JP2004088297A - Diaphragm for speaker and speaker employing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diaphragm applied, in particular, to small-sized speakers that can satisfy requirements of a low minimum resonance frequency f0, a proper thickness, a low elastic rate, and a high internal loss. <P>SOLUTION: The diaphragm adopts a double layer structure wherein an elastomer layer 31 is provided to front and rear sides or one side of a base member 30. Thus, the diaphragm 27 for speakers satisfying the requirements of the low minimum resonance frequency f0, the low elastic rate, and the high internal loss is configured. <P>COPYRIGHT: (C)2004,JPO

Description

【００６６】
（表１）より、実施例１および実施例２は比較例１に比べて、低ｆ０化、低歪化が実現できていることがわかる。
【００６７】
これらのスピーカ用振動板は、その材質や材厚は、形状安定性やコストの点で望ましく、マイクロスピーカに要求される内部損失、材厚、重量を満足させることができる。
【００６８】
前記の構成とすることで、携帯電話に代表されるマイクロスピーカや一般のスピーカに要求される性能を満足できるスピーカを提供することができる。
【００６９】
【発明の効果】
以上のように本発明は、樹脂製基材の表、裏面または片面にエラストマー層を設けて複層構造を有するスピーカ用振動板を構成したものである。さらに、このスピーカ用振動板を使用してスピーカを構成している。
【００７０】
これらの構成とすることで、スピーカ用振動板の形状安定性向上やコスト低減化を図ることができる。また内部損失、材厚、重量、剛性を最適化して周波数特性の良好化を実現することができる。さらに、接着性等の信頼性向上や外観品位の向上を図ることができるスピーカを提供することができる。
【００７１】
よって、携帯電話に代表されるマイクロスピーカや一般のスピーカに要求される性能を満足できる優れたスピーカを提供することができ、その工業的価値は非常に大なるものである。
【図面の簡単な説明】
【図１】本発明の一実施の形態におけるスピーカ用振動板の断面図
【図２】本発明の他の実施の形態におけるスピーカ用振動板の断面図
【図３】本発明の他の実施の形態におけるスピーカ用振動板の断面図
【図４】本発明の他の実施の形態におけるスピーカ用振動板の断面図
【図５】本発明の他の実施の形態におけるスピーカ用振動板の断面図
【図６】本発明の一実施の形態におけるスピーカの断面図
【図７】従来のスピーカ用振動板の断面図
【符号の説明】
２１　マグネット
２２　上部プレート
２３　ヨーク
２４　磁気回路
２５　磁気ギャップ
２６　フレーム
２７　スピーカ用振動板
２７Ａ　スピーカ用振動板
２７Ｂ　スピーカ用振動板
２７Ｃ　スピーカ用振動板
２７Ｄ　スピーカ用振動板
２７ｄ　スピーカ用振動板の一部
２８　ボイスコイル
３０　基材
３０Ａ　基材
３０Ｂ　基材
３１　エラストマー層
３１Ａ　エラストマー層
３１Ｂ　エラストマー層
３１Ｃ　エラストマー層
３１Ｄ　エラストマー層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a speaker diaphragm and a speaker using the same.
[0002]
[Prior art]
As a diaphragm used for a micro speaker for a mobile phone, a sheet made of polyethylene or the like was formed by heat press molding to form a diaphragm 7 having a shape shown in FIG. The diaphragm 7 is used to constitute a micro speaker.
[0003]
The same configuration as described above was applied to a general speaker, particularly to a tweeter or the like.
[0004]
Here, the physical properties required for the diaphragm 7 are determined by the balance between the square root of the sound speed: E (Young's modulus) / ρ (specific gravity) and the internal loss, and the sound quality is improved and the f0 is reduced (f0: lowest). (Resonance frequency).
[0005]
Conventionally, polyethylene naphthalate (PEN), polyetherimide (PEI), or the like is used as the diaphragm. Japanese Patent Application Laid-Open No. H11-266493 discloses a method of laminating a metal thin plate on a resin film. However, this method makes it possible to improve the sound quality but makes it difficult to reduce f0. Also, Japanese Patent Application Laid-Open No. 03-57400 proposes a sandwich structure for high elastic modulus and high internal loss.
