JP2004056202

Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2004056202
The present invention provides an acoustic device that can function as a speaker and can be
made thinner. A core (5) on which permanent magnets (4) and drive coils (6) are wound is
opposed in parallel in a direction along a surface of a diaphragm (10) on bases (3, 3) provided on
both sides of a frame (2). Is provided. The vibrating plate 10 is provided with magnetic bodies 11
a and 11 b, and the magnetic bodies 11 a and 11 b are located between the permanent magnet 4
and the core 5. The magnetic bodies 11a and 11b are attracted by the permanent magnet 4, and
by energizing the drive coil 6, the magnetic bodies 11a and 11b can be moved to the core 5 side.
By vibrating the magnetic members 11a and 11b in the X direction in this manner, it is possible
to vibrate the diaphragm 10 in the Z direction to generate sound. [Selected figure] Figure 2
Sound equipment
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
thin acoustic device that can be used, for example, as a speaker. 2. Description of the Related Art
FIG. 5 is a cross-sectional view showing the structure of a conventional speaker used as an
acoustic device. In an acoustic device 50 shown in FIG. 5, a concave lower yoke 52 made of a
magnetic material is provided at the center of a frame 51, and a permanent magnet 53 is fixed at
the center. For example, the permanent magnet 53 is magnetized such that the Z1 side is the N
pole and the Z2 side is the S pole. An upper yoke 54 made of a magnetic material is fixed to an
end surface of the permanent magnet 53 on the Z1 side, and an end surface 54a in the outer
circumferential direction is opposed to the inner wall 52a of the lower yoke 52 with a
predetermined gap G therebetween. A stepped portion 50 a is provided on the outer peripheral
portion of the frame 51, and an edge portion on the outer peripheral side of the diaphragm 56 is
circumferentially fixed to the stepped portion 50 a. A bobbin 59 formed of paper or the like is
fixed to the lower portion of the diaphragm 56, and a voice coil 60 is wound around the outer
03-05-2019
1
peripheral surface thereof. The bobbin 59 having the voice coil 60 is disposed in the gap G. In
the acoustic device 50 thus formed, a magnetic drive means is formed by the lower yoke 52, the
permanent magnet 53, the upper yoke 54, the gap G and the voice coil 60, and the N pole of the
permanent magnet 53, the upper portion A magnetic circuit (magnetic path) is formed, which is a
path that sequentially passes through the outer edge of the yoke 54, the gap G, the voice coil 60,
the inner wall 52a of the lower yoke 52, and the S pole of the permanent magnet 53 in order.
When sound information is output from the disk player connected to the sound device 50, a
current based on the sound information flows to the voice coil 60, whereby the bobbin 59 moves
in the Z direction. By this operation, the diaphragm 56 vibrates in the Z direction to generate a
sound. However, in the conventional acoustic device of this type, the lower yoke 52, the
permanent magnet 53, and the upper yoke 54 for forming the magnetic circuit are opposed to
the surface of the diaphragm 56. Since the structure is vertically stacked in the Z direction, the
thickness dimension becomes thick, and it has been difficult to reduce the thickness of the
device. The present invention is to solve the above-mentioned conventional problems, and it is an
object of the present invention to provide an acoustic device which can exhibit a function as a
speaker or the like and which can be thinned.
The present invention comprises a magnetic body provided on a diaphragm and magnetic drive
means for applying a moving force to the magnetic body, and the moving force from the
magnetic drive means is provided. By reciprocating the magnetic body in a direction along the
surface of the diaphragm, the diaphragm is vibrated in a direction intersecting with the surface.
For example, the magnetic drive means is configured as a set of a magnet and a core on which a
drive coil is wound, and the magnet and the core are provided opposite to each other across the
magnetic body. There is. In this case, the magnetic material is magnetized by the magnet and
biased in a predetermined direction, and the switching operation of the current supply to the
drive coil causes the magnetic material to approach the core, and It can be configured to be
vibrated in a direction away from the core. In the present invention, a magnetic circuit composed
of the magnet and the core provided with the drive coil can be provided along the diaphragm,
respectively, and there is no need to overlap in the thickness direction. Can be Preferably, the
vibrating plate is provided with a bending portion. The bending portion can be formed, for
example, by integrating the diaphragm in a U-shape. Preferably, the magnetic substance is a thin
film of magnetic material. By forming the magnetic body thin as described above, the operation
of the diaphragm is not impeded, and the diaphragm can be operated smoothly. A space may be
provided on the back side of the diaphragm where the magnetic body and the magnetic drive
means are not provided. If this space is formed, a circuit member or the like can be positioned in
this space, so that further downsizing and thinning can be achieved. FIG. 1 is a plan view showing
an example of a speaker as an acoustic device according to the present invention, FIG. 2 is a
sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a partially enlarged view of FIG. FIG.
