JP5714190B2 - 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, it is known that an acoustic generator typified by a piezoelectric speaker can be used as a small and thin speaker. Such a sound generator can be used as a speaker incorporated in an electronic device such as a mobile phone or a thin television.

  As the sound generator, for example, there is one including a rectangular frame, a film stretched on the frame, and a piezoelectric vibration element provided on the film (see Patent Document 1). This is a structure in which a film whose outer edge is supported by a frame is excited and sounded using the resonance phenomenon of the film.

Japanese Patent Laid-Open No. 2004-23436

  However, since the above-described conventional sound generator actively uses the resonance of the diaphragm, the frequency characteristics of the sound pressure have a peak (a portion where the sound pressure is higher than the surroundings) and a dip (the sound pressure is higher than the surroundings). There is a problem that it is difficult to obtain a high-quality sound quality.

  In addition, the sound generator and the electronic device provided with the sound generator also have a problem that it is difficult to obtain good sound quality.

  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 in accordance with aspects of the embodiment includes a diaphragm, a fixed frame member on the outer periphery of the main surface of the vibrating plate, and a exciter which is provided on a main surface of the vibration plate, The frame is fixed on the outer peripheral portion of the main surface of the diaphragm over the entire circumference , and when the frame is cut along a plane perpendicular to the main surface of the diaphragm, the width of the frame Has a portion that is non-uniform in the thickness direction.

  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 embodiment of the present invention, it is possible to realize an acoustic generator, an acoustic generator, and an electronic apparatus that can obtain a frequency characteristic with good sound quality.

FIG. 1 is a schematic plan view of an embodiment of an acoustic generator. 2A is a cross-sectional view showing an example cut along the line A-A ′ of FIG. 1, and FIG. 2B is a schematic enlarged view of a broken line region shown in FIG. 3A is a cross-sectional view showing another example cut along the line A-A ′ of FIG. 1, and FIG. 3B is a schematic enlarged view of a broken line region shown in FIG. 4A is a cross-sectional view showing another example cut along the line A-A ′ of FIG. 1, and FIG. 4B is a schematic enlarged view of a broken line region shown in FIG. FIG. 5A and FIG. 5B are schematic plan views of other examples of the frame shown in FIG. FIG. 6 is a schematic plan view of another example of the frame shown in FIG. FIG. 7 is a block diagram of the sound generator. FIG. 8 is a block diagram of an electronic device.

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

  The configuration of the acoustic generator according to this embodiment will be described with reference to FIGS. 1 and 2.

  The acoustic generator 1 according to the present embodiment is a so-called piezoelectric speaker, and has a configuration for generating sound pressure using a resonance phenomenon of a diaphragm. Specifically, as shown in FIGS. 1 and 2, the sound generator 1 includes a frame body 10, a diaphragm 20 fixed to the frame body 10, and an exciter provided on the diaphragm 20. As a piezoelectric vibration element 30. And when the frame 10 is cut | disconnected by the surface perpendicular | vertical with respect to the main surface of the diaphragm 20, it has the site | part where the width | variety of the frame 10 is non-uniform | heterogenous in the thickness direction.

  1 is a schematic plan view of an embodiment of the acoustic generator, FIG. 2A is a cross-sectional view showing an example cut along the line AA ′ in FIG. 1, and FIG. 2B. FIG. 3 is a schematic enlarged view of a broken line area shown in FIG. In FIG. 2, in order to facilitate understanding, the sound generator 1 is shown expanded and deformed in the vertical direction.

  The diaphragm 20 can be formed using various materials such as resin, metal, and paper. For example, the thin diaphragm 20 can be formed of a resin film such as polyethylene, polyimide, or polypropylene having a thickness of 10 to 200 μm. Since the resin film is a material having a lower elastic modulus and mechanical Q value than a metal plate or the like, the diaphragm 20 is made of a resin film, so that the diaphragm 20 bends and vibrates with a large amplitude, thereby reducing the sound pressure. It is possible to reduce the difference between the resonance peak and the dip by widening the width of the resonance peak and reducing the height in the frequency characteristics. A composite of metal and resin may be used as the diaphragm 20.

  The frame 10 plays a role of holding the diaphragm 20 and forming a fixed end of vibration. For example, as shown in FIG. 2, the frame 10 is comprised by the upper frame member 10-1 and the lower frame member 10-2. And the outer peripheral part of the diaphragm 20 which consists of a resin film is pinched | interposed between the upper frame member 10-1 and the lower frame member 10-2, and it fixes in the state which provided predetermined tension. Therefore, the acoustic generator 1 having the diaphragm 20 with less deformation such as deflection even when used for a long time is obtained.

