JP4652882B2 - Thin speaker - Google Patents

Description

  The present invention relates to a thin speaker with low noise generation and high sound pressure.

  FIG. 20 shows an example of a conventional thin speaker. In this speaker, a plurality of bar magnets 52 are arranged in parallel on a yoke 50, and a vibration film 54 is arranged in parallel to the magnetic pole surface of these bar magnets 52, in a direction orthogonal to the magnetic field generated by the bar magnets 52. A plurality of coils 56 are arranged at positions facing the rod-shaped magnet 52 on the vibration film 54 so that a current can flow. Then, by applying an alternating current to each of these coils 56, a force in accordance with the Fleming's left-hand rule is generated between the coils 56 and a magnetic field parallel to the coils 56. As a result, the vibration film 54 vibrates in a direction orthogonal to the film surface, and the electric signal is converted into an acoustic signal.

  However, in the above thin speaker, the coil facing the rod-shaped magnet has an elongated rectangular shape, and most of the coil is disposed at a position facing the magnetic pole surface of the rod-shaped magnet. The force in the direction along the diaphragm surface is generated by the influence of the magnetic field perpendicular to the coil on the surface and the diaphragm is kinked to generate noise, and the degree of freedom when designing the speaker shape and coil impedance is small. There was a problem.

  Further, as an improvement on the problem of the speaker of FIG. 20, a thin speaker having the configuration of FIG. 21 shown in Patent Document 1 is proposed. In the speaker having this configuration, a plurality of magnets 62 are arranged in parallel to the vibration film 64 on the planar yoke 60 so that adjacent magnetic pole surfaces are different from each other. A plurality of spiral coils 66 are arranged in a plane so that the inner circumference of the spiral is located near the portion corresponding to the outer edge of the magnetic pole surface. The current in the same direction flows through a portion of the first coil adjacent to the second coil and a portion of the second coil adjacent to the first coil. In the figure, 68 indicates a damper.

  With the above configuration, the force that the coil receives from the magnetic field orthogonal to the diaphragm is reduced, noise generation is reduced, and the area of the coil orthogonal to the magnetic field parallel to the diaphragm is increased, resulting in acoustic conversion. The efficiency is improved, and the degree of freedom in designing the shape of the entire speaker is improved as compared with the speaker of FIG.

  However, all the above-mentioned speakers have the following problems. That is, since a plurality of magnets are arranged on one surface of the planar yoke, the polarities of adjacent magnets are different from each other, and the magnetic pole surface is parallel to the yoke, the horizontal direction as shown in FIG. Leakage magnetic flux is used as a driving force for framing. Therefore, as the vibration film vibrates, the distance between the vibration film arranged parallel to the magnetic pole surface and the magnetic pole surface changes, and the horizontal magnetic flux received by the vibration film changes greatly. Furthermore, the spiral coil formed on the vibrating membrane is also in a positional relationship parallel to the magnetic pole surface, and the driving force increases when approaching the magnetic pole surface with a strong magnetic flux, but the amplitude increases near the fo, and the vibrating membrane and magnet It becomes easy to generate abnormal noise. In addition, there is a problem in that low-frequency sound reproduction, which cannot withstand a large input due to a collision between the vibration film and the magnet or has a large amplitude, is limited.

  FIG. 23 is an example of a static magnetic field analysis for the magnet arrangement and the coil arrangement shown in FIG. 22 for explaining the above. FIG. 23 shows an example in which the coil is disposed on one side (lower surface) of the vibration film, but the same applies to the case where the coil is disposed on both surfaces of the vibration film. Furthermore, although the cross section of the coil is indicated by a round shape, the cross section of the coil may be square. The length of the vector represents the strength of the magnetic flux. In the model of FIG. 22, the horizontal magnetic flux contributes to the driving force, but the strongest region of the horizontal magnetic flux is in the vicinity of the outer edge of the magnetic pole surface (the upper surface of the magnet). Near the center of the magnet, the magnetic flux in the vertical direction is the main component, and the component of the horizontal magnetic flux increases as it approaches the outer edge of the magnetic pole surface. In order to further increase the sound pressure, it is necessary to increase the driving force by increasing the magnetic flux density by arranging a coil in a region close to the magnetic pole surface. However, when the coil is brought close to the magnetic pole surface, the vibration film and the magnet are likely to collide with each other, so there is a structural limit, and it becomes difficult to obtain a large sound pressure. In particular, since the amplitude increases as the playback band becomes lower, there is a limit to bass playback.

  On the other hand, as shown in FIG. 24, FIG. 25 and FIG. 26, Patent Document 2 discloses a vibration film 4 of a plane drive type speaker composed of a thin film body formed with a plurality of protruding vibration elements 4a. In the winding configuration of the voice coil 5 in which the voice coil 5 is sequentially wound and held in series in a desired number of turns from the vibration element 4a on one side on the outer surface of each vibration element 4a, the voice coil wound on each adjacent vibration element 4a 5, a voice coil winding configuration of a planar drive type speaker is disclosed, wherein the winding position of 5 is appropriately changed and the winding is arranged in a line in the groove between the vibration elements 4a.

  If the magnet and voice coil arrangement shown in FIG. 24 is used, it is possible to use a region having a large horizontal magnetic flux, which is more advantageous for sound pressure and bass reproduction than the magnet and voice coil arrangement shown in FIG. However, since the voice coil 5 is arranged in multiple layers in a row in the groove 4b on the outer surface of the vibration element 4a protruding vertically from the vibration film 4, the structure of the vibration film 4 becomes complicated, and the winding of the vibration element 4a is complicated. The manufacturing process is complicated and it is not suitable for mass production because it is necessary to perform a winding process, a separation process and a loading and bonding process of the voice coil using a shape substantially the same as the outer shape of the turning part. Further, since the vibration element 4a protrudes vertically from the vibration film 4, there is a problem in that the voice coil generates lateral vibration (chatter) in addition to the vertical vibration as shown in FIG. There is.

Japanese Patent No. 3159714 Japanese Examined Patent Publication No. 04-005319

  The present invention has been made in view of the above circumstances, and has a high degree of freedom in shape design and impedance design of the vibration membrane, and uses a vibration membrane with little impedance variation of the vibration membrane. An object of the present invention is to provide a thin speaker that ensures high sound quality and has both mass productivity.

According to the first aspect of the present invention, on the yoke having a flat portion, a plurality of magnets of the same size are arranged in a lattice shape so as to be spaced apart from each other by a predetermined distance and the magnetic pole surfaces of adjacent magnets are opposite to each other. The vibrating film is made of a thermoplastic resin having a pressure sensitive adhesive or an adhesive having a spiral coil arranged at a position corresponding to each of the magnetic pole faces and a predetermined distance from the magnetic pole face of the magnet. In a thin speaker, a linear conductor coated in advance with an insulation coating in the vicinity of a convex portion formed on the vibrating membrane at a position corresponding to the outer edge of the magnetic pole surface of the magnet is a non-planar three-dimensional coil with respect to the yoke. The vibrating membrane is further formed by forming the convex portion of the vibrating membrane by thermoforming in a temperature range above the glass point transition temperature of the thermoplastic resin and below the melting point. Form At the same time, the convex portion and the spiral three-dimensional shape of the coil is formed in a convex outer surface of the vibrating membrane integrally the insulating coated linear conductor formed in a spiral coil the vibrating membrane vibrating membrane It is characterized by being embedded between a resin layer having an adhesive or adhesive layer and another resin layer .

Shape of the convex portion for forming the quadrangular pyramid shape, a trapezoidal shape, U-shaped, cross-section is preferably such parabolic line shape, and has a configuration that does not hit the larger pole face also amplitude. As a result, since the voice coil can be arranged in a region having a high horizontal magnetic flux, a large driving force can be obtained and the sound pressure of the thin speaker is increased. In addition, a larger amplitude is possible compared to a planar diaphragm, input resistance is increased, and low-frequency reproduction is also possible. Furthermore, since no protrusion forming component is required for the formation of the vibration film protrusion, the vibration film can be reduced in weight and the sound pressure level can be improved.

