electric field is applied, the vibrating body 2 vibrates so as to alternately take the vibration state shown in FIG. 4A and the vibration state shown in FIG. In FIG. 4A, the displacement states of the first and second plate-like bodies 3 and 4 and the intermediate diaphragm 5 are respectively indicated by solid lines. In addition, each position in a stationary state that does not vibrate is indicated by an alternate long and short dash line.

  As shown in FIGS. 4A and 4B, when the intermediate diaphragm 5 vibrates in the bending mode, the first and second plate-like bodies 3, 4 have a shape that is antisymmetric with the intermediate diaphragm 5. It vibrates like taking.

  When such vibration occurs, ultrasonic waves are emitted from the first plate-like body 3 as indicated by an arrow D in FIG. Note that ultrasonic waves may be emitted from the second plate-like body 4 side. In the present embodiment, the first plate-like body 3 is used so that it is on the outside, that is, on the ultrasonic wave emission side.

  When the vibrating body 2 vibrates after emitting the ultrasonic wave, the vibration node is located at the portion where the intermediate diaphragm 5 of the outer peripheral side wall is connected as described above. Accordingly, vibration hardly leaks into the portion 11a that also serves as a support member. Therefore, since the frequency fluctuation of the emitted ultrasonic wave is hardly changed by the support structure, the output efficiency can be increased.

  In addition, in the present embodiment, since the intermediate diaphragm 5, the first space 6, and the second space 7 are closed, it is difficult for frequency fluctuations due to adhesion of foreign matters, moisture, and the like to occur. This also makes it difficult for the output efficiency to decrease.

  Therefore, it is possible to provide a highly efficient drip-proof ultrasonic generator 1 that hardly causes frequency fluctuations.

  In addition, in the present embodiment, the first plate-like body 3 is not a member driven by positively applying an electric field. That is, the first plate-like body 3 is a non-driving member. Note that the second plate-like body 4 is also a non-driving member.

  When the first plate-like body 3 on the ultrasonic emission side is a non-driving member, the material can be selected from a wide range of materials as described above. Therefore, it is desirable to select the material of the first plate 3 so that the acoustic impedance of the first plate 3 is close to the acoustic impedance of air. Thereby, the output efficiency can be further increased. Therefore, the acoustic impedance of the first plate-like body 3 is preferably close to the acoustic impedance of air, and since the intermediate diaphragm 5 is a piezoelectric diaphragm, it is preferably lower than the acoustic impedance value of the intermediate diaphragm 5.

  Next, an ultrasonic generator according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a perspective view showing an appearance of the ultrasonic generator according to the second embodiment, and FIG. 6 is a front sectional view thereof.

  The ultrasonic generator 21 has a substantially disc-shaped vibrating body 22. As shown in FIG. 6, the vibrating body 22 includes a first plate-like body 23, a second plate-like body 24, and an intermediate diaphragm 25. As shown in the partially cutaway cross-sectional perspective view in FIG. 7, in the vibrating body 22, the first plate-like body 23 and the second plate-like body 24 have a disk shape. The intermediate diaphragm 25 also has a disk shape.

  In this embodiment, the outer peripheral edge of the first plate-like body 23, the outer peripheral edge of the second plate-like body 24, and the outer peripheral edge of the intermediate diaphragm 25 are formed by the cylindrical outer peripheral side wall portion 26. Are connected. Thereby, a substantially disc-shaped vibrating body 22 is configured.

  Also in the present embodiment, the first space 27a and the second space 27b are closed. Therefore, it is excellent in drip-proof property.

  In the present embodiment, the outer peripheral side wall portion 26 has a cylindrical shape in order to constitute the disk-shaped vibrating body 22.

  Also in this embodiment, the driving member is the intermediate diaphragm 25. That is, the intermediate diaphragm 25 includes a disk-shaped piezoelectric body 30, a first electrode 31, a second electrode 32, and an intermediate electrode 32a. The disk-shaped piezoelectric body 30 is made of piezoelectric ceramic and is polarized in the thickness direction. As shown in FIG. 6, a first electrode 31 is formed on the upper surface of the disk-shaped piezoelectric body 30. A second electrode 32 is formed on the lower surface of the piezoelectric body 30. An intermediate electrode 32 a is formed inside the piezoelectric body 30. The first and second electrodes 31, 32 and the intermediate electrode 32a also have a disk shape. As shown in FIG. 8, the first electrode 31 has a circular shape with a smaller diameter than the disk-shaped piezoelectric body 30. The second electrode 32 and the intermediate electrode 32 a are shaped to overlap the first electrode 31.

