KR100937335B1 - Micro speaker and method for fabricating the same - Google Patents

Abstract

PURPOSE: A micro speaker and a method for fabricating the same are provided to reduce labor costs and improve durability by making vibration plate assembly fabricating process automatic. CONSTITUTION: In a micro speaker and a method for fabricating the same, a frame(1) has an inner space to enhance a magnetic flux concentration is enhanced. A magnet(4) is attached to the lower surface of the frame. A yoke(2) is attached to the lower part of the magnet and forms a magnetic circuit together with a magnet. A vibration plate for sound generation is at the outer end at an inner upper end. A voice coil is fixed at the lower part of the vibration plate and is wound cylindrically.

Description

High efficiency micro speaker using FPCB {micro speaker and method for fabricating the same}

The present invention relates to a microspeaker, and more particularly, to a highly efficient microspeaker using FPCB to meet the trend of structurally demanding an ultra-lightweight and ultra-slim structure, and the expansion of high power and low sound reproduction ability in sound quality. It is about.

In general, a speaker is a device that converts an electrical signal into a voice signal has been applied to a variety of sound equipment. In particular, a small speaker mounted in a PDA, a notebook computer, an IMT2000 communication terminal, a mobile phone, an MP3 player, a netbook, etc. is called a micro speaker.

The PDA, notebook computer, IMT2000 communication terminal, mobile phone, MP3 player, netbook, etc., the user hears the sound from a certain distance away from the device, these portable devices are getting smaller according to the trend of miniaturization of the overall size and weight The microspeakers employed therein also continue to require downsizing.

On the other hand, contrary to the ultra-lightweight and ultra-slim structure requirements for micro speakers applied to portable devices, various music files are easily downloaded according to the development of wireless Internet technology and the implementation of IMT2000, and the sound quality is as high as an orchestra speaker. There is a need for broadband playback.

1 is a cross-sectional view showing a conventional microspeaker structure, Figure 2 is a plan view of the main portion showing the "R" shaping state of the voice coil with the protective plate of Figure 1 removed, with reference to these drawings for the structure and problems of the existing microspeakers Explain.

First, the structure of the microspeaker according to the prior art will be briefly described with reference to FIG. 1, a frame 11 having a space on an inner surface thereof, a magnet 14 magnetized in an up and down direction embedded in the frame, and the magnet 14. ) Yoke 12 forming a magnetic circuit, an upper plate 15 attached to the magnet 14 to form a magnetic circuit, and a vibration generating vibration plate having an outer end fixed to an inner upper end of the frame 11. 16, the voice coil 17 is wound in a cylindrical shape on the lower end of the diaphragm 16, the protective plate 19 to cover the open end of the frame 11, bonded to one side of the outer surface of the frame 11 PCB 20 is composed of (Printed Circuit Board).

In addition, an air hole 18 is formed in the frame 11 at a predetermined position so that air flows smoothly when the diaphragm 16 vibrates.

In the conventional microspeaker configured as described above, the voice coil 17 existing in the gap between the yoke 12 and the upper plate 15 is joined to the diaphragm 16, so that a current is generated in the voice coil 17. When drawn in, the electromotive force is generated up and down by the flow direction of the magnetic flux flowing through the upper plate 15 and the yoke 12 which are respectively bonded to the magnets 14 and the yoke 12 and the current flow of the voice coil 17 to the frame 11. Sound pressure is generated by vibrating the diaphragm 16 which is adhesively restrained.

As shown in FIG. 1, magnets are provided on both the inside and the outside of the voice coil, so that the speaker of the structure is called an internal and external magnet (or composite) speaker.

The basic structure and principle of operation of the speaker described above are the same, but the microspeaker configured to vibrate the voice coil inside the magnet is called a magnetic speaker.

On the other hand, the frame assembly consisting of the frame 11, yoke 12, magnet 14, top plate 15, PCB 20 or pin terminal, diaphragm assembly composed of voice coil 17 and diaphragm 16, In the existing microspeaker composed of a shield plate 19 that serves as sound emission and diaphragm protection, the voice coil 17 is responsible for the part corresponding to the path of the electrical signal among the components for converting the electrical signal into a voice signal, The coil lead wires 17a and 17b taken out from the voice coil are fixed by bonding to the bottom of the diaphragm using an adhesive 21 and soldered to the PCB 20 or the pin terminal attached to the outside of the frame.

