JP7097496B2 - Resin film for speaker diaphragm and laminate for speaker diaphragm - Google Patents

Description

The present invention relates to a speaker diaphragm, a speaker unit, and a resin film for a speaker diaphragm.

In recent years, due to the widening of the band of sound sources, the number of high-resolution sound sources in which signals exceeding 20 kHz of compact discs and 48 kHz or higher are recorded is increasing. Along with this, there is a demand for higher performance of high resonance compatible speakers capable of outputting a high frequency range exceeding 20 kHz, specifically 40 kHz or higher. Regarding high resonance compatible speakers, film speakers (ribbon speakers) tend to be adopted as tweeters or super tweeters in charge of high frequencies because of their wide reproduction band, good phase characteristics, and good transient characteristics. In particular, for high-end model speakers, a Heil-type speaker having a speaker diaphragm folded in a zigzag manner so as to meander is often adopted for the purpose of widening the frequency band and improving the frequency characteristics (Patent Document 1). .. So far, improvement of the structure has been proposed in order to improve the characteristics of these speakers (Patent Document 2).

The diaphragm of a film speaker generally has an organic resin film and a circuit formed of a metal foil on the surface thereof (Patent Document 3). In the case of a model with a large drive current and a film speaker for applications where a high temperature usage environment is expected, a copper-clad polyimide film is used as a diaphragm in order to withstand high temperatures.

Special Publication No. 55-42555 Japanese Unexamined Patent Publication No. 2007-274394 Japanese Unexamined Patent Publication No. 2004-320601

The speaker unit is required to output the sound as it is recorded in the sound source, that is, the original sound reproduction performance. In order to reproduce the original sound, it is desirable that the sound pressure of the speaker unit does not fluctuate depending on the frequency, in other words, the frequency characteristic is flat. In particular, with respect to a speaker compatible with high resonance, a speaker having a flat frequency characteristic up to the high frequency range is desired.

However, the sound pressure of a normal speaker tends to decrease in the high frequency range. Film speakers, especially Heil-type speakers, are relatively good in terms of high-frequency output, but they are not always fully satisfactory.

An object of the present invention is to provide a speaker unit having a small decrease in sound pressure in a high frequency range.

As a result of diligent studies, the present inventors devised the shape of the bellows-shaped diaphragm of the film speaker, and / or by using a diaphragm containing a combination of an organic resin and inorganic particles, in the high frequency range. We have found that a speaker unit with little decrease in sound pressure can be obtained, and completed the present invention.

One aspect of the present invention is a speaker diaphragm having a bellows-shaped film member folded back in a zigzag so that peaks and valleys and side surfaces between them are repeatedly formed along a certain direction. I will provide a. In this speaker diaphragm, the distance between the pair of side surface portions facing each other between the adjacent mountain portions increases from the valley portion side to the mountain portion side.

Another aspect of the present invention provides a resin film for a speaker diaphragm, which comprises a resin film containing an organic resin matrix and inorganic particles dispersed in the organic resin matrix. The above-mentioned bellows-shaped film member can be formed by using this resin film for a speaker diaphragm.

According to the present invention, it is possible to provide a speaker unit having a small decrease in sound pressure in a high frequency range. The speaker diaphragm according to the present invention is also excellent in terms of transient characteristics, efficiency, and audibility as evaluated by humans. Further, the speaker diaphragm according to some embodiments of the present invention can have excellent designability by being colored.

It is an end view which shows one Embodiment of a speaker diaphragm. It is an end view which shows one Embodiment of a speaker diaphragm. It is a top view which shows one Embodiment of a film member. It is a perspective view which shows one Embodiment of a speaker diaphragm. It is an exploded perspective view which shows one Embodiment of a speaker unit. It is a schematic diagram which shows the apparatus for evaluating a speaker unit. It is a graph which shows the example of the frequency characteristic of a general speaker unit. It is a graph which shows the frequency characteristic of the manufactured speaker unit. It is a graph which shows the frequency characteristic of the manufactured speaker unit. It is a graph which shows the frequency characteristic of the manufactured speaker unit. It is a graph which shows the frequency characteristic of the manufactured speaker unit. It is a graph which shows the frequency characteristic of the manufactured speaker unit. It is a waveform diagram of the sound source data for evaluating a transient characteristic. It is a graph which shows the transient characteristic of the manufactured speaker unit. It is a graph which shows the transient characteristic of the manufactured speaker unit. It is a graph which shows the transient characteristic of the manufactured speaker unit. It is a graph which shows the transient characteristic of the manufactured speaker unit. It is a graph which shows the transient characteristic of the manufactured speaker unit. It is an end view which shows an example of the conventional speaker diaphragm.

Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

(Speaker diaphragm)
FIG. 1 is an end view showing an embodiment of a speaker diaphragm. The speaker diaphragm 1 shown in FIG. 1 has a bellows-like shape in which the peak portion 10 and the valley portion 11 and the side surface portion 20 between them are repeatedly formed along a certain direction X in a zigzag manner. It is a film member. The mountain portion 10 and the valley portion 11 are usually curved and extend along the direction Y perpendicular to the direction X, respectively. The constant direction X may coincide with the longitudinal direction of the speaker diaphragm 1.

