TW201427440A - Sound generator, sound generating apparatus, and electronic apparatus - Google Patents

Abstract

To obtain excellent sound-pressure frequency characteristics. According to an embodiment of the present invention, a sound generator is provided with an exciter, a diaphragm, and a supporting body. The exciter vibrates when electric signals are inputted thereto. The diaphragm has the exciter attached thereto, and vibrates with the exciter due to the vibration of the exciter. The supporting body is provided on at least a part of an outer circumferential portion of the diaphragm, and supports the diaphragm. The diaphragm has different tensions respectively applied to a center portion thereof and other portions thereof.

Description

Sound generator, sound generator, and electronic machine

The disclosed embodiments relate to sound generators, sound generating devices, and electronic devices.

Conventionally, a sound generator using a piezoelectric element has been known (for example, refer to Patent Document 1). The sound generator applies a voltage to a piezoelectric element attached to the vibrating plate to vibrate, and thereby vibrates the vibrating plate to actively use the resonance of the vibration to output sound.

Further, since the diaphragm of the sound generator can use a film such as a resin film, it can be made thinner and lighter than a general electromagnetic speaker or the like.

Further, when a film is used in the vibrating plate, in order to obtain excellent sound conversion efficiency, it is necessary to hold the film from the thickness direction by, for example, a pair of frame members, and the film is supported under uniform tension.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-023436

However, the previous sound generator is positively Since the resonance of the diaphragm which is uniformly applied with tension is generated, it is easy to generate a peak (a portion where the sound pressure is higher than the surrounding portion) and a valley (a portion where the sound pressure is lower than the surrounding portion) in the frequency characteristic of the sound pressure, and thus it is difficult to obtain a good quality. The problem of sound quality.

One embodiment of the present invention is directed to the above-mentioned problems, and an object of the invention is to provide a sound generator, a sound generating device, and an electronic device that can obtain a frequency characteristic of a good sound pressure.

The sound generator according to one embodiment of the embodiment includes an exciter, a diaphragm, and a support. The exciter is vibrated by receiving an input of an electrical signal. The vibrating plate is mounted with the exciter, and vibrates together with the exciter by vibration of the vibrator. The support system is disposed on at least a portion of the outer circumference of the vibrating plate and supports the vibrating plate. Further, the vibrating plate applies a different tension to the other portion of the vibrating plate at the center portion.

According to one embodiment of the embodiment, the frequency characteristics of a good sound pressure can be obtained.

1, 1', 1AA‧‧‧ sound generator

2‧‧‧ frame

2a, 2b‧‧‧ frame components

2'‧‧‧Support

3‧‧‧vibration board

3a‧‧‧ vibrating body

5‧‧‧Piezoelectric components

5a, 5b, 5c, 5d‧‧‧ piezoelectric layers

5e‧‧‧Internal electrode layer

5f, 5g‧‧‧ surface electrode layer

5h, 5j‧‧‧ external electrodes

6a, 6b‧‧‧ wire

7‧‧‧ resin layer

20‧‧‧Sound generator

30, 40‧‧‧ cabinet

50‧‧‧Electronic machines

50a‧‧‧ controller

50b‧‧‧Send and Receive Department

50c‧‧‧Key input section

50d‧‧‧Microphone input

50e‧‧‧Display Department

50f‧‧‧Antenna

60‧‧‧Electronic circuits

L‧‧‧ axis

P‧‧‧ Peak

S‧‧‧ axis

C‧‧‧ gap

Fig. 1A is a plan view showing the schematic configuration of a basic sound generator.

Fig. 1B is a cross-sectional view taken along line A-A' of Fig. 1A (one).

Fig. 1C is a cross-sectional view taken along line A-A' of Fig. 1A (Part 2).

Fig. 1D is a plan view showing the central portion of the vibrating body.

Fig. 2 is a view showing an example of the frequency characteristics of the sound pressure.

Fig. 3A is a plan view (1) showing a configuration example of the sound generator of the embodiment.

Fig. 3B is a plan view (2) showing a configuration example of the sound generator of the embodiment.

Fig. 3C is a plan view (No. 3) showing a configuration example of the sound generator of the embodiment.

