JP5952426B2 - SOUND GENERATOR, SOUND GENERATOR, AND ELECTRONIC DEVICE - Google Patents

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.

Sound generator according to an aspect of the embodiment includes a exciter, the vibrating plate, and a support. The exciter vibrates upon receiving an electrical signal. The vibration plate is attached with the exciter, and vibrates with the exciter due to vibration of the exciter. The support body includes two frame members having substantially the same shape arranged so as to sandwich the outer peripheral portion of the diaphragm, and supports the vibration body substantially flat. Further, the support one hole portions even without less is provided in, the hole portion is a through hole passing through the two frame members.

  In addition, a sound generation device according to one aspect of the embodiment includes the sound generator described above and a housing that houses the sound generator.

  An electronic apparatus according to an aspect of the embodiment includes the above-described acoustic generator, an electronic circuit connected to the acoustic generator, and a housing that houses the electronic circuit and the acoustic generator. It has a function of generating sound from the sound generator.

  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 plan view showing the configuration of the sound generator according to the embodiment. FIG. 3B is a cross-sectional view taken along line B-B ′ of FIG. 3A. FIG. 3C is an enlarged view (part 1) of a corner C1 shown in FIG. 3B. FIG. 3D is an enlarged view (part 2) of the corner C1 shown in FIG. 3B. FIG. 3E is an enlarged view (part 1) of a corner C2 shown in FIG. 3B. FIG. 3F is an enlarged view (No. 2) of the corner C2 shown in FIG. 3B. FIG. 3G is a schematic cross-sectional view showing a modification of the “hole” in the axial direction. FIG. 3H (a) is a schematic plan view showing a configuration of an acoustic generator according to another embodiment, and FIG. 3H (b) is a cross-sectional view taken along the line C-C ′ of FIG. 3H (a). FIG. 4A is a schematic plan view showing a configuration of an acoustic generator according to a first modification. FIG. 4B is a schematic plan view showing the configuration of the sound generator according to the second modification. FIG. 5 is a schematic plan view showing the configuration of the sound generator according to the third modification. 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.

  In addition, in the following, with regard to a plurality of constituent elements, only one of the plurality of constituent elements may be assigned a reference numeral, and the other reference numerals may be omitted. In such a case, it is assumed that one with the reference numeral and the other have the same configuration.

  Moreover, in FIG. 1A, illustration of the resin layer 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 the same shape in a rectangular frame shape, and as a support body that supports the diaphragm 3 with the outer peripheral portion (peripheral portion) of the main surface of the diaphragm 3 sandwiched therebetween. Function. The diaphragm 3 has a plate-like shape or a film-like shape, and its outer peripheral portion (peripheral portion) is sandwiched and fixed by the frame body 2 and is uniformly tensioned in the frame of the frame body 2. It is supported in a substantially flat state.

  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 10 to 200 μm.

  Further, the thickness and material of the frame member constituting 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 100 to 5000 μm can be suitably used as the frame member constituting the frame body 2 because of its 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 frame body 2 is formed of two frame members as a laminate, and the outer peripheral portion (peripheral portion) of the diaphragm 3 is sandwiched and supported by the two frame members as an example. However, it is not limited to this. For example, the frame body 2 may be constituted by a single frame member, and the outer peripheral portion (peripheral portion) of the diaphragm 3 may be bonded and supported to the frame body 2. Further, the frame body 2 may be configured by laminating three or more frame members.

  The piezoelectric element 5 is an exciter that is provided on the surface of the vibration plate 3 (vibration body 3a) or the like and excites the vibration plate 3 (vibration body 3a) by oscillating upon application of a voltage. .

  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 diaphragm 3 (vibrating body 3a) contract, The piezoelectric layers 5a and 5b on the upper surface side of the piezoelectric element 5 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 plate 3 (the vibrating body 3a) can be bent.

  The main surface of the piezoelectric element 5 is bonded to the main surface of the diaphragm 3 (vibrating body 3a) with an adhesive such as an epoxy resin.

  The materials constituting the piezoelectric layers 5a, 5b, 5c, and 5d have conventionally been lead-free piezoelectric materials such as lead zirconate titanate, Bi layered compounds, and tungsten bronze structural compounds. The used 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 ′ is disposed so as to cover the surfaces of the piezoelectric element 5 and the diaphragm 3 (vibrating body 3a) in the frame 2 and the diaphragm 3 (vibration). The resin layer 7 integrated with the body 3a) and the piezoelectric element 5 is further provided.

