JP2006287830

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DESCRIPTION JP2006287830
PROBLEM TO BE SOLVED: To provide an electro-acoustic transducer that can be easily and
inexpensively manufactured with a small number of man-hours by preventing overflow and short
circuit when filling a photocurable resin in a mold mold clearance and also preventing air bubble
entrapment. Provided are a method of manufacturing a diaphragm and a diaphragm for an
electroacoustic transducer manufactured thereby. SOLUTION: The upper and lower molds are
clamped, and a clearance of the mold is filled with a photocurable resin from the outside through
a gate. This prevents the overflow and short of the photocurable resin, and the inclusion of air
bubbles when the resin is filled. At least one of the upper and lower molds is made of a material
that transmits light, and is irradiated with ultraviolet light and / or visible light from the outside
to cure the photocurable resin, thereby producing a diaphragm. [Selected figure] Figure 2
Method of manufacturing diaphragm for electro-acoustic transducer and diaphragm for electroacoustic transducer
[0001]
The present invention relates to a method of manufacturing a diaphragm for an electroacoustic
transducer such as a speaker or a microphone, which is a kind of audio equipment, and a
diaphragm for an electroacoustic transducer.
[0002]
Conventionally, as shown in, for example, Japanese Patent Application Laid-Open No. 2001204904, diaphragms for microspeakers and diaphragms for dome speakers are mainly films,
woven fabrics coated with rubber or the like, plane-shaped materials such as elastomers, etc.
alone or These are often used in combination.
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[0003]
Examples of film materials include PET: polyethylene terephthalate, PEI: polyether imide, PC:
polycarbonate, PEN: polyethylene naphthalate, PI: polyimide and the like.
[0004]
Moreover, as an example of the woven fabric which coated rubber etc., rubber coats, such as SBR
and NBR, exist in base materials, such as cellulose fiber woven fabric and chemical fiber woven
fabrics, such as polyester.
[0005]
Examples of the elastomer include elastomers such as olefin-based, urethane-based and EPDMbased.
[0006]
Further, as a molding method, there are vacuum molding, pressure molding, heating and
pressure molding using a molding die (hereinafter referred to as upper and lower dies) in which
an upper die and a lower die are combined, and an injection molding method.
Patent Document 1: Japanese Patent Application Publication No. 2001-204094
[0007]
In vacuum forming, pressure forming, heating and pressure forming using upper and lower
molds, etc., it is necessary to raise the mold temperature to near the melting point of the material,
and a great deal of energy is required for heating.
In addition, since the mold needs to be cooled and taken out, it takes a long time for the molding
cycle.
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[0008]
In the injection molding method, it is difficult to obtain a thin diaphragm because the molten
resin is cooled immediately after the molten resin comes into contact with the mold having a
temperature difference, and it is difficult to obtain a thin diaphragm. In the process of, the
equipment also becomes expensive.
In addition, the heating energy is enormous since the thermoplastic material is heated to near the
melting point.
[0009]
The material to be used for forming is a flat material which is substantially larger than the part
size in vacuum forming, pressure forming, heating and pressure forming using upper and lower
molds, etc., and parts are cut out and used, resulting in generation of waste. It is not desirable.
It also leads to rising prices of parts.
[0010]
Since the above-mentioned constituent materials of vacuum forming, pressure forming, and heat
forming by upper and lower molds are generally materials of uniform thickness, after forming,
they have substantially the same thickness in each part.
The material of uniform thickness can not change the thickness (i.e. stiffness) of each part of the
diaphragm. A method has been proposed in which the thickness is changed by changing the
mold clearance or performing processing such as drawing at the time of molding as shown in
Japanese Patent No. 3384098, but internal stress distortion after molding is large, In addition,
there is a disadvantage that the molding die and the like become complicated.