Fig. 4A is a plan view (1) showing an example of a case where tension is applied to a vibrating body from a plurality of directions.

Fig. 4B is a plan view (part 2) showing an example of a case where tension is applied to a vibrating body from a plurality of directions.

Fig. 4C is a plan view (3) of an example of a case where tension is applied to a vibrating body from a plurality of directions.

The fourth 4D is a plan view (fourth) of an example of a case where tension is applied to a vibrating body from a plurality of directions.

Fig. 4E is a plan view (fifth) showing an example of a case where tension is applied to a vibrating body from a plurality of directions.

Fig. 5A is a schematic view (1) showing an example of a method of making the tension of the vibrating body uneven.

Fig. 5B is a schematic view (2) showing an example of a method of making the tension of the vibrating body uneven.

Fig. 6A is a view showing the configuration of a sound generating device of the embodiment.

Fig. 6B is a view showing the configuration of an electronic device of the embodiment.

[Formation of the Invention]

Hereinafter, embodiments of the sound generator, the sound generating device, and the electronic device disclosed in the present invention will be described in detail with reference to the accompanying drawings. Further, the present invention is not limited by the embodiments shown below.

First, before explaining the sound generator 1 of the embodiment, the schematic configuration of the basic sound generator 1' will be described using Figs. 1A to 1D. Fig. 1A is a plan view schematically showing the schematic configuration of the sound generator 1', Fig. 1B is a cross-sectional view taken along line A-A' of Fig. 1A, and Fig. 1C is a line AA' of Fig. 1A In the cross-sectional view (2), the 1D drawing shows a plan view of the central portion of the vibrating body.

In addition, in order to make the description easy to understand, the three-dimensional orthogonal coordinate system including the Z-axis in which the vertical direction is the positive direction and the vertical direction is the negative direction is illustrated in FIGS. 1A to 1D. The orthogonal coordinate system is also shown in other drawings that are also used in the description below.

Moreover, in FIG. 1A, illustration of the resin layer 7 (described later) is omitted. Further, in order to make the description easy to understand, the first and second drawings show the sound generator 1' in an excessively exaggerated manner in the thickness direction (Z-axis direction).

As shown in Fig. 1A, the sound generator 1' includes a housing 2, a diaphragm 3, a piezoelectric element 5 as a vibration exciter, and wires 6a and 6b. Further, as shown in FIG. 1A, in the following description, the case where the piezoelectric element 5 is one is exemplified, but the number of the piezoelectric elements 5 is not limited.

Moreover, as shown in the example of FIG. 1B, the frame 2 functions as a support for supporting the diaphragm 3 at the outer peripheral portion (peripheral portion) of the diaphragm 3. The vibrating plate 3 has a plate shape or a film shape, and its peripheral portion is fixed to the frame 2 And being substantially flatly supported in a state in which tension is applied in the frame of the casing 2. Further, the frame 2 shown in Fig. 1B is composed of one frame member.

Further, in the example shown in FIG. 1C, the casing 2 is composed of two frame members 2a and 2b having a rectangular frame shape and having the same shape, and functions to sandwich the outer peripheral portion (peripheral portion) of the vibrating plate 3. And supporting the support of the vibrating plate 3. The vibrating plate 3 has a plate shape or a film shape, and the peripheral portion thereof is sandwiched and fixed to the frame body 2, and is supported in a substantially flat state in a state in which tension is applied in the frame of the frame body 2.

In this case, since the tension of the vibrating plate 3 can be stabilized by sandwiching the vibrating plate 3 by the two frame members 2a and 2b, it is possible to have durability in which the frequency characteristics of the sound generator 1' are not changed for a long period of time. And better.

In addition, a portion of the vibrating plate 3 that is further inside than the inner circumference of the casing 2, that is, a portion of the vibrating plate 3 that is not slid by the frame 2 and is free to vibrate, is used as the vibrating body 3a. That is, the vibrating body 3a forms a substantially rectangular portion in the frame of the casing 2.

Further, the diaphragm 3 can be formed using various materials such as resin or metal. For example, the vibrating plate 3 can be formed of a resin film such as polyethylene or polyimine having a thickness of 10 to 200 μm.