The pair of side surface portions 20 facing each other between the adjacent mountain portions 10 are connected to each other via the valley portion 11. The pair of side surface portions 20 facing each other are inclined to each other so that the distance is continuously widened from the valley portion 11 side to the mountain portion 10 side. In other words, the distance between the side surface portions 20 at the arbitrary position P ₁ of one side surface portion is W ₁ , and the distance between the side surface portions 20 at the arbitrary position P ₂ on the mountain portion 10 side of the position P ₁ is W ₂ . When, W ₂ is always larger than W ₁ . Here, the distance between the side surface portions at an arbitrary position of one side surface portion means the distance between the arbitrary position of one side surface portion and the other side surface portion in the direction X.

FIG. 19 is an end view showing an example of a conventional speaker diaphragm. In the speaker diaphragm 1 shown in FIG. 19, a pair of planar side surface portions 20 facing each other between adjacent mountain portions 10 are parallel to each other. In the case of a diaphragm having such a shape, the air transmitting the sound generated by the vibration of the side surface portion 20 tends to proceed in the direction of the arrow in the figure (direction toward the adjacent side surface portion), so that the mountain portion 10 It is considered that the proportion of air extruded toward the side is small. On the other hand, in the speaker diaphragm 1 shown in FIG. 1, the air transmitting the sound generated by the vibration of the side surface portion 20 tends to proceed toward the mountain portion 10. Therefore, it is considered that sufficient sound pressure on the mountain portion 10 side can be easily obtained even in the high frequency range. Also, efficiency and transient characteristics can be improved.

In the speaker diaphragm 1 of FIG. 1, the side surface portion 20 includes a flat portion, but the side surface portion 20 may include a curved surface portion. When the side surface portion 20 has a curved surface shape, the boundary between the side surface portion 20 and the curved surface portion 10 or the valley portion 11 may not be clear.

From the viewpoint of frequency characteristics, transient characteristics, etc., the distance between the pair of side surface portions 20 facing each other between the adjacent mountain portions 10 is increased by 1.2 times or more from the valley portion 11 side to the mountain portion 10 side. It may include an inclined planar portion. In other words, the pair of side surface portions 20 may include planar portions that are inclined to each other so that W ₂ / W ₁ becomes 1.2 or more. From the same viewpoint, the planar portions of the pair of side surface portions 20 may be inclined to each other so that W ₂ / W ₁ is 1.5 or more or 2.0 or more. Further, the planar portions of the pair of side surface portions 20 may be inclined to each other so that W ₂ / W ₁ is 4.0 or less, 3.0 or less, or 2.5 or less. Here, the value of W ₂ / W ₁ varies depending on how the position P ₁ and the position P ₂ are selected, but the position P ₁ and the position in the side surface portion 20 so that W ₂ / W ₁ is maximized. The maximum value of W ₂ / W ₁ , that is, W ₂ / W ₁ when P ₂ is selected may be within the above range. Alternatively, the distance between the tip 10a of the mountain portion 10 and the tip 11a of the valley portion 11 in the direction Z (height direction of the mountain portion ₁₀ ) is H, and the position P1 is H × in the direction Z from the tip 11a of the valley portion 11. W ₂ / W ₁ may be within the above range at the position of 1/7, when the position P ₂ is the position of H × 1/7 in the direction Z from the tip 10 a of the mountain portion 10. When the side surface portion 20 includes a planar portion, the position of the boundary between the side surface portion ₂₀ and the curved peak portion ₁₀ or the valley portion 11 is selected as the position P1 and the position P2, and then W ₂ / W ₁ may be within the above range.

When the side surface portions 20 are planar, the pair of side surface portions 20 are a pair of trapezoids having an upper base of length W ₁ and a lower base of length W ₂ and a pair of opposite sides facing each other. It may include a part corresponding to the opposite side of. Regarding the trapezoid at this time, W ₂ / W ₁ may be 1.2 or more, 1.3 or more, 1.4 or more, or 1.5 or more, 4.0 or less, 3.0 or less, or 2 It may be 5.5 or less. The maximum value of W ₂ / W ₁ , that is, W _{2 / W 1 when the position P 1 and the position P 2 in the side surface portion 20 are selected so that W 2 / W 1 becomes the maximum is} within the above range. You may. Alternatively, the distance between the tip 10a of the mountain portion 10 and the tip 11a of the valley portion 11 in the direction Z (height direction of the mountain portion ₁₀ ) is H, and the position P1 is H × in the direction Z from the tip 11a of the valley portion 11. At the position of 1/7, when the position P ₂ is the position of H × 1/7 in the direction Z from the tip 10a of the mountain portion 10, W ₂ / W ₁ in the trapezoid may be within the above range. .. When the side surface portion 20 includes a planar portion, the position of the boundary between the side surface portion ₂₀ and the curved peak portion ₁₀ or the valley portion 11 is selected as the position P1 and the position P2, and at that time, the above W ₂ / W ₁ in the trapezoid may be within the above range.

