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DESCRIPTION JPH07298389

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DESCRIPTION JPH07298389
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
loudspeaker having an elongated structure and excellent sound quality.
[0002]
2. Description of the Related Art In recent years, with the spread of so-called high vision and wide
vision televisions, etc., the screen of a television is becoming generally wide. On the other hand,
however, narrow and thin television sets as a whole are desired from the housing situation in
Japan.
[0003]
Since a speaker unit for television (hereinafter referred to as a speaker) is usually attached to
both sides of a cathode ray tube, it contributes to increasing the width of the television set.
Therefore, a speaker having a slender structure such as a square shape or an oval shape has
conventionally been used for television. Further, as the width of the cathode ray tube is
increased, it is required to further narrow the width of the speaker, and at the same time, it is
also required to improve the sound quality of the audio corresponding to the high image quality
of the screen.
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[0004]
Here, a conventional elongated speaker will be described with reference to FIGS. 16 to 18. FIG.
16 is a block diagram of a conventional elongated speaker, (a) is a plan view, (b) is a crosssectional view in the major axis direction, and (c) is a cross-sectional view in the minor axis
direction. In the figure, the diaphragm 1e is an elongated diaphragm which generates air
vibration, and has dimensions as shown in FIG. 18, for example. An edge 3e is bonded to the
outer peripheral portion of the diaphragm 1e and is held by the frame 11e.
[0005]
A voice coil bobbin 6e is fixed to the central portion of the diaphragm 1e, and is held by the
frame 11e so as to be able to vibrate via the damper 4e. On the other hand, a magnetic circuit 26
comprising a yoke 8e, a magnet 9e and a plate 10e is provided in the central recess of the frame
11e. Then, the voice coil wound around the voice coil bobbin 6e is held in the air gap of the
magnetic circuit 26, and the voice coil bobbin 6e performs a piston motion by the drive current,
and the diaphragm 1e vibrates in that direction. As a result, sound waves are emitted from the
diaphragm 1e.
[0006]
FIG. 17 shows the frequency characteristic of the reproduction sound pressure level of this
speaker, and the vertical axis shows the reproduction sound pressure level at a point of 1 m on
the front axis when 1 W is inputted to this speaker, and the horizontal axis shows a drive
Indicates the frequency.
[0007]
However, the above-mentioned conventional loudspeakers have the following problems.
That is, in the loudspeaker shown in FIG. 16, since the driving method is adopted in which the
central portion of the elongated diaphragm 1e is point driven, split resonance in the long axis
direction is likely to occur. As a result, in the middle and high frequencies, peak-dips occur on the
frequency characteristics of the reproduced sound pressure, resulting in deterioration of the
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sound quality. For example, on the characteristics shown in FIG. 17, noticeable dips are seen at 2
kHz, 3 kHz and 5 kHz.
[0008]
Further, the width of the drive system including the magnetic circuit 26 and the voice coil bobbin
6e needs to be smaller than the length of the short diameter of the speaker. Therefore, in the
speaker having such a structure, it is physically impossible to increase the diameter of the voice
coil bobbin 6e, and therefore, the wire length L of the voice coil can not be increased. Further,
since the volume of the magnet 9e is also limited to a small size, the magnetic flux density B of
the air gap can not be sufficiently secured. As a result, the force coefficient (B × L) of the drive
system becomes small, making it difficult to increase the conversion efficiency. Furthermore, it is
necessary to reduce the radius of curvature and the width of the damper 4e so as to be
accommodated inside the frame 11e. As a result, the stiffness of the vibration system is
increased, and the lowest resonance frequency f0 is increased, which makes it difficult to
reproduce the bass range.
[0009]
The present invention has been made in view of such conventional problems, and it is difficult to
cause split resonance and obtain flat frequency characteristics while having a narrow width (long
and narrow structure), and the conversion efficiency is enhanced. An object of the present
invention is to obtain a speaker with excellent sound quality, which is capable of reproducing the
bass band by suppressing the frequency f0 to a low level.
[0010]
The invention according to claim 1 of the present application is a non-axisymmetric shape having
a major axis and a minor axis when viewed in the direction of vibration, and is convex in the
direction of sound emission. A curved diaphragm, a voice coil bobbin formed in a strip parallel to
the vibration direction along the outer peripheral portion of the diaphragm, and a band-like
upper end bonded to the outer peripheral portion of the diaphragm, and an outer peripheral
surface of the voice coil bobbin It is characterized by comprising a wound voice coil and a
magnetic circuit for giving a magnetic flux for vibration to the voice coil.
