JPH07222280

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DESCRIPTION JPH07222280
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker used in various audio equipment.
[0002]
2. Description of the Related Art In recent years, high-quality sources (CD, DAT, etc.) over the
entire audio band have been put to practical use by digitization of audio equipment, but there are
still many distortions in speakers that convert music signals into audio output. Has occurred.
Distortion generated in the above speaker can be roughly classified into two types, distortion
generated by the speaker itself in electro-acoustic conversion (strain by drive system and support
system), and shape in the vicinity of the speaker after electro-acoustic conversion And the
distortion generated acoustically. If the support system has a shape with good linearity in order
to reduce the distortion of the former, the structure becomes relatively large with respect to the
diaphragm, and the wave front of the sound from the diaphragm is disturbed, resulting in an
increase of distortion of the latter. Therefore, it was the fact that no effective improvement
method was found.
[0003]
Hereinafter, the conventional speaker will be described with reference to the drawings. FIG. 2 is a
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half sectional view showing a configuration of a speaker using a flat diaphragm among the
conventional speakers, and a lower plate 1 having a center pole 7, a ring-shaped magnet 2, and a
ring-shaped upper plate 3 are shown. A magnetic circuit is formed by coupling to form a
magnetic gap 8. The baffle plate 4 is coupled to this magnetic circuit, and the peripheral portion
of the edge 10 coupled to the peripheral portion of the diaphragm 5 in which the voice coil 6 is
coupled to the central lower portion is fixed to the upper inner peripheral portion side of the
baffle plate 4 , And the voice coil 6 is fitted in the magnetic gap 8.
[0004]
When current flows through the voice coil 6 inserted in the magnetic gap 8 of the conventional
speaker configured as described above, the magnetic flux in the magnetic gap 8 causes the voice
coil 6 to move up and down according to the left-hand rule of Fleming. By acting in a direction
and driving the diaphragm 5 to which the voice coil 6 is coupled, a sound wave is generated to
perform electro-acoustic conversion.
[0005]
However, in the above-described conventional configuration, when current flows through the
voice coil 6 and the diaphragm 5 receives the driving force and moves in the vertical direction,
the upper and lower sides of the edge 10 holding the diaphragm 5 are moved. Since the reaction
force to the driving force of the voice coil 6 in the direction is different, the amount of amplitude
of the diaphragm 5 is different in the vertical direction.
Further, since the relationship between the displacement of the diaphragm 5 and the reaction
force of the edge 10 at that time is not proportional, the amplitude of the diaphragm 5 is not
proportional to the current flowing through the voice coil 6, and the support system Phenomena
called nonlinearity and asymmetry occur. Due to these factors, the resulting acoustic output has
the problem of becoming distorted.
[0006]
Further, when the diaphragm 5 is divided and resonated in the high region, only the outer
peripheral portion of the diaphragm 5 is held by the edge 10 so that the diaphragm 5 easily
resonates, generating very large disturbance of the acoustic output characteristic. It will Further,
the sound wave generated from the diaphragm 5 is disturbed in the wave front by the edge 10,
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and the obtained acoustic output is also disturbed in the high frequency characteristic although
the diaphragm 5 is not divided and resonated. I had it.
[0007]
It is an object of the present invention to solve such problems and to provide a speaker having
excellent distortion-free sound output characteristics.
[0008]
SUMMARY OF THE INVENTION In order to solve the above problems, the speaker according to
the present invention joins a diaphragm to which a voice coil is connected to a cushion made of
urethane foam or foam rubber, and further, this cushion is an upper surface of a magnetic circuit.
Bonded to the
[0009]
According to this configuration, the voice coil fixed to the diaphragm coupled with the cushion
can be held in the magnetic gap.
When the current flows through the voice coil and the diaphragm vibrates in the vertical
direction, the reaction force proportional to the displacement of the diaphragm is compressed
and expanded by the magnetic circuit to which the cushion is fixed and the moving diaphragm. It
can be applied to the diaphragm to improve the non-linearity and asymmetry of the support
system.
[0010]
Further, since the cushion is fixed to most of one side of the diaphragm, when the diaphragm is
divided and resonated in the high frequency band, the cushion damps the resonance of the
diaphragm and the high frequency acoustic output characteristics are flattened.
Furthermore, since there is no convexity of the cushion in the same plane as the diaphragm or a
concave of the cushion in the same plane as the diaphragm, the wave front of the sound wave
from the diaphragm is not disturbed. Therefore, the obtained sound output characteristic is low
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distortion and little disturbance over the high frequency band.
[0011]
An embodiment of the present invention will be described below with reference to the drawings.
The same reference numerals are given to parts having the same configuration as the
conventional example.
[0012]
FIG. 1 is a half sectional view showing the configuration of a loudspeaker according to an
embodiment of the present invention, in which a lower plate 1 having a center pole 7, a ring
magnet 2 and a ring upper plate 3 are stacked and coupled , And a magnetic circuit in which the
magnetic gap 8 is formed. The baffle plate 4 is coupled to the upper surface of this magnetic
circuit, and the voice coil 6 is coupled to the central lower portion on the inner peripheral side of
the baffle plate 4, and urethane foam or the like on the inner peripheral side and the outer
peripheral side of the voice coil 6. A voice coil 6 is fitted in the magnetic gap 8 together with a
diaphragm 5 to which a cushion 9 made of foam rubber is joined. At this time, the lower surface
of the cushion 9 is joined to the upper portion of the center pole 7 and the upper portion of the
upper plate 3. The cushion 9 is shaped to fill the space between the inner peripheral side of the
baffle plate 4 and the outer peripheral side of the diaphragm 5, and the heights of the diaphragm
5, the cushion 9, and the baffle plate 4 are the same. .
[0013]
In the speaker of the present invention configured as described above, when current flows
through the voice coil 6 and the diaphragm 5 vibrates in the vertical direction, compression and
expansion are performed by the magnetic circuit to which the cushion 9 is fixed and the moving
diaphragm 5. Thus, a reaction force proportional to the displacement of the diaphragm 5 can be
applied to the diaphragm 5 in the vertical direction. In addition, since the cushion 9 is fixed to
most of one side of the diaphragm 5 and the diaphragm 5 resonates in the high region, the
cushion 9 damps the resonance of the diaphragm 5 and the acoustic output characteristic of the
high region Flattened. Furthermore, since there is no protrusion of the cushion 9 which is
coplanar with the diaphragm 5 and no dent of the cushion 9 which is coplanar with the
diaphragm 5, the wave front of the sound wave from the diaphragm 5 is not disturbed.
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[0014]
As described above, when the current flows through the voice coil and the diaphragm vibrates in
the vertical direction, the speaker according to the present invention is compressed and
expanded by the magnetic circuit to which the cushion is fixed and the moving diaphragm. The
reaction force proportional to the displacement of the diaphragm can be applied to the
diaphragm, and the movement of the diaphragm is proportional to the current flowing to the
voice coil, and the non-linearity and asymmetry of the support system are improved, resulting in
The acoustic output characteristics that are produced are low distortion.
[0015]
Further, since the cushion is fixed to most of one side of the diaphragm, when the diaphragm is
divided and resonated in the high frequency band, the cushion damps the resonance of the
diaphragm and the high frequency acoustic output characteristics are flattened.
Furthermore, since there is no convexity of the cushion in the same plane as the diaphragm or a
concave of the cushion in the same plane as the diaphragm, the wave front of the sound wave
from the diaphragm is not disturbed. Therefore, the obtained sound output characteristic is low
distortion and little disturbance over the high frequency band.
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