JP2011142671A - Loudspeaker diaphragm, loudspeaker employing the same, and electronic equipment and apparatus employing the loudspeaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a loudspeaker diaphragm, loudspeaker, electronic equipment and apparatus, used for an acoustic apparatus capable of producing the characteristics and sound of high accuracy. <P>SOLUTION: By configuring the loudspeaker diaphragm through injection molding of a material obtained by blending at least a resin material and a bamboo fiber, a diaphragm can be achieved so that the features of both the advantage of bamboo fiber, with high sound quality and with large freedom degree for setting of physical property values of the diaphragm, and the advantage of a resin diaphragm, which can ensure moisture-proof reliability and strength, is superior in appearance, and can also enhance productivity and dimensional stability, can be effectively utilized. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a speaker diaphragm used in various audio equipment and video equipment, and to electronic equipment and devices such as a speaker, a stereo set, and a television set using the diaphragm.

  A conventional technique will be described with reference to FIG.

  FIG. 6 is a cross-sectional view of a resin speaker diaphragm made by conventional injection molding. As shown in FIG. 6, the speaker diaphragm 21 was obtained by using a resin such as polypropylene and injection-molding resin pellets in a pre-set mold. In addition, as a kind of resin material by these injection molding, single material, such as a polypropylene, is generally used well.

  In addition, there are blend types using different types of resins for the purpose of adjusting the physical properties of the diaphragm, that is, adjusting the characteristics and sound quality of the speaker.

  Furthermore, with respect to the adjustment of physical property values that are difficult to adjust with these resins, reinforcing materials such as mica are mixed to adjust the physical property values and the characteristics and sound quality as a speaker. Further, in order to further increase the degree of freedom in adjusting the physical properties, the sound quality is adjusted by mixing pulp material.

  As prior art document information related to the invention of this application, for example, Patent Documents 1 and 2 are known.

Japanese Patent Application Laid-Open No. 59-17695 JP 2005-236497 A

  With respect to recent audio equipment and video equipment, as well as devices such as automobiles equipped with these equipment, performance has been dramatically improved as compared with the past due to significant advances in digital technology.

  With regard to its sound quality, the realization has been further increased with lower distortion, wider bandwidth, and higher dynamic range, and video performance has been improved dramatically due to the high definition and the emergence and popularization of large modules such as plasma displays. . Therefore, due to the improvement in performance of the electronic devices described above, there is a strong demand from the market to improve the performance of speakers used in these electronic devices.

  On the other hand, for a speaker whose performance is strongly demanded by the market, it is indispensable to improve the performance of a diaphragm that occupies a large weight that determines the sound quality among the components of the speaker.

  However, this vibration plate uses a traditional paper manufacturing method or a resin injection molding or press manufacturing method, and therefore, the paper vibration plate or the resin vibration plate has been mainly used. For this reason, these diaphragms have been used properly according to their applications while taking advantage of their respective characteristics. However, these diaphragms have their respective disadvantages and do not satisfy the aforementioned market requirements.

  That is, in the paper diaphragm, the physical property value of the diaphragm can be set finely, and there is an advantage that the degree of freedom of adjustment of the characteristics and sound quality as a speaker is large, but it is inferior in moisture resistance reliability and strength, which are defects inherent in paper Has drawbacks.

  In addition, the production has a disadvantage that it cannot be obtained unless a very large number of processes such as paper making are required.

  On the other hand, with resin diaphragms, moisture resistance reliability and strength can be ensured, appearance can be improved, productivity can be improved, but only uniform physical properties specific to resin, which is the fate of resin, can be secured. There is a drawback that the adjustment range of the characteristics and sound quality as a speaker is very narrow.

  In addition, a diaphragm mixed with resin and pulp material provides greater freedom of sound quality adjustment and ensures moisture resistance reliability. However, in order to improve physical properties and sound quality, it is necessary to increase the strength. was there.

  The present invention solves the above-described problems, and provides a speaker diaphragm that has a large degree of freedom in adjusting characteristics and sound quality as a speaker, can ensure moisture resistance reliability and strength, has an excellent appearance, and can improve productivity. It is intended to provide.

  In order to achieve the above object, the present invention comprises a resin diaphragm and bamboo fiber, and the bamboo fiber is formed by injection molding a material that is at least partially refined into a microfibril state to constitute a speaker diaphragm. ing. As a result, the intended purpose can be achieved.