  The thickness and material of the upper frame member 10-1 and the lower frame member 10-2 constituting the frame body 10 are, for example, a stainless steel material having a thickness of 100 to 5000 μm because it is excellent in mechanical strength and corrosion resistance. Can be used. However, the material of the frame 10 is not limited to stainless steel, and glass, resin, or the like can also be used.

  The piezoelectric vibration element 30 as an exciter is formed on the side surface where the laminated body 33, the surface electrode layers 34 and 35 formed on the upper and lower surfaces of the laminated body 33, and the end face of the internal electrode layer 32 of the laminated body 33 are exposed. The formed external electrodes 36 and 37 are provided. Lead terminals 38 and 39 are connected to the external electrodes 36 and 37.

  The laminate 33 is formed by alternately laminating four piezoelectric layers 31a, 31b, 31c, 31d made of ceramics and three internal electrode layers 32. The piezoelectric vibration element 30 has a rectangular main surface on the upper surface side and the lower surface side, and the piezoelectric layers 31a and 31b and the piezoelectric layers 31c and 31d are polarized in different directions in the thickness direction, respectively. The piezoelectric layers 31b and 31c are polarized in the same direction.

  Therefore, when a voltage is applied to the piezoelectric vibration element 30 via the lead terminals 38 and 39, for example, the piezoelectric layers 31c and 31d on the lower surface side of the piezoelectric vibration element 30, in other words, the vibration plate 20 side shrink, while the upper surface The piezoelectric layers 31a and 31b on the side are deformed so as to extend. As described above, the piezoelectric layers 31a and 31b on the upper surface side of the piezoelectric vibration element 30 and the piezoelectric layers 31c and 31d on the lower surface side exhibit opposite expansion and contraction behavior, and as a result, the piezoelectric vibration element 30 is bent by a bimorph type. By vibrating, the diaphragm 20 can be given a certain vibration to generate a sound.

  As described above, the piezoelectric vibration element 30 is a bimorph-type laminated piezoelectric vibration element, and the piezoelectric vibration element 30 itself bends and vibrates independently. For example, the piezoelectric vibration element 30 is a soft vibration plate 20 regardless of the material of the vibration plate 20. However, strong vibrations can be generated, and a sufficient sound pressure can be obtained with a small number of piezoelectric vibration elements 30.

  Here, as a material constituting the piezoelectric layers 31a, 31b, 31c, 31d, conventionally used are lead-free piezoelectric materials such as lead zirconate titanate, Bi layered compounds, and tungsten bronze structure compounds. Piezoelectric ceramics can be used. The material of the internal electrode layer 32 is mainly composed of a metal such as silver and palladium. The internal electrode layer 32 may contain ceramic components constituting the piezoelectric layers 31a, 31b, 31c, and 31d, whereby the piezoelectric layers 31a, 31b, 31c, and 31d and the internal electrode layers 32 and 32 are included. , 32 can be obtained, and the piezoelectric vibration element 30 in which the stress due to the difference in thermal expansion is reduced.

  The surface electrode layers 34 and 35 and the external electrodes 36 and 37 are mainly composed of a metal such as silver. Moreover, you may contain a glass component. By containing the glass component, it is possible to obtain a strong adhesion between the piezoelectric layers 31a, 31b, 31c, 31d and the internal electrode layer 32 and the surface electrode layers 34, 35 or the external electrodes 36, 37. . The glass component content may be, for example, 20% by volume or less.

  Further, as the wiring connected to the lead terminals 38 and 39, in order to reduce the height of the piezoelectric vibration element 30, it is preferable to use a flexible wiring in which a metal foil such as copper or aluminum is sandwiched between resin films.

  Further, as shown in FIG. 2, the acoustic generator 1 according to the present embodiment includes a resin coating layer 40 filled in the frame body 10 so as to embed the piezoelectric vibration element 30. Thus, by embedding the piezoelectric vibration element 30 with the resin coating layer 40, it is possible to induce an appropriate damping effect, suppress the resonance phenomenon, and further reduce the difference between the resonance peak and the dip. be able to. Further, the piezoelectric vibration element 30 can be protected from the external environment.

  In the present embodiment, the entire surface of the diaphragm 20 is covered with the coating layer 40, but it is not necessary to cover the entire surface. That is, the acoustic generator 1 only needs to cover at least a part of the surface of the piezoelectric vibration element 30 and the vibration plate 20 on the side where the piezoelectric vibration element 30 is disposed with the coating layer 40.