2. The thin speaker according to claim 1, wherein the vibration film uses a thermoplastic resin as a base material, and has a convex portion formed by thermoforming in a temperature range not lower than the glass point transition temperature of the thermoplastic resin and not higher than the melting point. It is characterized by that. More specifically, a spiral conductor is formed by laying a linear conductor, which is pre-insulated, into a non-planar three-dimensional coil shape with respect to the yoke. Simultaneously with the formation of the convex portion, the convex portion of the vibrating membrane and the three-dimensional shape of the spiral coil are integrally formed on the outer surface of the convex portion of the vibrating membrane, and the linear conductor formed on the spiral coil is formed on the vibrating membrane. It is embedded between the resin layer having the pressure-sensitive adhesive or adhesive layer and another resin layer. As described above, a spiral conductor is three-dimensionally arranged on the outer surface of the convex portion formed on the vibrating membrane at a location corresponding to the outer edge portion of the magnetic pole surface of the magnet by embedding the linear conductor in the vibrating membrane. Therefore, high sound pressure and productivity can be improved.

The thermoplastic resin used for the thin speaker according to claim 1 includes polyethylene naphthalate (PEN), liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyether sulfone (PES), polyimide. Heat-resistant engineering plastics such as (PI), polyamideimide (PAI), polyetherimide (PEI), and aramid are preferred. This is because the voice coil is in direct contact with the diaphragm surface, and the Joule heat of the voice current is directly transmitted to the diaphragm. By adopting such a configuration, a member for forming the convex portion, an adhesive, or the like is unnecessary, and it is not necessary to increase the number of parts and increase the weight. Therefore, the vibration film can be reduced in weight, so that the mass productivity of a thin speaker with high sound pressure and improved low-frequency reproduction capability is improved. Since the bonding process is unnecessary, the production process can be simplified .

According to a second aspect of the present invention, in the thin speaker according to the first aspect, the three-dimensional shape of the spiral coil disposed in the vicinity of the convex portion of the vibrating membrane is the convex portion of the vibrating membrane or the vibrating membrane base. It is characterized by being formed by the same thermoforming as the formation of an edge made of a material or the formation of a rib for increasing the rigidity of the vibration film. Thus, the three-dimensional shape of the spiral coil disposed on the convex portion of the diaphragm is simultaneously formed by simultaneously molding the convex portion of the diaphragm, the rib and the speaker edge, thereby simplifying the manufacturing process. To improve productivity. By forming convex portions of the vibration film or using an edge made of the vibration film base material, the number of parts can be reduced and the mass productivity is excellent. By thermoforming at the same time as the ribs that increase the rigidity of the diaphragm, it is possible to increase the rigidity of the diaphragm without increasing the weight of the diaphragm, reducing distortion of the thin speaker and mass production of the thin speaker. Excellent.

The invention according to claim 3 is characterized in that the convex portion of the diaphragm is narrower and narrower at the tip of the convex portion than the bottom on the diaphragm side.

With the above configuration, there is an effect that the convex portion of the diaphragm is less likely to collide with the magnet, the generation of abnormal noise is eliminated, and the collision with the magnet due to the positional deviation during assembly of the diaphragm is suppressed. In addition, since the bottom portion of the convex portion on the vibration film side is wider than the tip portion, chatter and abnormal vibration due to rolling or the like do not occur during vibration, and generation of abnormal noise can be suppressed. Furthermore, since the tip of the convex part is narrower and narrower than the bottom part on the diaphragm side, the degree of freedom of the mold shape at the time of thermoforming is increased, and the diaphragm base material and the voice coil are not easily worn or cut. There is an effect of becoming.

  The shape of the convex part of the diaphragm includes a trapezoidal shape, a substantially triangular shape, a substantially semi-elliptical shape (bell shape), a semi-elliptical shape, a semi-circular shape, a substantially Gaussian curve shape (Western bell shape), and the like. Of these, trapezoidal, approximately semi-ellipse (bell shape), semi-ellipse, approximately Gaussian curve shape (Western bell shape), etc. are particularly suitable, and the cross-sectional shape of the convex portion is the height of the magnet, magnet spacing, amplitude, and vibration membrane base. The optimum shape is selected according to the thickness of the material.

According to a fourth aspect of the present invention, in the thin speaker according to any one of the first to third aspects, the vibration film is formed of a sheet-like base material having an adhesive layer on at least one surface, and is linearly coated in advance. The conductor is wired on the sheet-like substrate on the adhesive layer surface side.

  By adopting the above-described configuration, no bonding step is required when wiring the linear conductor, and high sound pressure and productivity can be achieved at the same time.

The invention according to claim 5 is the thin speaker according to claim 4 , wherein the adhesive layer of the sheet-like substrate is made of a silicon-based resin or an acrylic resin, and the sheet-like substrate on the adhesive layer surface side. In this case, after a linear conductor previously coated with an insulating coating is laid, the linear conductor is fixed to the convex portion of the vibration film with an epoxy resin.

  As described above, since the linear conductor is fixed to the convex portion of the vibration film with an epoxy resin, mass productivity for a complicated three-dimensional shape can be ensured. The epoxy resin may be heat-cured after being kept in a predetermined shape in a semi-cured state (B stage) where the shape can be easily changed.

According to a sixth aspect of the present invention, in the thin speaker according to any one of the first to fifth aspects, the vibrating membrane is a linear conductor that is pre-insulated with a semi-cured thermosetting resin at least on the convex portion of the vibrating membrane. The plurality of spiral coils are formed by fixing the coil in a coil shape.

With the above configuration, both high sound pressure and high reliability can be achieved.
The thermosetting resin may be completely cured by heating at a higher temperature after placing the coil in a state where the polyamic acid, which is a polyimide precursor, is semi-cured by heating. Polyamideimide resin, epoxy resin, unsaturated polyester resin, etc. are suitable for the thermosetting resin.

According to a seventh aspect of the present invention, in the thin speaker according to the first to sixth aspects, the base material of the vibration membrane is a resin foam.

  With the above configuration, the diaphragm base material can be realized with a light weight and high rigidity, and a thin speaker with high sound quality and low distortion can be realized.

The invention described in claim 8 is the thin speaker according to claim 7 , wherein the resin foam has an average cell diameter of 50 μm or less.

  By setting it as said structure, a thin foam with a thickness of 1 mm or less can be manufactured uniformly. When a substrate having the same weight per unit area of the resin film substrate and the resin foam is used for the vibration film, the apparent density of the foam decreases depending on the expansion ratio, and the thickness of the foam increases. As the thickness of the base material increases, the bending rigidity of the plate-like (or film-like) base material is proportional to the cube of the thickness. Bending vibration can be suppressed and distortion can be suppressed. In particular, the secondary distortion and the third distortion near the lowest resonance frequency fo having a large amplitude can be greatly suppressed. Furthermore, since the fine foam having an average cell diameter of 50 μm or less has innumerable bubbles inside, the internal loss (tan δ) of the base material is improved, the frequency characteristics are flattened, and the sound quality is improved. In particular, the clarity of the mid-high range is improved.

The invention according to claim 9 is the thin speaker according to claim 7 or 8 , wherein the resin foam is a resin foam sheet made of at least one thermoplastic polyester resin.

  With the above configuration, both high sound pressure and mass productivity can be achieved.

According to a tenth aspect of the present invention, in the thin speaker according to the first to ninth aspects, the linear conductor is an insulating coated conductor having at least one insulating layer on a surface layer thereof, and has a circular cross-sectional shape. , At least one of a square, a rectangle, and a flat plate.

  With the above configuration, the coil space factor can be freely selected, the coil selection range is improved even in a narrow space between magnets, and both high reliability in which sound pressure and abnormal noise are unlikely to be generated can be secured. .

An eleventh aspect of the present invention is the thin speaker according to the first to tenth aspects, wherein the linear conductor has a diameter of 0.02 mm to 0.4 mm.

  By adopting the above configuration, it is possible to cope with a thin speaker having a high range of sound pressure, a reproduction band, and a size. When the diameter of the linear conductor is 0.02 mm or less, the tensile strength of the wire is small, breakage occurs with a slight tension, and wiring at high speed becomes difficult. When the diameter of the linear conductor is 0.4 mm or more, the wire rod is difficult to bend, and it is difficult to form a highly accurate coil or to attach the coil to the wiring apparatus. Therefore, the above range in which the diameter of the linear conductor is 0.02 mm to 0.4 mm is excellent in the mass productivity of the wiring coil.

A twelfth aspect of the present invention is the thin speaker according to the first to eleventh aspects, wherein the linear conductor is a litz wire.

