JP2009302924A - Transducer for planar speaker, plane speaker, screen and advertising banner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transducer for a planar speaker, capable of making compatible high allowable input and high conversion efficiency by enabling heat generated from a voice coil to be radiated easily and effectively, and to provide a planar speaker employing the same, screen and advertising banner. <P>SOLUTION: A transducer 11 of a planar speaker comprises a transducer body 11a and a planar auxiliary diaphragm 11b, constituted of a high heat conductivity material. The transducer body 11a is adhered to a diaphragm 12 of the plane speaker, while interposing the auxiliary diaphragm 11b therebetween, thereby markedly increasing heat radiating paths for generated heat (heat radiation amount) from the voice coil 1 of the transducer body 11a relative to prior art. By configuring the planar speaker, a screen and an advertising banner, the heat-radiating effect thereof is improved by using the transducer 11. The diaphragm 12 of the planar speaker is formed from a bendable object and enables a portion of the diaphragm 12 to be wrapped/deployed, thereby attaining convenience in carrying or housing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a transducer used for a speaker that converts an electrical signal into sound (sound current is vibration), and more particularly to a flat speaker transducer, a flat speaker using the transducer, a screen, and an advertisement banner.

Conventionally, as a technique related to a flat speaker, for example, there is one described in Patent Document 1.
This is a speaker that includes a panel-shaped member (diaphragm) and a transducer attached to the member, and the transducer causes the member to resonate to form an acoustic radiator.

Japanese Patent Laying-Open No. 2005-198342 (particularly FIG. 11c)

The transducer that constitutes the speaker receives sound current and converts it into vibration, and generates heat during operation. In particular, the increase in the amount of heat generated from the voice coil during a long time or high output operation is remarkable.
In general speakers, heat dissipation due to vibration of cone paper used as a diaphragm can be expected, but in a flat speaker, heat dissipation due to the diaphragm cannot be expected due to its configuration.
If the heat radiation is insufficient, there is a risk that the voice coil will be destroyed by melting the insulation coating or adhesive on the voice coil portion constituting the transducer. In order to avoid this, it is conceivable to reduce the heat generation amount itself by lowering the allowable input to the voice coil. However, since this limits the output, conventionally, there has been a problem with measures against heat generation from the voice coil.

This will be described below with reference to FIG.
In the flat speaker, the heat generated from the voice coil 1 constituting the transducer 71 is dissipated by circulation through the magnetic gap 2 due to air convection in the magnetic circuit (arrow A) and radiation from the voice coil bobbin 3 (arrow A). Is done. Further, the amount of heat generated from the voice coil 1 can be reduced by lowering the resistance value of the voice coil conductor (conductive wire forming the voice coil 1).
For this reason, it is possible to cope with the heat generation from the voice coil 1 without lowering the allowable input by widening the magnetic gap 2 to lower the thermal resistance and thickening the voice coil lead wire to lower the resistance value to suppress the heat generation. On the other hand, from the viewpoint of increasing the efficiency of voice current / sound conversion (high conversion efficiency), the magnetic gap 2 is narrow, and it is effective that the voice coil conductor is wound into the magnetic gap 2 to be thinner and denser. This means that it is extremely difficult to achieve both high allowable input and high conversion efficiency.

By increasing the heat resistance of the voice coil conductor insulation coating, voice coil bobbin 3 and voice coil fixing adhesive, it is possible to cope with heat generation from the voice coil 1 without widening the magnetic gap 2 or thickening the voice coil conductor. It is thought that it is possible to achieve both high allowable input and high conversion efficiency. However, this method complicates the design, production, and the like. Therefore, conventionally, it is possible to deal with the heat generated from the voice coil 1 more easily and effectively than this, and a flat speaker that can achieve both high allowable input and high conversion efficiency. Development of a transducer was desired.
In FIG. 7, 4 is a magnet, 5 is a pole piece, 6 is a yoke, 7 is a frame, 8 is a damper, and 10 is a sub-plate, each of which is a component of the transducer 71. Reference numeral 12 denotes a diaphragm.

