WO2008051009A1

WO2008051009A1 - Sound converter

Info

Publication number: WO2008051009A1
Application number: PCT/KR2007/005228
Authority: WO
Inventors: Seung-Kiu Jeong
Original assignee: Em-Tech. Co., Ltd.
Priority date: 2006-10-24
Filing date: 2007-10-23
Publication date: 2008-05-02

Abstract

The present invention discloses a sound converter which can easily achieve the automation by including a terminal with a top plate function. The sound converter includes a frame (30), a yoke (20) inserted and installed inside the frame (30) an inner ring magnet (22) with inner ring top plate mounted thereon and an outer ring magnet (23) maintaining a predetermined interval from the side face of the inner ring magnet being mounted at the upper portion of the yoke (20), a diaphragm (60) provided with a coil portion at least partially inserted between the inner ring magnet (22) and the outer ring magnet (23) and a terminal (40) positioned at the upper portion of the outer ring magnet (23), for providing a magnetic path and an electric path between a coil (50) and an external connection terminal.

Description

Description SOUND CONVERTER

Technical Field

[1] The present invention relates to a sound converter, and more particularly, to a sound converter which can easily achieve the automation by including a terminal with a top plate function. Background Art

[2] Generally, a speaker converts electrical energy into mechanical energy by a voice coil existing in an air gap according to Fleming's left hand rule stating that a force is exerted on a conductor through which a current flows when the conductor is placed in a magnetic field. That is, when a current signal including a variety of frequencies is applied to the voice coil, the voice coil generates mechanical energy according to a current intensity and a frequency level. Therefore, a diaphragm adhered to the voice coil is vibrated, to thereby generate a sound pressure of audible intensity.

[3] A magnetic circuit of the speaker is designed so that a magnetic flux can cross the voice coil existing in the air gap at a right angle, by using a magnet (permanent magnet) and a top plate (or an upper plate) in a yoke made of a ferrous metal. The voice coil is adhered to the diaphragm, for generating an exciting force in the up-down direction by an input signal. Accordingly, the diaphragm fixedly adhered to a frame is vibrated to generate a sound pressure. The diaphragm has various shapes of waves so as to obtain an excellent response characteristic and remove a buckling phenomenon in the up-down vibration. The shape of the diaphragm functions as a design variable greatly affecting a frequency characteristic.

[4] Fig. 1 is a cross-sectional view illustrating a conventional microspeaker, and Fig. 2 is a state view illustrating a diaphragm and lead wires of Fig. 1.

[5] Referring to Fig. 1, the microspeaker includes a frame 1, a yoke 2 inserted and mounted inside the frame 1, an inner ring magnet 3 and an outer ring magnet 4 for transferring a magnetic force to the yoke 2 or receiving the magnetic force from the yoke 2, an inner ring top plate 5 and an outer ring top plate 6 for receiving the magnetic force from the inner ring magnet 3 or the outer ring magnet 4, and transferring the magnetic force to a voice coil 7 at a right angle, the voice coil 7 partially inserted into an air gap between the inner ring magnet 3 and the inner ring top plate 5 and the outer ring magnet 4 and the outer ring top plate 6, a diaphragm 8 into which the voice coil 7 is adhered, for generating a vibration by the up-down movement of the voice coil 7, and a protector 10 having a sound emitting hole 11 and protecting the diaphragm 8. [6] As illustrated in Figs. 1 and 2, lead wires 12 (a lead-in wire 12a and a lead-out wire

12b) of the voice coil 7 are fixedly adhered to the bottom face of the diaphragm 8 by a wire bond, taken out through the side face of the frame 1 or a groove (not shown) formed at the frame 1, and soldered to a terminal 14 along the outer side face of the frame 1, respectively. The terminal 14 connects a pair of external connection terminals (not shown, for example, lead wires, springs, pad type terminals, etc.) to the lead-in wire 12a and the lead-out wire 12b.

