KR101719951B1 - The speaker by using cellulose film - Google Patents

Abstract

The present invention provides a speaker using a cellulose film which includes: a magnet for generating a magnetic field through an electric current; a voice coil for generating a magnetic field when an electric signal is input, the voice coil vibrating according to interference with the magnetic field generated by the magnet; a vibration plate attached to the voice coil and vibrating together with the voice coil to generate sound, the vibration plate being provided in a multilayer structure; a plate attached to the magnet for inducing a magnetic flux generated from the magnet to the voice coil; and a pole piece for providing a magnetic path of the magnetic flux generated by the magnet together with the magnet and the plate, wherein at least one layer of the vibration plate having the multi-layer structure is formed of a cellulose film. According to the present invention, since at least one layer of the vibration plate having a multi-layer structure is formed of a cellulose film and has excellent elasticity, heat resistance and tensile strength, the acoustic quality of the speaker is substantially improved. In addition, since at least one layer of the vibration plate having a multilayer structure is formed of a cellulose film, which is a natural polymer, it is harmless to the human body and may be recycled, and the manufacturing cost may be reduced.

Description

The present invention relates to a speaker using cellulose film,

The present invention relates to a speaker using a cellulose film.

Cellulose is one of the most renewable and abundant natural polymeric materials available from biomass and accounts for 40 to 50% of the chemical composition of almost all plants.

In addition, such a cellulose has attracted much attention due to advantages such as excellent mechanical properties, low density and biodegradability, and is widely used as a fibrous material having high strength and elasticity per unit weight.

However, when water is used as a coagulating liquid in the production of a cellulose film rather than a cellulose fiber, large pores are formed in the film during coagulation and it is difficult to obtain a uniform film.

To solve such a problem, Korean Patent Registration No. 10-1123952 (hereinafter referred to as "prior art") and the like are known. The prior art discloses a method for producing a cellulose film and a cellulose film produced by the method.

Specifically, in the prior art, various kinds of cellulose are manufactured from a high-density cellulose film to a porous cellulose film having a high porosity by adding and controlling a small amount of water to the alcohol-based solvent. In the film casting process, By applying the knife edge method, it is possible to manufacture a thin film having a thickness of 0.01 to 0.03 mm.

However, according to the prior art, since the tensile strength in each direction is not constant due to the production of a cellulose film using NMMO (N-methylmorpholine-N-oxide) as a solvent, the isotropic property is low and the tensile strength is low. .

It is an object of the present invention to provide a loudspeaker provided with a multi-layer diaphragm using a cellulose film having a constant tensile strength and ensuring isotropy.

According to an aspect of the present invention, there is provided a speaker using a cellulose film, comprising: a magnet for generating a magnetic field through a current; A voice coil which generates a magnetic field through an input of an electric signal and vibrates according to an interference with a magnetic field generated by the magnet; A diaphragm attached to the voice coil and vibrating together with the voice coil to generate sound, the diaphragm being provided in a multilayer structure; A plate attached to the magnet, attached to the magnet, for guiding the magnetic flux generated through the magnet to the voice coil side; And a pole piece for providing a magnetic path of magnetic flux generated through the magnet together with the magnet and the plate, wherein at least one layer of the multi-layer diaphragm is formed of a cellulose film .

Here, the cellulose film is prepared by preparing a cellulose solution prepared by mixing pulp, dimethylacetamide solution and lithium chloride, in the form of a film.

Also, the cellulose solution may contain 1 to 1.5 parts by weight of the pulp; 90 to 92 parts by weight of the dimethylacetamide solution; And 8 to 9 parts by weight of the lithium chloride.

The cellulose film is characterized in that it is formed into a film by curing by spraying a solution for curing into the cellulose solution.

In addition, the curing solution is characterized by containing isopropyl alcohol (IPA).

In addition, the thickness of the cellulose film is set to 10 to 100 탆.

The present invention has the following effects.