[0011]
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Although an edge, a gasket or the like may be joined to the formed diaphragm by an adhesive,
the application amount of the adhesive may vary, causing variations in adhesive strength and the
like, resulting in unstable characteristics. In the case of a material having poor adhesion, it is
necessary to carry out a secondary treatment such as a primer. As described above, in the fixing
method using an adhesive, there is a problem in reliability, and an additional processing time is
required, leading to a price increase.
[0012]
Planar materials such as films have a limited thickness which is manufactured industrially, and
obtaining materials of other thicknesses is usually economically difficult.
[0013]
In addition, planar materials such as films are limited in physical property values of materials
manufactured industrially, and obtaining materials containing reinforcing materials such as
fillers is usually technical and economic. Difficult.
[0014]
The present invention has been proposed in view of the above, and the object of the present
invention is to prevent overflow and short-circuiting when filling the photocurable resin in the
clearance of the mold and to prevent the inclusion of air bubbles, It is an object of the present
invention to provide a method of manufacturing a diaphragm for an electroacoustic transducer
that can be manufactured easily and inexpensively with a small number of man-hours, and the
diaphragm for an electroacoustic transducer manufactured thereby.
[0015]
According to the first aspect of the present invention, at least one of a pair of upper and lower
molds is formed of a material that transmits ultraviolet light and / or visible light, and the mold is
closed. The internal clearance is filled with an ultraviolet and / or visible light curing resin
through the gate formed in the mold from the outside, and the UV and / or visible light is
irradiated from the outside of the mold to cure the resin and the diaphragm Molding.
According to the invention as set forth in claim 2, in the method of manufacturing the diaphragm
for electro-acoustic transducer according to claim 1, the gate is formed on one side of the mold
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and an air vent is formed on the opposite side. It is characterized by
According to the third aspect of the present invention, at least one of a pair of upper and lower
molds is formed of a material that transmits ultraviolet light and / or visible light, and a
diaphragm body is formed on the lower mold. The mold is closed by closing the mold, and the
outer periphery of the diaphragm body is filled with an ultraviolet and / or visible light curing
resin from the outside through the gate formed on the mold, from the outside of the mold It is
characterized in that ultraviolet rays and / or visible rays are irradiated to cure the resin and an
edge is integrally formed on the outer periphery of the diaphragm body.
According to the invention of claim 4, at least one of a pair of upper and lower molds is formed
of a material which transmits ultraviolet light and / or visible light, and any one of the upper
mold and the lower mold is used. A gasket is set on the outer periphery of the mold, the mold is
closed, the resin cured by ultraviolet light and / or visible light is filled from the outside through
the gate formed on the mold, and ultraviolet light is applied from the outside of the mold And /
or irradiating visible light to cure the resin to integrally form the gasket, the diaphragm body and
the edge. According to invention of Claim 5, it produced by the method in any one of the said
Claims 1-4, It is characterized by the above-mentioned.
[0016]
According to the first and second aspects of the invention, ultraviolet light and / or visible light
can be applied to the photocurable resin filled in the mold closed as compared with vacuum
molding, pressure forming, heating and pressure molding using upper and lower molds, etc. The
diaphragm can be easily manufactured because it is sufficient to irradiate only. In this case, since
the photocurable resin is filled from the gate on the side surface in the mold which has been
clamped in advance and the air vent holes are provided in the reverse direction of the gate, the
photocurable resin overflows in the clearance in the mold. It is possible to prevent short
circuiting and air bubbles during resin filling, etc., and a diaphragm with good performance can
be obtained.
[0017]
That is, when filling the photocurable resin, there is a method of dropping the photocurable resin
in the same amount as the clearance volume from above to the clearance of the lower mold, and
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closing the upper mold. It is difficult to drip the photocurable resin of the above-mentioned, and
overflow or short circuit of the photocurable resin occurs. In addition, in such a filling method,
the inclusion of air bubbles occurs, which causes a problem in the performance of the speaker.
On the other hand, in the present invention, since the photocurable resin is filled from the gate
on the side surface of the mold which has been clamped in advance, such a problem does not
occur.