By using a litz wire for the linear conductor as in the above configuration, the linear conductor can be easily bent even if the conductor cross-sectional area is large, the wiring can be facilitated, and the weight of the coil can be increased. Can be increased. As a result, it is possible to form a thin speaker with high sound pressure. Litz wire has a nominal cross-sectional area of mm ² (number of component wires / wire diameter mm) of 0.01 (4 / 0.07), 0.02 (5 / 0.07), 0.025 (7 / 0.07), 0.03 (8 / 0.07), Various cross-sectional areas such as 0.035 (7 / 0.08), 0.04 (8 / 0.08), 0.05 (10 / 0.08), 0.10 (20 / 0.08), the number of strands, and the wire diameter can be selected to improve design flexibility. .

The invention according to claim 13 is the thin speaker according to claims 1 to 12 , wherein the conductor of the linear conductor is copper, copper alloy, aluminum, aluminum alloy, copper clad aluminum, copper clad aluminum alloy, copper plated aluminum, It includes at least one of copper-plated aluminum alloys.

  With the above configuration, an optimal wire can be selected as the conductor material of the linear conductor, so that both sound pressure and productivity can be achieved. With regard to the material of the linear conductor, increasing the composition ratio of copper to aluminum to reduce the weight of the coil can reduce the weight of the diaphragm and improve the sound pressure of a thin speaker even if the same magnetic circuit is used. Is possible. Furthermore, when soldering the linear conductor and the tinsel wire or the terminal, it is possible to improve the degree of freedom in selecting the solder material, such as avoiding the soldering of different metals, thereby improving the productivity. .

The invention according to claim 14 is the thin speaker according to any one of claims 1 to 13 , wherein the base material of the vibration membrane is a heat resistant film or adhesive layer having an adhesive layer on the surface on which the linear conductor is wired. It is a foam of a heat resistant resin having

  By setting it as said structure, a coil can be wired directly to a diaphragm base material, and it is excellent in mass-productivity. And even if the Joule heat of the current flowing through the coil is directly conducted to the diaphragm base material, it is not thermally destroyed, and a highly reliable thin speaker can be formed.

  As heat resistant resins, polyethylene naphthalate (PEN), liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyether sulfone (PES), polyimide (PI), polyamideimide (PAI), Engineering plastics such as polyetherimide (PEI) and aramid are preferred.

According to a fifteenth aspect of the present invention, in the thin speaker according to the fourteenth aspect , the adhesive layer of the base material of the vibration film is made of at least one of an acrylic resin, a silicon resin, and an epoxy resin, and is insulation-coated. The present invention is characterized in that a linear conductor is directly wired.

  By adopting the above configuration, heat resistance is improved while ensuring the flexibility of the adhesive layer, the strain at the time of thermoforming is absorbed by the slip of the adhesive layer, and mass molding of the diaphragm and coil can be applied. Excellent in reliability and reliability.

The invention according to claim 16 is the thin speaker according to any one of claims 1 to 15 , wherein the linear conductor and the terminal wired on the vibrating membrane are connected to a flexible wire (kink wire, stranded wire, braided wire). It is characterized by being soldered via.

  With the above configuration, mass productivity and high reliability can be obtained with respect to mechanical and electrical joining.

According to a seventeenth aspect of the present invention, in the thin speaker according to the first to sixteenth aspects, a linear conductor wired to the vibrating membrane and a lead wire (kinshi wire, stranded wire, braided wire) are connected by solder, The connection location is covered with a resin.

  By setting it as said structure, the corrosion prevention of the metal (copper, aluminum) of a linear conductor, moisture prevention, and insulation reliability improve.

  According to the thin speaker according to the present invention, a plurality of magnets are arranged on a yoke having a flat portion at a predetermined distance so that the magnetic pole surfaces of adjacent magnets are opposite to each other. In a thin speaker constituted by a vibrating membrane that maintains a predetermined distance from the magnetic pole surface and has coils arranged at locations corresponding to the magnetic pole surface, the vibrating membrane is molded at the location corresponding to the outer edge of the magnetic pole surface of the magnet. Since the linear conductor is laid out in the vicinity of the convex portion in a non-planar coil shape with respect to the yoke, the coil can be formed in a region where the magnetic flux density is high, so that the sound pressure is high. Since the voice coil is not formed by etching but uses a linear conductor, there is little variation in impedance.

  In addition, since the vibration film is continuously formed in a curved surface from the high magnetic flux density region to the low magnetic flux density region, chatter of the voice coil is difficult to occur and the vibration film and the magnet do not collide with each other. The input resistance is large. In addition, since a large amplitude can be secured, the bass reproduction band is wide.

  In order to explain the thin speaker according to the present invention in an easy-to-understand manner, FIG. 1 is a cross-sectional view in which the positional relationship between the magnetic pole surface and the vibrating membrane 4 is the same as in FIG. As shown in FIG. 1, the thin speaker has a plurality of magnets 2 arranged at a predetermined distance so that the magnetic pole surfaces of adjacent magnets 2 are opposite to each other, and the outer edge of the magnetic pole surface of the magnet 2. The vibration film 4 in which the voice coil 5 is formed and the magnet 2 are arranged in a portion corresponding to the frame 1, the frame 1 also serving as a yoke, the sound emission hole 3 for adjusting the back pressure on the frame 1, and the distance between the vibration film 4 and the magnetic pole surface are vibrated. The edge 9 is kept constant in a possible state.

  The voice coil 5 receives the leakage magnetic flux from the magnet 2 in which N poles and S poles are alternately arranged from the direction perpendicular to the flow of current to generate framing driving force, and the diaphragm 4 is in the thickness direction of the diaphragm. Vibrates to generate sound pressure. The voice coil 5 is spirally formed on the surface of the vibrating membrane 4 at a portion corresponding to the outer edge of the magnetic pole surface of the magnet 2 so that the horizontal magnetic flux density received by the voice coil 5 is as large as possible.

  The driving force for framing increases in proportion to the current flowing through the voice coil 5, the length of the coil, and the magnetic flux density intersecting the voice coil 5 at a right angle. In order to increase the sound pressure, the distance (gap) between the vibrating membrane 4 and the magnet 2 may be reduced to increase the magnetic flux density. However, the vibrating membrane 4 and the magnet 2 collide with each other, and abnormal noise is likely to occur. In particular, at frequencies near the lowest resonance frequency fo, the amplitude becomes large and a collision is likely to occur. In order to avoid the collision, it may be necessary to limit the input resistance and the bass reproduction band.

  The present invention relates to a thin speaker in which sound pressure is improved by using a high magnetic flux, and generation of abnormal noise due to a collision between the magnetic pole surface and the vibration film 4 is compatible. As shown in FIG. 2, a projection (convex portion 10) is provided on the vibration film 4 at a portion corresponding to the outer edge portion of the magnetic pole surface of the magnet 2, and in the vicinity of the convex portion 10 formed in a non-planar coil shape with respect to the yoke. By providing the wired voice coil 5, the voice coil 5 is arranged in a region having a high magnetic flux density. In order to prevent the vibration film 4 and the magnet 2 from colliding with each other even when the amplitude increases with vibration, the vibration film 4 is arranged three-dimensionally, that is, the arranged coil is non-planar with respect to the yoke. It is characterized in that a convex part is formed on. Further, by providing the vibration film 4 with the convex portion 10, the surface area of the vibration film 4 is increased, and even if the impedance is the same, a linear conductor having a large conductor cross-sectional area is used, and the length of the coil is reduced. Therefore, the driving force of framing increases and the sound pressure increases.

  There are two reasons why the sound pressure is increased by the present invention. The first reason is that the voice coil 5 is disposed in the vicinity of the convex portion 10 of the vibration film 4 and disposed in a region where the horizontal magnetic flux is close to the magnetic pole surface so that the vibration film 4 and the magnet 2 do not collide with each other. It is. The second reason is that, compared with the conventional coil arranged on the horizontally flat vibrating membrane 4 to supplement the horizontal magnetic flux, the present invention is a coil formed at a portion where the convex portion 10 is formed three-dimensionally in a desired shape. This is because the surface area of the vibrating membrane 4 is increased and a long coil can be disposed. Since the driving force F of framing is F = (audio current i) × (magnetic flux density B) × (coil length L), the above reason is due to an independent cause. That is, the first reason is to increase the magnetic flux density B, and the second reason is to set the coil length longer. Further, when the surface area of the coil portion of the vibration film 4 is increased, the heat dissipation efficiency of Joule heat generated from the audio current is increased, and the input resistance can be set large. The above is schematically described as follows.

