JP2004221903A - Piezoelectric sounding element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the acoustic characteristic of a piezoelectric sounding element and to miniaturize the piezoelectric sounding element. <P>SOLUTION: The piezoelectric sounding element has a vibrator 36 having at least a piezoelectric diaphragm 34 consisting of piezoelectric elements 33 (3A, 33B) and a diaphragm 32 to which the piezoelectric elements 33 are stuck. The vibrator 36 is joined to a fixing part 26 through a member 37 deforming following the vibration of the vibrator 36. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a piezoelectric sounding element incorporated in various electronic devices and a method for manufacturing the same.
[0002]
[Prior art]
With the advancement of miniaturization and high performance of electronic devices and advancement of communication technology, the size and thickness of the sound generating element itself have been reduced. Piezoelectric sound elements have a simple structure in principle and are particularly suitable for thinning, and are widely used in various electronic devices. A typical example of the piezoelectric sounding element is a piezoelectric buzzer. 14A and 14B show an example of a piezoelectric buzzer. The piezoelectric buzzer 1 is provided with a piezoelectric vibrating plate 4 formed by bonding a circular piezoelectric element 2 and a vibrating plate 3 made of a thin metal plate, and an outer peripheral portion of the piezoelectric vibrating plate 4 is formed on a housing 5 of the device. The sound is generated by applying a signal voltage 7 to both surfaces of the piezoelectric element 2, that is, between the metal diaphragm 3 and the electrodes on the surface of the piezoelectric element 2.
[0003]
Conventionally, a piezoelectric sounding element has a remarkably large variation in generated sound pressure depending on the frequency, and it is difficult to produce high-quality sound, and is limited to applications such as electronic sound (buzzer sound). On the other hand, small speakers with high sound quality using piezoelectric elements have been studied.
Patent Literature 1, Patent Literature 2, Patent Literature 3, and Patent Literature 4 describe piezoelectric speakers using a piezoelectric element.
[0004]
[Patent Document 1]
JP-A-7-226999
[Patent Document 2]
JP-A-2002-199493
[Patent Document 3]
Patent No. 2551813
[Patent Document 4]
Japanese Patent Application No. 11-164396
[0005]
[Problems to be solved by the invention]
The piezoelectric sounding element is suitable for thinning, but requires a certain area in order to secure necessary sound pressure and sound quality. FIG. 13 shows a cross-sectional structure of a basic piezoelectric sounding element. The piezoelectric sounding element 11 includes a piezoelectric vibration plate 14 in which a piezoelectric element 13 is attached to one surface of a metal vibration plate 12. The peripheral end of the vibration plate 12 of the piezoelectric sounding element 11 is joined to a projecting support 17 formed on a housing 16 having an opening 15 of the device.
[0006]
The outer dimension P of the piezoelectric element 13 and the outer dimension S of the vibration region have a relationship of P <S, and it is desirable that both S and P be large. On the other hand, the actual outer dimension H of the piezoelectric sounding element 11 is a dimension obtained by adding twice the fixed width K 1 for fixing the piezoelectric sounding element 11 to the housing 14 or the like. That is, the actual outer dimension H of the piezoelectric sounding element 11 is H = S + 2 × K. The effective thickness of the piezoelectric sounding element 11 is the gap amount t between the piezoelectric sounding element 11 and the inner surface of the housing 14. ₁ And the thickness t of the piezoelectric sounding element 11 ₂ Thickness T = t ₁ + T ₂ It becomes. Therefore, in order to reduce the size and thickness of the piezoelectric sounding element, it is important to reduce the outer dimensions H and the thickness T.
[0007]
What matters is the outer dimension H of the piezoelectric sounding element 11. In order to ensure sound pressure, it is necessary to increase the outer dimension P of the vibration area, while to reduce the size, it is necessary to reduce the outer dimension H of the piezoelectric sounding element 11. That is, it is desirable to reduce HP = 2 × K, but reducing the fixed width K has a limit because it leads to a reduction in the fixing force. In particular, the piezoelectric sounding element 11 is a vibrating body, and it is very difficult to reduce the fixed width K as much as possible.
