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JP2006148612

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2006148612
PROBLEM TO BE SOLVED: To be able to improve the moisture resistance performance to
improve the handleability. SOLUTION: A vibrating membrane 11, a pair of fixed electrode layers
12 and 12 laminated at positions sandwiching the vibrating membrane 11 from both sides, and
the fixed electrode layers 12 and 12 provided on the opposite side to the vibrating membrane 11
The electrostatic speaker 10 is configured to include the pair of porous layers 13 and 13. A
water repellent layer 20 is provided on the outside of the porous layer 13. The water repellent
layer 20 prevents water from infiltrating toward the vibrating membrane 11 and suppresses the
water from reaching the fixed electrode layer 12. [Selected figure] Figure 1
Sound equipment
[0001]
The present invention relates to an acoustic device, and more particularly, to an acoustic device
capable of improving moisture resistance performance.
[0002]
Conventionally, an acoustic device such as an electrostatic speaker is known. This acoustic device
includes a sheet-like vibrating film, and a pair of conductive fixed electrode layers disposed on
both sides of the vibrating film. And a porous layer which is laminated on the outside of each
fixed electrode layer to maintain the fixed shape of the fixed electrode layer.
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The fixed electrode layer and the porous layer are made of an air-permeable material such as a
non-woven fabric, and transmit the reproduced sound due to the vibration of the vibrating
membrane (see Patent Document 1). Japanese Patent Application Publication No. 2002-513263
[0003]
However, in such an acoustic device, when it is left at a location where the humidity is relatively
high, there is a disadvantage that the capacitance decreases and the reproduction sound pressure
decreases. This is because the fiber bond of the non-woven fabric is broken by containing water,
and it is difficult to conduct electricity to the fixed electrode layer to reduce the electrode
effective area, or the fixed electrode layer is exposed to water and oxidized to function as an
electrode. It is guessed to be insufficient. As a result, the humidity is controlled to be kept
relatively low, and a large burden is imposed on handling, and the sound pressure drop can not
be avoided in the place where the humidity control can not be performed.
[0004]
[Object of the Invention] The present invention has been made in view of such inconveniences,
and it is an object of the present invention to provide an acoustic device capable of improving the
moisture resistance performance to improve the handling property. is there.
[0005]
In order to achieve the above object, according to the present invention, there is provided an
acoustic device comprising: a vibrating membrane; and a conductive fixed electrode layer
laminated so as to include an air gap between the vibrating membrane; A configuration in which
a water repellent layer is provided on the side opposite to the membrane is adopted.
[0006]
Further, according to the present invention, there is provided a pair of conductive electrodes
having conductivity and being disposed at a position sandwiching the vibrating membrane from
both sides with the vibrating membrane and including a gap between the vibrating membrane
and the vibrating membrane. In an acoustic device including a layer and a porous layer
respectively provided on the side opposite to the vibrating film in each fixed electrode layer, a
configuration in which a water repellent layer is provided on the porous layer side from the fixed
electrode layer is also adopted. be able to.
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[0007]
In the present invention, a configuration is adopted in which the water repellent layer is provided
on at least one surface of the porous layer and / or in the middle in the thickness direction.
[0008]
Further, the water repellent layer may be formed by applying a predetermined water repellent
material.
[0009]
Further, it is preferable to adopt a configuration in which a water capture layer is provided
outside the water repellent layer, and the water capture layer absorbs water vapor and converts
it into water molecules.
[0010]
According to the present invention, even when the humidity is relatively high, the water repellent
layer can suppress water and moisture in the air from reaching the fixed electrode layer, and the
capacitance can be stably maintained to reproduce sound. It is possible to prevent the pressure
from decreasing.
As a result, it is possible to improve the handling and ease the restriction of the installation
space, and to spread it in various usage scenes such as stores and transportation facilities.
[0011]
Moreover, when a water repellent layer is provided in the thickness direction middle part of the
porous layer, the water repellent layer can be covered from the outside to prevent aging and the
like.
On the other hand, when provided on the outer surface side of the porous layer, it is possible to
easily form a water repellent layer on a generally circulating acoustic device, and to protect the
entire porous layer from moisture etc. to improve the moisture resistance performance. Become.
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[0012]
Furthermore, when forming a water repellent layer by application of a water repellent material,
for example, by using a spray etc., the water repellent effect can be obtained easily and quickly.
[0013]
In addition, when the water capture layer is provided outside the water repellent layer, the water
vapor absorbed by the water capture layer becomes water molecules and the water vapor does
not easily reach the water repellent layer, so that the water permeates through the water
repellent layer. It can be better avoided.
[0014]
In the present specification and claims, unless specified otherwise, “inner” is used as the side
closer to the vibrating membrane, while “outer” is used as the opposite side.
