JP2652600B2 - Electroacoustic transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electro-acoustic transducer such as an electromagnetic electro-acoustic transducer and a piezo-type electro-acoustic transducer.
In particular, the present invention relates to a device that stabilizes a resonance frequency (f ₀ ) by controlling a spring characteristic of a diaphragm used therein and improves reproducibility of output following an input.

[0002]

2. Description of the Related Art For example, an electromagnetic electroacoustic transducer is shown in FIG.
0. First, there is a case 1, and a base 3 is installed in the case 1 at a lower portion in the drawing. At the center position of the base 3, an iron core 5
Is attached. A bobbin 7 is attached to the outside of the iron core 5. A magnet wire 9 is wound around the bobbin 7. Terminals 11 and 13 are attached to the bobbin 7.
Reference numeral 3 extends and is arranged below in the figure. A plastic magnet 15 is provided inside the case 1 at an outer peripheral position of the bobbin 7. A potting agent 17 is applied to the lower surface of the base 3 so that the potting agent 17 enhances the sealing performance.

An elastic plate 19 is arranged in the case 1 at a position facing the iron core 5. The elastic plate 19 is attracted to the plastic magnet 15.
A magnetic piece 2 as an additional mass is provided at the center of the elastic plate 19.
1 is attached. The elastic plate 19 and the magnetic piece 21 constitute a diaphragm 20. The main purpose of attaching the magnetic piece 21 as the additional mass is to increase the mass to reduce the frequency of the output sound. Note that a through hole 23 is provided at the center of the upper part of the case 1 in the figure. A liquid-proof label 25 is arranged outside the through hole 23.

The elastic plate 19 and the magnetic piece 21 have a structure as shown in FIGS. 31 and 32. That is, both the elastic plate 19 and the magnetic piece 21 have a disc shape,
Is located at the center of the elastic plate 1 by spot welding.
9 is fixed. In FIG. 31, the welding / fixing portion is denoted by reference numeral 27.
Indicated by The line indicated by reference numeral 29 in FIG.
Is a discrimination mark provided so that both sides can be discriminated and distinguished. That is, one surface of the elastic plate 19 is a sagging surface having an R-shaped edge, and the other surface is a burring surface with burrs at the edge. The magnetic piece 21 is mounted on the burrs. Line 29 above
Is provided for discriminating between the sagging surface and the burring surface.

In the above configuration, the elastic plate 19 is in a state of being attracted and attracted to the plastic magnet 15, and is thereby set with a certain magnetic pole. When a current is applied to the coil via the terminals 11 and 13 in this state, the iron core 5 is turned into an electromagnet, and a magnetic field is generated at its tip. At this time, if the magnetic field generated by the coil generated in the iron core 5 and the magnetic pole generated by the magnet of the elastic plate 19 have different polarities, the elastic plate is attracted to the iron core 5. Conversely, when the magnetic field generated by the coil generated in the iron core 5 and the magnetic pole formed by the magnet of the elastic plate 19 have the same polarity, the elastic plate 19 repels the iron core 5. Therefore, by causing the current to flow intermittently in any direction, the elastic plate 19 repeats the above operation, and vibrates at a predetermined frequency. Sound is generated by the vibration.

[0006]

According to the above-mentioned conventional configuration, there are the following problems. That is, according to the conventional configuration, there is a problem that the resonance frequency (f ₀ ) is not stable in some cases, and the reproducibility of tracking the output with respect to the input is poor.
That is, the compliance of the diaphragm 20 (the reciprocal of the spring constant, which indicates the spring characteristic of itself) is
Compliance of the portion not in contact with the magnetic piece 21
It is determined by the state of the contact portion between the elastic plate 19 and the outer edge of the magnetic piece 21 and the portion supporting the elastic plate 19 (in the case of the above configuration, the structure of attraction / adsorption by the plastic magnet 15). Also, in the elastic plate 19, tension is generated around the outer edge of the magnetic piece 21 and around the support of the outer edge that is attracted and attracted by the plastic magnet 15 due to the attraction of the magnet.
The compliance is small.