[0008]
As described above, in the related art, it is difficult to obtain a structure that achieves both the miniaturization and high sound pressure and high sound quality of the piezoelectric sounding element 11. Further, in order to actually mount the piezoelectric sounding element 11 in the electronic device, it is necessary to bond the piezoelectric sounding element 11 to the housing 14 as described above. Further, even in the case of an element in which a metal or plastic frame is united with the piezoelectric sounding element portion, components such as screwing and double-sided adhesive tape are required for mounting. At the same time, if the mounting state of the piezoelectric sounding element 11 with the mounting device is incomplete, chattering sound may be generated due to vibration of the sounding element, and the piezoelectric sounding element 11 is suitable for thinning, but has a surface that it is difficult to mount.
[0009]
In view of the above, the present invention is compact and has improved acoustic characteristics or can be downsized. An object of the present invention is to provide a piezoelectric sounding element and a method for manufacturing the same.
[0010]
[Means for Solving the Problems]
The piezoelectric sounding element according to the present invention has a vibrating body having at least a piezoelectric vibrating plate including a piezoelectric element and a vibrating plate to which the piezoelectric element is attached, and the vibrating body deforms following the vibration of the vibrating body. It is configured to be joined to the fixed part via a member.
[0011]
According to the piezoelectric sounding element of the present invention, the vibrating body having at least the piezoelectric vibrating plate is joined to the fixed portion via the member that deforms following the vibration of the vibrating body. Following the above deformation, the above member also deforms, and the actual vibration region expands. This makes it possible to bring the vibration region closer to the outer shape of the piezoelectric sounding element.
[0012]
A method of manufacturing a piezoelectric sounding element according to the present invention is a member that forms a vibrating body having at least a piezoelectric vibrating plate in which a piezoelectric element is attached to a vibrating plate, and deforms the outer peripheral portion of the vibrating body by following the vibration of the vibrating body. Is fixed.
[0013]
According to the method for manufacturing a piezoelectric sounding element according to the present invention, a member which is to be joined to the fixed portion and which deforms following the vibration of the vibrating body is fixed to the outer peripheral portion of the vibrating body having at least the piezoelectric vibrating plate. By virtue of this step, the vibration region is enlarged, and it is possible to manufacture a piezoelectric sounding element with improved acoustic characteristics or reduced size.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows the principle of the piezoelectric sounding element according to the present invention. As shown in FIG. 1, the basic principle of the piezoelectric sounding element 21 of the present invention is that an outer periphery of the piezoelectric sounding element 21 having a vibrating body 24 made of a piezoelectric vibrating plate in which a piezoelectric element 23 is attached to a vibrating plate 22. A frame member 25 that deforms following the vibration of the vibrating body 24 is fixed to the portion, and the frame member 24 is directly joined to a fixed portion, for example, a housing 26 having an opening 27 of the device. The frame member 25 has a required thickness and a required elasticity, and is formed of a member having an adhesive surface.
According to the piezoelectric sounding element 21, the actual vibration area of the vibrating body 24 is closer to the outer shape H of the piezoelectric sounding element, not the conventional vibration area outer shape S excluding the fixed width K at both ends. That is, the deformation of the vibrating body 24 also deforms the frame member 25 having an elastic force, so that the actual vibration area can be expanded.
