JP2012080530

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DESCRIPTION JP2012080530
In an electrostatic electroacoustic transducer, when used as an electrostatic speaker, sound
generated by a vibrating body is easily radiated to the outside, and when used as an electrostatic
microphone. Makes it easy to convert externally generated sound into an acoustic signal.
SOLUTION: Electrodes 20U and 20L are located on both sides of an air-permeable separating
member 10, and elastic members 30U and 30L having elasticity and insulation are located
outside the electrodes 20U and 20L. Then, on the outer side of the elastic members 30U and
30L, the vibrators 40U and 40L in which the conductive film is formed on the surface of the
insulating film are located. The electrode 20U and the electrode 20L are configured to be less
likely to be displaced by an external force as compared to the vibrating body 40. [Selected figure]
Figure 1
Electrostatic transducer
[0001]
The present invention relates to an electrostatic electroacoustic transducer.
[0002]
The electrostatic speaker disclosed in Patent Document 1 includes two flat electrodes facing each
other at intervals and a conductive diaphragm (a vibrator having a conductive member disposed
between the two flat electrodes). When a predetermined bias voltage is applied to the diaphragm
and the voltage applied to the flat electrode is changed, the electrostatic attractive force acting
on the diaphragm is changed, whereby the diaphragm is displaced. Do.
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If this applied voltage is changed according to the acoustic signal to be input, the diaphragm
repeats displacement accordingly, and acoustic waves corresponding to the acoustic signal are
generated from both sides of the diaphragm. Then, the generated acoustic wave is radiated to the
outside through the through hole opened in the flat electrode. Further, according to Patent
Document 2, in a speaker element in which a plurality of fixed electrodes are disposed to face
each other with a diaphragm (oscillator) interposed therebetween, polarization voltages of
opposite polarities are applied to adjacent diaphragms, A technique is disclosed that generates a
large sound pressure by applying a drive signal of reverse polarity between fixed fixed
electrodes.
[0003]
JP, 2007-318554, A JP, 06-209499, A
[0004]
In the electrostatic loudspeaker having the above-described configuration, sound waves
generated from the diaphragm facing the flat electrode pass through the through holes provided
in the flat electrode and are radiated to the outside of the electrostatic loudspeaker.
Therefore, when the aperture ratio of the flat electrode is small, the sound wave generated from
the diaphragm facing the flat electrode passes through the through hole and the outside of the
electrostatic speaker compared to the case where the aperture ratio of the flat electrode is large.
There is a problem that the sound pressure outside the electrostatic speaker is low because the
rate of radiation to the air is low. Moreover, it is also possible to use the structure of this
electrostatic speaker as a structure of an electrostatic microphone. In this case, a sound (sound)
is converted into an acoustic signal (electric signal) by allowing a sound wave generated outside
to pass through a through hole provided in the electrode to vibrate the diaphragm. Therefore,
when the aperture ratio of the electrode is small, the sound wave generated outside is less likely
to pass through the through hole and the acoustic signal converted by the electrostatic
microphone becomes smaller than when the aperture ratio of the electrode is large There is a
problem that the sensitivity of the electrostatic microphone is lowered.
[0005]
In order to solve the above problems, the present invention is an electrostatic electroacoustic
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transducer, when used as an electrostatic speaker, the sound generated by the vibrating body is
easily radiated to the outside, and the electrostatic type When used as a microphone, the object is
to make it easy to convert externally generated sound into an acoustic signal.
[0006]
In order to solve the problems described above, the present invention comprises a separating
member having air permeability and insulating properties, a pair of electrodes having a through
hole penetrating from the front surface to the rear surface and sandwiching the separating
member, and at least one of them. A conductive film formed on the entire surface of the surface,
and positioned between the electrode and the vibrator, and a pair of vibrators facing each other
across the spacing member and the pair of electrodes; An electrostatic electroacoustic transducer
characterized by comprising an elastic member having elasticity and air permeability.
[0007]
In the present invention, the conductive film included in the vibrator may be electrically
connected to the ground of a drive circuit that supplies an acoustic signal to the electrode.
Further, in the present invention, the pair of electrodes may be higher in rigidity than the pair of
vibrators.
[0008]
According to the present invention, in the electrostatic type electroacoustic transducer, when
used as an electrostatic type speaker, the sound generated by the vibrator is easily radiated to
the outside, and is used as an electrostatic type microphone. In this case, the externally generated
sound is likely to be converted into an acoustic signal.
[0009]
FIG. 1 is an external view of an electrostatic speaker according to an embodiment of the present
invention.
It is the sectional view on the AA line of the electrostatic-type speaker of FIG.