  The resin layer 7 is preferably formed using, for example, an acrylic resin so that the Young's modulus is about 1 MPa to 1 GPa. In addition, since the moderate damping effect can be induced by embedding the piezoelectric element 5 in the resin layer 7, the resonance phenomenon can be suppressed, and the peak and dip in the frequency characteristic of the sound pressure can be suppressed small.

  FIG. 1B shows a state in which the resin layer 7 is formed so as to be the same height as the frame 2, but it is sufficient that the piezoelectric element 5 is embedded, for example, the resin layer 7 has a frame. It may be formed to be higher than the height of the body 2.

  In this way, the diaphragm 3 (vibrating body 3a), the piezoelectric element 5 and the resin layer 7 are integrated to form a composite vibrating body that vibrates integrally.

  In FIG. 1B, as the piezoelectric element 5, a bimorph-type laminated piezoelectric element is taken as an example. However, the piezoelectric element 5 is not limited to this. For example, the expanding and contracting piezoelectric element 5 is attached to the diaphragm 3 (vibrating body 3a). It may be a pasted unimorph type.

  By the way, as shown in FIGS. 1A and 1B, the diaphragm 3 (vibrating body 3 a) is supported substantially flat in a state where tension is uniformly applied in the frame of the frame body 2. In such a case, since a peak, a dip, or a distortion due to resonance induced by vibration of the piezoelectric element 5 occurs, the sound pressure changes rapidly at a specific frequency, and it is difficult to flatten the frequency characteristics of the sound pressure. .

  This point is illustrated in FIG. FIG. 2 is a diagram illustrating an example of frequency characteristics of sound pressure. As already described in the description of FIG. 1A, the diaphragm 3 (vibrating body 3 a) is supported substantially flat in a state where tension is uniformly applied within the frame of the frame body 2.

  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 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.

  Here, focus on the frame 2. As described above, the frame body 2 is a support body that supports the vibrating body 3a while applying a uniform tension. However, when the vibrating body 3a vibrates, the frame body 2a is also induced by resonance of the vibrating body 3a. The body 2 itself is also vibrating. The frame 2 returns a reflected wave to the vibrating body 3a. Therefore, the frame body 2 can be regarded as one of the components of the above-described composite vibration body that vibrates integrally.

  Therefore, in the present embodiment, at least one “hole” or “groove” is intentionally provided to the frame 2 as a support, thereby disturbing vibration waves around the “hole” or “groove”. Thus, the reflected wave returning from the frame body 2 to the vibrating body 3a is disturbed. Thus, the resonance frequency is made partially ununiform so that the resonance mode degeneracy is solved and dispersed, and 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. First, FIG. 3A is a schematic plan view showing the configuration of the sound generator 1 according to the embodiment. 3B is a cross-sectional view taken along line B-B ′ of FIG. 3A.

  In addition, in each drawing shown below including the schematic plan view of FIG. 3A, illustration of the resin layer 7 may be abbreviate | omitted similarly to FIG. 1A for convenience of explanation. In the following description, a symbol “H + numerical value” is assigned to each hole portion, but when these are collectively referred to, they are described as “hole portion” with no symbol added.

  As shown in FIG. 3A, the sound generator 1 includes a “hole” in the frame 2 as a support in addition to the sound generator 1 ′ shown in FIGS. 1A and 1B. Such “holes” are provided as holes H1 to H4 in the corners of the frame 2 as shown in FIG. 3A, for example.

  As described above, when the holes H1 to H4 are provided in the corners of the frame 2, vibration waves that propagate through the frame 2 and collide from both sides of the frame 2 forming the corners are further reduced. It can be violently disturbed around the holes H1 to H4.

  As a result, the resonance frequencies can be partially unbalanced, so that the sound pressure peak P at the resonance point can be varied and the frequency characteristics of the sound pressure can be flattened. That is, it is possible to obtain a favorable frequency characteristic of sound pressure.

  In addition, the “hole” is provided at a diagonal position (see the alternate long and short dash line d1 in the drawing), in other words, at a longer distance, like the holes H1 and H4 in FIG. 3A. The resonance frequency of the long low-frequency sound pressure can be partially not aligned.

  Thereby, the sound pressure peak P at the resonance point can also be varied, and the frequency characteristic of the sound pressure can be flattened. That is, it is possible to obtain a favorable frequency characteristic of sound pressure.