More specifically described with reference to Figure 2 showing the "R" shaping state of the voice coil, in order for the voice coil and the PCB 20 coupled to the bottom of the diaphragm 16 to be energized with each other, the voice coil 17 to the PCB ( The process of drawing out and fixing in the direction of 20) is required. For this purpose, the voice coil 17 is bonded to the lower part of the diaphragm 16 with an adhesive or the like, and the lead lines 17a and 17b of the voice coil are formed on the diaphragm. It adhere | attaches with the adhesive agent 21 apply | coated to the bottom face of an edge part.

However, such conventional microspeakers suffer from various problems as follows.

In the diaphragm assembly process that combines the diaphragm 16 and the voice coil 17, an "R" shaping bonding process is used to bond the coil lead lines 17a and 17b and the adhesive 21 to the bottom of the diaphragm. This bonding process is a process that requires high precision and is difficult to automate. Therefore, it is extremely difficult to produce a uniform quality product, and the lead time of the process is very high, resulting in high cost. Will be created.

This is because the conventional bonding process is made by hand method, the processing angle, shape and length for the "R" of the lead coil 17a (17b) of the voice coil is different depending on the operator Because there is no choice but to.

In addition, the coil lead wires 17a and 17b and the adhesive 21 for attaching them are fixed to the bottom of the diaphragm 16. In the conventional case, the center of gravity of the diaphragm 16 is fixed to one side of the diaphragm according to the "R" shape. Because of the bias, when the electrical signal is converted into an acoustic signal, the vibration of the diaphragm and the dispersion of the steel component can cause split vibration, resulting in poor acoustic characteristics or poor disconnection.

In other words, the conventional diaphragm assembly process is the most vulnerable process of the microspeaker manufacturing process, which is a manual process, the most frequently generated defects and poor division vibration due to disconnection.

As a result, the conventional micro-speaker has a problem that the braking performance of the vibration system is weakened as the input electric energy is increased, and the unidirectional vibration with abnormal sound is generated greatly over the entire portion of the diaphragm. In addition, since copper is supplied to the coil with two strands of the coil residual line, which is the main component of copper, a significant progressive damage occurs as the vibration of the vibration system is excessive. This means that as the input energy increases and the reproduction region is extended to the low range, the distortion of the reproduced sound increases and the progressive disconnection defect increases.

What's more, recent mobile phones use the 64 poly signal, which contains a musical element, as a ring tone. In addition, portable electronic devices that want broadband reproduction and high power through the expansion of the low range are increasing. Accordingly, there is a need for a microspeaker that is extremely small and has a high input energy.

However, for example, a microspeaker with a diameter of 20 mm or less and a height of 5 mm or less, for example, its allowable input is only about 0.5 to 0.6 watts, and most of it is 700 Hz or more at low frequency. .

The bass reproduction limit frequency of the microspeaker is 700Hz or higher, resulting in no effect such as bass and bass during the reproduction of sound, and only the sharp and loud sound without the softness or liveliness in the overall reproduction sound quality. It means to reproduce.

In this case, it is conceivable to extend the bass reproduction limit frequency of the microspeaker unit to the low range in order to extend the reproduction sound band to the low range. However, in this case, even if the same energy is supplied to the microspeaker, the vibration width in the extended bass resonance portion becomes larger than before the expansion. This increases the likelihood of substantial distortion or breakage.

In consideration of the aftertaste and the balance of the reproduction band, if you want a low frequency reproduction limit frequency of 400 Hz in the free sound field condition of the micro speaker, as described above, the conventional micro speaker has a problem that severe disconnection and abnormal sound phenomenon occur. Holding it.

For this reason, in the conventional microspeakers, the allowable input is greatly reduced to 0.2 to 0.3 watts, and thus the reproduced sound becomes a very small amount of noise. As a result, in order to realize high power, the reproduction bass limit frequency range has to be moved to the treble region where the vibration width is as small as possible, and the allowable input has to be lowered when the reproduction of the high sound quality is focused on the contrary relation between the reproduced sound quality and the allowable input. In the case of conventional microspeakers, the vulnerability and limitations are revealed.

Therefore, a high-reliability microspeaker capable of wideband reproduction through expansion to the low range while realizing high output of sound by an electrically high input is realized.