  The present invention provides a simple and effective voice coil without particularly changing the width of the magnetic gap, the thickness of the voice coil conductor, the insulation coating of the voice coil conductor, the heat resistance of the voice coil bobbin and the adhesive for fixing the voice coil, etc. An object of the present invention is to provide a flat speaker transducer capable of dissipating heat generated from the above, and having both a high allowable input and high conversion efficiency, a flat speaker using the same, a screen, and an advertisement banner.

In order to achieve the above object, a flat speaker transducer according to claim 1 is a flat speaker transducer including a flat diaphragm, and the transducer includes a transducer body, a high thermal conductivity, A planar auxiliary diaphragm made of an index material, and the transducer body is attached to the diaphragm with the auxiliary diaphragm interposed so that heat generated from the transducer body can be conducted. It is characterized by.
The “plate” in the diaphragm includes materials such as a film, a sheet, and a fiber structure in addition to a general plate-like body.
For example, as the film or sheet, a film or sheet made of polyester such as polyethylene terephthalate or polyethylene naphthalate, polyolefin, or vinyl chloride can be used.
In addition, the fiber structure includes articles in the form of woven fabric, knitted fabric, non-woven fabric, etc., and woven fabric is particularly preferable. Examples of fibers constituting the fiber structure include polyester fibers such as polyethylene terephthalate fibers and polyethylene naphthalate fibers, aromatic polyamide fibers, aliphatic polyamide fibers, polyolefin fibers, PBO fibers, and carbon fibers. In particular, those using polyester fibers such as polyethylene terephthalate fibers and polyethylene naphthalate fibers are preferable from the viewpoints of acoustic effect, light resistance, cost, and handleability.
Basis weight of the fiber structure is preferably in the range of 50 to 500 g / m ^2. Further, when the fiber structure is a woven fabric, it is preferable that the weave density is 10 to 30 / inch in both the weft direction and the weft direction. The weave density in the warp and weft directions may be the same or different.
The fiber structure may be impregnated with a urethane resin, an acrylic resin, a melamine resin, an unsaturated polyester resin, a saturated polyester resin, or the like as necessary in order to improve the fiber convergence.
Further, one or both surfaces of the fiber structure may be laminated or coated with vinyl chloride resin, polyester resin, polyolefin resin, acrylic resin, urethane resin, or the like. These resins can contain dyes and pigments, thereby imparting functionality and design to the fiber structure.
Since the film, sheet, and fiber structure described above have flexibility and flexibility, when used in a diaphragm, the film, sheet, and fiber structure can be freely wound and unfolded and can be reduced in weight.
The auxiliary diaphragm handles the heat generated by the transducer (mainly the voice coil) in addition to the acoustic function to transmit the vibration of the transducer to the diaphragm more efficiently and efficiently. The heat sink function is added, and is formed of a high thermal conductivity material.
FIG. 4 shows the heat conductivity [Cal / cm · ° C. · second] of a typical metal material that can be used when a metal material is used as the auxiliary diaphragm. In this figure, when contrasting each thermal conductivity of the metal material, “0.5” is shown as a remarkable boundary value. Therefore, a metal material having a thermal conductivity of “0.5” or more can be cited as a good example, but an aluminum material is preferable in consideration of cost-releasing effect, weight reduction, ease of processing, and the like.
It is desirable that the auxiliary diaphragm has a large area for the heat sink function. As shown in FIG. 5, the inventors use the same 0.8 mm thick aluminum plate as an auxiliary diaphragm, A is 33 mm long, 33 mm wide, B is 100 mm long, 60 mm wide, C is 100 mm long, horizontal 100 mm, D is a size of 100 mm in length and 120 mm in width, and the temperature rise of the voice coil when an input signal of 10 W (white noise) is continuously given for 3 hours was measured by experiment. The measurement was performed by a resistance substitution method in an environment of 20 ° C.
FIG. 6 is a graph showing the results of the above experiment (change in temperature rise with respect to the area of the auxiliary diaphragm). In the figure, A to D represent experimental result values of the auxiliary diaphragms A to D. α represents an experimental result value when the auxiliary diaphragm is not used. According to FIG. 6, it can be seen that the heat dissipation effect by the auxiliary diaphragm is substantially proportional to the area of the used auxiliary diaphragm. Therefore, the area of the auxiliary diaphragm is selected in accordance with cost-effective heat dissipation, weight reduction, ease of transducer manufacture, and the like, as in the case of selecting a metal material used as the auxiliary diaphragm. Further, the size is selected in consideration of the size of the diaphragm to which the auxiliary diaphragm is attached and the influence on the acoustic characteristics.