[0015]
Hereinafter, preferred embodiments of the present invention are described with reference to the
drawings.
[0016]
FIG. 1 shows a cross-sectional view of the electrostatic speaker according to the present
embodiment, and FIG. 2 shows an exploded view thereof.
In these figures, the electrostatic speaker 10 as an acoustic device includes a vibrating
membrane 11, a pair of fixed pole layers 12 and 12 stacked at positions sandwiching the
vibrating membrane 11 from each other, and each fixed pole layer 12, The vibrating membrane
11 in FIG. 12 and a pair of porous layers 13 and 13 provided on the opposite side are
configured.
[0017]
The vibrating film 11 is composed of a conductive metal film 11A such as aluminum, and a pair
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of chargeable insulating films 11B and 11B stacked on both sides of the metal film 11A.
A control electrode A for inputting an electrical signal corresponding to the sound generated
from the electrostatic speaker 10 is connected to the metal film 11A.
The insulating film 11B is configured using, for example, polypropylene, polymethylpentene or
cyclic olefin copolymer in addition to PET resin.
[0018]
The fixed electrode layers 12 and 12 and the porous layers 13 and 13 are vertically symmetrical
in FIG. 1 with the vibrating membrane 11 interposed therebetween.
Therefore, in the following, the same reference numerals are given to the lower layers 12 and 13
in the lower side of the figure, and the description thereof will be omitted as the upper fixed
electrode layer 12 and the porous layer 13 in the figure are described.
[0019]
The fixed electrode layer 12 is formed of a non-woven fabric having conductivity, and
specifically, is formed by impregnating a non-woven fabric with a metal material such as
aluminum or sputtering or vapor depositing a metal material on the inner surface.
The non-woven fabric can be made of cellulose, glass fiber, mineral fiber, metal fiber, or can be
made by sintering a plastic or metal powder.
[0020]
The fixed electrode layer 12 is formed in a shape in which a plurality of irregularities are
continuous in cross section.
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In other words, while the fixed electrode layer 12 is provided at predetermined intervals along
the left-right direction, the fixed electrode layer 12 is located between the plurality of recessed
portions 12A formed to be recessed upward and the adjacent recessed portions 12A. The
adhesive portion 12B is adhered to the vibrating film 11 through the adhesive layer 16 such as a
system.
The recessed portion 12A forms an air gap 17 between itself and the vibrating membrane 11, so
that the vibrating membrane 11 can vibrate in the air gap 17.
A fixed electrode E for applying a predetermined bias voltage to the fixed electrode layer 12 is
connected to the fixed electrode layer 12.
[0021]
The porous layer 13 is laminated on the fixed electrode layer 12 via the adhesive layer 18 such
as polyamide, and the intermediate layer 13A, the adhesive layer 13B and the outer side are
sequentially laminated from the adhesive layer 18 outward. It consists of layer 13C. The
intermediate layer 13A is compression molded so that the region corresponding to the adherend
12B protrudes. The middle layer 13A and the outer layer 13C are made of a non-woven fabric,
and impart fixed shape to the fixed electrode layer 12 while transmitting sound generated by the
vibration of the vibrating membrane 11.
[0022]
A water repellent layer 20 is provided on the outer surface of the outer layer 13C of the porous
layer 13. The water repellent layer 20 is made of a material that transmits the sound from the
vibrating film 11 while preventing water from penetrating toward the inside (the vibrating film
11 side). As the water repellent layer 20, it can be exemplified to apply a water repellent material
through a spray or the like. Examples of the water repellent material include polymer materials
such as fluorine resin and silicon resin. Further, as the water repellent layer 20, a non-woven
fabric in which the water repellent material is bonded to the surface of each single fiber can be
exemplified. The single fiber is one in which a fluorine resin is bonded to the surface of each fiber
in a raised state, and each fiber is a natural fiber such as wood fiber, cotton, wool or hemp,
chemical fiber, semi-synthetic fiber Or these may be combined suitably. As the fluorine resin to
04-05-2019
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be used, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer
(PFA), tetrafluoroethylene-hexafluoropropylene copolymer (PFEP), ethylene-tetrafluoroethylene,
and the like Copolymers (PETFE), ethylene-chlorotrifluoroethylene copolymer (PECTFE),
polychlorotrifluoroethylene (PCTFE) and the like can be mentioned. Furthermore, the water
repellent layer 20 may be formed of a fluorine resin in the form of a film having a porous
structure provided with a large number of holes that transmit air.
[0023]
In the above configuration, the vibrating film 11 vibrates in the air gap portion 17 by applying a
predetermined bias voltage to the fixed electrode E and applying an electric signal to the control
electrode A via a predetermined control device (not shown). Do. By this vibration, a sound is
generated, and the sound is transmitted through the fixed electrode layer 12, the porous layer 13
and the water repellent layer 20 and emitted.
