JP2014068157A - Sound generator, sound generation device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain excellent frequency characteristics of sound pressure.SOLUTION: A sound generator comprises: an exciter; a flat vibrating body; and a resin material. The exciter vibrates by receiving an electric signal. The exciter is attached to the vibrating body, which vibrates together with the exciter by the vibration of the exciter. The resin material is provided integrally with the vibrating body and exciter, with at least a part of the vibrating body being exposed.

Description

  Embodiments of the disclosure relate to a sound generator, a sound generation device, and an electronic apparatus.

  Conventionally, an acoustic generator using a piezoelectric element is known (see, for example, Patent Document 1). Such an acoustic generator is configured to vibrate a diaphragm by applying a voltage to a piezoelectric element attached to the diaphragm to vibrate, and to output sound by actively utilizing resonance of the vibration.

  In addition, since such a sound generator can use a thin film such as a resin film for the diaphragm, it can be made thinner and lighter than a general electromagnetic speaker.

  In addition, when using a thin film for a diaphragm, the thin film is supported in a state in which a uniform tension is applied, for example, by being sandwiched from a thickness direction by a pair of frame members so as to obtain excellent acoustic conversion efficiency. Is required.

JP 2004-023436 A

  However, the conventional acoustic generator described above actively uses the resonance of the diaphragm that is uniformly tensioned, and therefore, in the frequency characteristics of the sound pressure, the peak (the portion where the sound pressure is higher than the surroundings) and the dip There is a problem that high quality sound quality is difficult to obtain due to the fact that the sound pressure is lower than the surrounding area.

  One embodiment of the present invention has been made in view of the above, and an object thereof is to provide an acoustic generator, an acoustic generator, and an electronic apparatus that can obtain a favorable frequency characteristic of sound pressure.

  An acoustic generator according to an aspect of an embodiment includes an exciter, a flat vibrating body, and a resin material. The exciter vibrates upon receiving an electrical signal. The vibrator is attached with the exciter, and vibrates with the exciter due to vibration of the exciter. The resin material is provided so as to be integrated with the vibrator and the exciter while exposing at least a part of the vibrator.

  According to one aspect of the embodiment, a favorable sound pressure frequency characteristic can be obtained.

FIG. 1A is a schematic plan view showing a schematic configuration of a basic sound generator. 1B is a cross-sectional view taken along line A-A ′ of FIG. 1A. FIG. 2 is a diagram illustrating an example of frequency characteristics of sound pressure. FIG. 3A is a schematic cross-sectional view showing the configuration of the sound generator according to the embodiment. FIG. 3B is a schematic plan view showing the configuration of the sound generator according to the embodiment. FIG. 4A is a schematic plan view (part 1) showing another example of arrangement of resin materials. FIG. 4B is a schematic cross-sectional view taken along line C-C ′ shown in FIG. 4A. FIG. 4C is a schematic plan view (part 2) showing another example of arrangement of the resin material. FIG. 5 is a schematic plan view (part 3) showing another example of arrangement of the resin material. FIG. 6A is a diagram illustrating a configuration of the sound generation device according to the embodiment. FIG. 6B is a diagram illustrating a configuration of the electronic device according to the embodiment.

  Hereinafter, embodiments of a sound generator, a sound generator, and an electronic device disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

  First, prior to the description of the sound generator 1 according to the embodiment, a schematic configuration of a basic sound generator 1 ′ will be described with reference to FIGS. 1A and 1B. 1A is a schematic plan view showing a schematic configuration of the acoustic generator 1 ′, and FIG. 1B is a cross-sectional view taken along line A-A ′ of FIG. 1A.

  For ease of explanation, FIGS. 1A and 1B illustrate a three-dimensional orthogonal coordinate system including a Z-axis having a vertically upward direction as a positive direction and a vertically downward direction as a negative direction. Such an orthogonal coordinate system may also be shown in other drawings used in the following description.

  Moreover, below, about the component comprised by two or more, a code | symbol may be attached | subjected only to one part among several, and provision of a code | symbol may be abbreviate | omitted about others. In such a case, it is assumed that a part with the reference numeral and the other have the same configuration.