First, since at least one layer of the diaphragm having a multi-layer structure is provided as a cellulose film, the elasticity, heat resistance and tensile strength of the diaphragm are excellent, so that the acoustic quality of the overall speaker is improved.

Second, since at least one layer of the diaphragm having a multilayer structure is made of a cellulose film, which is a natural polymer, it is harmless to the human body and can be recycled, and manufacturing cost can be reduced.

1 is a cross-sectional view schematically showing a speaker using a cellulose film according to an embodiment of the present invention.
2 is a flowchart illustrating a method of manufacturing a cellulose film according to an embodiment of the present invention.
3 is a flowchart illustrating a method of manufacturing a cellulose solution according to an embodiment of the present invention.
4 is a flowchart illustrating a method for producing a mixed solution of lithium chloride and dimethylacetamide according to an embodiment of the present invention.
5 is a flowchart illustrating a method of manufacturing a cellulose film according to an embodiment of the present invention.
6 is a graph showing the tensile strength of a cellulose film according to an embodiment of the present invention.
7 is a graph showing storage modulus of a cellulose film according to an embodiment of the present invention.
8 is a graph showing a storage modulus of a PET film according to a comparative example of the present invention.

Hereinafter, a detailed description of related art will be omitted if it is determined that the gist of the present invention may be unnecessarily obscured. In addition, numerals used in the description of the present invention are merely an identifier for distinguishing one component from another.

In addition, the terms used in the specification and claims should not be construed in a dictionary meaning, and the inventor may, on the principle that the inventor can properly define the concept of a term in order to explain its invention in the best way, And should be construed in light of the meanings and concepts consistent with the technical idea of the present invention.

Therefore, the embodiments shown in the present specification and the drawings are only exemplary embodiments of the present invention, and not all of the technical ideas of the present invention are presented. Therefore, various equivalents It should be understood that water and variations may exist.

The preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

≪ Explanation of Speaker Using Cellulose Film >

1 is a cross-sectional view schematically showing a speaker using a cellulose film according to an embodiment of the present invention.

1, a speaker 100 using a cellulose film according to an embodiment of the present invention includes a magnet 110, a voice coil 120, a diaphragm (not shown) 130, a plate 140, and a pole piece 150.

The magnet 110 generates a magnetic field through a current and can be provided as a permanent magnet and can generate and maintain a stable magnetic field without receiving energy from the outside.

The voice coil 120 is disposed between the magnet 110 and the pole piece 150. The voice coil 120 generates a magnetic field by an electric signal inputted thereto and vibrates according to interference with a magnetic field generated by the magnet 110. [

Here, the voice coil 120 may be formed by winding a coil of a copper, aluminum, or the like wrapped with an insulating layer and a folding layer on a bobbin, and by applying a magnetic field generated from the magnet 110 when an electric signal is applied A driving force is generated and oscillates in the vertical direction.

The diaphragm 130 is attached to the voice coil 120 to vibrate together with the voice coil 120 to generate sound, and has a multi-layer structure. At least one layer of the multi-layer diaphragm (hereinafter, referred to as 'multi-layer diaphragm') 130 is formed of a cellulose film.

The cellulose film may be a polymer film used for a speaker multi-layer diaphragm 130, a film made of polyethylene terephthalate (PET), a film made of polyetheretherketone (PEEK), a film made of polyimide imide (PI) material, polyethylene naphthalate (PEN) material, and polyethylene imine (PEI) material can be used instead of the material of the multi-layer diaphragm 130 can do.

In addition, since the cellulose film to be applied to the multilayered diaphragm 130 of the present invention is stretched by biaxial stretching, it is possible to ensure isotropic tensile strength in each direction. Therefore, tensile strength, Elasticity and heat resistance, but also can be recycled as an eco-friendly material harmless to the human body by being provided on the basis of cellulose, and the manufacturing cost can be reduced.