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It is an external view of an electrode. It is the figure which showed the electric constitution of the
electrostatic-type speaker. It is a figure which shows operation ¦ movement of an electrostatic
type speaker. It is an external view of the electrostatic-type speaker which concerns on the
modification of this invention. It is a figure which illustrates the field to which the adhesive
concerning a modification of the present invention was applied. It is an external view of the
electrostatic-type speaker which concerns on a modification. It is the figure which expanded a
part of upper surface of the electrostatic-type speaker which concerns on a modification. It is the
figure which showed the front and side of the clip concerning a modification. It is the figure
which showed the state which pinched ¦ interposed the electrostatic type speaker by the clip
which concerns on a modification. It is an external view of the electrostatic-type speaker which
concerns on a modification. It is a figure showing the electric composition of the electrostatic
type microphone concerning a modification.
[0010]
Embodiment In this embodiment, an example in which an electrostatic electroacoustic transducer
is applied as an electrostatic speaker that converts an acoustic signal (electric signal) into sound
(sound) will be described. FIG. 1 is an external view of an electrostatic speaker 1 according to an
embodiment of the present invention, and FIG. 2 is a cross-sectional view of the electrostatic
speaker 1 of FIG. FIG. 3 is an external view of the electrode 20. In these figures, the directions are
indicated by the orthogonal X, Y, and Z axes, and the horizontal direction when the electrostatic
speaker 1 is viewed from the front is the X axis direction, the depth direction is the Y axis
direction, and the height is high. The longitudinal direction is the Z-axis direction. Further, in the
drawings, those in which • is described in o means an arrow directed from the back to
the front of the drawing. Further, in the drawings, those in which x is described in o
means an arrow directed from the front to the back of the drawing. Here, front is a
representation of the direction of the surface for the sake of convenience, and does not represent
that it faces in the front direction when the electrostatic speaker 1 is disposed. The electrostatic
speaker 1 may be arranged in any orientation when necessary. Also, the dimensions of each
component in the figure are different from the actual dimensions so that the shape of the
component can be easily understood.
[0011]
(Configuration of Each Part of Electrostatic Speaker 1) The configuration of each part
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constituting the electrostatic speaker 1 will be described. The electrostatic speaker 1 includes a
spacing member 10, electrodes 20U and 20L, elastic members 30U and 30L, vibrators 40U and
40L, and surface members 50U and 50L. In the present embodiment, the configurations of the
electrodes 20U and 20L are the same, and the configurations of the elastic members 30U and
30L are the same. Further, the configurations of the vibrating bodies 40U and 40L are the same,
and the configurations of the surface members 50U and 50L are the same. Therefore, when it is
not necessary to distinguish between the respective members, reference numerals "U" and "L The
description of "is omitted.
[0012]
The spacing member 10 is a non-woven fabric and can pass air and sound without passing
electricity. The spacer 10 is elastic and deforms when an external force is applied, and returns to
its original shape when an external force is removed. The spacing member 10 has a rectangular
shape when viewed from the Z-axis direction. The dimension of the separating member 10 in the
Z-axis direction is preferably about 1 mm. The dimension in the Z-axis direction of the separating
member 10 is not limited to about 1 mm, and may be appropriately determined according to the
voltage applied to the electrodes 20U and 20L.
[0013]
The electrode 20 is a so-called punching metal, which is higher in rigidity (larger in Young's
modulus) than the vibrating body 40, and has a plurality of through holes 21 penetrating from
the surface to the back surface of the conductive metal plate. The electrode 20 has a rectangular
shape when viewed from the Z-axis direction, the dimension in the X-axis direction is the same as
the dimension in the X-axis direction of the separating member 10, and the dimension in the Yaxis direction is Y of the separating member 10. It is the same as the axial dimension. The
number of through holes 21 formed in the electrode 20 is not limited to the number shown in
FIG.
[0014]
The elastic member 30 is a non-woven fabric and can pass air and sound without conducting
electricity. The elastic member 30 has elasticity, and deforms when an external force is applied,
and returns to its original shape when an external force is removed. The elastic member 30 has a
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rectangular shape when viewed from the Z-axis direction, the dimension in the X-axis direction is
the same as the dimension in the X-axis direction of the spacing member 10, and the dimension
in the Y-axis direction is the spacing member It is the same as the dimension of 10 in the Y-axis
direction.
[0015]
The vibrating body 40 is based on a film of a synthetic resin having insulation and flexibility such
as PET (polyethylene terephthalate: polyethylene terephthalate) or PP (polypropylene:
polypropylene), and a metal having conductivity on one side of the film The conductive film is
formed by vapor deposition. The vibrating body 40 has a rectangular shape when viewed from
the Z-axis direction, the dimension in the X-axis direction is the same as the dimension in the Xaxis direction of the separating member 10, and the dimension in the Y-axis direction of the
separating member 10. It is the same as the dimension in the Y-axis direction. Moreover, it is
preferable that the dimension of the Z-axis direction of the vibrating body 40 is about 3
micrometers-10 micrometers.
[0016]
The surface member 50 is a woven cloth, has insulation and flexibility, and allows the passage of
air and sound. The surface member 50 has a rectangular shape when viewed from the Z-axis
direction, the dimension in the X-axis direction is the same as the dimension in the X-axis
direction of the spacing member 10, and the dimension in the Y-axis direction of the spacing
member 10. It is the same as the dimension in the Y-axis direction. The surface member 50
preferably has a dimension in the Z-axis direction of less than 12 μm and a large aperture ratio.