[0015]
FIGS. 2A and 2B show a comparison between the piezoelectric sounding element 11 of FIG. 13 using the conventional support method and the piezoelectric sounding element 21 of the present invention when the piezoelectric diaphragm is deformed. In the conventional structure of FIG. 13, the deformation area of the vibrating body 14 is the distance S between the insides of the support portions 17 as shown in FIG. 2A. On the other hand, in the case of the structure of the present invention shown in FIG. 1, as shown in FIG. 2A, since the elastic frame member 25 is easily deformed, the deformation area of the vibrating body 24 is S ′. According to the present invention, it is possible to make the vibration region S 'closer to the sound-generating element outer shape H, and if the shape is the same as that of the conventional structure, the sound pressure can be improved. Further, according to the present invention, it is possible to reduce the shape to obtain the same sound pressure. Further, the frame member 25 also has a function of fixing to other members, and can be easily fixed to other members without using a means such as an adhesive or a screw. Since the adhesive surface of the frame member 25 is soft, it easily conforms to the unevenness of the mounting surface, and even if a slight gap is generated, almost no chattering noise is generated. Further, the frame member 25 also has a function of absorbing shock, and can improve the shock resistance reliability of the piezoelectric sounding element 21. At the same time, since the frame member 25 absorbs the distortion due to the thermal change, the reliability against the thermal shock and the like can be improved.
[0016]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
Next, an embodiment of the present invention will be described with reference to the drawings. Although the principle of the present invention is as shown in FIG. 1, in the following embodiments, a high-quality piezoelectric speaker is used as an example.
[0018]
3A and 3B show a basic configuration of an embodiment of the piezoelectric sounding element 31 according to the present invention. The piezoelectric sounding element 31 according to the present embodiment is provided with a piezoelectric vibrating plate 34 by bonding two piezoelectric elements 33 [33A, 33B] on both sides of the vibrating plate 32. A vibrating body 36 is formed by covering with a flexible resin sheet 35 [35A, 35B], and a frame member 37 having elasticity is fixed to one surface of an outer peripheral portion of the vibrating body 36. The flexible resin sheet 35 has a larger area than the piezoelectric vibrating plate 34 and has a size substantially equal to the outer shape of the frame member 37. The resin sheet 35 is attached to one of the adhesive surfaces of the frame member 37. Further, the outer shape of the piezoelectric vibrating plate 34 is smaller than the inner size of the frame member 37, and the outer peripheral portion of the piezoelectric vibrating plate 34 has only two flexible resin sheets 35 [35 A, 35 B] ( A so-called flexible part) is formed. As shown in FIG. 3C, the piezoelectric sounding element 31 is configured such that a vibrating body 36 including a piezoelectric element 33 is directly fixed to a fixed portion such as an opening of a device by a frame member 37 having elasticity through a flexible portion including only a resin sheet 35. Is supported by a housing having
[0019]
In the piezoelectric sounding element 31 according to the present embodiment, a vibration generating portion including the piezoelectric element 33, a portion covered on both sides with the flexible resin sheet 35, a portion including only the flexible resin sheet 35, and a frame having elasticity. The structure is such that the rigidity gradually decreases from the vibration generating portion to the support portion of the vibration body 36 to the housing, such as the portion of the member 37, and is configured to flexibly support the vibration region of the vibration body. You.
[0020]
The piezoelectric element 33 [33A, 33B] is generally formed of a piezoelectric material such as a lead zirconate titanate material (usually PZT), and a metallized film of silver, nickel, gold or the like, for example, a conductive paste is formed on both surfaces thereof. An electrode 38 formed of a conductive film is used. When the vibration plate 32 is formed of a thin metal plate, the electrode 38 may be formed on one side of the piezoelectric element 33. In the case of a piezoelectric sounding element, it is desired that the thickness of the piezoelectric element 33 is small, and the piezoelectric element 33 is formed by sheet molding or the like. Although the thickness depends on the element area, a thickness of 100 μm or less is preferably used. Regarding the shape of the piezoelectric element, a circular element 33 as shown in FIGS. ₁ , Square element 33 ₂ , An elliptical element 33 as shown in FIGS. 5A, B and C ₃ , Rectangular element 33 ₄ , An oval element 33 having both ends on an arc connected by a straight line ₅ Etc. can be used. The details of the circle, the ellipse, the rectangle, and the shape as shown in FIGS. 5A, 5B and 5C will be described later.