The plate 140 is attached to the magnet 110 and guides the magnetic flux generated in the magnet 110 to the voice coil 120 side.

The pole pieces 150 are configured to provide a magnetic path of magnetic flux generated through the magnet 110 together with the magnet 110 and the plate 140.

≪ Explanation of production method of cellulose film >

FIG. 2 is a flow chart illustrating a method for producing a cellulose film according to an embodiment of the present invention. FIG. 3 is a flowchart illustrating a method for producing a cellulose solution according to an embodiment of the present invention. FIG. 5 is a flow chart showing a method of manufacturing a cellulose film according to an embodiment of the present invention. FIG. 5 is a flowchart illustrating a method of manufacturing a mixed solution of lithium chloride and dimethylacetamide according to the present invention.

The speaker using the cellulose film according to the embodiment of the present invention will be described in detail with reference to the flowcharts shown in FIGS.

The cellulose film is prepared in the form of a film in the form of a cellulose solution prepared by mixing pulp, dimethylacetamide solution and lithium chloride, which will be described below in detail. .

1. Cellulose solution preparation step < S100, Step A >

In this step, a cellulose solution is prepared using pulp, water, dimethyl acetamide solution and lithium chloride.

Here, as shown in FIG. 3, this step is a pulp pretreatment step (S 110, step A-1); A mixed solution preparation step (S120, step A-2); Pulp and mixed solution stirring step (S130, step A-3) are sequentially performed, and the respective steps will be described in detail as follows.

First, in the pulp pretreatment steps (S110 and A-1), pulp is added to water and dimethylacetamide solution sequentially to perform pretreatment for the pulp.

Here, the pulp is processed by chemical refining to increase the purity of the cellulose. The pulp may be prepared as a dissolving pulp corresponding to paper pulp for forming a fiber and a film, and is generally manufactured by digesting wood.

Specifically, in the pulp pretreatment step (S110, step A-1), the pulp is cut or torn into a predetermined size and immersed in water for 12 hours or more. At this time, care should be taken not to introduce dust or impurities. Here, the water to be used is preferably purified water (Deionized water or DI water) free of impurities or ions to produce a high quality cellulose solution. In this step, 7.5 g of pulp was immersed in 375 g of water.

Thereafter, in this step, the pulp immersed in water for more than 12 hours is removed, the water is sufficiently removed, and then immersed in a dimethylacetamide solution for at least 2 hours to replace the water that has penetrated into the pulp with a dimethylacetamide solution. Here, the dimethylacetamide solution is a slightly acidic solvent for dissolving pulp, and dimethylacetamide having a purity of 99.5% or more should be used. In this step, 7.5 g of pulp was immersed in 375 g of dimethylacetamide. In this step, it is preferable that the pulp is immersed in the dimethylacetamido solution and the process of replacing the pulp is repeated one more time to completely replace the water permeated into the pulp with the acetamide solution. Thus, in the pulp pretreatment step (S110, A Step-1) is completed. Here, the immersion order of the water and the dimethylacetamide solution, which are the solvents for pretreating the pulp, should be changed or omitted in succession without omission.

Next, in the mixed solution preparing step (S120, step A-2), a process for preparing a mixed solution is performed by dissolving lithium chloride in dimethylacetamide solution.

Here, as shown in FIG. 4, the mixed solution preparing step (steps S120 and A-2) includes a step of drying lithium chloride (steps S121 and A-2-1); Dimethyl acetamide heating step (S122, step A-2-2); And stirring step (S123, step A-2-3), and the above-described steps are sequentially performed.

First, in the step of drying lithium chloride (S121, step A-2-1), lithium chloride is dried in an oven. Specifically, 42.5 g of lithium chloride is weighed and placed in a beaker and dried in an oven at a temperature of 105 to 115 ° C for 1 to 2 hours. This process removes moisture in the lithium chloride.