In the sound generator 1 according to the present embodiment, as shown in FIG. 2, when the frame body 10 is cut along a plane perpendicular to the main surface of the diaphragm 20, the width of the frame body 10 is in the thickness direction. It has a portion that is non-uniform.
Specifically, FIG. 2 shows a configuration in which a concave portion or a convex portion is provided on the inner wall 11 of the frame body 10, and the width of the frame body 10 in the direction parallel to the main surface of the diaphragm 20 is thick. It has a portion that is non-uniform in direction.

  As a result, the frame body 10 has a shape with reduced symmetry as compared with a conventional frame body in which the width of the diaphragm 20 is uniform in the thickness direction. By reducing the symmetry of the frame body 10, the symmetry of the composite vibration body constituted by the frame body 10, the diaphragm 20, the piezoelectric vibration element 30 and the coating layer 40 is lowered. It can be distributed in a plurality of vibration modes.

  Therefore, according to the acoustic generator 1 according to the present embodiment, it is possible to reduce the peak level of the resonance frequency and obtain a favorable sound pressure frequency characteristic with small fluctuation.

  Further, since the concave portion 11 a or the convex portion 11 b is provided on the inner wall 11 of the frame body 10, the vibration of the frame body 10 is disturbed by the irregular shape of the inner wall 11 and is difficult to transmit to the diaphragm 20 and the covering layer 40. The peak or dip level in the frequency characteristic of the sound pressure due to the vibration of the frame 10 can be reduced.

Such a concave portion 11a or convex portion 11b may be provided at any position on the inner wall 11 of the frame body 10, but when the frame body 10 has at least one corner portion 13 on the inside when viewed in plan, By being provided at the corner portion 13 of the frame body 10, even if the vibration waves are diffracted and overlapped, the phase of the overlapping vibration waves does not coincide with each other and it is difficult to resonate.
In particular, the concave portion 11 a or the convex portion 11 b may be provided over the entire circumference of the inner wall 11, whereby the vibration transmitted from the frame body 10 to the diaphragm 20 or the covering layer 40 can be further reduced.

  Further, by providing the convex portion 11b on the inner wall 11 of the frame 10 so as to be in contact with the diaphragm 20, the vibration wave of the diaphragm 20 collides with the convex portion 11b and diffracts, so that resonance can be suppressed. Furthermore, when the convex portion 11b is formed over the entire circumference along the frame body 10, when an audio signal propagates from the vibration region of the diaphragm 20 to the opening portion of the frame body 10, the opening area after passing through the convex portion 11b. However, since the signal wave is spread with a step, the signal wave is disturbed and hardly resonates, and it is possible to achieve an effect that it is not reflected clearly.

  In addition, as an example in which the width of the frame 10 has a portion that is not uniform in the thickness direction, for example, as illustrated in FIG. 3, the inner wall 11 of the frame 10 is inclined toward the diaphragm 20. A form is also mentioned. Specifically, in the form shown in FIG. 3, the inner walls 11 of the upper frame member 10-1 and the lower frame member 10-2 constituting the frame body 10 both incline toward the diaphragm 20 side (inner side) and vibrate. As the plate 20 is approached, the widths of the upper frame member 10-1 and the lower frame member 10-2 are narrowed.

  In such a case as well, as in the example shown in FIG. 2, the vibration of the frame body 10 is disturbed by the shape of the inner wall 11 and is difficult to be transmitted to the diaphragm 20 and the covering layer 40. The peak or dip level in the frequency characteristic of sound pressure can be reduced.

  Such an inclination may be provided at any position on the inner wall 11 of the frame body 10. However, when the frame body 10 has at least one corner portion 13 on the inside when viewed in plan, the corner of the frame body 10 may be provided. By being provided in the portion 13, even if the vibration waves are diffracted and overlapped, it is possible to achieve an effect that the phases of the overlapped vibration waves do not coincide with each other and do not resonate and are not clearly reflected.

  In particular, by inclining the inner wall 11 over the entire circumference, when an audio signal propagates from the vibration region of the diaphragm 20 to the opening of the frame body 10, the signal area at the opening end is disturbed by the change in the opening area. Therefore, it is difficult to resonate, and it is possible to achieve an effect that the reflection is not beautiful.

