JP5541022B2 - Vibration device - Google Patents

Description

  The present invention relates to a vibration device having a structure in which, for example, a diaphragm made of a piezoelectric diaphragm is attached to a frame-like support via a support sheet, and more specifically, the shape of the opening of the support is many. The present invention relates to a vibration device having a square shape.

  2. Description of the Related Art Conventionally, piezoelectric sounders, piezoelectric speakers, and the like are used in mobile phones and various electronic devices to generate sound and vibration.

  For example, Patent Literature 1 below discloses a piezoelectric acoustic component shown in an exploded perspective view in FIG. In the piezoelectric acoustic component 101, a metal plate 103 drawn into a cap shape is fixed on a substrate 102.

  On the upper surface of the metal plate 103, a plurality of slits 103a are arranged in a rectangular frame shape. The piezoelectric diaphragm 104 is joined to the upper surface of the metal plate 103 at a portion surrounded by the plurality of slits 103a. A portion between adjacent slits 103 a and 103 a, that is, a portion where no slit is formed, is located in the vicinity of a corner portion of the rectangular piezoelectric diaphragm 104. Along with the vibration of the piezoelectric diaphragm 104, the metal plate portion surrounded by the plurality of slits 103a is greatly displaced. Therefore, a large sound can be obtained.

  On the other hand, the following Patent Document 2 discloses a piezoelectric speaker shown in FIGS. 11 (a) and 11 (b). In the piezoelectric speaker 111, the piezoelectric element 112 is bonded to the upper surface of the diaphragm 113 made of metal. The diaphragm 113 is affixed on a resin plate 114 as a damper member. The resin plate 114 is fixed to the supports 115 and 116 at a pair of opposing side portions of the resin plate 114. That is, the resin plate 114 having a damping property is supported by the supports 115 and 116 so as not to hinder the vibration of the piezoelectric element 112 and the diaphragm 113.

Japanese Patent Laid-Open No. 11-355892 Japanese Patent Laid-Open No. 9-271096

  In the piezoelectric acoustic component 101 described in Patent Document 1, since the plurality of slits 103a are formed in the metal plate 103, displacement due to the piezoelectric effect can be increased and a large sound pressure can be obtained. However, the cap-shaped metal plate 103 had to be prepared by drawing. In addition, the slit 103a must be filled with a sealing material in order to separate the air chambers. Accordingly, there are problems that the machining process is complicated and the number of parts increases.

On the other hand, in the piezoelectric speaker 111 described in Patent Document 2, a pair of long side portions of the resin plate 114 are supported by the supports 115 and 116, but the resin plate 114 is supported on the pair of short sides. Absent. Therefore, on the pair of short sides of the resin plate 114, it is necessary to increase the support strength using a sealing material. As a result, the number of parts increases, and the machining process becomes complicated. In addition, since the resin plate 114 is firmly supported on the pair of long sides, the displacement tends to be suppressed on the pair of long sides. Therefore, there is a possibility that the displacement of the vibrating body including the piezoelectric element 112 and the diaphragm 113 may be reduced.

  An object of the present invention is to solve the above-mentioned disadvantages of the prior art, to prevent displacement of the vibrating body from being suppressed, to obtain a large displacement amount, and to provide without increasing the number of parts and the number of processing steps. An object of the present invention is to provide a vibration device capable of performing

The vibration device according to the present invention includes a diaphragm, a diaphragm laminated on the diaphragm, a diaphragm laminated portion affixed to the diaphragm, and an extension projecting outside the diaphragm laminated portion. And a frame-like support body that is affixed to an extension of the support sheet and that is spaced from the outer peripheral edge of the diaphragm. The support sheet is made of a synthetic resin film. In the present invention, the frame-shaped support has a plurality of sides and a polygonal opening in which a portion where adjacent sides are connected is a corner, and the support of the support sheet than the elastic modulus of the synthetic resin film portion is attached to the central portion of the side of the opening, the said support elastic modulus of the synthetic resin film portion is attached to the corner portion of the opening portion of the support sheet It is high.

  In a specific aspect of the vibration device according to the present invention, from a portion of the support sheet that is affixed to a central portion of the side of the opening of the support, a corner portion of the opening of the support of the support sheet The elastic modulus of the support sheet is increased as it goes to the portion attached to the sheet.

  In another aspect of the vibration device according to the present invention, the opening of the frame-shaped support is rectangular.