Then, in the heating step of dimethylacetamide (S122, step A-2-2), a step of heating the dimethylacetamide solution is performed. Specifically, 450 g of dimethylacetamide solution is placed in a beaker, heated, and heated so that the temperature of dimethylacetamide reaches 80 캜.

Then, the stirring step S123 (A-2-3) is performed by heating the dimethylacetamide solution (S121, A-2-2) Step 2-1) is performed to stir the dried lithium chloride. Through this process, a mixed solution comprising dimethylacetamide and lithium chloride is produced. Here, the mixed solution is prepared by mixing 50 to 70 parts by weight of dimethylacetamide; And 5 to 6.5 parts by weight of lithium chloride; 60 parts by weight of dimethylacetamide; And 5.7 parts by weight of lithium chloride.

Specifically, 450 g of dimethylacetamide solution was added to 42.5 g of lithium chloride in a beaker and stirred while heating for 2 to 3 hours. When the heating was stopped after the above-mentioned period of time and lithium chloride was not precipitated in the dimethylacetamide solution Lt; / RTI &gt; In addition, the lithium chloride dried through the step of drying lithium chloride (S121, step A-2-1) is taken out of the oven and then placed in a dimethylacetamide solution. The lithium chloride is collected and stirred by a spoon or a glass rod It is preferable to crush the lithium clyde.

Finally, pulp and mixed solution stirring steps S130 and A-3 are performed by mixing pulp pretreated through the pulp pretreatment steps (S110 and A-1) and the mixed solution preparing step (steps S120 and A-2) And stirring the mixed solution prepared through the above process.

That is, in this step, pulp pretreated through pulp pretreatment steps (S110 and A-1) is added to the mixed solution of lithium cide and dimethylacetamide through a mixed solution preparation step (S120 and A-2) Stirring process is performed. Here, it is preferable to set the minimum speed of the impeller of the stirrer to 70 rpm and stir for about 4 days for proper stirring. Also, in this stirring process, since the pulp is sensitive to moisture, the container used for stirring should be sealed and agitated in order to minimize permeation of moisture.

Since pulp pretreated through the pulp pretreatment step (S110, step A-1) was immersed in a dimethylacetamide solution, it was necessary to remove dimethylacetamide sufficiently before the stirring step of this step was performed, It is necessary to stir the mixed mixed solution through steps S120 and A-2. This is because when the amount of dimethylacetamide used in the pulp pretreatment remains large in the pulp, the amount of dimethylacetamide in the mixed solution may be varied when the liquid is mixed with the mixed solution, .

Therefore, in this step, the cellulose solution having a high viscosity can be produced by stirring the pulp and the mixed solution in consideration of the above-mentioned matters.

2. Cellulose film production step < S200, Step B >

In this step, a cellulose solution prepared through the cellulose solution preparation step (S100, step A) is prepared into a film, followed by biaxial stretching and drying to prepare a cellulose film.

Here, as shown in FIG. 5, this step is a cellulosic solution applying step (S210, step B-1); A cellulose solution curing step (S220, step B-2); A wet film production step (S230, step B-3); And a wet film stretching and drying step (steps S240 and B-4) are sequentially performed, and the respective steps will be described in detail as follows.

First, the cellulose solution applying step (S210, step B-1) is a process of uniformly applying the cellulose solution prepared through the cellulose solution preparing step (S100, step A) to the PET film surface by the film casting method .

Specifically, a doctor blade was fixed on a PET film having a thickness of 75 μm mounted on a casting apparatus, and a cellulose solution prepared through a cellulose solution preparation step (S100, step A) was poured onto a doctor blade, .

Then, the cellulose solution solution is cured by spraying the solution for curing to the cellulose solution coated on the surface of the PET film through the cellulose solution application step (S210, B-1) The process is done.

Here, the curing solution may be prepared by mixing water (DI water) and isopropyl alcohol (IPA), and the mixing ratio (volume) of water and isopropyl alcohol is preferably 1: 1 .