In order to achieve this, there is a need for the development of a novel microspeaker having an innovative braking system having a stable braking function and a vibration-compliant electric signal transmission structure that is not disconnected despite an increase in vibration.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a vibration module for a microspeaker, a microspeaker having the same, and a method of manufacturing the same, in which a high output is possible and the bass reproduction capability can be expanded. There is this.

That is, the present invention improves the structure of the diaphragm assembly used in the existing microspeakers, while providing a microspeaker and a method for manufacturing the same, which can realize a higher level of performance in terms of volume and sound quality while satisfying the requirements for ultra-lightweight and ultra-slim structures. Its purpose is to.

According to one embodiment of the present invention to achieve the above object, the frame is made of ferrous metal to have a space on the inner surface and serves to help magnetic flux concentration, and the magnet magnetized in the vertical direction attached to the lower surface of the frame; A yoke attached to the lower side of the magnet to form a magnetic circuit together with the magnet, an acoustic generating diaphragm having an outer end fixed to an inner upper end of the frame, and a voice coil wound and wound in a cylindrical shape below the diaphragm. Consists of including

The diaphragm is formed of a central dome unit made of FPCB material consisting of a central dome and a coil connection part extending from the central dome to face each other in an outward direction thereof, and a rubber material attached to an outer circumference of the upper surface of the central dome. There is provided a microspeaker, characterized in that it comprises a configured edge portion.

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The effects of the present invention are as follows.

First, according to the present invention, it is possible to satisfy the demand for ultra-lightweight and ultra-slim structure, while satisfying the broadband and high power reproduction capability currently demanded by portable electronic devices.

In other words, according to the present invention, by eliminating the "R" crystal shape, which was inevitable in the conventional diaphragm assembly process, the fundamental vibration of the split vibration failure and the elimination of the solder connection between the coil and the lead wire are effectively eliminated. On the other hand, despite the increase of vibration during sound reproduction by providing a separate damper capable of performing a stable braking function, it is possible to expand the high power and low sound reproduction capacity.

On the other hand, according to the present invention, by eliminating the "R" crystal shape, which was inevitable in the conventional diaphragm assembly process, the fundamental vibration elimination problem is eliminated, and the disconnection defect at this part is effectively eliminated by eliminating the solder connection between the coil and the lead wire. Therefore, the process innovation of the diaphragm assembly process, which is the weakest process of the microspeaker manufacturing process, can be achieved.

In other words, when the FPCB is formed in the shape of a diaphragm and used as a diaphragm substitute, the present invention not only can omit the bonding process but also reduce the number of parts and improve the workability through automation. Has a measurable effect.

In addition, the present invention by directly connecting the coil and the FPCB of the speaker using the 'FPCB' it is possible to secure the price competitiveness by reducing the number of parts (PCB, wire, etc.).

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 3 to 7.

Figure 3 is a cross-sectional view showing a microspeaker structure according to the present invention, Figure 4 is a plan view showing the diaphragm assembly of Figure 3, Figure 5 is a perspective view showing only the central dome unit of Figure 4 separately.

Referring to these drawings, the microspeaker of this embodiment has a space on the inner surface and serves to assist the magnetic flux concentration in the frame (1) made of ferrous metal, and in the vertical direction attached to the lower surface of the frame (1) Magnetized magnet (4), yoke (2) attached to the lower side of the magnet (4) to form a magnetic circuit together with the magnet (4), and the outer end is fixed to the inner upper end of the frame (1) The sound generating diaphragm 5 and the voice coil 7 is wound in a cylindrical shape on the lower portion of the diaphragm 5; is configured to include. Reference numeral 3 is an upper plate attached to the magnet 4 to form a magnetic circuit.

On the other hand, the diaphragm 5 of this embodiment is a flexible printed circuit composed of a circular central dome 5a-1 and a coil connection portion 5a-2 extending to face each other in the radial direction from the central dome. The board comprises a central dome unit 5a of a flexible circuit board material and an edge portion 5b of a rubber material attached to an outer circumference of an upper surface of the central dome 5a-1.

At this time, a circuit pattern 9, which is a metal wiring, is formed around the edge of the circular center dome 5a-1 and the coil connection part 5a-2, and the edge part 5b of the coil connection part 5a-2 is formed. The portion corresponding to the convex portion of) is provided with a damper (D) rounded in the direction opposite to the convex portion rounded above the edge.