  For convenience of explanation, a conventional model will be described with reference to FIG. This is referred to as a conventional model 1. 20, 21, 22, 23, and 1 are the same as those of the conventional model 1 with respect to the positional relationship between the coil disposed on the diaphragm 4 and the magnet 2, and the coil is disposed on one or both sides of the diaphragm 4. Regardless of this, the common point is that the magnetic pole surface and the coil surface are substantially flat and parallel. The problem with the conventional model 1 is that since the position of the coil is far from the magnetic pole surface, the horizontal magnetic flux density received by the coil is lower than that near the magnetic pole surface, a large driving force cannot be obtained, and the sound pressure is low. If the gap between the vibrating membrane 4 and the magnetic pole surface is reduced in order to increase the sound pressure, the vibrating membrane 4 and the magnet 2 collide with each other, and abnormal noise is likely to occur. In addition, there is a problem that reproduction in a low range where the amplitude increases becomes difficult, and the input resistance cannot be increased.

  A conventional model corresponding to FIGS. 24, 25, 26, and 27 will be described with reference to FIG. This is referred to as the conventional model 2. In the conventional model 2, the coils are wound in a line in the vibration direction of the vibration film 4, and the coil can be disposed in the vicinity of the magnetic pole surface having a high horizontal magnetic flux density, and the sound pressure is higher than in the conventional model 1. . However, since the coils arranged in a line in the vertical direction vibrate vigorously in the vertical direction, there is a problem that distortion and abnormal noise due to the rolling of the coil are likely to occur.

  As a model obtained by improving the conventional model 2, there is a conventional model 3. The conventional model 3 will be described with reference to FIG. That is, in the conventional model 3, a coil is wound around a coil holding part that has a direction coinciding with the vibration direction of the diaphragm 4, and it is possible to generate a larger driving force than in the conventional models 1 and 2. is there. However, there is a problem that the weight of the additional coil holding component 11 increases and the sound pressure cannot be increased effectively. Furthermore, in order to form the coil holding component 11 perpendicularly to the vibration film 4, bonding is generally used, but it is difficult to reduce the thickness with a thin wall, and it is also difficult to form the coil at a low cost. .

  The present invention solves the problems of the conventional models 1, 2, and 3. The basic model of the present invention is referred to as the present invention model 1 and will be described with reference to FIG. That is, in the model 1 of the present invention, a plurality of magnets 2 are arranged on a yoke having a flat portion at a predetermined distance so that the magnetic pole surfaces of adjacent magnets 2 are opposite to each other. A vibrating membrane 4 in which a coil is disposed at a position corresponding to the outer edge portion of the magnetic pole surface is disposed at a predetermined distance from the magnetic pole surface of the disposed magnet 2. The vibration film 4 is formed with a convex portion 10 at a portion corresponding to the outer edge portion of the magnetic pole surface of the magnet 2, and in the vicinity of the convex portion 10, the linear conductor is wired in a non-planar coil shape with respect to the yoke. is doing.

For example, when the magnet arrangement is 3 columns × 5 rows (15 pieces), the vicinity of the sides of the quadrangle constituting the magnetic pole surface of all the magnets is spirally formed as shown in FIG. In the case of forming a coil, the coil may be partially formed in a spiral shape as shown in FIG. The coil does not form a spiral loop. For example, as a reference example , a coil having a staircase shape or a meandering shape (part of FIG. 10C) is shown. Stepped shapes and meandering (meandering) shapes (part of FIG. 10C) are not included in the present invention. As for the winding method of the coil, if the current flowing direction and the horizontal magnetic field direction always maintain a constant relationship, the direction of the driving force of the framing generated in the linear conductor can be matched to avoid the cancellation of vibration. The direction of the current flowing through the coil is disclosed in Patent Document 1 and Patent Document 2.

  In the model 1 of the present invention, since the coil is disposed in the vicinity of the convex portion 10 of the vibration film 4, it becomes possible to use a region having a higher horizontal magnetic flux density as shown in FIG. A driving force is obtained and a coil holding part is unnecessary, so that the weight is not increased and the sound pressure is increased. Moreover, since the convex part 10 of the vibration film 4 has a thin tip, even if vertical vibration is applied to the coil, generation of abnormal noise due to rolling or the like is suppressed. By devising the shape of the convex portion 10, it is possible to increase the amplitude by avoiding the collision of the vibration film 4 and the magnet 2, and it is possible to widen the bass reproduction band and increase the input resistance. It becomes. Further, since the tip of the convex portion 10 is thin, the vibration film 4 is sandwiched between convex and concave molds, and thermoforming is performed, so that there is an effect of excellent mass productivity.

  On the other hand, what formed the convex part 10 of the vibration film 4 not by shaping | molding but adhesion | attachment of the protrusion component 11, etc. was shown in FIG.6 (b) as a comparative model. Even in the comparative model, the same framing driving force as that of the model 1 of the present invention shown in FIG. 6A can be obtained, but the weight of the protruding parts 11 and the weight of the adhesive are excessive. There is a problem that the sound pressure cannot be raised sufficiently.

  As the shape of the convex portion 10 of the vibration film 4, a semicircular or semi-elliptical shape as shown in FIG. In the present invention model 3 as shown in FIG. 8A, the tip of the convex portion 10 is narrowed, and the shape of the convex portion 10 becomes wider as the horizontal portion of the vibrating membrane 4 is approached. The same effects as those of invention models 1 and 2 can be obtained. The shape of the convex portion 10 of the vibration film 4 can be selected as appropriate depending on the thickness of the vibration film 4, the distance between the magnets 2, the coil diameter, the gap between the magnetic pole surface and the vibration film 4, and the like. Since the tip of the convex portion 10 of the present invention model 3 is thin, even when the tip of the coil swings downward from the height of the magnetic pole surface, there is a feature that the coil and the magnet 2 do not easily collide with each other. Has the manufacturing advantage of becoming rough.

  As shown in FIG. 2, the voice coil 5 is provided with a protrusion (convex portion 10) on the vibration film 4, and is arranged in a non-planar coil shape with respect to the yoke in the vicinity of the convex portion 10 formed. ing. Further, it is desirable that the vibration film 4 is made of a thermoplastic material so that it can be thermoformed. When a material having thermoplasticity is used as the base material of the vibration film 4, the base material is an insulating base film. The voice coil 5 is formed not only on one side of the insulating base film (in FIG. 2, the crest or trough of the convex portion 10) but also on both sides (in FIG. 2, both the crest and trough of the convex portion 10). May be.

Furthermore, the voice coil 5 may be wired to the bottom of the convex portion 10 of the vibration film 4 or a part of the flat portion of the vibration film 4.
In the model 4 of the present invention, a spiral coil is formed only on the convex portion of the vibration film 4 as shown in FIG. In this model, a coil can be arranged near the height of the upper surface of the magnet 2 having the highest horizontal magnetic flux density. However, if the interval between the adjacent magnets 2 becomes too wide, the magnetic flux density is reduced. FIG. 8C shows a plate 21 disposed on the upper surface of the magnet 2, and the distribution of magnetic flux can be adjusted.

  For the purpose of ensuring the rigidity of the diaphragm 4, as shown in FIG. 8D, a rib 41 is provided on a flat portion where the voice coil 5 is not disposed, or a gentle curved surface is formed by eliminating the flat portion. Also good. Furthermore, it is possible to control the stiffness of the diaphragm by changing the shape of the ribs or providing a gentle curved surface on the flat part of the diaphragm, and control fo without increasing the weight of the diaphragm. I can do it. Furthermore, a fixed edge (9 in FIG. 8 (d)) in which the edge 9 is integrated with the vibrating membrane base material can be formed by thermoforming the vibrating membrane 4 using a thermoplastic resin as a base material. Thus, if the edge 9 and the rib 41 are integrally formed with the three-dimensional coil, the mass productivity is dramatically improved.

  FIG. 8E shows an example in which ribs 41 are provided on the outer periphery of the vibration film. The rigidity of the vibration film is greatly influenced by the material properties of the sheet base material 12 and the pressing film 13 constituting the vibration film, particularly the Young's modulus and the thickness of the material. If the thickness of the sheet base material 12 and the pressing film 13 constituting the vibration film is excessively thin, the rigidity of the vibration film may be insufficient and distortion may be increased in the vicinity of the fo. By providing the rib 41 on the outer peripheral part or the flat part, it is possible to increase the rigidity of the vibration film without increasing the weight of the vibration film. As described above, the three-dimensional coil and the integral thermoforming of the diaphragm allow the fo to be controlled and the distortion to be reduced without causing a drop in sound pressure by appropriately selecting the position and shape of the rib 41. I can do it.