  3A illustrates the case where one hole portion H1 to H4 is provided in each of the four corners of the frame 2, but the number of “hole portions” is not limited.

  Here, the “hole” may be a shallow hole such as a so-called depression, or may be a clear hole formed with a predetermined depth. Further, the frame body 2 as the support body is composed of two frame members having substantially the same shape arranged so as to sandwich the outer peripheral portion of the diaphragm 3, and when a hole is provided in this, the hole portion shown in FIG. 3B Like H1, it may be formed as a through hole penetrating the two frame members, or may be formed as a non-through hole like the hole H2.

  Furthermore, as shown in FIG. 3H, a configuration in which a groove portion J is provided instead of the “hole portion” may be adopted. FIG. 3H (a) is a schematic plan view showing a configuration of an acoustic generator according to another embodiment, and FIG. 3H (b) is a cross-sectional view taken along the line CC ′ of FIG. 3H (a). .

  When the groove portion J extending in the width direction of the frame body 2 as shown in FIG. 3H is provided instead of the “hole portion”, the following effects can be obtained in addition to the effect of the “hole portion”.

  That is, when the groove portion J is provided from the inner side to the outer side in the width direction of the frame body 2, the shape of the groove portion J itself is deformed so that the opening portion opens and closes with the bottom portion of the groove portion J as a fulcrum. The frequency can be flattened. Furthermore, by arranging a plurality of such groove portions J, the region sandwiched between the groove portions J can be easily deformed and the resonance frequency can be flattened.

  Next, the details of the “hole” will be described. 3C and 3D are enlarged views (No. 1) and (No. 2) of the corner C1 shown in FIG. 3B. 3E and 3F are enlarged views (No. 1) and (No. 2) of the corner C2 shown in FIG. 3B.

  FIG. 3G is a schematic cross-sectional view showing a modification of the “hole” in the axial direction. 3G is a schematic cross-sectional view taken along line A-A ′ of FIG. 1A.

  As shown as a hole H1 in FIG. 3C, in the case where the frame 2 as a support body is composed of two frames 2 having substantially the same shape arranged so as to sandwich the outer periphery of the diaphragm 3, "May be formed as a through-hole penetrating the two frames 2. In this case, the vibration wave can be disturbed around the hole H1 in both the upper frame member and the lower frame member, and the vibration wave is also formed in the cavity inside the hole H1 in response to the vibration. The reflected wave from the body 2 to the vibrating body 3a can be further disturbed.

  As a result, the resonance frequencies can be partially unbalanced, so that the sound pressure peak P at the resonance point can be varied and the frequency characteristics of the sound pressure can be flattened. That is, it is possible to obtain a favorable frequency characteristic of sound pressure.

  Moreover, since the hole H1 is a through-hole, the surrounding frame body 2 is easily deformed. For this reason, when the sound pressure is high, the shape of the through hole itself is deformed by the frame 2 being deformed around the hole H1.

  Therefore, the resonance frequencies can be further partially unbalanced, so that the sound pressure peak P at the resonance point can be varied and the frequency characteristics of the sound pressure can be flattened. That is, it is possible to obtain a favorable frequency characteristic of sound pressure.

  In addition, after providing a through-hole with the drill etc. in the frame 2, and forming the hole H1, the diaphragm 3 is affixed on the frame 2, and a part re of the diaphragm 3 is provided in the hole H1. Can do. Furthermore, by providing a through hole in the diaphragm 3 inside the hole H1 with a drill or the like having a diameter smaller than that of the through hole of the frame body 2, a part re of the diaphragm 3 provided with the through hole inside the hole H1 is removed. Can be formed.

  Further, as shown in FIG. 3C, the two frame bodies 2 sandwiching the peripheral edge portion of the diaphragm 3 are provided with a through hole by a drill or the like to form a hole H1, and the diaphragm 3 is provided inside the hole H1. The part re can be formed (see the part surrounded by a closed closed line in the figure).

  And also by providing a part re of the diaphragm 3 inside the hole H1 in this way, the resonance frequency can be partially unaligned. This is because, when a vibration wave propagates through a hole H1 in which a part re of the diaphragm 3 is provided, a part re of the diaphragm 3 is freely deformed by the propagation to attenuate the vibration wave. Because.

  As a result, a phenomenon occurs in which the vibration wave propagating around the hole H1 is reduced, so that the resonance frequencies can be partially not aligned. Therefore, since the reflected wave from the frame 2 to the vibrating body 3a can also be disturbed, the sound pressure peak P at the resonance point can be varied to flatten the frequency characteristic of the sound pressure. That is, it is possible to obtain a favorable frequency characteristic of sound pressure.