The circuit pattern formed around the edge of the center dome 5a-1 and the circuit pattern formed on the coil connection 5a-2 are electrically connected to each other, and around the edge of the center dome 5a-1. The formed circular circuit pattern also serves to indicate the attachment position of the voice coil 7.

On the other hand, on the circuit pattern of the coil connection portion 5a-2, a solder land 10a exposed for electrical connection with the lead wire 7a of the voice coil 7 is provided. In other words, the portion of the circuit pattern 9 except the solder land is protected as an electrically insulated state by a cover lay.

Meanwhile, the coil connecting portion 5a-2 may serve as a lead wire connected to another set of portable electronic devices, and at the end of the coil connecting portion 5a-2, the coil connecting part 5a-2 may be connected to another set of the portable electronic devices. Solder land 10b for electrical connection is provided separately.

That is, the set refers to another part electrically connected for power supply in a portable terminal, etc., and the coil connection 5a-2 may be formed to have a sufficient length for connection with another set.

For reference, the solder lands 10a and 10b shown in FIGS. 4 and 5 are substantially exposed through the lower surface of the FPCB to be connected to the voice coil or another set, but are translucent in nature of the FPCB. It is then shown from above that it is shown in the drawings.

The manufacturing process of the microspeaker of the present invention configured as described above is as follows.

First, looking at the manufacturing process of the present invention microspeaker, once the frame (1) made of ferrous metal to have a space on the inner surface and also serves to assist the magnetic flux concentration.

Subsequently, a magnet 4 magnetized in an up and down direction is attached to a lower surface of the frame 1, and a yoke 2 is formed on the lower side of the magnet 4 to form a magnetic circuit together with the magnet. At this time, the yoke 2 is provided with an air hole 8 located in the inner region of the magnet 4 after attachment to control the flow of air.

On the other hand, apart from the attachment of the frame 1 and the yoke 2, the diaphragm assembly manufacturing process proceeds in the following order.

First, the FPCB, that is, the central dome unit 5a, which is manufactured to have a predetermined circuit pattern 9 and then molded into a shape having the center dome 5a-1 and the coil connection portion 5a-2 of the diaphragm 5, is formed. Prepare.

At this time, a circular circuit pattern is formed around the edge of the central dome 5a-1, and a circuit pattern along the longitudinal direction is formed in the coil connection part 5a-2, and the coil connection part 5a-2 is On the circuit pattern, a solder land 10a for electrical connection with the lead wire of the voice coil 7 is provided.

Further, at the end of the coil connection 5a-2, another solder land 10b is provided for electrical connection with another set of portable electronic devices.

On the other hand, when the central dome unit 5a made of FPCB having the center dome 5a-1 and the coil connection portion 5a-2 as described above is prepared, an edge is formed on the upper surface of the edge of the center dome 5a-1. Attach the part 5b.

The voice coil is attached to the lower surface of the edge of the central dome 5a-1. At this time, a circular circuit pattern is formed at the edge of the central dome 5a-1 so that the attachment position of the voice coil 7 can be easily confirmed. In addition, the circuit pattern of the edge of the center dome 5a-1 may function as a marker for guiding the attachment position of the coil when automating the attachment of the voice coil 7.

On the other hand, after the voice coil 7 is attached, the solder land provided on the circuit pattern of the coil connection part 5a-2 forming the central dome unit 5a of the coil lead wire 7a of the voice coil 7 is provided. It is soldered to (10a) and electrically connected.

At this time, in the present invention, the center of gravity is shifted toward one side of the diaphragm 5 as the plus (+) line and the minus (-) line of the coil lead lines 7a of the voice coil 7 are drawn symmetrically in opposite directions. It is distributed to the right and left to maintain a balanced structure, which contributes to suppressing the split vibration along with other configurations.

On the other hand, after the manufacture of the diaphragm assembly as described above is completed, the sound generating diaphragm 5 is fixed to the inner upper end of the frame 1, the voice coil 7 is fixed.

The action of the microspeaker of the present embodiment constructed and manufactured as described above is as follows.