[0011]
The invention according to claim 2 of the present application is a non-axisymmetric diaphragm
having a major axis and a minor axis as viewed in the vibration direction, and a non-axial plane
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having the major axis and the minor axis as viewed from the vibration direction. A voice coil
bobbin which is symmetrical, and at least a part of which is a straight part parallel to each other
in the direction of the major axis and whose upper end is adhered to a diaphragm, and a voice
coil wound around the outer peripheral surface of the voice coil bobbin And a magnetic circuit
for applying a vibrating magnetic flux to the voice coil, wherein the magnetic circuit drives a
linear portion of the voice coil bobbin.
[0012]
In the invention of claim 3 of the present application, the magnetic circuit is fixed to the yoke
having a concave cross section, a magnet fixed to the bottom of the yoke, and a magnet fixed to
the top of the magnet, and opposed to the inner side surface of the yoke via a gap. And the
magnet is magnetized in the vibration direction of the diaphragm.
[0013]
In the invention of claim 4 of the present application, the magnetic circuit is fixed to the yoke
having a concave cross section and one of the inner side surfaces of the yoke, and is opposed to
the other inner side surface of the yoke via an air gap. A magnet is provided which is magnetized
in the direction perpendicular to the vibration direction, and two sets of magnetic circuits are
provided with the central axis of the major axis of the diaphragm as a symmetry axis.
[0014]
In the invention of claim 5 of the present application, the non-axisymmetric diaphragm having a
major axis and a minor axis in a plan view seen from the vibration direction, a voice coil bobbin
bonded to the diaphragm, and an outer peripheral surface of the voice coil bobbin. The voice coil
bobbin includes a voice coil wound and a magnetic circuit for applying a magnetic flux for
vibration to the voice coil, and the voice coil bobbin is parallel to the outer peripheral portion of
the diaphragm at an upper end portion formed in a band shape parallel to the vibration direction.
It is characterized in that the linear protrusion has a fold integrally formed.
[0015]
In the invention of claim 6 of the present application, the non-axisymmetric diaphragm having a
major axis and a minor axis in plan view seen from the direction of vibration, a voice coil bobbin
bonded to the diaphragm, and an outer peripheral surface of the voice coil bobbin. The voice coil
bobbin includes a voice coil wound and a magnetic circuit for applying a magnetic flux for
vibration to the voice coil, and the voice coil bobbin is parallel to the outer peripheral portion of
the diaphragm at an upper end portion formed in a band shape parallel to the vibration direction.
It is characterized in that a rib having a linear protrusion is provided.
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[0016]
In the invention according to claim 7 of the present application, the non-axisymmetric diaphragm
having a major axis and a minor axis in plan view seen from the vibration direction, a voice coil
bobbin bonded to the diaphragm, and an outer peripheral surface of the voice coil bobbin. The
voice coil includes a wound voice coil and a magnetic circuit for applying a magnetic flux for
vibration to the voice coil, and the voice coil bobbin is parallel to the vibration direction of the
diaphragm between surfaces facing each other in the minor axis direction of the diaphragm. And
a thin plate-like reinforcing member stretched at a right angle to the opposite surface, and the
magnetic circuit is provided with a plurality of magnetic circuits via a predetermined gap so as to
sandwich the reinforcing member in a vibrating manner. It is
[0017]
In the invention according to claim 8 of the present application, the non-axisymmetric diaphragm
having a major axis and a minor axis in a plan view seen from the vibration direction, a voice coil
bobbin bonded to the diaphragm, and an outer peripheral surface of the voice coil bobbin. An
arc-shaped thin plate reinforcing member comprising: a wound voice coil; and a magnetic circuit
for applying a magnetic flux for vibration to the voice coil, wherein the diaphragm is joined to the
inner surface of the diaphragm in the minor axis direction of the diaphragm. It is characterized
by having.
[0018]
In the invention according to claim 9 of the present application, a non-axisymmetric diaphragm
having a major axis and a minor axis in a planar shape viewed from the vibration direction, a
voice coil bobbin bonded to the diaphragm, and an outer peripheral surface of the voice coil
bobbin The voice coil includes a wound voice coil, and a magnetic circuit for applying a magnetic
flux for vibration to the voice coil, and the diaphragm is a circular rib coupled to the inner
surface of the diaphragm in the minor axis direction of the diaphragm. It is characterized in that
it is integrally formed with the plate.