  In FIG. 3C, the diaphragm 3 provided in the hole H1 is provided with a through hole, but the through hole is not necessarily provided.

  3D, the hole H1 may be a through hole having a deviation T. For example, although shown in a slightly exaggerated manner in FIG. 3D, when a through-hole is formed on the two frame bodies 2 using a drill or the like from the Z-axis direction, the range of tolerance is determined by the force applied by the drill or the like. In this case, a deviation T can occur.

  If the seam is exposed due to the deviation T, the hole H1 is originally a through hole, and in addition to forming a vibration wave in the cavity inside, the vibration in the cavity is further disturbed by the seam. be able to.

  As a result, the resonance frequencies can be partially unbalanced, so that the sound pressure peak P at the resonance point can be varied and the frequency characteristics of the sound pressure can be flattened. That is, it is possible to obtain a favorable frequency characteristic of sound pressure.

  Even if the hole H1 is formed with almost no deviation T, the seam itself by the two frames 2 is present, so that an effect of making the resonance frequencies partially not uniform can be obtained.

  Further, when the sound generator is fixed by inserting a screw or a bolt into the hole H1 after forming the hole H1, a gap is provided between the screw and the hole H1, so that the gap itself becomes the hole H1. Can produce the same effect.

  When the frame 2 is fixed to the housing with screws or bolts, the vibration concentrates in the vicinity of the hole H1 that is most fixed in the frame 2. At this time, by providing a gap between the screw and the hole H1, it is possible to resonate the concentrated vibration in the space of the gap, convert the vibration energy into heat energy, and reduce the sound pressure at the resonance frequency. The frequency characteristic of sound pressure can be flattened.

  Further, as shown in FIG. 3E as a hole H2, the “hole” may be a non-through hole. Thus, even if it is a non-through hole, since the hole H2 can disturb the vibration wave around it, the reflected wave from the frame body 2 to the vibration body 3a can also be disturbed, and the resonance frequency is partially increased. It can be made not to align. That is, the sound pressure peak P at the resonance point can be varied to obtain a favorable sound pressure frequency characteristic.

  Further, when the “hole” is formed as a non-through hole, as shown as holes H2 and H5 in FIG. 3F, for example, the directions of the holes face each other from the main surfaces of the two frames 2. It is good also as forming.

  In such a case, since the frame 2 can be thinned by the holes H2 and H5, the frame 2 can be easily deformed, and the vibration wave is disturbed so that the resonance frequencies are not partially aligned. Can help.

  Further, as shown in FIG. 3F, at this time, the bottoms of the holes H2 and H5 may have different shapes. For example, by using a drill for forming the hole H2 in FIG. 3F and using an end mill for forming the hole H5, the shape of each bottom can be made different.

  In this way, by making a difference in the shape of each “hole”, it is possible to give asymmetry to the overall shape of the composite vibrator including the “hole”, so that the vibration wave is disturbed and the resonance frequency is increased. It can help to make it partially unaligned.

  FIG. 3F illustrates the case where the holes H2 and H5 are formed so as to face each other. However, even if the holes H2 and H5 do not face each other, it is possible to obtain an effect that the resonance frequencies are not partially aligned. Needless to say.

  The above-described effects can be obtained in the same manner even when a groove is used instead of the hole.

  By the way, in the examples given so far, the case where the “hole” extends in the direction orthogonal to the main surface of the diaphragm 3 (see the Z-axis direction in the drawing) has been described. Such effects can be obtained.

  That is, in such a case, since the sound propagation direction generated by the sound generator 1 coincides with the axial direction of the “hole”, the vibration wave induced in the audio signal enters the “hole” and the “hole” It becomes easy to vibrate the "part".

  Therefore, the propagated vibration wave is likely to be disturbed around the “hole”, and accordingly, the resonance frequency can be partially unbalanced. That is, the sound pressure peak P at the resonance point can be varied to obtain a favorable sound pressure frequency characteristic.

  Of course, the axial direction of the “hole” is not limited to this. That is, as shown as holes H6 and H7 in FIG. 3G, the diaphragm 3 may be formed along the plane direction (refer to the XY plane direction in the drawing).

  Further, at this time, it may be formed as a through hole like the hole H6, or may be formed as a non-through hole like the hole H7.