[0018]
According to the third aspect of the present invention, since the diaphragm body having the
desired physical properties can be used, the desired characteristics can be obtained, and the edge
can be easily integrated using the optical technology according to the first and second aspects.
There is an effect that can be
[0019]
According to the fourth aspect of the present invention, since manufacture is easy, it is
inexpensive and there is no embrace of air bubbles, so that it is possible to obtain a diaphragm
having no problem in the performance of the speaker.
[0020]
Ultraviolet light is generally an electromagnetic wave having a wavelength of 10 to 400 nm, and
400 nm to 800 nm is called visible light.
A general UV curable resin that cures when irradiated with UV light includes a base resin
(monomer, oligomer), a reactive diluent, a photopolymerization initiator, an additive, etc. It is in a
slick state.
There are a radical polymerization type and a cation polymerization type when classified from
the polymerization form.
[0021]
The former radical polymerization type includes epoxy acrylate, urethane acrylate, polyester
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acrylate, silicone acrylate and the like as a base resin, and photopolymerization initiators include
benzoin ethers, benzophenone amines, acetophenones, thioxanthones and the like. The
photopolymerization initiator reacts with specific wavelengths of ultraviolet light and visible light
to generate free radicals, causes polymerization of the base resin, and cures in a short time of
several seconds to several tens of seconds.
[0022]
The latter cationic polymerization type includes alicyclic epoxy resin, glysyl ether epoxy resin,
epoxy acrylate, vinyl ether as a base resin, and as a photopolymerization initiator, Lewis acid
dianium salt, Lewis acid sulfonium salt, Lewis acid iodonium There is salt etc. The
photopolymerization initiator reacts at a specific wavelength of ultraviolet light and visible light
to generate a cation, causes polymerization of the base resin, and cures in a short time of several
seconds to several tens of seconds.
[0023]
There are halogen lamp, metal halide lamp, high pressure mercury lamp, super high pressure
mercury lamp, xenon lamp, xenon excimer lamp, xenon flash lamp (pulsed light emission), light
emitting diode etc. as a radiation light source for efficiently generating ultraviolet light and / or
visible light. Radiation wavelength and energy distribution are different. These light sources are
selected according to the reaction wavelength of the photopolymerization initiator and the like.
In addition, natural light (sunlight) can also be a reaction initiator depending on the type of
photopolymerization initiator.
[0024]
These light sources can be directly irradiated, condensed irradiation by a reflecting mirror or the
like, condensed irradiation by a fiber or the like. Thermal energy is also reduced by using a heat
ray cut filter, a cold mirror or the like.
[0025]
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Examples of the material of the type that transmits ultraviolet light and / or visible light include
quartz glass, soda glass, acrylic resin, polycarbonate resin and the like. Table 1 shows the
transmittances of these ultraviolet light and / or visible light.
[0026]
[0027]
The method for producing a diaphragm for an electroacoustic transducer according to the
present invention comprises a urethane acrylate resin as a main component, and benzoin ether
and benzophenone amines as a photopolymerization initiator and has a viscosity of 20,000 [mPa
· s] at 20 ° C. The photocurable resin that cures with ultraviolet light and / or visible light is
clamped with the upper and lower molds preferably made of acrylic resin having a diaphragmshaped clearance, and the mold is filled with the photocurable resin through the gate. After that,
a light beam from an irradiation device using an extra-high pressure mercury lamp as a light
source was irradiated from above the mold for 5 seconds.
At this time, the illuminance of the light beam after passing through the mold was 10 mW / cm
<2> at a wavelength of 365 nm, and 120 mW / cm <2> at a wavelength of 405 nm. The upper
and lower molds were later opened and taken out to obtain a diaphragm.
[0028]
Embodiment 1 FIGS. 1 to 6 show a first embodiment of the present invention.
[0029]
In this first embodiment, first, as shown in FIG. 1, a molding die comprising a lower die 1
corresponding to the diaphragm shape and having an uneven surface and an upper die 2
corresponding thereto is provided. There is.