[0019]
The invention according to claim 10 of the present application is a non-axisymmetric shape
having a major axis and a minor axis in a planar shape viewed from the vibration direction,
wherein the diaphragm is convexly curved in the sound emitting direction, and the diaphragm
The strip is joined in the form of a strip along the outer periphery of the diaphragm, and is
formed in the form of a strip parallel to the direction of vibration along the periphery of the
diaphragm with an elastic edge for holding the diaphragm in a vibrating manner A voice coil
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bobbin bonded to the outer peripheral surface of the plate, a voice coil wound around the outer
periphery of the voice coil bobbin, a magnetic circuit for applying a magnetic flux for vibration to
the voice coil, and a vibration coil provided in the minor axis direction A thin plate-like
connecting member joined to the inner surface of the plate, a lower end of the connecting
member vibratably held, a damper provided with an elastic member parallel to the edge, an outer
peripheral portion of the edge, a magnetic circuit, and a damper And a frame to It is an feature.
[0020]
The invention according to claim 11 of the present application is a diaphragm having a nonaxisymmetric shape having a major axis and a minor axis in a planar shape viewed from the
vibration direction, wherein the diaphragm is convexly curved in a sound emitting direction; The
strip is joined in a strip along the outer peripheral surface of the diaphragm, and is formed in a
strip in parallel with the vibration direction along an outer edge of the diaphragm and an elastic
edge for holding the diaphragm in a vibrating manner. A voice coil bobbin bonded to the outer
peripheral portion of the plate, a voice coil wound around the outer peripheral surface of the
voice coil bobbin, a magnetic circuit for applying a magnetic flux for vibration to the voice coil,
and a vibration coil provided in the minor axis direction A thin plate-like connecting member
joined to the inner surface of the plate, a damper provided with an elastic member parallel to the
short diameter direction of the diaphragm, which holds the lower end side of the connecting
member so as to vibrate freely Circuit, frame for holding the damper, It is characterized in that.
[0021]
The invention according to claim 12 of the present application is a diaphragm having a nonaxisymmetric shape having a major axis and a minor axis in plan view seen from the direction of
vibration, and convexly curved in the direction of emitting sound; The strip is joined in the form
of a strip along the outer periphery of the diaphragm, and is formed in the form of a strip parallel
to the direction of vibration along the periphery of the diaphragm, with an elastic edge for
holding the diaphragm in a vibrating manner. A voice coil bobbin bonded to the outer peripheral
portion of the plate, a voice coil wound around the outer peripheral surface of the voice coil
bobbin, a magnetic circuit for applying a magnetic flux for vibration to the voice coil, and a
vibration coil provided in the minor axis direction A thin plate-like connecting member joined to
the outer surface of the plate, a damper which holds the upper end of the connecting member so
as to vibrate freely, a damper parallel to the edge, an attaching member provided on the outer
periphery of the edge and holding the damper Outer circumference of the magnetic circuit,
mounting member It is characterized in that it comprises a frame for holding the.
[0022]
The invention according to claim 13 of the present application is a diaphragm having a non-
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axisymmetric shape having a major axis and a minor axis in a planar shape viewed from the
vibration direction, wherein the diaphragm is convexly curved in a sound emitting direction; The
strip is joined in the form of a strip along the outer periphery of the diaphragm, and is formed in
the form of a strip parallel to the direction of vibration along the periphery of the diaphragm,
with an elastic edge for holding the diaphragm in a vibrating manner. A voice coil bobbin bonded
to the outer peripheral portion of the plate, a voice coil wound around the outer peripheral
surface of the voice coil bobbin, a magnetic circuit for applying a magnetic flux for vibration to
the voice coil, and a vibration coil provided in the minor axis direction A thin plate-like
connecting member joined to the outer surface of the plate, an upper end portion of the
connecting member is vibratably held, a damper parallel to the minor axis of the diaphragm, and
an outer peripheral portion of the edge straddling the diaphragm Mounting member for holding
the damper, and the edge The outer peripheral portion, and is characterized in that it comprises a
frame for holding the magnetic circuit, the mounting member.