The conditions of the casting apparatus used in the above steps were set to the injection nozzle: Danfoss 0.50 80H, the nozzle interval 11 cm, the casting speed 0.3 to 0.4 (m / min), and the angle of the conveyor belt 4 And each process was carried out.

Specifically, when the cellulose solution spreads evenly on the doctor blade of the casting apparatus, the solution is transported to the place where the nozzle is mounted using the conveying belt of the casting apparatus, and the solution for hardening is uniformly sprayed through the nozzle to cure the cellulose solution.

Then, the wet film production step (S230, step B-3) is performed by immersing the PET film, in which the cellulose solution is cured, in the water through the cellulose solution curing step (steps S220 and B-2) . That is, the sheet (PET film in which the cellulose solution is cured) formed through the above step is moved to a storage tank storing DI water to immerse it.

Finally, in the wet film stretching and drying steps (S240 and B-4), the wet film produced through the wet film production steps (S230 and B-3) is biaxially stretched and dried. Here, it is preferable that the cellulose film produced through this step is provided in a thickness of 10 to 100 탆 in order to provide tensile strength and elasticity.

The reason why the wet film produced through the wet film production steps (S230 and B-3) in this step is biaxially stretched will be explained. When the cellulose film is used for the multilayer diaphragm 130 of the speaker, Strength is very important because if stretched by biaxial stretching using a stretching device, it is possible to ensure isotropy by making the tensile strength constant in each direction. The multilayered diaphragm 130 including the cellulose film is harmless to the human body and can be recycled. In addition, since the multilayered diaphragm 130 including the cellulose film is used in various directions The tensile strength is constant and excellent, and the elasticity is excellent.

In addition, when used as an outer layer of the multilayered diaphragm 130, the cellulose film produced as described above has hydrophilicity due to its material properties, so that the surface of the cellulose film is subjected to post treatment such as plasma treatment so as to have hydrophobicity It is preferable to use it by processing.

< Example >

6 is a graph showing the tensile strength of a cellulose film according to an embodiment of the present invention.

ASTM D882-12 (Standard Test Method for Tensile Properties of Thin Plastic Sheeting) measurement was conducted to measure the tensile strength of a cellulose film containing at least one or more layers in a multilayered diaphragm 130 of a speaker 100 using the cellulose film of the present invention The mechanical properties test was carried out using the method. The instrument used for this mechanical property test was the 'universal material testing machine'.

First, a cellulose film was cut in a longitudinal direction and a transverse direction using a specimen cutter to prepare a sample (thickness 10 mu m) having a uniform size of 2 cm in width and 10 cm in length. The prepared sample was mounted at a depth of about 2 cm on the upper and lower grips of the universal testing machine so that it could be fixed.

The height of the tensile test direction of the thus prepared sample was measured using vernier calipers, and the tensile speed of the sample was set at 1 (mm / min).

Here, when the sample was fixed to the upper and lower grips of the universal material testing machine, the horizontal and vertical directions of the sample were arranged so as to be aligned, and the average value measured by repeating the thickness and height of the sample five times was used.

The results of measuring the physical properties of the cellulose films (samples) of Examples 1 to 4 according to the present invention are summarized in the following Table 1, and the respective tensile strengths of Examples 1 to 4 A graph of strength (maximum stress and extension) is shown in FIG.

yield point Maximum point Breaking point weight Displacement distance burglar Modulus of elasticity weight burglar Elongation weight Elongation distance Example 1 12.51 2.63 52.13 2435.41 25.67 106.96 10.13 25.67 6.08 Example 2 12.85 1.79 53.53 3480.41 24.62 102.59 7.33 24.62 4.40 Example 3 14.42 1.42 60.10 4755.08 30.54 127.27 8.24 30.54 4.94 Example 4 12.35 1.39 51.47 4008.94 27.49 114.54 8.33 27.49 5.00 Average 13.03 1.81 54.31 3669.96 27.08 112.84 8.51 27.08 5.11 unit N mm MPa MPa N MPa % N mm

As shown in Table 1, it can be seen that the tensile strength is excellent due to the maximum point stress and the extension, and it can be seen that the elasticity is high and the elasticity is excellent. In particular, it was found that the average of the maximum point intensities (average of Examples 1 to 4) was 112.84 MPa (or 16.38 ksi), and the average of the stretching distances (the average of Examples 1 to 4) .