FIG. 2 is also an end view showing an embodiment of the speaker diaphragm. Also in the speaker diaphragm 1 shown in FIG. 2, the pair of planar side surface portions 20 facing each other between the adjacent mountain portions 10 are continuously widened from the valley portion 11 side to the mountain portion 10 side. Are tilted toward each other. In the speaker diaphragm 1 of FIG. 2, the distance between the pair of side surface portions 20 in the vicinity of the valley portion 11 is relatively large. As a result, even better performance can be achieved in terms of frequency characteristics, transient characteristics, and the like. Specifically, the distance between the side surface portions 20 at an arbitrary position P ₁ of one of the pair of side surface portions 20 is W ₁ , and the side surface portions 20 at the position P ₂ on the mountain side of the arbitrary position 20 are connected to each other. When the distance is W ₂ and the distance between the tip 10a of the mountain portion 10 and the tip 11a of the valley portion 11 in the direction Z (height direction of the mountain portion 10) is H, W ₂ / W ₁ is 1.2 or more. Moreover, the pair of side surface portions 20 may include a planar portion such that W ₁ / H can be 0.4 or more, 0.5 or more, or 0.6 or more. In other words, the pair of side surface portions 20 is a trapezoidal portion having an upper base of length W ₁ and a lower base of length W ₂ and a pair of opposite sides facing each other, corresponding to a pair of opposite sides. It may be included, even if W ₂ / W ₁ is 1.2 or more and W ₁ / H is 0.3 or more, 0.4 or more, 0.5 or more or 0.6 or more in this trapezoid. good. The upper limit of W ₁ / H may be, for example, 1.0 or less. In other words, the position P ₁ and the position P ₂ in which W ₂ / W ₁ and W ₂ / H have values within the numerical range as described above may exist in the side surface portion 20. Alternatively, when the position P ₁ is the position of H × 1/7 in the direction Z from the tip 11a of the valley portion 11, and the position P ₂ is the position of H × 1/7 in the direction Z from the tip 10a of the mountain portion 10. , W ₂ / W ₁ and W ₁ / H may be within the above range. When the side surface portion 20 includes a planar portion, the position of the boundary between the side surface portion ₂₀ and the curved peak portion ₁₀ or the valley portion 11 is selected as the position P1 and the position P2, and then W ₂ / W ₁ and W ₁ / H may be within the above range.

In the speaker diaphragm according to FIGS. 1, 2 or other forms, the distance W0 in the direction X between the tip 10a of the mountain portion 10 and the tip 11a of the valley portion 11 adjacent thereto is the entire speaker diaphragm ₁ . It may be substantially constant over. As a result, the facing side surface portions 20 are formed along the sides of the substantially isosceles trapezoid, and there is a tendency that a good operation balance of the speaker diaphragm is easily maintained. Specifically, the fluctuation range of W ₀ may be an average value of ± 5% or less.

The interval H (height of the mountain portion) may be, for example, 1 to 10 mm. The interval W ₀ may be, for example, 0.5 to 5 mm. The width or length of the film diaphragm may be, for example, 10 to 150 mm.

The speaker diaphragm may be a film member having a resin film (for example, a resin film for a speaker diaphragm described later) and a circuit formed on one side or both sides of the resin film. The circuit may be a conductive film such as a metal leaf. The metal foil is, for example, a copper foil.

(Resin film for speaker diaphragm)
The thickness of the resin film for the speaker diaphragm may be 5 μm or more. When the thickness is 5 μm or more, high mechanical strength and good handleability can be obtained. From the same viewpoint, the thickness of the resin film for the speaker diaphragm may be 10 μm or more. The thickness of the resin film for the speaker diaphragm may be 30 μm or less. When the thickness is 30 μm or less, particularly good transient characteristics can be easily obtained.

When the resin film for the speaker diaphragm is evaluated by the bending resistance test by the cylindrical mandrel method based on JIS-K5600-5-1 (1999), the mandrel diameter at which cracks occur may be 10 mm or less. A resin film having a mandrel diameter of 10 mm or less at which cracking occurs has good flexibility, so that a bellows-shaped speaker diaphragm can be easily manufactured. From the same viewpoint, the mandrel diameter at which the resin film cracks may be 8 mm or less, 5 mm or less, or 4 mm or less.

The resin film for the speaker diaphragm may contain an organic resin matrix and inorganic particles dispersed in the organic resin matrix.

The inorganic particles may be water-insoluble particles. As used herein, "water insoluble" means that the solubility in 100 mL of water at 20 ° C. is less than 1.0 g.

The inorganic particles are at least one inorganic selected from the group consisting of, for example, silicate, silicon oxide, spinnel, aluminum hydroxide, aluminum oxide, aluminum borate, calcium carbonate, nitride, and layered compound hydroxide. It may contain a compound.