[0023]
The invention according to claim 14 of the present application is a diaphragm having a nonaxisymmetric shape having a major axis and a minor axis in a planar shape viewed from the
vibration direction, wherein the diaphragm is convexly curved in a sound emitting direction; The
strip is joined in the form of a strip along the outer periphery of the diaphragm, and is formed in
the form of a strip parallel to the direction of vibration along the periphery of the diaphragm,
with an elastic edge for holding the diaphragm in a vibrating manner. A voice coil bobbin bonded
to the outer peripheral portion of the plate, a voice coil wound around the outer peripheral
surface of the voice coil bobbin, a magnetic circuit for applying a magnetic flux for vibration to
the voice coil, and a vibration coil provided in the minor axis direction A thin plate-like
connecting member joined to the inner surface of the plate and the inner surface of the voice coil
bobbin, a damper which holds the lower end of the connecting member so as to vibrate freely
and parallel to the major axis of the diaphragm, the outer periphery of the edge, magnetic circuit,
Frame to hold the damper , It is characterized in that it comprises a.
[0024]
The invention according to claim 15 of the present application is that the planar shape viewed
from the vibration direction is joined in a band shape along the non-axisymmetric diaphragm
having a major axis and a minor axis along the outer peripheral portion of the diaphragm to
vibrate the diaphragm. The edge comprises a freely held edge, a voice coil bobbin bonded to a
diaphragm, a voice coil wound around the outer periphery of the voice coil bobbin, and a
magnetic circuit for applying a magnetic flux for vibration to the voice coil. In the portion where
the outer peripheral portion of the diaphragm is arc-shaped, the width of the edge is wider than
the portion where the outer peripheral portion is linear.
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[0025]
According to the invention of claims 1 to 4 of the present application having such a feature, the
entire diaphragm is driven by making the shape of the voice coil bobbin the same nonaxisymmetric shape as the diaphragm.
Therefore, split resonance in the long axis direction is less likely to occur.
Furthermore, the wire length of the voice coil is considerably longer than that of the conventional
one, and the volume of the magnet can be increased, so that the driving force is increased.
[0026]
Further, according to the invention of claims 5 to 9 of the present application, the rigidity of the
diaphragm is enhanced by adhering the reinforcing member along the minor axis direction of the
diaphragm or providing an arcuate rib.
[0027]
Further, according to the invention of claims 10 to 14 of the present application, the stiffness of
the vibration system is lowered by providing the damper parallel to the edge or parallel to the
minor axis direction of the diaphragm.
[0028]
Further, according to the invention of claim 15 of the present application, the width of the edge
is made wider in the portion where the radius of curvature of the outer periphery of the
diaphragm becomes smaller.
As a result, the stiffness of the edge is lowered, and the bass range can be reproduced.
[0029]
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A loudspeaker according to a first
embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a block diagram of a speaker having an elongated structure in the first embodiment, (a)
is a plan view, (b) is a cross-sectional view in the major axis direction, and (c) is a cross-sectional
view in the minor axis direction.
In this figure, the diaphragm 1a is a substantially elliptical diaphragm, and as shown in FIGS. 1
(b) and 1 (c), it is non-axisymmetric (non-rotationally symmetric) having a major axis direction
and a minor axis direction. , Have a bulge in the direction of vibration.
The edge 3a is joined to the outer peripheral portion of the diaphragm 1a and is held by the
frame 11a.
[0030]
The edge 3a is made of a material excellent in elasticity, is a member having an arc-shaped cross
section, and is formed in a band shape along the outer periphery of the diaphragm 1a.
Unlike the conventional speaker, a voice coil bobbin 6a having the same contour as that of the
outer peripheral portion of the diaphragm 1a is fixed to the diaphragm 1a.
The voice coil bobbin 6a has a sheet-like member formed in a band shape along the outer
periphery of the diaphragm 1a. The upper end of the voice coil bobbin 6a is bonded to the
diaphragm 1a, and a voice coil not shown is wound around the lower end.
[0031]
The frame 11a is formed in a box shape, and the side surface thereof is bent in an oval shape
along the edge 3a, and the bottom surface is formed in an oval plate shape.
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A yoke 8a, a magnet 9a and a plate 10a for constituting the magnetic circuit 21 are attached to
the bottom of the frame 11a.
The yoke 8a is a box-shaped magnetic body like the frame 11a, and its cross-sectional shape is Ushaped in both the short axis direction and the long axis direction.
The magnet 9a attached to the upper portion of the bottom surface of the yoke 8a is elliptical as
in the planar shape of the diaphragm 1a.
The plate 10a is also referred to as a center plate, and is a member that generates a magnetic
flux in an air gap facing the inner peripheral portion of the side surface of the yoke 8a and is
made of a magnetic material.