[0007] Then, by the action already described,
When the diaphragm 20 is vibrated, the plastic magnet 1
If the fixing force of the outer peripheral portion of the diaphragm by the suction / suction by 5 is sufficient, the tension increases with an increase in amplitude (increase in applied voltage), and as a result, compliance decreases. That is, the spring constant of the diaphragm 20 gradually increases. Therefore, as shown in FIG. 33, the resonance frequency (f ₀ ) increases with an increase in the amplitude, and the spring characteristics of the diaphragm 20 show those of the hardened spring system. On the other hand, the plastic magnet 15
When the fixing force of the outer peripheral portion of the diaphragm due to the suction / suction is weak, the following state occurs. That is, as the amplitude increases, the above-mentioned suction / suction force is small.
9, the outer peripheral portion of which is the plastic magnet 15
It starts moving further away. Thereby, the tension decreases and the compliance temporarily increases. Thereafter, as the amplitude further increases, the tension increases, thereby reducing the increased compliance. This is shown in FIG. That is, the resonance frequency (f ₀ ) once decreases and then increases. In any of the above cases, there is a region where the resonance frequency (f ₀ ) changes with the change in the amplitude (FIGS. 33 and 3).
4). In that area, the reproducibility of tracking the output with respect to the input deteriorates. Therefore, when the electromagnetic electro-acoustic transducer having such a configuration is used for amplitude modulation sound (AM sound) or attenuation sound, a desired sound pressure or tone cannot be reproduced with respect to an input. There is a problem that an area is generated.

[0008] Such a problem can be similarly applied not only to the electromagnetic electro-acoustic transducer but also to the piezo electro-acoustic transducer. That is, even in the case of a piezo-type electroacoustic transducer, an additional mass may be attached to a piezo element or an elastic plate in order to increase the frequency by adding mass, and in that case, the peripheral portion of the additional mass may be attached. And the compliance around the support part decreases with increasing amplitude,
The same problem as in the case of the electromagnetic electroacoustic transducer occurs.

Prior arts proposed to solve the above problems include Japanese Utility Model Application Publication No. 51-43807 (Reference 1) and Japanese Utility Model Application Publication No. 51-43808 (Reference 2). And Japanese Patent Application Publication No. 60-220397 (Reference 3). In Reference 1 and Reference 2, the additional mass is a laminate of thin films, giving elasticity to the outer edge of the additional mass,
This is an example of suppressing a change in compliance when the amplitude changes. However, in this case, there is a drawback that the compliance of the vibration system greatly varies due to dew condensation, freezing, and rust. In Reference 3, the surface in contact with the elastic body of the additional mass is a curved surface that matches the curvature of the elastic body in the suction support state, so that the rise of (f ₀ ) during the suction support is suppressed, and the compliance at the time of amplitude change is improved. This is an example of suppressing the change. However, in this case, there is a problem that it is difficult to design a curved surface having an additional mass and manage mass production.

The present invention has been made based on such a point, and an object of the present invention is to control the fluctuation of the spring characteristic with respect to the amplitude of the diaphragm to suppress the fluctuation of the resonance frequency (f ₀ ). It is an object of the present invention to provide an electro-acoustic transducer capable of improving the follow-up reproducibility of an output with respect to an input.

[0011]

In order to achieve the above object, an electroacoustic transducer according to the present invention includes a diaphragm having an elastic plate and an additional mass fixed to a central portion of the elastic plate. In the electroacoustic transducer, the additional mass includes a contact portion that directly contacts the elastic plate, and the contact portion is non-circular and, assuming a circle that connects its outer peripheral portion, the inside of the circle. The elastic plate has a shape capable of providing a portion allowing deformation of the elastic plate.

In this case, the additional mass is composed of a main body and a projection protruding from the main body toward the elastic plate, and the projection has a flat surface that comes into contact with the elastic body. Function as a contact portion, and the protrusions are extended and expanded in a radial direction at a plurality of locations, and provide portions that allow deformation of the elastic body between the respective extended and expanded portions. It is possible to do. Further, the additional mass has a flat surface that comes into contact with the elastic plate, the flat surface functions as a contact portion, and the additional mass is extended and expanded in a radial direction at a plurality of locations,
It is conceivable to provide a portion allowing deformation of the elastic plate between the respective extension / deployment portions.

It is desirable that the outer edge of the flat surface is formed in an arc shape with an appropriate radius of curvature. or,
It is conceivable that the main body has a shape similar to the shape of the projection. Further, the extension / deployment length of the flat surface in the radial direction is a size that is inscribed in, or slightly smaller than, the “node circle” of the resonance mode of the natural resonance frequency of the diaphragm. Is preferred. In addition, as an electroacoustic transducer, a case of an electromagnetic electroacoustic transducer and a case of a piezo electroacoustic transducer can be considered.

