JP2013115618A - Manufacturing method of speaker diaphragm and speaker diaphragm manufactured by the manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a speaker diaphragm with which an edge formed from a soft material can be stabilized with respect to chemicals while suppressing a change in acoustic characteristics, and a speaker diaphragm which is manufactured by the manufacturing method.SOLUTION: On a surface of an edge 12 formed from a soft material in a speaker diaphragm 10, a coating 13 of an inorganic compound is formed according to chemical vapor deposition. The coating of the inorganic compound, which does not affect chemicals, is formed on the surface of the edge, thereby stabilizing the edge with respect to the chemicals while suppressing a change in product characteristics. Furthermore, since the coating is formed according to chemical vapor deposition, processing can be performed without any product characteristic change such as dissolution, swelling or deformation.

Description

  The present invention relates to a method for manufacturing a speaker diaphragm used in an electroacoustic transducer such as a headphone or a microphone, which is a kind of acoustic equipment, and a speaker diaphragm manufactured by the manufacturing method.

  Headphones and earphones may adhere to various chemicals (in a broad sense) such as cosmetics, hairdressing products, food products such as pharmaceuticals, drinking water, sauces and oils, and detergents in daily life. There is a risk that changes in acoustic characteristics may occur due to abnormalities such as dissolution and swelling. For this reason, the material used for the speaker diaphragm is required to be stable without changing the product characteristics even if these chemicals adhere.

  However, materials that are stable with respect to these chemicals are limited, and even if formed with a stable material, product characteristics are not always satisfied. That is, the speaker diaphragm is required to have good conversion efficiency by reducing the natural vibration due to the divided vibration and resonance, and is required to be a light material having a high Young's modulus and a large internal loss. Since there are few materials that sufficiently satisfy these various requirements, surface treatment is usually applied to materials that satisfy product characteristics so that they are not affected by contact with chemicals. Yes.

  For example, Patent Document 1 discloses that surface treatment is performed on a diaphragm material for the purpose of improving physical properties. In the technique of Patent Document 1, natural silk fibers are used as a base material, a metal layer is provided on the surface by a chemical vapor deposition method, and coating with a heat-crosslinking resin is performed. Thereby, since the internal loss of a base material is high and rigidity can be improved, distortion is reduced and heat resistance and weather resistance can be improved.

Japanese Patent Laid-Open No. 5-183982

  Since the technique of Patent Document 1 coats the surface of the speaker diaphragm with a heat-crosslinking resin, it can be estimated that the effect of stabilizing against contact with chemicals can be obtained. However, improvement of the physical properties of the rigid material is the original purpose, and it is effective for the diaphragm body portion having rigidity. However, when the edge portion is formed of a flexible material, the rigidity increases and the minimum resonance frequency increases. End up.

  That is, in the free edge type diaphragm, two pieces of a diaphragm body portion using a material having rigidity that does not cause abnormal resonance and an edge portion using a low stiffness material to lower the minimum resonance frequency. Although the sound quality is improved by adopting the structure, when the rigidity of the edge portion is increased by the coating of the heat-crosslinking resin, the lowest resonance frequency is increased, and the sound quality is deteriorated.

  For example, fluorine treatment, silicone treatment, etc. are known as treatments that have an effect of stabilizing against contact with chemicals and do not affect the rigidity of flexible materials. Moreover, many types of solvents are organic solvents, and the base material is dissolved and swollen by the treatment.

  For this reason, there exists a subject that the acoustic characteristic of the diaphragm for speakers will change if it tries to stabilize with respect to chemicals with respect to a flexible material.

  The present invention has been proposed in view of the above, and an object of the present invention is to provide vibration for a speaker capable of stabilizing chemicals in an edge portion formed of a flexible material while suppressing a change in acoustic characteristics. It is providing the manufacturing method of a board, and the diaphragm for speakers produced by the manufacturing method.

  In order to solve the above-described problem, the speaker diaphragm manufacturing method of the present invention according to claim 1 is an inorganic material formed by chemical vapor deposition on the surface of the edge portion 12 formed of a flexible material in the speaker diaphragm 10. A film 13 of the compound is formed.