Here, the planar shape of the plate 10a is slightly smaller than the side inner periphery of the
yoke 8a.
[0032]
In the speaker configured as described above, since the diaphragm 1a has a bulge in the central
axis direction, the rigidity of the diaphragm 1a is improved.
Furthermore, since the entire diaphragm 1a integrally receives the driving force, the split
resonance in the long axis direction is less likely to be excited, and flat frequency characteristics
can be obtained in the middle and high frequencies.
Furthermore, since the wire length L of the voice coil can be made considerably longer than the
conventional speaker shown in FIG. 16 and the volume of the magnet 9a can be increased, the
driving force is increased and the conversion efficiency can be enhanced.
In the present embodiment, the planar shape of the diaphragm 1a and the magnetic circuit 21 is
elliptical, but the shape is not limited to this.
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[0033]
Next, a loudspeaker according to a second embodiment of the present invention will be described
with reference to FIGS.
2A and 2B are diagrams showing the structure of the loudspeaker according to the second
embodiment (part 1), wherein FIG. 2A is a plan view, FIG. 2B is a sectional view in the major axis
direction, and FIG. 2C is a sectional view in the minor axis direction. And has doubled.
In FIG. 2, the diaphragm 1b is a substantially track-shaped diaphragm that generates air
vibration, and as shown in FIGS. 2 (b) and 2 (c), it is non-axisymmetric with a major axis direction
and a minor axis direction. It has a semi-cylindrical bulge in the direction of vibration. And the
edge 3b is joined to the outer peripheral part of the diaphragm 1b, and it is hold | maintained at
the flame | frame 11b.
[0034]
Similar to the first embodiment, the edge 3 b is a member having an arc shape in cross section,
and is formed in a band shape along the outer periphery of the diaphragm 1 b. Further, a voice
coil bobbin 6b having the same contour as that of the outer peripheral portion of the diaphragm
1b is fixed to the diaphragm 1b. The shape of the voice coil bobbin 6b is a sheet-like member
formed in a band along the outer periphery of the diaphragm 1b. The diaphragm 1b is adhered
to the upper end thereof, and a voice coil (not shown) is wound around the lower end. Ru.
[0035]
The frame 11b is formed in a box shape, and the side surface thereof is bent in a rectangular
shape along the edge 3b, and the bottom surface is in a rectangular shape. A yoke 8b, a magnet
9b and a plate 10b for constituting the magnetic circuit 22 are attached to the bottom of the
frame 11b. The magnet 9b attached to the upper surface of the bottom of the yoke 8b is
magnetized in the central axis direction of the diaphragm 1b.
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[0036]
In the speaker configured as described above, since the voice coil bobbin 6b is integrally driven
as in the first embodiment, split resonance in the major axis direction of the diaphragm 1b is not
easily excited. FIG. 3 shows the frequency characteristics of the loudspeaker of this embodiment
measured under the same conditions as FIG. Here, compared to the characteristics of FIG. 17, it
can be seen that the peak dip in the middle and high regions is eliminated, and a flat frequency
characteristic is obtained in the middle and high regions. The lowest resonance frequency f0 is
180 Hz in FIG. 17, whereas it is greatly reduced to 100 Hz in FIG. 3, so that the bass range can
be reproduced more. Furthermore, since the magnetic circuit 22 has a linear shape, manufacture
of members constituting the magnetic circuit becomes easy, and mass productivity is excellent.
[0037]
FIG. 4 is a view showing the configuration of the speaker (part 2) in the second example of this
embodiment, (a) is a plan view, (b) is a cross-sectional view in the major axis direction, and (c) is
the minor axis direction Is a cross-sectional view of FIG. The same parts as those of the speaker
in FIG. As shown in FIG. 4C, the magnetic circuit 23 is divided into two groups in the short axis
direction. The magnetic circuit 23 comprises a yoke 8c having a U-shaped cross section, and a
magnet 9c attached to one of both side surfaces of the yoke 8c closer to the central axis of the
diaphragm 1b. The magnet 9c is smaller than that shown in FIG. 2C, and is magnetized in the
direction orthogonal to the central axis of the diaphragm 1b.
[0038]
The speaker configured in this way is different in the configuration of the speaker and the
magnetic circuit in FIG. 2, but the operation and the effect thereof are the same. Although the
speaker in the second embodiment has a track shape as the planar shape of the diaphragm 1b
and the voice coil bobbin b, the shape is not limited to this. For example, as shown in FIG. 5, the
case of having an L-shaped diaphragm 1c, an edge 3c, a magnetic circuit 24, and a frame 11c can
be considered, and a novel design which can not be found in conventional speakers is possible.