The acoustic device 1 shown in FIG. 1 has a frame 2. The frame 2 is formed by injection molding
using a synthetic resin material, die-cast molding using an aluminum alloy, a zinc alloy, or the
03-05-2019
2
like. The frame 2 is formed in the shape of a square plate and has a small thickness, and a central
portion in the X direction of the bottom surface thereof is extruded on the Z1 side. Thereby, as
shown in FIG. 2, the recessed part 2b, 2c is formed in the both sides of a X direction.
Further, as shown in FIG. 2, on the back surface side of the frame 2, a concave space 2a facing
the Z2 side is formed by the concave portions 2b and 2c. As shown in FIG. 2, resin molded bases
3 and 3 are fixed to the concave portions 2 b and 2 c of the frame 2, respectively. Mounting walls
3a and 3b vertically formed in the Z1 direction are integrally formed at the ends of the bases 3
and 3 in the X direction. Permanent magnets 4 and a core 5 are fixed to the upper surfaces of the
bases 3 and 3, respectively, and a drive coil 6 is wound around the core 5. As shown in FIG. 1, the
permanent magnet 4, the core 5 and the drive coil 6 are each formed to be elongated in the Y
direction, and the permanent magnet 4 and the core 5 are opposed to each other at a
predetermined interval. The core 5 is formed in a plate shape of a magnetic material such as iron
or ferrite, and is bent so that the tip facing the permanent magnet 4 is inclined to the Z1 side. In
the present embodiment, a magnetic drive means is constituted by the core 5 provided with the
permanent magnet 4 and the drive coil 6. In the acoustic device 1, a diaphragm 10 covering the
entire front surface of the frame 2 is provided along an X-Y plane. The diaphragm 10 is formed
in a square shape of a paper material, a laminate of a paper material and a resin film, a paper
material impregnated with a resin, or the like, and both edges of the diaphragm 10 on the X side
are the above. An adhesive or the like is fixed to the upper surfaces of the mounting walls 3a and
3b integrally formed with the bases 3 and 3, respectively. As shown in FIG. 2, the height
dimension to the upper surface of the mounting walls 3a, 3b is set higher than the height
dimension of the upper surface 4a of the permanent magnet 4, and the diaphragm 10 is a
mounting wall When supported by 3a and 3b, a gap is formed between the permanent magnet 4
and the top surface 4a. Further, the tip of the core 5 bent toward the Z1 side is also set at a
height not to contact the diaphragm 10. As shown in FIG. 1, on the back surface of the
diaphragm 10, that is, on the surface facing the magnetic driving means, magnetic bodies 11a
and 11b formed in a thin foil shape in the Y direction are provided. The magnetic bodies 11a and
11b are formed of a magnetic material such as iron or ferrite, and are fixed to the diaphragm 10
with an adhesive or the like. The magnetic members 11a and 11b are located between the
permanent magnet 4 and the core 5 provided with the drive coil 6, respectively. The vibrating
plate 10 is provided with a pair of bending portions 12 a and 12 b extending in the Y direction
inside the core 5.
The flexures 12a and 12b are formed by bending the diaphragm 10 in a U-shape. Next, the
operation of the audio device 1 of the present embodiment will be described. As shown in FIG. 3,
for example, the permanent magnet 4 is magnetized such that the inner side in the X direction is
an N pole and the outer side is an S pole. The magnetic body 11 a is always biased in the
direction of moving to the permanent magnet 4 side under the influence of the magnetic lines of
03-05-2019
3
force from the N pole to the S pole of the permanent magnet 4. That is, in a state where the drive
coil 6 is not energized, a suction force is applied to the permanent magnet 4 positioned on the
X2 side with respect to the magnetic body 11a. The other magnetic body 11b located on the side
of the recess 2c is biased in the X1 direction opposite to the above. Therefore, in a state in which
no current flows in the drive coil 6, the diaphragm 10 is pulled from both sides and set in a state
without bending. Then, when a current flows through the drive coil 6, the core 5 is magnetized so
as to generate a force for attracting the magnetic body 11 a, and the attraction generated
between the magnetic body 11 a and the permanent magnet 4. The magnetic body 11a moves in
the X1 direction because the force is excessive. The magnetic body 11b is also moved in the X2
direction in the same manner. As described above, when the magnetic body 11a is moved in the
X1 direction and the magnetic body 11b is moved in the X2 direction, the diaphragm 10 is bent
and deformed in the Z1 direction or the Z2 direction by the bending portions 12a and 12b. When
the current flow is stopped by cutting the energization of the drive coil 6, the attractive force
between the magnetic members 11a and 11b and the cores 5 and 5 disappears, and the magnetic
members 11a and 11b and the permanent magnet 4 By the magnetic attraction force between 4
and 4, the magnetic bodies 11a and 11b are respectively moved in the X2 direction and the X1
direction, and the diaphragm 10 is returned to the initial state in which it is pulled to both sides.