[0017]
(Structure of Electrostatic Speaker 1) Next, the structure of the electrostatic speaker 1 will be
described. The spacer 10 is disposed between the lower surface of the electrode 20U and the
upper surface of the electrode 20L. The spacing member 10 is coated with an adhesive with a
width of several mm from the edge in the X-axis direction and the edge in the Y-axis direction
and is fixed to the electrode 20U and the electrode 20L, and is inside from the adhesive applied
portion Is not fixed to the electrode 20U and the electrode 20L.
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[0018]
The elastic member 30U is coated with an adhesive with a width of several mm from the edge in
the X-axis direction and the edge in the Y-axis direction, and is fixed to the upper surface of the
electrode 20U. It is in a state of not being fixed to the electrode 20U. The elastic member 30L is
coated with an adhesive with a width of several mm from the edge in the X-axis direction and the
edge in the Y-axis direction and is fixed to the lower surface of the electrode 20L. It is in a state
of not being fixed to the electrode 20L.
[0019]
The vibrating body 40U is coated with an adhesive with a width of several mm inward from the
edge in the X-axis direction and the edge in the Y-axis direction and is fixed to the upper surface
of the elastic member 30U. Is not fixed to the elastic member 30U. The vibrating body 40L is
coated with an adhesive with a width of several mm from the edge in the X-axis direction and the
edge in the Y-axis direction, and is fixed to the lower surface of the elastic member 30L. Is not
fixed to the elastic member 30L. The surface on which the conductive film is formed is in contact
with the elastic member 30U, and the surface on which the conductive film is formed is in
contact with the elastic member 30L.
[0020]
The surface member 50U is coated with an adhesive with a width of several mm inward from the
edge in the X-axis direction and the edge in the Y-axis direction and is fixed to the upper surface
of the vibrating body 40U, and is inside from the adhesive applied portion Is not fixed to the
vibrator 40U. The surface member 50L is coated with an adhesive with a width of several mm
from the edge in the X-axis direction and the edge in the Y-axis direction, and is fixed to the
lower surface of the vibrating body 40L. Is not fixed to the vibrator 40L.
[0021]
(Electrical Configuration of Electrostatic Speaker 1) Next, the electrical configuration of the
electrostatic speaker 1 will be described. FIG. 4 is a diagram showing an electrical configuration
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of the electrostatic speaker 1. The drive unit 100 is connected to the electrostatic speaker 1. The
drive unit 100 includes a transformer 110, an amplifier 120, and a bias power supply 130. An
acoustic signal (electrical signal) is input to the amplifier 120. The amplifier 120 is an
amplification circuit that amplifies the input acoustic signal and outputs the amplified acoustic
signal. The amplifier 120 has terminals TA1 and TA2 for outputting an acoustic signal, and the
terminal TA1 is connected to the terminal T1 on the primary side of the transformer 110 via the
resistor R1. The terminal TA2 is connected to the other terminal T2 of the primary side of the
transformer 110 via the resistor R2. The terminal T4 on the secondary side of the transformer
110 is connected to the electrode 20U, and the other terminal T5 on the secondary side of the
transformer 110 is connected to the electrode 20L. One end of the bias power supply 130 is
connected to the ground GND which is the reference potential of the drive unit 100, and the
other end of the bias power supply 130 is connected to the middle terminal T3 of the
transformer 110 via the resistor R3. That is, the bias power supply 130 applies a predetermined
bias voltage (for example, 350 V) to the transformer 110. The conductive film of the vibrating
body 40U and the conductive film of the vibrating body 40L are electrically connected, and are
connected to the ground GND which is the reference potential of the drive unit 100.
[0022]
(Operation of Electrostatic Speaker 1) Next, the operation of the electrostatic speaker 1 will be
described. FIG. 5 is a view showing the operation of the electrostatic speaker 1. When an AC
acoustic signal is input to the amplifier 120, the input acoustic signal is amplified and supplied to
the primary side of the transformer 110. Then, when the voltage at the terminal on the
secondary side of transformer 110 is changed by the supplied voltage, and the potential
difference between vibrator 40U and electrode 20U is changed, the static electricity between
vibrator 40U and electrode 20U is changed. The electrostatic attraction is intensified or the
electrostatic attraction between the vibrator 40U and the electrode 20U is weakened. Also, when
the voltage at the terminal on the secondary side of the transformer 110 is changed by the
supplied voltage, and the potential difference between the vibrator 40L and the electrode 20L is
changed, the static electricity between the vibrator 40L and the electrode 20L is generated. The
electrostatic attraction is strengthened or the electrostatic attraction between the vibrator 40L
and the electrode 20L is weakened.