Also, the magnetic circuit is not limited to that of the above embodiment, and the air gap may
have a linear shape. The shape of the diaphragm is not limited to that of the above embodiment,
and may be, for example, a flat diaphragm.
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[0039]
Next, a loudspeaker according to a third embodiment of the present invention will be described
with reference to FIG. FIG. 6 is a perspective view showing the structure of the voice coil bobbin
6c of the speaker of the third embodiment, and the other structure is the same as that of the
speaker of the second embodiment. The shape of the voice coil bobbin 6c as viewed from the
central axis direction is the same as that shown in FIG. 2A, and is a non-axisymmetric shape
having a major axis direction and a minor axis direction. However, unlike the second
embodiment, a fold 31 is integrally formed on the upper portion of the voice coil bobbin 6c.
[0040]
The elongated voice coil bobbin has a property of being more easily deformed in its short
diameter direction than a circular one. When the voice coil bobbin is deformed carelessly during
the assembly of the speaker, defects such as gap (air gap) rubbing may be caused. However, in
the present embodiment, since the folds 31 are provided, the rigidity of the voice coil bobbin 6c
is increased, and the voice coil bobbin 6c is resistant to deformation. In addition, the assembly of
the speaker becomes easy, and the occurrence of defects can be prevented.
[0041]
The shape of the voice coil bobbin 6c is not particularly limited as shown in FIG. Also, the same
effect can be obtained by forming or bonding a rib having a similar shape instead of the fold 31.
[0042]
Next, a loudspeaker according to a fourth embodiment of the present invention will be described
with reference to FIG. FIG. 7 is a perspective view showing the configuration of a magnetic circuit
25 and a voice coil bobbin which are drive parts of the speaker according to the fourth
embodiment. The other parts including the diaphragm and the frame are the same as the speaker
of the second embodiment. Unlike the first to third embodiments, the magnetic circuit 25 is
provided separately in the direction of the major axis of the diaphragm.
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[0043]
As shown in FIG. 7 (b), one magnetic circuit 25 is composed of a yoke 8d, a magnet 9d, and a
plate 10d. The yoke 8d is a magnetic body formed in a groove shape, and its cross-sectional
shape is U-shaped in the short axis direction. The magnet 9d attached to the top of the bottom of
the yoke 8d is a rectangular parallelepiped magnet magnetized in a direction parallel to the
central axis of the diaphragm. The plate 10d is a member that generates a magnetic flux in an air
gap opposed to the side inner peripheral portion of the yoke 8d, and is made of a magnetic
material. For example, three sets of such magnetic circuits 25 are provided in the major axis
direction of the diaphragm.
[0044]
On the other hand, as shown in FIG. 7A, the reinforcing member 7 is fixed to the voice coil
bobbin 6d. The shape of the voice coil bobbin 6d is the same as that shown in FIG. The
reinforcing member 7 is, for example, a rectangular plate-like member made of paper, and is
adhered to the voice coil bobbin 6 d so as to be located between the adjacent magnetic circuits
25.
[0045]
In the speaker having such a structure, as in the third embodiment, the voice coil bobbin 6d is
not easily deformed, which facilitates the assembly of the speaker and can prevent the
occurrence of the assembly failure. The shapes of the voice coil bobbin 6d and the magnetic
circuit 25, and the number of the reinforcing members 7 and the magnetic circuit 25 are not
particularly limited as shown in FIG.
[0046]
Next, a loudspeaker according to a fifth embodiment of the present invention will be described
with reference to FIGS. 8 and 9. FIG. FIG. 8 is a perspective view showing the configuration of a
diaphragm 1 d in the speaker of the fifth embodiment. The diaphragm 1d is the same as that
shown in FIG. 2, and the cross-sectional shape in the minor axis direction is formed in a
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semicircular shape, and is uniform in the major axis direction except its end. The end of the end
is spherically curved with respect to the edge.
[0047]
A plurality of reinforcing members 2 are attached to the inner surface of the diaphragm 1d. The
reinforcing member 2 is a semicircular plate-like member, the edge of which is adhered to the
diaphragm 1 d via an adhesive.