  FIGS. 15 to 17 (a) and (b) show a method of fixing a lead wire for electrically joining a linear conductor and a terminal wired on a vibration membrane. The lead wire is made of tinsel wire, stranded wire or braided wire so as not to break against vibration, and the material is copper, copper alloy, aluminum, aluminum alloy, copper clad aluminum, copper clad aluminum alloy, copper plated aluminum, copper plated An aluminum alloy or the like is used.

  The voice coil 5 made of a linear conductor is joined to a lead wire (mainly tinsel wire 17) and a solder 19, and the entire joint is completely covered with a resin 18 such as an adhesive, so that a metal (copper, aluminum) is made. Corrosion prevention and insulation reliability can be ensured. Moreover, by covering the solder 19 joint with the resin 18, there is an effect of reducing the influence of vibration and preventing disconnection due to metal fatigue.

  FIG. 15A is a top view of a state in which the overlapping portion of the voice coil 5 and the tinsel wire 17 is joined with the solder 19, and the entire solder joint is covered with the resin 18, and FIG. A cross-sectional view including the film 4 is shown. FIG. 16A is a top view in the case where soldering is performed using the copper foil 20 in order to improve the workability and reliability of the solder 19 bonding, and FIG. 16B is a cross-sectional view thereof. Further, FIG. 17A is a cross-sectional view of a state in which the voice coil 5 is entangled with the tinsel wire 17 and the entangled portion is joined by the solder 19. Instead of being partially covered with the resin 18 such as an adhesive, the solder 19 joint may be embedded between the sheet base 12 with the pressing film 13 or the adhesive 16 constituting the vibration film.

  FIG. 17B is a top view showing the positional relationship between the solder 19 joint portion and the entire diaphragm, and the voice coil 5 produced in order to ensure the solder joint workability of the voice coil 5 and the tinsel wire 17. This is an example in which a loop 22 is formed in the voice coil 5 as the extra length processing. The top view of the vibrating membrane in FIG. 10B is an example when soldering is performed using the copper foil 20 as shown in FIGS. 16A and 16B.

Example 1
Neodymium magnets 2 having a width of 7 mm, a length of 7 mm, and a thickness of 2.5 mm are arranged in 2 columns × 4 rows (8 pieces) on a flat yoke made of soft iron (SPCC) having a thickness of 0.8 mm, and face the magnets 2. A thin speaker was created by arranging the vibrating membrane 4 at a position (see FIG. 2). The external size of the thin speaker is 40 mm × 78 mm × thickness 8 mm. The frame 1 and the yoke are integrally processed by soft iron press molding, and a sound emission hole 3 of φ4 mm is provided between the magnet 2 and the magnet 2 on the yoke. It was.

  The vibration film 4 is made of a heat-resistant PEN film having a thickness of 25 μm (manufactured by Teijin DuPont, Q83-25) as a sheet base 12 and an adhesive made of a silicone resin (DKQ9-9001 made by Dow Corning Asia) on its surface. It was applied, and a copper clad aluminum wire was wired as a linear conductor on the surface of the sheet substrate 12 on the side where the adhesive was applied.

  When wiring a linear conductor, a wiring device disclosed in Japanese Patent Laid-Open No. 2001-126942 is used. And by the said apparatus, a linear conductor is wired to the sheet | seat base material 12, and the coil pattern of the two-dimensional spiral-shaped voice coil 5 is formed (refer Fig.9 (a)). As the linear conductor used for the wiring, a wire rod having a circular cross-sectional shape of 0.21 mm in diameter, in which a core wire made of a copper clad aluminum wire having a conductor diameter of 0.19 mm was covered with a polyurethane resin insulator, was used. As the vibration film substrate, a heat-resistant foam with an adhesive coated with a silicon adhesive was used as the vibration film substrate. As the heat-resistant foam, a PEN sheet having an average cell diameter of 10 μm or less and a double foam (made by Furukawa Electric Co., Ltd., ultra-fine foam sheet) having a thickness of 0.2 mm was used. FIG. 12 shows a cross-sectional photograph of a PEN foam composed of closed cells. The vibration membrane is made by laminating by vacuum thermocompression bonding with a silicon adhesive surface of a sheet base material made of PEN film pre-wired with a linear conductor on a vibration membrane base material made of foam with adhesive. did. As a method for producing a vibration membrane, the above shows a method of arranging a linear conductor on a PEN film substrate. However, a linear conductor is arranged on a PEN foam with a silicone adhesive (see FIG. 9A). Then, a PEN film with a silicon adhesive may be bonded and deaerated and adhered by a vacuum press (see FIG. 9B).

  Here, the top view of the sheet | seat base material 12 in which the coil pattern was formed was shown in FIG. In FIG. 10A, among the plurality of formed coils, each coil has a spiral shape. The optimum number of spirals can be selected according to the conductor cross-sectional area, impedance, diaphragm area, and number of coils of the linear conductor. And each coil is electrically connected by the meandering linear conductor. In FIG. 10 (a), the position of the meandering linear conductor connecting between some coils (for example, b, c, and e, f in FIG. 10 (a) pass through the central portion of the coil. Is for easy understanding of the direction of current flow in each coil by arrows, and is actually wired adjacent to the corresponding spiral.The unit of Comparative Example 1 corresponding to FIG. A flat vibration membrane is formed with a roll edge (reference numeral 9 in FIG. 1) made of urethane foam (DZ-X made by Bridgestone), and a predetermined gap with a neodymium magnet (made by NEOMAX) which is a magnet (reference numeral 2 in FIG. 1). Secured and assembled to the frame (reference numeral 1 in FIG. 2) with an adhesive.

  Next, the manufacturing method of the diaphragm (symbol 10 in FIG. 2) having the convex portions of the example will be described. When the vibration membrane having the above-described configuration is schematically shown, as shown in FIG. 13, the linear conductor to be the voice coil 5 is sandwiched between the PEN film and the PEN foam each having the silicon adhesive 16 having a thickness of 50 μm. Are stacked. The sheet base material 12 with an adhesive for laying the linear conductor may be either a PEN film or a PEN foam, and if it is deaerated and adhered by a vacuum press, the PEN film or the PEN foam may be wired. In both cases, adhesion can be ensured as shown in FIG. The condition for forming the convex portion on the vibration film is that the temperature of the mold 14 having a glass transition point temperature (Tg = 116 ° C.) or more and a melting point (mp = 266 to 273 ° C.) of PEN which is a thermoplastic resin is 200 ° C. The test was performed in 5 seconds (FIG. 9 (c)).

  In this way, the protrusion (convex portion 10) is formed on the vibrating membrane 4 by the above-described thermoforming (FIG. 9D), and the cloth is formed in a coil shape that is non-planar with respect to the yoke in the vicinity where the convex portion 10 is formed. A wired voice coil 5 is provided. The maximum height of the convex portion was 1.5 mm, and the vibration membrane described in 10 of FIG. 2 was produced, and the unit of the example was created using a roll edge made of urethane foam. As shown in FIG. 11, the linear conductor wired on the coil was disposed at a position corresponding to the outer edge portion of the magnetic pole surface of the magnet where the current flowing through the coil and the horizontal magnetic flux density are orthogonal to each other as much as possible. The number of turns of the coil depends on the cross-sectional area of the linear conductor, the impedance, the vibration membrane area, the number of coils, the coil weight, and the reproduction band that is closely related to the amplitude, so the inner periphery of the spiral coil You may arrange | position in the position which the part containing an inner side from the peripheral part of opposes.

  Here, both ends of one linear conductor (voice coil 5) wired on the vibration film 4 are soldered to a flexible wire (in this embodiment, a tinsel wire 17). The soldered portion is covered with a resin 18 (adhesive DB1600B) having the purpose of insulation and moisture prevention (see FIG. 15). In the following example, as in Example 1, both ends of the linear conductor are soldered to the tinsel wire, and the soldered part is completely covered with resin.

  The sound pressure frequency characteristic was measured in the range of 20 Hz to 20 kHz using an ASA-2 system manufactured by Etani Electric Co., Ltd. with the unit mounted on a standard baffle defined in JIS C5532. The result is shown in FIG. Although a flat frequency characteristic was obtained over the entire frequency, the average sound pressure in the example increased by about 6 dB compared to the comparative example. The diaphragm area and diaphragm weight of Example 1a and Comparative Example 1a are the same, and since the same magnet arrangement and number (2 × 4 arrangement) of magnetic circuits are used, the sound pressure of Example 1a is large. This is because, as shown in FIG. 2, the voice coil is arranged on the convex portion of the diaphragm, so that the horizontal magnetic flux density of Example 1a is larger than that of Comparative Example 1a, and the driving force is increased.

