JPS59501289A - electromagnetic acoustic transducer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] gong I eclipse This invention relates to electromagnetic acoustic transducers such as loudspeakers and headphones.

Certain known electromagnetic acoustic transducers include a diaphragm with an audible It has a frequency current conductor that divides the diaphragm into a series of parallel bands spaced one interval apart. Parallel current paths are formed along the longitudinal sides of the strip. A series of permanent magnets vibrate spaced apart from the plate and arranged to create a magnetic field perpendicular to each current path. , whereby an audio frequency current flows through the conductor.

The interaction between the audio frequency current flowing through the current path and the magnetic field creates a driving force that moves the diaphragm. vibrate.

This type of transducer uses a diaphragm with a relatively small mass that provides good high-frequency response. have However, for this type of converter.

If the driving force that causes the diaphragm to vibrate is applied only to the longitudinal sides of the parallel bands of the diaphragm, There is a drawback. The length of the band does not match the driving force applied only to the long sides of the band. As a result, standing waves are generated on the diaphragm.

It is undesirable for standing waves to occur on the diaphragm, and to prevent this, the width of the band is narrow. It has already been proposed to arrange parallel current paths with narrower distances from each other so that There is. This is not completely acceptable as it increases the cost of the converter and Separate.

This is a problem for converters with relatively large diaphragms to obtain good low-temperature response. It becomes a problem.

The present invention provides an electromagnetic acoustic transducer that overcomes or at least alleviates the drawbacks mentioned above. The purpose is to provide.

"Acoustically rigid" as used in this document with respect to areas formed on a diaphragm The expression means that the region is in undivided motion (i.e., it creates a standing wave in the region of the diaphragm). can vibrate to generate sound waves up to a predetermined frequency. shall mean that The electroacoustic transducer in one form of this invention includes a It has a diaphragm with an audio frequency current conductor on at least one surface, and the conductor is arranged in a waveform pattern. divide the diaphragm into multiple acoustically rigid regions and A current path is formed along the edges of the area, and the magnetic field generated by the array of magnets is By arranging it so that it interacts with the current path along the side, the audio frequency current The interaction between an audio current flowing through a conductor and an individual magnetic field along the current path The action causes the diaphragm to vibrate.

The wavy pattern can be castellated or serrated.

The region is preferably rectangular.

In some configurations, the diaphragm is a flexible material and the area is compressed by the tension of the diaphragm. It can be made acoustically rigid. In another configuration, the diaphragm is a flexible material. , @ region can be made acoustically rigid using stiffening means. This rigidity The increasing means are, for example, in each region of the diaphragm. It is a complex formation like a compound curve. Ru. In yet another arrangement, the diaphragm is made of a substantially 41% material. I can do it.

Reference is made to the following description of some specific embodiments of the invention as illustrated in the accompanying drawings. It is believed that this will further deepen the understanding of the present invention.

FIG. 1 is a perspective view of the transducer of the first embodiment, with the transducer shown for easy understanding of details. It is partially cut out.

FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1, with one portion cut away.

FIG. 3 is a plan view showing an alternative structure of the diaphragm of the embodiment shown in FIGS. 1 and 2; .

FIG. 4 is a flat panel showing yet another alternative construction of the diaphragm of the embodiment of FIGS. 1 and 2; It is a front view.

FIG. 5 is a perspective view of an alternative embodiment of the transducer, with the transducer partially shown for clarity. This is a specific cut.

6 is a plan view of the diaphragm of the transducer of FIG. 5; FIG.

FIG. 7 is a cross-sectional view taken along line 7--7 of FIG.

FIG. 8 is a cross-sectional view taken along line 8--8 of FIG.

No. 9121 is a schematic cross-sectional view showing the configuration of a diaphragm and a magnet of a converter according to still another embodiment. It is.

FIG. 1O is a schematic cross-sectional view showing the structure of the diaphragm and magnet of a converter according to yet another embodiment. be.

FIG. 11 is a schematic cross-sectional view showing a support system for a diaphragm according to yet another embodiment.

In Figures 1 and 2 of the accompanying drawings, the electromagnetic transducer of the first embodiment has a relatively large mass. has a small flexible diaphragm 11, which diaphragm is made of polyester, by way of example only. A large number of thin films such as polycarbonate thin film, polycarbonate thin film or polypropylene thin film. Formed from one of paper materials or a thin film of non-magnetic metal such as aluminum. Ru.

The diaphragm 11 is stretched in the longitudinal and lateral directions, and its outer periphery is made of highly rigid material. It is fixed to the outer peripheral frame 13 by adhesive or other method. This frame is attached to each side of the diaphragm. A space is created in which the moving plate can be displaced during its vibration.

