DESCRIPTION JP2004343602

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DESCRIPTION JP2004343602
The present invention relates to a speaker used for various audio devices and information
communication devices, and the reduction of leakage magnetic flux has been a problem. A
speaker according to the present invention is formed by extending an outer peripheral portion of
an upper plate 22 of an external magnet type magnetic circuit 24 to cover the magnetic circuit
24 so that the leakage flux from the magnet 21 can be It is configured to be shielded by the
extended outer peripheral portion 22a to reduce the leakage flux to the outside, and the size of
the magnet is limited by the size of the voice coil by adopting the external magnetic type
magnetic circuit configuration. It is possible to use a large magnet without having to make it
possible to achieve high sound pressure. Furthermore, for the above reason, the volume of the
magnetic circuit can be increased, and the heat capacity of the magnetic circuit can be expanded,
so that high input resistance can be achieved. [Selected figure] Figure 1
Speaker, module using the same, and electronic device using the speaker
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker, a module using the same, and an electronic device using the speaker. [0002] A
conventional speaker is a speaker that is often used for information communication devices such
as mobile phones, but usually, to reduce the leakage flux of the magnet, these magnetic circuits
are of the internal magnet type. It is a general configuration method that uses a structure.
However, recently, the market demand for high sound pressure and high input resistance is
severe, and it is becoming difficult to realize the internal magnetic structure. [0004] The reason
for this is that since the magnet is disposed inside the voice coil in the internal magnet type
structure, the size of the magnet is limited by the size of the voice coil, and a large magnet can
not be used. It will not be possible to pressurize. Further, for the above reason, the volume of the
magnetic circuit can not be increased, so the heat capacity of the magnetic circuit can not be
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expanded, and the input resistance can not be increased. From the above background, the use of
external magnet speakers is being reviewed. Further, as another requirement, the market demand
for the miniaturization of mobile phones is severe, and in the past, a round speaker has been
mainstream, but a slim type such as a square or a track type has recently been attracting
attention. For this reason, there are many cases where the magnetic circuit, which was once
formed in a round shape, is recently formed in a square shape to improve the space factor for the
magnetic circuit. Based on the above background, a conventional external magnet type speaker
will be described. FIG. 9 shows a cross-sectional view of a conventional external magnet type
speaker. As shown in FIG. 9, the magnet 1 is sandwiched between the upper plate 2 and the
lower plate 3 to form a magnetic circuit 4. The frame 6 is coupled to the magnetic circuit 4, and
the diaphragm 7 is coupled to the outer peripheral portion of the frame 6. The voice coil 8 is
coupled to the diaphragm 7, and a part of the voice coil 8 is disposed in the magnetic gap 5 of
the magnetic circuit 4. Then, a protector 9 is coupled to the outer peripheral portion of the frame
6 so as to cover the diaphragm 7. Here, the speaker can use a large magnet by the external
magnetic type magnetic circuit configuration, and can achieve high sound pressure. Furthermore,
high input resistance can be achieved by the improvement of the heat capacity of the magnetic
circuit and the improvement of the heat dissipation of the voice coil.
For example, Patent Document 1 is known as prior art document information related to the
invention of this application. [Patent Document 1] Japanese Patent Application Laid-Open No. 63146691 [0012] The above-mentioned speaker is an external magnet type magnetic circuit so
that the size of the magnet can be freely set. It is a structure. Therefore, since the magnet is
configured to be exposed to the outside, the leakage flux from the magnet is large, and this
leakage flux has a problem that there is a possibility of adversely affecting the outside. The
present invention is to solve the above-mentioned problems, and to provide an excellent speaker
capable of realizing a reduction in the leakage flux while maintaining the magnetic circuit
configuration of the external magnet type. In order to solve the above problems, the present
invention has the following configuration. In the invention according to claim 1 of the present
invention, a frame is connected to an external magnet type magnetic circuit in which a magnet is
held between an upper plate and a lower plate, and a vibration is connected to the outer
peripheral portion of the frame. A speaker comprising: a plate; and a voice coil coupled to the
diaphragm and a part of the plate being disposed in a magnetic gap of the magnetic circuit,
wherein the upper plate extends the outer periphery thereof to form the magnetic A speaker is
formed by covering the circuit. With this configuration, the leakage flux from the magnet is
shielded by the extended outer peripheral portion of the top plate, and the leakage flux to the
outside can be reduced. According to a second aspect of the present invention, the outer shape of
the magnetic circuit is configured in a square shape. With this configuration, the space factor of
the magnetic circuit can be improved. According to a third aspect of the present invention, the
shape of the magnetic gap is constituted by two linear shapes. This configuration can improve
the material utilization rate of the magnetic circuit and the productivity. According to a fourth
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aspect of the present invention, the magnetic gap is formed in a track shape. This configuration
can improve the productivity of the voice coil. The invention according to claim 5 of the present
invention is configured by dividing the magnet into at least two or more. With this configuration,
the magnetic circuit can be further slimmed down. According to a sixth aspect of the present
invention, the top plate is divided into two parts to constitute a magnetic circuit.