  Moreover, in FIG. 1A, illustration of the resin material 7 (described later) is omitted. For easy understanding, FIG. 1B greatly exaggerates the sound generator 1 ′ in the thickness direction (Z-axis direction).

  As shown in FIG. 1A, the sound generator 1 ′ includes a frame body 2, a diaphragm 3, and a piezoelectric element 5. As shown in FIG. 1A, in the following description, the case where there is one piezoelectric element 5 is illustrated, but the number of piezoelectric elements 5 is not limited.

  The frame body 2 is composed of two frame members having a rectangular frame shape and the same shape, and functions as a support body that supports the diaphragm 3 by sandwiching the peripheral edge portion of the diaphragm 3. The diaphragm 3 has a plate-like or film-like shape, and its peripheral portion is sandwiched and fixed by the frame body 2 and is flattened in a state where tension is uniformly applied within the frame of the frame body 2. Supported.

  A portion of the diaphragm 3 inside the inner periphery of the frame 2, that is, a portion of the diaphragm 3 that is not sandwiched between the frames 2 and can vibrate freely is referred to as a vibrating body 3 a. That is, the vibrating body 3 a is a portion that has a substantially rectangular shape within the frame of the frame body 2.

  The diaphragm 3 can be formed using various materials such as resin and metal. For example, the diaphragm 3 can be made of a resin film such as polyethylene or polyimide having a thickness of about 10 to 200 μm.

  Further, the thickness and material of the frame body 2 are not particularly limited, and can be formed using various materials such as metal and resin. For example, a stainless steel member having a thickness of about 100 to 1000 μm can be suitably used as the frame 2 because it has excellent mechanical strength and corrosion resistance.

  Although FIG. 1A shows the frame 2 in which the shape of the inner region is substantially rectangular, it may be a polygon such as a parallelogram, trapezoid, or regular n-gon. In the present embodiment, as shown in FIG.

  Further, in the above description, the case where the frame body 2 is configured by two frame members and the peripheral portion of the diaphragm 3 is sandwiched and supported by the two frame members is described as an example. It is not a thing. For example, the frame body 2 may be constituted by a single frame member, and the peripheral edge portion of the diaphragm 3 may be bonded and supported to the frame body 2.

  The piezoelectric element 5 is an exciter that is provided by being affixed to the surface of the vibrating body 3a and that excites the vibrating body 3a by receiving a voltage to vibrate.

  As shown in FIG. 1B, the piezoelectric element 5 includes, for example, a laminate in which piezoelectric layers 5a, 5b, 5c, and 5d made of four ceramic layers and three internal electrode layers 5e are alternately laminated, Surface electrode layers 5f and 5g formed on the upper and lower surfaces of the laminate, and external electrodes 5h and 5j formed on the side surfaces where the internal electrode layer 5e is exposed. The lead terminals 6a and 6b are connected to the external electrodes 5h and 5j.

  The piezoelectric element 5 has a plate shape, and the main surface on the upper surface side and the lower surface side has a polygonal shape such as a rectangular shape or a square shape. The piezoelectric layers 5a, 5b, 5c, and 5d are polarized as shown by arrows in FIG. 1B. In other words, polarization is performed such that the direction of polarization with respect to the direction of the electric field applied at a certain moment is reversed between one side and the other side in the thickness direction (Z-axis direction in the figure).

  When a voltage is applied to the piezoelectric element 5 via the lead terminals 6a and 6b, for example, at a certain moment, the piezoelectric layers 5c and 5d on the side bonded to the vibrating body 3a contract and the upper surface of the piezoelectric element 5 is compressed. The piezoelectric layers 5a and 5b on the side are deformed so as to extend. Therefore, by applying an AC signal to the piezoelectric element 5, the piezoelectric element 5 can bend and vibrate, and the vibrating body 3a can be bent.

  In addition, the main surface of the piezoelectric element 5 is joined to the main surface of the vibrating body 3a by an adhesive such as an epoxy resin.