[0021]
The vibration plate 32 has a function of holding the piezoelectric element 33 [33A, 33B] and taking out an electrode on one side of the piezoelectric element 33, and can be generally made of a metal material. For example, stainless steel, copper, aluminum, Ni alloy, titanium, and the like. Usually, the thickness is usually 100 μm or less. In addition, the diaphragm 32 may be made of a plastic material. In addition, as a method of fixing the piezoelectric element 33 and the vibration plate 32, an epoxy resin adhesive, an anaerobic addition type UV adhesive, or the like can be used.
[0022]
The flexible resin sheet 35 can be a general plastic film, such as a polypropylene film, a polyethylene film, a polyester film, a polyimide film, and other thermoplastic resin films. In this example, depending on the material and thickness of the film, Careful selection is necessary, especially as the sound quality changes. For example, a polyester resin sheet having a thickness of 50 μm can be used.
[0023]
Further, in this example, among the resin sheets 35 covering both surfaces of the piezoelectric vibration plate 34, a polypropylene adhesive sheet can be used for one resin sheet 35A and a thermoplastic resin sheet can be used for the other resin sheet 35B. . In this case, the polypropylene pressure-sensitive adhesive sheet 35A is formed of a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on the surface on the piezoelectric element 33 side, based on a polypropylene resin sheet. Regarding the thickness, the thickness of the base polypropylene resin sheet is, for example, about 20 to 40 μm, and the total thickness including the adhesive layer is, for example, about 60 to 80 μm. As a general-purpose tape, polypropylene has a low mechanical resonance sharpness (Q value) inherent to the material and is suitable for an acoustic material. This polypropylene adhesive sheet 35A is attached to one surface of the piezoelectric vibrating plate 34, thereby improving the acoustic characteristics, insulating the electrode 38, and protecting the piezoelectric element 33.
The thermoplastic resin sheet 35 </ b> B has a thickness of about 50 μm to 100 μm, and is attached to the other surface of the diaphragm 12 by thermocompression. The Young's modulus of the thermoplastic resin sheet 35B itself is small, and it is possible to provide the resin sheet portion with appropriate strength by combining with the above-mentioned polypropylene resin sheet 35A.
[0024]
The frame member 37 desirably has a certain required thickness and elasticity, and needs to have double-sided adhesiveness. For example, a special foamed polyethylene double-sided adhesive tape (No. 5713: thickness 0.33 mm) manufactured by Nitto Denko Corporation is suitable as the frame member 37. In addition, a polyethylene foam material manufactured by Sumitomo 3M is also suitable. When selecting the frame member 37, it is necessary to select the frame member 37 based on the required thickness, heat resistance, and the like.
[0025]
The above-described piezoelectric sounding element 31 can be manufactured as follows.
First, the piezoelectric elements 33A and 33B having the electrodes 38 formed on both surfaces of the vibration plate 32 are attached to form the piezoelectric vibration plate 34. The piezoelectric vibrating plate 34 is covered with a resin sheet 35 [35A, 35B] to form a vibrating body 36. On the other hand, a frame member 37 is punched into a frame shape from a sheet-like body having elasticity with both surfaces being adhesive surfaces. The frame member 37 is fixed to the outer peripheral portion of only the resin sheet 35 of the vibrating body 36 to obtain the target piezoelectric sounding element 31.
[0026]
Next, a detailed description will be given including a specific shape for realizing an actual high sound quality speaker.
The piezoelectric speaker converts the in-plane expansion / contraction strain of the piezoelectric element into bending in a direction perpendicular to the surface, and generates a sound wave by bending vibration of the surface. A general acoustic signal has a band of about 20 Hz to 20 kHz, and a number of surface resonance modes occur in the vibration mode of the piezoelectric sounding element within this band. When a significant difference in sound pressure due to a difference in signal frequency occurs due to the influence of the surface resonance, the sound quality is significantly deteriorated. Therefore, in order to achieve high sound quality, it is necessary to minimize the change in sound pressure due to frequency.