At least one of the lower mold 1 and the upper mold 2 is made of a material that transmits
ultraviolet light and / or visible light, but both may be made of a transparent material.
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[0030]
FIG. 2 shows a state in which the lower mold 1 and the upper mold 2 are clamped. A clearance 3
for filling the photocurable resin is formed in the clamped mold. This clearance preferably has a
diaphragm body 3a, an edge portion 3b on the outer periphery thereof, and a gasket portion 3c
on the outer periphery thereof, and the diaphragm is formed.
[0031]
Further, a gate 4 for resin filling is formed on one side surface of the mold, and an air vent hole is
formed on the other side surface on the opposite side. The gate 4 is formed in one place
substantially at the center of the joint between the clamped upper and lower dies 2 and 1. Note
that a plurality of gates 4 may be provided.
[0032]
The air vent holes are provided at substantially the same position in the reverse direction, but a
plurality of air vent holes may be provided.
[0033]
In addition, for example, above the mold, a light source 5 for emitting ultraviolet light and / or
visible light is provided.
If the light source 5 is provided on both the upper and lower sides, the curing time can be
shortened by irradiating the light 6.
[0034]
Next, one production example of the diaphragm according to the present invention will be
described.
[0035]
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First, as shown in FIG. 3, the upper mold 2 is positioned on the lower mold 1 and clamped, and
the nozzle 7 for ejecting the photocurable resin is brought close to the gate 4 on the side surface
of the mold.
[0036]
Next, as shown in FIG. 4, the nozzle 7 is inserted into the gate 4, and the clearance 3 in the mold
is filled with the photocurable resin 8.
The air present in the clearance 3 is exhausted to the outside from the air vent hole on the
opposite side as the resin is filled.
[0037]
FIG. 5 shows a state in which the photocurable resin 8 is filled from the gasket portion 3c toward
the edge portion 3b.
[0038]
FIG. 6 shows a state in which the photocurable resin 8 is filled up to the diaphragm body 3a.
[0039]
After the resin filling, as shown in FIG. 2, the resin 8 is cured by irradiating light 6 consisting of
ultraviolet light and / or visible light for a predetermined time through the light source 5.
[0040]
After curing of the resin, mold opening may be performed, and the molded diaphragm having a
predetermined shape may be taken out.
[0041]
In the above, liquid resin 8 in an uncured state is made of glass, carbon, inorganic fibers such as
aramid, organic fibers, fine particles such as mica, basic magnesium sulfate whiskers, carbon
nanotubes, carbon nanofibers, fullerenes, etc. It is possible to obtain a diaphragm having various
physical properties which can not be obtained by using the resin alone by blending in advance
and injecting into the clearances of upper and lower molds and irradiating ultraviolet light and /
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or visible light.
[0042]
Various combinations of the materials to be compounded and the resin materials curable by
ultraviolet light and / or visible light can be used, and a diaphragm having desired physical
properties can be optionally obtained.
[0043]
In addition, by adjusting the amount of mold closing, the amount of clearance can be easily
adjusted, and a diaphragm having a desired thickness can be manufactured.
[0044]
Second Embodiment The diaphragm is required to have high elasticity, appropriate internal loss,
rigidity, and light weight.
[0045]
Further, as the conditions required for the edge provided on the outer periphery of the
diaphragm, the linearity with respect to the input signal is good, it is difficult to cause the reverse
resonance phenomenon, it is reliable, it is lightweight, and its manufacture is easy. Etc.
[0046]
In the above embodiment, the diaphragm and the edge are integrated.
For this reason, manufacture is easy.
[0047]
However, since the edge and the diaphragm are the same material, the desired performance may
not be obtained.
[0048]
On the other hand, this embodiment is characterized in that the edge is easily integrated with a
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separately formed diaphragm body to manufacture a diaphragm having desired characteristics.