The flat speaker transducer according to claim 2 is the flat speaker transducer according to claim 1, wherein the high thermal conductivity material is a metal material and is subjected to embossing, bending, or surface hardening treatment. It is characterized by.
When surface hardening treatment such as embossing, bending, or alumite treatment when the metal material is an aluminum material, the rigidity is increased and a planar auxiliary vibration made of a high thermal conductivity material (metal material) An adverse effect due to the natural resonance frequency of the plate, in particular, a sharp drop in the output signal level at a specific frequency due to resonance is prevented.
When a film-like or sheet-like material is used for the diaphragm, the outline of the auxiliary diaphragm is easily seen from the acoustic radiation surface side (front side) of the diaphragm. This is because the contour of the auxiliary diaphragm becomes the boundary of the double structure portion with the diaphragm. In such a case, if the bending process is performed toward the opposite side of the diaphragm side over the entire circumference of the peripheral edge portion of the high thermal conductivity material (auxiliary diaphragm), particularly if it is performed so as to be folded back with a roundness. The outline of the auxiliary diaphragm is blurred and becomes difficult to see.

The flat speaker transducer according to claim 3 is the flat speaker transducer according to claim 1 or 2, wherein a plurality of through holes are formed in the auxiliary diaphragm.
If a plurality of through-holes are drilled, the auxiliary diaphragm is reduced in weight, and deterioration of frequency characteristics in the high range (decrease in high frequency characteristics) is prevented. This is particularly effective when a metal material is used. A through hole having a desired shape such as a round shape, an oval shape, a rectangular shape, or a slit shape can be selected.
The flat speaker according to claim 4 is characterized in that the flat speaker transducer according to any one of claims 1 to 3 is attached to a flat diaphragm.
The flat speaker according to claim 5 is the flat speaker according to claim 4, wherein the planar diaphragm has flexibility.
The flat speaker according to claim 6 is the flat speaker according to claim 4 or 5, wherein the planar diaphragm is made of a fiber structure.
The screen according to claim 7 is characterized in that the flat speaker according to any one of claims 4 to 6 is used.
The advertisement banner according to claim 8 is characterized in that the flat speaker according to any one of claims 4 to 7 is used.

  According to the first aspect of the present invention, it is possible to provide a transducer for a flat speaker that can easily and effectively dissipate heat generated from the voice coil, and can achieve both high allowable input and high conversion efficiency.

  According to the second aspect of the present invention, a sharp drop in the output signal level at a specific frequency due to resonance of the auxiliary diaphragm can be prevented by embossing, bending, or surface hardening.

According to the third aspect of the present invention, the auxiliary diaphragm is reduced in weight and can prevent deterioration of frequency characteristics in a high frequency range.
According to the fourth aspect of the present invention, there is provided a flat speaker having an advantage that the heat generated from the voice coil can be dissipated easily and effectively with respect to the transducer to be used, and both high permissible input and high conversion efficiency can be achieved. it can.
According to the fifth and sixth aspects of the invention, the flat diaphragm portion can be freely wound and unfolded, and a flat speaker excellent in carrying and storage can be provided.
According to the seventh aspect of the present invention, the transducer to be used has the advantage that heat generated from the voice coil can be dissipated easily and effectively, and both high permissible input and high conversion efficiency can be achieved. The screen-shaped diaphragm portion can be freely wound and unfolded, and a screen excellent in terms of carrying and storage can be provided.
According to the invention described in claim 8, the transducer to be used has the advantage that heat generated from the voice coil can be radiated easily and effectively, and both a high allowable input and a high conversion efficiency can be achieved. As for the diaphragm-shaped diaphragm part, it is possible to freely wind and unfold, and it is possible to provide an advertisement banner that is excellent in terms of carrying and storage. In particular, when the planar diaphragm is made of a fiber structure, it is possible to draw letters and drawings by dyeing or printing, which is very effective for an advertisement banner.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol shows the same or equivalent part between each figure referred in this specification.
FIG. 1 is an exploded perspective view of an embodiment of a flat speaker to which the present invention is applied. FIG. 2 is a two-side view [(a) is a front view, (b) is a right side view], and FIG. It is an enlarged view of a cross section.