  The materials constituting the piezoelectric layers 5a, 5b, 5c and 5d are conventionally used, such as lead-free piezoelectric materials such as PZT (lead zirconate titanate), Bi layered compounds, and tungsten bronze structure compounds. Piezoelectric ceramics can be used.

  Various metal materials can be used as the material of the internal electrode layer 5e. For example, when a metal component composed of silver and palladium and a ceramic component constituting the piezoelectric layers 5a, 5b, 5c, and 5d are contained, the piezoelectric layers 5a, 5b, 5c, and 5d and the internal electrode layer 5e Since the stress due to the difference in thermal expansion can be reduced, the piezoelectric element 5 free from stacking faults can be obtained.

  The lead terminals 6a and 6b can be formed using various metal materials. For example, if the lead terminals 6a and 6b are configured using flexible wiring in which a metal foil such as copper or aluminum is sandwiched between resin films, the height of the piezoelectric element 5 can be reduced.

  Further, as shown in FIG. 1B, the sound generator 1 ′ further includes a resin material 7 that is filled in the frame of the frame 2 so as to cover the surfaces of the piezoelectric element 5 and the vibrating body 3a and is formed in a layer shape. .

  For the resin material 7, for example, an acrylic resin or an epoxy resin can be used. The resin material 7 is filled and cured to be integrated with the vibrating body 3 a and the piezoelectric element 5, and constitutes one composite vibrating body together with the vibrating body 3 a and the piezoelectric element 5.

  In addition, since the moderate damping effect can be induced by completely embedding the piezoelectric element 5 in the resin material 7, the effect of suppressing the resonance phenomenon and suppressing the peak or dip in the frequency characteristic of the sound pressure can be reduced. Can be obtained.

  In FIG. 1B, the piezoelectric element 5 is a bimorph multilayer piezoelectric element. However, the piezoelectric element 5 is not limited to this. For example, a unimorph type in which the expanding and contracting piezoelectric element 5 is attached to the vibrating body 3a. It does not matter.

  Incidentally, FIG. 1B shows a vibrating body 3a that is flatly supported in a state where tension is uniformly applied in the frame of the frame body 2, a piezoelectric element 5 provided on the surface of the vibrating body 3a, and A resin material 7 is shown which is integrated and formed by cutting the surface flat at the height of the frame 2.

  That is, it can be said that the composite vibration body constituted by the vibration body 3a, the piezoelectric element 5, and the resin material 7 is shaped as a whole and has a so-called symmetrical shape. In such a case, a peak, dip, or distortion caused by resonance induced by the vibration of the piezoelectric element 5 occurs, so that the sound pressure changes suddenly at a specific frequency, and it is difficult to flatten the frequency characteristics of the sound pressure. .

  This point will be specifically described with reference to FIG. FIG. 2 is a diagram illustrating an example of frequency characteristics of sound pressure. As already described, when the composite vibrating body constituted by the vibrating body 3a, the piezoelectric element 5, and the resin material 7 is shaped and has a shape having symmetry as a whole, for example, the vibrating body 3a or the resin material 7 is used. The Young's moduli of each are aligned overall.

  However, in such a case, since the peak concentrates on a specific frequency due to resonance of the vibrating body 3a and degenerates, steep peaks and dips are likely to be scattered throughout the entire frequency region as shown in FIG.

  As an example, attention is paid to a portion surrounded by a broken closed curve PD in FIG. When such a peak P occurs, the sound pressure varies depending on the frequency, making it difficult to obtain good sound quality.

  In such a case, as shown in FIG. 2, the height of the peak P is lowered (see the arrow 201 in the figure), the peak width is widened (see the arrow 202 in the figure), and the peak P or dip (not shown) is reduced. It is effective to take measures to make it smaller.

  Therefore, in this embodiment, the resin material 7 is provided so as to darely expose at least a part of the vibrating body 3a. In other words, the resin material 7 is provided so that the surface of the vibrating body 3a and the surface of the resin material 7 are mixed when viewed in plan.