  According to a second aspect of the present invention, in the method for manufacturing a speaker diaphragm according to the first aspect, the chemical vapor deposition method is an inductively coupled plasma CVD method.

According to a third aspect of the present invention, in the method for manufacturing a speaker diaphragm according to the first or second aspect, the inorganic compound includes any one of SiO ₂ , SiON, and SiN.

  The invention according to claim 4 is the method for manufacturing a speaker diaphragm according to any one of claims 1 to 3, wherein the flexible material of the edge portion 12 is a vulcanized rubber, an elastomer, a woven fabric, or a nonwoven fabric substrate. It includes any material coated with rubber.

  The invention according to claim 5 is the method of manufacturing a speaker diaphragm according to any one of claims 1 to 4, wherein the film thickness of the inorganic compound film 13 is 25 nm or more and 400 nm or less, preferably 50 nm to 200 nm. It is the range of these.

  A sixth aspect of the present invention is a loudspeaker diaphragm manufactured by the loudspeaker diaphragm manufacturing method according to any one of the first to fifth aspects.

  According to the first aspect of the present invention, since an inorganic compound film that does not affect chemicals is formed on the surface of the edge portion formed of the flexible material in the diaphragm, the product required for the edge portion. It is possible to stabilize chemicals while suppressing changes in properties. Further, since the film is formed by the chemical vapor deposition method, it is possible to perform a treatment that does not change the product characteristics such as dissolution, swelling, and deformation.

  According to the invention which concerns on Claim 2, a normal pressure and low temperature process are possible by using the inductively coupled plasma CVD method, and the quality change and characteristic change of the flexible material of an edge part can be suppressed.

As described in claim 3, as the inorganic compound, SiO ₂ , SiON, SiN or the like can be used.

  As described in claim 4, as the flexible material for the edge portion, a material obtained by coating rubber on a vulcanized rubber, an elastomer, a woven fabric, or a nonwoven fabric substrate can be used.

  According to the invention which concerns on Claim 5, tolerance with respect to chemicals is acquired, and a product characteristic is not affected.

  According to the sixth aspect of the present invention, it is possible to provide a speaker diaphragm that is stable without changing its acoustic characteristics even when chemicals adhere.

It is process drawing for demonstrating the manufacturing method of the diaphragm for speakers concerning the Example of this invention. The diaphragm produced with the manufacturing method shown in FIG. 1 is shown, (a) A figure is a top view, (b) A figure is the sectional view on the AA line of FIG. FIG. 3 is a cross-sectional view illustrating a configuration example of a speaker (headphone driver) using the diaphragm illustrated in FIG. 2. It is a figure for demonstrating the relationship between the thickness of the membrane | film | coat of an inorganic compound, and the tolerance with respect to chemicals. It is a figure for demonstrating the relationship between the thickness of the membrane | film | coat of an inorganic compound, and an acoustic characteristic (minimum resonance frequency).

  In the present invention, an inorganic compound film is formed on a surface of an edge portion formed of a flexible material in a speaker diaphragm by a chemical vapor deposition (CVD) method. The diaphragm body and edge are formed in separate manufacturing processes, and after forming an inorganic compound coating on the surface of the edge, the edge is bonded to the outer periphery of the diaphragm body with an adhesive or by thermocompression bonding. Joining to form a diaphragm.

  Stabilization can be achieved by forming a coating of an inorganic compound that does not affect chemicals on the surface of the edge portion formed of a flexible material. By appropriately setting the film thickness of the inorganic compound film, it is possible to suppress changes in acoustic characteristics as the diaphragm. Further, since the film is formed by the chemical vapor deposition method, it is possible to perform a treatment that does not change the product characteristics such as dissolution, swelling, and deformation.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a process diagram for explaining a method of manufacturing a speaker diaphragm according to an embodiment of the present invention. In this example, a manufacturing method of a free edge structure in which the diaphragm body and the edge are formed and joined in different manufacturing processes is shown. 2A and 2B show a diaphragm manufactured by the manufacturing method shown in FIG. 1, wherein FIG. 2A is a plan view, and FIG. 2B is a cross-sectional view taken along line AA in FIG. .