As can be seen from these drawings, the planar speaker includes a planar diaphragm 12 and a planar speaker transducer (hereinafter abbreviated as a transducer) 11 that is attached to the diaphragm 12 to form an acoustic radiator. Prepare.
Here, the transducer 11 includes a transducer main body 11a and a planar auxiliary diaphragm 11b made of a high thermal conductivity material, and heat generated by the transducer main body 11a through the auxiliary diaphragm 11b is provided on the diaphragm 12. It is attached to be able to conduct heat. Specifically, the heat generated by the transducer body 11a is bonded to the auxiliary diaphragm 11b on the acoustic radiation side of the transducer body 11a so as to be able to conduct heat, and the auxiliary diaphragm 11b is bonded to the diaphragm 12 so as to be able to conduct heat. It is attached.
The auxiliary diaphragm 11b dissipates heat generated from the transducer body 11a (mainly a voice coil, which will be described later) in addition to a function for transmitting the vibration of the transducer body 11a to the diaphragm 12 in a wider range and efficiently. It has a heat sink function for promoting the action, and is formed of a high thermal conductivity material as described above. In the present embodiment, the auxiliary diaphragm 11b is made of an aluminum material that is a high thermal conductivity material and can be reduced in weight.

In the example shown in FIG. 2, the auxiliary diaphragm 11b is provided with a large number of through holes 11c to reduce the weight of the auxiliary diaphragm 11b and prevent the frequency characteristics from being deteriorated in a high frequency range.
In order to prevent an adverse effect due to the natural resonance frequency, particularly a sharp drop in the output signal level at a specific frequency due to resonance, the auxiliary diaphragm 11b may be subjected to embossing, bending, or surface hardening treatment.

As can be seen from FIG. 3, the transducer body 11a includes a voice coil 1, a voice coil bobbin 3, a magnet (permanent magnet) 4, a pole piece 5, a yoke 6, a frame 7, a damper 8, and the like. (Refer to FIG. 7).
The transducer body 11a is vibrated through the subplate 10 and the auxiliary diaphragm 11b by inserting and fixing the end of the voice coil bobbin 3 in the cylindrical portion of the subplate 10 that is tightly bonded to the auxiliary diaphragm 11b. Attached to the plate 12.
In the illustrated example, the sub-plate 10 is tightly joined to the auxiliary diaphragm 11b at an annular portion on the outer peripheral side of the bottom surface, and the center portion of the bottom surface is cut out in a circular shape so that the pole piece 5 and the auxiliary diaphragm 11b are connected to each other. It is made to face directly.

Here, the voice coil 1 is wound around and fixed to the outer periphery of the cylindrical voice coil bobbin 3 in the vicinity of the end opposite to the auxiliary diaphragm 11b side.
The pole piece 5 is positioned in the bobbin 3 such that the outer peripheral surface thereof faces the inner peripheral surface of the voice coil 1 via the voice coil bobbin 3. The pole piece 5 is tightly joined to the magnet 4, and the magnet 4 is tightly joined to the bottom surface of the bottomed cylindrical yoke 6 on the side opposite to the side where the pole piece 5 is joined.
The inner peripheral surface of the opening side end of the yoke 6 is opposed to the outer peripheral surface of the pole piece 5 to form a magnetic gap 2.