[0006]
[Problems to be solved by the invention]
Since the PEN has a large Young's modulus of 6000 MPa, in a speaker for a mobile phone that requires a low minimum resonance frequency (f0), the diaphragm thickness must be extremely thin in order to reduce f0. Therefore, in PEN having high crystallinity, variation in dimensional accuracy becomes large, and the variation leads to variation in various characteristics of the speaker. Therefore, there is a problem that the dimensional accuracy and various characteristics become unstable due to being too thin.
[0007]
PEI has a Young's modulus of 2800 MPa, which is more flexible than PEN, and can secure a thickness that maintains dimensional accuracy even if f0 is designed to be small. However, the internal loss (tan δ) is about 0.02 near room temperature (PEN is about 0.04), and rolling and the like are likely to occur, resulting in a large distortion and deterioration in sound quality.
[0008]
Therefore, an object of the present invention is to provide a diaphragm that can satisfy the requirement of low f0, appropriate material thickness, low elastic modulus, and high internal loss, particularly in a small speaker.
[0009]
[Means for Solving the Problems]
An object of the present invention is to provide a speaker diaphragm that has high sound quality and supports low f0.
[0010]
That is, the present invention has the following configurations.
[0011]
The invention according to claim 1 of the present invention is configured such that a speaker diaphragm is formed by providing an elastomer layer on a surface of a base material made of a resin having a Young's modulus of 2500 MPa or more and an internal loss of 0.03 or less. It is. With this configuration, it is possible to realize a speaker diaphragm that can satisfy both a low elastic modulus and a high internal loss.
[0012]
The invention according to claim 2 of the present invention is configured such that a speaker diaphragm is provided by providing an elastomer layer on a surface of a base material made of a resin having a Young's modulus of 2500 MPa or more and an internal loss of 0.02 or less. is there. With this configuration, it is possible to realize a speaker diaphragm that can satisfy a low elastic modulus and a high internal loss by using a base material having a small internal loss.
[0013]
According to a third aspect of the present invention, a speaker diaphragm is formed by providing an elastomer layer on the front and back surfaces of a resin base material. With this configuration, it is possible to realize a diaphragm that can satisfy a further lower elastic modulus and a higher internal loss with an effect over both surfaces of the base material.
[0014]
According to a fourth aspect of the present invention, there is provided a speaker diaphragm according to the first to third aspects, wherein the base material is formed by press forming or vacuum forming. With this configuration, the productivity of the speaker diaphragm can be improved.
[0015]
According to a fifth aspect of the present invention, there is provided a speaker diaphragm according to the first to fourth aspects, wherein the base material is polyetherimide (PEI). With this configuration, the reliability of the speaker diaphragm can be improved.
[0016]
According to a sixth aspect of the present invention, there is provided a speaker diaphragm according to the first to fifth aspects, wherein the elastomer layer is a crosslinked elastomer. With this configuration, it is possible to improve the mold releasability of the speaker diaphragm.
[0017]
According to a seventh aspect of the present invention, there is provided a speaker diaphragm according to the sixth aspect, wherein the crosslinked elastomer is a urethane-based elastomer. With this configuration, the cost of the speaker diaphragm can be reduced.
[0018]
The invention according to claim 8 of the present invention is the speaker diaphragm according to claim 6, wherein the crosslinked elastomer is a silicone-based elastomer. With this configuration, the heat resistance and temperature characteristics of the speaker diaphragm can be stabilized.
[0019]
According to a ninth aspect of the present invention, there is provided a speaker diaphragm according to the sixth aspect, wherein the crosslinked elastomer is a hydrocarbon-based elastomer. With this configuration, the internal loss of the speaker diaphragm can be increased.
[0020]
According to a tenth aspect of the present invention, there is provided a speaker diaphragm according to the sixth aspect, wherein the crosslinked elastomer is a fluoroelastomer. With this configuration, the mold releasability and heat resistance of the speaker diaphragm can be particularly improved.