  As described above, the present invention is a speaker diaphragm including a resin, bamboo fiber, and bamboo fiber partially refined to a microfibril state, and the mixing ratio of the bamboo fiber to the resin is 5% by weight. The bamboo diaphragm is made to have a fiber length of 0.2 mm to 3 mm and an average fiber diameter of 10 μm or less.

  With this configuration, the strength is increased because the bamboo fiber is at least partially refined to a microfibril state, and the high strength and high elastic modulus of the bamboo fiber can be efficiently exhibited in the resin. High internal loss can be realized and sound quality is improved. In addition, while maintaining the moisture resistance and water resistance that are the characteristics of the resin diaphragm, the degree of freedom in setting the physical properties of the diaphragm can be increased, and a diaphragm having an excellent appearance can be obtained.

  Furthermore, a diaphragm having improved productivity and dimensional stability can be obtained by obtaining the diaphragm by injection molding.

  Furthermore, by selecting these resins and reinforcing materials that are mixed materials from a wide variety of materials and setting the blending ratio appropriately, it is possible to achieve high-precision characteristics and The sound quality can be adjusted.

  In addition, various designs are possible by combining the designs such as colors. And the combination enables the setting of unlimited variations, and the desired requirements can be satisfied in characteristics creation, sound creation, and design.

Sectional drawing of the diaphragm for speakers in one embodiment of this invention The top view of the diaphragm for speakers in one embodiment of the present invention Sectional drawing of the speaker in one embodiment of this invention 1 is an external view of an electronic device according to an embodiment of the present invention. Sectional drawing of the mobile body apparatus in one embodiment of this invention Sectional view of a conventional speaker diaphragm made by injection molding

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
Hereinafter, the present invention will be described using the first embodiment. FIG. 1 is a sectional view of a diaphragm according to an embodiment of the present invention, and FIG. 2 is a plan view of the diaphragm according to an embodiment of the present invention. As shown in FIGS. 1 and 2, the diaphragm 1 is formed by injection molding a material in which a resin 1A, bamboo fibers 1B, and bamboo fibers 1C refined to a microfibril state are mixed.

  Here, for the diaphragm 1, it is preferable to use a crystalline or amorphous olefin resin as the resin 1 </ b> A. By using an olefin resin, moldability is improved. In addition, by appropriately using a crystalline resin and an amorphous resin according to applications, it is possible to satisfy the optimum physical property values as a resin material.

  Bamboo fiber can reproduce a natural and bright tone, can suppress dark and uniform tone unique to resin, and has a higher elastic modulus than other pulp materials, so the physical properties can be freely adjusted. The degree is increased.

  Furthermore, in addition to bamboo fiber, bamboo fiber refined to the microfibril state of bamboo fiber is mixed to improve the entanglement between the bamboo fibers, resulting in increased strength and elastic modulus. The degree of freedom of sound quality adjustment as a diaphragm is also increased.

  Below, the example which uses a polypropylene for resin 1A is demonstrated. Polypropylene is generally easily available and injection molding is easy, but in the present invention, the resin is not limited to polypropylene, and engineering plastics and biodegradable plastics typified by polylactic acid may be used for environmental considerations. .

  Here, it is preferable that the length of the bamboo fiber 1C refined to the microfibril state is 0.2 mm or more and 3 mm or less. By using bamboo fiber 1C in this length range, the effect when combined with resin 1A by heat granulation is efficiently exhibited, and productivity and quality are improved.

  Specifically, when the fiber length of the bamboo fiber 1C is shorter than 0.2 mm, the effect of the bamboo fiber 1C cannot be obtained efficiently and a high elastic modulus cannot be expected. On the other hand, when the length is longer than 3 mm, poor dispersion tends to occur due to secondary aggregation resulting from the entanglement of the bamboo fibers 1C. Therefore, a long time is required for kneading with the resin 1A. Alternatively, an aggregate of bamboo fibers 1C appears on the surface of the diaphragm 1 and the appearance is impaired. Thus, productivity and quality are reduced.

  Moreover, it is desirable that the average fiber diameter of the bamboo fiber 1C refined to the microfibril state is 10 μm or less. In general, the fiber has higher elasticity when the aspect ratio (L / D), which is the ratio between the fiber length L and the fiber diameter D, is higher, and the bamboo fiber 1C, which is made finer to microfibrils, has a higher aspect ratio, so it can be expected to have higher elasticity. .

