close

Вход

Забыли?

вход по аккаунту

?

JP2001160998

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2001160998
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
diaphragm for a piezoelectric sounding body for supporting and vibrating a piezoelectric element
and a method of manufacturing the same.
[0002]
2. Description of the Related Art A piezoelectric speaker is used as a piezoelectric speaker which
comprises a piezoelectric element and a diaphragm supporting and vibrating with the
piezoelectric element. The material of the diaphragm is required to have conductivity enough to
supply a current sufficient to drive the piezoelectric element, and to have sufficient rigidity to
support the piezoelectric element even if light.
[0003]
Japanese Patent Application Laid-Open No. 4-22300 discloses that a carbon material is used as a
material of a diaphragm for a piezoelectric sounding body which responds to such a requirement.
[0004]
In recent years, attention has been focused on the fact that piezoelectric speakers are small and
energy saving can be realized, and distortion of the sound is so small as to be comparable to
11-05-2019
1
dynamic speakers, the reproduction range is wide, and clear sound quality is realized. If the
piezoelectric sounding body which can be reproduced and which is compact can be realized, it is
expected that the application will be further expanded.
[0005]
In this case, the thickness of the diaphragm needs to be reduced to 100 μm or less in order to
maintain a wide reproduction range without distortion even if the diameter of the diaphragm is
reduced for downsizing and energy saving. At this time, without sufficient rigidity, there is a
problem that the piezoelectric element can not be supported.
Although Japanese Patent Publication No. 7-108035 discloses a speaker diaphragm made of a
composite carbon material obtained by firing a carbon precursor containing graphite, the
disclosed diaphragm is a general speaker. This is a dome-shaped or cone-shaped diaphragm for
the purpose of improving the sound quality of a diaphragm for a piezoelectric element
supporting a piezoelectric element, and does not give any suggestion to miniaturize and
miniaturize energy.
[0006]
Therefore, an object of the present invention is to provide a vibration for a piezoelectric sounding
body which is small in distortion of sound, capable of reproducing in a wide reproduction sound
range, with clear sound quality, and capable of producing a smaller piezoelectric speaker than
conventional. It is in providing a board and its manufacturing method.
[0007]
SUMMARY OF THE INVENTION According to the present invention, a diaphragm for a
piezoelectric speaker is provided which contains amorphous carbon and crystalline carbon and
has a shape suitable to support and vibrate with the piezoelectric element.
According to the present invention, there is also provided a method of manufacturing a
diaphragm for a piezoelectric sounding body, wherein a polymer resin and graphite are mixed
and formed into a desired shape and then fired to support the piezoelectric element and to make
the shape suitable for vibrating with it Also provided.
11-05-2019
2
[0008]
It is preferable to control the orientation of the graphite in one direction during the abovementioned molding.
The graphite is preferably selected from highly oriented pyrolytic graphite having an average
particle diameter of 100 μm or less, kish graphite, natural graphite, and artificial graphite, and
preferably exhibits high crystallinity. The above-mentioned firing is preferably performed in an
inert atmosphere, a non-oxidative atmosphere, or in vacuum at a temperature of 1000 ° C. or
higher.
[0009]
DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross-sectional view showing a
state in which a diaphragm made of a composite carbon material of amorphous carbon and
graphite according to one embodiment of the present invention is used for a piezoelectric
speaker. The piezoelectric element 10 is fixed to a diaphragm 12 made of a composite carbon
material, and the periphery of the diaphragm 12 is fixed to a housing 14. By applying an
electrical signal 16 between the surface of the piezoelectric element 10 not fixed to the
diaphragm 12 and the diaphragm 12, the piezoelectric element 10 is deformed, and the
deformation is transmitted to the diaphragm 12 to vibrate the diaphragm 12 Do.
[0010]
The process of manufacturing the diaphragm 12 will be described below as Examples 1 to 4.
(Example 1) 20% by mass of chlorinated vinyl chloride resin (T-741 manufactured by Nippon
Carbide Co., Ltd.), 30% by mass of furan resin (manufactured by Hitachi Chemical Co., Ltd.
Hitafuran VF-302) as a polymer resin To a composition consisting of 50% by mass of powder
(manufactured by Nippon Graphite Co., Ltd., average particle size 5 μm), 20% by mass of diallyl
phthalate monomer is added as a plasticizer, dispersed using a Henschel mixer, and two rolls for
mixing After repeated kneading sufficiently, a film having a thickness of 100 μm was formed by
a film forming machine. The resulting film is shaped into a disk with a diameter of 20 mm using