  That is, by mixing portions having different Young's moduli and reducing the symmetry of the above-described composite vibration body, the resonance frequencies are not partially aligned. As a result, the resonance mode degeneracy is solved and dispersed, the height of the peak P is lowered, and the peak width is widened.

  Hereinafter, the sound generator 1 according to the embodiment will be specifically described sequentially with reference to FIGS. 3A to 5. 3A to 5 used in the following description, lowercase alphabets such as “7a” and “7b” are assigned to the reference numeral “7” of the resin material 7 to provide a plurality of resins. Each material 7 may be indicated individually.

  FIG. 3A is a schematic cross-sectional view showing the configuration of the sound generator 1 according to the embodiment. 3A is a schematic cross-sectional view taken along the line A-A ′ of FIG. 1A. FIG. 3B is a schematic plan view showing the configuration of the sound generator 1 according to the embodiment.

  As shown in FIG. 3A, the sound generator 1 according to the embodiment is provided with the resin material 7 so as to expose at least a part of the vibrating body 3a. For example, FIG. 3A shows a resin material 7a provided so as to cover the entire piezoelectric element 5, and a resin material 7b and a resin material 7c provided separately from the resin material 7a.

  It is assumed that the thickness h1 of the resin material 7a, the thickness h2 of the resin material 7b, and the thickness h3 of the resin material 7c are in a relationship of h1> h2> h3. Moreover, as shown in FIG. 3A, the cross-sectional shape of the resin materials 7a and 7c is a substantially small mountain shape, and the cross-sectional shape of the resin material 7b is a substantially rectangular shape with R at the corners.

  Moreover, as shown in FIG. 3B, for example, the sound generator 1 further includes a resin material 7d. That is, a plurality of resin materials 7 are provided on the surface of the vibrating body 3a as in the resin materials 7a to 7d. As shown in FIG. 3B, the planar shape of the resin materials 7a, 7c and 7d is substantially elliptical, and the planar shape of the resin material 7b is substantially rectangular with R at the corners.

  First, the resin material 7 is provided so as to cover the entirety of the piezoelectric element 5 that is a vibration source like the resin material 7a, thereby shifting the resonance frequency around the piezoelectric element 5 to the low frequency side, thereby increasing the peak. P can be made gentler as it approaches the piezoelectric element 5. That is, the sound pressure peak P at the resonance point can be varied, and the frequency characteristic of the sound pressure can be flattened. Therefore, a favorable frequency characteristic of sound pressure can be obtained.

  Further, the resin material 7 is provided in a plurality of scattered manners like the resin materials 7a to 7d, so that the resonance frequency is shifted to the low frequency side in the portion where the resin materials 7a to 7d exist, and the sound pressure at the resonance point is obtained. The peak P can be varied. That is, since the frequency characteristic of the sound pressure can be flattened, a good frequency characteristic of the sound pressure can be obtained.

  Note that it is preferable that the plurality of such resin materials 7 be scattered in an asymmetric random arrangement that lowers the symmetry of the composite vibrator, for example, as shown in FIG. 3B. As a result, the symmetry of the composite vibrator can be reduced and the resonance frequencies can be partially not aligned. That is, the sound pressure peak P at the resonance point can be varied, and the frequency characteristic of the sound pressure can be flattened. Therefore, a favorable frequency characteristic of sound pressure can be obtained.

  Moreover, it is preferable that the resin material 7 is nonuniform in thickness or its planar shape like resin material 7a-7d. As a result, the symmetry of the composite vibrator can also be lowered, and the frequency to be shifted can be varied for each portion where the resin materials 7a to 7d are present. That is, the sound pressure peak P at the resonance point can be varied, and the frequency characteristic of the sound pressure can be flattened. Therefore, a favorable frequency characteristic of sound pressure can be obtained.

  Note that the thickness or the planar shape is not uniform because at least one of the resin materials 7 is different from the other resin materials 7.