  Moreover, in this embodiment, as shown in FIG.5 and FIG.6, the end of the 1st, 2nd support members 33 and 34 is connected to the position where the outer peripheral side wall part 26 opposes. A portion of the outer peripheral side wall portion 26 to which the intermediate diaphragm 25 is connected becomes a vibration node. One end of each of the first and second support members 33 and 34 is connected to a position serving as a vibration node on the outer surface of the outer peripheral side wall portion 26. The other ends of the first and second support members 33 and 34 are connected to a frame-shaped holding member 35.

  The first and second support members 33 and 34 and the frame-shaped holding member 35 can be made of appropriate insulating ceramics. Preferably, the first and second plate-like bodies 23 and 24 are made of the same ceramic material. In that case, the types of materials can be reduced and the manufacturing process can be simplified.

  Also in this embodiment, the frame-shaped holding member 35 is disposed so as to surround the space in which the vibrating body 22 is provided. The vertical dimension of the frame-shaped holding member 35 is larger than the vertical dimension of the vibrating body 22. Therefore, the vibrating body 22 can be reliably protected from the outside. Further, the frame-shaped holding member 35 can be easily fixed to the housing of the electronic device.

  Also in this embodiment, the intermediate diaphragm 25 is a driving member, and the first and second plate-like bodies 23 and 24 are non-driving members. When the intermediate diaphragm 25 vibrates in the bending mode, the first and second plate-like bodies 23 and 24 resonate with the intermediate diaphragm 25 in an antisymmetric manner along with the vibration of the intermediate diaphragm 25. That is, as in the first embodiment, when an alternating electric field is applied, the vibrating body 22 vibrates so that the vibration state shown in FIG. 4A and the vibration state shown in FIG. . Further, when the first plate-like body 23 is disposed on the ultrasonic wave emission side, the first plate-like body 23 can be made of a material having an acoustic impedance value close to the acoustic impedance value of air. As a result, a decrease in output efficiency can be suppressed. In addition, about the 2nd plate-shaped body 24, you may form with the same material as the 1st plate-shaped body 23, and may form with another material. The intermediate diaphragm 25 can be made of the same material as that of the first embodiment.

  Like the ultrasonic generator 21 of the second embodiment, the vibrating body 22 is made of a disk-like first and second plate-like bodies 23 and 24 and a disk-like intermediate diaphragm 25 and a cylindrical shape. You may comprise by the outer peripheral side wall part 26. FIG. In this case, the vibration efficiency can be further effectively increased by the shape.

  Further, since the vibrating body 22 does not have directionality in the outer peripheral side wall portion 26, the pair of support members 33 and 34 may be joined to arbitrary facing positions of the outer peripheral side wall portion 26. Therefore, the assembly process can be simplified. Instead of the pair of support members 33 and 34, a plurality of support members may be uniformly arranged in other forms in the circumferential direction of the frame-shaped holding member 35 in the circumferential direction of the outer peripheral side wall portion 26.

  The frame-shaped holding member 35 has a rectangular frame shape, but may have an annular shape. That is, the planar shape of the vibrating body 22 and the planar shape of the frame-shaped holding member 35 may be appropriately modified.

  FIG. 9 is a front sectional view showing an essential part of an ultrasonic generator according to the third embodiment of the present invention. FIG. 9 illustrates only the vibrating body 41 used in the third embodiment. The vibrating body 41 includes a first plate-like body 42, a second plate-like body 43, an intermediate diaphragm 44, and an outer peripheral side wall portion 45. The first plate-like body 42, the intermediate diaphragm 44 and the outer peripheral side wall 45 are configured in the same manner as the first plate-like body 23, the intermediate diaphragm 25 and the outer peripheral side wall 26 of the vibrator 22 of the second embodiment. Has been. The difference is that the second plate-like body 43 is a drive member that vibrates actively, that is, a piezoelectric diaphragm. In the present embodiment, the second plate-shaped body 43 includes a disk-shaped piezoelectric body 46, an electrode 47 formed on the upper surface of the piezoelectric body 46, an electrode 48 formed on the lower surface, and an intermediate electrode 48a. . The piezoelectric body 46 is polarized in the same thickness direction as the intermediate diaphragm 44.