In addition, the thickness, material, and the like of the frame member constituting the frame 2 are not particularly limited, and may be formed using various materials such as metal or resin. For example, a stainless steel manufacturer having a thickness of 100 to 1000 μm can be suitably used as the frame member constituting the frame 2, for the reason that the mechanical strength and the corrosion resistance are excellent.

Further, in Fig. 1A, the frame 2 having a substantially rectangular shape in the inner region is shown, but a polygonal shape such as a parallelogram, a trapezoid, or a regular n-angle may be used. In the present embodiment, as shown in Fig. 1A, the shape is substantially rectangular.

The piezoelectric element 5 is provided on the surface of the vibrating body 3a via adhesion or the like, and is an exciter that vibrates the vibrating body 3a by generating vibration by application of a voltage.

The piezoelectric element 5 is as shown in FIG. 1B or FIG. 1C, and includes, for example, piezoelectric layers 5a, 5b, 5c, and 5d, which are composed of four layers of ceramics; and a laminated body composed of three layers of internal electrodes. The layers 5e are alternately laminated; the surface electrode layers 5f and 5g are formed on the upper surface and the lower surface of the laminate; and the external electrodes 5h and 5j are formed on the side surface of the internal electrode layer 5e. Further, the lead wires 6a and 6b are connected to the external electrodes 5h and 5j. The wires 6a, 6b are wires from which an electrical signal is input from the outside.

Further, the piezoelectric element 5 is formed in a plate shape, and a polygonal shape such as a rectangular shape or a square shape is formed on the main surface on the upper surface side and the lower surface side. Further, the piezoelectric layers 5a, 5b, 5c, and 5d are polarized as indicated by arrows in Fig. 1B or Fig. 1C. That is, the direction in which the polarization is polarized to the direction of the electric field applied at a certain moment is reversed in one side in the thickness direction (the Z-axis direction in the drawing) and the other side.

Further, when a voltage is applied to the piezoelectric element 5 via the wires 6a, 6b, for example, at a certain moment, the piezoelectric layers 5c, 5d which are bonded to the side of the vibrating body 3a are shrunk, and the piezoelectric element 5 is The piezoelectric layers 5a and 5b on the upper side are elongated. Therefore, by supplying an alternating current signal to the piezoelectric element 5, the piezoelectric element 5 performs bending vibration, and the vibrating body 3a can be bent. Curved vibration.

Further, the principal surface of the piezoelectric element 5 is bonded to the main surface of the vibrating body 3a by an adhesive such as epoxy resin.

Further, as the material constituting the piezoelectric layers 5a, 5b, 5c, and 5d, a non-lead piezoelectric material such as a lead zirconate titanate, a Bi layer compound, or a tungsten bronze structure compound can be used. Piezoelectric ceramics.

Further, various materials can be used for the material of the internal electrode layer 5e. For example, in the case of containing a metal component composed of silver and palladium and a ceramic component constituting the piezoelectric layers 5a, 5b, 5c, and 5d, the piezoelectric layer 5a, 5b, 5c, 5d and the internal electrode layer can be reduced. Since the stress caused by the difference in thermal expansion of 5e is obtained, the piezoelectric element 5 having no lamination failure can be obtained.

Further, as shown in FIG. 1B or FIG. 1C, the sound generator 1' further includes a resin layer 7, and the resin layer 7 is provided on the vibrating body 3a between the housing 2 and the piezoelectric element 5 (exciter). on. Specifically, the resin layer 7 is disposed in the frame of the casing 2 so as to cover the surfaces of the piezoelectric element 5 and the vibrating body 3a, and is integrated with the vibrating body 3a and the piezoelectric element 5.

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

In addition, FIG. 1B or FIG. 1C shows a state in which the resin layer 7 is formed at the same height as the casing 2, but it is only required to be filled in the frame of the casing 2. The piezoelectric element 5 may be filled, for example, the resin layer 7 may be formed to be higher than the height of the frame 2.

In this manner, the vibrating body 3a, the piezoelectric element 5, and the resin layer 7 are integrated to form a so-called composite vibrating body that integrally vibrates.

In addition, in the first FIG. 1 or FIG. 1C, an example of a bimorph type laminated piezoelectric element is exemplified as the piezoelectric element 5. However, the present invention is not limited thereto. For example, the stretched piezoelectric element 5 may be adhered to The unimorph type of the vibrating body 3a.