[0024]
Next, in order to confirm the effects according to the present invention, the following examples
are shown together with comparative examples.
[0025]
Example In the example, using the electrostatic speaker 10 shown in FIG. 1 set to the conditions
of Table 1, the outer surface side of the porous layer 13 is coated with a water repellent material
containing perfluoroalkyl acrylate. The water repellent layer 20 was formed.
The electrostatic speaker 10 was left for 24 hours under the conditions of 40 ° C. and 90%
humidity, and then left for 24 hours under normal temperature for humidity resistance.
[0026]
[0027]
Comparative Example For the example, an electrostatic speaker without the water repellent layer
20 was used, and the other conditions were the same.
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[0028]
The electrostatic capacitance was measured with respect to each electrostatic speaker of an
Example and a comparative example.
The timing of measuring the capacitance was in the unused state and after being left moisture
resistant.
The results are shown in Table 2 and FIG. Moreover, the acoustic characteristic was measured in
the anechoic chamber with respect to each electrostatic speaker of an Example and a
comparative example. The timing of measuring the acoustic characteristics was in an unused
state and after being left moisture resistant. The results are shown in FIG. 4 and FIG.
[0029]
[0030]
As is clear from these charts, when comparing the unused state and after leaving moisture-proof,
in the example, while both the capacitance and the reproduced sound pressure hardly change, in
the comparative example, the capacitance and Both playback sound pressure is decreasing.
Thus, it is understood that, compared to the comparative example, the structure of the example
can avoid the reduction of the capacitance and the reproduction sound pressure even under high
sound and humidity conditions, and the moisture resistance performance is improved. Note that
conditions other than the above-described embodiment, for example, even if the material of the
metal film 11A is made of a metal other than aluminum or the porous layer 13 is made of only
one layer of the intermediate layer 13A, It is expected that equivalent results will be obtained.
[0031]
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Although the best configuration, method and the like for practicing the present invention are
disclosed in the above description, the present invention is not limited thereto. That is, although
the present invention has been particularly illustrated and described with respect to particular
embodiments, it is to be understood that the present invention may be configured relative to the
above-described embodiments without departing from the scope of the inventive concept and
object. Those skilled in the art can make various modifications in position, orientation, and other
detailed configurations. Therefore, the descriptions with the above-described disclosure of the
shapes and the like are exemplarily described in order to facilitate the understanding of the
present invention, and are not intended to limit the present invention. The description in the
name of the member which removed the one part or all limitation is contained in this invention.
[0032]
The electrostatic speaker 10 can reproduce sound by the diaphragm 11, and various design
changes can be made as long as it can exhibit the moisture resistance performance as described
above. For example, with respect to the structure of the embodiment, the porous layer 13 may be
omitted and the water repellent layer 20 may be provided on the outer side of the fixed electrode
layer 12 or any one fixed electrode layer 12 may be omitted. Further, the water repellent layer
20 may be provided between each of the layers 13A to 13C forming the porous layer 13 or
between the porous layer 13 and the fixed electrode layer 12.
[0033]
In addition, as shown in FIG. 6, a configuration may be considered in which a water trapping
layer 22 is further provided on the outside of the water repellent layer 20. At this time, the water
capture layer 22 is made of a material such as a porous material such as activated carbon or
silica gel capable of absorbing water vapor and converting the water vapor into water molecules
inside. According to this, not only it becomes difficult for water vapor to directly touch the water
repellent layer 20, but the collected water is dried with time and the water repellent layer 20 is
substantially restored to the initial state. It becomes possible to obtain the water repellent effect
better.
[0034]
Furthermore, although the acoustic device is the electrostatic speaker 10 in the embodiment, it
may be an electrostatic microphone that measures a signal corresponding to the vibration of the
diaphragm 11 through the control electrode A.
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[0035]
BRIEF DESCRIPTION OF THE DRAWINGS The schematic sectional drawing of the electrostatic
speaker which concerns on embodiment.
FIG. 2 is an exploded view of FIG. (A) is a graph which shows the measurement result of the
electrostatic capacitance of an Example, (B) is a graph which shows the measurement result of
the electrostatic capacitance of a comparative example. The line which shows the measurement
result of the acoustic characteristic by an example. FIG. 7 is a diagram showing measurement
results of acoustic characteristics according to a comparative example. Sectional drawing similar
to FIG. 1 of the electrostatic speaker which concerns on a modification.
Explanation of sign
[0036]
DESCRIPTION OF SYMBOLS 10 ... Electrostatic speaker (sound device), 11 ... Vibrating film, 12 ...
Fixed-electrode layer, 13 ... Porous layer, 17 ... Void part, 20 ... Water-repellent layer, 22 ・ ・ ・
Water catchment
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