  Accordingly, the second plate-like body 43 is also actively driven by applying an AC electric field in the same manner as the intermediate diaphragm 44. In this case, the second plate-like body 43 is driven so that the vibration of the second plate-like body 43 has an antisymmetric shape with the vibration of the intermediate diaphragm 44.

  Therefore, when the intermediate diaphragm 44 is displaced in the arrow Z direction in FIG. 9, the second plate 43 is displaced in the −Z direction together with the first plate 42.

  In the present embodiment, the second plate-like body 43 is also actively driven. Therefore, the output efficiency of ultrasonic waves can be further increased. Moreover, the first plate-like body 42 can be formed using a material having an acoustic impedance value close to the acoustic impedance value of air. This can also increase the output efficiency.

  The third embodiment is the same as the second embodiment except that the vibrating body 41 is used. Therefore, the support member and the frame-shaped holding member shown in the second embodiment can be similarly connected. Therefore, parts other than the vibrating body 41 are omitted by using the description of the second embodiment.

  FIG. 10 is a cross-sectional view showing a vibrating body 51 of an ultrasonic generator according to the fourth embodiment. The vibrating body 51 includes a first plate-like body 52, a second plate-like body 53, an intermediate diaphragm 54, and an outer peripheral side wall portion 55. In the present embodiment, the first plate-like body 52 is a piezoelectric diaphragm that actively vibrates. The first plate-like body 52 includes a piezoelectric body 56, an electrode 57 provided on the upper surface of the piezoelectric body 56, an electrode 58 provided on the lower surface, and an intermediate electrode 58a. The first plate-like body 52 is driven so as to be displaced in the opposite direction to the intermediate diaphragm 54.

  In other structures, the vibrating body 51 is configured in the same manner as the vibrating body 41. That is, the second plate-like body 53 includes the piezoelectric body 46 and the electrodes 47 and 48. In the present embodiment, all of the first and second plate-like bodies 52 and 53 and the intermediate diaphragm 54 are drive members made of piezoelectric diaphragms. Therefore, the output efficiency can be effectively increased. The first and second plate-like bodies 52 and 53 and the intermediate diaphragm 54 are all polarized in the same thickness direction. Also in this embodiment, when the intermediate diaphragm 54 is displaced in the arrow Z direction in FIG. 10, the first and second plate-like bodies 52 and 53 are driven so as to be displaced in the −Z direction. That is, the first and second plate-like bodies 52 and 53 are driven in a phase opposite to that of the intermediate diaphragm 54. Therefore, as in the first and second embodiments, the first and second plate-like bodies 52 and 53 vibrate in an antisymmetric vibration mode with respect to the vibration of the intermediate diaphragm 54.

  In the present embodiment, since the first and second plate-like bodies 52 and 53 are also driven, the output efficiency can be further improved.

  The fourth embodiment is the same as the second embodiment except that the vibrating body 51 is used. Therefore, about a support member, a frame-shaped holding member, etc., it abbreviate | omits by using description of 2nd Embodiment.

  Even in the vibrating bodies 41 and 51 of the third and fourth embodiments, even if the support member is connected to the outer surface of the portion of the outer peripheral side wall portions 45 and 55 to which the intermediate diaphragms 44 and 54 are connected. The frequency fluctuation of the ultrasonic wave hardly occurs. Therefore, it is possible to increase the output efficiency as in the first and second embodiments.

  The piezoelectric diaphragm was a unimorph vibrator in the first embodiment, and a bimorph vibrator in the second and third embodiments. However, the piezoelectric diaphragm is a known bimorph vibrator or a laminated power generator having three or more layers. A piezoelectric diaphragm may be configured by the above.

  Moreover, in each embodiment mentioned above, although a piezoelectric material consists of lead zirconate titanate ceramics (PZT), it is not restricted to this. For example, it may be made of a non-lead piezoelectric ceramic material such as potassium sodium niobate and alkali niobate ceramics.