[0048]
When the rigidity of the diaphragm is insufficient, a resonance mode may be generated in the
short diameter direction from a low frequency, and non-linear distortion may be generated due
to bending vibration. In the graph shown in FIG. 9, the graph indicated by the broken line A is the
frequency of the second harmonic distortion when the paper is used for the diaphragm 1b of the
speaker in FIG. 2 and the weight is 0.6 g without using a reinforcing member. It shows the
characteristics. The measurement conditions are the same as in the case of FIG. In this case, it
can be seen that high distortion occurs at around 630 Hz and 1740 Hz due to the insufficient
rigidity of the diaphragm.
[0049]
The graph shown by the solid line B in FIG. 9 shows the frequency characteristics of second
harmonic distortion when the reinforcing member 2 is bonded to the back side of the diaphragm
1 d. As shown in the figure, for example, harmonic distortion at a frequency of 100 Hz or more is
significantly reduced, the occurrence of the resonance mode is suppressed, and the distortion
level is reduced by 10 dB or more.
[0050]
Although the case where the reinforcing member 2 is adhered to the back side of the diaphragm
1d has been described in this embodiment, it is apparent that the same effect can be obtained by
adhering to the front side of the diaphragm. Further, instead of bonding the reinforcing member
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2 to the diaphragm 1d, the same effect can be obtained by forming a diaphragm having ribs by
using the diaphragm and the reinforcing member as the same material.
[0051]
Next, a loudspeaker according to a sixth embodiment of the present invention will be described
with reference to FIGS. FIG. 10 is a perspective view showing a configuration of a diaphragm 1b
and a support system in the speaker (part 1) of the sixth embodiment. The diaphragm 1b is a
diaphragm having the same shape as that shown in FIG. 2 and is vibratably held by the frame
11d via an edge 3b fixed to the outer peripheral portion thereof.
[0052]
The diaphragm 1b of this embodiment is different from that of the second embodiment, and is
also held by the damper 4a via the connecting member 5a. The connecting member 5a is a platelike member whose upper portion is formed in a semicircular shape and whose lower portion is
formed in a rectangular shape, and a plurality of the connecting members 5a are attached in the
longitudinal direction of the diaphragm 1b. Further, the lower end portion of the connecting
member 5a is fixed to the damper 4a, so that the connecting member 5a can be vibrated
integrally with the diaphragm 1b. The tamper 4a has the other end fixed to the frame as in the
conventional speaker. The damper 4a of this embodiment has a short length along the frame and
is provided with one pair for each connecting member 5a. In the loudspeakers of the first to fifth
embodiments, although the damper was not clarified, it is assumed that the damper is normally
provided. However, like the tweeter for high-pitched sound reproduction, when the amplitude of
the diaphragm is small, the damper is not necessary.
[0053]
Now, in the conventional loudspeaker as shown in FIG. 16, a force acts on the circumferential or
elliptical circumferential damper in the circumferential direction along with the vertical
movement. In particular, the stiffness of dampers with narrow widths increases. On the other
hand, since the damper 4a of this embodiment is linear, such a force does not work, and the
stiffness can be reduced. As a result, the lowest resonance frequency f0 can be suppressed to a
low level, and the bass range can be reproduced.
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[0054]
The configuration of the support system is not limited to this embodiment, and other
configurations can be considered, and the same effect is obtained. FIG. 11 is a perspective view
showing a configuration of a diaphragm 1b and a support system in the speaker (part 2) of the
sixth embodiment. Here, the damper 4b is attached in parallel with the minor axis direction of
the diaphragm 1b. The other configuration including the diaphragm 1b is the same as that shown
in FIG.
[0055]
FIG. 12 is a perspective view showing a configuration of a diaphragm 1b and a support system in
the speaker (part 3) of the sixth embodiment. In the figure, the damper 4c is mounted above the
diaphragm 1b via the mounting member 12a. The mounting member 12a is a member formed in
a U-shape, and the lower end portion thereof is fixed to the frame 11d. Then, one end of the
damper 4c is fixed to the upper surface of the mounting member 12a, and the connecting
member 5c is held at the inner end of the damper 4c. The other configuration including the
diaphragm 1b is the same as that shown in FIG.
[0056]
Further, FIG. 13 is a perspective view showing a configuration of a diaphragm 1b and a support
system in the speaker (part 4) of the sixth embodiment. In the drawing, the damper 4d is
mounted above the diaphragm 1b as a set of two mounting members 12b. Unlike the one shown
in FIG. 12, the mounting member 12b is mounted on the frame 11d so as to straddle the front
edge 3b and the facing edge 3b. One end of the damper 4d is fixed to the upper surface of the
two mounting members 12b, and the connecting member 5d is held at the center line of the
damper 4d. The shape of the connecting member 5d is the same as that shown in FIG. The other
configuration including the diaphragm 1b is the same as that shown in FIG.