The silicate may be a layered silicate. Layered silicates include, for example, natural swelling mica or synthetic swelling mica, natural non-swelling mica or synthetic non-swelling mica, talc, kaolin, pyrophyllite, sericite, vermiculite, smectite, etc. Clay minerals such as bentonite, stepvensite, montmorillonite, byderite, saponite, hectrite, and nontronite can be mentioned. The clay mineral may contain a non-swellable clay mineral because it is easy to produce a uniform resin film for a diaphragm at low cost. The non-swellable clay mineral may be at least one selected from the group consisting of, for example, talc, kaolin, pyrophyllite, natural or synthetic non-swellable mica, and sericite, talc, kaolin, pyro. It may be at least one selected from the group consisting of pyrophyllite and natural non-swelling mica or synthetic non-swelling mica.

The silicate may be an aluminosilicate (silica alumina compound). Examples of the aluminosilicate include zeolite and mullite. The silicate may be waterersanite (calcium silicate).

The silicon oxide may be silica particles containing silicon oxide as a main component, or may be glass beads.

Aluminum compounds such as spinel, aluminum hydroxide, aluminum oxide, and aluminum borate described above can be used in combination with layered silicates. In particular, talc and an aluminum oxide compound may be combined.

Examples of the nitride include silicon nitride and boron nitride.

Examples of the layered double hydroxide include hydrotalcite.

The average particle size of the inorganic particles may be 0.01 μm or more. When the average particle diameter of the inorganic particles is 0.01 μm or more, the resin film for a diaphragm tends to have appropriate mechanical strength. The average particle size of the inorganic particles may be 20 μm or less. When the average particle diameter of the inorganic particles is 20 μm or less, it is easy to obtain a resin film for a diaphragm having high flatness. From the same viewpoint, the average particle size of the inorganic particles may be 0.02 μm or more, 15 μm or less, or 10 μm or less. Here, the average particle size of the inorganic particles can be obtained by measuring the particle size distribution using a laser diffraction type particle size distribution meter or the like.

The content of the inorganic particles in the resin film for the diaphragm may be 5% by mass or more with respect to the total mass of the resin film for the diaphragm. When the content of the inorganic particles is 5% by mass or more, the diaphragm tends to have particularly good frequency characteristics. From the same viewpoint, the content of the inorganic particles may be 10% by mass or more, or 20% by mass or more. The content of the inorganic particles may be 90% by mass or less with respect to the total mass of the resin film for the diaphragm. When the content of the inorganic particles is 90% by mass or less, it is easy to obtain a resin film for a diaphragm having better frequency characteristics. From the same viewpoint, the content of the inorganic particles may be 60% by mass or less, or 40% by mass or less.

The organic resin matrix constituting the resin film for a diaphragm is a continuous phase containing at least one kind of organic resin. Examples of the organic resin include polyimide resin, polyamideimide resin, polyesterimide resin, polyetherimide resin, polybenzoxazole resin, polybenzoimidazole resin, epoxy resin, acrylic resin, polyvinyl fluoride resin, polyurethane resin, and polyester resin. Examples thereof include polyether ether ketone resin, fluororesin, polyether sulfone resin, polyphenylene sulfide resin, polysulfone resin, polyarylate resin, polyether ether ketone resin, or a combination thereof.

The organic resin may be a super engineering plastic. Examples of super engineering plastics include polyimide resins, polyamideimide resins, fluororesins, polyphenylene sulfide resins, polysulfone resins, polyarylate resins, polyethersulfone resins, polyetherimide resins, polyetheretherketone resins, and polybenzoxazole resins. And polybenzoimidazole resins. The organic resin matrix may contain at least one organic resin selected from the group consisting of a polyimide resin, a polyamide-imide resin, and a polybenzoxazole resin because of its excellent heat resistance and mechanical strength. .. From the viewpoint of heat resistance and the like, a polyimide resin may be used as the organic resin.

The polyimide resin is, for example, a polymer having a repeating unit represented by the following formula (1).

In formula (1), R ¹ represents a tetravalent organic group containing one or two benzene rings, and R ² represents a divalent organic group containing one or two benzene rings. R ¹ may be a tetravalent group represented by the following formulas (11), (12), (13), (14), (15) or (16). ^R2 may be a divalent group represented by the following formulas (21), (22), (23), (24), (25), (26), (27) or (28). The polyimide resin may be composed of one type of repeating unit in which R ¹ and R ² are the same, respectively, or may contain two or more types of repeating units in which R ¹ and / or R ² are different from each other.

The polyamide-imide resin is, for example, a polymer having a repeating unit represented by the following formula (2).

In formula (2), R ³ represents a trivalent organic group containing one or two benzene rings, and R ⁴ represents a divalent organic group containing one or two benzene rings. R ³ may be a trivalent group represented by the following formula (31), (32), (33), (34), (35) or (36). ^R4 may be a divalent group represented by the above formulas (21), (22), (23), (24), (25), (26), (27) or (28). The polyamide-imide resin may be composed of one type of repeating unit in which R ³ and R ⁴ are the same, respectively, or may contain two or more types of repeating units in which R ³ and / or R ⁴ are different.

The polybenzoxazole resin is, for example, a polymer having a repeating unit represented by the following formula (3).