The multilayered diaphragm 130 should be excellent in tensile strength and elasticity so that the multilayered diaphragm 130 is not deformed or torn due to negative pressure. Since the cellulose film of the present invention has excellent mechanical properties such as tensile strength and elasticity, It is very suitable for use as the multilayer diaphragm 130.

Therefore, the cellulose film used in the multilayered diaphragm 130 of the present invention may be attached to at least one outer layer or inner layer of the multilayered diaphragm 130 to provide the tensile strength and elasticity of the multilayered diaphragm 130, Since the multilayer diaphragm 130 can be made lightweight, harmless to the human body, and recyclable, the multilayer diaphragm 130 is very suitable for use in a speaker multilayer diaphragm 130, and the manufacturing cost of the multilayer diaphragm 130 can be reduced.

FIG. 7 is a graph showing storage modulus of a cellulose film according to an embodiment of the present invention, and FIG. 8 is a graph showing storage modulus of a PET film according to a comparative example of the present invention.

Since the internal loss of the cellulose film used for the multilayer diaphragm 130 is related to tan delta, loss elastic modulus and storage modulus, the internal loss of the cellulose film can be known through the storage elastic modulus. (tan delta = loss elastic modulus / storage elastic modulus)

As shown in FIG. 8, the polyethylene terephthalate (PET) film has a constant storage elastic modulus (GPa) which is not constant depending on temperatures of 30 ° C, 40 ° C, 50 ° C and 60 ° C Since the internal loss value also varies with temperature, the PET film is not effective for applying to the multilayer diaphragm 130.

On the other hand, the cellulose film of the present invention maintains a constant storage elastic modulus (GPa) value at temperatures of 30 ° C, 40 ° C, 50 ° C and 60 ° C as shown in FIG. 7, Value, so that it is very suitable to be applied to the multilayer diaphragm 130.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. And the scope of the present invention should be understood as the scope of the following claims and their equivalents.

100: Speaker with cellulose film
110: magnet
120: voice coil
130: diaphragm
140: Plate
150: Paul Pease

Claims (6)

As a speaker using a cellulose film,
A magnet for generating a magnetic field through an electric current;
A voice coil which generates a magnetic field through an input of an electric signal and vibrates according to an interference with a magnetic field generated by the magnet;
A diaphragm attached to the voice coil and vibrating together with the voice coil to generate sound, the diaphragm being provided in a multilayer structure;
A plate attached to the magnet for guiding the magnetic flux generated through the magnet to the voice coil side; And
And a pole piece for providing a magnetic path of magnetic flux generated through the magnet together with the magnet and the plate,
At least one layer of the diaphragm having the multilayer structure is formed of a cellulose film,
The cellulose film is prepared by preparing a cellulose solution prepared by mixing pulp, dimethylacetamide solution and lithium chloride, in the form of a film.
Speaker using cellulose film.
delete The method according to claim 1,
The cellulosic solution,
1 to 1.5 parts by weight of the pulp;
90 to 92 parts by weight of the dimethylacetamide solution; And
And 8 to 9 parts by weight of the lithium chloride.
Speaker using cellulose film.
The method according to claim 1,
Characterized in that the cellulose film is formed into a film by curing by spraying a solution for curing into the cellulosic solution
Speaker using cellulose film.
5. The method of claim 4,
Characterized in that the curing solution contains isopropyl alcohol (IPA)
Speaker using cellulose film.
The method according to claim 1,
And the thickness of the cellulose film is set to 10 to 100 占 퐉
Speaker using cellulose film.

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