  Further, although not shown, the direction (axial direction) in which the “hole” extends does not have to follow each axis of XYZ in the drawing. For example, the direction may be oblique with respect to each axis of XYZ. Moreover, the axial direction itself may change the direction in the middle.

  Furthermore, it is good also as a groove part instead of a hole part.

  By the way, up to now, the case where one “hole” is provided at each of the four corners of the frame 2 or the case where the outline of the “hole” when viewed in plan is substantially circular is taken as an example. Have been described (see, for example, FIG. 3A).

  However, the number and shape of the “holes” are not limited to the above examples. Therefore, other modifications will be described with reference to FIGS. 4A and 4B. FIG. 4A is a schematic plan view showing the configuration of the acoustic generator 1AA according to the first modification, and FIG. 4B is a schematic plan view showing the configuration of the acoustic generator 1AB according to the second modification. FIG.

  As shown in FIG. 4A, the sound generator 1AA according to the first modification example further includes a hole H8 in addition to the sound generator 1 (see FIG. 3A) according to the above-described embodiment.

  As shown in FIG. 4A, the hole H8 is provided at a portion that is not a corner of the frame body 2. For example, in FIG. 4A, the hole H8 is provided at a substantially central portion of the frame on the long side of the frame 2, but may be any part that is not a corner of the frame 2.

  By providing the hole H8 in this way, the symmetry as a composite vibrator can be reduced. Therefore, it is possible to contribute to making the resonance frequencies partially unbalanced. Therefore, it is possible to vary the sound pressure peak P at the resonance point and to easily obtain good sound pressure frequency characteristics.

  Moreover, compared with the case where the hole parts H1-H4 are provided only in the corner | angular part of the frame 2, it can make it easy to position by having the hole part H8. That is, it is possible to easily attach the sound generator 1AA.

  Moreover, the frame 2 as a support body has a plurality of holes extending in one direction, and the diameter of at least one of the plurality of holes may be different from the diameter of the other holes. . Specifically, as shown in FIG. 4A, when the hole H8 has the same depth as the corner holes H1 to H4, for example, the hole diameters of the corner holes H1 to H4 are different from each other. May be provided. Thereby, since the natural frequency of the hole H8 can be made different from that of the holes H1 to H4, it is possible to easily make the resonance frequencies partially unaligned. That is, the sound pressure peak P at the resonance point can also be varied to make it easy to obtain a favorable frequency characteristic of the sound pressure.

  Although not shown, the hole H8 may be provided with a difference in depth from the hole H1 to H4 at the corner when the hole has the same diameter as the hole H1 to H4 at the corner, for example. Although not shown, any one of the corner holes H1 to H4 (for example, the hole H1) has the same depth as the other holes (for example, the holes H2 to H4) and has a different diameter. Also good. Further, any one of the corner holes H1 to H4 (for example, the hole H1) may have the same diameter as the other holes (for example, the holes H2 to H4) and may have different depths.

  In the case where a plurality of holes are provided, the natural vibration caused by the volume of the hole can be made uneven by making only the depth or the diameter different, so that the sound pressure peak P at the resonance point is It is possible to make it easy to obtain a frequency characteristic with good sound pressure. In addition, in order to make the natural vibration due to the volume of the hole uneven, it is possible to suppress the generation of harmonic components by preventing the ratio of the depth and the aperture from becoming an integral multiple, which is favorable. The frequency characteristics of sound pressure can be easily obtained.

  Even if it is a case where it replaces with a several hole part and it is a some groove part, the above-mentioned effect is an effect acquired similarly, when width, depth, length, a shape, etc. differ.

  Further, as in the acoustic generator 1AB according to the second modified example shown in FIG. 4B, the outline of the “hole” may not be substantially perfect when viewed in plan. For example, the acoustic generator 1AB includes holes H2 'and H3' whose outlines when viewed in plan are substantially elliptical.

  In this way, the hole extends in one direction, and includes a “hole” so that the outline of the hole when it is cut in a direction perpendicular to one direction, including a substantially perfect circle and a substantially elliptic shape, forms a closed curve. Since the opening of the “hole” is easily deformed freely in response to the vibration wave propagating around the “hole”, it is possible to easily make the resonance frequency partially unaligned. . That is, also in such a case, the sound pressure peak P at the resonance point can be varied to make it easy to obtain good sound pressure frequency characteristics.

  Note that the case where the “hole” is viewed in plan includes the case where the “hole” is viewed in a cross section with respect to the axial direction. In other words, the shape may be formed to form a closed curve.