In formula (3), R ⁵ represents a tetravalent organic group containing one or two benzene rings, and R ⁶ represents a divalent organic group containing one or two benzene rings. R ⁵ may be a tetravalent group represented by the above formula (11), (12), (13), (14), (15) or (16). R ⁶ may be a divalent group represented by the above formulas (21), (22), (23), (24), (25), (26), (27) or (28). The polybenzoxazole resin may be composed of one repeating unit in which R ⁵ and R ⁶ are the same, respectively, or may contain two or more repeating units in which R ⁵ and / or R ⁶ are different. ..

In formula (1), R ¹ is a tetravalent group represented by the above formula (11) or (12), and R ² is a divalent group represented by the above formula (21), (22) or (23). It may be the basis of. In the formula (2), R ³ is a trivalent group represented by the above formula (31) or (32), and R ⁴ is a divalent group represented by the above formula (21), (22) or (23). It may be the basis of. In formula (3), R ⁵ is a tetravalent group represented by the above formula (11) or (12), and R ⁶ is a divalent group represented by the above formula (21), (22) or (23). It may be the basis of. By using a polyimide resin, a polyamide-imide resin, or a polybenzoxazole resin containing a repeating unit containing these combinations, it is particularly easy to obtain an inexpensive and excellent resin film for a vibration plate.

The resin film for a diaphragm may further contain a pigment for coloring. When the resin film contains a pigment, a speaker unit having excellent design can be obtained. By using the pigment, the diaphragm can be colored in any color such as green, red, blue, yellow, black, and cream.

As the pigment, particles different from the above-mentioned inorganic particles are used. The pigment is not particularly limited, but may be an inorganic pigment. The pigment may be titanium oxide particles colored in a white color or a composite oxide pigment colored in a color other than black. The content of the pigment may be, for example, 20% by mass or less, 10% by mass or less, or 1% by mass or more, based on the total mass of the resin film for the diaphragm.

From the viewpoint of mechanical strength, the resin film for the diaphragm may further contain a coupling agent such as a silane coupling agent and a titanate coupling agent.

Examples of the silane coupling agent include amino-based silane coupling agents, ureido-based silane coupling agents, vinyl-based silane coupling agents, methacrylic-based silane coupling agents, epoxy-based silane coupling agents, and mercapto-based silane coupling agents. , And an isocyanate-based silane coupling agent.

Examples of the titanate coupling agent include a titanate coupling agent having an alkylate group having 1 to 60 carbon atoms, a titanate coupling agent having an alkylphosphite group, a titanate coupling agent having an alkylphosphate group, and an alkylpyrophosphate. Examples thereof include titanate coupling agents having a group.

The content of the coupling agent may be 0.1% by mass or more and 3.0% by mass or less with respect to the mass of the inorganic particles. When the content of the coupling agent is 0.1% by mass or more, the effect of using the coupling agent is easily exhibited sufficiently. Even if the content of the coupling agent exceeds 3.0% by mass, the effect commensurate with the content may not be obtained. From the same viewpoint, the content of the coupling agent may be 0.5% by mass or more and 2.0% by mass or less.

The resin film for the speaker diaphragm may be used to form the resin film of the speaker diaphragm described above. By using the resin film for the speaker diaphragm for the speaker diaphragm described above, the speaker diaphragm can be made more excellent in terms of transient characteristics, efficiency, and audibility according to human evaluation.

(How to manufacture a speaker diaphragm)
The speaker diaphragm includes, for example, a step of folding back a film member having a resin film and a circuit formed on one side or both sides of the resin film in a zigzag manner so as to form desired peaks and valleys. It can be manufactured by the method.

The film member having a circuit is, for example, a step of forming a laminate having a resin film and a conductor film laminated on one side or both sides of the resin film, and removing a part of the conductor film of the laminate. It can be obtained by a method including the step of forming a circuit made of the conductor film.

The laminate having the resin film and the conductor film contains, for example, an organic resin or a precursor thereof, inorganic particles, a solvent for dissolving or dispersing them, and if necessary, other components such as a pigment and a coupling agent. It can be obtained by a method including applying the dispersion to a conductor film (metal foil or the like), removing the solvent from the applied dispersion, and, if necessary, producing the organic resin from the precursor. can. When the organic resin is a polyimide resin, its precursor is, for example, polyamic acid. Inorganic particles may be surface-treated with a coupling agent before preparing the dispersion, or the coupling agent may be added to the dispersion. By including the pigment in the dispersion liquid, a resin film containing the pigment can be easily formed.

After obtaining a laminate having a resin film and a conductor film by a method of applying a dispersion liquid, a conductor film is formed on a surface of the resin film opposite to the conductor film by a method such as a sputtering plating method to form a resin. A laminate in which conductor films are provided on both sides of the film may be obtained. By forming a circuit from this laminated body, it is possible to obtain a film member having circuits formed on both sides. The sputtering plating method can be performed by referring to, for example, Japanese Patent Application Laid-Open No. 2005-019513.

The circuit can be formed by a method of removing a part of the conductor film on the resin film by a method such as etching. For example, a circuit is formed by a method including covering a necessary portion of a conductor film with resist ink and immersing the conductor film in an etching solution in that state to remove an unnecessary portion of the conductor film. Alternatively, a circuit may be formed on the resin film by printing and firing by the method of a printed electronics device.