  In order to provide the concave portion 11a or the convex portion 11b on the inner wall 11 of the frame body 10 (the upper frame member 10-1 and the lower frame member 10-2) or to incline the inner wall 11, for example, Examples of the method include punching using a mold having a shape, forming by etching, and pouring into a mold and hardening, but there is no particular limitation.

  When the frame body 10 is one of the upper frame member 10-1 or the lower frame member 10-2, the inner wall 11 of the frame body 10 is inclined so that the width of the frame body 10 becomes wider as it approaches the diaphragm 20. In this form, the rigidity of the frame is reduced at the opening of the frame, so that the opening is easily distorted when the sound is loud, the signal wave at the end of the opening is disturbed, hardly resonates, and does not reflect cleanly. The effect can be achieved.

  On the other hand, when the frame body 10 is one of the upper frame member 10-1 or the lower frame member 10-2, the inner wall 11 of the frame body 10 is inclined so that the width of the frame body 10 becomes narrower as it approaches the diaphragm 20. In this embodiment, since the rigidity of the frame is increased at the opening of the frame, the sound generator having a high sound pressure can be obtained without deformation of the opening even when the sound is increased.

Moreover, in the case where the frame body 10 is two pieces of the upper frame member 10-1 and the lower frame member 10-2,
In the form in which the inner walls of the upper frame member 10-1 and the lower frame member 10-2 are inclined so that the width becomes narrower as approaching the diaphragm 20 as shown in FIG. 3, a vibration region of the diaphragm 20 is secured. However, since the sound signal generated on the front and back surfaces from the diaphragm 20 toward the opening of the frame body 10 can be reflected again on the diaphragm 20, the effect of disturbing the vibration wave near the end of the opening. Is produced, and it is difficult to resonate.

  On the other hand, in the case where there are two frame bodies 10, that is, the upper frame member 10-1 and the lower frame member 10-2, as shown in FIG. -1 and the inner wall of the lower frame member 10-2 may be inclined. According to this embodiment, since the opening width on the side opposite to the diaphragm 20 can be made larger than the opening width on the diaphragm 20 side, the lowest resonance frequency can be widened to the low sound side. At this time, since the vibration wave at the resonance point can be disturbed by the inclination, the sound pressure at the lowest resonance frequency can be suppressed, so that the output sound pressure of the lower frequency than the lowest resonance frequency can be improved. It can be set as a wide acoustic apparatus.

  Note that the inner wall has a shape in which the inner wall is inclined so that the width increases as the upper frame member 10-1 approaches the diaphragm 20, and the inner wall such that the width decreases as the lower frame member 10-2 approaches the diaphragm 20. The shape may be inclined, and even if each has the opposite shape, it can be adopted.

  Moreover, although the example in the case where the inclined inner wall 11 is formed in a straight line shape in a sectional view is shown, the inclined inner wall 11 may have a concave portion 11a or a convex portion 11b as shown in FIG.

  Furthermore, in addition to the above-described configuration, the frame 10 may be formed with a non-uniform width between the inner wall 11 and the outer wall 12, for example, when the main surface of the diaphragm 20 is viewed in plan view, Of the inner periphery and the outer periphery, the shape of the inner periphery may be a shape with low symmetry. This point will be described with reference to FIGS.

  As shown in FIG. 5A, the inner periphery of the frame 10 has a shape having a plurality of (here, two) diagonals L1 and L2 when the diaphragm 20 is viewed in plan view. Of the diagonal lines L1 and L2, at least two diagonal lines L1 and L2 are configured to have different lengths. Thereby, the inner periphery of the frame 10 has a shape having no symmetry such as rotational symmetry or mirror symmetry.

  That is, the outer periphery of the diaphragm 20 made of a resin film is held and fixed by the frame body 10 having no symmetry such as rotational symmetry or mirror symmetry, and the lengths of the two diagonal lines L1 and L2 are different. The acoustic generator 1 includes the diaphragm 20 having a quadrangular planar shape that does not have a rotationally symmetric point or a line-symmetric axis of symmetry.

  As described above, the acoustic generator 1 according to the present embodiment is configured so that the planar shape of the inner periphery of the frame body 10 is a quadrangular shape in which the lengths of at least two diagonal lines are different from each other. The planar shape of the diaphragm 20 to be fixed is also a quadrangular shape in which at least two diagonal lines have different lengths. Thereby, it is possible to obtain the diaphragm 20 having no symmetry such as rotational symmetry or mirror symmetry, or having reduced symmetry. By breaking the structural symmetry of the diaphragm 20 in this way, the degenerated vibration modes are dispersed into a plurality of vibration modes, a plurality of resonance peaks are generated, and the sound quality is further improved by flattening the sound pressure. Can do.