As described above, the magnetic bodies 11 a and 11 b are vibrated in the X direction along the
surface of the diaphragm 10 by repeating the operation of switching the power supply off and on
to the drive coil 6. The vibration operation of the magnetic bodies 11a and 11b is converted into
the vibration operation in the Z direction of the diaphragm 10 between the flexures 12a and 12b,
and a sound based on the vibration is generated from the diaphragm 10. In this embodiment,
since the permanent magnet 4 and the core 5 provided with the drive coil 6 can be arranged in
the direction along the diaphragm 10, it is possible to arrange the magnet and the core in the
thickness direction. The thickness of the device can be reduced.
Further, in this embodiment, since the magnetic body and the magnetic drive means can be
provided on both ends in the X direction, it is not necessary to provide the magnetic drive means
on the back side of the diaphragm 10. A space 2a can be provided. Therefore, it is also possible
to construct a thin and compact device by housing a circuit member such as a substrate in the
space 2a. Although the device having the function of a speaker for generating sound has been
described in the present embodiment, the present invention is also applicable to a device having
a function of a microphone. The function as a microphone is made possible by detecting the
amount of current flowing in the coil wound around the core and the direction thereof. In the
detection operation, when a sound is given to the diaphragm 10, the diaphragm 10 is vibrated in
the Z direction by the sound pressure of the sound. By the vibration operation of the diaphragm
10, the magnetic bodies 11a and 11b are moved in the X direction, and a current based on the
operation of the magnetic bodies 11a and 11b is induced in the drive coil 6. By detecting the
amount of current induced and the direction thereof, a signal based on the sound is generated.
Further, in the present embodiment, the magnetic drive means is constituted by the permanent
03-05-2019
4
magnet 4 and the core 5 around which the drive coil 6 is wound, but when the magnetic body 11
is a permanent magnet, the permanent magnet 4 is eliminated. The configuration is also possible
and further miniaturization can be achieved. Moreover, although the magnetic drive means was
provided in the both sides of the diaphragm, respectively, the structure provided only in one side
may be sufficient. FIG. 4 is a cross-sectional view showing a modification of the acoustic device of
the present invention. The acoustic device 30 shown in FIG. 4 has a frame 31 which is formed
into a portal shape by bending the both sides of the frame 2 at right angles. The same magnetic
drive means as the acoustic device 1 is provided in the concave portions on both sides of the
bent frame 31. Further, the diaphragm 32 is supported on the frame 31 along the shape thereof,
and the magnetic members 11 a and 11 b are fixed to the back surface of the diaphragm 32. In
addition, the other structure attaches ¦ subjects the same code ¦ symbol and abbreviate ¦ omits
the description. In the embodiment shown in FIG. 4, by vibrating the magnetic members 11 a and
11 b simultaneously in the Z1-Z2 direction, the diaphragm 10 set horizontally to the X axis can
be vibrated in the Z direction. , Can function as a speaker. Also in this case, as described above, it
can also function as a microphone.
In this embodiment, thinning of the device can be partially achieved, and for example, other
circuit members can be accommodated in the inner space surrounded by the frame 2. Further, in
the acoustic device of the present invention, in the shape shown in FIG. 1, the dimension in the Y
direction can be formed short, and a speaker or a microphone elongated in the X direction can
also be configured. Further, in the acoustic device 1, the frame 2 R in the region of the space 2 a
formed in a concave shape and the diaphragm 10 facing the frame 2 R are respectively formed of
transparent members, and A sound may be generated from the front of the display screen of the
display device or the operation surface of the input device by installing a display device formed
of a display panel, an input device provided with an operation surface, or the like. Similarly, in
the acoustic device 30, the frame 31R of a part of the frame 31 and the diaphragm 32 facing the
frame 31R may be respectively formed transparent to allow installation of the display member
and the input member. According to the present invention described above, a magnetic body is
provided on the diaphragm and this magnetic body is driven in the direction along the surface of
the diaphragm, and a magnetic circuit constituting the magnetic drive means Since the parts can
be installed in parallel to the diaphragm, thinning of the device can be achieved. BRIEF
DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an acoustic device according to
the present invention, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, FIG. 3 is a partially
enlarged sectional view of FIG. Fig. 4 is a side view showing a modification of the acoustic device
according to the present invention, and Fig. 5 is a sectional view showing a conventional acoustic
device. Description of symbols 2 frame 2a space 2b, 2c recess 3 base 3a, 3b mounting wall 4
Permanent magnet 5 Core 6 Drive coil 10 Diaphragm 11a, 11b Magnetic body 12a, 12b Flexure
part
03-05-2019
5