(Speaker unit)
The speaker unit according to the embodiment includes the speaker diaphragm according to the above-described embodiment. This speaker unit may be a film speaker such as a Heil type speaker. The speaker unit may further include other members normally used in the speaker, such as magnets provided around the speaker diaphragm, terminals for connecting to an external device, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

1. 1. Laminated body having a resin film for a speaker diaphragm (Production Example 1)
Production of polyamic acid In a 1 L four-necked flask equipped with a stirrer and a thermometer, 73.2 g of 4,4'-diaminodiphenyl ether and 832 g of N-methyl-2-pyrrolidone were placed, and the internal temperature was stirred while stirring. Was heated to 50 ° C. to dissolve the 4,4'-diaminodiphenyl ether. Next, 40 g of pyromellitic anhydride and 51 g of biphenyltetracarboxylic acid dianhydride were gradually added. After completion of the addition, the reaction solution was stirred for 1 hour to obtain a polyamic acid solution containing N-methyl-2-pyrrolidone at a concentration of 16.5% by mass of the aromatic polyamic acid represented by the following formula (I). ..

Preparation of dispersion for resin film formation 22.5 g of the obtained polyamic acid solution and 2.5 g of talc (manufactured by Nippon Tarku Co., Ltd., "D600" average particle size 0.6 μm) are placed in a plastic airtight container, and a rotating and revolving mixer. ("ARE-310" manufactured by Shinky Co., Ltd.) was used for stirring. The conditions for stirring were set in the order of stirring in the mixing mode (2000 rpm) for 10 minutes and in the defoaming mode (2200 rpm) for 10 minutes. As a result, the ratio of talc to the total non-volatile component (component other than solvent or total amount of polyamic acid and talc) is 40.2% by mass, and the non-volatile component (component other than solvent, polyamic acid) to the total amount of the dispersion liquid A uniform resin film-forming dispersion having a proportion of talc (total amount of talc) of 24.9% by mass was obtained.

Preparation of Resin Film for Speaker Diaphragm The obtained dispersion liquid for forming a resin film was applied to a copper foil having a thickness of 9 μm so as to have a thickness of 80 μm using a doctor blade. The coating film was dried for 10 hours while heating at 50 ° C. in a forced ventilation oven with the copper foil kept horizontal to form a film on the copper foil. The film was heated at 120 ° C. for 30 minutes, 150 ° C. for 5 minutes, 200 ° C. for 5 minutes, and 350 ° C. for 30 minutes to contain talc and polyimide resin, with a ratio of talc to total mass of 40. A brown resin film (thickness 20 μm) having a thickness of .2% by mass was formed on the copper foil to obtain a laminate composed of the resin film for the speaker vibrating plate and the copper foil.

(Production Example 2)
2. Similar to Example 1 except that 9 g and Asahi Kasei Kagaku Kogyo Co., Ltd. composite oxide pigment Green No. 2024 0.6 g were used, the ratio of the inorganic particles to the total non-volatile components was 40.2% by mass and dispersed. A uniform resin film forming dispersion was obtained in which the ratio of the total non-volatile components to the total mass of the liquid was 24.9% by mass.

Preparation of Resin Film for Speaker Diaphragm A laminate consisting of a green resin film for speaker diaphragm with a thickness of 20 μm and a copper foil with a thickness of 9 μm was prepared in the same manner as in Production Example 1 except that the obtained dispersion was used. Made. The resin film was composed of talc, a green pigment and a polyimide resin, and the ratio of the inorganic particles to the total mass of the resin film was 40.2% by mass.

(Production Example 3)
Preparation of Resin Film for Speaker Diaphragm A laminate consisting of a resin film for speaker diaphragm and a copper foil with a thickness of 9 μm was produced in the same manner as in Production Example 1 except that the thickness of the resin film was changed to 15 μm. Next, a copper foil with a thickness of 9 μm was formed on the surface of the prepared laminate on the resin film side by a sputtering plating method, and a laminate having a structure in which the copper foil with a thickness of 9 μm was provided on both sides of the resin film was created. did.

(Comparison laminate)
A double-sided copper-clad polyimide film composed of a polyimide film (thickness 12.5 μm) containing no inorganic particles and copper foil (thickness 9 μm) on both sides thereof was prepared as a laminate for comparison.

2. 2. Speaker diaphragm and speaker unit (1) Preparation of speaker diaphragm A resist ink was applied to the copper foil of each prepared laminate by the silk printing method. Next, the unnecessary copper foil is removed by immersing it in an etching solution kept at 40 ° C. for 3 minutes, and the resin film is cut into a required size to form a resin film for a speaker diaphragm as shown in FIG. 3 and a flat film member 1A having a circuit 5 formed of a copper foil were obtained.

The obtained film member was folded back in a zigzag manner using a jig to form peaks and valleys arranged at substantially equal intervals. At this time, the film member was folded back while inclining the facing side surface portions so as to widen the distance between the facing side surface portions from the valley portion side to the mountain portion side. After that, the film member was fixed with a one-component elastic adhesive so that the folded shape could be maintained. As a result, a speaker diaphragm made of a bellows-shaped film member as shown in FIG. 4 was obtained. Further, using the comparative laminate, a speaker diaphragm folded in a zigzag manner so that the facing side surfaces are parallel to each other was produced.