  As shown in FIG. 1, the speaker diaphragm manufacturing method according to the embodiment of the present invention includes (a) a diaphragm body manufacturing process, (b) an edge manufacturing process, and (c) an edge surface. And (d) a step of joining the diaphragm body and the edge portion. Here, either the manufacturing process of the diaphragm body part of (a) or the manufacturing process of the edge part of (b) may be performed first.

(A) Manufacturing Process of Diaphragm Body The diaphragm body 11 can be made of various materials such as paper, polymer, metal, composite, and ceramics. The plate body part 11 is manufactured. Taking a paper-based material as an example, the pulp is produced by papermaking, drying, and heat pressing. At this time, pulp may be used as a main material, and other sub-materials may be mixed as a reinforcing material depending on the required acoustic characteristics. Polyester and the like are widely used for polymer materials.

  Then, if necessary, the surface of the diaphragm body 11 is coated with resin or the like to stabilize against contact with chemicals. Alternatively, the same effect can be obtained by beating the pulp into a fiber, mixing and dispersing the resin powder, and melting with heat during molding to fill the gap between the pulp and impregnate the diaphragm body 11. It is done.

(B) Manufacturing process of edge part The edge part 12 sets the sheet-like material containing flexible materials, such as vulcanized rubber and an elastomer of thickness of about 10-200 micrometers, to a thermoforming machine, and is about 100-200 degreeC. Then, the inner diameter of the edge portion 12 is removed by a press machine.

  Examples of the vulcanized rubber include styrene-butadiene rubber, nitrile-butadiene rubber, ethylene-propylene-terpolymer rubber, isoprene rubber, chloroprene rubber, isobutylene-isoprene rubber, ethylene-propylene rubber, and silicone rubber. Examples of the elastomer include polystyrene, polyolefin, polyurethane, polyester, polyamide, polybutadiene, ethylene-vinyl acetate, and polyvinyl chloride. Or you may use the flexible material which coated rubber etc. on the woven fabric or the nonwoven fabric base material.

(C) Film formation step of inorganic compound on edge surface The inorganic compound film 13 is formed on the surface of the edge 12 formed as described above by the chemical vapor deposition (CVD) method. . Since the flexible material is vulnerable to high pressure and high temperature, it is preferable to use inductively coupled plasma-CVD (ICP-CVD), which can be processed at normal pressure and low temperature, among CVD methods.

When depositing an inorganic compound such as SiO ₂ by the ICP-CVD method, the film is formed for about 10 minutes under the conditions of high-frequency power of 500 W, pressure of 0.1 Pa, and temperature of 50 ° C. with SiH ₄ , O ₂ , and N ₂ gas flow. A SiO ₂ film having a thickness of 200 nm can be formed.

Examples of the inorganic compounds, such as SiON or SiN in addition to SiO ₂ is preferred. Since the inorganic compound film 13 has no effect on chemicals, it does not change the product characteristics such as dissolution, swelling and deformation. However, since the rigidity is generally high, if the thickness of the edge portion 12 of the diaphragm 10 is more than necessary, the acoustic characteristics such as the elastic modulus and the minimum resonance frequency are changed.

  Therefore, considering the balance between the thickness that can withstand the chemicals and the thickness that does not affect the acoustic characteristics, the film thickness should be 25 nm or more so that the chemical characteristics can be obtained. It is 400 nm or less without influence, and more preferably in the range of 50 nm to 200 nm.

(D) Step of joining diaphragm body and edge portion After the above-described steps are completed, a step of joining the diaphragm body portion 11 and the edge portion 12 is performed using a known method. In this step, for example, the outer peripheral edge of the manufactured diaphragm body 11 and the inner peripheral edge of the edge 12 are bonded with an adhesive or the like.

  For example, a urethane-based adhesive can be used as the adhesive. As a result, as shown in FIGS. 2A and 2B, the outer peripheral edge of the diaphragm body 11 and the inner peripheral edge of the edge 12 having the inorganic compound coating 13 formed on the surface are joined. A diaphragm 10 having a two-piece structure is formed.