  The frame 7 is made of resin and holds the yoke 6. The pole piece 5 is held at the above position via the yoke 6 and the magnet 4. A damper 8 is placed between the frame 7 and the voice coil bobbin 3, and the voice coil 1 swings relative to the pole piece 5 and the yoke 6 in the axial direction of the voice coil bobbin 3 (left and right direction in FIG. 3). (Vibration) is possible.

  The voice coil lead 9A connects between the voice coil 1 and the speaker input terminal 9B. In the example shown in FIG. 1, a speaker wire 9D having a male connector 9C at the tip is connected to the speaker input terminal 9B. Therefore, by attaching the male connector 9C to a female connector (not shown) that forms the output terminal of the amplifier 14, the audio current from the amplifier 14 is input to the voice coil 1 (transducer body 11a).

Next, the operation of such a flat speaker will be described.
In the flat speaker shown in FIG. 3, the magnetic circuit forms a closed circuit that reaches the magnetic gap 2 through the magnet 4 → the yoke 6 and reaches the magnetic pole 2 through the magnetic gap 2.
Now, when the audio current from the amplifier 14 (see FIG. 1) is input to the transducer body 11a, specifically, to the voice coil 1 in the magnetic gap 2 through the speaker input terminal 9B and the voice coil lead 9A, electromagnetic A driving force by force is generated in the voice coil 1.
The transducer body 11a transmits this driving force (vibration) to the diaphragm 12, and radiates sound corresponding to the audio current from the diaphragm 12.
The details of the mechanism from the sound current / sound conversion to the sound radiation in the flat speaker are omitted here, but there is no significant difference from that in a general flat speaker.

When such a flat speaker, more specifically, the transducer body 11a continues to operate, particularly for a long time or at a high output, the amount of heat generated from the voice coil 1 increases remarkably. There is a risk that the voice coil 1 may be destroyed by melting the insulating coating or adhesive of the voice coil 1 constituting 11a.
In this embodiment, the transducer main body 11a is attached to the diaphragm 12 via the planar auxiliary diaphragm 11b made of a high thermal conductivity material that is overlapped and closely bonded to the diaphragm 12. Therefore, the heat generated in the transducer main body 11a is not only circulated by the convection (arrow A) and radiation (arrow A) shown in FIG. 7 but also radiated from the auxiliary diaphragm 11b. Moreover, since the auxiliary diaphragm 11b is planar and is not included in the constituent elements of the transducer body 11a, the size and the like can be set relatively freely, and a sufficient heat radiation effect can be obtained (see FIG. 5).

Therefore, the heat generated from the voice coil 1 can be dissipated easily and effectively, and in the flat speaker transducer 11 (planar speaker), both high allowable input and high conversion efficiency can be achieved. In addition, the output of the transducer body 11a can be increased, and a flat speaker with a large output can be manufactured with one transducer body 11a.
Moreover, the planar auxiliary diaphragm 11b also has a function to transmit the vibration of the transducer body 11a to the diaphragm 12 in a wider range and efficiently, so that the cost effectiveness of all the functions of the auxiliary diaphragm 11b is extremely high. Get higher.

As described above, the auxiliary diaphragm 11b is preferably made of an aluminum material, but may of course be an aluminum alloy material.
In addition, the surface of the auxiliary diaphragm 11b may be embossed, bent, or hardened, and this can prevent a sharp drop in the output signal level at a specific frequency due to resonance. Further, an appropriate number and diameter of the through holes 11c may be formed in the auxiliary diaphragm 11b to reduce the weight or prevent the high frequency characteristics from being deteriorated.

The heat generated from the voice coil 1 is transmitted to the auxiliary diaphragm 11b by conduction, convection, and radiation, but the members forming the path, such as the voice coil bobbin 3 and the sub plate 10, also have a high thermal conductivity like the auxiliary diaphragm 11b. It is desirable to be formed of a material. In the present embodiment, the voice coil bobbin 3 and the sub plate 10 are made of an aluminum material that is lightweight and has a high thermal conductivity.
The structure related to the path of the generated heat from the voice coil 1 is also a structure that is transmitted to the auxiliary diaphragm 11b by efficient conduction, convection, and radiation as long as compatibility between high allowable input and high conversion efficiency is not hindered. It is desirable. For example, when the transducer main body 11a (subplate 10) is attached to the auxiliary diaphragm 11b or the auxiliary diaphragm 11b is attached to the diaphragm 12, the adhesive or double-sided adhesive tape used therefor is also used. It is desirable to select one having a high thermal conductivity.