When the vibrating body 3a is substantially flatly supported in a state in which the tension is uniformly applied in the frame of the casing 2, peaks or valleys or deformation due to resonance induced by the vibration of the piezoelectric element 5 are generated, so that it is specified. The sound pressure in the frequency will change drastically, and the frequency characteristics of the sound pressure will be difficult to flatten.

This point is shown in Fig. 2, and Fig. 2 is a view showing an example of the frequency characteristics of the sound pressure. When the vibrating body 3a is substantially flatly supported in a state in which the tension is uniformly applied in the frame of the casing 2, the peaks are concentrated at a specific frequency and retracted due to the resonance of the vibrating body 3a, so as shown in Fig. 2, It is easy to produce steep peaks or valleys scattered throughout the frequency region.

For example, in Fig. 2, attention is paid to a portion surrounded and indicated by a closed curve PD of a broken line. In the case where such a peak occurs, since the sound pressure is uneven depending on the frequency, it is difficult to obtain good sound quality.

In this case, as shown in Fig. 2, the height of the peak P is lowered (see the arrow 201 in the figure), and the width of the peak is enlarged (see the arrow 202 in the figure), and the peak P or the valley is made ( Omitted illustration) Smaller countermeasures are effective of.

Therefore, in the present embodiment, the tension applied to the diaphragm 3 (the vibrating body 3a) is different from the other portions in the central portion of the diaphragm 3 (vibrating body 3a). In other words, by making the tension acting on the diaphragm 3 (the vibrating body 3a) asymmetrical, the symmetry of the vibrating body 3a and the entire composite vibrating body as described above is lowered.

Thereby, by making the resonance frequencies partially inconsistent, the resonance mode is decomposed and dispersed, and the height of the peak P is lowered, and the width of the peak is enlarged.

In addition, the tension in the central portion of the vibrating plate 3 (vibrating body 3a) is, for example, 0.2 to 100 gf/mm, and the tension in the other portions is, for example, 0.24 to 400 gf/mm, and the difference in the tension is, for example, 1.2 times. ~4 times is effective.

Here, the "central portion" when the tension is different from the other portions in the central portion of the vibrating plate 3 (the vibrating body 3a) is at least a part of the region overlapping the piezoelectric element 5 in plan view as shown in FIG. 1D. . Generally, the "central portion" of the vibrating body 3a means the position of the center of gravity when viewed from the plane.

In the center portion, as shown in FIGS. 3A and 3B, when the tension is reduced along the axis L or the axis S, the tension is maximized at other portions except for the center portion. In other words, in the central portion of the diaphragm 3 (vibrating body 3a), the tension system is minimized, and the portion having the largest tension is located at a portion other than the center portion. In other words, since the tension acting on the vibrating body 3a can be made asymmetrical, the resonance frequencies are partially inconsistent, and the frequency characteristics of the sound pressure can be flattened.

Further, as a measurement method of the above tension, for example, The tension meter can be measured after it has been pressed against the measurement site. In other words, the tension is measured by pressing the tension gauge between the center portion of the vibrating plate 3 (vibrating body 3a) and other portions, and the tension may be different from the tension at the center portion.

When the tension of the vibrating body 3a is measured, for example, the tension meter is pressed against the surface of the vibrating body 3a on the side where the piezoelectric element 5 is not provided, and the value indicated by the tensiometer is measured to confirm whether or not the value is a different value. Here, it is preferable to measure the center of the region overlapping the piezoelectric element 5 in plan view as shown in Fig. 1D and the vicinity of the outer periphery.

Further, the resin layer 7 may be dissolved by an organic solvent or the like as needed, or the piezoelectric element 5 may be peeled off.

Hereinafter, the sound generator 1 of the embodiment will be specifically described using Figs. 3A and 3B. 3A and 3B are schematic plan views (1) and (2) showing a configuration example of the sound generator 1 of the embodiment.

In addition, in the drawings shown below, for convenience of explanation, the illustration of the resin layer 7 may be omitted as in the case of FIG. 1A.