[7] The bonding process of the lead wires 12 of the voice coil 7 and the diaphragm 8 is performed by a wire bonding process of fixedly bonding the lead wires 12 to the bottom face of the diaphragm 8 by the wire bond. Although the bonding process requires high precision, it is manually conducted. As a result, the process time and the cost increase. Moreover, a defect frequently occurs during the process. That is, this process is the weakest part of the manufacturing process of the microspeaker.

[8] As the lead wires 12 are fixed to the diaphragm 8 by the wire bond, when an electrical signal is converted into a sound signal by vibration, the mass and rigidity distributions of the diaphragm 8 are not uniform. Accordingly, a split vibration is generated to deteriorate a sound characteristic. Disclosure of Invention Technical Problem

[9] An object of the present invention is to provide a sound converter which can maximize a size of a magnet without adhering a lead wire to a diaphragm.

[10] Another object of the present invention is to provide a sound converter configured to easily achieve the manufacturing automation.

[11] Yet another object of the present invention is to provide a sound converter which includes a terminal for performing a magnetic connection function and an electric connection function at the same time, and which optimizes the mounting position of the terminal to maximize a size of a magnet. Technical Solution

[12] In order to achieve the above-described objects of the invention, there is provided a sound converter, including: a frame; a yoke inserted and installed inside the frame, an inner ring magnet with an inner ring top plate mounted thereon and an outer ring magnet maintaining a predetermined interval from the side face of the inner ring magnet being mounted at the upper portion of the yoke; a diaphragm provided with a coil portion at least partially inserted between the inner ring magnet and the outer ring magnet; and a terminal positioned at the upper portion of the outer ring magnet, for providing a magnetic path and an electric path between a coil and an external connection terminal. [13] Preferably, the terminal and the outer ring magnet are insulated from each other.

[14] Preferably, the terminal has ferromagnetism.

[15] Preferably, the terminal includes a bonding portion positioned on the outer ring magnet with a predetermined interval from the inner ring magnet, and a connection portion formed outside the bonding portion and connected to the coil and the external connection terminal. [16] Preferably, the connection portion includes a coil connection portion and an external connection terminal connection portion. [17] Preferably, the terminal includes first and second terminals mounted to have a gap portion through which a lead portion of the coil passes. [18] Preferably, the lead portions pass through the gap portion and connect to bonding points of the first and second terminals, respectively. [19] Preferably, the lead portions travel in a curve shape from lead points of the coil, and connect to the bonding points of the first and second terminals. [20] Preferably, the lead points are more adjacent to the diaphragm than the bonding points. [21] Preferably, each of the first and second terminals includes a first member positioned to correspond to the top face of the outer ring magnet, a second member formed outside the first member and contacted with the lead portion of the coil, and a third member formed outside the first member and contacted with the external connection te rminal. [22] Preferably, the second member is formed over a predetermined angle from the gap.

Advantageous Effects

[23] In accordance with the present invention, the size of the magnet can be maximized without adhering the lead wires to the diaphragm. [24] In accordance with the present invention, the sound converter is configured to easily achieve the manufacturing automation, to thereby improve production efficiency. [25] In accordance with the present invention, the sound converter includes the terminal for performing the magnetic connection function and the electric connection function at the same time, and optimizes the mounting position of the terminal to maximize the size of the magnet.

Brief Description of the Drawings

[26] The present invention will become better understood with reference to the accompanying drawings which are given only by way of illustration and thus are not limitative of the present invention, wherein:

[27] Fig. 1 is a cross-sectional view illustrating a conventional microspeaker;

[28] Fig. 2 is a state view illustrating a diaphragm and lead wires of Fig. 1; [29] Fig. 3 is an exploded perspective view illustrating a sound converter in accordance with the present invention;

[30] Fig. 4 is a rear perspective view illustrating a frame of Fig. 3;

[31] Figs. 5 and 6 are front and rear perspective views illustrating a terminal of Fig. 3;