[0027]
In the piezoelectric sounding element, for example, as shown in FIGS. ₁ , 33 ₂ Then, the difference between the sound pressure maximum point and the sound pressure minimum point due to the frequency increases. This is because resonance at a specific frequency is likely to occur because the vertical and horizontal dimensions are equal.
In order to prevent this, as shown in FIGS. 5A, 5B and 5C, the piezoelectric element 33 has an elliptical, rectangular, or oval shaped element 33. ₃ , 33 ₄ , 33 ₅ In this case, the resonance mode can be dispersed due to the difference in the vertical and horizontal dimensions, so that the sound quality is improved.
[0028]
FIG. 8 shows a piezoelectric sounding element 31 according to the present embodiment having an elastic frame member 37 (see FIG. 6) and a piezoelectric sounding element 41 according to a comparative example having a non-elastic frame member 47 (see FIG. 6). 8 is a graph showing acoustic characteristics in comparison with FIG. 7). In the figure, a curve I indicated by a solid line is a characteristic of the piezoelectric sounding element 31 of the present embodiment, and a curve II indicated by a broken line is a characteristic of the piezoelectric sounding element 41 of the comparative example. Both have almost the same acoustic characteristics. According to FIGS. 8, 6 and 7, when the piezoelectric sounding element 31 of the present embodiment has the same acoustic characteristics as the piezoelectric sounding element 41 of the comparative example of FIG. It is recognized that smaller sizes can be formed.
The piezoelectric sounding element 31 in the present embodiment of FIG. 6 has external dimensions GX = 32 mm, GY = 26 m, external dimensions of the diaphragm 32 SSX = 26, SSY = 20 mm, and the frame member 37 is, for example, manufactured by Nitto Denko Corporation. Using a special foamed polyethylene double-sided adhesive tape. The acoustic characteristic at this time is a curve I in FIG. On the other hand, the piezoelectric sounding element 41 in the comparative example of FIG. 7 has outer dimensions of GX = 32 mm, GY = 26 mm, outer dimensions of the diaphragm 32 of SSX = 26 mm, and SSY = 22 mm. It constituted using. Other configurations are the same for both piezoelectric sounding elements 31 and 41, and are the same as those in FIG. 3. Therefore, corresponding portions are denoted by the same reference numerals and redundant description is omitted. The piezoelectric element 33 is formed in an elliptical shape, the diaphragm 32 is formed of a 42 alloy material (Fe-Ni alloy) having a thickness of 30 μm or 50 μm, and each of the rectangular corners is formed with R = 3 mm. Thickness d manufactured by Denko ₁ = 50 μm, and the thickness d2 of the vibrating body including the piezoelectric vibrating plate and the resin sheet was set to 0.25 mm to 0.3 mm.
[0029]
As shown in FIG. 8, both piezoelectric sounding elements 31 and 41 were made small for the same acoustic characteristics, but still in a low frequency region of 600 Hz or less, the piezoelectric sounding elements 31 and 41 of the present embodiment are still smaller. It is recognized that the acoustic characteristics are better.
[0030]
On the other hand, in the present embodiment, a region of only the resin sheet of FX = FY = about 0.5 mm is secured between the outer peripheral portion of the diaphragm 32 and the inner peripheral circle of the frame member 37. Further, in the case of the configuration supported by the flexible frame member 37 of the present embodiment, it is necessary to set dimensions in consideration of the flatness of the frequency characteristics of sound pressure, and SX / SY in SX> SY or SSX> SSY, or The SSX / SSY ratio is important. As for the method of determining the dimensions, first, the SX value is obtained based on the longitudinal dimension of the piezoelectric element to be used.