Further, in each of the following figures, the magnitude of the tension acting on the vibrating body 3a is distinguished by the thick blank arrow and the thin black arrow, and the thick blank arrow indicates that the tension is larger than that of the thin black arrow (see 3A, 3B)). Again, the direction of these arrows indicates the direction in which the tension is applied.

In addition, in order to facilitate the following description, the central axis of the vibrating body 3a along the longitudinal direction is referred to as "axis L", and the central axis of the vibrating body 3a along the width direction is referred to as "axis S".

In contrast to the sound generator 1', the vibrating body 3a of the sound generator 1 of the embodiment is attached to the center portion and the other portion of the vibrating body 3a. The tension is different. Here, the tension may be applied from at least one direction (here, the longitudinal direction) as shown in FIG. 3A.

By applying tension from at least one direction in this manner, tension in other directions is liable to differ. In other words, since the tension acting on the vibrating body 3a tends to be asymmetrical, the resonance frequencies are partially inconsistent, and the peak P of the sound pressure at the resonance point is made uneven, which contributes to flattening the frequency characteristics of the sound pressure.

Moreover, in the case where the vibrating body 3a is formed by applying tension only from one direction, compared with the case where tension is applied from a plurality of directions, labor and time are not required, and an effect of mass production can be obtained.

Further, as shown in FIG. 3A, the tension of the vibrating body 3a may be set to be uneven in the same direction. In other words, the tension acting on the portion on the "axis L" which is the central axis of the vibrating body 3a along the longitudinal direction, and the tension acting on the portion parallel to the axis L and away from the axis L become uneven. . For example, in Fig. 3A, the case where the tension along the axis L is small is shown. In the case of FIG. 3A, the tension in the region where the piezoelectric element 5 exists in the longitudinal direction of the vibrating body 3a (that is, the oblique line region in the drawing) is at least smaller than the other portions.

In Fig. 3A, the case of the longitudinal direction of one direction is explained, but as shown in Fig. 3B, one direction may also be the width direction. In the case of the third FIG. 3B, the tension in the region where the piezoelectric element 5 exists in the width direction of the vibrating body 3a (that is, the oblique line region in the drawing) is at least smaller than the other portions.

Therefore, since the tension acting on the vibrating body 3a is still asymmetrical because of this, the resonance frequencies are locally inconsistent, The peak P of the sound pressure at the resonance point is made uneven, and the frequency characteristic of the sound pressure can be flattened. That is, the frequency characteristics of a good sound pressure can be obtained.

Further, in the case of Fig. 3A, an example in which the tension is large and the tension is small is described. However, as shown in Fig. 3C, there may be more portions having different tensions.

Although the description will be made later using the fourth embodiment, the tension of the vibrating body 3a may be applied not only in one direction but also in other directions intersecting the one direction. Of course, it may be applied in two directions orthogonal to the longitudinal direction shown in FIGS. 3A and 3C and the width direction shown in FIG. 3B. In this case, although the tension is not uniform, at least the rigidity of the vibrating body 3a can be maintained.

Next, a case where tension is applied to the vibrating body 3a from a plurality of directions will be described using FIGS. 4A to 4E. 4A to 4E are plan views (1) to (5) of an example of a case where tension is applied to the vibrating body 3a from a plurality of directions. Further, here, the plurality of directions are two directions orthogonal to each other in the longitudinal direction and the width direction.

As shown in Fig. 4A, even if the tension applied to the vibrating body 3a is applied from the longitudinal direction and the width direction, the tension along the axis L and the axis S can be made relatively small. The tension acting on the central portion of the vibrating body 3a becomes small. Also in this case, since the tension acting on the vibrating body 3a can be made asymmetrical, the resonance frequencies can be made partially inconsistent.

Further, as shown in Fig. 4B, the tension can be uniformly applied in the width direction and uneven in the longitudinal direction. In this case, in addition to making the tension acting on the vibrating body 3a asymmetrical, the width is also made. The tension of the direction becomes relatively large, whereby the sound generator 1 which easily emits a low frequency region can be obtained.