This configuration can improve the material utilization rate of the magnetic circuit and the
productivity. According to the seventh aspect of the present invention, a gap is provided between
the magnet and the extension of the upper plate formed to cover the magnetic circuit. With this
configuration, since the magnetic pole of the magnet is not magnetically shorted due to the gap
between the extension of the upper plate and the magnet, the magnetic gap can maintain a high
magnetic flux density and maintain high sound pressure of the speaker. can do. In the invention
according to claim 8 of the present invention, the material thickness of the extension portion of
the upper plate is thinner than the material thickness of the upper plate to constitute a magnetic
circuit. With this configuration, the material utilization rate of the magnetic circuit can be
improved and further slimmed down. According to a ninth aspect of the present invention, the
extension of the upper plate formed to cover the magnetic circuit is further extended to cover the
entire magnetic circuit, and is further extended. It is. This configuration can further reduce the
leakage flux. According to a tenth aspect of the present invention, a magnetic circuit is
configured by bending and molding an upper plate at least a sheet-like metal body. This
configuration can improve the material utilization rate of the magnetic circuit and the
productivity. According to an eleventh aspect of the present invention, a part of the upper plate is
inserted and co-molded with a frame by resin so as to be bonded. With this configuration, the
productivity of the speaker can be improved. According to a twelfth aspect of the present
invention, a module is configured by combining any one of the loudspeakers according to the
first to eleventh aspects and an electronic circuit. With this configuration, it is possible to
inexpensively provide a module in which a speaker and an electronic circuit are combined.
According to a thirteenth aspect of the present invention, there is provided an electronic
apparatus comprising the speaker according to any one of the first to eleventh aspects. This
configuration can provide an electronic device with low leakage flux. BEST MODE FOR
CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be
described with reference to the drawings. In addition, about the description of each embodiment,
the thing similar to Embodiment 1 is demonstrated, abbreviate | omitting the description. First
Embodiment The invention according to the first, the seventh, and the eighth aspects of the
present invention will be described below using the first embodiment.
FIG. 1 shows a cross-sectional view of a speaker according to an embodiment of the present
invention. As shown in FIG. 1, the magnet 21 is sandwiched between an upper plate 22 and a
lower plate 23 to form a magnetic circuit 24. Here, the upper plate 22 is formed by extending the
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outer peripheral portion thereof to provide an upper plate extension 22 a and bending so as to
cover the magnet 21. In the bent portion of the upper plate extension 22a, a gap is provided
between the upper plate extension 22a and the magnet 21 so that the magnetic pole of the
magnet 21 is not magnetically shorted under the influence of the upper plate extension 22a. By
configuring in, the magnetic flux density of the magnetic gap is maintained. Furthermore, the
material thickness of the upper plate extension portion 22a is formed thinner than the material
thickness of the upper plate 22, thereby improving the material utilization rate and further
slimming. A frame 26 is coupled to the magnetic circuit 24, and a diaphragm 27 is coupled to an
outer peripheral portion of the frame 26. Then, the voice coil 28 is coupled to the diaphragm 27
and a part of the voice coil 28 is disposed in the magnetic gap 25 of the magnetic circuit 24.
Then, a protector 29 is coupled to the outer peripheral portion of the frame 26 so as to cover the
diaphragm 27. According to this configuration, the leakage flux from the magnet 21 can be
shielded by the upper plate extension 22a, and the leakage flux to the outside can be reduced. As
described above, by using the external magnetic type magnetic circuit configuration, the size of
the voice coil 28 can be used without the size of the magnet 21 being limited, so that the high
sound pressure can be achieved. Can be Furthermore, for the above reason, the volume of the
magnetic circuit 24 can be increased, and the heat capacity of the magnetic circuit 24 can be
expanded, so that high input resistance can be achieved. Therefore, in the present embodiment, it
is possible to realize an excellent speaker capable of realizing the reduction of the leakage flux
without increasing the number of component parts of the speaker while having the magnetic
circuit configuration of the external magnet type. Further, in the present embodiment, the
material thickness of the upper plate extension portion 22a is formed thinner than the material
thickness of the upper plate 22, thereby improving the material utilization rate and further
slimming. The upper plate 22 is a part of components constituting the magnetic circuit 24.
Therefore, if the thickness of the material is too thin, the magnetic saturation of the magnetic
circuit 24 is caused, the magnetic flux density of the magnetic gap 25 decreases, and as a result,
the sound pressure level of the speaker decreases. Become.