[0023]
First, the case where the voltage applied to the electrode 20U increases and the voltage applied
to the electrode 20L decreases will be described. When the voltage applied to the electrode 20U
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is increased, the electrostatic attractive force between the vibrator 40U and the electrode 20U is
strengthened, and the vibrator 40U is displaced in the direction of the arrow F1 as shown in FIG.
5A. Further, when the voltage applied to the electrode 20L decreases, the electrostatic attractive
force between the vibrator 40L and the electrode 20L weakens, and the vibrator 40L is displaced
in the direction of the arrow F2 as shown in FIG. 5A. . Note that the voltage applied to the
electrode 20U and the voltage applied to the electrode 20L are electrically configured to have the
same absolute value in opposite phase to each other, so the direction of the arrow F1 and the
direction of the arrow F2 In the same direction.
[0024]
Next, the case where the voltage applied to the electrode 20U decreases and the voltage applied
to the electrode 20L increases will be described. When the voltage applied to the electrode 20U
decreases, the electrostatic attractive force between the vibrating body 40U and the electrode
20U weakens, and as shown in FIG. 5B, the vibrating body 40U is displaced in the direction of the
arrow F3. In addition, when the voltage applied to the electrode 20L increases, the electrostatic
attractive force between the vibrating body 40L and the electrode 20L is strengthened, and the
vibrating body 40L is displaced in the direction of the arrow F4 as shown in FIG. . The voltage
applied to the electrode 20U and the voltage applied to the electrode 20L are electrically
configured to have the same absolute value in opposite phase to each other, so the direction of
the arrow F3 and the direction of the arrow F4 In the same direction.
[0025]
In this manner, the vibrating bodies 40U and 40L are displaced according to the acoustic signal,
and the displacement direction is sequentially changed to become vibration, and sound waves
corresponding to the vibration state (frequency, amplitude, phase) are the vibrating body 40U, It
originates from 40L. Further, in the electrostatic speaker 1, since the vibrating body 40U and the
vibrating body 40L have the same direction of displacement, the sound wave generated from the
vibrating body 40U is in phase with the sound wave generated from the vibrating body 40L, and
generated. Both sound waves are added without being canceled each other, and are emitted as
sound through the surface members 50U and 50L to the outside of the electrostatic speaker 1.
[0026]
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According to the present embodiment, since the vibrating body 40 is positioned outside the
electrode 20 in the electrostatic speaker 1, the sound wave generated from the vibrating body 40
is not electrostatically blocked by the electrode 20. It becomes possible to radiate to the outside
of 1. Therefore, in the electrostatic speaker 1, the ratio of the sound waves that can be emitted to
the outside of the electrostatic speaker 1 as compared with the conventional electrostatic
speaker in which a part of the sound waves generated from the vibrator is blocked by the
electrodes. The sound pressure of the sound wave radiated to the outside of the electrostatic
speaker 1 can be increased. Furthermore, since the vibrating body 40U and the vibrating body
40L vibrate in phase, it is possible to increase the sound pressure radiated to the outside of the
electrostatic speaker 1 compared to the case where there is one vibrating body. Further,
according to the present embodiment, the electrode 20 is formed to be higher in rigidity than the
vibrating body 40. Therefore, when the potential difference between the electrode 20 and the
vibrating body 40 changes, the vibrating body 40 is displaced in the direction attracted to the
electrode 20 or away from the electrode 20 by the action of the electrostatic attractive force.
Further, in the electrode 20, a through hole 21 penetrating from the front surface to the back
surface is formed. Therefore, in the electrode 20, the movement of the air located inside the
elastic member 30U and the air located inside the elastic member 30L according to the
displacement of the vibrating body 40, as compared with the electrode in which the through hole
is not formed It is easy to do. Further, since the electrode 20L and the electrode 20U are
disposed at predetermined intervals by sandwiching the separating member 10, the capacitance
is reduced as compared with the case where they are not disposed at predetermined intervals.
Can. Further, according to the present embodiment, only a partial region is fixed on the surface
of the vibrating body 40 in contact with the adjacent members, and therefore, when all the
regions are fixed on the surface contacting the adjacent members It is easier to displace
compared to. In addition, since the vibrating body 40 is disposed between the surface member
50 having flexibility and the elastic member 30 having elasticity, it is compared with the case
where it is disposed between members having no flexibility and elasticity. And it is easy to
displace. Further, according to the present embodiment, since the outside of the electrode 20
through which current flows is covered by the vibrating body 40 connected to the ground GND,
the possibility of an electric shock of the human body can be reduced.
[0027]
MODIFIED EXAMPLE The embodiment described above is only an example of implementation of
the present invention. The present invention can also be implemented in the mode which applied
the following modification to embodiment mentioned above. In addition, the modification shown
below may be implemented combining each suitably as needed.
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[0028]
(Modification 1) The vibrator is not limited to the one having a conductive metal deposited on
one surface of the film, and may have the conductive metal deposited on both sides of the film. .
Further, the vibrator is not limited to PET or PP, and may be a film of another synthetic resin on
which a metal having conductivity is vapor-deposited.