Further, contrary to the case of Fig. 4B, as shown in Fig. 4C, the tension may be uniformly applied in the longitudinal direction and uneven in the width direction. In this case, in addition to making the tension acting on the vibrating body 3a asymmetrical, the tension in the longitudinal direction is relatively large, whereby it is possible to prevent the piezoelectric element 5 from being out of control due to vibration and suppressing sound distortion. effect.

Further, as shown in Fig. 4D, the tension can be made non-uniform in both the longitudinal direction and the width direction, and the resonance frequency can be partially made inconsistent, and the frequency characteristic of the sound pressure can be effectively flattened.

In this case, since the tension acting on the vibrating body 3a can be made more asymmetrical, the resonance frequencies can be partially inconsistent, and the frequency characteristics of the sound pressure can be effectively flattened.

Further, the tension of the central portion of the vibrating body 3a has been relatively small compared to other portions, but as shown in Fig. 4E, the tension at the central portion of the vibrating body 3a can be made larger than other portions. .

Also in this case, since the tension acting on the vibrating body 3a can be made asymmetrical, the resonance frequencies are locally inconsistent, and the frequency characteristics of the sound pressure can be flattened.

Next, an example of a method of making the tension of the vibrating body 3a uneven will be described using FIGS. 5A and 5B. FIGS. 5A and 5B are schematic views (1) and (2) showing an example of a method of making the tension of the vibrating body 3a uneven.

Further, in Fig. 5B, a sound generator 1AA which is a modified example in which the vibrating body 3a is supported at both ends in the longitudinal direction by the support 2' of the housing 2 is exemplified.

For example, when the vibrating body 3a having the largest tension at a portion other than the center portion is desired, as shown in FIG. 5A, the piezoelectric element 5 can be mounted in a state where no tension is applied to the vibrating body 3a. The vibrating body 3a is applied to the vibrating body 3a at a later time.

Further, as shown in the sound generator 1AA shown in FIG. 5B, in the case where the vibrating body 3a is supported by the support 2' from both ends in the longitudinal direction, by forming the notch c in the support 2', it is possible to The uniformity of the vibrating body 3a imparts a change, that is, becomes uneven.

Here, the support 2' is supported by the vibrating body 3a from both ends in the longitudinal direction. However, the present invention is not limited thereto, and for example, it may be supported only at both ends in the width direction of the vibrating body 3a. In other words, the support system including the housing 2 may be provided on at least a part of the outer peripheral portion of the vibrating body 3a.

Next, the sound generating device and the electronic device of the sound generator 1 of the present embodiment described so far will be described using Figs. 6A and 6B. Fig. 6A is a view showing a configuration of the sound generating device 20 of the embodiment, and Fig. 6B is a view showing a configuration of the electronic device 50 of the embodiment. In addition, in the both figures, only the constituent elements required for explanation are shown, and the description about the general constituent elements is omitted.

The sound generating device 20 is a so-called speaker sounding device, as shown in FIG. 6A, and includes, for example, a sound generator 1, and a casing 30 that houses the sound generator 1. The box 30 is made by the sound generator 1 The sound resonates inside, and the sound is radiated from an opening (not shown) formed in the casing 30 to the outside. By having such a casing 30, for example, the sound pressure in the low frequency band can be improved.

Further, the sound generator 1 can be mounted on various electronic devices 50. For example, in Fig. 6B, which is shown next, the electronic device 50 is a portable terminal device such as a mobile phone or a tablet terminal.

As shown in FIG. 6B, the electronic device 50 is provided with an electronic circuit 60. The electronic circuit 60 is composed of, 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 a sound signal to the sound generator 1. The sound generator 1 generates sound based on a sound signal input from the electronic circuit 60.

Further, the electronic device 50 includes a display unit 50e, an antenna 50f, and a sound generator 1. Moreover, the electronic device 50 is provided with the case 40 which accommodates each of these components.

In addition, in FIG. 6B, each of the components including the controller 50a is housed in a single housing 40, but it is not intended to limit the storage state of each component. In the present embodiment, at least the electronic circuit 60 and the sound generator 1 may be housed in one case 40.

The controller 50a is a control unit of the electronic device 50. The transmission/reception unit 50b transmits and receives data or the like via the antenna 50f under the control of the controller 50a.

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

The display unit 50e is a display output unit of the electronic device 50, and outputs display information in accordance with the control of the controller 50a.