  In the present invention, the planar shape of the diaphragm is not particularly limited, but in still another specific aspect of the present invention, the diaphragm is a rectangular plate.

  In still another specific aspect of the vibration device according to the present invention, the diaphragm is a piezoelectric vibrator.

  In still another specific aspect of the vibration device according to the invention, the piezoelectric vibrator includes a metal plate and a piezoelectric element bonded to one surface of the metal plate.

  In the vibration device according to the present invention, the support sheet is affixed to the frame-shaped support, but the support sheet is supported more than the elastic modulus of the support sheet part that is affixed to the center of the side of the opening of the support. Since the elastic modulus of the support sheet portion attached to the corner portion of the opening of the body is increased, the amount of displacement of the entire diaphragm can be increased. Therefore, a large sound pressure and a large vibration can be obtained. Moreover, since the vibration device of the present invention only has a support structure in which the support sheet is attached to the frame-shaped support, the number of parts does not increase. Moreover, the complexity of the processing steps can be avoided. Therefore, a vibration device with a large displacement can be provided at low cost.

(A) And (b) is a top view of the vibration device which concerns on one Embodiment of this invention, and sectional drawing of the part in alignment with the BB line in (a), (c) is used. It is front sectional drawing of a piezoelectric element. (A) And (b) is the typical top view and typical bottom view for demonstrating the elastic modulus distribution of the support film in the vibration apparatus of one Embodiment of this invention, (c) is (b) It is sectional drawing of the part which follows the CC line in it. It is a typical perspective view which shows the displacement distribution of the vibration apparatus prepared for the comparison. It is a typical perspective view for demonstrating the displacement distribution of the vibration apparatus which concerns on one Embodiment of this invention. It is a figure which shows the relationship between the area | region of a support sheet and an elasticity modulus in the vibration apparatus prepared as one Embodiment and comparative example of this invention. It is a typical top view for explaining elastic modulus distribution in a vibration device of one embodiment of the present invention. (A) And (b) is the typical top view and typical bottom view for demonstrating distribution of the elasticity modulus of the support sheet in the vibration apparatus of other embodiment of this invention. (A) And (b) is the top view and bottom view of the vibration apparatus which concern on other embodiment of this invention. It is front sectional drawing for demonstrating the further another example of the diaphragm used with the vibration apparatus of this invention. It is a disassembled perspective view of the conventional piezoelectric electroacoustic transducer. (A) And (b) is a perspective view which shows an example of the conventional piezoelectric speaker, and sectional drawing of the part in alignment with the BB line in (a).

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

  Fig.1 (a) is a top view which shows the vibration apparatus which concerns on one Embodiment of this invention, (b) is sectional drawing of the part in alignment with the BB line in (a).

  The vibration device 1 according to the present embodiment includes a vibration plate 2, a support sheet 3 attached to the vibration plate 2, and a frame-like support body 4 disposed so as to surround the support sheet 3.

  The diaphragm 2 has a rectangular plate shape. In FIG. 1B, a part of the diaphragm 2 is schematically shown, but in actuality, the diaphragm 2 is formed on both surfaces of the multilayer piezoelectric body 2a and the multilayer piezoelectric body 2a. It has electrodes 2b and 2c. The multilayer piezoelectric body 2a is made of PZT having two or more piezoelectric layers.

  The upper and lower piezoelectric layers are polarized in the thickness direction so as to expand and contract in reverse when an electric field is applied. Therefore, the diaphragm 2 is excited in the bending vibration mode by applying an alternating electric field from the electrodes 2b and 2c. That is, the diaphragm 2 is a piezoelectric vibrator in the present embodiment. The diaphragm may be attached to both sides of the support sheet.

  The structure of the piezoelectric vibrator is not limited to that using the multilayer piezoelectric body 2a shown in FIG. For example, a unimorph type piezoelectric vibrator in which a piezoelectric layer 2e and an electrode 2f polarized in the thickness direction are stacked on a metal plate 2d, such as a diaphragm 2A shown in FIG. Furthermore, in the present invention, the diaphragm 2 may be a vibrating body other than the piezoelectric vibrator.

  As shown in FIGS. 1A and 1B, the diaphragm 2 is attached to the upper surface of the support sheet 3. This affixing can be performed using an appropriate bonding material such as an adhesive. Although the support sheet 3 is not specifically limited, in this embodiment, it consists of a synthetic resin film. The support sheet 3 is not limited to a synthetic resin film, and may be formed of a metal plate.