[32] Figs. 7 and 8 are perspective views illustrating coupling of the frame and the terminal;

[33] Figs. 9 to 12 are perspective views illustrating coupling states of coils;

[34] Fig. 13 is a view illustrating a current path of the sound converter in accordance with the present invention; and

[35] Figs. 14 and 15 are comparative graphs showing the performance of the conventional microspeaker and the performance of the sound converter of the present invention. Best Mode for Carrying Out the Invention

[36] A sound converter in accordance with preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, it is recognized that the scope of the present invention should not be limited to these preferred embodiments and accompanying drawings but to the claims as hereinafter recited.

[37] Fig. 3 is an exploded perspective view illustrating a sound converter in accordance with the present invention, Fig. 4 is a rear perspective view illustrating a frame of Fig. 3, and Figs. 5 and 6 are front and rear perspective views illustrating a terminal of Fig. 3. The sound converter includes a microspeaker or a receiver. The microspeaker will be taken as an example.

[38] As illustrated in Fig. 3, the microspeaker includes a yoke assembly 20 configured to transfer a magnetic force through an air gap A, a frame 30, the yoke assembly 20 being inserted and mounted in the frame 30 from the bottom, a terminal 40, a diaphragm 60 and a protector 70 being sequentially mounted at the inner face of the frame 30, the terminal 40 inserted and mounted at the inner or outer space of the frame 30, for providing a magnetic connection and an electric connection, a coil portion 50 (or a voice coil) at least partially inserted into the air gap A, for performing an up-down movement, the diaphragm 60 coupled to the upper portion of the coil portion 50 and vibrated by the up-down movement of the coil portion 50, and the protector 70 for protecting the diaphragm 60 from the outside.

[39] In detail, the yoke assembly 20 is inserted and coupled into the side face 30c formed at the lower portion of the frame 30, and includes a yoke 21, an inner ring magnet 22 positioned at the center of the yoke 21, an outer ring magnet 23 mounted to be spaced apart from the inner ring magnet 22 by the air gap A, and an inner ring top plate 24 for transferring a magnetic force from the inner ring magnet 22 or the outer ring magnet 23 to the coil portion 50 at a right angle. Normally, the inner ring top plate 24 has a diameter equal to or slightly larger than the diameter of the inner ring magnet 22, and contains a ferromagnetic material (for example, a material with high magnetic permeability, such as cold rolling steel sheet and a silicon steel sheet).

[40] As shown in Figs. 3 and 4, the frame 30 includes a side face 30a for housing the diaphragm 60 and the protector 70, a support face 30b to which the peripheral portions of the diaphragm 60 and the protector 70 are adhered, a side face 30c formed at the lower portion of the frame 30 so that the yoke assembly 20 can be inserted and mounted thereon, a side face 30d corresponding to or contacting the side face of the terminal 40, a bottom face 30e with sound emitting holes 32 and 35 formed thereat, insertion grooves 33a and 33b, an insertion portion 34 with insertion grooves 34a and 34b formed thereat for the contact (or connection) between external connection terminals (for example, lead wires, not shown) and the terminal 40, a support portion 36 contacted or adhered to a part of the top face of the terminal 40, and a support portion 37 contacted or adhered to a part of the bottom face of the terminal 40.

[41] Here, the insertion grooves 33a and 33b are selectively provided, which will later be explained in detail with reference to Figs. 11 and 12.

[42] The sound emitting holes 32 and 35 are provided in a pair and placed symmetrically.

In addition, the support portion 36 includes a support groove 36a contacted or adhered to a part of the side face and the top face of the terminal 40. The support portions 36 and 37 are provided in a pair and placed symmetrically.

[43] The insertion portion 34 protrudes to the outside, and includes the insertion grooves

34a and 34b so that parts of the terminal 40, namely, external connection terminal connection portions 44a and 44b can be exposed to the outside and connected to the external connection terminals, respectively. In the insertion grooves 34a and 34b, the portions for exposing the external connection terminal connection portions 44a and 44b and the portions for inserting the external connection terminals are integrally or separately formed. After the external connection terminal connection portions 44a and 44b and the external connection terminals are connected, the insertion grooves 34a and 34b can be filled with an insulating material.