Further, the sound generator 1 operates as a sound output unit of the electronic device 50. Further, the sound generator 1 is connected to the controller 50a of the electronic circuit 60, and receives a voltage controlled by the controller 50a to emit a sound.

In the sixth embodiment, the electronic device 50 is described as a portable terminal device. However, regardless of the type of the electronic device 50, it can be applied to various consumer devices having a sound generating function. For example, a thin-type television or a car audio device can be used for a product having a function of emitting a "speaking" sound, for example, a vacuum cleaner or a washing machine, a refrigerator, a microwave oven, or the like.

As described above, the sound generator of the embodiment includes the vibration exciter (piezoelectric element), the vibrating body, and the support. The exciter receives an input of an electrical signal and vibrates. The vibration system is equipped with the vibration exciter and vibrates together with the vibration exciter by the vibration of the vibration exciter. The support system is provided on at least a part of the outer peripheral portion of the vibrating body, and supports the vibrating body substantially flat. Further, in the vibration system, different tensions are applied to the center portion of the vibrating body and other portions.

Therefore, according to the sound generator of the embodiment, the frequency characteristics of a good sound pressure can be obtained.

In the above-described embodiment, the piezoelectric element is mainly provided on one main surface of the vibrating body. However, the piezoelectric element is not limited thereto, and the piezoelectric element may be provided on both sides of the vibrating body.

Further, in the above-described embodiment, the resin layer is formed by covering the piezoelectric element and the vibrating body in the frame of the casing. However, the resin layer may not necessarily be formed.

In the above-described embodiment, the exciter is a piezoelectric element. However, the exciter is not limited to a piezoelectric element, and may be a function that vibrates by inputting an electrical signal.

For example, it may be an electrodynamic vibration exciter, an electrostatic exciter, or an electromagnetic exciter that is known as an exciter that vibrates a speaker.

In addition, the electrodynamic exciter causes a current to flow to a coil disposed between the magnetic poles of the permanent magnet to vibrate the coil, and the electrostatic exciter causes a bias voltage and an electrical signal to flow to the opposite two metal plates. When the metal plate is vibrated, the electromagnetic exciter causes an electrical signal to flow to the coil to vibrate the thin iron plate.

Further effects or modifications can be readily derived by those of ordinary skill in the art to which the invention pertains. Therefore, the broad aspects of the present invention are not limited to the specific details and representative embodiments described above. Therefore, various modifications may be made without departing from the spirit and scope of the inventions of the invention.

1‧‧‧Sound generator

2‧‧‧ frame

3a‧‧‧ vibrating body

5‧‧‧Piezoelectric components

L‧‧‧ axis

Claims (11)

A sound generator, comprising: an exciter that vibrates by receiving an input of an electrical signal; and a vibrating plate mounted with the exciter, the vibration exciter being coupled to the exciter And the support body is disposed at least a part of the outer peripheral portion of the vibrating plate and supports the vibrating plate; the vibrating plate applies a different tension to the other portions of the vibrating plate at the central portion. The sound generator of claim 1, wherein the tension is uneven between a portion on the central axis in the same direction and a portion on the axis away from the central axis. The sound generator of claim 1, wherein the tension is minimal in the central portion of the vibrating plate. A sound generator according to claim 1, wherein the tension is applied from at least one of the vibrating plates. A sound generator according to claim 4, wherein the tension is applied from the one direction of the vibrating plate and the other direction. The sound generator of claim 5, wherein the other direction is an orthogonal direction of the one direction of the plane view. A sound generator according to claim 1, wherein the vibrating plate is composed of a resin film. A sound generator according to claim 1, wherein the vibration exciter is a bimorph type piezoelectric element. The sound generator of claim 1, wherein the support system is disposed on a frame of the outer periphery of the vibrating plate, and further comprises a resin disposed on the vibrating plate between the frame and the exciter Floor. A sound generating device, comprising: a sound generator according to any one of claims 1 to 9; and a casing for accommodating the sound generator. An electronic machine, comprising: a sound generator according to any one of claims 1 to 9; an electronic circuit connected to the sound generator; and a box for housing the electronic circuit and the sound generator Body; has the function of generating sound from the sound generator.