[0014]

According to the present invention, in an electromagnetic electroacoustic transducer provided with a diaphragm having an elastic plate and an additional mass fixed to the center of the elastic plate, the additional mass is A contact portion that directly contacts the elastic plate is provided, and the contact portion is non-circular, and assuming a circle that connects the outer peripheral portions, a portion that allows the deformation of the elastic plate is provided inside the circle. It has a shape that can be provided. Therefore, assuming that the contact portion is a circle connecting the outer peripheral portions, a deformable elastic plate portion can be obtained inside the circle. In other words, it is possible to realize a configuration in which springs having different spring characteristics are connected to the outside and inside of the circle, thereby suppressing and stabilizing fluctuations in the resonance frequency (f ₀ ) due to changes in amplitude. Can be. Therefore, the reproducibility of tracking the output with respect to the input is improved, and it is possible to sufficiently cope with the case where the output is used for the AM sound or the attenuation sound.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. This embodiment shows an example in which the present invention is applied to an electromagnetic electroacoustic transducer. In the case of the electromagnetic electroacoustic transducer according to this embodiment, the configuration of the diaphragm 101 is improved. The vibration plate 101 includes an elastic plate 103 made of a metal having a thin film disk shape and having magnetism, and a magnetic piece 105 as an additional mass attached to the elastic plate 103. The magnetic piece 105 is made of a metal having magnetism. As shown in FIGS. 4 and 5, the magnetic piece 105 includes a disk-shaped magnetic piece main body 107 and a projection 109 protruding from the magnetic piece main body 107 toward the elastic plate 103.

The protrusions 109 are arranged concentrically with respect to the magnetic piece main body 107 and have a shape extending radially in a direction of 120 ° by a predetermined amount. The surface 111 of the projection 109 on the elastic plate 103 side is a flat surface, and the surface 11
1 comes into contact with the elastic plate 103. The size of the projection 109 (extended length in the radial direction) is a size that is inscribed in the resonance mode “node circle” of the natural resonance frequency of the diaphragm 101, or more. It is desirable that they are slightly smaller. Here, the above-mentioned "segment circle" will be described. That is, assuming a vibration system as shown in FIG. 6, it is assumed that there is a resonance mode having a natural resonance frequency of the diaphragm 101, which is as shown in FIG. In this case, a circle indicated by a virtual line in the figure is a “knot circle”. Also, depending on the vibration system, a plurality of “knot circles” may occur concentrically, but in this case, it means the innermost circle. If the length of the projection 109 in the radial direction is extended to the outside of such a “knot circle”, the resonance mode of the natural resonance frequency of the diaphragm 101 may be mischievously hindered. Because it becomes.

The outer edge of the flat surface 111 of the projection 109 is preferably formed in an arc shape with an appropriate radius of curvature. This is because if the outer edge is an edge during the repetition of the vibration, stress concentrates on the edge and the reliability is reduced. By forming an arc with an appropriate radius of curvature, such stress is reduced. This is to prevent concentration. As shown in FIG. 3, the magnetic piece 105 is fixed to the elastic plate 103 by spot welding at a position corresponding to the projection 109 extended in the radial direction or at the center of the projection 109. In the drawing, the welded portion is indicated by reference numeral 113.

The operation will be described based on the above configuration. The basic operation of the electromagnetic electro-acoustic transducer for outputting a predetermined sound in response to an input is the same as in the related art, and a description thereof will be omitted. When the vibration plate 101 vibrates, a portion where the magnetic piece 105 having a sufficient thickness is in contact with the elastic plate 103 has a high rigidity of the contact portion, and thus the portion is hardly deformed. Become. That is, the diaphragm 10
The one deformable region is limited to the outer peripheral portion of the contact portion with the magnetic piece 105. Considering the above points, in the conventional case, the magnetic piece is formed in a disk shape, and when the vibration plate 101 vibrates, the magnetic piece contacts the elastic plate 103 in the entire disk-shaped portion. Therefore, the deformable region of the diaphragm 101 is only the outer portion of the circle. On the other hand, in the case of this embodiment, the magnetic piece 10
5 is the elastic plate 103 via only the surface 111 of the projection 109.
Therefore, there is a deformable elastic plate portion between the respective extensions extending in the radial direction of the projection 109, that is, in the region inside the circle. That is, in the region outside the circle, there is a region that can be deformed as before, and at the same time, there is a deformable elastic plate portion also in the region inside the circle.