a vacuum forming machine, fixed to a jig and treated in an air oven heated to 180 ° C. for 10
11-05-2019
3
hours to form a carbon precursor gave. Next, this is heated in a nitrogen gas at 100 ° C. at a
temperature rising rate of 25 ° C./hour, then at 1500 ° C. at a temperature of 100 ° C./hour,
at 1500 ° C. for 3 hours After holding, it was naturally cooled to complete baking.
[0011]
The obtained carbon-based vibration plate had a diameter of 16 mm, a thickness of 60 μm, a
density of 1.75 g / cm 3, an elastic modulus of 150 GPa, and a sound velocity of 9.2 km / sec.
(Example 2) 45% by mass of chlorinated vinyl chloride resin (T-741 manufactured by Nippon
Carbide Co., Ltd.) as a polymer resin, and a composition comprising 55% by mass of natural
graphite fine powder (manufactured by Nippon Graphite Co., Ltd. average particle size 10 μm)
To the product, 25% by mass of diallyl phthalate monomer is added as a plasticizer and dispersed
using a Henschel mixer, and after sufficient kneading repeatedly using a two-roll mixing machine,
the film thickness is 100 μm. The film was formed. The resulting film is shaped into a disk with
a diameter of 20 mm using a vacuum forming machine, fixed to a jig and treated in an air oven
heated to 150 ° C. for 10 hours to form a carbon precursor gave. Next, this is heated in a
nitrogen gas at 100 ° C. at a temperature rising rate of 25 ° C./hour, then at 1500 ° C. at a
temperature of 100 ° C./hour, at 1500 ° C. for 3 hours After holding, it was naturally cooled to
complete baking.
[0012]
The obtained carbon-based vibration plate had a diameter of 15 mm, a thickness of 50 μm, a
density of 1.85 g / cm 3, an elastic modulus of 270 GPa, and exhibited a sound velocity of 12.0
km / sec. (Example 3) 45% by mass of vinyl chloride resin / vinyl acetate resin copolymer
(C705A, manufactured by Shin-ichi Daiichi Vinyl Co., Ltd.), 15 mass% of furan resin (Hitafuran
VF, manufactured by Hitachi Chemical Co., Ltd.), as a polymer resin 20% by mass of diallyl
phthalate monomer as a plasticizer is added to a composition comprising 40% by mass of
artificial graphite fine powder (average particle size 5 μm manufactured by SSC Co., Ltd.) and
dispersed using a Henschel mixer for mixing 2 After sufficient kneading was repeated using this
roll, a film with a thickness of 100 μm was formed by a film forming machine. The resulting film
is shaped into a disk with a diameter of 20 mm using a vacuum forming machine, fixed to a jig
and treated in an air oven heated to 130 ° C. for 10 hours for carbon precursor conversion
treatment gave. Next, this is heated in a nitrogen gas at 100 ° C. at a temperature rising rate of
25 ° C./hour, then at 1500 ° C. at a temperature of 100 ° C./hour, at 1500 ° C. for 3 hours
After holding, it was naturally cooled to complete baking.
11-05-2019
4
[0013]
The obtained carbon-based vibration plate had a diameter of 16 mm, a thickness of 60 μm, a
density of 1.80 g / cm 3, an elastic modulus of 250 GPa, and exhibited a sound velocity of 11.7
km / sec. (Example 4) 85% by mass of furan resin (Hitachi Chemical Co., Ltd., Hitafuran VF-302)
as a polymer resin source, and a composition comprising 15% by mass of natural graphite fine
powder (manufactured by Nippon Graphite Co., Ltd., average particle size of 5 μm) are mixed
therewith After thoroughly mixing using a two-roll mill, 1.5% by mass of p-toluenesulfonic acid
was added as a curing agent and the mixture was sufficiently stirred, and then formed into a film
having a thickness of 100 μm by a coater type film forming machine. The obtained film is
shaped into a disk of 20 mm in diameter using a vacuum forming machine, fixed to a jig and
solidified in an air oven heated to 90 ° C., and then 10 hours at 150 ° C. Heat treated. Next,
this is heated in a nitrogen gas at 100 ° C. at a temperature rising rate of 25 ° C./hour, then at
1500 ° C. at a temperature of 100 ° C./hour, at 1500 ° C. for 3 hours After holding, it was
naturally cooled to complete baking.
[0014]
The obtained carbon-based vibration plate had a diameter of 16 mm, a thickness of 58 μm, a
density of 1.65 g / cm 3, an elastic modulus of 95 GPa, and exhibited a sound velocity of 7.6 km
/ sec.
[0015]
As described above, the carbon-based vibration plate for a piezoelectric speaker according to the
present invention is a crystal having high elasticity in amorphous carbon obtained by carbonizing
a polymer resin excellent in formability. By making the complex of amorphous carbon and
graphite obtained by controlling the orientation of highly developed graphite uniformly and in
one direction highly, the rigidity can be lightened, so that the sound transmission speed is fast
and the distortion of sound Is small, the reproduction range of sound is wide, and clear sound
quality reproduction is possible, which is useful as a diaphragm material for a piezoelectric
sounding body.
Furthermore, as compared with conventional carbon products, it is possible to provide products
efficiently and inexpensively, so the industrial value is very large.
11-05-2019
5
11-05-2019
6
Документ
Категория
Без категории
Просмотров
0
Размер файла
14 Кб
Теги
jp2001160998
1/--страниц
Пожаловаться на содержимое документа