  FIG. 3 is a cross-sectional view illustrating a configuration example of the speaker (headphone driver) 1 using the diaphragm 10 illustrated in FIG. 2. The speaker 1 is a so-called internal magnet type, and is supported in a magnetic circuit 5 having a pot-type yoke 2, a magnet 3 and a disk-shaped pole plate 4 that also serves as a frame, and a magnetic gap of the magnetic circuit 5. A diaphragm body 11 having the voice coil 6 disposed below the bent part and an edge 12 joined to the outer peripheral edge of the diaphragm body 11 are provided. The diaphragm body 11 and the edge 12 are integrated by being bonded with an adhesive or the like.

  According to the manufacturing method as described above, since the film 13 of the inorganic compound that does not affect the chemicals is formed on the edge portion 12 made of the flexible material in the vibration plate 10, the sound as the vibration plate 10 is obtained. It is possible to stabilize chemicals while suppressing changes in properties. In particular, in the case of headphones, microphones, and the like, the edge portion 12 protrudes toward the user's ear when worn, so that chemicals are likely to adhere and a high effect is obtained.

  In addition, since the film is formed by inductively coupled plasma CVD capable of normal pressure and low temperature processing, the product properties such as dissolution, swelling, and deformation are changed while suppressing the deterioration and property change of the flexible material of the edge portion 12. No processing can be done.

  The inventor conducted an experiment to examine the resistance and acoustic characteristics of the manufactured diaphragm 10 to chemicals. FIG. 4 is a diagram for explaining the relationship between the thickness of the inorganic compound film and the resistance to chemicals. FIG. 5 is a diagram for explaining the relationship between the thickness of the inorganic compound film and the acoustic characteristics.

  As shown in FIG. 4, the resistance to chemicals increases as the thickness of the inorganic compound film increases, and as shown in FIG. 5, the lowest resonance increases as the thickness of the inorganic compound film increases. The frequency increases. Considering the balance between the thickness at which sufficient resistance to chemicals is obtained and the thickness that does not affect the minimum resonance frequency, the film thickness of the inorganic compound is 25 nm or more so that resistance to chemicals can be obtained. And 400 nm or less with a small raise of the minimum resonance frequency is desirable, More preferably, it is the range of 50 nm-200 nm.

In addition, as a material of the edge portion 12, a thermoplastic polyurethane called TPU (Thermoplastic Polyurethane) having a thickness of 40 μm was measured by measuring the elastic modulus by forming SiO ₂ with a thickness of 300 nm by ICP-CVD method. This treatment increased the modulus of elasticity by about 10%, but had no effect on the product.

  A sunscreen cream (NIVEA SUN (registered trademark) PROTECT WATER GEL SPF30 PA ++) was applied to the treated product as chemicals used in daily life. The untreated product swelled, but the treated product did not swell.

  Therefore, according to the present invention, a speaker diaphragm manufacturing method capable of stabilizing an edge portion formed of a flexible material with respect to chemicals while suppressing changes in acoustic characteristics, and the speaker diaphragm manufacturing method are provided. A speaker diaphragm can be provided.

1 Speaker 2 Yoke 3 Magnet 4 Pole Plate 5 Magnetic Circuit 6 Voice Coil 10 Diaphragm (Speaker Diaphragm)
11 Diaphragm body 12 Edge 13 Inorganic compound film

Claims (6)

  A method for manufacturing a speaker diaphragm, characterized in that an inorganic compound film (13) is formed on the surface of an edge portion (12) formed of a flexible material in the speaker diaphragm (10) by chemical vapor deposition. .   2. The method for manufacturing a speaker diaphragm according to claim 1, wherein the chemical vapor deposition method is an inductively coupled plasma CVD method. The method for manufacturing a speaker diaphragm according to claim 1, wherein the inorganic compound includes any one of SiO ₂ , SiON, and SiN.   The flexible material of the edge portion (12) includes any one of a material obtained by coating rubber on a vulcanized rubber, an elastomer, a woven fabric, or a non-woven fabric base material. Manufacturing method of speaker diaphragm.   5. The loudspeaker diaphragm according to claim 1, wherein a film thickness of the inorganic compound film (13) is 25 nm or more and 400 nm or less, preferably 50 nm to 200 nm. Method.   A speaker diaphragm manufactured by the manufacturing method according to any one of claims 1 to 5.

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