Here, when the deformable elastic plate portion in the region inside the circle is compared with the conventional deformable elastic plate portion in the region outside the circle, the manner in which the tension is applied and the magnetic piece are different. It is considered that the deformation is suppressed by the protrusion 109 of 105, so that the compliance is smaller than that of the outer region and has different spring characteristics. Further, since the members are the same elastic plate 103, it is considered that the spring is continuous. That is,
In other words, the configuration is such that different springs having different spring characteristics are connected. At that time, the compliance changes continuously from the outer region to the inner region of the circle. Even in the case where the diaphragm having the additional mass vibrates as in the case of the present invention, when the amplitude increases, similarly to the case of the conventional circular additional mass, the tension increases around the additional mass and around the support portion (see FIG. Compliance). However, the tension generated around the additional mass does not reach the outside of the circle circumscribing the protrusion 109 of the additional mass, which is a nodal circle of the resonance mode of vibration, due to the deformation of the elastic plate 103 in the circle. Therefore, the tension generated around the additional mass due to the vibration causes the elastic plate 10 outside the nodal circle in the resonance mode.
The change in the resonance frequency (f ₀ ) with respect to the change in the amplitude can be suppressed to be stable until the compliance of No. 3 is affected.

According to this embodiment, the following effects can be obtained. First, the magnetic piece 105 is provided with a projection 109 extending in the radial direction, and is configured to contact the elastic plate 103 via the surface 111 of the projection 109.
It is possible to obtain a deformable elastic plate portion even inside the articulated circle, whereby the resonance frequency (f
₀ ) can be suppressed and stabilized. Therefore, the reproducibility of tracking the output with respect to the input is improved, and it is possible to sufficiently cope with the case where the output is used for the AM sound or the attenuation sound. FIG. 7 shows an experimental result showing that the fluctuation of the resonance frequency (f ₀ ) due to the change in the amplitude was suppressed and stabilized. As shown in FIG. 7, it can be seen that the resonance frequency (f ₀ ) is stable even when the amplitude changes (changes in applied voltage, 1 V, 3 V, 5 V, 7 V). FIG. 8 shows the applied voltage characteristics at that time.

The fact that the resonance frequency (f ₀ ) is stable with respect to the fluctuation of the amplitude means that the resonance frequency (f ₀ ) is stable against various fluctuations (variations in parts itself, fluctuations in assembly, etc.) which cause fluctuations in the amplitude. This also means that the resonance frequency (f ₀ ) is stable, so that even if there is some variation in the parts themselves or in assembly, the characteristics of the finished product will have little variation. To explain this more specifically, first, there are variations in coil winding and variations in material as variations in components themselves, and variations in coil winding affect variations in inductance and resistance. . Further, the variation in the material affects the variation in thickness and the variation in spring characteristics. Next, variations in assembly include variations in processing, that is, warpage due to pressing and dimensional change due to caulking. Even if the amplitude fluctuates due to these various variations, the resonance frequency (f
₀ ) can be stabilized. Furthermore, since the contact area of the magnetic piece 105 with the elastic plate 103 is reduced, entry of foreign matter into the gap between them is reduced, and the fluctuation of the characteristics due to the foreign matter is also reduced.

The present invention is not limited to the above embodiment. First, in the case of the above embodiment, the elastic plate 1
Although both the magnetic piece 03 and the magnetic piece 105 are made of a metal having magnetism, it is also conceivable that only one of them is made of a metal having magnetism. For example, when the elastic plate 103 is made of a metal having magnetism,
May be constituted by something like hard rubber. The projections 109 on the magnetic piece 105 may be, for example, those shown in FIGS. 9 to 17 in addition to those shown in the above-described embodiment. That is, the spring characteristics can be changed by changing the number of the protrusions 109 or changing the shape of the protrusions 109.
In addition, by changing the projection 109, the frictional resistance generated on the contact surface 111 also changes, so that the spring characteristics can be changed.

Also, as shown in FIGS. 18 and 20, the shape of the magnetic piece main body 107 may be a shape similar to the shape of the projection 109. Also, as shown in FIGS. 19 and 21, the magnetic piece 105 may be the projection 109 itself as long as the weight and the center of gravity of the whole magnetic piece 105 can be made the same. In other words, the magnetic piece 105 is constituted only by the protrusion 109 without the disk-shaped magnetic piece main body 107. These are effective in the case where the lateral movement and the amplitude of the magnetic piece 105 are large and the outer edge of the magnetic piece main body 107 is likely to come into contact with the elastic plate 103.
Further, as shown in FIGS. 22 and 23, the protrusion 109 may be formed by projecting a portion other than the protrusion 109 from the magnetic piece main body 107 to a side opposite to a contact surface with the elastic plate 103. Further, as shown in FIG. 24 to FIG. 27, the projection 109 may have a shape in which a portion on the opposite side of the contact surface is concave.