  In addition, the presence of bamboo fibers 1C that are partially refined to microfibrils also has the effect of strengthening the bond between the fibers, and these are synergistically high in elasticity.

  In addition, when it is desired to increase the bamboo fiber 1B to make the tone more natural and bright, bamboo powder may be used for a part or all of the bamboo fiber 1B. By using bamboo powder, a decrease in fluidity can be suppressed, and moldability can be secured. Here, the bamboo powder does not have an aspect ratio (fiber length / fiber diameter) but refers to granular bamboo fibers obtained by pulverizing the bamboo powder.

  Furthermore, the mixing ratio of the bamboo fiber 1B to the resin 1A is preferably 5% by weight or more and 60% by weight or less. By setting this blending ratio range, the effect when kneaded with the resin 1A is efficiently exhibited, and the productivity and quality are improved.

  When the mixing ratio of the bamboo fiber 1B is less than 5% by weight, the effect of the bamboo fiber 1B hardly appears. On the other hand, when it exceeds 60% by weight, it takes a long time for kneading with the resin 1A. Further, since injection molding becomes difficult, productivity and dimensional stability are reduced, and the degree of freedom in shape is reduced.

  Furthermore, in the case where it is desired to adjust the sound quality by reinforcing the diaphragm 1, adding some accents to the sound, or giving the sound pressure frequency characteristics a peak, a reinforcing material may be mixed. As such a reinforcing material, mica, graphite, talc, calcium carbonate, clay, carbon fiber, and aramid fiber can be used.

  When mica is mixed into the reinforcing material, the elastic modulus can be increased. When graphite is mixed, the elastic modulus and internal loss can be increased. When talc, calcium carbonate, and clay are mixed, internal loss can be increased.

  Moreover, you may use strong fiber like carbon fiber as a fiber. When carbon fiber is mixed, rigidity increases and elastic modulus improves. Alternatively, if an aramid fiber is used, the bamboo fiber and the aramid fiber are entangled during heating granulation, and the internal loss can be increased without lowering the elastic modulus. In addition, when an aramid fiber refined to a microfibril state is used, the aspect ratio (fiber length L / fiber diameter D) is large, and the entanglement between fibers becomes strong, so that a high elastic modulus and a high internal loss are possible.

  Moreover, by using a compatibilizing agent, it becomes possible to increase the compatibility of a non-polar resin such as PP and bamboo fiber, and to efficiently exhibit the characteristics of bamboo fiber. In particular, it is desirable to use a hydrolyzable long-chain alkylsilane as the compatibilizer. This is because the long-chain alkyl group of the hydrolyzable long-chain alkyl silane is structurally similar to olefin resins such as PP, so the compatibility is improved. As a result, the compatibility with bamboo fiber is also increased. Will improve. Further, the compatibilizing agent is not limited to this, and it goes without saying that so-called modified PP modified with a silane coupling agent or maleic anhydride to have polarity may be used.

  In addition, by combining these materials, the physical property value of the diaphragm 1 can be adjusted freely and with high accuracy, and predetermined characteristics and sound quality can be realized. In order to realize the predetermined characteristics and sound quality, deep know-how regarding characteristics creation and sound creation is necessary, but in general, it is often performed by the following method. That is, the speaker characteristics and sound can be changed to some extent by changing the parameters of the components, and can be brought close to predetermined characteristics and sound quality.

  For example, a case is assumed in which the parameters of the components other than the diaphragm 1 among the speaker components are fixed. Parameters that can be varied in the diaphragm 1 are area, shape, weight, surface thickness, etc., other than the physical property values. However, the area, shape, weight, and surface thickness of the diaphragm 1 are almost determined at the initial stage of speaker design. That is, the sound pressure frequency characteristic and sound quality of the speaker are roughly determined by conditions other than the physical property values of the diaphragm 1.

  In this case, unnecessary peaks and dips occur in the sound pressure frequency characteristics, and distortion often occurs greatly in a specific frequency band. As for the sound quality, the timbre greatly depends on the sound pressure frequency characteristic. These causes are caused by the area, shape, weight, and surface thickness of the diaphragm 1, and in particular, are often due to the vibration mode of the diaphragm 1. When selecting a diaphragm material in order to improve such unnecessary peaks, dips and distortions and obtain good sound quality, the following procedure can be followed.