[0021]
According to an eleventh aspect of the present invention, the speaker diaphragm according to the third aspect is constituted by two or more kinds of crosslinked elastomers according to the seventh to tenth aspects. With this configuration, it is possible to freely set a low elastic modulus and a high internal loss of the diaphragm.
[0022]
The twelfth aspect of the present invention is the speaker diaphragm according to the first to eleventh aspects, wherein at least one elastomer layer is provided on at least two substrates to form a multilayer structure. With this configuration, it is possible to further reduce the elastic modulus and the internal loss of the speaker diaphragm, and to set the values freely.
[0023]
According to a thirteenth aspect of the present invention, the speaker diaphragm according to the first to twelfth aspects is configured such that the thickness of the base material is varied depending on the location when the base material is formed. With this configuration, a low elastic modulus and a high internal loss at a specific position of the speaker diaphragm can be achieved, and unnecessary resonance of the speaker diaphragm can be controlled.
[0024]
According to a fourteenth aspect of the present invention, there is provided one or more loudspeakers according to the first to thirteenth aspects, wherein a part or the whole of the one loudspeaker diaphragm according to the first to thirteenth aspects. The diaphragm for speaker is constructed by joining a part of the diaphragm for speaker. With this configuration, it is possible to achieve a low elastic modulus and a high internal loss at a specific position, and it is possible to control unnecessary resonance.
[0025]
According to a fifteenth aspect of the present invention, a loudspeaker is configured using any one of the loudspeaker diaphragms according to the first to fourteenth aspects. With this configuration, by improving the elastic modulus and the internal loss of the diaphragm, it is possible to improve the sound quality and characteristics of the speaker, expand the low-frequency reproduction band, and reduce unnecessary resonance.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0027]
The diaphragm used in the present invention has a multilayer structure in which an elastomer layer is provided on the front, back, or one surface of a resin base material.
[0028]
(Embodiment 1)
Hereinafter, the first and second aspects of the present invention will be described in detail with reference to the first embodiment.
[0029]
FIG. 1 is a sectional view of a speaker diaphragm 27 according to an embodiment of the present invention. That is, in the first aspect of the present invention, the speaker diaphragm 27 is formed by providing the elastomer layer 31 on the surface of the base material 30 made of resin. Here, the substrate 30 made of this resin is formed of a resin having a Young's modulus of 2500 MPa or more and an internal loss of 0.03 or less. With this configuration, it is possible to realize the speaker diaphragm 27 that can satisfy a low elastic modulus and a high internal loss.
[0030]
As described above, the resin of the base material 30 can be used as long as the material has a Young's modulus of 2500 MPa or more and an internal loss of 0.03 or less. Many resins generally called engineering plastics, such as PEI and aromatic polyimide, may be mentioned. PEI having a relatively low Young's modulus and a small internal loss is preferable because the internal loss of the elastomer layer 31 is increased.
[0031]
The invention described in claim 2 uses the base material 30 of FIG. 1 made of a resin having a Young's modulus of 2500 MPa or more and an internal loss of 0.02 or less. With this configuration, it is possible to realize a speaker diaphragm 27 that can satisfy a low elastic modulus and a high internal loss by using the base material 30 having a smaller internal loss than the first aspect.
[0032]
Further, according to the invention as set forth in claim 4, the diaphragm 27 is formed into a required shape as shown in FIG. 1, specifically, a disk-shaped one is processed into a circular shape at a portion A in FIG. The state is different. That is, the diaphragm can be formed into a required shape by a method such as press molding or vacuum molding using a metal mold, and the diaphragm 30 has good productivity.
[0033]
Next, according to a fifth aspect of the present invention, the substrate 30 is made of polyetherimide (PEI). According to this configuration, since the polyetherimide (PEI) as the base material 30 has an effect as a highly reliable physical property, it is possible to realize an improvement in reliability such as a countermeasure against crack generation of the diaphragm.
[0034]
Next, the details of the elastomer layer 31 will be described.
