JPH1188982A - Drive system component for electroacoustic transducer and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive system component of an electroacoustic transducer where a thin diaphragm whose partial thickness is controlled and a voice coil are integrated with a simple method. SOLUTION: A diaphragm consisting of a moving part 1a and a stationary part 1b is formed by coating or printing a solvent soluble heat-resistant resin solution, a voice coil is formed directly on the moving part 1a, the thickness of the moving part 1a is selected to be 2-40 μm and the thickness of the stationary part 1b is selected thicker than the thickness of the moving part 1a, and the voice coil and the diaphragm are integrated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive system component in which a new diaphragm and a voice coil of an electroacoustic transducer are integrated.

[0002]

2. Description of the Related Art In order to improve the performance of an electroacoustic transducer, it is important to reduce the mass of a driving system as much as possible. Therefore, even for a speaker of a film surface drive type, such as a so-called flat speaker, which is considered to be advantageous for weight reduction, further weight reduction has been achieved. But,
Conventionally, the voice coil (conductor circuit) separately prepared on a plastic film has been bonded to the film surface drive type speaker with an adhesive.
Various problems arising from the production method could not be avoided.

That is, by using an adhesive, the mass of the vibration system is increased and the electroacoustic conversion efficiency is reduced, and the adhesive has the lowest heat resistance in terms of heat resistance against heat generated by a drive current. There was a problem that the allowable input power (power handling) was limited as a bottleneck.

[0004] Therefore, a method that does not use an adhesive having such a problem has been studied, and the method is directly applied to a plastic film.
Methods of depositing metal and coating resin have also been proposed, but there are limitations on the thickness of existing plastic films as a base material, and selection of materials based on the thickness of metal foil and resin coating and acoustic characteristics There are also various restrictions, and no satisfactory one has been realized. In addition, when a flexible printed circuit board (FPC) type voice coil as described above is generally used, the leads of the input and output lead terminals are connected to the same plane as the acoustic radiation surface or the incident surface. There is also a problem that the protection of the wire is naturally required, which reduces the acoustic characteristics and the effective intersection with the magnetic circuit, thereby lowering the overall conversion efficiency.

[0005] In addition, a diaphragm voice coil using a material for general FPC has a structure in which a conductive foil of a circuit pattern is exposed, so that electroacoustic characteristics are deteriorated due to metal corrosion and reliability is low. There is a problem that becomes. On the other hand, in the case of a normal electric circuit, a countermeasure using an overlay can be considered.
Is high, and it is difficult to adopt it because it causes abnormal noise.
Further, if the coating is performed in the same manner as a normal electronic circuit in order to secure the concealing property, the increase in mass cannot be ignored, and it will not be practically used.

On the other hand, if the thickness of the heat-resistant resin film of the diaphragm is reduced to less than 10 μm in order to improve the electro-acoustic conversion efficiency, the workability of bonding to the peripheral frame is deteriorated, and furthermore, However, it is originally difficult to obtain such a thin commercially available heat-resistant resin film.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and is thinner than the conventional one and can partially control the thickness. It is an object to provide an integrated diaphragm (diaphragm).

[0008]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventor has focused on the base material of the voice coil, and as a result of repeated studies, it has been found that a polyimide resin which is a heat-resistant resin and has solvent solubility is obtained. The present inventors have found that the resin has the required characteristics, and solved the problem at once by printing and applying a solution of the resin, thereby completing the present invention. That is, the present invention is a diaphragm having a movable part and a fixed part, which is formed by applying or printing a solvent-soluble heat-resistant resin solution, and a voice coil is directly formed on the movable part having a thickness of 2 to 40 μm. The present invention provides a drive system component of an electroacoustic transducer in which a voice coil and a diaphragm are integrated with each other, wherein the thickness of the fixed portion is at least thicker than the movable portion.

The present invention also provides a process for producing a substrate of a diaphragm having a thickness of 2 to 20 μm by applying or printing a solvent-soluble heat-resistant resin solution, a process of laminating a metal foil on a movable portion of the substrate, Forming a voice coil pattern by a subtractive method, applying a cover coat of a predetermined pattern on the voice coil pattern using the same resin solution as described above, and applying the same resin solution to a fixed portion of the substrate. And / or a step of applying or printing a resin solution to which a filler is added in a predetermined pattern, and a step of solder welding a lead wire to an exposed portion of the metal foil of the obtained diaphragm. An object of the present invention is to provide a method for manufacturing a drive system component of an electroacoustic transducer in which a diaphragm is integrated.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An object of the present invention is a drive system component of an electroacoustic transducer, specifically, a drive system component having a diaphragm (diaphragm), a voice coil, and a lead portion of a lead wire thereof. Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of an external magnet type film surface drive speaker showing an example of an electrodynamic electroacoustic transducer incorporating a drive system component of the present invention. FIG. 2 is a schematic cross-sectional view of another example of an inner-magnet-type film surface drive speaker. The drive system components of the present invention are used for the drive system that forms the main part of the speakers of FIGS. 1 and 2, but the shape is not limited to the circular shape shown in FIG. A magnetic circuit (voice coil) having a shape provided with a magnetic gap can also be used.