[0029]
(Modification 2) The elastic member and the spacing member are not limited to the non-woven
fabric, and may be members having insulation, air permeability and elasticity, for example, those
obtained by compressing heat with a batt, woven The cloth or synthetic resin may be spongy.
[0030]
(Modification 3) The shape of each member constituting the electrostatic speaker 1 is not limited
to the shape of a rectangle when viewed from the Z-axis direction, and may be another shape
such as a polygon, a circle, or an ellipse, It is also good.
[0031]
(Modification 4) A surface member should just be a member which can pass air and a sound, for
example, what heats and compressed the batting, and what made synthetic resin a spongy etc.
may be sufficient as it.
In addition, the surface member may have an image of a character, a picture, a photograph, etc.
formed on the surface thereof.
FIG. 6 is an external view of an electrostatic loudspeaker 1a according to a modification of the
present invention. In the present modification, the image 51a is printed on the surface of the
surface member 50Ua. The electrostatic loudspeaker 1a configured in this manner can emit a
sound wave associated with the image printed on the surface of the surface member 50Ua from
the surface of the surface member 50a. In addition, the electrostatic speaker 1 is not limited to
the configuration including the surface member 50, and may not include the surface member 50.
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[0032]
(Modification 5) In the embodiment described above, the dimensions in the X-axis direction and
the dimensions in the Y-axis direction of the respective members are the same in all cases, but
the dimensions may be different for each member. For example, the dimension in the X-axis
direction and the dimension in the Y-axis direction of the surface member 50 may be longer than
other members. When the dimension in the X-axis direction and the dimension in the Y-axis
direction of the surface member 50 are longer than those of the other members as described
above, the edge of the surface member 50U and the edge of the surface member 50L are
adhered to each other, and the surface member 50U and the surface member The spacer 10, the
electrode 20, the elastic member 30, and the vibrator 40 may be located in a sealed space
between 50 L and 50 L. According to this configuration, since the portion through which the
current flows is covered by the insulating surface member 50, it is possible to reduce the
possibility of the human body receiving an electric shock.
[0033]
Also, for example, the dimension in the X-axis direction and the dimension in the Y-axis direction
of the vibrating body 40 may be longer than other members. Further, when the dimensions in the
X-axis direction and the Y-axis direction of the vibrating body 40 are longer than those of other
members as described above, the edge of the vibrating body 40U and the edge of the vibrating
body 40L are adhered to each other, and the vibrating body 40U and the vibrating body The
spacer 10, the electrode 20, and the elastic member 30 may be located in a sealed space between
40L and 40L. According to this configuration, since the electrode 20 through which current
flows is covered by the vibrating body 40 connected to the ground GND, the possibility of an
electric shock of the human body can be reduced. In addition, since the vibrating body 40U and
the vibrating body 40L have the same direction of displacement, the air located in the sealed
space between the vibrating body 40U and the vibrating body 40L is not compressed or
expanded.
[0034]
(Modification 6) The electrode 20 is not limited to a punching metal, and a metal film is vapordeposited on a film of synthetic resin having insulation and flexibility such as PET or PP, and a
through hole penetrating from the front surface to the back surface 21 may be formed. That is,
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the electrode 20 may not have rigidity higher than that of the vibrating body 40. In this case, the
electrode 20 may be fixed to the spacing member 10 so as not to be displaced by the
electrostatic attraction acting between the electrode 20 and the vibrating body 40. For example,
FIG. 7 is a diagram illustrating an area to which the adhesive according to the present
modification is applied. In FIG. 7A, a region (first bonding region 21Lb) having a width of several
mm inward from the edge in the X axis direction and the edge in the Y axis direction of the
electrode 20Lb, and the X axis direction and the Y axis An adhesive is applied to a lattice-like
area (second bonding area 22Lb) in which areas having a predetermined width in the direction
have a predetermined interval. On the other hand, in the electrode 20Lb, the adhesive is not
applied to the area excluding the first adhesion area 21Lb and the second adhesion area 22Lb.
When forming the electrostatic loudspeaker, a part of the lower surface of the spacing member
10 is fixed to the first bonding area 21Lb and the second bonding area 22Lb. An adhesive may
be applied to the same region as the electrode 20Lb on the surface of the electrode 20Ub facing
the separating member 10.
[0035]
In FIG. 7B, a region (first bonding region 21Lc) having a width of several mm inward from the
edge in the X axis direction and the edge in the Y axis direction of the electrode 20Lc, and in the
X axis direction and the Y axis direction An adhesive is applied to a plurality of circular regions
(second bonding regions 22Lc) arranged at predetermined intervals. On the other hand, in the
electrode 20Lc, the adhesive is not applied to the area excluding the first adhesion area 21Lc and
the second adhesion area 22Lc. When forming the electrostatic loudspeaker, a part of the lower
surface of the spacing member 10 is fixed to the first bonding area 21Lc and the second bonding
area 22Lc. An adhesive may be applied to the same area as the electrode 20Lc on the surface of
the electrode 20Uc facing the separating member 10.
