JPH0773399B2 - Vibration plate for audio equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a diaphragm for an audio device, and more particularly to a diaphragm using a metal material. This kind of thing, for example,
It is used as a diaphragm for converters such as speakers.

BACKGROUND OF THE INVENTION When a metallic material is used as a diaphragm, various measures are taken to improve its acoustic characteristics. That is, a metal material generally has a high resonance sharpness (that is, a low internal loss), so that a sharp peak is generated in the vicinity of fh (a wide-range limit frequency), and a peculiar coloration causes an unpleasant sound. There are some difficulties. The difficulty is
It is possible to solve the problem to some extent by using a vibration-damping metal material itself (a vibration-damping alloy such as Al-Zn, Mg-Zr, or Ti-Ni) or by combining a metal material and a vibration-proof material. For example, aluminum base material can be solved to some extent by applying anti-vibration rubber or resin (synthetic rubber, natural rubber, foamed urethane or other elastomers), etc., or by laminating it to create a vibration-damping structure. Is. This vibration damping structure is generally performed not only with respect to the anti-vibration effect, but also with consideration of durability (in particular, improvement of corrosion resistance of metal by coating and laminating) and appearance. Examples include resin coating of urethane, epoxy, acrylic, etc. on the surface of the material, and laminating with an elastic film such as olefin, amide, or ionomer. However, if the vibration damping material is increased for the purpose of enhancing the vibration damping effect, the processing thickness increases in proportion to it, and the weight increases, leading to a decrease in sensitivity, which is a problem.

On the other hand, the metal material used as the diaphragm is required to have improved durability and high strength, and in particular, it is desired to improve the specific elastic modulus (higher sound velocity). However, such improvement in mechanical strength and increase in elasticity are generally in a contradictory relationship with the above-described reduction in resonance, and it is difficult to achieve both at the same time. In addition, the increase in the density of the material to increase the strength and the increase in the total weight lead to a decrease in sensitivity. In addition, as conventional strength and elasticity techniques, metal boride, carbide, nitride, oxide, etc. are deposited on the surface of the material by means of CVD, PVD (sputtering, plasma spraying, ion beam), etc. Alternatively, thermal spraying of ceramics may be mentioned, but these require a large-scale device, are technically advanced, and cannot be easily applied. In addition, it may be possible to form a composite by taking a clad structure by laminating with a dissimilar metal, or to alloy to achieve strength improvement, but with the relationship with the problem of vibration damping described above,
Furthermore, considering the problems of weight increase, productivity, processability, and other points, it is not always satisfactory.

Aluminum has been used as a conventional metal material for the diaphragm, for example, which has moderate acoustic physical properties and should be satisfied in terms of processability, durability, productivity, and cost, but the internal loss is small ( The problem is that the resonance sharpness is high) and the strength is insufficient, which limits its practical use. Therefore, it is disadvantageous when it is desired to extend fh to a higher position or when it is desired to suppress the peak in the high frequency range and flatten the band sensitivity.

From these, in order to use aluminum as a metal material, it is strongly desired to reduce the resonance and increase the strength. In addition, the situation is the same when magnesium or titanium is used.

As described above, in order to solve the above-mentioned problems of the metal material, various methods for improving the composite have been adopted. For example, a typical method is used to form a honeycomb diaphragm. In this method, the reproduction band range is determined by D / σ (D is the bending rigidity and σ is the surface density). However, since the bending rigidity D is increased in the honeycomb structure, the reproduction band range can be expanded. However, in order to further expand this range, it is necessary to further increase the bending rigidity D. Moreover, it is desirable to further reduce the surface density σ depending on the material used as the surface material. For this purpose, it is necessary to make the surface material lighter and stronger. Furthermore, in order to suppress the generation of sharp peaks (high resonance sharpness) of higher-order modes in the honeycomb diaphragm, it is necessary to improve the internal loss of the surface material, that is, to lower the resonance as described above. is there. Also, in terms of contributing to high sensitivity, it is desirable to reduce the density.

These circumstances are the same in vibration systems other than the honeycomb vibration plate, and it is desired to reduce the resonance, increase the rigidity, and decrease the density of the metal material used as the vibration plate.

On the other hand, a technique has been proposed in which aluminum is anodized and the pores of the alumina layer are filled with nickel or molten aluminum to improve the acoustic characteristics (Japanese Patent Publication Nos. 57-13198 and 57-11553). However, these techniques have a weak diffusion force of the filler into the pores, have a problem of adhesion, and are unstable. In the case of nickel filling, the density increases,
It is a disadvantage. It has also been proposed to form a large number of small holes in a metal substrate such as aluminum, and to fill the small holes with a substance having a large internal loss such as synthetic resin or oil (Japanese Patent Publication No. 55-55).
-15156) also has a problem with stability, and it is difficult to apply it to a material having fine pores such as an anodized film. In addition, there is a problem of deterioration of the filled synthetic resin and oil. Moreover, the density becomes large.