On one side of the diaphragm 11 are audio frequency current conductors arranged in a castellated pattern. There is an I5 that divides one diaphragm into a plurality of substantially rectangular @ areas 17, and on the sides of the @ area A current path 16 is formed along it.

When the conductor is configured in a castle shape, each area 17 (every second area on the outer periphery of the diaphragm ) has a current path 16 along each side.

The other surface of the diaphragm has a shape similar to that of the conductor 15 and a phase difference of 180 degrees from that of the conductor 15. of each peripheral area by providing another audio frequency conductor (not shown) A current path can be provided along the outermost edge. This is the part of the outer area. a pair of current paths along the other side of the area and along each side of the other area. effective. Although the cost increases5, this configuration allows the outside edges of the peripheral area to be separated. This is advantageous because it applies an increased driving force to each side of the area. outer area The outer side of is adjacent to the outer periphery of the diaphragm, and this outer periphery itself is fixed to the outer peripheral frame 13. Therefore, no increased driving force is required on the outer side of the outer circumferential region.

In one example, the audio conductor 15 is in the form of a thin metal film of aluminum or copper. Aluminum is preferable because it has higher conductivity per unit weight. Yes. The diaphragm is made of Enotink, a laminate of metal thin film and plastic thin film. Do you want to make one?

Alternatively, the metal conductor can be printed, silk screened, or welded onto the diaphragm. Can be applied using conventional techniques. In another configuration, the conductor is glued to the diaphragm. It can take the form of aluminum or copper wire. The diaphragm is a thin metal film or In the case of other conductive materials 7) N, the conductor is naturally insulated from the diaphragm.

Each 0111 of the outer frame 13 has a backing member made of a magnetic material such as steel that allows sound to pass through. There are 19. Each backing member may be molded integrally with the outer peripheral frame 13 or It may be molded separately from the peripheral frame and fixed to the peripheral frame.

An array of permanent magnets 21 is attached to the side of each backing member 19 adjacent to the diaphragm 11. It will be done. The magnets 21 are arranged in a series of rows and rows, with each magnet in the array being attached to a respective one of the diaphragms. It is arranged within the projection plane of the region 17.

The shape of the magnet is a prism, and the outer surface, that is, the pole face 23, is geometrically similar to the shape of the region 17. It has a similar shape, in this case a rectangle. The pole faces of adjacent magnets in each array are mutually of opposite polarity, thereby creating a magnetic field between adjacent magnets.

The pole face of the magnet is placed close to the diaphragm to the extent that it does not come into contact with the pole face when the diaphragm is displaced. placed away from

Each backing member 19 provides a low reluctance path for the magnetic field of the face of the magnet adjacent to it. This has the effect of concentrating the magnetic fields existing between the pole faces 23 of the magnets. child The effect of is to make the magnetic field perpendicular to the respective current path 16.

As mentioned earlier in this document, each backing member 19 allows sound to pass through, but only one In the embodiment shown, this includes holes 25 in the area between adjacent magnets of the backing member. This is achieved by forming.

The interaction between the audio frequency current flowing along the current path 16 and the respective magnetic field is , a substantially direct driving force is applied to each current path on the diaphragm, which causes the diaphragm to vibrate. Ru. Therefore, driving force is applied to each side of region l1i17 with the current path on the gold side. child This, combined with the acoustically rigid nature of the fI4 region, ensures that the area of the diaphragm is uniform. vibrate in undivided motion.

Figures 3 and 4 of the drawings show variations in the arrangement of audio frequency current conductors on the diaphragm; The reference numbers in these two figures are the same as those described with respect to the embodiment in figures 1 and 2. Show parts. In the structure shown in Figure 3, the conductors are arranged in a sawtooth pattern. , dividing the diaphragm 11 into a plurality of substantially rectangular regions 17 . Structure shown in Figure 4 , the conductors 15 are arranged in a sawtooth pattern to connect the diaphragm 11 to a plurality of substantially Divide into triangular regions. In this configuration, the polar face of the magnet 21 (indicated by a dotted line) ) is geometrically similar to the shape of the triangular region.

Next, Figures 5.6.7 and 8 of the accompanying drawings show an audio frequency conductor 115 (separated) on each side. For ease of illustration, the conductor on the bottom of the diaphragm is omitted in Figure 5). An electroacoustic transducer with a moving plate 111 is shown. Audio frequency conductors 115a and 11 5b are arranged in a castellated pattern on the diaphragm, and the diaphragm is arranged in a plurality of substantially rectangular shapes. The current path 116 is divided into regions 117 and current paths 116 are formed along the sides of the regions. Conductor 1 15a23 and 115b have similar shapes to each other, but their phases differ by 180 degrees l9( 6 of the drawings), whereby at least one conductor path 116 along each side of each region. actual.