[0036]
As shown in FIG. 7, the electrode to which the adhesive is applied is fixed to the spacing member,
so that the position of the electrode and the position of the spacing member do not shift relative
to each other. That is, the electrode is not displaced by the electrostatic attractive force acting
between the electrode and the vibrator. In addition, the electrode has a degree of changing the
acoustic characteristics (amplitude, phase) of the sound wave generated from the vibrator as
compared with the case of fixing the entire area of the electrode by fixing only a partial area of
the electrode. It gets lower.
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[0037]
(Modification 7) The notch for connecting with a drive part may be provided in each member
which comprises an electrostatic type speaker. FIG. 8 is an external view of an electrostatic
loudspeaker 1d according to a modification. The electrostatic speaker 1d has the same
configuration as the electrostatic speaker 1, but the shape of each member is different. In the
present modification, only differences from the electrostatic loudspeaker 1 will be described.
[0038]
The electrostatic speaker 1d is configured by laminating the surface member 50Ld, the vibrator
40Ld, the elastic member 30Ld, the electrode 20Ld, the spacing member 10d, the electrode
20Ud, the elastic member 30Ud, the vibrator 40Ud, and the surface member 50Ud in this order. .
The surface member 50Ld and the vibrating body 40Ld have a rectangular shape as viewed from
the Z-axis direction, and no notch is provided. On the other hand, the elastic member 30Ld, the
electrode 20Ld, the spacing member 10d, the electrode 20Ud, the elastic member 30Ud, the
vibrating member 40Ud, and the surface member 50Ud are provided with notches cut out a part
of a rectangle and having a certain width in the depth direction. ing.
[0039]
The position of the notch of the electrode 20Ld in the left-right direction is the same as the
position of the notch of the elastic member 30Ld. Further, the length in the left-right direction of
the notch of the electrode 20Ld is equal to the length in the left-right direction of the notch of
the elastic member 30Ld. Further, the length in the left-right direction of the notch of the
electrode 20Ud is longer than the length in the left-right direction of the notch of the electrode
20Ld. The lateral position of the notch of the separating member 10d is the same as the notch of
the electrode 20Ud. Further, the length in the left-right direction of the notch of the separating
member 10d is equal to the length in the left-right direction of the notch of the electrode 20Ud.
Further, the length in the left-right direction of the notch of the vibrating body 40Ud is longer
than the length in the left-right direction of the notch of the electrode 20Ud. The position in the
left-right direction of the notch of the elastic member 30Ud is the same as the position of the
notch of the vibrating body 40Ud. Further, the length in the left-right direction of the notch of
the elastic member 30Ud is equal to the length in the left-right direction of the notch of the
vibrating body 40Ud. Further, the length in the left-right direction of the notch of the surface
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member 50Ud is longer than the length in the left-right direction of the notch of the vibrating
body 40Ud.
[0040]
FIG. 9 is an enlarged view of a part of the top surface of the electrostatic speaker 1d. The notch
of the electrode 20Ld and the notch of the elastic member 30Ld are shorter in length in the leftright direction than the notch of the electrode 20Ud and the separating member 10d, and viewed
from above, within the region of the notch of the electrode 20Ud and the separating member 10d
positioned. Further, the notch of the electrode 20Ud and the notch of the separating member
10d have a shorter length in the lateral direction than the notch of the vibrating body 40Ud and
the elastic member 30Ud, and the notch of the vibrating body 40Ud and the elastic member
30Ud when viewed from above Located in the area of Further, the notch of the vibrating body
40Ud and the notch of the elastic member 30Ud are shorter in length in the left-right direction
than the notch of the surface member 50Ud, and when viewed from above, are located within the
notch region of the surface member 50Ud There is.
[0041]
The electrostatic speaker 1 d is connected to the drive unit 100 by the clip 200. FIG. 10A is a
front view of the clip 200, and FIG. 10B is a side view of the clip 200. As shown in FIG. The clip
200 has rectangular plate-like electrodes 201 d to 204 d and a spring 210. The clip 200 also has
a plate-like plastic plate portion 220A to which the electrodes 201d to 204d are fixed, and a
plate-like plastic plate portion 220B facing the plate portion 220A. The electrode 201 d is
connected to the ground GND of the drive unit 100 via a conductor (not shown). The electrode
202d is connected to the terminal T5 on the output side of the transformer 110 via a wire (not
shown). The electrode 203 d is connected to the terminal T 4 on the output side of the
transformer 110 via a conductor (not shown). The electrode 204 d is connected to the ground
GND of the drive unit 100 via a conductor (not shown).