In addition, an alumina layer is formed on the aluminum substrate by anodizing treatment, and inside the pores of this alumina layer
A speaker diaphragm has been proposed which is filled with a filler made of Ni, Cr, Fe and synthetic resin (Japanese Patent Laid-Open No. 54-97).
015), but this also has the same drawbacks as the above-mentioned conventional techniques.

[Object of the Invention] The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the resonance sharpness (that is, increase the internal loss) of a metal material used and increase the bending rigidity. It is possible to prevent the occurrence of peaks in the high frequency range, expand the playback band range, and modify the eigen sound, and increase the density without increasing the density, reducing the sensitivity, and reducing the sensitivity evenly. Moreover, it is an object of the present invention to provide an advantageous diaphragm for audio equipment, which can be easily realized at low cost.

[Structure of the Invention] A diaphragm for an audio device of the present invention is a diaphragm for an audio device using a metal material in which an anodized film is formed on both surfaces of a foil-shaped metal material, and is formed on both surfaces of the metal material. A diaphragm for an audio device, wherein a phosphorus compound is produced in at least a part of the fine pores of the anodized film thus formed.

In the present invention, the metal material used for the diaphragm is anodizable, and examples of such metal include aluminum, magnesium, titanium and other valve metals. When the present invention is carried out, the metallic material can be used in the form of foil.

In the present invention, the phosphorus compound is generated in at least a part of the fine pores formed in the oxide film of the anodized metal material. As the phosphorus compound, phosphorus oxide,
Examples thereof include compounds of phosphorus with a metal. In order to generate the phosphorus oxide in the fine pores in the anodic oxide film, for example, the secondary electrolysis method can be used. In the case of the secondary electrolysis method, a metal material having an oxide film formed by primary anodic oxidation is used as an anode, and a solution containing various phosphoric acid salts is used as an electrolytic solution for secondary electrolysis. Give. Then, various phosphate ions, which are negative ions in the electrolytic solution, are attracted to the surface of the metal material, and mainly various phosphate radicals are discharged in the active fine pores of the oxide film to generate in the form of phosphorus oxide. Therefore, phosphorus oxide is impregnated in the fine pores. Various types of phosphorus oxides can be produced depending on the type of the phosphoric acid compound used and the treatment conditions, but any of them can be adopted.

Further, in order to generate the intermetallic compound of phosphorus in the fine pores, for example, the electroless plating method can be used. In this case, using a metal electroless plating solution containing phosphorus,
Thereby, the metal material provided with the anodized film is plated.
Then, the deposited metal plating is in the form of a metal compound containing phosphorus, which is formed in the fine pores of the anodic oxide film.

In addition, a lead compound may be filled in the micropores or the micropores may be sealed with a phosphorus compound by using an appropriate means.

[Advantageous Effects of the Invention] According to the present invention, the rigidity of a diaphragm can be improved by forming anodic oxide films on both surfaces of a metal material, and the anodic oxide film can be made to contain phosphorus compounds in fine pores. It is possible to solve the problem that the internal loss of the anodic oxide film alone is small and Q increases due to the generation of. That is, according to the present invention, the phosphorus compound generated in the fine pores of the anodic oxide film promotes the ferroelasticity / resonance of the metal material, thereby improving the resonance sharpness (internal loss) of the metal material in a high range. It is possible to prevent the occurrence of peaks and expand the band range, and to improve the eigentone.

Originally, the acoustic physical characteristics of phosphorus alone are as shown in Table 1,
It has a property of slightly less than twice that of aluminum. However, as is well known, phosphorus alone is extremely unstable, is difficult to handle by itself, and cannot be deposited alone on a metal material.
It is considered impossible to apply phosphorus to this kind of acoustic material, and it has been neglected in the past.

However, the present invention makes it possible to obtain good results by using the phosphorus compound in combination with the metal material in the above-mentioned constitution.

Moreover, the present invention does not cause variations such as vapor deposition or ion beam due to the direction of the gun, a uniform structure is obtained, the sensitivity is not lowered, and the weight is not particularly changed. Moreover, such an effect can be achieved by a simple technique and can be obtained at low cost.

The diaphragm obtained by the present invention is used for various purposes, for example, in the shape of a flat plate, a circle, a dome, etc., and can be used for various speakers, and there is no particular limitation as to the use of the diaphragm.

[Examples of the Invention] Some of the examples of the present invention will be described below. However, as a matter of course, the present invention is not limited to the following examples.

Example 1 In this example, aluminum was used as the metal material. In particular, foil-shaped aluminum was used, and it was used as a skin material of a honeycomb structure. Further, in this example, phosphorus oxide was generated in the fine pores of the oxide film, and this was generated by the secondary electrolysis method.

Hereinafter, this embodiment will be described.

In this example, first, aluminum foil (several μ to several tens of μ
(Thickness) is anodized to form an anodized film on it. The conditions for this anodic oxidation are 15 wt% sulfuric acid and 25 ° C.
It was processed by flowing a direct current of 1 A to dm ² for 18 minutes. The anodic oxide film thus obtained is α-mono-hydrate (A
l ₂ O ₃ · H ₂ O) film, the film thickness is about 6μ on each side, and the diameter of the fine holes is about 200Å.