  Further, as is apparent from the comparison between the first embodiment and the second embodiment, the planar shapes of the first and second plate-like bodies and the intermediate diaphragm are not particularly limited. However, it is desirable to have an isotropic shape as in the second embodiment. Therefore, a circle, a square, a regular polygon other than a square, and the like are desirable.

  Further, the support member is not essential in the present invention. That is, in the present invention, each vibrator described in the first to fourth embodiments is an essential configuration. The portion where the intermediate diaphragm on the outer peripheral side wall of the vibrating body is connected constitutes a vibration node. Therefore, if such a vibrating body is used, it is possible to provide an ultrasonic generator with high output efficiency by connecting a support member or another member to a position that becomes a node of the vibration and hardly causing frequency fluctuation. .

  In addition, when providing a supporting member, the number is not specifically limited, However, As shown in 2nd Embodiment, it is desirable to provide a some supporting member uniformly along the outer periphery of a vibrating body.

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic generator 2 ... Vibrating bodies 3, 4 ... 1st, 2nd plate-shaped body 5 ... Intermediate diaphragm 6, 7 ... 1st, 2nd space 8, 9 ... 1st, 2nd outer periphery Side wall portion 10 ... piezoelectric body 11 ... metal plate 11a ... portion 12 also serving as support member ... lead terminal 13 ... electrode 13a ... conducting portion 15 ... lead terminal 17 ... frame-like holding member 18 ... space 21 ... ultrasonic generator 22 ... Vibrating bodies 23, 24 ... First and second plate-like bodies 25 ... Intermediate diaphragm 26 ... Outer peripheral side wall portions 27a, 27b ... First and second spaces 30 ... Piezoelectric bodies 31, 32 ... First and second Electrodes 32a ... intermediate electrodes 33, 34 ... support members 35 ... frame-like holding members 41 ... vibrating bodies 42, 43 ... first and second plate-like bodies 44 ... intermediate diaphragm 45 ... outer peripheral side wall 46 ... piezoelectric body 47 48 ... Electrode 48a ... Intermediate electrode 51 ... Vibrating bodies 52, 53 ... First and second plate-like bodies 54 ... Intermediate diaphragm 55 Peripheral side wall portion 56 ... piezoelectric 57,58 ... electrode 58a ... intermediate electrode

Claims (9)

A first plate-like body;
Between the first plate-like body and the second plate-like body, the second plate-like body disposed so as to be opposed to the first plate-like body and the main surfaces, An intermediate diaphragm disposed and opposed to the first and second plate-like bodies;
An outer peripheral side wall connecting each outer peripheral edge of the first plate-like body, the intermediate diaphragm and the second plate-like body,
The intermediate diaphragm is a piezoelectric diaphragm that vibrates in a bending mode, and the first and second plate-like bodies vibrate in antisymmetric resonance with respect to the vibration of the intermediate diaphragm. a diaphragm, the first and second plate member are connected by the peripheral side wall,
The ultrasonic generator , wherein a portion of the outer peripheral side wall connected to the intermediate diaphragm is a vibration node .   The ultrasonic generator according to claim 1, wherein the first plate-like body is a non-driving member that vibrates with the vibration of the intermediate diaphragm.   The ultrasonic generator according to claim 2, wherein an acoustic impedance of the first plate-like body is lower than an acoustic impedance of the intermediate diaphragm.   The ultrasonic generator according to claim 1, wherein the second plate-like body is a drive member that actively vibrates.   The ultrasonic generator according to claim 1 or 3, wherein the first and second plate-like bodies are drive members that actively vibrate.   The outer peripheral side wall includes a first space between the first plate-like body and the intermediate diaphragm, and a second space between the intermediate diaphragm and the second plate-like body. The whole of the outer peripheral edges of the first plate, the intermediate diaphragm, and the second plate are connected to each other so as to be closed. Ultrasonic generator. The ultrasonic generator according to any one of claims 1 to 6 , further comprising a support member connected to an outer surface of a portion of the outer peripheral side wall connected to the intermediate diaphragm. The ultrasonic generator according to claim 7 , further comprising a holding member connected to the support member. The holding member is a frame-like holding member is provided so as to surround the structure having the first and second plate-like body and said intermediate diaphragm and the peripheral side wall, according to claim 8 Ultrasonic generator.

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