  That is, by reducing the symmetry of the planar shape of the inner periphery of the frame 10, the symmetry of the composite vibration body constituted by the frame 10, the diaphragm 20, the piezoelectric vibration element 30 and the coating layer 40 is further reduced. Therefore, the sound quality can be improved more effectively.

  Further, as shown in FIG. 5A, the inner periphery of the frame 10 is formed such that the midpoint D1 of the diagonal L1 and the midpoint D2 of the diagonal L2 do not coincide with each other. Thus, by arranging the midpoints D1 and D2 of the plurality of diagonal lines L1 and L2 at positions where they do not overlap each other, antinodes of vibration waves transmitted along the respective diagonal lines L1 and L2 are difficult to overlap. This makes it difficult for strong resonance to occur at a specific frequency, so that the difference between the resonance peak and the dip in the frequency characteristic of sound pressure can be reduced.

  Further, as shown in FIG. 5B, the outer periphery of the frame body 10 also has a shape having a plurality of (here, two) diagonal lines L3 and L4 when the diaphragm 20 is viewed in plan view. Is formed such that the intersection C2 between the outer diagonal lines L3 and L4 and the intersection C1 between the inner diagonal lines L1 and L2 do not coincide with each other. In this way, by arranging the intersection C2 between the outer diagonal lines L3 and L4 and the intersection C1 between the inner diagonal lines L1 and L2 at positions where they do not overlap each other, the amplitude of the natural vibration of the frame 10 is reduced. Can do. That is, the vibration of the frame body 10 accompanying the diaphragm 20 can be further suppressed.

  On the other hand, like the frame 10 shown in FIG. 6, the inner peripheral surface 11 surrounded by the inner wall 11 is formed into a rectangular shape, and the outer peripheral planar shape surrounded by the outer wall 12 is formed into a shape having low symmetry. The width between the outer wall 12 and the outer wall 12 may be formed non-uniformly.

  Even in such a case, since the symmetry of the frame body 10 can be reduced, the symmetry of the composite vibration body constituted by the frame body 10B, the diaphragm 20, the piezoelectric vibration element 30, and the covering layer 40 is lowered. . Thereby, the degeneration of the vibration mode can be solved and dispersed in a plurality of vibration modes.

  Furthermore, the width between the inner wall 11 and the outer wall 12 is formed nonuniformly by making both the planar shape of the inner periphery surrounded by the inner wall 11 and the planar shape of the outer periphery surrounded by the outer wall 12 low in symmetry. May be. By comprising in this way, the symmetry of the frame 10 can further be reduced.

  As described above, according to the acoustic generator according to the present embodiment and each modification, the difference between the resonance peak and the dip in the frequency characteristic of the sound pressure is reduced, and the frequency fluctuation is suppressed as much as possible. Therefore, sound quality can be improved.

  Next, a sound generator equipped with the sound generator 1 according to this embodiment will be described with reference to FIG. FIG. 7 is a block diagram of the sound generator.

  As shown in FIG. 7, the sound generator 4 can be configured by housing the sound generator 1 having the above-described configuration in a resonance box 400. The resonance box 400 is a housing that houses the sound generator 1, and resonates the sound emitted from the sound generator 1 and radiates it as sound waves from the housing surface. Such a sound generator 4 can be used alone as a speaker, and can be suitably incorporated into various electronic devices 2, for example.

  As described above, since the difference between the resonance peak and the dip in the frequency characteristic of sound pressure, which is disadvantageous in the piezoelectric speaker, can be reduced, the sound generator 1 according to the present embodiment can be used for a mobile phone or a thin television. Alternatively, it can be suitably incorporated into the electronic device 2 such as a tablet terminal.

  Note that the electronic device 2 to which the sound generator 1 can be incorporated is not limited to the above-described mobile phone, flat-screen TV, tablet terminal, and the like, and for example, a refrigerator, a microwave oven, a vacuum cleaner, a washing machine, and the like. Conventionally, home appliances that have not been focused on sound quality are also included.

  Here, the electronic device 2 including the above-described sound generator 1 will be briefly described with reference to FIG. FIG. 8 is a block diagram of the electronic device 2. The electronic device 2 includes the acoustic generator 1 described above, an electronic circuit connected to the acoustic generator 1, and a housing 200 that houses the acoustic generator 1 and the electronic circuit.

