JP4123030B2 - Speaker diaphragm and speaker using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a speaker diaphragm and a speaker using the same.
[0002]
[Prior art]
The diaphragm used for the microspeaker for the cellular phone is formed as a diaphragm 7 by heat-pressing a sheet of polyethylene or the like into the shape shown in FIG. A speaker is configured using the diaphragm 7.
[0003]
In general, when applied to a speaker, particularly a tweeter, the same configuration as described above is used.
[0004]
Here, the physical properties required for the diaphragm 7 are directed by the balance between the square root of the sound velocity: E (Young's modulus) / ρ (specific gravity) and the internal loss, so that the sound quality is improved and f0 is reduced (f0: lowest). (Resonance frequency).
[0005]
Conventionally, polyethylene naphthalate (PEN), polyetherimide (PEI), or the like is used as the diaphragm material.
[0006]
As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 63-218349
[Problems to be solved by the invention]
Since PEN has a large Young's modulus of 6000 MPa, a cellular phone speaker that is required to have a low minimum resonance frequency (F0) needs to be extremely thin in order to reduce F0. However, PEN with high crystallinity has a large variation in dimensional accuracy, and there is a problem that dimensional accuracy and various characteristics become unstable when the thickness is reduced.
[0009]
PEI has a Young's modulus of 2800 MPa, which is more flexible than PEN, and even if F0 is designed to be small, a thickness that maintains dimensional accuracy can be secured. 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, distortion is increased, and the sound quality is deteriorated.
[0010]
Accordingly, an object of the present invention is to provide a diaphragm capable of achieving high sound quality and low F0, particularly in a small speaker.
[0011]
[Means for Solving the Problems]
The present invention has the following configuration in order to provide a diaphragm material that has high sound quality and supports low F0.
[0012]
According to the first aspect of the present invention, an elastomer layer is provided on a resin substrate having a Young's modulus of 2500 MPa or more, an internal loss of 0.03 or less , and a thickness of 60% to 90% of the whole. The loudspeaker diaphragm is formed by pressure forming the material thus formed into a required shape. With this configuration, it is possible to provide a diaphragm with high sound quality and low F0.
[0013]
According to the second aspect of the present invention, an elastomer layer is provided on both surfaces of a resin base material. With this configuration, it is possible to realize a diaphragm that can satisfy both a low elastic modulus and a high internal loss due to the effects on both sides of the diaphragm.
[0014]
In the invention according to claim 3 of the present invention, the resin base material is polyetherimide (PEI). With this configuration, it is possible to improve the reliability of the diaphragm while making it suitable for molding.
[0015]
According to a fourth aspect of the present invention, the elastomer layer is a cross-linked elastomer. With this configuration, the mold releasability of the diaphragm can be improved.
[0016]
In the invention according to claim 5 of the present invention, the cross-linked elastomer is a urethane-based elastomer. With this configuration, the cost of the diaphragm can be reduced.
[0017]
The invention according to claim 6 of the present invention is a silicone elastomer as the cross-linkable elastomer. With this configuration, the heat resistance and temperature characteristics of the diaphragm can be stabilized.
[0018]
The invention according to claim 7 of the present invention is such that the cross-linkable elastomer is a hydrocarbon elastomer. With this configuration, the internal loss of the diaphragm can be increased.
[0019]
The invention according to claim 8 of the present invention is such that the cross-linkable elastomer is a fluorine-based elastomer. With this configuration, the mold releasability and heat resistance of the diaphragm can be particularly improved.
[0020]
According to a ninth aspect of the present invention, the cross-linked elastomer is composed of two or more types of elastomers according to the fifth to eighth aspects. With this configuration, it is possible to freely set a low elastic modulus and a high internal loss of the diaphragm.
[0021]
The invention according to claim 10 of the present invention is a multilayer structure in which one or more elastomer layers are provided on two or more resin substrates. With this configuration, it is possible to further improve the low elastic modulus and high internal loss of the diaphragm, and further freely set the values.
[0022]
According to an eleventh aspect of the present invention, a speaker is configured using the speaker diaphragm according to any one of the first to tenth aspects. With this configuration, by reducing the elastic modulus and the high 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. Furthermore, the productivity of the speaker can be improved.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0024]
(Embodiment 1)
Hereinafter, the first and third aspects of the present invention will be described with reference to the first embodiment.
[0025]
FIG. 1 shows a speaker diaphragm 27 according to Embodiment 1 of the present invention. That is, the invention described in claim 1 is configured such that the diaphragm layer 27 a is configured by providing the elastomer layer 31 on the surface of the disk-shaped resin base material 30. Here, the resin substrate 30 is made of a resin having a Young's modulus of 2500 MPa or more, an internal loss of 0.03 or less , and a thickness of 60% to 90% of the whole . With this configuration, it is possible to realize a diaphragm that can satisfy a low elastic modulus and a high internal loss.