[0049]
That is, as the material of the diaphragm body, materials having desired characteristics are
selected from paper-made products, resin molded products, metal molded products, composite
products thereof, etc. according to the purpose or application, etc. The mold is set and closed,
and the photocurable resin is filled through the gate into the clearance outer peripheral portion
to be the edge portion, and the structure is integrated by irradiating light and curing.
[0050]
In this case, the gasket may be integrated.
[0051]
In this way, a diaphragm having desired characteristics can be easily obtained, and a
photocurable resin can be appropriately filled in a desired amount as in the embodiments
described above, and the diaphragm body and the edge Since it is not necessary to use an
adhesive when integrating, it is possible to obtain stable characteristics without causing
variations in applied amount and variations in adhesive strength.
Moreover, the process of application ¦ coating of an adhesive agent, bonding, and hardening
aging can be skipped, and a man-hour can be reduced.
[0052]
Next, a method of manufacturing a diaphragm according to the second embodiment will be
described.
[0053]
First, as shown in FIG. 7, the diaphragm body 9 is inserted into a predetermined portion of the
surface of the lower mold 1, and the upper mold 2 and the lower mold 1 are clamped.
[0054]
Next, as shown in FIG. 8, the nozzle 7 is brought close to the gate 4 of the upper and lower mold,
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and as shown in FIG. 9, a photocurable resin is applied to the gasket portion 3 c of the clearance
outer peripheral part of the mold via the gate 4 Fill 8
[0055]
As shown in FIG. 10, the filled photocurable resin 8 is filled from the gasket portion 3c toward
the inner edge portion 3b.
During this process, internal air is exhausted from the air vent (not shown).
[0056]
Then, as shown in FIG. 10, the edge portion 3b is filled, and as shown in FIG. 11, the filling is
completed in the state of reaching the outer peripheral portion of the diaphragm body 9.
[0057]
Thereafter, light may be irradiated to cure the photocurable resin 8, and after curing, the mold
may be opened, and the gasket and the diaphragm in which the edge is integrated with the
diaphragm body 9 may be taken out.
[0058]
In each of the above embodiments, the gasket portion 3c is provided on the outer peripheral
portion of the clearance and the gasket is integrally formed, but it goes without saying that the
shape of the clearance may be limited to the edge portion 3b.
[0059]
Also, conversely, a metal, paper, or resin molded gasket is first set in the gasket part 3c on the
outer periphery of either the upper mold 2 or the lower mold 1 and then clamped, and a
photocurable resin It may be filled through a gate provided at an appropriate place, irradiated
with light and cured, and simultaneously molded with the diaphragm body and the edge.
[0060]
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The half cross section of the lower mold ¦ type and upper mold ¦ type which are used for 1st
Example of this invention is shown.
Explanatory drawing of the state which clamped the upper and lower type ¦ mold of the Example
of the same as above is shown.
Explanatory drawing of the manufacturing process of 1st Example of this invention is shown.
The explanatory drawing of the next manufacturing process of 1st Example of this invention is
shown.
An explanatory view of a further next manufacturing process of the first embodiment of the
present invention is shown.
The explanatory view in the state where the photocurable resin was completely filled in the
clearance in a mold in the manufacturing process of a 1st example of the present invention is
shown.
Explanatory drawing of the manufacturing process of 2nd Example of this invention is shown.
Explanatory drawing of the manufacturing process of an Example same as the above is shown.
Similarly, an explanatory view of a manufacturing process is shown.
Similarly, an explanatory view of a manufacturing process is shown.
The state which the photocurable resin with which the diaphragm body of the shaping ¦ molding
die was filled was joined is shown.
Explanation of sign
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[0061]
DESCRIPTION OF SYMBOLS 1 lower mold 2 upper mold 3 clearance 3 a diaphragm body 3 b
edge part 3 c gasket part 4 gate 5 light source 6 light 7 nozzle 8 light curing resin 9 diaphragm
body
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