(Example 2)
The same silicon adhesive as in Example 1 was used as the base material to be wired, and the case of wiring to the PEN film (pressing film 13) and the case of wiring to the PEN foam base material (sheet base material 12) The composite was thermoformed by various methods (see FIG. 9C). There are vacuum forming method, pressure forming method, and match forming method as thermoforming means, and when performed under standard conditions, the sound pressure frequency characteristics are independent of the conditions of the substrate to be wired and the means of thermoforming. The same results as in Example 1a described in Example 1 were obtained.

  Vacuum forming methods include straight forming, drape method, plug assist method, plug assist reverse draw method, and air slip method. There are two types of pressure forming methods: vacuum / pressure forming and pressure forming. The match forming method includes various methods derived from a mold heating / cooling method and a film heating (preheating) method. In any method, if the voice coil portion of the vibration film is molded into a convex portion using a mold at a temperature not lower than the glass transition point temperature of the thermoplastic resin and not higher than the melting point, an effect of increasing sound pressure can be obtained.

(Reference Example 1)
Example 1 in which a release paper was bonded after a 50 μm thick acrylic adhesive (Toyo Ink Co., Ltd., Double Face R390) was bonded to a 0.5 mm thick PEN foam (sheet substrate 12). The convex part 10 having the shape shown in FIG. 19A was formed under the vacuum pressing conditions. The release paper was peeled off in a state where the convex portion 10 of FIG. 19B was formed, and fixed to the male mold so that the acrylic adhesive faced up (downward) in the state of FIG. 19C. On the other hand, the acrylic adhesive was bonded to a PEN film (sheet 15) having a thickness of 25 μm, and a 2 × 4 voice coil 5 was wired using the same copper clad aluminum wire as in Example 1. It fixed to the female metal mold | die of FIG.19 (c) so that the surface of the acrylic adhesive of the PEN film in which the voice coil 5 was formed may become an upper surface. As shown in FIG. 19 (c), the wired voice coil is opposed to the protruding portion of the PEN foam, and depressurized and attached by a vacuum press at a mold temperature of 130 ° C. (FIG. 19 (d)). Was made.

The diaphragm of Reference Example 1 (FIG. 19 (d)) has the same outer size as the diaphragm of Example 1 (FIG. 9 (d)), and the thickness is the same only in the difference between silicone and acrylic. The total weight of the vibrating membrane is almost the same. A unit was assembled using the vibrating membrane adhered with the acrylic adhesive of Example 3. When the sound pressure frequency characteristics of the unit of Example 3 were measured under the conditions described in Example 1, almost the same sound pressure frequency characteristics as in Example 1 were obtained, and the average sound pressure was higher than that of the conventional example described in Example 1. Was about 6 dB higher.

Regarding the selection of the pressure-sensitive adhesive of Reference Example 1, a general acrylic pressure-sensitive adhesive is usually used, and when a high input resistance is required, a silicon pressure-sensitive adhesive having a high thermal stability may be selected. In addition to the above-mentioned DKQ9-9001 made by Dow Corning Asia, in order to secure further heat resistance, for example, when SD4560 or SD4580 made by Toray Dow Corning Silicone is selected, the voice coil temperature is 140 ° C to 180 ° C. A stable adhesive force can be secured even when the temperature is high.

( Reference Example 2 )
With respect to the formation of the vibration film protrusion, a protrusion part having a height of 1.2 mm was prepared and bonded to a PEN foam substrate having a thickness of 0.5 mm with an adhesive. The rectangular shape shown in FIG. 5 and the trapezoidal protruding component shown in FIG. 6B ( Reference Example 2 (b)) were respectively cut out from a glass epoxy substrate having a thickness of 1.2 mm into a cross-beam shape. The bonding of the voice coil was performed under the conditions described in Example 2, and a unit was produced in the same manner as in Example 1 and the sound pressure frequency characteristics were measured. As a result, the model of FIG. 5 ( Reference Example 2 (a)) and the model of FIG. 6 (b) ( Reference Example 2 (b)) show almost the same frequency characteristics as the comparative example of Example 1, and the sound pressure rises. Could not be confirmed. Regarding the vibration membrane, the model of FIG. 5 ( Reference Example 2 (a)) and the model of FIG. 6 (b) ( Reference Example 2 (b)) are the same as those of FIG. 9D and FIG. 19D of Reference Example 1 . From the model, the weight of the vibration film increased by the amount of the protruding parts and the adhesive, and the weight of the vibration film almost doubled.

(Reference Example 3 )
The protrusion-shaped material used in Reference Example 2 is switched from a glass epoxy substrate to a PEN foam and a polypropylene (PP) foam (Fcel, manufactured by Furukawa Electric Co., Ltd.) to reduce the weight, and the shape size is the same. Evaluation was performed. The bonding of the voice coil was performed under the conditions described in Example 2, and a unit was produced in the same manner as in Example 1 and the sound pressure frequency characteristics were measured. As a result, the frequency characteristics of almost the same pattern as Example 1 of the present application were shown in all frequency bands, but the average sound pressure was about 4 dB lower than Example 1 of the present application and about 2 dB higher than the comparative example of Example 1. It was. This is because the protruding parts made of PEN foam and PP foam are both about 1/4 lighter than the protruding parts made of glass epoxy board, so the protruding parts of glass epoxy board were used. This is about 2 dB higher than the sound pressure of the thin speaker unit. When using protruding parts in this way, the weight of the adhesive used to fix the protruding parts to the diaphragm is not negligible even if foam is used to reduce the weight of the parts. The improvement is limited.

  Further, when 15 W was input in the input resistance test, no abnormality was found in the protruding parts of the PEN foam, but the vibration film using the protruding parts of the PP foam was deformed. When the cross section of the deformed protrusion portion was observed with a microscope, it was found that a part of the PP foam was melted and the bubbles of the foam were crushed. When confirmed by using a polyethylene (PE) foam (Furukawa Electric Co., Ltd., Foam Ace) instead of the PP foam, an abnormality occurred in the 15 W input resistance test as with the PP foam. It has been found that since the Joule heat generated when a current flows through the voice coil is directly transmitted to the projecting part, it cannot withstand the heat resistance level of PP or PE.

  Since the Joule heat from the voice coil is directly transmitted to the diaphragm base, the material of the diaphragm base was also confirmed by experiments. Prototypes of diaphragm base materials were made using various resins. As a result, the diaphragm base material is polyethylene naphthalate (PEN), liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyether sulfone (PES) regardless of the shape of the film or foam. ), Polyimide (PI), polyamide imide (PAI), polyether imide (PEI), aramid, epoxy resin and other heat resistant engineering plastics were used, it was confirmed that deformation and dissolution due to heat could be avoided. However, since PI and epoxy resin are cured by heating, a film-shaped resin base material in a semi-cured state (B stage) is used when forming into a predetermined shape by thermoforming. Of course, the heat resistance of the substrate basically depends on the physical properties of the resin material itself, and in addition to films and foams, the diaphragm substrate is excellent in heat resistance even if the form changes, such as unemployed cloth or cloth. The material is preferable, and the higher the heat resistance, the higher the input resistance tends to be.

(Example 3 )
In the process of Example 1, the shape of the protrusions was changed to a substantially elliptical shape in FIG. 7 and an inverse Gaussian distribution shape in FIG. The sound pressure frequency characteristics were measured under the conditions described in Example 1. As a result, the sound pressure frequency characteristics of the embodiment in which the protrusion shape of the vibration film is substantially elliptical (FIG. 7) and the embodiment having the inverse Gaussian distribution shape (FIG. 8A) are the same as those in the embodiment 1 (FIG. 9). (D), almost the same results as in FIG. 6 (a)) were shown, and the average sound pressure was about 6 dB higher than that of Comparative Example 1. With respect to the shape of the projection of the diaphragm, if the tip is thinner than the bottom near the diaphragm, collision with the magnet can be avoided, and the degree of freedom in design is increased with respect to positional deviation tolerance when the unit is assembled. In addition, by providing a slope that makes the tip narrow on the side surface of the projection of the diaphragm, the rate of dimensional change on the diaphragm substrate and voice coil during thermoforming can be suppressed, and the voice coil can be rubbed or cut. Can be avoided.