  First, a material that can satisfy the sound pressure frequency characteristics, sound quality, and reliability grade required for the speaker is selected as a resin, bamboo fiber 1B, and other mixed materials. In this case, the resin used as a base is selected with particular emphasis on reliability such as its heat resistance grade, and a material whose specific tone color of each resin is close to a predetermined tone color is selected.

  And each material is selected about the unnecessary peak and dip on the sound pressure frequency characteristic to delete. For countermeasures against dip, a resin material having resonance at that frequency is selected. Conversely, for countermeasures against peaks, a material having internal loss at that frequency is selected. About this material selection, resin, bamboo fiber 1B, and other mixed materials are selected in consideration of the density, elastic modulus, internal loss, timbre, resonance frequency when molded into the shape of diaphragm 1, etc. .

  And the selected material is knead | mixed and the masterbatch pellet highly filled with the bamboo fiber for injection molding is produced. Next, using this master batch pellet, the diaphragm 1 is obtained by injection molding.

  The physical property values and the like of the diaphragm 1 thus obtained are measured and evaluated. In addition, a speaker is prototyped using the diaphragm 1, and the characteristics and sound quality are actually measured. If the predetermined characteristics and sound quality cannot be obtained by the evaluation, this prototype process is repeated many times. And in that, we will improve the selection of materials and their blending ratio, and gradually bring them closer to the target characteristics and sound quality.

  By repeating the process as described above, it is possible to finish the diaphragm 1 that satisfies the predetermined characteristics and sound quality or is very close.

  Polypropylene is generally easily available and injection molding is easy, but the present invention is not limited to this resin material and can be used properly according to the desired characteristic value. Furthermore, when high heat resistance and high solvent resistance are required, it is possible to use an engineering plastic suitable for the application. Alternatively, biodegradable plastics, particularly polylactic acid can be used for environmental considerations. Here, polylactic acid has relatively better compatibility with bamboo fibers than PP, and the compatibility is further improved by using tannin or the like as a compatibilizing agent.

  As described above, the present invention increases the degree of freedom in setting the physical properties of the diaphragm by injection molding the material mixed with resin and bamboo fiber 1B to configure the speaker diaphragm. While taking advantage of the high elastic modulus, which is a feature, it is possible to obtain a diaphragm that ensures high internal loss and moisture resistance reliability of the resin, has excellent appearance, and can improve productivity and dimensional stability.

(Embodiment 2)
Hereinafter, the present invention will be described using the second embodiment. FIG. 3 shows a cross-sectional view of a speaker according to an embodiment of the present invention. As shown in FIG. 3, a magnetized magnet 2 is sandwiched between an upper plate 3 and a yoke 4 to constitute an internal magnet type magnetic circuit 5.

  A frame 7 is coupled to the yoke 4 of the magnetic circuit 5. The outer periphery of any one of the diaphragms 1 to 18 is bonded to the peripheral portion of the frame 7 via an edge 9. One end of the voice coil 8 is coupled to the center of the diaphragm 1 and the other end is coupled so as to fit into the magnetic gap 6 of the magnetic circuit 5.

  Although the speaker 10 having the inner magnet type magnetic circuit 5 has been described above, the present invention is not limited to this, and the present invention may be applied to a speaker having an outer magnet type magnetic circuit.

  With this configuration, as described in the first embodiment, the degree of freedom in adjusting characteristics and sound quality is great, moisture resistance reliability and strength can be ensured, and a speaker with excellent appearance and high productivity can be realized. .

(Embodiment 3)
Hereinafter, the present invention will be described using the third embodiment. FIG. 4 shows an external view of an audio minicomponent system that is an electronic apparatus according to an embodiment of the present invention.

  The speaker 10 is incorporated in the enclosure 11 to constitute a speaker system 21. The amplifier 12 includes an amplification circuit for an electric signal input to the speaker system 21. An operation unit 13 such as a player outputs a source input to the amplifier 12. As described above, the audio mini-component system 14 that is an electronic device includes the amplifier 12, the operation unit 13, and the speaker system 21. The amplifier 12, the operation unit 13, and the enclosure 11 are main body units of the mini component system 14. That is, the speaker 10 is attached to the main body of the mini component system 14. The voice coil of the speaker 10 is supplied with power from the amplifier 12 of the main body and emits sound from the diaphragm. With this configuration, it is possible to obtain a mini component system 14 that enables high-precision characteristic creation, sound creation, and design that could not be realized in the past.