The support sheet 3 is connected to the diaphragm laminated portion 3A to which the rectangular plate-like diaphragm 2 is attached, and the diaphragm laminated portion 3A, and has a rectangular frame shape leading to the outside of the diaphragm laminated portion 3A. And an extension 3B. An outer portion of the rectangular frame-shaped extension 3B is fixed by a frame-shaped support body 4.

  In this embodiment, the frame-shaped support body 4 has a rectangular frame-shaped planar shape. That is, the frame-shaped support body 4 has a rectangular opening. The rectangular opening has a pair of long sides 4a and 4b facing each other and a pair of short sides 4c and 4d facing each other. Adjacent sides, that is, a part where the sides 4a and 4c are connected is defined as a first corner portion 4e. Further, the portion where the side 4b and the side 4c are connected is connected to the second corner portion 4f, the portion where the side 4a and the side 4d are connected is connected to the third corner portion 4g, and the side 4d and the side 4b are connected. The portion that is present is the fourth corner portion 4h.

  The frame-shaped support 4 has metal plates 4i and 4j. The metal plates 4i and 4j are bonded together so as to sandwich the support sheet 3. This bonding can be performed using an appropriate bonding material such as an adhesive.

  In addition, the frame-shaped support body 4 can be formed with other rigid materials, such as not only a metal but ceramics and a synthetic resin.

  In the present embodiment, the metal plate 4i and the metal plate 4j have the same planar shape, but may have different planar shapes. For example, the metal plate 4j may protrude outward from the metal plate 4i, and electrical connection or the like may be performed at the protruding portion.

  In the vibration device 1 according to the present embodiment, when the vibration plate 2 made of the piezoelectric vibrator is excited in the bending mode, the vibration plate 2 is supported by a flexible support sheet 3. Is not so hindered. In particular, the feature of the present embodiment is that the elastic modulus of the support sheet 3 is partially different, whereby a large amount of displacement can be obtained. This will be described more specifically with reference to FIGS.

  In the vibration device 1 of the present embodiment, the support sheet 3 has an elastic modulus distribution. FIG. 2A is a plan view of the vibration device 1 schematically showing the elastic modulus distribution in the support sheet 3. FIG. 2B is a bottom view of the vibration device 1, and in FIG. 2B, the elastic modulus distribution of the support sheet 3 is schematically shown. That is, the support sheet 3 has a region 3a having the highest elastic modulus in the vicinity of the first to fourth corner portions 4e to 4h of the frame-shaped support 4 described above, and the elastic modulus increases as the distance from the region 3a increases. Has regions 3b, 3c, 3d, and 3e that are sequentially lowered.

  Therefore, in the part affixed on the frame-shaped support body 4 of the support sheet 3, the frame shape of the support sheet 3 is more than the elastic modulus of the support sheet part affixed to the center part of edge | side 4a-4d. The elastic modulus of the part pasted on the corners 4e to 4h of the opening of the support body 4, that is, the region 3a is increased. Moreover, in this embodiment, the elasticity modulus of the support sheet 3 is as it goes to the support sheet part currently affixed on the corner parts 4e-4h from the support sheet part affixed on the center part of edge | side 4a-4d. It is continuously high.

  Further, as shown in FIG. 2 (c), the elastic modulus of the support sheet 3 also extends from the region 3e in the portion from the center portion of the support sheet 3 toward the first corner portion 4e in the diagonal direction of the support sheet 3. The elastic modulus is increased in the order of the region 3d, the region 3c, the region 3b, and the region 3a.

  In the vibration device 1 of the present embodiment, since the support sheet 3 has the above elastic modulus distribution, a large amount of displacement can be obtained. This will be described based on a specific experimental example.

  In this experimental example, the diaphragm 2 is made of PZT, and a stacked piezoelectric body having six piezoelectric layers of 16 mm length × 12 mm transverse wave × 100 μm thickness is used. The upper and lower electrodes 2b and 2c are made of Ag / Pd and have a thickness of 1 μm.

  The frame-like support 4 was formed by laminating metal plates 4i and 4j having a thickness of 0.2 mm.

  The opening of the frame-shaped support 4 was a rectangular opening with sides 4a and 4b having a length of 17 mm.