  Moreover, the formation method of the resin material 7 is not specifically limited. For example, the material for forming the resin material 7 may be provided by discharging the resin material 7 from the nozzle (not shown) toward the vibrating body 3 a and the piezoelectric element 5.

  The resin material 7 may be provided by a screen printing method. In the case of such a screen printing technique, it is possible to obtain an effect that it can contribute to cost reduction in mass production of the sound generator 1.

  By the way, the resin material 7 may be provided along the boundary between the frame body 2 and the vibrating body 3a when seen in a plan view. Such a case will be described next with reference to FIGS. 4A to 4C. 4A is a schematic plan view (part 1) showing another example of arrangement of the resin material 7, and FIG. 4B is a schematic cross-sectional view taken along the line C-C 'shown in FIG. 4A. FIG. 4C is a schematic plan view (part 2) showing another example of arrangement of the resin material 7.

  As shown in FIG. 4A, the resin material 7 may be provided so as to be scattered along the boundary between the frame body 2 and the vibrating body 3a when viewed in plan. In such a case, it may be provided away from the frame 2 like the resin material 7e, or may be provided in contact with the inner wall of the frame 2 like the resin material 7f (see FIG. 4B).

  Thus, by providing the resin material 7 along the boundary between the frame body 2 and the vibration body 3a in plan view, it is possible to suppress the propagation of vibration around the frame body 2 that is a vibration node. Therefore, it is possible to cause a deviation between the incident speed and the reflection speed of the vibration from the piezoelectric element 5.

  That is, since the sound pressure peak P at the resonance point can be varied and the frequency characteristic of the sound pressure can be flattened, a favorable frequency characteristic can be obtained.

  In addition, when provided so as to be scattered along the boundary between the frame body 2 and the vibrating body 3a in this way, for example, as shown in the resin material 7e of FIG. Is preferred (line B and line B ′ in FIG. 4A).

  Thereby, since the symmetry of the composite vibrator can be reduced, the resonance frequencies can be partially unbalanced, and the sound pressure peak P at the resonance point can be varied. That is, it is possible to flatten the frequency characteristic of sound pressure and obtain a good frequency characteristic of sound pressure.

  Moreover, when providing the resin material 7 along the boundary of the frame 2 and the vibrating body 3a, as shown to FIG. 4A, it is not restricted to the case where it is scattered. For example, as shown as a resin material 7g in FIG. 4C, a joint between the frame body 2 and the vibrating body 3a may be continuously sealed.

  By the way, the case where the resin material 7 is dispersed and arranged in an island shape has been described as an example so far. However, after the resin material 7 is formed as a continuous region in a plan view, A part of the vibrating body 3a may be exposed by providing open pores in the resin material 7.

  Such a case will be described with reference to FIG. FIG. 5 is a schematic plan view (No. 3) showing another example of arrangement of the resin material 7.

  As shown in FIG. 5, the resin material 7 is formed as a continuous layered region filled in the frame of the frame body 2, and at least a part of the vibrating body 3 a is formed like the voids V <b> 1 to V <b> 5. It may be provided with open pores to be exposed.

  Moreover, it is preferable that the open pores are scattered in an asymmetric random arrangement that lowers the symmetry of the composite vibration body, such as the voids V1 to V5. Moreover, it is preferable that the exposed area of the vibrating body 3a in each open pore (that is, the size of the open pore) is not uniform.

  FIG. 5 shows voids V1 to V3 that have the same shape but different sizes, and voids V4 that are substantially the same as the void V2 but have different directions, and voids that have clearly different shapes when viewed in plan. V5 is illustrated.

  First, by forming the resin material 7 as a continuous region, the resin continuously covers the periphery of the frame 2 and the piezoelectric element 5, which can contribute to suppression of abnormal resonance and harmonics. Therefore, the frequency characteristics of sound pressure can be flattened.

  Further, by arranging the open pores at random so as to reduce the symmetry of the composite vibrator, such as the voids V1 to V5, the resonance frequencies can be partially not aligned. That is, the sound pressure peak P at the resonance point can be varied, and the frequency characteristic of the sound pressure can be flattened.