Aluminum with an anodic oxide film as described above,
It is treated by the secondary electrolysis method and impregnated with phosphorus oxide.

That is, using an aluminum phosphate aqueous solution of 0.1 wt%, the aluminum with the above anodic oxide film as the anode,
A secondary current of 50 mA / dm ² was applied for 5 minutes for secondary electrolysis. Since ammonium phosphate ionizes in an aqueous solution as shown in the formula below, its phosphate ions (PO ₄ ³⁻ ) are attracted to the aluminum, which is the anode, and as a result, phosphorus oxide, which is a phosphorus compound, is contained in the micropores. Is generated.

(NH ₄ ) ₃ PO ₄ → PO ₄ ^{3 −} + 3NH ₄ ⁺ Under these conditions, the film thickness of the oxide film (anodic oxide film) impregnated with the phosphorus compound is about 3 to 4 μm. The object appears to be PO ₄ as is.

The cross section of the material obtained by this example is considered as shown in FIG. That is, an anodic oxide film (alumite layer) 2 is formed on both sides of aluminum 1, and a part of this oxide film 2 is a part (phosphorus oxide-containing oxide film layer) 3 in which phosphorus oxide is contained in the fine pores. It is estimated that Overall thickness t
Of about 23 μ, and the thickness t ′ of the oxide film 2 therein is about 6 μ each.

Table 2 shows the physical properties of the diaphragm prototyped using the obtained sample. For comparison, the physical properties of aluminum and alumina are shown.

As is clear from the above table, in the case of this example, the ferroelasticity and low resonance were promoted with respect to aluminum, and the peak in the high range was suppressed and the band could be extended. In terms of sound quality,
It was possible to remove the coloration inherent to aluminum. That is, the sample of this example has a remarkably lower resonance sharpness than aluminum and alumina, and therefore, the problem of internal loss of aluminum and the anodized film can be solved, and the occurrence of peaks in the high range can be suppressed. Further, the elastic modulus is slightly larger than that of aluminum, and as a result, the bending rigidity becomes high and the limit frequency can be made high, so that the reproduction band range, particularly in the high range, can be widened. Since the data of alumina show the alumina itself, the elastic modulus is higher, but it is considered that the portion that contributes to the anodized aluminum is small. The sample of this example has almost the same density as aluminum and almost no change in weight. The density is slightly small, and is expected to contribute to the improvement of sensitivity.

As described above, in the present embodiment, a well-balanced diaphragm which could not be obtained by using aluminum alone or an anodized film was obtained, and the sound quality was good with no harsh coloration.

In addition, phosphorus compounds can be generated in the micropores by using various phosphoric acid compounds and under the appropriate conditions in the same manner as above.

Example 2 In this example, an electroless plating method was used to generate an intermetallic compound of phosphorus in the micropores.

Using aluminum that had been subjected to primary anodization in the same manner as in Example 1, this was subjected to Ni-P electroless plating. Ni
As the -P electroless plating solution, for example, Blue Sumer (trade name) manufactured by Kanigen Co., Ltd. is used, and the solution temperature is 90 to 95 ° C.
For 10 minutes. Usually, the content of phosphorus contained in these electroless plating solutions is around 10%. By such a treatment, a nickel compound of phosphorus is generated in the fine pores of the aluminum oxide film. In the case of this example, the obtained plating thickness was 4 to 5 μm. The characteristics of the diaphragm using the sample obtained in this example are as shown in Table 3.

Also in the case of this example, the internal loss is large and the resonance sharpness can be remarkably reduced. The elastic modulus is about the same as that of aluminum, which is slightly inferior to that of Example 1, but it can be sufficiently put to practical use.

Other than electroless plating of nickel, any metal that can be electroless plated can be applied by incorporating phosphorus.

[Advantages of the Invention] As described above, in the diaphragm for an audio device of the present invention, the resonance sharpness is lowered (that is, the internal loss is increased) and the bending rigidity is increased, so that the occurrence of a peak in a high range is prevented. Prevention, expansion of the reproduction band range, modification of eigen sound are possible, and these are uniform without decreasing sensitivity, and weight is not particularly increased or decreased,
Moreover, there is an effect that it can be easily realized at low cost.

Of course, the present invention is not limited to the above-mentioned embodiments.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention. 1 ... Metal material (aluminum), 2 ... Anodic oxide film,
3 ... Phosphorus oxide-containing oxide film layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Samukawa, Inventor Hiroyuki Samukawa, 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Nobuo Tomiya, 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Masakazu Maejima 1-5-1 Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. (72) Inventor Koichi Saruwatari 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Den Line Co., Ltd. (56) Reference JP-A-54-97015 (JP, A) JP-A-59-140398 (JP, A) JP-B-55-47119 (JP, B2)

Claims (1)

[Claims] 1. A diaphragm for an audio device, which uses a metal material in which an anodized film is formed on both sides of a foil-shaped metal material, wherein the anodized film has fine pores formed in both sides of the metal material. A diaphragm for an audio device, characterized in that a phosphorus compound is produced at least in part.