The microspeaker according to the present embodiment basically adopts a structure in which the materials of the edge portion 5b and the center dome unit 5a are different to enlarge the bass region, increase the output power, and suppress division vibration. In addition, an FPCB having a predetermined circuit pattern 9 is molded into a shape having a central dome 5a-1 and a coil connecting portion 5a-2 of the diaphragm 5, and used as a substitute for the dome (ie, body) of the diaphragm. By adopting the structure, defects due to disconnection and split vibration are fundamentally achieved through direct contact type pre-processing that connects the voice coil to the solder land of the coil connection portion 5a-2 where the circuit pattern is formed without the "R" shape. It can be solved.

That is, the present embodiment adopts a method of directly soldering the positive (+) and negative (-) lines of the voice coil 7 to the solder land of the FPCB 10.

Accordingly, compared to the conventional method, the mechanical defects such as disconnection and shaping of the coil are compensated for, and the split vibration of the microspeaker is divided by distributing the part of the center of gravity to one side of the diaphragm according to the "R" shape. It has an inhibitory effect.

In addition, according to the present embodiment, since the grinding process is eliminated, it is possible to innovate the process through automation or burn down of the diaphragm assembly manufacturing and assembly process.

Further, according to the present embodiment, the material of the central dome unit 5a is made of FPCB, which is advantageous for lowering the lowest resonance frequency, and the bass dome type damper D formed in the coil connection part 5a-2 is expanded while the bass reproducing ability is expanded. As a result, the ability to suppress amplitude during sound reproduction can be improved, thereby satisfying the demand for an ultra-lightweight and ultra-slim structure, as well as enabling high output while expanding a low sound reproduction band.

In particular, the damper (D) formed in the coil connecting portion (5a-2) of the present embodiment has a rounded structure in the reverse dome shape and the circuit pattern (9) is formed therein, so that it is more flexible and flexible, and effectively suppresses the disconnection, The lowest resonant frequency can be lowered, and the damper (D) 's amplitude suppression effect enables high output while improving bass reproducibility.

Further, according to the present embodiment, the circular circuit pattern formed around the edge of the center dome unit 5a provides the position indication function of the voice coil 7 attachment.

In addition, the power input unit constituting the central dome unit 5a is designed to serve as an existing terminal provided to input an electrical signal to the voice coil 7, or to the voice coil 7. As it is designed to serve as a terminal for inputting a signal and a lead wire for connecting the terminal to another set of portable electronic devices, it is possible to reduce cost by reducing the number of parts. Be able to innovate.

That is, in the conventional microspeaker, a method of connecting a wire or an FPCB to the PCB soldering part through soldering in order to allow a set and a current to flow through, but in this embodiment, a voice coil using "FPCB" Since the lead wire 7a and the connection line on the set side of (7) are directly connected to the coil connection part 5a-2, the number of parts (eg, PCB, wire, etc.) can be reduced, thereby improving workability and cost reduction. Will be.

In addition, in the present invention, disconnection and shorting are caused by electrically connecting the lead wire 7a of the voice coil 7 of the microspeaker using "FPCB" in which the circuit pattern 9 is protected by a coverlay which is an insulating protective layer. Durability to the back is further improved.

Figure 6 is a perspective view showing a central dome unit of the diaphragm assembly according to another embodiment of the present invention, the central dome unit according to the present embodiment is basically the same as the configuration of the above-described embodiment, but the radius of the central dome (5a-1) There is a difference in that the coil connecting portions 5a-2 extending along the direction are formed extending in all directions, and the solder lands are provided in the respective coil connecting portions 5a-2.

Referring to FIG. 6, when the central dome unit of the present embodiment is applied, since the coil connection part is formed in all directions, there is an advantage of widening the selection of the direction in which the lead line of the voice coil 7 is drawn out. When the voice coil is connected to two solder lands, there is an advantage in that the connection with the set can be performed through one of the remaining two coil connections.

7 is a perspective view illustrating a central dome unit of a diaphragm assembly according to another embodiment of the present invention. In this embodiment, coil connecting portions 5a-2 extending from all directions from the central dome 5a-1 are connected to each other. It is characterized in that the supporter portion (5a-3) is provided, the supporter portion (5a-3) has a form forming a concentric circle with respect to the central dome (5a-1).

In this embodiment configured as described above, since the supporter portions 5a-3 are connected to each other to support the coil connecting portions 5a-2 extending in all directions, the supporter portions 5a-3 serve to suppress amplitude.