[0031]
According to the above-described piezoelectric sounding element 31 according to the present embodiment, since the frame member 37 having a required elasticity is integrally provided and the frame member 37 is directly joined to the fixing portion of the device, By optimizing the dimensions and the like, a small size and high sound quality can be achieved. In such a piezoelectric sounding element 31, for example, in a state before being mounted in the device, a release paper is attached to the mounting surface of the frame member 37 and placed. The mounting surface of the frame member is protected by the release paper. When mounting the piezoelectric sounding element 31 in a device, the release paper can be peeled off, attached to a predetermined location, and mounted by applying a slight pressure. The frame member 37 itself has a function of preventing chattering noise, and there is no need to use a cushion material for preventing chattering noise, which is conventionally performed well. In the present embodiment, it basically has durability against a thermal shock of −40 ° C. to + 85 ° C. Also, in other tests such as a drop impact, there was no breakage by a drop test of about 1 m with a dummy machine mounted with a weight of 250 g. The weight of the piezoelectric sounding element 31 of the embodiment shown in FIG. 6 is as light as about 0.7 g.
[0032]
On the other hand, in the piezoelectric sounding element 31 according to the above-described embodiment, the piezoelectric vibrating plate 34 is covered with the resin sheet 35, and the outermost peripheral portion of the resin sheet 35 is provided on the housing of the device via the frame member 37. The following effects can be achieved by adopting a configuration in which the support is made.
(1) The damping ratio of the resin sheet 35 itself is larger than the material-specific damping ratio of the metal material or the plastic material constituting the piezoelectric diaphragm, and the damping effect of the resin sheet 35 causes the damping of the piezoelectric diaphragm itself. The effect can be enhanced. By this effect, the sound pressure difference between the peak and the valley near the resonance point can be suppressed. Thereby, flatness of the sound pressure frequency characteristic can be obtained.
(2) By covering all the electrode surfaces of the piezoelectric vibrating plate with the resin sheet 35, all the electrode surfaces other than the terminal portions are insulated and covered with the resin sheet 35, and the insulation of the electrode surfaces can be secured. At the same time, there is also an effect of suppressing generation of cracks and cracks in the piezoelectric element portion due to external force.
[0033]
The piezoelectric sounding element according to the present invention can be applied to a structure in which a piezoelectric element is bonded to one surface of a vibration plate (usually a monomorph type) and a structure in which a piezoelectric element is bonded to both surfaces of a vibration plate (usually a bimorph type).
[0034]
9 to 11 show another embodiment of the piezoelectric sounding element of the present invention.
The piezoelectric sounding element 42 shown in FIG. 9 is formed by bonding a piezoelectric element 33 to one surface of a vibrating plate 32 made of a thin metal plate and forming a piezoelectric vibrating plate 51 provided with an electrode 38 on the surface of the piezoelectric element 33. Is covered with a resin sheet 35 [35 A, 35 B], and a frame member 37 is fixed to an outer peripheral portion of the resin sheet 35.
[0035]
The piezoelectric sounding element 43 shown in FIG. 10 uses a bimorph type piezoelectric vibrating plate 34 in which piezoelectric elements 33A and 33B are adhered to both surfaces of a vibrating plate 32 made of a thin metal plate, and electrodes 38 are formed on the surfaces of the piezoelectric elements 33A and 33B. One surface of the piezoelectric vibrating plate 34 is covered with a resin sheet 35A which is slightly larger than the piezoelectric vibrating plate 34, and the other surface of the piezoelectric vibrating plate 34 is covered with a resin sheet 35B having the same size as the piezoelectric vibrating plate 34; The frame member 37 is fixed to the outer peripheral portion of the resin sheet 35A.
[0036]
The piezoelectric sounding element 44 shown in FIG. 11 uses a bimorph type piezoelectric vibrating plate 34 in which piezoelectric elements 33A and 33B are adhered to both surfaces of a vibrating plate 32 made of a thin metal plate, and electrodes 38 are formed on the surfaces of the piezoelectric elements 33A and 33B. One surface of the piezoelectric vibrating plate 34 is covered with a resin sheet 35A which is slightly larger than the piezoelectric vibrating plate 34, and the frame member 37 is fixed to the outer peripheral portion of the resin sheet 35A. In addition, although not shown, a configuration in which the frame member 37 is directly fixed to the outer peripheral portion of the vibration plate without covering the piezoelectric vibration plate with the resin sheet may be adopted.