[0035]
According to a sixth aspect of the present invention, the elastomer layer 31 is a crosslinked elastomer. With this configuration, the mold releasability of the speaker diaphragm 27 can be improved. It is also preferable in that the adhesiveness to the mold during the secondary molding (at the time of molding into the shape of the speaker diaphragm 27) is small.
[0036]
In the invention according to claim 7 of the present invention, the crosslinked elastomer is a urethane-based elastomer. With this configuration, the cost of the speaker diaphragm 27 can be reduced. For this reason, if a crosslinkable elastomer having a too small molecular weight between crosslink points is used, it cannot be formed into a dome shape as shown in FIG. 1, for example. For this purpose, hydrolysis-condensation type (moisture-cured) urethanes having a relatively large molecular weight between cross-linking points, hydrolysis-condensation type silicones, addition-reaction type silicones, peroxide-cured silicones, and hydrolysis-condensation type hydrocarbon-based elastomers (For example, isobutylene-based or isoprene-based) is more preferable.
[0037]
The invention according to claim 8 is that the crosslinked elastomer is a silicone elastomer. With this configuration, heat resistance and temperature characteristics of the speaker diaphragm 27 can be stabilized.
[0038]
The invention according to claim 9 of the present invention is that the crosslinked elastomer is a hydrocarbon elastomer. With this configuration, the internal loss of the speaker diaphragm 27 can be increased.
[0039]
The invention described in claim 10 of the present invention is that the crosslinked elastomer is a fluoroelastomer. With this configuration, the mold releasability and heat resistance of the speaker diaphragm 27 can be particularly improved.
[0040]
Among these, the most preferable combination is a combination of PEI and a hydrolysis-condensation type urethane in consideration of cost, expansion of internal loss, and reduction of adhesiveness during molding. Further, although the cost is high, PEI and silicone (regardless of the cured form) are preferable from the viewpoint of heat resistance.
[0041]
(Embodiment 2)
Hereinafter, the second embodiment of the present invention will be described, in particular, the third and eleventh aspects of the present invention.
[0042]
FIG. 2 is a cross-sectional view of speaker diaphragm 27A in the present embodiment. According to a third aspect of the present invention, as shown in FIG. 2, a speaker diaphragm 27A is provided by providing elastomer layers 31A and 31B on both front and back surfaces of a base material 30. With this configuration, it is possible to realize a speaker diaphragm 27A that can satisfy a further lower elastic modulus and a higher internal loss by an effect over both surfaces of the diaphragm.
[0043]
According to an eleventh aspect of the present invention, there is provided a speaker diaphragm 27A according to the third aspect, wherein the crosslinked elastomer is two or more kinds of the elastomers according to the seventh to tenth aspects. With this configuration, it is possible to freely set a low elastic modulus and a high internal loss of the speaker diaphragm 27A.
[0044]
(Embodiment 3)
Hereinafter, the third embodiment of the present invention will be described with reference to the third embodiment.
[0045]
FIG. 3 is a cross-sectional view of speaker diaphragm 27B in the present embodiment. The twelfth aspect of the present invention provides a speaker diaphragm having a multi-layer structure in which two or more resin base materials 30A and 30B are provided with one or more elastomer layers 31C and 31D as shown in FIG. 27B. With this configuration, it is possible to further reduce the elastic modulus and increase the internal loss of the speaker diaphragm 27B, and to set the values freely.
[0046]
(Embodiment 4)
Hereinafter, a fourth embodiment of the present invention will be described with reference to the fourth embodiment.
[0047]
FIG. 4 is a sectional view of a speaker diaphragm 27C according to an embodiment of the present invention. According to a thirteenth aspect of the present invention, the material thickness of the diaphragm 27C at the time of forming the diaphragm 27C is variable depending on the location. Specifically, the center portion is thick and the outer periphery is thin. With this configuration, a low elastic modulus (thin wall) and a high internal loss (thick wall) at a specific position of the speaker diaphragm 27C can be achieved, and unnecessary resonance thereof can be controlled.
[0048]
(Embodiment 5)
Hereinafter, a fifth embodiment of the present invention will be described with reference to a fifth embodiment.