  As the support sheet 3, a synthetic resin film made of rubber or plastic having a thickness of 100 μm was used. However, a synthetic resin film having a structure in which the elastic modulus is changed as indicated by the solid line in FIG. Such a synthetic resin film having partially different elastic moduli is a method in which the content of the additive in the synthetic resin film is different in the regions 3a to 3e, or the cross-linking degree of the synthetic resin film is different in the regions 3a to 3e. It can be obtained by a method or the like.

  For comparison, in place of the support sheet 3, a comparative example was used in the same manner as in the above embodiment except that a support sheet having a constant elastic modulus in all regions as shown by the broken line in FIG. 5 was used. A vibration device was prepared.

FIG. 3 is a perspective view schematically showing a displacement shape by a finite element method when a voltage of 8 V is applied to the vibration device of the comparative example. FIG. 4 is a schematic perspective view showing a displacement shape by a finite element simulation of a vibration device prepared as an experimental example of the embodiment. 3 and 4 show the displacement shape. That is, the support sheet 3 vibrates together with the diaphragm 2 but is restrained by the frame-shaped support body 4. Therefore, the displacement shape shown in FIGS. 3 and 4 is the frame-like support 4.
The displacement shape of the structure which consists of the diaphragm 2 and the support sheet 3 in the opening part of this is shown.

  The numerical values in the z direction in FIGS. 3 and 4 indicate the standardized displacement amount at the portion where the support sheet 3 is attached to the sides 4 a and 4 d of the opening of the frame-like support 4. Numerical values in the x and y directions indicate position coordinates.

  As is clear from the comparison between FIG. 3 and FIG. 4, it can be seen that a larger displacement amount can be obtained according to the embodiment than in the comparative example. That is, it can be seen that the corner portion surrounded by the circle X shown by the broken line in FIG. 3 is relatively greatly displaced in the minus direction. On the other hand, as shown in FIG. 4, in the above embodiment, it can be seen that the displacement in the minus direction in the portion surrounded by the circle Y indicated by the broken line, that is, the corner portion, is very small.

  In the corner portions 4e to 4h in FIG. 6, that is, the portion surrounded by a circle Y indicated by a broken line, the displacement is very small, and the displacement in the minus direction is particularly small. On the other hand, the amount of displacement is large at the center of the sides 4a to 4d surrounded by the circle Z. This is because the support sheet 3 having the elastic modulus distribution is used. Therefore, in the vibration device 1 of the present embodiment, the displacement amount of the structure in which the diaphragm 2 is joined to the support sheet 3 can be greatly increased, and a large sound pressure can be obtained.

  As described above, a large amount of displacement can be obtained in this embodiment simply by giving the elastic modulus distribution to the support sheet 3. Therefore, it is possible to provide a vibration device that can obtain a large sound pressure without causing an increase in the number of parts and a complicated assembly process.

FIGS. 7A and 7B are a schematic plan view and a schematic bottom view for explaining the vibration device according to the second embodiment of the present invention.

  7A and 7B, the elastic modulus distribution of the support sheet 3 is schematically shown as in FIGS. 2A and 2B. That is, the elastic moduli of the regions 3a to 3e are different as in the first embodiment. The second embodiment is different from the first embodiment in that the planar shape of the frame-like support 4B is different, and the other points are the same as in the first embodiment.

  The opening of the frame-shaped support body 4B has a substantially rectangular shape. That is, the opening swells outward at the center of the sides 4a to 4d. Therefore, the distance between the diaphragm 2 and the frame-like support 4 is relatively larger than the corner portions 4e to 4h at the centers of the sides 4a to 4d. In other words, the distance between the diaphragm 2 and the frame-shaped support body 4 is reduced from the center of the sides 4a to 4d toward the corners 4e to 4h.

  As described above, the distance between the diaphragm 2 and the frame-like support 4 is made smaller on the corners 4e to 4h side than the center of the sides 4a to 4d, so that the support sheet 3 is displaced at the corners. It can be made smaller. Moreover, the displacement at the center side of the sides 4a to 4d can be further increased, and thereby the displacement amount of the structure in which the diaphragm 2 is joined to the support sheet 3 can be effectively increased. Thus, not only the elastic modulus distribution is given to the support sheet 3 but also the displacement amount can be further increased by adjusting the distance between the frame-like support 4 and the diaphragm 2.

  FIGS. 8A and 8B are a schematic plan view and a schematic bottom view for explaining a vibration device according to a third embodiment of the present invention. In the present embodiment, a support sheet 13 is used. Except for using the support sheet 13 instead of the support sheet 3, the third embodiment is configured in the same manner as the first embodiment.