However, since the upper plate extension 22a is not a part of the component constituting the
magnetic circuit, there is no concern about the occurrence of magnetic saturation as described
above, and the material thickness can be set extremely thin. It is. That is, if the minimum material
thickness sufficient to shield the leakage flux of the magnet 21 is secured, the purpose is
achieved. Second Embodiment The invention according to the second aspect of the present
invention will be described below with reference to a second embodiment. FIG. 2 is an external
perspective view of component parts of the speaker according to the embodiment of the present
invention. Only differences from the first embodiment will be described. As shown in FIG. 2, the
outer shape of the magnetic circuit 24 is configured in a square shape. Then, the shape of the
speaker is also formed in a square shape like the magnetic circuit 24. That is, the voice coil 28,
the diaphragm 27, and the frame 26 are all formed in a square shape. According to this
configuration, the space factor of the magnetic circuit 24 can be improved. Therefore,
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miniaturization of the set or module when using the speaker can be realized. The first
embodiment is a cross-sectional view of the speaker, and is mainly described on the assumption
of a round magnetic circuit, but the present invention is not limited to this and can be applied to
a square. In the second embodiment, the outer shape of the magnetic circuit is limited to the
square shape. Furthermore, it is possible to freely set a combination of the outer shape of the
magnetic circuit in a square shape and the shape of the voice coil, the diaphragm, and the frame
in a round shape. The detailed description is the same as that of the first embodiment and thus
will be omitted. Third Preferred Embodiment The third preferred embodiment of the present
invention will be described below with reference to the third preferred embodiment, the fifth
preferred embodiment, the sixth preferred embodiment, and the tenth preferred embodiment of
the present invention. FIG. 3 is an external perspective view of a magnetic circuit according to an
embodiment of the present invention. The differences from the first embodiment and the second
embodiment will be described. As shown in FIG. 3, the magnetic circuit 24A is formed by
sandwiching the two rod-shaped magnets 21A with the two upper plates 22A and the lower plate
23. Are configured. Here, the upper plate 22A is formed by bending a sheet-like metal body. With
this configuration, the shape of the magnetic gap can be configured from two linear shapes.
According to this configuration, it is possible to improve the material utilization factor and the
productivity of the magnetic circuit 24A.
Furthermore, the magnetic circuit can be further slimmed down. Further, in this configuration,
although both the magnet 21 A and the upper plate 22 A are configured to be divided into two,
as shown in the second embodiment, it is configured without dividing one of them. There is also
a way to do it. Also in the present embodiment, the upper plate extension 22Aa is formed only in
the major axis direction of the square magnetic circuit having a large effect in the present
embodiment, and the countermeasure against the leakage flux is implemented. You may. As
described above, it is important to form the top plate extension at a position where a measure
against the leakage flux of the speaker is required. The detailed description is omitted because it
is the same as that of the first embodiment. Fourth Embodiment The fourth embodiment of the
present invention will be described below with reference to the fourth aspect of the present
invention. FIG. 4 is an external perspective view of a magnetic circuit according to an
embodiment of the present invention. Only the points different from the above will be described.
As shown in FIG. 4, the magnetic gap shape is formed from a track shape. That is, the inner
diameter of the upper plate 22 B is formed in a track shape, and the center pole of the lower
plate 23 B is also formed in a track shape, whereby the magnetic gap is formed in a track shape.
According to this configuration, it is possible to use a track type voice coil having higher
production efficiency than a square type voice coil, and further to form a magnetic gap in the
short diameter direction of the voice coil. Can also be maintained. Therefore, the productivity of
the speaker can be improved. In the present embodiment, the upper plate extension 22Ba is
formed in both the major axis direction and the minor axis direction of the magnetic circuit 24B,
and hence the major axis direction and the minor axis. Countermeasures against leakage flux are
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implemented in both directions. The position at which the upper plate extension 22Ba is formed
can be set to only one of the major axis direction and the minor axis direction as described above.
Also, it can be freely set only at necessary positions, such as one side in the major axis direction
and one side in the minor axis direction. Fifth Embodiment The fifth embodiment of the present
invention will be described below with reference to FIG. FIG. 5 shows a cross-sectional view of a
loudspeaker according to an embodiment of the present invention.