  In addition, until now, the frame 2 has a rectangular frame shape, and the inner region has a substantially rectangular shape as an example, and may be a polygon such as a regular n-gon. However, the shape according to the location in which an acoustic generator is mounted, and the design property requested | required may be comprised.

  Such a modification will be described with reference to FIG. FIG. 5 is a schematic plan view showing the configuration of an acoustic generator 1AC according to the third modification.

  As shown in FIG. 5, the frame body 2 may be formed such that the inner region has a shape with an R at the corner. Moreover, the outer periphery of the frame 2 may be provided such that the corners protrude outward, and the hole H9 may be formed in the protruding corners.

  Thus, even if the frame 2 has a unique shape according to the place to be mounted and the required design, the “hole” is provided in the frame 2 in the same manner as described above. By providing, it is possible to make the resonance frequencies not partially uniform. That is, the sound pressure peak P at the resonance point can be varied to obtain a favorable sound pressure frequency characteristic.

  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. .

  It goes without saying that the sound generators 1AA, 1AB, and 1AC shown in FIGS. 4A, 4B, and 5 can be mounted instead of the sound generator 1 shown in FIGS. 6A and 6B.

  As described above, the sound generator according to the embodiment includes an exciter (piezoelectric element), a vibrating body, and a support body (frame body). 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 support body supports the vibration body substantially flat. The support is provided with at least one hole.

  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, but 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.

  In the above-described embodiment, the case where the shape of the inner region of the frame is a substantially rectangular shape has been described as an example. However, the shape is not limited thereto, and may be a circle or an ellipse.

  In the above-described embodiment, the case where the resin layer is formed so as to cover the piezoelectric element and the vibrating body in the frame of the frame has been described as an example. However, such a resin layer is not necessarily formed.

  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. However, the present invention is not limited thereto, and may be configured by a plate-like member, for 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 ', 1AA, 1AB, 1AC 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 Resin layer 20 Sound generator 30, 40 Case 50 Electronic device 50a Controller 50b Transmission / reception part 50c Key input part 50d Microphone input part 50e Display part 50f Antenna 60 Electronic circuit C1, C2 Corner part H1-H9 Hole Part J Groove P Peak T Deviation re Vibration plate

Claims (11)

An exciter that vibrates upon receipt of an electrical signal;
The exciter is attached, and a diaphragm that vibrates with the exciter due to vibration of the exciter;
A support for supporting the diaphragm substantially flat,
The support body is composed of two frame members having substantially the same shape arranged so as to sandwich the outer peripheral portion of the diaphragm,
Sound generator, wherein the support one hole portions even without less is provided in, the hole portion is a through hole passing through the two frame members. An exciter that vibrates upon receipt of an electrical signal;
The exciter is attached, and a diaphragm that vibrates with the exciter due to vibration of the exciter;
A support for supporting the diaphragm substantially flat,
Wherein the support has at least one hole portion is provided, wherein the to Ruoto sound generator that has a part of the previous SL diaphragm inside the hole. An exciter that vibrates upon receipt of an electrical signal;
The exciter is attached, and a diaphragm that vibrates with the exciter due to vibration of the exciter;
A support for supporting the diaphragm substantially flat,
The support has a plurality of holes extending in one direction, and the diameter of at least one of the plurality of holes is different from the diameter of the other holes. It is Ruoto sound generator. The sound generator according to claim 2 , wherein the hole is a through-hole penetrating the support. The support body is a frame body provided at an outer peripheral portion of the main surface of the diaphragm and having at least one corner portion, and the hole portion is provided at the corner portion of the frame body. The sound generator according to any one of claims 1 to 4, wherein the sound generator is characterized in that: The hole has an acoustic generator according to any one of claims 1-5, characterized in that extending in a direction perpendicular to the main surface of the vibration plate. The said hole part is extended in one direction, The outline of the said hole part when cut | disconnected in the direction orthogonal to the said one direction is a closed curve, It is any one of Claims 1-6 characterized by the above-mentioned. Sound generator. The diaphragm, the acoustic generator according to any one of claims 1-7, characterized in that it consists of a resin film. The sound generator according to any one of claims 1 to 8 , wherein the exciter is a bimorph multilayer piezoelectric element. The sound generator according to any one of claims 1 to 9 ,
A sound generator comprising: a housing for housing 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 apparatus having a function of generating sound from the sound generator.

Images