[0042]
FIG. 11 is a view showing a state in which the electrostatic speaker 1 d is sandwiched by the clip
200. By sandwiching the notched portion of the electrostatic speaker 1d with the clip 200, the
electrode 201d and the vibrating body 40Ld, the electrode 202d and the electrode 20Ld, the
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electrode 203 and the electrode 20Ud, and the electrode 204d and the vibrating body 40Ud
respectively contact. The acoustic signal output from the terminal T5 is supplied to the electrode
20Ld via the electrode 202d, and the acoustic signal output from the terminal T4 is supplied to
the electrode 20Ud via the electrode 203d. The vibrating body 40Ud is connected to the ground
GND via the electrode 204d, and the vibrating body 40Ld is connected to the ground GND via the
electrode 201d.
[0043]
In this modification, only by sandwiching the electrostatic speaker 1d with the clip 200, the
electrostatic speaker 1d and the drive unit 100 can be connected, and a voltage corresponding to
the acoustic signal can be applied to each electrode. Further, when the clip 200 is removed from
the electrostatic speaker 1 d, the electrostatic speaker 1 d and the drive unit 100 can be
separated, so that the electrostatic speaker 1 d can be easily carried.
[0044]
(Modification 8) The electrostatic speaker is connected to the drive unit by sandwiching the
electrostatic speaker with the clip having the electrode, but the configuration for connecting the
electrostatic speaker and the drive unit is limited to this is not. FIG. 12 is an external view of an
electrostatic loudspeaker 1e according to a modification. The electrostatic speaker 1e is
configured by laminating the surface member 50Le, the vibrator 40Le, the elastic member 30Le,
the electrode 20Le, the spacing member 10e, the electrode 20Ue, the elastic member 30Ue, the
vibrator 40Ue, and the surface member 50Ue in this order. . The electrode 20Ue is a plate-like
member having conductivity, and has higher rigidity (large Young's modulus) than the vibrator
40e (lower Young's modulus) and lower rigidity than electrodes 201e to 204e described later.
Further, the electrode 20 e is formed with a plurality of through holes penetrating from the front
surface to the back surface. The vibrating body 40Le and the vibrating body 40Ue are provided
with one notch which is partially recessed and recessed with a certain width in the depth
direction, and two notches are constant in the electrode 20Ue and the electrode 20Le. It is
provided at intervals. The surface member 50Le, the elastic member 30Le, the spacing member
10e, the elastic member 30Ue, and the surface member 50Ue do not have conductivity and are
not connected to the drive unit 100, so a notch is provided. Even if it does not have to be
provided.
[0045]
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The electrostatic speaker 1 e is connected to the drive unit 100 by the clip 200. As shown in FIG.
12, the clip 200 is provided with electrodes 201 e to 204 e having a needle shape. The electrode
201e is connected to the ground GND of the drive unit 100 via a conductor (not shown). The
electrode 202e is connected to the terminal T5 on the output side of the transformer 110 via a
wire (not shown). The electrode 203 e is connected to the terminal T 4 on the output side of the
transformer 110 via a wire (not shown). The electrode 204 e is connected to the ground GND of
the drive unit 100 via a conductor (not shown).
[0046]
In the electrostatic loudspeaker 1e, the positions of the notches provided in the vibrator 40Le,
the electrode 20Le, the electrode 20Ue, and the vibrator 40Ue in the left-right direction are
different from each other. More specifically, although the vibrating body 40Le is present at the
point P1, the electrode 20Le, the electrode 20Ue and the vibrating body 40Ue are not present
due to the notch. In addition, although the electrode 20Le is present at the point P2, the vibration
body 40Le, the electrode 20Ue and the vibration body 40Ue are not present due to the notch. In
addition, although there is an electrode 20Ue at the point P3, the notch does not cause the
vibrating body 40Le, the electrode 20Le and the vibrating body 40Ue. Although the vibrating
body 40Ue is present at the point P4, the vibrating body 40Le, the electrode 20Le, and the
electrode 20Ue are not present because of the notch. By sandwiching the cut portion of the
electrostatic speaker 1e configured in this way with the clip 200, the electrode 201e is pierced at
the point P1 shown in FIG. 12, the electrode 202e is pierced at the point P2, and the electrode
203e is joined at the point P3. The electrode 204e is pierced at the point P4.
[0047]
In this case, the electrode 201e contacts only the vibrating body 40Le among the conductive
members, and does not contact other conductive members. For this reason, only the vibrating
body 40Le is connected to the ground GND via the electrode 201e. Further, the electrode 202e
contacts only the electrode 20Le among the conductive members, and does not contact other
conductive members. Therefore, only the electrode 20Le is supplied with the acoustic signal
output from the terminal T5 through the electrode 202e. In addition, the electrode 203 e is in
contact with only the electrode 20 U e among the members having conductivity, and does not
contact other members having conductivity. Therefore, only the electrode 20Ue is applied with
the bias voltage supplied from the bias power supply 132 via the electrode 203e. In addition, the
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electrode 204e is in contact with only the vibrating body 40Ue among the members having
conductivity, and does not contact other members having conductivity. Therefore, only the
vibrating body 40Ue is supplied with the acoustic signal output from the terminal T4 via the
electrode 204e. As described above, also in the present modification, the acoustic signal from the
drive unit 100 can be supplied to the electrostatic speaker 1 e only by sandwiching the
electrostatic speaker 1 e by the clip 200.