[0037]
The piezoelectric sounding element of the present invention is applied to a speaker, a receiver, other sounding elements, and the like.
[0038]
The piezoelectric sound generating element of the present invention can be configured to be delivered in the form of an aggregate sheet in which a plurality of piezoelectric sound elements are arranged. FIG. 12 shows a piezoelectric sounding element having a collective sheet form and a method of manufacturing the same.
First, as shown in FIG. 12A, a sheet member 52 for a frame member is prepared in which release papers 51 [51A, 51B] are arranged on both sides of a strip-shaped raw material sheet 37 'to be the frame member 37.
Next, as shown in FIG. 12B, the sheet member 52 for a frame member is punched with the release paper 51 attached so that an opening 53 is formed in a portion corresponding to the diaphragm. A plurality of the openings 53 are formed at predetermined intervals along the belt-shaped sheet member 52 for a frame member. This punching is performed using a continuous punching machine. Then, one release paper 51A is peeled off.
[0039]
On the other hand, as shown in FIG. 12C, a plurality of piezoelectric vibrating plates 34 from which the lead wires 54 are respectively led are arranged at predetermined intervals in a band shape, and both sides of each piezoelectric vibrating plate 34 are formed of two common band-shaped resin sheets. A sheet member 55 for a piezoelectric vibrating plate covered with the sheet 35 [35A, 35B] is prepared.
[0040]
Next, as shown in FIG. 12D, the piezoelectric vibrating plate 34 is positioned on the exposed surface of the raw material sheet 37 ′ of the sheet member 52 for the frame member in FIG. The sheet-like members 55 for a diaphragm are overlapped and bonded. Next, a cut 56 is formed by a cutter or the like over the entirety of the release paper 51B and the resin sheet 35 covering the piezoelectric vibration plate 34 so that a part of the release paper 51B remains at a position between the adjacent piezoelectric vibration plates 34. . Thus, a collective sheet form 57 in which the plurality of piezoelectric sounding elements 31 are arranged so as to adhere to the release paper 51B is obtained.
[0041]
According to the collective sheet form 57 according to the present embodiment, since the piezoelectric sounding elements 31 can be handled in an assembled state, quantity control can be easily performed, and the piezoelectric sounding elements 31 can be easily detached from the release paper 51B. , Etc. have practical advantages. As described above, in the present embodiment, by providing the frame member 37, it is possible to efficiently manufacture the piezoelectric sounding element 31 using the standard delivery form of the material.
[0042]
【The invention's effect】
According to the piezoelectric sounding element of the present invention, by expanding the vibration region of the vibrating body, it is possible to improve the acoustic characteristics if the same shape is obtained, and to reduce the size if the same acoustic characteristics are obtained. it can. The member that deforms following the vibration fixed to the vibrator also has a function of absorbing shock, and can also improve the shock resistance reliability of the piezoelectric sounding element. Since the deformable member absorbs the distortion even when the distortion is caused by a thermal change or the like, the reliability against a thermal shock or the like can be improved.
When the deformable member is formed of a double-sided adhesive tape, the member is easily adapted to the unevenness of the mounting surface, and even if a slight gap is formed, almost no chattering noise is generated. The attachment of the piezoelectric sounding element and the fixed portion can be easily performed without impairing the acoustic characteristics.
Since only the deformable member is interposed between the vibrating body and the fixed portion, the above-described effect can be achieved.
When the piezoelectric vibrating plate is covered with a resin sheet having an area larger than that of the piezoelectric vibrating plate to form a vibrating body, a region including only the resin sheet is formed on the outer peripheral portion of the piezoelectric vibrating plate, and peaks and valleys near the resonance point are formed. The sound pressure difference can be suppressed, and the sound pressure frequency characteristics can be flattened.
[0043]
According to the method of manufacturing a piezoelectric sounding element of the present invention, it is possible to accurately and easily manufacture a piezoelectric sounding element with improved acoustic characteristics or a reduced size.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a principle configuration of a piezoelectric sounding element according to the present invention.