Only the differences will be described. As shown in FIG. 5, the extension 22Ca of the top plate
22C formed to cover the magnetic circuit 24C is further extended to cover the entire magnetic
circuit 24C and further extended more. Formed. With this configuration, the leakage flux can be
further reduced by further extending the extension 22Ca of the upper plate 22C. Sixth
Embodiment The invention according to the eleventh aspect of the present invention will be
described below with reference to the sixth embodiment. FIG. 6 is a cross-sectional view of a
loudspeaker according to an embodiment of the present invention. Only the points different from
the above will be described. As shown in FIG. 6, a part of the upper plate 22D is inserted, and it is
formed by resin simultaneously with the frame 26 and coupled. With this configuration, the
frame 26 and the upper plate 22D can be coupled by insert molding simultaneously with the
molding of the frame 26, so that the productivity of the speaker can be improved. Seventh
Embodiment The invention according to the twelfth aspect of the present invention will be
described below with reference to a seventh embodiment. FIG. 7 shows a cross-sectional view of
a module according to an embodiment of the present invention. As shown in FIG. 7, a module 50
is configured by integrating any one of the speakers 30 according to claims 1 to 11 and the
electronic circuit 40. Here, as a configuration of the module 50, the electronic component 42 is
fixed to the circuit board 41 and wired to configure the electronic circuit 40. Then, the electronic
circuit 40 and any one of the speakers 30 according to the above-mentioned claims 1 to 11 are
integrally coupled to constitute a module 50. FIG. 7 shows an example in which the loudspeaker
described in Embodiment 6 is integrally coupled. The electronic circuit 40 includes at least an
amplifier circuit of an audio signal supplied to the speaker. That is, since the circuit for
amplifying the signal-processed audio signal to a level necessary for outputting from the speaker
is already integrated with the speaker and the internal wiring is also provided, it is only
necessary to combine this module Audio output easily. Furthermore, in the electronic circuit 40,
in addition to the above-mentioned amplification circuit, if it is a communication device such as a
mobile phone, a circuit necessary for communication such as a detection circuit, modulation
circuit, demodulation circuit, etc. A drive circuit for the means, and various circuits such as a
power supply circuit and a charging circuit can also be included.
With this configuration, the speaker and the electronic circuit, which are conventionally
manufactured separately, are supplied to the production base of the electronic device such as a
mobile phone through each inspection process and distribution process, are integrated and
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modularized. As a result, the production process, the inspection process, and the distribution
process can be integrated, and significant cost reduction can be implemented. Thus, the module
50 in which the speaker 30 and the electronic circuit 40 are combined can be provided at low
cost. Eighth Embodiment The invention according to the thirteenth aspect of the present
invention will be described below with reference to the eighth embodiment. FIG. 8 is a crosssectional view of an essential part of an electronic device according to an embodiment of the
present invention. As shown in FIG. 8, an electronic device 80 is configured by mounting any one
of the speakers 30 according to any one of claims 1 to 11. FIG. 8 shows an example in which the
speaker described in Embodiment 6 is mounted. Here, as a configuration of the electronic device
80, the speaker 30, the electronic circuit 40, the components such as the display module 60 such
as liquid crystal, and the module are mounted inside the exterior case 70 to configure a mobile
phone. With this configuration, an electronic device with low leakage flux can be provided. As
described above, according to the present invention, the outer peripheral portion of the upper
plate is extended to form a speaker by covering the magnetic circuit. With this configuration, the
leakage flux from the magnet is shielded by the extended outer peripheral portion of the top
plate, and the leakage flux to the outside can be reduced. As described above, by using the
external magnetic type magnetic circuit configuration, a large magnet can be used without the
size of the magnet being limited by the size of the voice coil, and high sound pressure can be
achieved. Can. Furthermore, for the above reason, the volume of the magnetic circuit can be
increased, and the heat capacity of the magnetic circuit can be expanded, so that high input
resistance can be achieved. Therefore, the present invention can provide an excellent speaker
which can realize the reduction of the leakage flux without increasing the number of component
parts of the speaker while having the magnetic circuit configuration of the external magnet type,
which is industrially The value is huge. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a crosssectional view of a loudspeaker according to an embodiment of the present invention. FIG. 2 is an
external perspective view showing component parts of the loudspeaker according to an
embodiment of the present invention. FIG. 4 is an external perspective view of a magnetic circuit
according to an embodiment of the present invention. FIG. 4 is an external perspective view of a
magnetic circuit according to an embodiment of the present invention. FIG. 5 is a sectional view
of a speaker according to an embodiment of the present invention. FIG. 7 is a cross-sectional view
of a module according to an embodiment of the present invention. FIG. 8 is a cross-sectional view
of an electronic device according to an embodiment of the present invention. Speaker crosssectional view of [speaker] 21 magnet 21A magnet 22 top plate 22a top plate extension 22A top
plate 22Aa top plate extension 22B top plate 22Ba top plate 22 C upper plate 22 Ca upper plate
extension 22 D upper plate 22 Da upper plate extension 23 lower plate 23 B lower plate 24
magnetic circuit 24 A magnetic circuit 24 B magnetic circuit 24 C magnetic circuit 24 D
magnetic circuit 25 magnetic gap 26 frame 27 diaphragm 28 Voice coil 29 Protector 30 Speaker
40 Electronic circuit 41 Circuit board 42 Electronic component 50 Module 60 Display module 70
Exterior case 80 Electronic equipment
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