  Further, by making the exposed area of the vibrating body 3a in each open pore non-uniform, the symmetry of the composite vibrating body can also be lowered and the frequency shifted for each portion where the resin material 7 does not exist can be made different. . That is, the sound pressure peak P at the resonance point can be varied, and the frequency characteristic of the sound pressure can be flattened. Therefore, a favorable frequency characteristic of sound pressure can be obtained.

  Also, by making the orientation and shape of the open pores in a plan view non-uniform, the symmetry of the composite vibrator can also be lowered and the resonance frequencies can be partially not aligned. That is, the sound pressure peak P at the resonance point can be varied, and the frequency characteristic of the sound pressure can be flattened.

  Note that the size, direction, and shape of the open pores are not uniform because at least one of the open pores is different from other open pores.

  Next, a sound generation device and an electronic apparatus equipped with the sound generator 1 according to the embodiment described so far will be described with reference to FIGS. 6A and 6B. FIG. 6A is a diagram illustrating a configuration of the sound generation device 20 according to the embodiment, and FIG. 6B is a diagram illustrating a configuration of the electronic device 50 according to the embodiment. In addition, in both figures, only the component required for description is shown and description about a general component is abbreviate | omitted.

  The sound generation device 20 is a sound generation device such as a so-called speaker, and includes, for example, a sound generator 1 and a housing 30 that houses the sound generator 1 as shown in FIG. 6A. The housing 30 resonates the sound generated by the sound generator 1 and radiates the sound to the outside through an opening (not shown) formed in the housing 30. By having such a housing 30, for example, the sound pressure in a low frequency band can be increased.

  The sound generator 1 can be mounted on various electronic devices 50. For example, in FIG. 6B shown below, it is assumed that the electronic device 50 is a mobile terminal device such as a mobile phone or a tablet terminal.

  As shown in FIG. 6B, the electronic device 50 includes an electronic circuit 60. The electronic circuit 60 includes, for example, a controller 50a, a transmission / reception unit 50b, a key input unit 50c, and a microphone input unit 50d. The electronic circuit 60 is connected to the sound generator 1 and has a function of outputting an audio signal to the sound generator 1. The sound generator 1 generates sound based on the sound signal input from the electronic circuit 60.

  The electronic device 50 includes a display unit 50e, an antenna 50f, and the sound generator 1. Further, the electronic device 50 includes a housing 40 that accommodates these devices.

  6B shows a state in which each device including the controller 50a is accommodated in one housing 40, but the accommodation form of each device is not limited. In the present embodiment, it is sufficient that at least the electronic circuit 60 and the sound generator 1 are accommodated in one housing 40.

  The controller 50 a is a control unit of the electronic device 50. The transmission / reception unit 50b transmits / receives data via the antenna 50f based on the control of the controller 50a.

  The key input unit 50c is an input device of the electronic device 50 and accepts a key input operation by an operator. The microphone input unit 50d is also an input device of the electronic device 50, and accepts a voice input operation by an operator.

  The display unit 50e is a display output device of the electronic device 50, and outputs display information based on the control of the controller 50a.

  The sound generator 1 operates as a sound output device in the electronic device 50. The sound generator 1 is connected to the controller 50a of the electronic circuit 60, and emits sound upon application of a voltage controlled by the controller 50a.

  In FIG. 6B, the electronic device 50 is described as a portable terminal device. However, the electronic device 50 is not limited to the type of the electronic device 50, and may be applied to various consumer devices having a function of emitting sound. . For example, flat-screen TVs and car audio devices can of course be used for products having a function of emitting sound such as "speak", for example, various products such as vacuum cleaners, washing machines, refrigerators, microwave ovens, etc. .

  As described above, the sound generator according to the embodiment includes an exciter (piezoelectric element), a flat vibrating body, and a resin material. The exciter vibrates when an electric signal is input thereto. The vibrator is provided with the exciter, and vibrates with the exciter by the vibration of the exciter. The resin material is provided so as to be integrated with the vibrator and the exciter while exposing at least a part of the vibrator.