FIG. 3 is a plan view of a diaphragm pattern for a circular magnetic circuit showing an example of a drive system component of the present invention. In FIG. 3, reference numeral 1a denotes a movable portion of the diaphragm, on which a conductor pattern is formed and a voice coil is integrated. Reference numeral 1b denotes a fixed portion of the diaphragm, which is thicker than the movable portion of 1a. In addition, it is also a preferable embodiment to apply a resin solution containing an additive for increasing rigidity such as a filler to the resin in the portion while increasing the thickness. 1
The fixed portion b is provided with a solder connection portion (6a) for a lead wire. Therefore, the resin in the portion 1b must have at least heat resistance enough to withstand soldering.

FIG. 4 is a schematic sectional view showing a sectional structure of the diaphragm and a mode of lead wire drawing. As shown in FIG. 4, a voice coil is disposed on the movable portion of the diaphragm, and this portion (1a) can be made thinner to the limit where pinholes occur in the resin film to reduce the weight. desirable.

On the other hand, the fixed part (1b) of the diaphragm is
In terms of strength, it is necessary to have an appropriate thickness in order to facilitate work and handling during assembly. Since lands are formed at the same position on the front and back of the fixed portion as shown in FIG. 4, solder welding of the lead wire can be performed from either side, and the degree of freedom of design is increased, and quality is improved. It also contributes to improvement.

It is particularly important to select a resin constituting the drive system components including the diaphragm and the voice coil of the present invention.
The resin must be one that can be easily printed and applied, and has solder heat resistance, good adhesion to conductor patterns, moderate flexibility, and sufficient strength even when thin. Must have the requirement to have As the resin satisfying such requirements, a specific resin can be selected from polyimide resins and used. For example, a solvent-soluble polyimide-based resin is preferable, and a solvent-soluble aromatic polyamideimide resin is particularly preferable.

The solvent-soluble polyamideimide resin suitable for the present invention is obtained by reacting an aromatic diamine with trimellitic anhydride chloride in an organic polar solvent or by reacting an aromatic diisocyanate and trimellitic anhydride in an organic polar solvent. The reaction can be carried out in the following manner. or,
SOXR (registered trademark) commercially available from Nippon Kogyo Paper Industries Co., Ltd. is the most excellent aromatic polyamideimide resin among the above-mentioned suitable aromatic polyamideimide resins.

Furthermore, fillers such as beryllia (BeO), magnesia (MgO), boron nitride (BN), alumina (Al ₂ O ₃ ), silicon carbide (SiC), and silicon nitride (Si ₃ N) are added to the above resin. ₄ ), mica and those containing 1-3% by volume of a mixture thereof are suitably used for a diaphragm fixing portion.

As the aromatic diamine used in the above resin, 4,4′-diaminodiphenyl ether,
Preferred are 4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, and 4,4'-diaminodiphenylmethane. Of these, 4,4'-diaminodiphenyl ether is particularly preferred.

Examples of the organic solvent for the aromatic polyamideimide resin include N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, hexamethylphosphoramide, cresol halide, Or a mixed solvent of these with other conventional solvents. Of these, N-dimethylacetamide and N
-Methyl-2-pyrrolidone is preferred.

As the conductor metal constituting the voice coil, a metal foil such as aluminum, copper, nickel or the like is used.
Among them, aluminum foil is a preferred metal body in terms of lightness, economy and workability.

The drive system component of the present invention in which the voice coil and the diaphragm are integrated can be manufactured by using a known flexible printed wiring board manufacturing technology. That is, first, an aromatic polyamideimide solution is applied to a target diaphragm shape by a known method such as a screen printing method or a blade coaster method, and then dried and heated to manufacture a diaphragm substrate. Next, a metal foil of a predetermined shape is laminated on the movable portion of the diaphragm substrate, a desired coil pattern is formed on the metal foil using a pattern resist, and after etching, the resist is peeled off. A voice coil is formed by an active method.

Necessary portions such as a voice coil and a fixing portion are overcoated by screen printing or the like using the previously used solution of the aromatic polyamide-imide resin or the like. After that, a solder coat, a flux coat, a plating, or the like is applied to the exposed lead wire solder joints. In addition, the movable part where the voice coil is provided should be as thin as possible within the limit of the required strength, and the fixed part provided outside it should be thickened or hardened using the resin containing filler described above. Is essential.

The drive system component of the present invention is used as a drive system component for an electro-acoustic transducer, for example, a speaker, an earphone, a microphone, etc., as described above, but may also be used as a diaphragm for an electromagnetic transducer or a sensor. Available.