(Example 4 )
Regarding the convex shape of the vibrating membrane, various shapes and the sound pressure of a thin speaker using the same, and the frequency of abnormal noise generated by a sine wave sweep signal at 15 W input were investigated. The average sound pressure was calculated as an average value of 1 W / 1 m at 500 Hz, 600 Hz, 800 Hz, and 1 kHz. For the sweep test, Onsoku speaker test transmitter OG-423 was used. For the thin speaker, 10 units each having the same size as in Example 1 were produced.

The results of Examples 1 to 4 and Reference Examples 1 to 3 are summarized in Table 1 below.

  As a result of Table 1 above, no protrusion 1 is a comparative example of the conventional product, and the sound pressure 73 is the lowest among the experimental results. The rectangle of No. 2 is deep-drawn when the diaphragm is thermoformed, causing tearing or disconnection of the diaphragm and causing a problem in mass productivity. Furthermore, since the tip of the convex portion was wide, a collision with the magnet occurred, and noise was generated in half of the units. The trapezoid No. 3 had a sound pressure 6 dB higher than that of the conventional product, and there was no problem in the generation of abnormal noise or mass productivity. The inverted trapezoid of No. 4 could not be thermoformed by a male / female mold because the tip of the convex portion was widened. Since the triangle of 5 has a small number of voice coil turns that can be arranged at the tip of the convex portion having a high horizontal magnetic flux density, the sound pressure is 3 dB lower than that of the trapezoid. Further, the tip of the convex portion has to be rounded because the vibrating membrane is easily damaged. The nearly semi-elliptical shape of No. 6 had a sound pressure 6 dB higher than that of the conventional product, and there was no problem in the generation of abnormal noise or mass productivity. If the height of the protrusion is secured, the lower half of 7 is excessively widened compared to the semi-elliptical shape, and the sound pressure is reduced by 1 dB compared to the semi-elliptical shape. did. When the distance between the magnets is increased more than necessary, the horizontal magnetic flux density decreases, and it has been found that the semicircle of 7 is clearly disadvantageous than the approximate semi-ellipse of 6. The shape of the inverse Gaussian curve of 8 is close to that of a semi-elliptical shape of 6, and the result is 6 dB higher than that of the conventional product, and there was no problem in the generation of abnormal noise or mass productivity. The difference between the inverse Gaussian curve shape of 8 and the substantially semi-elliptical shape of 6 was only that the setting of the clearance of the mold at the lower part of the convex portion was different.

  From the above results, it was found that the shape of the convex portion of the diaphragm is preferably a trapezoidal shape, a substantially semi-elliptical shape, and an inverted Gaussian curve shape. The shape of these embodiments of the present invention needs to be a shape in which the tip of the convex portion is narrower than the bottom, like the inverted bell shape.

(Example 5 )
7 mm wide x 7 mm long x 2.5 mm thick neodymium magnets are arranged in 3 rows x 5 rows (15 pieces) on a flat yoke made of soft iron (SPCC) with a thickness of 1 mm and vibrate at a position facing the magnet 2. A thin speaker was produced by disposing the membrane 4 (see FIG. 2 for a sectional view). The external size of the thin speaker was 50 mm × 90 mm × thickness 8 mm, the frame 1 and the yoke were integrally processed by soft iron press molding, and a φ4 mm sound emitting hole 3 was provided between the magnets on the yoke.

  The vibration film 4 uses a heat-resistant LCP film having a thickness of 25 μm (Kuraray, CT-X100) as a sheet base 12, and a surface of the surface is made of a silicone resin with a thickness of 50 μm (S-9019, manufactured by Toho Sangyo). The sheet was bonded, and an aluminum wire (manufactured by Tokyo Special Electric Wire Co., Ltd., 2UEALW) was used as a linear conductor on the surface of the pressure-sensitive adhesive sheet substrate 12 (see FIG. 9A).

  When wiring the linear conductor, a wiring device disclosed in Japanese Patent Application Laid-Open No. 2001-126942 was used. And by the said apparatus, the voice coil 5 which consists of a two-dimensional spiral coil pattern by wiring a linear conductor on the sheet | seat base material 12 was formed (refer Fig.9 (a)). The wire conductor used for the wiring was a wire rod having a circular cross-sectional shape of 0.21 mm in diameter, in which a core wire made of an aluminum wire having a conductor diameter of 0.19 mm was covered with a polyurethane resin insulator. As the vibration film substrate, a heat-resistant foam with an adhesive to which a silicon pressure-sensitive adhesive sheet was bonded was used as the vibration film substrate. As the heat-resistant foam, a PEN foam having an average cell diameter of 3 μm and foamed 4 times (Furukawa Electric, ultra-fine foam sheet) and having a thickness of 0.5 mm was used. The impedance of the unit was 4Ω.

Unit of Comparative Example 5-1 (cross section of the configuration same as FIG. 1) PEN film described in Example 1 only was handed to LCP films were assembled in the same way.
Preparation of the vibrating film of Example 5-1 is as follows. A linear conductor is laid out on an LCP film with a silicone adhesive, and the same PEN foam with a silicone adhesive is laminated so that the silicon adhesive surface is bonded together, and collectively in the configuration of FIG. 9 (c). Thermoformed. The molding conditions were 120 ° C. and 5 seconds, which are not less than the glass transition point temperature (Tg = 116 ° C.) and not more than the melting point (mp = 266 to 273 ° C.) of PEN which is a thermoplastic resin.
Sound pressure measurements are carried out under the conditions described in Example 1, the (flat shape according to the vibration film 3) of Example 5-1 (vibrating film Comparative Example 5-1 in FIG. 18 (b) Fig. 9 (D)) was compared. As a result, a flat sound pressure frequency characteristic is obtained over substantially the entire frequency band, the average sound pressure in Example 5 -1 was 6dB greater than that of Comparative Example 5-1.

Next, a 100 μF bipolar capacitor is connected in series to the thin speaker, and the input voltage of the JIS signal is increased every 6 hours to increase the input voltage until the thin speaker breaks. went. The bipolar capacitor is used because the diaphragm and the magnet are likely to collide with each other in the vicinity of fo (minimum resonance frequency) of about 200 Hz due to a large input, so that the low range of the input signal is cut. As a result, in Comparative Example 5 having the structure of FIG. 1 having the planar vibration film (the vibration film is FIG. 3), the bubbles of the PEN foam collapsed with an average of 45 W input, and the vibration film was destroyed. The maximum temperature of the voice coil at this time was 210 ° C. as a result of measurement with a speaker voice coil thermometer (ONSOKU) OMT-205. On the other hand, Example 5-1 of the structure of Figure 2 forming a coil in a non-planar near the convex portion of the vibrating membrane, bubbles PEN foam at the input of the average 53W collapses, the vibration film was destroyed. Maximum temperature at this time the voice coil was the same approximately 210 ° C. Comparative Example 5-1. Thus, the embodiment 5-1 having the projections on the vibrating membrane, the heat radiation efficiency is improved by increasing the surface area than the vibrating film plane, power handling rose.

Further, after forming a voice coil 5 by directly laying a linear conductor on an adhesive-attached PEN foam bonded with a silicon adhesive sheet, an LCP film (pressing film 13) is formed in a manner of overlapping the adhesive sheet surface. Lamination was performed as shown in FIG. Thereafter, to prepare a vibration film of Example 5-2 collectively molded in the configuration of FIG. 9 (c). The unit was assembled in the same manner as described above, and the sound pressure measurement and input resistance test described above were performed. As a result, Example 5-2 showed approximately the same sound pressure as in Example 5-1, the average sound pressure is increased 6dB as compared to Comparative Example 5-1. Furthermore, like the even input resistance Test Example 5-1, the bubble of the PEN foam at the input of the average 53W collapses, the vibration film was destroyed. Maximum temperature at this time the voice coil was the same approximately 210 ° C. Comparative Example 5-1. Thus, the embodiment 5-2 having the projections on the vibrating membrane, the heat radiation efficiency is improved by increasing the surface area than the vibrating film plane, power handling rose.

  As described above, the same results can be obtained for the diaphragm base material for laying the linear conductors for both films and foams of different resin materials such as PEN and LCP, and the degree of freedom in mass production is high. It could be confirmed. Furthermore, the molding conditions of the vibration film may be matched with the molding conditions of the foam having a large thickness and high rigidity.