  Therefore, according to the sound generator according to the embodiment, it is possible to obtain a favorable frequency characteristic of sound pressure.

  In the above-described embodiment, the case where the piezoelectric element is provided on one main surface of the vibrating body is mainly described as an example. However, the present invention is not limited to this, and the piezoelectric element is provided on both surfaces of the vibrating body. It may be provided.

  Further, in the above-described embodiment, the case where the shape of the inner region of the frame is a substantially rectangular shape is taken as an example, and it may be a polygon, but is not limited thereto, and is not limited to a circle or an ellipse. It may be a shape.

  Further, in the above-described embodiment, the case where the diaphragm is configured by a thin film such as a resin film has been described as an example.

  In the above-described embodiment, the case where the support body that supports the vibrating body is a frame body and the periphery of the vibrating body is supported is described as an example. However, the present invention is not limited to this. For example, it is good also as supporting only the both ends of the longitudinal direction or a transversal direction of a vibrating body.

  In the above-described embodiment, the case where the exciter is a piezoelectric element has been described as an example. However, the exciter is not limited to the piezoelectric element, and has a function of vibrating when an electric signal is input. What is necessary is just to have.

  For example, an electrodynamic exciter, an electrostatic exciter, or an electromagnetic exciter well known as an exciter for vibrating a speaker may be used.

  The electrodynamic exciter is such that an electric current is passed through a coil disposed between the magnetic poles of a permanent magnet to vibrate the coil. The electrostatic exciter is composed of two metals facing each other. A bias and an electric signal are passed through the plate to vibrate the metal plate, and an electromagnetic exciter is an electric signal that is passed through the coil to vibrate a thin iron plate.

  Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 1, 1 'Sound generator 2 Frame body 3 Diaphragm 3a Vibration body 5 Piezoelectric element 5a, 5b, 5c, 5d Piezoelectric layer 5e Internal electrode layer 5f, 5g Surface electrode layer 5h, 5j External electrode 6a, 6b Lead terminal 7 , 7a to 7g Resin material 20 Sound generator 30, 40 Case 50 Electronic device 50a Controller 50b Transmitter / receiver 50c Key input unit 50d Microphone input unit 50e Display unit 50f Antenna 60 Electronic circuit P peak V1 to V5 voids (open holes)
h1, h2, h3 thickness

Claims (11)

An exciter that vibrates upon receipt of an electrical signal;
A flat vibrator that is attached to the exciter and vibrates with the exciter by vibration of the exciter;
An acoustic generator comprising: a resin material provided so as to be integrated with the vibrator and the exciter while exposing at least a part of the vibrator. The resin material is
The sound generator according to claim 1, wherein the sound generator is provided so as to cover the entire exciter. The resin material is
The sound generator according to claim 1, wherein a plurality of the sound generators are provided on the surface of the vibrating body. At least one of the resin materials is
The acoustic generator according to claim 3, wherein the thickness or the shape in plan view is different from that of the other resin material. A support for supporting the vibrating body;
The resin material is
The acoustic generator according to any one of claims 1 to 4, wherein the acoustic generator is provided along a boundary between the support body and the vibrating body in a plan view. The support is a frame,
The vibrating body is supported in a frame of the frame,
The resin material is
The inside of the frame of the frame body is filled in layers so as to cover the exciter, and is provided with open pores that expose at least a part of the vibration body. Sound generator. The sound generator according to claim 6, wherein an exposed area of the vibrating body in at least one of the open pores is different from an exposed area of the vibrating body in the other open pores. The sound generator according to claim 1, wherein the vibrating body is made of a resin film. The acoustic generator according to any one of claims 1 to 8, wherein the exciter is a bimorph type stacked piezoelectric element. The sound generator according to any one of claims 1 to 9,
A sound generation device comprising: a housing that houses the sound generator. The sound generator according to any one of claims 1 to 9,
An electronic circuit connected to the acoustic generator;
A housing for housing the electronic circuit and the acoustic generator;
An electronic device having a function of generating sound from the sound generator.

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