The present invention can be applied not only to an electromagnetic electro-acoustic transducer but also to a piezo electro-acoustic transducer. It is shown in FIG. First, there is a case 201,
In this case 201, a diaphragm 203 having an outer peripheral portion fixed with an adhesive 204 or the like is provided. The vibration plate 203 includes an elastic plate 205 and a piezo element 207 attached to the elastic plate 205. An additional mass 209 having a diaphragm structure according to the present invention is attached to the elastic plate 205 on the side opposite to the piezo element 207. The additional mass 209 has a shape similar to that of the magnetic piece 105 in the embodiment. However, in this case, there is no need to use a magnetic piece.
It has become. With this configuration, as in the case of the first embodiment, the spring characteristics of the vibration plate 203 can be controlled to suppress and stabilize the fluctuation of the resonance frequency (f ₀ ) due to the change in amplitude. .

FIG. 29 shows another example in which the present invention is applied to a piezo-type electroacoustic transducer. In this case, an additional mass 209 is attached to the piezo element 207. In this case, the same effect as that shown in FIG. 28 can be obtained. Although not shown, in the case of a piezo-type electro-acoustic transducer, the piezo element 207 itself may have the same shape as the additional mass 209. In this case, the piezo element 207 functions not only as the original function of the piezo element 207 but also as an additional mass. By controlling the spring characteristics, fluctuations in the resonance frequency (f ₀ ) due to changes in the amplitude can be suppressed and stabilized.

[0026]

As described in detail above, according to the electro-acoustic transducer according to the present invention, the additional mass has a contact portion which comes into contact with the elastic plate, and the contact portion forms a circle connecting the outer peripheral portions thereof. Assuming that the shape is such that it can provide a portion allowing deformation of the elastic plate inside the circle, the contact portion assumes a circle connecting its outer periphery, A deformable elastic plate portion can be obtained inside the circle. In other words, it is possible to realize a configuration in which springs having different spring characteristics are connected to the outside and inside of the circle, thereby suppressing and stabilizing fluctuations in the resonance frequency (f ₀ ) due to changes in amplitude. Can be. Therefore, the reproducibility of tracking the output with respect to the input is improved, and it is possible to sufficiently cope with the case where the output is used for the AM sound or the attenuation sound.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the present invention, and is a plan view of a diaphragm.

FIG. 2 is a view showing one embodiment of the present invention, and is a side view of the diaphragm.

FIG. 3 is a plan view of the diaphragm showing a welded portion of the magnetic piece in the view showing one embodiment of the present invention.

FIG. 4 is a view showing one embodiment of the present invention, and is a plan view of a magnetic piece viewed from a projection side.

FIG. 5 is a side view of a magnetic piece according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating an embodiment of the present invention and is a diagram for explaining a knot circle.

FIG. 7 is a diagram showing an example of the present invention, and is a characteristic diagram showing a change in resonance frequency (f ₀ ) with respect to a change in amplitude.

FIG. 8 is a diagram illustrating an example of the present invention, and is a characteristic diagram illustrating characteristics of an applied voltage.

FIG. 9 is a view showing another embodiment of the present invention, and is a plan view of the magnetic piece viewed from the projection side.

FIG. 10 is a view showing another embodiment of the present invention, and is a plan view of the magnetic piece viewed from the projection side.

FIG. 11 is a view showing another embodiment of the present invention, and is a plan view of the magnetic piece viewed from the projection side.

FIG. 12 is a view showing another embodiment of the present invention, and is a plan view of a magnetic piece viewed from a projection side.

FIG. 13 is a view showing another embodiment of the present invention, and is a plan view of a magnetic piece viewed from a projection side.

FIG. 14 is a view showing another embodiment of the present invention, and is a plan view of the magnetic piece viewed from the protrusion side.

FIG. 15 is a plan view of another embodiment of the present invention, in which the magnetic piece is viewed from the protrusion side.

FIG. 16 is a view showing another embodiment of the present invention, and is a plan view of the magnetic piece viewed from the projection side.

FIG. 17 is a view showing another embodiment of the present invention, and is a plan view of a magnetic piece viewed from a projection side.