In the case of a tweeter having a reproduction band of 5 kHz or more, the amplitude of the vibration film is reduced, and by forming a voice coil between films made of heat-resistant resin, it can be molded integrally with the edge. Needless to say, for a small thin speaker such as a tweeter or a mobile phone, the method of the present invention can reduce the number of parts, simplify the assembly process, and excel in mass productivity. Further, if necessary, by providing a convex portion on the vibrating membrane even in a place without a coil, the rigidity of the vibrating membrane can be improved, abnormal vibration can be suppressed, and a low distortion thin speaker can be configured.
As mentioned above, although the resin material and the adhesive which were limited were described in the Example, it cannot be overemphasized that this invention is not limited to these conditions.

It is sectional drawing which shows the basic structure of a thin speaker. It is sectional drawing of the thin speaker which concerns on this invention. It is sectional drawing of the thin speaker which concerns on the conventional model 1. FIG. It is sectional drawing of the thin speaker which concerns on the conventional model 2. FIG. It is sectional drawing of the thin speaker which concerns on the conventional model 3. FIG. (A) is a fragmentary sectional view of the thin speaker which concerns on this invention, (b) is a fragmentary sectional view of the thin speaker which has a protrusion component for the comparison with the thin speaker which concerns on this invention. It is a fragmentary sectional view of the thin speaker which concerns on this invention. It is sectional drawing of the thin speaker which concerns on this invention. It is process drawing (a-d) which forms the diaphragm of the thin speaker based on the Example of this invention. (A) It is a top view of the diaphragm with which the voice coil of the thin speaker which concerns on this invention was formed. (B) It is a top view of the diaphragm by which the voice coil of the thin speaker which concerns on this invention was solder-joined with the tinsel wire on the copper foil. (C) It is a top view of the diaphragm which has a shape where a part of voice coil of the thin speaker concerning a reference example meandered. It is sectional drawing which shows distribution of the magnetic flux of the thin speaker based on this invention. It is a cross-sectional photograph of a PEN foam. It is sectional drawing of the process of forming the diaphragm of a thin speaker based on the Example of this invention. It is sectional drawing of the process of forming the diaphragm of a thin speaker based on the Example of this invention. FIG. 4 is a detailed view (cross-sectional view) in which a portion where both ends of a voice coil wired to a diaphragm of a thin speaker according to an embodiment of the present invention are solder-bonded to the tinsel wire 17 is coated with a resin (cross section). (A) Top view when a voice coil and a tinsel wire are butted and soldered together (b) Cross section when a voice coil and a tinsel wire are butted and soldered together FIG. 4 is a detailed view (cross-sectional view) in which a portion where both ends of a voice coil wired to a diaphragm of a thin speaker according to an embodiment of the present invention are solder-bonded to the tinsel wire 17 is coated with a resin (cross section). (A) Top view when the voice coil and the tinsel wire are butted and soldered on the copper foil (b) Cross section when the voice coil and the tinsel wire are butted and soldered on the copper foil FIG. 4 is a detailed view (cross-sectional view) in which a portion where both ends of a voice coil wired to a diaphragm of a thin speaker according to an embodiment of the present invention are solder-bonded to the tinsel wire 17 is coated with a resin (cross section). (A) Cross-sectional view when the voice coil and tinsel wire are entangled and soldered together (b) Top view when the extra length of the voice coil is loop-formed on the diaphragm and bonded and fixed The sound pressure frequency characteristic of the thin speaker which concerns on this invention and a comparative example is shown. It is process drawing (ad) which forms the diaphragm of the thin speaker which concerns on a reference example . It is a perspective view of the thin speaker based on a prior art. It is a perspective view of the thin speaker based on a prior art. FIG. 14 is a cross-sectional view for illustrating the operating principle of the thin speaker shown in FIG. 13. It is sectional drawing which shows distribution of the magnetic flux of a thin speaker shown in FIG. It is sectional drawing of the plane drive type speaker based on another prior art. It is sectional drawing of the voice coil part of the plane drive type speaker based on another prior art. It is a perspective view of the voice coil part of the plane drive type speaker based on another prior art. It is sectional drawing about the diaphragm with which the voice coil was formed in order to show the principle of operation of the plane drive type speaker based on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Frame 2 Magnet 3 Sound emission hole 4 Vibration film 5 Voice coil 9 Edge 10 Protrusion part 11 Parts 12 Sheet base material 13 Pressing film 14 Mold 15 Sheet 16 Adhesive 17 Kinshi wire 18 Resin 19 Solder 20 Copper foil 21 Plate 22 Extra length (loop)
41 Ribs

Claims (17)

On a yoke having a flat portion, a plurality of magnets having the same size are arranged in a lattice shape with a predetermined distance therebetween so that the magnetic pole surfaces of adjacent magnets are opposite to each other. In a thin speaker composed of a vibration film based on a thermoplastic resin having a pressure sensitive adhesive or an adhesive having a spiral coil arranged at a position corresponding to each of the magnetic pole surfaces, the magnetic pole of the magnet in the vicinity of the convex portion is molded to the vibration film portion corresponding to the outer edge of the surface, the eddy-wound and laid in a coil-like three-dimensional shape of the non-planar linear conductor in advance insulating coating relative to the yoke Further, the vibrating membrane forms a convex portion of the vibrating membrane by thermoforming in a temperature range not lower than the glass point transition temperature of the thermoplastic resin and not higher than the melting point. Convex The three-dimensional shape of the spiral coil formed in a convex outer surface of the diaphragm together, the spiral coil formed an insulating coated linear conductor having the pressure-sensitive adhesive or an adhesive layer of the vibrating film A thin speaker characterized by being embedded in a resin layer and another resin layer . The three-dimensional shape of the spiral coil formed in the vicinity of the convex part of the diaphragm is formed by forming the convex part of the diaphragm, forming an edge made of the diaphragm base, or forming a rib that increases the rigidity of the diaphragm. The thin speaker according to claim 1, wherein the thin speaker is formed by the same thermoforming. 3. The thin speaker according to claim 1, wherein the convex portion of the vibration film is narrower and narrower at a tip portion of the convex portion than a bottom portion on the vibration film side. The vibrating membrane is made of a sheet-like base material having an adhesive layer on at least one surface, and a linear conductor that is pre-insulated is wired on the sheet-like base material on the adhesive layer surface side. thin speaker according to claims 1 to 3, characterized. The adhesive layer of the sheet-like base material is made of an acrylic resin or a silicon-based resin, and after laying a linear conductor that is pre-insulated on the sheet-like base material on the adhesive layer surface side, The thin speaker according to claim 4 , wherein the speaker is fixed to a convex portion of the vibration film with an epoxy resin. The vibration film is formed by forming a plurality of spiral coils by fixing a linear conductor, which is pre-insulated with a semi-cured thermosetting resin, at least on a convex portion of the vibration film in a coil shape. thin speaker according to claims 1-5, characterized in that. The thin speaker according to any one of claims 1 to 6 , wherein a base material of the vibration film is a resin foam. The thin speaker according to claim 7 , wherein an average cell diameter of the resin foam is 50 μm or less. The thin speaker according to claim 7 or 8 , wherein the resin foam is a resin foam sheet made of at least one kind of thermoplastic polyester resin. The linear conductor is an insulation-coated conductor having at least one insulating layer on a surface layer thereof, and has a cross-sectional shape of at least one of a circle, a square, a rectangle, and a flat plate. The thin speaker according to 1 to 9 . Thin speaker according to claims 1 to 10 in which the diameter of said linear conductor characterized in that it is a 0.02Mm～0.4Mm. Thin speaker according to claim 1 to 11, characterized in that said linear conductor is Litz wire. The conductor of the linear conductor includes at least one of copper, copper alloy, aluminum, aluminum alloy, copper clad aluminum, copper clad aluminum alloy, copper plated aluminum, and copper plated aluminum alloy. 12. The thin speaker according to 12 . The base material of the vibration film is a heat resistant film having an adhesive layer on a surface on which a linear conductor is wired, or a heat resistant resin foam having an adhesive layer. 13. The thin speaker according to 13 . Adhesive layer of the base material of the vibrating membrane, at least an acrylic resin, silicone resin, consists of one epoxy resin, to claim 14, characterized in that the wired directly insulation coated linear conductor The thin speaker described. The thin speaker according to any one of claims 1 to 15 , wherein a linear conductor and a terminal wired on the vibrating membrane are solder-bonded via a lead wire (kinshi wire, stranded wire, braided wire). The vibrating membrane laid by linear conductor and the lead wire (tinsel wires, twisted, braided wire) connecting solder, the solder connection portion of claim 1-16, characterized in that coated with a resin Thin speaker.

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