  The support sheet 13 has a sheet body 13a. For example, the sheet body 13a made of rubber or plastic is a normal synthetic resin film having a uniform elastic modulus over the entire region. In the support sheet 13, high elastic modulus layers 13b are partially laminated on both surfaces of the sheet body 13a. The high elastic modulus layer 13b is laminated in the vicinity of the corner portions 4e to 4h of the frame-like support 4 described above.

  The high elastic modulus layer 13b is made of a material having a higher elastic modulus than the sheet main body 13a. Such a material is not particularly limited as long as the elastic modulus is higher than that of the sheet main body 13a. For example, the high elastic modulus layer 13b may be formed of a composition obtained by adding an additive that further increases the elastic modulus to the synthetic resin constituting the sheet main body 13a. Or you may form the high elastic modulus layer 13b with the resin material different from the sheet | seat main body 13a.

  The high elastic modulus layer 13b may be made of a material other than resin.

  In the third embodiment, since the high elastic modulus layer 13b exists in the corner portions 4e to 4h, the elasticity of the support sheet portion attached to the center of the sides 4a to 4d is the same as in the first embodiment. Compared with the rate, the elastic modulus of the portion of the support sheet attached to the frame-like support 4 in the corner portions 4e to 4h is relatively high. Therefore, a large amount of displacement can be obtained as in the first embodiment.

In the first to third embodiments described above, the opening portion of the frame-shaped support body 4 has a rectangular planar shape, but has other polygonal shapes such as a pentagon and a hexagon other than a rectangle. You may do it. In any case, the elastic modulus of the support sheet portion attached to the corner portion of the polygon is set higher than the elastic modulus of the support sheet portion attached to the center of the plurality of sides in the polygon. For example, a large displacement amount can be obtained as in the above embodiment.

  Moreover, in 1st Embodiment, as it goes to the support sheet part currently affixed on the corner parts 4e-4h from the part affixed on the center part of edge | side 4a-4d of the frame-shaped support body 4, Although the elastic modulus of the support sheet 3 was continuously increased, the change in the elastic modulus may be stepped as in the third embodiment.

  In the first to third embodiments, the diaphragm 2 has a rectangular plate shape, but may have a planar shape other than the rectangular plate shape, for example, a circular shape.

DESCRIPTION OF SYMBOLS 1 ... Vibration apparatus 2 ... Vibration plate 2A ... Vibration plate 2a ... Laminated piezoelectric body 2b, 2c ... Electrode 2d ... Metal plate 2e ... Piezoelectric layer 2f ... Electrode 3 ... Support sheet 3A ... Vibration plate laminated part 3B ... Extension part 3a -3e ... region 4 ... support 4B ... support 4a-4d ... side 4e ... first corner 4f ... second corner 4g ... third corner 4h ... fourth corner 4i, 4j ... metal Plate 13 ... Support sheet 13a ... Sheet body 13b ... High elastic modulus layer

Claims (6)

A diaphragm,
A support sheet that is affixed to the diaphragm, and that has a diaphragm laminated part that is affixed to the diaphragm, and an extension that projects to the outside of the diaphragm laminated part,
A frame-like support body that is affixed to the extension portion of the support sheet and that is provided at an interval from the outer periphery of the diaphragm;
The support sheet is made of a synthetic resin film,
The frame-shaped support has a plurality of sides and a polygonal opening in which a portion where adjacent sides are connected is a corner, and the sides of the opening of the support of the support sheet than the elastic modulus of the synthetic resin film portion is attached to the central portion of the elastic modulus of the support adhered to the corner portion with its dependent synthetic resin film portion of the opening portion of the support sheet is high , Vibration device.   The support sheet as it goes from the portion of the support sheet attached to the center of the side of the opening of the support to the portion of the support sheet attached to the corner of the opening of the support. The vibration device according to claim 1, wherein the elastic modulus of the vibration device is high.   The vibration device according to claim 1 or 2, wherein the opening of the frame-shaped support is rectangular.   The vibration device according to claim 1, wherein the vibration plate has a rectangular plate shape.   The vibration device according to claim 1, wherein the vibration plate is a piezoelectric vibrator.   The vibration device according to claim 5, wherein the piezoelectric vibrator includes a metal plate and a piezoelectric element bonded to one surface of the metal plate.

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