[0049]
FIG. 5 is a cross-sectional view of speaker diaphragm 27D according to the present embodiment. According to a fourteenth aspect of the present invention, there is provided a speaker diaphragm according to any one of the first to thirteenth aspects (for example, 27 in FIG. 1). A part (ring shape) 27d of two speaker diaphragms (for example, 27 in FIG. 1) is joined to form a speaker diaphragm 27D. With this configuration, it is possible to reduce the elastic modulus (the outer periphery of the portion A) and increase the internal loss (the inner periphery of the portion A) at a specific position of the diaphragm 27D, and it is possible to control the unnecessary resonance.
[0050]
(Embodiment 6)
Hereinafter, a sixth embodiment of the present invention will be described with reference to FIG.
[0051]
FIG. 6 is a sectional view of a speaker according to an embodiment of the present invention. According to a fifteenth aspect of the present invention, a loudspeaker is configured using any one of the loudspeaker diaphragms 27, 27A to 27D according to the first to fourteenth aspects.
[0052]
In FIG. 6, the magnetized magnet 21 is sandwiched between the upper plate 22 and the yoke 23 to form an inner-magnet type magnetic circuit 24. The frame 26 is connected to the yoke 23 of the magnetic circuit 24. Any one of the speaker diaphragms 27 according to any one of claims 1 to 14 is bonded to the inner peripheral edge of the frame 26.
[0053]
A cylindrical voice coil 28 is connected to the lower surface of the portion A of the speaker diaphragm 27, and the voice coil 28 is connected so as to fit into the magnetic gap 25 of the magnetic circuit 24.
[0054]
That is, by reducing the elastic modulus and the internal loss of the speaker diaphragm 27, it is possible to improve the sound quality and characteristics of the speaker, expand the low-frequency reproduction band, and reduce unnecessary resonance.
[0055]
Next, the material thickness of the speaker diaphragm 27 used in the present invention will be described.
[0056]
Since the speaker diaphragm 27 used in the present invention is used for a small speaker, it is 100 μm or less, preferably 50 μm or less, and most preferably 30 μm or less. If the thickness is too small, problems such as dimensional accuracy occur.
[0057]
The thickness balance between the resin base material 30 and the elastomer layer 31 is such that if the thickness of the resin base material 30 is not 50% or more, the diaphragm thickness becomes unnecessarily thick when sound pressure is generated as a speaker. Would. However, when the base material 30 accounts for 95% or more of the whole, the effect of the elastomer layer 31 becomes difficult to obtain. Preferably, the thickness of the resin substrate 30 is 60% to 90% of the whole.
[0058]
The dome-shaped speaker diaphragm 27 made of the material of the present invention in a dome shape as shown in FIG. 1 has a large internal loss, prevents rolling, and is a speaker diaphragm capable of achieving high sound quality and low f0.
[0059]
【Example】
An embodiment of the present invention will be described below.
[0060]
(Example 1)
A 1.5 μm addition-reaction silicone (elastomer layer 31), a speaker diaphragm having a Young's modulus of 2800 MPa, an internal loss of 0.019, and a 6 μm PEI (base material 30) sandwiched on the front and back sides (see FIG. 2) shape).
The internal loss of the composite diaphragm of Example 1 was 0.040.
[0061]
(Example 2)
A two-layer loudspeaker diaphragm of 3 μm hydrolysis-condensation type (moisture curing type) urethane (elastomer layer 31) and a 6 μm PEI (base material 30) having a Young's modulus of 2800 MPa and an internal loss of 0.019 (FIG. 1) Shape).
The internal loss of the speaker diaphragm of Example 2 was 0.034.
[0062]
(Comparative Example 1)
One PEI (base material 30) diaphragm having a Young's modulus of 2800 MPa and an internal loss of 0.019 and a thickness of 7 μm.
[0063]
From the above configuration, it can be seen that the internal loss of Example 1 and Example 2 can be larger than that of Comparative Example 1.
[0064]
F0 and distortion are summarized below.