FIG. 2A is an explanatory diagram illustrating a vibration state of a piezoelectric sounding element of a comparative example.
B is an explanatory view showing a vibration state of the piezoelectric sounding element of the present invention.
FIG. 3A is a sectional view showing one embodiment of a piezoelectric sounding element according to the present invention.
B is a bottom view of the piezoelectric sounding element of FIG. 2A.
FIG. 2C is a configuration diagram showing a state where the piezoelectric sounding element of FIG. 2A is attached to a housing of the device.
FIG. 4 is a plan view showing an embodiment of A and B piezoelectric elements.
FIG. 5 is a plan view showing an embodiment of an A to C piezoelectric element.
FIG. 6 is a configuration diagram of a piezoelectric sounding element according to the present embodiment used for measuring acoustic characteristics.
FIG. 6B is a configuration diagram showing a state in which the piezoelectric sound generating element of FIG. 6A is attached to a housing of the device.
FIG. 7 is a configuration diagram of a piezoelectric sounding element of a comparative example used for measurement of acoustic characteristics A.
FIG. 7B is a configuration diagram showing a state in which the piezoelectric sounding element of FIG. 7A is attached to a housing of the device.
8 is an acoustic characteristic diagram of the piezoelectric sounding element of FIG. 6 and the piezoelectric sounding element of FIG. 7;
FIG. 9 is a cross-sectional view showing another embodiment of the piezoelectric sounding element according to the present invention.
FIG. 10 is a sectional view showing another embodiment of the piezoelectric sounding element according to the present invention.
FIG. 11 is a sectional view showing another embodiment of the piezoelectric sounding element according to the present invention.
12A to 12D are manufacturing process charts showing a form of a collective sheet of the piezoelectric sounding element according to the present invention and a manufacturing method thereof.
FIG. 13 is a configuration diagram showing an example of a conventional piezoelectric sounding element.
14A and 14B are configuration diagrams of a conventional piezoelectric buzzer.
[Explanation of symbols]
21, 31,... Piezoelectric sounding element, 22, 32,... Diaphragm, 23, 33 [33A, 33B], 33 ₁ , 33 ₂ , 33 ₃ , 33 ₄ , 33 ₅ ..Piezoelectric elements, 24, 34..Piezoelectric vibration plates, 25, 37..Frame members, 26..Cases, 27..Openings, 35 [35A, 35B] .. Resin sheets, 36..Vibrators, 38..Electrode

Claims (7)

Having a vibrating body having at least a piezoelectric vibration plate composed of a piezoelectric element and a vibration plate to which the piezoelectric element is attached,
A piezoelectric sounding element characterized in that the vibrating body is joined to a fixed part via a member that deforms following the vibration of the vibrating body. 2. The piezoelectric sounding element according to claim 1, wherein said piezoelectric sounding element is formed of a double-sided adhesive tape. 2. The piezoelectric sounding element according to claim 1, wherein only the deformable member is interposed between the vibrating body and the fixed portion. The entire surface of at least one surface of the piezoelectric vibrating plate is covered with a resin sheet having an area larger than the piezoelectric vibrating plate to form the vibrating body,
2. The piezoelectric sound generating element according to claim 1, wherein a member that deforms following the vibration of the vibrator is fixed to the resin sheet. Forming a vibrating body having at least a piezoelectric vibrating plate having a piezoelectric element attached to the vibrating plate, and fixing a member that deforms following the vibration of the vibrating body to an outer peripheral portion of the vibrating body. Of manufacturing a piezoelectric sounding element. The method according to claim 5, wherein the deformable member is formed of a double-sided adhesive tape. Forming the vibrating body by covering the entire surface of at least one surface of the piezoelectric vibration plate with a resin sheet having an area larger than the piezoelectric vibration plate,
6. The method according to claim 5, wherein a member that deforms following the vibration of the vibrator is fixed to the resin sheet.

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