[0048]
(Modification 9) In the embodiment and the modification described above, an example has been
described in which the electrostatic electroacoustic transducer is applied to an electrostatic
speaker that converts an acoustic signal (electric signal) into sound (sound). Electrostatic
transducers of the electrostatic type may be applied to electrostatic microphones that convert
sound (sounds) into acoustic signals (electrical signals). FIG. 13 is a diagram showing the
electrical configuration of the electrostatic microphone 1M according to this modification. In the
configuration shown in FIG. 13, the electrostatic microphone 1 M has the same
configuration as the electrostatic speaker 1 of FIG. 4 described above. The driving unit 100M is
connected to the electrostatic microphone 1M. The drive unit 100M has the same configuration
as the drive unit 100 of FIG. 4 described above, but the transformation ratio of the transformer
110 and the resistance values of the resistors R1 to R3 may be appropriately adjusted, and are
input to and output from the amplifier 120. The direction of the acoustic signal is different from
that in FIG.
[0049]
When a sound is generated outside, the vibrating bodies 40U and 40L vibrate as shown in FIGS.
5 (a) and 5 (b) by the sound, and between the vibrating body and the electrodes according to the
vibration. As the distance changes, a change occurs in the capacitance between the vibrator and
the electrode. Since the electrodes 20U and 20L are connected to the bias power supply 130 via
the resistor R3, the charge remains constant even if the capacitance changes.
[0050]
Here, the operation of the electrostatic microphone 1M when the vibrators 40U and 40L vibrate
as shown in FIG. 5A will be described. First, as the distance between the vibrating body 40U and
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the electrode 20U decreases, the capacitance between the vibrating body 40U and the electrode
20U increases. Here, since the vibrating body 40U is connected to the ground GND, the potential
of the electrode 20U changes so that the potential difference between the vibrating body 40U
and the electrode 20U decreases. Similarly, by increasing the distance between the vibrator 40L
and the electrode 20L, the capacitance between the vibrator 40L and the electrode 20L
decreases. Here, since the vibrating body 40L is connected to the ground GND, the potential of
the electrode 20L changes so that the potential difference between the vibrating body 40L and
the electrode 20L becomes large.
[0051]
Next, the operation of the electrostatic microphone 1M when the vibrators 40U and 40L vibrate
as shown in FIG. 5B will be described. First, by increasing the distance between the vibrating
body 40U and the electrode 20U, the capacitance between the vibrating body 40U and the
electrode 20U decreases. Here, since the vibrating body 40U is connected to the ground GND, the
potential of the electrode 20U changes so that the potential difference between the vibrating
body 40U and the electrode 20U becomes large. Similarly, as the distance between the vibrating
body 40L and the electrode 20L is shortened, the capacitance between the vibrating body 40L
and the electrode 20L is increased. Here, since the vibrating body 40L is connected to the ground
GND, the potential of the electrode 20L changes so that the potential difference between the
vibrating body 40L and the electrode 20L decreases.
[0052]
As described above, as a result of the operation of the electrostatic microphone 1M, a voltage
output in which changes in the potentials of the electrodes 20U and 20L are proportional to the
displacement of the vibration, that is, a transformer via the terminals T4 and T5 as acoustic
signals. It will be supplied to 110. Then, the transformer 110 transforms this acoustic signal and
inputs it to the amplifier 120, and the amplifier 120 amplifies this acoustic signal and outputs it
to a speaker, a computer or the like (not shown).
[0053]
As described above, in the electrostatic microphone 1 M, the externally generated sound
directly vibrates the vibrating bodies 40 U and 40 L without being blocked by the
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electrodes 20 U and 20 L. Therefore, in the electrostatic microphone 1M, the
vibrating bodies 40U and 40L are more easily vibrated as compared with the configuration in
which the electrodes are disposed outside the vibrating body, so that the externally generated
sound is converted into an acoustic signal. It will be easier.
[0054]
By the way, although the electrostatic microphone 1 M supplies the acoustic signal to the
transformer 110 of the drive unit 100 M in the ninth modification, the acoustic signal may
be supplied to other than the transformer 110. For example, when the impedance of the
transformer 110 is low, the load capacitance of the electrostatic microphone 1M may reduce the
frequency characteristics at low frequencies. In such a case, the electrostatic microphone 1 
M may suppress the deterioration of the frequency characteristic at a low frequency by
supplying an acoustic signal to the amplifier 120 having a higher impedance than the
transformer 110.
[0055]
1, 1a, 1d, 1e: electrostatic speaker (electroacoustic transducer of electrostatic type), 10:
separating member, 20: electrode, 21: through hole, 30: elastic member, 40: vibrator, 50: surface
Members, 51a: image, 100: driving unit, 110: transformer, 120: amplifier, 130: bias power
supply, 1M: electrostatic microphone (electrostatic electroacoustic transducer of electrostatic
type), 100M: driving unit
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