[0065]
[Table 1]

[0066]
Table 1 shows that Examples 1 and 2 can achieve lower f0 and lower distortion than Comparative Example 1.
[0067]
The material and material thickness of these speaker diaphragms are desirable in terms of shape stability and cost, and can satisfy the internal loss, material thickness, and weight required for a micro speaker.
[0068]
With the above structure, it is possible to provide a speaker capable of satisfying the performance required of a micro speaker represented by a mobile phone or a general speaker.
[0069]
【The invention's effect】
As described above, the present invention provides a speaker diaphragm having a multilayer structure by providing an elastomer layer on the front, back, or one surface of a resin base material. Further, a speaker is configured using the speaker diaphragm.
[0070]
With such a configuration, it is possible to improve the shape stability and reduce the cost of the speaker diaphragm. In addition, the internal loss, the material thickness, the weight, and the rigidity are optimized, and the frequency characteristics can be improved. Further, it is possible to provide a speaker capable of improving reliability such as adhesiveness and improving appearance quality.
[0071]
Therefore, it is possible to provide an excellent speaker capable of satisfying the performance required of a micro speaker represented by a mobile phone or a general speaker, and its industrial value is extremely large.
[Brief description of the drawings]
FIG. 1 is a sectional view of a speaker diaphragm in one embodiment of the present invention; FIG. 2 is a sectional view of a speaker diaphragm in another embodiment of the present invention; FIG. 3 is another embodiment of the present invention; FIG. 4 is a sectional view of a speaker diaphragm according to another embodiment of the present invention. FIG. 5 is a sectional view of a speaker diaphragm according to another embodiment of the present invention. FIG. 6 is a cross-sectional view of a speaker according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of a conventional speaker diaphragm.
Reference Signs List 21 magnet 22 upper plate 23 yoke 24 magnetic circuit 25 magnetic gap 26 frame 27 speaker diaphragm 27A speaker diaphragm 27B speaker diaphragm 27C speaker diaphragm 27D speaker diaphragm 27d part of speaker diaphragm 28 voice Coil 30 Base 30A Base 30B Base 31 Elastomer layer 31A Elastomer layer 31B Elastomer layer 31C Elastomer layer 31D Elastomer layer

Claims (15)

A diaphragm for a speaker, comprising a resin base material having a Young's modulus of 2500 MPa or more and an internal loss of 0.03 or less, provided with an elastomer layer on a surface thereof. The speaker diaphragm according to claim 1, wherein a resin base material having an internal loss of 0.02 or less is used. The speaker diaphragm according to claim 1 or 2, wherein an elastomer layer is provided on the front and back surfaces of the resin base material. The speaker diaphragm according to any one of claims 1 to 3, wherein the substrate is formed by press molding or vacuum molding. The speaker diaphragm according to any one of claims 1 to 4, wherein the base material is polyetherimide (PEI). The speaker diaphragm according to any one of claims 1 to 5, wherein the elastomer layer is a crosslinked elastomer. 7. The speaker diaphragm according to claim 6, wherein the crosslinked elastomer is a urethane-based elastomer. 7. The speaker diaphragm according to claim 6, wherein the crosslinked elastomer is a silicone elastomer. 7. The speaker diaphragm according to claim 6, wherein the crosslinked elastomer is a hydrocarbon elastomer. 7. The diaphragm for a speaker according to claim 6, wherein the crosslinked elastomer is a fluoroelastomer. The speaker diaphragm according to claim 3, wherein the elastomer layer is formed of two or more kinds of the crosslinked elastomers according to any one of claims 7 to 10. The speaker diaphragm according to any one of claims 1 to 11, wherein the diaphragm is a multilayer structure including two or more resin base materials and one or more elastomer layers. 5. The diaphragm for a speaker according to claim 4, wherein the thickness of the base material is varied depending on the location when the base material is formed. A speaker diaphragm in which one or more of the speaker diaphragm substrates according to any one of claims 1 to 13 is joined to a part or all of the speaker diaphragm according to any one of claims 1 to 13. . A speaker using the speaker diaphragm according to any one of claims 1 to 14.

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