A pair of current paths runs along each side of all areas, apart from the outer peripheral area of the diaphragm. brought about. The conductors 115a and 115b are arranged on the diaphragm in a different pattern, For example, it should be understood that the scales are arranged in a serrated pattern. However, territory Preferably, area 117 is substantially curved in shape. Furthermore, if necessary If (as in the embodiments of Figures 1 and 2) there is only one conductor on the diaphragm. should also be understood.

The diaphragm 111 is formed from a flexible thin plate material, and means 1 for imparting rigidity to the region 117 18 to make the CH region acoustically rigid.

In the configuration shown, the stiffening means 118 each have vibrations in the 0) region. Consists of a composite formation formed into a plate. In particular, in the configuration shown in Figure 1, the composite formation Each object has the shape of a hemispherical dome, and each dome is the outer circumference or is integrated with the rectangular substrate in the vicinity. In another construction, the composite formation is A hollow cone integrated with a rectangular substrate or a hollow square with a rectangular base. It may also be a pyramid.

(The dragon plate 111 is made of excessive plastic such as polyester or polycarbonate. It can be manufactured from metals such as copper alloys, or composite materials. diaphragm The lit can be manufactured using suitable techniques such as vacuum forming, injection molding, or compression molding. A composite object 118 can be formed.

The diaphragm 111 is supported on its outer periphery by a suspension system 120, and this suspension string is connected to the S@plate. does not prevent the diaphragm from vibrating in a direction substantially perpendicular to the plane of the diaphragm. Illustrated embodiment In this case, the suspension system is formed integrally with the diaphragm and fixed to the outer peripheral frame 113. another In the configuration, the suspension strings are formed separately from the diaphragm, and the diaphragm has the suspension strings formed on its outer periphery. It can also be fixed by bonding or other methods.

On the opposite side of the diaphragm 111 from the protruding side of the composite formation 118, a spacer is provided on the diaphragm 111 to maintain a gap. Therefore, a backing member 119 made of a magnetic material such as steel that allows sound to pass through is placed. . The backing member 119 can be formed integrally with the outer frame 113 or separately. Ru.

An array of permanent magnets 121 is attached to the side of the backing member 119 facing the diaphragm 111. It will be done. As in the previous examples, the magnets 121 are arranged in a series of rows and rows. arranged, each magnet is placed within the projection plane of each square h3i 117, and the adjacent The polar faces of the magnets have very different polarities. The shape of the magnet 121 is a prism, and the pole face 123 The shape of is geometrically similar to the shape of @ area 117.

The backing member provides a path of low reluctance to the magnetic field on the surface of the magnet adjacent to the backing member. This has the effect of concentrating the magnetic field that exists between the pole faces. This effect is vi, field is perpendicular to each current path.

The transducer of this embodiment functions in a somewhat similar manner to the previously described embodiments. In other words, the acoustic rigidity of @ region 117 is independent of the tension of the diaphragm, and is independent of the composite structure 11. 8.

The transducers of the embodiments shown in Figures 9, 10 and 11 are illustrated in Figures 5 through 8. The reference numbers used in Figures 9, 10 and 11 are The same parts as described with respect to the embodiments of FIGS. 5 to 8 are shown.

The transducer shown in one diagram in Figure 9 is the one shown in Figures 5 to 8, and one side of the diaphragm. that there is an audio frequency conductor 115 only at the edge and that the conductor contacts the diaphragm 111 at the edge The difference lies in the shape of the ribbon worn. Each formed by this ribbon The current path 116 is connected to the adjacent pole piece 12 attached to the pole face A of the permanent magnet 121. It is located within the area 122 between 4 and 4. In this configuration, the diaphragm 111 is.

It is possible for a conductor to undergo a relatively large displacement without escaping the influence of the magnetic field. Ru. The ribbon can be bent along its length to increase lateral stiffness.

In an alternative configuration, the ribbon 115 is a mount that projects outwardly from the plane of the diaphragm. It can also be glued or otherwise fixed to the stand.

In the configuration shown in FIG. The backing member 119 is provided in the projection plane of the other region 117b; There is a pole piece 126 integral with or in contact with. The permanent magnet 121 The pole faces are arranged to have a 1.1lffi property, and each pole piece 124 is provided. It's a fixture. A magnetic field exists between adjacent pole pieces 124 and 126; The configuration eliminates the need for permanent magnets corresponding to each region 117.