[0057]
In the sixth embodiment, as the diaphragm 1b and the edge 3b, the same one as the speaker
shown in FIG. 2 is used, but the shape is not limited to this.
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[0058]
Next, a loudspeaker according to a seventh embodiment of the present invention will be briefly
described with reference to FIG.
FIG. 14 is a perspective view showing the configuration of the loudspeaker of the seventh
embodiment. The diaphragm 1b and the components (edge 3b, damper 4a, connection member
5a, frame 11d) of the support system are the same as in the sixth embodiment, and the
description thereof is omitted. In the present embodiment, the connecting member 5a is fixed to
the diaphragm 1b and also fixed to the voice coil bobbin 6d. In this way, the effects of both the
embodiments can be obtained without increasing the number of parts.
[0059]
Finally, a loudspeaker according to an eighth embodiment of the present invention will be
described with reference to FIG. FIG. 15 is a plan view of a diaphragm 1b and an edge 3d
constituting the speaker of the eighth embodiment. As shown in the drawing, the planar shape of
the diaphragm 1b is a track shape as in the case shown in FIG. 18, and the edge 3d is attached
along the outer periphery thereof. The dimension of the edge 3d is, for example, 5 mm wide in
the straight line portion, but the width is wide in the portion where the curvature radius of the
diaphragm 1b is small, and is at most 12.5 mm.
[0060]
On the other hand, in the edge 3f of the conventional example of FIG. 18, the width is 5 mm
regardless of the radius of curvature of the outer periphery of the diaphragm 1b. In the case of
the edge 3 f of FIG. 18, a circumferential direction force acts on the curved portion along with
the up and down movement thereof, so the stiffness becomes larger than that of the straight
portion. For example, when this edge is made of a 0.25 mm thick cloth, the stiffness per cm of
the curved portion is calculated to be 100 N / m, and the stiffness per cm of the linear portion is
calculated to be 36 N / m, and the entire edge is The influence of the curve part is large on the
increase of the stiffness of the Therefore, by widening only the curved portion of the edge 3d as
shown in FIG. 15, the stiffness of the edge 3d can be reduced to some extent without changing
the width of the speaker.
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[0061]
The stiffness of the edge 3f of FIG. 18 is 1190 [N / m], whereas the edge of this embodiment is
920 [N / m]. As a result, the lowest resonance frequency f0 is lowered by 12%, and the bass can
be reproduced more. Although the track-shaped diaphragm and the edge are described in the
present embodiment, the present invention is not particularly limited to this shape.
[0062]
As described above, according to the invention of claims 1 to 4 of the present application, by
making the shape of the voice coil bobbin the same non-axisymmetric shape as the diaphragm,
the whole vibration system vibrates integrally. Therefore, split resonance in the major axis
direction of the diaphragm is less likely to occur, and flat sound pressure frequency
characteristics can be obtained in the middle and high frequencies. Furthermore, the wire length
of the voice coil can be made considerably longer than that of the conventional one, and the
volume of the magnet can be increased, so that the electromagnetic driving force of the
diaphragm becomes large. As a result, an effect of improving the electroacoustic conversion
efficiency occurs.
[0063]
According to the invention of claims 5 to 9 of the present application, the rigidity of the
diaphragm is enhanced by providing a reinforcing member for the diaphragm or providing an
arcuate rib along the minor axis direction of the diaphragm. As a result, the resonance mode in
the minor axis direction of the diaphragm is less likely to occur, and a reproduced sound with
less distortion can be obtained.
[0064]
Further, according to the invention of claims 10 to 14 of the present application, by providing
the damper on the outer peripheral portion of the diaphragm, the stiffness of the vibration
system can be suppressed to a low level as compared with the conventional speaker unit. This
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makes it possible to further reproduce the low tone range.
[0065]
Furthermore, according to the invention of claim 15 of the present application, by providing the
edge where the width is wide in the portion where the radius of curvature of the diaphragm is
reduced, the stiffness of the edge can be suppressed low compared to the conventional speaker
unit. This makes it possible to further reproduce the low tone range.
[0066]
As described above, when the speaker of the present invention is attached to a landscape type
television, the width of the television set is not wide, and sound with excellent sound quality can
be output together with the image.
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