[0026]
And this diaphragm material 27a is pressure-air-formed along the pressure-air forming mold 40 as shown in FIG. 1 (b), and the speaker diaphragm 27 is configured as shown in FIG. 1 (c). .
[0027]
Thus, the resin base material 30 can be used as long as it has a known Young's modulus of 2500 MPa or more and an internal loss of 0.03 or less. Although many of resins generally called engineering plastics such as PEI and aromatic polyimide can be mentioned, PEI having a relatively low Young's modulus and small internal loss increases internal loss by providing the elastomer layer 31. Is preferable.
[0028]
Moreover, the production efficiency can be improved by configuring the speaker diaphragm 27 by pressure forming.
[0029]
Next, the invention described in claim 3 is configured such that the speaker diaphragm 27 is formed by using the resin base material 30 as polyetherimide (PEI). With this configuration, the speaker diaphragm 27 can be used as a countermeasure against cracks due to its characteristics as a material suitable for pressure forming of polyetherimide (PEI), which is the resin base material 30, and its effect as a highly reliable physical property. Can be improved. Moreover, it is very preferable in terms of physical properties.
[0030]
Next, the details of the elastomer layer 31 will be described.
[0031]
In the invention according to claim 4, the elastomer layer 31 is a cross-linked elastomer. With this configuration, the mold releasability of the speaker diaphragm 27 can be improved. That is, a cross-linked elastomer is preferable in that the adhesiveness to the pressure molding die 40 at the time of secondary molding (molding into a diaphragm shape) in FIG.
[0032]
In the invention according to claim 5 of the present invention, the crosslinked elastomer is a urethane elastomer. With this configuration, the cost of the speaker diaphragm 27 can be reduced. For this reason, if a cross-linked elastomer having a molecular weight between cross-linking points is too small, there is a problem that it cannot be molded into a dome shape. Therefore, hydrolytic condensation type (moisture-curing) urethane with relatively high molecular weight between crosslinking points, hydrolytic condensation type silicone, addition reaction type silicone, peroxide vulcanized silicone, hydrolytic condensation type hydrocarbon elastomer What hardened | cured (for example, isobutylene type, isoprene type) is more preferable.
[0033]
The invention described in claim 6 is a silicone elastomer as the cross-linked elastomer. With this configuration, the heat resistance and temperature characteristics of the speaker diaphragm 27 can be stabilized.
[0034]
The invention according to claim 7 of the present invention is such that the cross-linkable elastomer is a hydrocarbon elastomer. With this configuration, the internal loss of the speaker diaphragm 27 can be increased.
[0035]
The invention according to claim 8 of the present invention is such that the cross-linkable elastomer is a fluorine-based elastomer. With this configuration, the mold releasability and heat resistance of the speaker diaphragm 27 can be particularly improved.
[0036]
Among these, the most preferable combination is a combination of PEI as the resin base material 30 and hydrolytic condensation type urethane as the elastomer layer 31 in consideration of cost, expansion of internal loss, and reduction of adhesiveness at the time of molding. Further, although the cost is high, PEI is preferable as the resin base material 30 and silicone (a cured form is not limited) is preferable as the elastomer layer 31 in terms of heat resistance.
[0037]
(Embodiment 2)
In the following, the second aspect of the present invention, in particular, the second and ninth aspects of the present invention will be described.
[0038]
FIG. 2 shows a cross-sectional view of speaker diaphragm 27A according to Embodiment 2 of the present invention. According to the second aspect of the present invention, as shown in FIG. 2, the speaker diaphragm 27A is formed by providing the elastomer layers 31A and 31B on both surfaces of the resin substrate 30. As shown in FIG. With this configuration, it is possible to achieve further lower elastic modulus and higher internal loss due to the effects over both surfaces of the speaker diaphragm 27A.
[0039]
According to a ninth aspect of the present invention, the cross-linked elastomer is two or more types of elastomers according to the fifth to eighth aspects. With this configuration, it is possible to freely set the low elastic modulus and high internal loss of the speaker diaphragm 27A.
[0040]
(Embodiment 3)
Hereinafter, the invention according to the tenth aspect of the present invention will be described with reference to the third embodiment.
[0041]
FIG. 3 shows a cross-sectional view of the speaker diaphragm 27B according to Embodiment 3 of the present invention. In the invention according to claim 10 of the present invention, as shown in FIG. 3, two or more resin base materials 30A and 30B are provided with one or more elastomer layers 31C and 31D to form a multilayer structure. With this configuration, the low elastic modulus and high internal loss of the speaker diaphragm 27B can be further improved, and the values can be freely set.
[0042]
(Embodiment 4)
Hereinafter, the fourth aspect of the present invention will be described with reference to the eleventh aspect of the present invention.
[0043]
FIG. 4 shows a cross-sectional view of the loudspeaker according to Embodiment 4 of the present invention. According to an eleventh aspect of the present invention, a speaker is configured using any one of the speaker diaphragms 27, 27A, and 27B according to the first to tenth aspects.