  Specifically, as shown in FIG. 8, the electronic device 2 includes an acoustic generator 1, an electronic circuit including a control circuit 21, a signal processing circuit 22, and a radio circuit 23 as an input device, an antenna 24, and these And a housing 200 for storing the. Although the wireless input device is shown in FIG. 8, it can be provided as a signal input by normal electric wiring.

  In addition, description was abbreviate | omitted here about the other electronic members (for example, devices and circuits, such as a display, a microphone, a speaker) with which the electronic device 2 is provided. In FIG. 8, one acoustic generator 1 is illustrated, but two or more acoustic generators 1 and other oscillators may be provided.

  The control circuit 21 controls the entire electronic device 2 including the wireless circuit 23 via the signal processing circuit 22. An output signal to the sound generator 1 is input from the signal processing circuit 22. Then, the control circuit 21 generates a sound signal S by controlling the signal processing circuit 22 from the signal input to the radio circuit 23 and outputs the sound signal S to the sound generator 1.

  In this way, the electronic device 2 shown in FIG. 8 incorporates the small and thin sound generator 1 and reduces the difference between the resonance peak and the dip as much as possible to suppress the frequency fluctuation as much as possible. It is possible to improve the sound quality as a whole even in a high sound region including a low sound region having a low sound level.

  8 exemplifies the electronic device 2 in which the sound generator 1 is directly mounted as the sound output device. However, as the sound output device, for example, the sound generator 4 in which the sound generator 1 is housed in the housing is mounted. It may be the configuration.

  Moreover, it is good also as improving the sound quality further by providing the diaphragm of the sound generator which concerns on this embodiment and each modification with the sheet-like damping material formed in appropriate shape and length. The damping material can be formed of a rubber material such as urethane rubber, for example.

  Further, in the acoustic generator described above, an example in which one piezoelectric vibration element is disposed on the diaphragm is illustrated, but two or more piezoelectric vibration elements may be disposed on the diaphragm. Further, although the piezoelectric vibration element is rectangular in plan view, it may be square.

  In the present embodiment and each modification, a so-called bimorph type stacked piezoelectric vibration element is exemplified as the piezoelectric vibration element. However, a unimorph type piezoelectric vibration element can also be used.

  In the present embodiment and each modification, the case where a piezoelectric vibration element is used as an example of an exciter has been described as an example. However, the exciter is not limited to a piezoelectric vibration element, and an electric signal is input. It is sufficient if it has a function of being vibrated. 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. 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.

DESCRIPTION OF SYMBOLS 1 Sound generator 2 Electronic device 4 Sound generator 10 Frame 11 Inner wall 11a Concave part 11b Convex part 12 Outer wall 20 Diaphragm 30 Piezoelectric vibration element 40 Covering layer

Claims (9)

A diaphragm, a frame body fixed on the outer periphery of the main surface of the vibrating plate, and a exciter provided on the major surface of the diaphragm, the frame body of the diaphragm over the entire periphery is fixed on the outer periphery of the main surface, when cutting the frame body in a plane perpendicular to the major surface of the diaphragm, the width of the frame is made uneven in the thickness direction A sound generator characterized by having a part.   The frame body includes an upper frame member and a lower frame member, and an outer peripheral portion of a main surface of the diaphragm is the upper frame member. Each of the upper frame member and the lower frame member. It has the site | part where the width | variety is non-uniform | heterogenous in the thickness direction. Sound generator. Sound generator according to claim 1 or claim 2, characterized in that there are recesses or protrusions on the inner wall of the frame. The sound generator according to any one of claims 1 to 3 , wherein an inner wall of the frame body is inclined toward the diaphragm. 2. The frame according to claim 1, wherein the frame has at least one corner when viewed in a plan view, and the portion having the non-uniform width is at least at the corner of the frame. Item 5. The acoustic generator according to any one of Items 4 to 5 . The acoustic generator according to any one of claims 1 to 5 , wherein a portion where the width of the frame body is non-uniform extends over the entire circumference of the frame body. The acoustic generator according to any one of claims 1 to 6 , wherein a width between the inner wall and the outer wall is non-uniform when viewed in a plan view. An acoustic generator comprising: the acoustic generator according to any one of claims 1 to 7 ; and a housing that accommodates the acoustic generator. An acoustic generator according to any one of claims 1 to 7 , an electronic circuit connected to the acoustic generator, and a housing that houses the electronic circuit and the acoustic generator. An electronic device having a function of generating sound from the sound generator.

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