  In addition, although the audio | voice minicomponent system 14 was demonstrated as an application to the apparatus of the speaker 10, it is not limited to this. It can also be applied to portable audio devices that can be carried and charging systems. Furthermore, it can be widely applied and deployed in video equipment such as liquid crystal televisions and plasma display televisions, information communication equipment such as mobile phones, and electronic equipment such as computer-related equipment.

(Embodiment 4)
Hereinafter, the present invention will be described using the fourth embodiment.

  FIG. 5 shows a cross-sectional view of an automobile 50 that is a mobile device according to an embodiment of the present invention. As shown in FIG. 5, an automobile 50 is configured by incorporating the speaker 10 of the present invention into a rear tray or a front panel and using it as a part of car navigation or car audio.

  By adopting this configuration, it is possible to improve the sound quality and improve the degree of freedom in acoustic design of mobile devices such as automobiles equipped with this speaker 10 by creating highly accurate characteristics, making sound, and designing utilizing the features of the speaker 10. Can be improved.

  The speaker diaphragm, the speaker, the electronic device, and the device according to the present invention can be applied to an electronic device such as an audiovisual device or an information communication device that requires highly accurate characteristics and sound creation, and further to a device such as an automobile.

DESCRIPTION OF SYMBOLS 1 Diaphragm 1A Resin 1B Bamboo fiber 1C Microfibrillated bamboo fiber 2 Magnet 3 Upper plate 4 Yoke 5 Magnetic circuit 6 Magnetic gap 7 Frame 8 Voice coil 9 Edge 10 Speaker 11 Enclosure 12 Amplifier 13 Player 14 Mini component system 50 Automobile

Claims (18)

A diaphragm for a speaker including a resin, a bamboo fiber, and a bamboo fiber partially refined to a microfibril state, wherein the mixing ratio of the bamboo fiber to the resin is 5 wt% or more and 60 wt% or less, A speaker diaphragm having a fiber length of 0.2 mm to 3 mm, and an average fiber diameter of 10 μm or less, wherein the bamboo fiber is partially refined to a microfibril state. The speaker diaphragm according to claim 1, wherein the speaker diaphragm is formed by injection molding. 2. The loudspeaker diaphragm according to claim 1, wherein the resin is a crystalline or amorphous olefin resin. 2. The speaker diaphragm according to claim 1, wherein the resin is polypropylene. The speaker diaphragm according to claim 1, wherein the resin is an engineering plastic. 2. The loudspeaker diaphragm according to claim 1, wherein the resin is a biodegradable plastic. 2. The loudspeaker diaphragm according to claim 1, wherein the biodegradable plastic is polylactic acid. The speaker diaphragm according to claim 1, wherein at least a part of the bamboo fiber is bamboo powder. The speaker diaphragm according to claim 1, further comprising a reinforcing material. The speaker diaphragm according to claim 9, wherein the reinforcing material is made of at least one of mica, graphite, talc, calcium carbonate, clay, carbon fiber, and aramid fiber. The speaker diaphragm according to claim 10, wherein the reinforcing material has an aramid fiber length of 0.2 mm to 3 mm. The speaker diaphragm according to claim 11, wherein the aramid fiber is at least partially made fine to a microfibril state having a fiber diameter of 5 μm or less. The speaker diaphragm according to claim 1, further comprising a compatibilizing agent that improves adhesion between the resin and the bamboo fiber. 14. The loudspeaker diaphragm according to claim 13, wherein the compatibilizing agent is a hydrolyzable long-chain alkylsilane. A magnetic circuit, a frame coupled to the magnetic circuit, a diaphragm according to claim 1 coupled to an outer peripheral portion of the frame, and the diaphragm coupled to the diaphragm, and part of the diaphragm is generated from the magnetic circuit. A speaker comprising a voice coil disposed within a range of action of magnetic flux. A main body, a magnetic circuit, a frame coupled to the magnetic circuit, the diaphragm according to claim 1 coupled to an outer peripheral portion of the frame, and the diaphragm are coupled to the diaphragm, and a part thereof is formed from the magnetic circuit. An electronic apparatus comprising: a voice coil disposed within a range of action of generated magnetic flux, and a speaker fed from the main body. The electronic device according to claim 16, wherein the main body portion includes a circuit that amplifies at least an input signal to the speaker. The main body includes a body, a drive unit provided on the body, a drive wheel that is driven by the drive unit and supports the body, a steering provided on the body, and a steering wheel operated by the steering. A mobile device comprising the speaker according to claim 15 provided inside the body.

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