FIG. 18 is a view showing another embodiment of the present invention, and is a plan view of the magnetic piece viewed from the projection side.

FIG. 19 is a view showing another embodiment of the present invention, and is a plan view of a magnetic piece composed of only protrusions.

FIG. 20 is a view showing another embodiment of the present invention, and is a plan view of the magnetic piece viewed from the projection side.

FIG. 21 is a view showing another embodiment of the present invention, and is a plan view of a magnetic piece composed of only protrusions.

FIG. 22 is a view showing another embodiment of the present invention, and is a plan view of the magnetic piece viewed from the projection side.

FIG. 23 is a perspective view of the magnetic piece shown in FIG. 22, showing another embodiment of the present invention.

FIG. 24 is a perspective view of another embodiment of the present invention, in which the magnetic piece is viewed from the side opposite to the protrusion.

FIG. 25 is a view showing another embodiment of the present invention, and is a perspective view of the magnetic piece viewed from the side opposite to the protrusion.

FIG. 26 is a view showing another embodiment of the present invention, and is a perspective view of the magnetic piece viewed from the side opposite to the protrusion.

FIG. 27 is a view showing another embodiment of the present invention, and is a perspective view of the magnetic piece viewed from the side opposite to the protrusion.

FIG. 28 is a view showing another embodiment of the present invention, and is a cross-sectional view showing an example in which the present invention is applied to a piezo-type electroacoustic transducer.

FIG. 29 is a view showing another embodiment of the present invention, and is a cross-sectional view showing an example in which the present invention is applied to a piezo-type electroacoustic transducer.

FIG. 30 is a view showing a conventional example, and is a cross-sectional view of an electromagnetic electroacoustic transducer.

FIG. 31 is a view showing a conventional example and a plan view of a diaphragm.

FIG. 32 is a side view of the diaphragm in the conventional example.

FIG. 33 is a diagram showing a conventional example, and is a characteristic diagram showing a change in resonance frequency (f ₀ ) with respect to a change in amplitude.

FIG. 34 is a diagram showing a conventional example, and is a characteristic diagram showing a change in resonance frequency (f ₀ ) with respect to a change in amplitude.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Vibration plate 103 Elastic plate 105 Magnetic piece 107 Magnetic piece main body 109 Projection 111 Flat surface

Claims (8)

(57) [Claims] And 1. A resilient plate, and additional mass fixed to the central portion of the elastic plate, the electric-acoustic transducer having a diaphragm provided with the contact the added mass is in direct contact with the elastic plate The contact portion has a non-circular shape and a shape that can provide a portion allowing deformation of the elastic plate inside the circle, assuming a circle connecting the outer peripheral portions thereof. air transducer collector, characterized in that it it. 2. The method of claim 1 electric-acoustic transducer, wherein the additional mass is composed of a main body, a projection projecting from the elastic plate side of said body, said projection is in contact with the elastic plate have a flat surface serves as a flat surface contact portion of the projection, also the projection has been extended, expanded in the radial direction at a plurality of locations, each of the extension-expansion <br/> unit inter air transducer collector, characterized in that there is provided a portion that allows deformation of the elastic plate. 3. The electro-acoustic transducer according to claim 1, wherein the additional mass has a flat surface that contacts the elastic plate, the flat surface functions as a contact portion, and the additional mass. Electro-acoustic transducers characterized by> extending radially at a plurality of locations and providing portions allowing deformation of the elastic plate between the respective extending / developing portions. . 4. The electroacoustic transducer according to claim 2, wherein an outer edge of the flat surface is formed in an arc shape with an appropriate radius of curvature. 5. The electric-acoustic transducer of claim 2, wherein the body care transducer electricity, characterized in that a shape approximate to the shape of the projection. 6. The electroacoustic transducer according to claim 2, wherein the extension / deployment length of the flat surface in the radial direction is a “knot circle” of a resonance mode of a natural resonance frequency of the diaphragm. An electroacoustic transducer having a size inscribed in or slightly smaller than the size. 7. The method of claim 1 or claim 2 or claim 3 or claim 4 or claim 5 or claim 6 electrical acoustic transducer according electro-acoustic transducer is an electromagnetic type electroacoustic transducer air transducer collector, characterized in that. 8. The method of claim 1 or claim 2 or claim 3 or claim 4 or claim 5 or claim 6 electrical acoustic transducer according electro-acoustic transducer is a piezoelectric electro-acoustic transducer air transducer collector, characterized in that.