  A flat speaker in which the transducer body 11a is attached to the diaphragm 12 with the auxiliary diaphragm 11b interposed can be used as a screen. Specifically, a screen function can be imparted by laminating or coating a resin that serves as a light shielding layer and a resin that serves as a light reflecting layer on at least one surface of the diaphragm 12. At this time, only the resin that becomes the light reflection layer may be laminated or coated. The resin serving as the light shielding layer can be provided with a shielding property by containing a black dye or pigment, such as carbon black. Moreover, the resin used as the light reflection layer can contain white pigments or dyes, for example, titanium oxide, glass powder, or the like to impart light reflectivity. As the above resin, the above-described polyvinyl chloride or the like can be used.

  Further, the above flat speaker can also be used as an advertisement banner. For example, an advertisement banner provided with an advertising function by laminating or coating resin on at least one surface of the diaphragm 12 as necessary, and drawing characters and drawings with paint, pigment-based ink, dye-based ink, etc. Can be created. In addition, when the diaphragm is made of a fiber structure, it is possible to draw letters and drawings on the fiber structure by dyeing or printing. As the resin, the aforementioned polyvinyl chloride or the like can be used.

In applications such as screens and advertisement banners described above, winding and unfolding can be freely performed by using a flexible material such as a film, a sheet, or a fiber structure as the diaphragm 12, so that it can be carried and stored. Is excellent. For this reason, the flat speaker using the flexible diaphragm 12, in particular, the flat speaker using the fiber structure for the diaphragm 12 can be used for a wide variety of applications.
Also, in applications such as screens, especially advertising banners, heat and music will continue to be played for a long time, and heat generation will be a problem. However, since the transducer of the present invention is excellent in heat dissipation, such problems are remarkably improved. The

It is a disassembled perspective view of one Embodiment of the planar speaker to which this invention was applied. Similarly, two views ((a) is a front view and (b) is a right side view). Similarly, it is an enlarged view of a right cross section. It is a table | surface which contrasts and shows the thermal conductivity of the typical metal material which can be used as an auxiliary | assistant diaphragm. It is a table for demonstrating the effect of the heat radiation by an auxiliary diaphragm. It is a graph which shows the effect of the heat radiation by an auxiliary diaphragm. It is a conceptual diagram which shows the mode of heat dissipation in the conventional flat speaker.

Explanation of symbols

1: voice coil, 2: magnetic gap, 3: voice coil bobbin, 4: magnet, 5: pole piece, 6: yoke, 7: frame, 8: damper, 9A: voice coil lead, 10: subplate, 11: transducer 11a: transducer body, 11b: auxiliary diaphragm, 12: diaphragm, 71: transducer.

Claims (8)

A planar speaker transducer including a planar diaphragm,
The transducer is
A transducer body and a planar auxiliary diaphragm made of a high thermal conductivity material;
The transducer for a flat speaker, wherein the transducer body is attached to the diaphragm with the auxiliary diaphragm interposed so that heat generated from the transducer body can be conducted.   The flat speaker transducer according to claim 1, wherein the high thermal conductivity material is a metal material, and is subjected to embossing, bending, or surface hardening treatment.   3. The flat speaker transducer according to claim 1, wherein a plurality of through holes are formed in the auxiliary diaphragm.   A flat speaker, wherein the flat speaker transducer according to any one of claims 1 to 3 is attached to a flat diaphragm.   The planar speaker according to claim 4, wherein the planar diaphragm has flexibility.   6. The flat speaker according to claim 4, wherein the flat diaphragm is made of a fiber structure.   The screen using the flat speaker of any one of Claims 4-6. An advertising banner using the flat speaker according to any one of claims 4 to 7.

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