[0023]

【Example】

Example 1 A solution obtained by dissolving a solvent-soluble aromatic polyamideimide resin (manufactured by Nippon Advanced Paper Industry Co., Ltd., registered trademark: Soxeal) in an N-methyl-2-pyrrolidone solution was screen-printed, and then heated and dried, and then dried. A circular diaphragm substrate having a thickness of 7 μm and a diameter of 5 cm in a dry state is prepared. A disk of aluminum foil having a diameter of 4 cm and a thickness of 20 μm was placed at the center of the substrate, and was heated at 180 ° C. for 20 minutes for 30 minutes using a hot press.
It was hot-pressed at kg / cm ² and laminated. On the aluminum foil, a pattern of an annular voice coil (coil DC resistance value: 6Ω) having an outer diameter of 4 cm and an inner diameter of 1 cm shown in FIG. 3 was screen-printed using a commercially available dry film etching resist, and exposed in a conventional manner. A developing step is performed to form a resist pattern for the voice coil.

Then, etching is performed using a commercially available etching solution for aluminum foil, and the resist is stripped by treating with a commercially available stripping solution. After heating and drying the obtained diaphragm substrate having the voice coil, a predetermined pattern having an opening such as a lead wire connection portion is screen-printed using the above-mentioned aromatic polyamideimide solution to form an overcoat layer having a thickness of 7 μm. Is provided.

Further, 10% by volume of boron nitride is added to the fixed part (diameter 0.95 cm) at the center of the diaphragm and the fixed part (outer diameter 5 cm, inner diameter 4.1 cm) at the periphery of the diaphragm shown in FIG. A solution of an aromatic polyamideimide (registered trademark: Soksil, manufactured by Nippon Advanced Paper Industry Co., Ltd.)
Screen-print to a thickness of 5 nm and heat dry. When the exposed wiring portion (6a in FIG. 3) is plated and the lead wires are connected by solder, a diaphragm with a voice coil shown in FIGS. 3 and 4 is obtained.

[0026]

The drive system component of the electroacoustic transducer according to the present invention can be formed such that an arbitrary portion of the diaphragm has a thick peripheral portion by printing or coating, and the movable portion is formed as a thin film of 2 to 40 μm. As a result, the electroacoustic conversion efficiency and the frequency response characteristics are good, and the structural strength of the diaphragm frame is also improved, so that the handling and assembling work is easy and the quality is uniform. Also, resin coating can be easily applied to both surfaces of the voice coil by printing or coating, peeling and breakage of the voice coil can be prevented, electric short-circuit can be improved, and the resin coating of the conductor foil can be achieved. Surface corrosion is also prevented, and there is an effect that environmental resistance and reliability during long-term use can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of an external-magnet type film surface drive speaker incorporating a drive system component of an electroacoustic transducer of the present invention.

FIG. 2 is a schematic cross-sectional view showing one embodiment of an inner-magnet type film surface drive speaker incorporating a drive system component of the electroacoustic transducer of the present invention.

FIG. 3 is a plan view of a circular diaphragm with a voice coil showing one embodiment of a drive system component of the present invention.

FIG. 4 is a partial sectional view of the diaphragm shown in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diaphragm 1a Voice coil part (diaphragm movable part) 1b Diaphragm fixed part 2 Yoke 2a Frame integrated yoke 3 Plate 3a Hole piece 4 Magnet 5 Frame 5a Frame equalizer part 5b Frame short horn part 6 Lead wire 6a Lead wire solder connection Part 7 Terminal

Claims (5)

[Claims] 1. A diaphragm having a movable portion and a fixed portion formed by applying or printing a solvent-soluble heat-resistant resin solution, wherein a voice coil is directly formed on the movable portion having a thickness of 2 to 40 μm. A drive system component of an electroacoustic transducer in which a voice coil and a diaphragm are integrated, wherein a thickness of the fixed portion is thicker than at least the movable portion. 2. The drive component according to claim 1, wherein the solvent-soluble heat-resistant resin solution applied or printed on the fixing portion is a solvent-soluble heat-resistant resin solution containing a filler. 3. The drive system component according to claim 1, wherein the solvent-soluble heat-resistant resin is a solvent-soluble aromatic polyamideimide resin. 4. A step of manufacturing a substrate of a diaphragm having a thickness of 2 to 20 μm by applying or printing a solvent-soluble heat-resistant resin solution, a step of laminating a metal foil on a movable portion of the substrate, and a step of subtracting the metal foil. Forming a voice coil pattern by a method, applying a cover coat of a predetermined pattern on the voice coil pattern using the same resin solution as described above, and applying the same resin solution and / or to a fixed portion of the substrate. A step of applying or printing a resin solution to which a filler is added in a predetermined pattern, and a step of solder-welding a lead wire to an exposed portion of the metal foil of the obtained diaphragm. A method of manufacturing a drive system component of an integrated electroacoustic transducer. 5. The method according to claim 4, wherein the solvent-soluble heat-resistant resin is a solvent-soluble aromatic polyamideimide resin, and the metal foil is an aluminum foil.