(2) Speaker unit Using each of the manufactured speaker diaphragms, speaker units 1 to 5 having the configuration of the speaker unit 100 shown in FIG. 5 were assembled. Table 1 shows the configuration of the diaphragm used for each speaker unit.

First, the speaker diaphragm 1 was attached to the holder 31 and fixed with a one-component elastic adhesive. After attaching the neodymium magnet 37 to the rear panel 39, the speaker case 41, the spacers 33, 35, the holder 31 to which the speaker diaphragm 1 was attached, and the front panel 43 were attached to the rear panel 39. Further, a terminal for connecting to an external device such as an amplifier and a lead wire from the speaker diaphragm were connected to obtain speaker units 1 to 5 for evaluation.

3. 3. Evaluation of Frequency Characteristics FIG. 6 is a schematic diagram of a device for measuring the frequency characteristics of the speaker unit. In FIG. 6, a speaker 200 equipped with a speaker unit for evaluation is connected to a power amplifier 53 (DC-100 kHz), and the power amplifier 53 is connected to a computer 51 via a D / A converter 52. A microphone 54 is installed at a position at a distance D from the speaker 200 (speaker unit), and a computer 57 is connected to the microphone 54 via an A / D converter 55 with a built-in microphone amplifier. The distance D is 1 m. A UA-1010 manufactured by Roland was used as the D / A converter 52 and the A / D converter 55 with a built-in microphone amplifier. As the microphone 54, CO-100K manufactured by Sanken was used.

Using the device of FIG. 6, the frequency characteristics of each speaker unit were measured in an anechoic chamber by the following procedure.
(1) The frequency data to be measured is transmitted from the computer 51.
(2) The transmitted data is converted into an analog signal by a D / A converter, and a sound corresponding to the frequency of the transmitted data is output from the speaker 200 through the power amplifier 53 (output: 1W).
(3) The output sound is collected by the microphone 54.
(4) The collected sound is converted into digital data by the A / D converter 55 and then sent to the computer 57.
(5) The data input to the computer 57 is processed by the measurement software to obtain a graph showing the relationship between the output and the frequency.

FIG. 7 is a graph showing the frequency characteristics (relationship between output and frequency) of a general speaker unit. The higher the sound pressure of the output, the higher the efficiency as a speaker. Ideally, the sound pressure does not drop depending on the frequency and is constant in the entire frequency range.

8 is a graph showing the frequency characteristics of the speaker unit 1, FIG. 9 is the speaker unit 2, FIG. 10 is the speaker unit 3, FIG. 11 is the speaker unit 4, and FIG. 12 is the speaker unit 5. FIGS. 8 to 12 show a frequency range of 0 kHz to 48 kHz.

From the comparison between the speaker units 1 to 4 (FIGS. 8 to 11) and the speaker unit 5 (FIG. 12) in the frequency range of 0 kHz to 48 kHz, by using a diaphragm whose facing side surfaces are inclined, the facing side surfaces are used. It can be confirmed that a high sound pressure is maintained up to a high frequency range and a flat frequency characteristic can be obtained, as compared with the case of using a diaphragm having parallel parts. Further, from the comparison between the speaker units 1 to 3 (FIGS. 8 to 10) and the speaker unit 4 (FIG. 11), a diaphragm formed by using a resin film containing inorganic particles and having an inclined side surface portion facing the speaker unit is formed. By using it, it can be confirmed that a more remarkable effect can be obtained in terms of flat frequency characteristics.

4. Evaluation of Transient Characteristics Using the device shown in FIG. 6, the transient characteristics of each speaker unit were evaluated by the following procedure.
(1) The computer 51 transmits sound source data for a specific time at a specific frequency once.
(2) The transmitted data is converted into an analog signal by the D / A converter 52, and the sound of the frequency and time corresponding to the data is output from the speaker 200 through the power amplifier 53. The voltage applied to the speaker was set to 1W.
(3) The output sound is collected by the microphone 54.
(4) The collected sound is converted into digital data by the A / D converter 55 and then sent to the computer 57.
(5) The data input to the computer 57 is processed by the measurement software, and a graph showing the relationship between the output and the time is obtained.

FIG. 13 shows a waveform of sound source data sent from the computer 51. The sound source data is a short-time rectangular wave data, and this data is transmitted only once. “0” on the time axis is the time of the starting point at which the sound source data is transmitted. 14 is a graph showing the measurement results of the transient characteristics of the speaker unit 1, FIG. 15 is the speaker unit 2, FIG. 16 is the speaker unit 3, FIG. 17 is the speaker unit 4, and FIG. 18 is the speaker unit 5. In each figure, the horizontal axis is time, the vertical axis is the input level, and the sound collected by the microphone is waveformized. Since the distance D between the speaker unit and the microphone is 1 m, the starting point of the observed waveform is observed with a delay of about 2.88 ms from the starting point of the sound source data.