[0044]
In the loudspeaker of FIG. 4, a magnetized magnet 21 is sandwiched between an upper plate 22 and a yoke 23 to constitute an internal magnet type magnetic circuit 24. A ring-shaped frame 26 is coupled to the yoke 23 of the magnetic circuit 24. The outer periphery of the disc-shaped speaker diaphragm 27 according to any one of claims 1 to 10 is bonded to the peripheral edge of the frame 26.
[0045]
The upper end of the cylindrical voice coil 28 is coupled to the speaker diaphragm 27 and the lower portion of the voice coil 28 is coupled so as to fit into the magnetic gap 25 of the magnetic circuit 24.
[0046]
According to this configuration, the speaker diaphragm 27 has a low elastic modulus and a high internal loss, thereby improving the sound quality and characteristics of the speaker, expanding the low-frequency reproduction band, and reducing unnecessary resonance. can do.
[0047]
Next, the material thickness of the speaker diaphragm 27 used in the present invention will be described. The material thickness of the diaphragm is not limited to the following, but when used for a small speaker, it is generally 100 μm or less, preferably 50 μm or less, and most preferably 30 μm or less. Moreover, when it becomes too thin, problems, such as dimensional accuracy, will generate | occur | produce.
[0048]
The thickness balance between the resin base material 30 and the elastomer layer 31 is such that the thickness of the diaphragm is larger than necessary when the sound pressure is secured when the speaker is configured unless the thickness of the resin base material 30 is 50% or more. turn into. If it is 95% or more, it is difficult to obtain the effect of the elastomer layer 31. Preferably, the thickness of the resin base material 30 excluding the elastomer layer 31 is 60% to 90% of the whole.
[0049]
When the speaker diaphragms 27, 27A, 27B according to the present invention are formed in an inverted dish shape as shown in FIGS. 1 to 4, the internal loss of the material increases, rolling is prevented, and high sound quality and low F0 can be supported. It becomes. Further, it is possible to provide a speaker that can satisfy the performance required for a micro speaker represented by a mobile phone or a general speaker.
[0050]
【The invention's effect】
As described above, the speaker diaphragm of the present invention is formed by pressure-compressing a material having a multilayer structure in which an elastomer layer is provided on both sides or one side of a resin base having a thickness of 60% to 90%. It is a thing. Furthermore, a speaker is configured using this speaker diaphragm.
[0051]
With these configurations, it is possible to realize wide frequency characteristics and good sound quality. Therefore, it is possible to provide an excellent speaker that can satisfy the performance required for a micro speaker typified by a cellular phone or a general speaker, and its industrial value is very large.
[Brief description of the drawings]
FIGS. 1A to 1C are cross-sectional views showing a production process of a speaker diaphragm according to an embodiment of the present invention. FIG. 2 are diagrams of speaker diaphragms according to another embodiment of the present invention. FIG. 3 is a cross-sectional view of a speaker diaphragm according to still another embodiment of the present invention. FIG. 4 is a cross-sectional view of a speaker according to an embodiment of the present invention. Sectional view [Explanation of symbols]
21 magnet 22 upper plate 23 yoke 24 magnetic circuit 25 magnetic gap 26 frame 27 speaker diaphragm 27a diaphragm member 27A speaker diaphragm 27B speaker diaphragm 28 voice coil 30 resin substrate 30A resin substrate 30B resin substrate 31 elastomer Layer 31A Elastomer layer 31B Elastomer layer 31C Elastomer layer 31D Elastomer layer 40 Mold for pressure air molding

Claims (11)

Young's modulus is more than 2500 MPa, and an internal loss is 0.03 or less, a thickness of the resin base material is 60% to 90% of the total, a material which is configured by providing the elastomer layer was pressure molded into a desired shape A speaker diaphragm characterized by the above.   The speaker diaphragm according to claim 1, wherein an elastomer layer is provided on both surfaces of the resin base material.   The speaker diaphragm according to claim 1 or 2, wherein the resin base material is polyetherimide (PEI).   The speaker diaphragm according to any one of claims 1 to 3, wherein the elastomer layer is a cross-linked elastomer.   5. The speaker diaphragm according to claim 4, wherein the cross-linked elastomer is a urethane elastomer.   5. The speaker diaphragm according to claim 4, wherein the cross-linked elastomer is a silicone elastomer.   The speaker diaphragm according to claim 4, wherein the cross-linked elastomer is a hydrocarbon elastomer.   The speaker diaphragm according to claim 4, wherein the cross-linked elastomer is a fluorine-based elastomer.   The loudspeaker diaphragm according to claim 1 or 2, wherein an elastomer layer is constituted by two or more types of cross-linked elastomers according to claims 5 to 8.   The speaker diaphragm according to any one of claims 1 to 9, wherein the speaker diaphragm has a multilayer structure including two or more resin base materials and one or more elastomer layers.   A speaker using the speaker diaphragm according to any one of claims 1 to 10.

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