An alternative arrangement for supporting diaphragm 111 is shown in FIG.

The diaphragm is not supported by its outer circumference, but by a plurality of elastic support members 1 inside it. Supported by 29. The elastic support member 129 is a composite material that increases the rigidity in the diaphragm. Each vertex 131 of the number forming part 118 and the 4 It is attached between the member 133 and the highly resilient member 133. With this form of support system, Using a diaphragm that allows adjacent @ regions 117 to make limited angular movements with respect to each other becomes possible.

In yet another embodiment (not shown), the diaphragm is formed of a rigid material. You can. In this configuration.

The diaphragm has an outer IfI section similar to that used in the embodiments of Figures 5 to 8. or by a suspension string similar to that used in the embodiment of FIG. It can be supported by

that the scope of this invention is not limited to the scope of the embodiments described herein; Moreover, various changes or modifications can be made without departing from the spirit of this invention. should be understood.

IG I IG 2 Japan G3 IG 5 FIG 6 FIG 9 lG10 international search report InIIIfIIa+101+1^””II””0PCT/AIJ! +3/'0 0084 Continuation of page 1 Priority claim @ September 13, 1982 ■ Australia (AU) ■ PF5845 ■November 19, 1982 ■Australia (AU) ■PF6877

Claims (1)

[Claims] I. The diaphragm has an audio frequency current conductor on at least one side. By arranging the conductors in a wave-shaped pattern, the diaphragm is divided into multiple acoustically rigid regions. area and form a current path along the sides of the area, thereby generating an array of magnets. Arrange the area so that the generated magnetic field interacts with the current path that aligns with one edge of the area. While an audio current flows through a conductor, the audio current flowing along the current path and An electromagnetic acoustic transducer in which the interaction between individual magnetic fields causes a diaphragm to vibrate. 2. The converter according to claim 1, in which the waveform has a castle shape. 6. Claim 1. A term converter with a sawtooth waveform. 4. A transducer according to any one of the above claims, wherein the area is rectangular. 5. In the transducer according to any one of the above claims, one audible If on each side of the diaphragm. f-wave current conductors, each rust area having at least one current path along each side of it. Conductors arranged in a straight pattern. 6. The YA device according to any one of the above claims, wherein the magnet is a permanent magnet and is magnetic. It is attached to a backing member of body material, and the backing member allows sound to pass through. 7. The transducer according to any one of the above claims, in which the diaphragm is made of a flexible material. A region made acoustically rigid by the tension applied to the diaphragm. 8. In the converter according to claim 7, the diaphragm is fixed to the outer frame at its outer periphery, and the outer periphery is fixed to the outer frame. The frame is formed integrally with the backing member or is fixed to the backing member. 9. The transformer according to any one of claims 1 to 6, in which the diaphragm is made of a flexible material. The area is formed on the diaphragm to increase the acoustic made rigid. lO8 Claim 9 In the transducer of Ql, the means for increasing the stiffness suppresses vibration in each region. consisting of a composite formation of plates. 11. The converter according to claim 1O, in which the composite formation has a side of each area and a side of the next area. The first consists of an integral hemispherical dome. 12. Claim 1 A transducer of Oqi, wherein the composite formation has sides of each region and Consisting of hollow cones that gradually come together. 13. Variation of Claim 1O (1! In the device, the composite formation has a side of each region It consists of a hollow square pyramid that gradually becomes one. 14. The transducer according to any one of claims 1 to 6, in which the diaphragm substantially Something made of rigid material. 15. In the transformer according to any one of claims 1 to 7, the shape of the pole face of the magnet is the shape of the region. 616, which is geometrically similar to 616, is a converter in any one of the ranges listed below, There is one aforementioned permanent magnet corresponding to each region of the diaphragm, with the pole faces of adjacent magnets Those that are of different polarity. 17. Which of claims 1 to 15 is the converter of item 1, and the diaphragm is purchased separately. There is one aforementioned permanent magnet corresponding to each region of the There is a piece, and the pole faces of the magnet have the same polarity. 18. The transducer according to any one of claims 9 to 15, in which the diaphragm is Supported within the sides by a plurality of elastic support members. Support paulownia or something that does not interfere with the aforementioned vibration of the diaphragm. 19. The transducer according to claim 18, in which each elastic support member is connected to each of the plurality of diaphragms. Something that is attached to the diaphragm at the top of the composite material. 20. Electromagnetic sound W transducer substantially as described herein with reference to the accompanying drawings.