Ideally, a sound having the same waveform as the waveform of the sound source data is output, but since the electrical signal is converted into a physical phenomenon, the output is not the same as the waveform of the sound source data. The waveform at the rising edge of the output is not a rectangle of the sound source data but an ellipse due to a slight time delay and level loss. At the falling portion of the output, the contraction of the diaphragm does not return to the original position instantly, but returns to the original position while repeating contraction and expansion several times, so that a plurality of aftermaths are generated. The sound output from the speaker having excellent transient characteristics shows a rising portion close to the waveform of the sound source data and a falling portion where the number of aftermaths is small and the sound converges in a short time.

From the comparison between the speaker units 1, 2 and 3 (FIGS. 14, 15 and 16) and the speaker units 4 and 5 (FIGS. 17 and 18), they are formed by using a resin film containing inorganic particles, and the facing side surfaces are inclined. By using a diaphragm that is used, an output that shows a rising part that is closer to the waveform of the sound source data and a falling part that converges in a short time with less aftermath than using a diaphragm with parallel side surfaces. Can be confirmed to be obtained.

4. Hearing sensation evaluation Among the devices of FIG. 6, the audibility was evaluated by a human monitor using the computer 51, the D / A converter 52, the power amplifier 53, and the speaker 200. As the speaker 200, a speaker unit for evaluation was attached as a tweeter, and the woofer and squawker were fixed to the same speaker. Hearing was evaluated by the following procedure.
(1) High resolution compatible sound source data is transmitted from the computer 51, restored to an analog signal by the D / A converter 52, and the music amplified by the power amplifier 53 is reproduced from the speaker 200.
(2) Vocal music, symphony, piano music, violin music, jazz, and movie music were used as sound source data. Monitors of 20 men and women in their 20s to 60s audition the reproduced sound, and the hearing of speakers equipped with speaker units 1, 3, 4, and a commercially available cone tweeter is relative, with the case of speaker unit 5 as the standard. Evaluated to. Regarding each item shown in Table 2, the monitor determined that the item inferior to the standard was C, the item similar to the standard was B, and the item superior was A.

From the comparison between the speaker units 1, 3 and 4 and the speaker unit 5, using a diaphragm with inclined side surfaces gives a better hearing than using a diaphragm with parallel side surfaces. It can be confirmed that it can be obtained. Furthermore, from the comparison between the speaker units 1 and 3 and the speaker unit 4, it can be confirmed that even more excellent audibility can be obtained by using the resin film containing the inorganic particles.

1 ... speaker diaphragm (bellows-shaped film member), 1A ... flat film member, 3 ... speaker diaphragm resin film, 5 ... circuit, 10 ... mountain part, 10a ... mountain part tip, 11 ... valley part , 11a ... Tani part tip, 20 ... Side part, 31 ... Holder, 33, 35 ... Spacer, 37 ... Neodymium magnet, 39 ... Rear panel, 41 ... Speaker case, 43 ... Front panel, W ₀ ... Yamabe tip Spacing between the tip of the valley, W ₁ ... Spacing between the side surfaces at position P ₁ , W ₂ ... Spacing between the side surfaces at position P ₂ , H ... Spacing between the tip of the mountain and the tip of the valley, 100 … Speaker unit.

Claims (6)

It contains an organic resin matrix and inorganic particles dispersed in the organic resin matrix.
The inorganic particles contain layered silicate and
The organic resin matrix contains at least one resin selected from the group consisting of a polyimide resin, a polyamide-imide resin, and a polybenzoxazole resin.
A resin film for a speaker diaphragm having a thickness of 5 μm or more and 30 μm or less.
The content of the inorganic particles in the resin film for the speaker diaphragm is 40% by mass or more and 60% by mass or less with respect to the total mass of the resin film for the diaphragm.
Speaker vibration having a bellows-shaped film member folded back in a zigzag manner so that the resin film for a speaker diaphragm is repeatedly formed in a certain direction in a mountain portion and a valley portion and a side surface portion between them. It is used as the film member of the plate.
The distance between the pair of side surface portions facing each other between the adjacent mountain portions is continuously widened from the valley side to the mountain portion side.
Resin film for speaker diaphragm. The resin film for a speaker diaphragm according to claim 1, wherein the resin film is colored. Claim 1 in which the mandrel diameter at which cracks occur is 10 mm or less when the resin film for a speaker diaphragm is evaluated by a bending resistance test by a cylindrical mandrel method based on JIS-K5600-5-1 (1999). Or the resin film for the speaker diaphragm according to 2. The resin film for a speaker diaphragm according to any one of claims 1 to 3, wherein the distance between the tips of the adjacent peaks and valleys is substantially constant. The pair of side surface portions facing each other between the adjacent mountain portions are inclined to each other so that the distance in the certain direction is increased by 1.2 times or more from the valley portion side to the mountain portion side. The resin film for a speaker diaphragm according to any one of claims 1 to 4, which includes a flat portion. A laminated body for a speaker diaphragm, comprising the resin film for a speaker diaphragm according to any one of claims 1 to 5 and a conductor film provided on one side or both sides of the resin film.

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