For reference, FIGS. 6 and 7 also show that solder lands 10a and 10b are substantially exposed through the lower surface of the FPCB to be connected to the voice coil or set, but are semitransparent due to the material properties of the FPCB. Since it is shown in the drawings, the solder land is substantially exposed to the bottom.

On the other hand, the present invention is not limited to the above embodiments, and various changes can be made and modified without departing from the scope of the technical spirit of the present invention. For example, the central dome 5a-1 may have an elliptical shape or a track shape as well as the circular shape shown in the above embodiment.

Accordingly, the rights of the present invention are not limited to the embodiments described above, but are defined by what is stated in the claims, and those skilled in the art can make various modifications and adaptations within the scope of the claims. It is self evident.

The microspeaker of the present invention meets the trend of demanding the expansion of high power and low sound reproduction ability in sound quality while demanding an ultra-lightweight and ultra-slim structure, and can improve the productivity of work by shaping the voice coil leader line fixing structure. In addition, through automation, the process that was most vulnerable in microspeaker manufacturing can be innovatively improved, enabling cost competitiveness by reducing costs.

Accordingly, the present invention has a high industrial applicability and utility in various fields such as cellular phones, PDAs, MP3s, notebooks, and the like, as well as in various fields requiring micro-speakers.

1 is a cross-sectional view showing a conventional microspeaker structure

FIG. 2 is a plan view of the main parts, with the protective plate of FIG. 1 removed, showing the "R" shaping state of the voice coil; FIG.

3 is a cross-sectional view showing a microspeaker structure according to the present invention

4 is a plan view of the diaphragm assembly of FIG.

Figure 5 is a perspective view showing only the central dome unit of the diaphragm assembly of Figure 4 separately

Figure 6 is a perspective view of the central dome unit of the diaphragm assembly according to another embodiment of the present invention

Figure 7 is a perspective view of the central dome unit of the diaphragm assembly according to another embodiment of the present invention

Explanation of symbols on the main parts of the drawings

1: frame 2: York

4: magnet 5: diaphragm

5a: center dome unit 5a-1: center dome

5a-2: coil connection part 5a-3: supporter part

5b: Edge portion 7: Voice coil

7a: leader line 8: air hole

9: circuit pattern

10a: Solder land for voice coil lead wire connection

10b: Solder land for connection to set

Claims (9)

Frame (1) made of ferrous metal, and the magnet (4) magnetized in the vertical direction attached to the lower surface of the frame (1) to have a space on the inner surface and serves to help the magnetic flux concentration, and the magnet (4) A yoke 2 attached to the lower side to form a magnetic circuit together with the magnet 4, a sound generating diaphragm 5 having an outer end fixed to an inner upper end of the frame 1, and the diaphragm 5 It is configured to include; voice coil (7) is fixed to the cylindrical winding on the lower part of The diaphragm 5 includes a central dome unit 5a made of FPCB material consisting of a central dome 5a-1 and a coil connection part 5a-2 extending from the central dome so as to face each other in an outward direction thereof. An edge portion 5b made of rubber material attached to the outer circumference of the upper surface of the central dome 5a-1, The circuit pattern 9, which is a metal wiring, is formed around the edge of the center dome 5a-1 and the coil connection part 5a-2. And a damper (D) rounded in a direction opposite to the convex portion rounded above the edge portion (5b) at a portion corresponding to the convex portion of the edge of the coil connection portion (5a-2). delete The method of claim 1, And a circuit pattern formed around the edge of the center dome (5a-1) and a circuit pattern formed at the coil connection portion (5a-2). The method of claim 1, And a solder land (10a) exposed on the circuit pattern of the coil connection (5a-2) for electrical connection with the lead wire (7a) of the voice coil (7). The method of claim 4, wherein The coil connection (5a-2) is a microspeaker, characterized in that a separate solder land (10b) for the electrical connection with another set of portable electronic devices employing a microspeaker. The method of claim 1, The center dome (5a-1) is a microspeaker, characterized in that formed to form any one of the shape of a circle, oval, track. The method of claim 6, The coil connecting portion (5a-2) is characterized in that extending in all directions. The method of claim 7, wherein And a supporter part (5a-3) for supporting the coil connection part (5a-2) by connecting to each other. delete

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