[44] As depicted in Figs. 3, 5 and 6, the terminal 40 includes first and second terminals

41a and 41b. Here, outer ring top plate portions 42a and 42b corresponding to at least a part of the top face of the outer ring magnet 23 to transfer the magnetic force, coil connection portions 43a and 43b connected to lead portions 51 and 52 of the coil portion 50, and the external connection terminal connection portions 44a and 44b connected to the external connection terminals are integrally formed. The size of the terminal 40 increases due to the integral configuration. However, as the terminal 40 is positioned at the upper portion of the outer ring magnet 23 to perform the outer ring top plate function, the space occupied by the terminal 40 is smaller than the space occupied by the general terminal and outer ring top plate. Even if the size of the outer ring magnet 23 is maximized, it can be handled by increasing only the sizes of the outer ring top plate portions 42a and 42b. Therefore, spatial efficiency can be improved.

[45] In addition, the first and second terminals 41a and 41b are spaced apart from each other by a predetermined gap B. The lead portions 51 and 52 can travel through the gap B. When the lead portions 51 and 52 are vibrated by the up-down movement of the coil portion 50 during the operation of the microspeaker, the gap B prevents the lead portions 51 and 52 from contacting the terminal 40 in positions other than connection points (not shown) of the coil connection portions 43 a and 43b. As the terminal 40 performs the magnetic connection and the electric connection at the same time, it must have ferromagnetism.

[46] The outer ring top plate portions 42a and 42b correspond to the inner ring top plate

24, receive the magnetic force between the inner ring magnet 22 and the outer ring magnet 23 with the inner ring top plate 24, and transfer the magnetic force to the coil portion 50 at a right angle. That is, the outer ring top plate portions 42a and 42b provide a magnetic path. In order to prevent external transfer of the magnetic force, the outer ring top plate portions 42a and 42b must have the same diameter (outer diameter or inner diameter) as the diameter (outer diameter or inner diameter) of the outer ring magnet 23 to correspond to the outer ring magnet 23. That is, the bottom faces of the outer ring top plate portions 42a and 42b must be identical in shape to parts of the top face of the outer ring magnet 23.

[47] The outer ring top plate portions 42a and 42b correspond to the upper portion of the outer ring magnet 23 to protect the outer ring magnet 23 from an electric flow between the coil connection portions 43 a and 43b and the external connection terminal connection portions 44a and 44b or to protect the outer ring magnet 23 from heat generated in the connection (for example, welding) of the lead portions 51 and 52 to the coil connection portions 43 a and 43b. The top face of the outer ring magnet 23 and the outer ring top plate portions 42a and 42b must be insulated from each other. To this end, the outer ring magnet 23 and the outer ring top plate portions 42a and 42b are spaced apart by a predetermined interval, or provided with an insulating coating, an insulating plating or an interlayer insulating paper therebetween.

[48] The coil connection portions 43a and 43b are formed outside the outer ring top plate portions 42a and 42b, and spaced apart at a predetermined angle 'a' from the center of the gap B. Such an angle 'a' is required because, when the lead portions 51 and 52 travel through the gap B by a predetermined length, the bonding (for example, soldering) of the lead portions 51 and 52 and the coil connection portions 43a and 43b in the connection points is not broken by the vibration caused by the up-down movement of the coil portion 50, namely, the short is prevented, and the lead portions 51 and 52 are prevented from contacting the terminal 40 in positions other than the connection points.

[49] As the coil connection portions 43a and 43b function for the electric connection to the lead portions 51 and 52, the coil connection portions 43a and 43b have a shorter arc than the outer ring top plate portions 42a and 42b. That is, the coil connection portions 43 a and 43b have a smaller area than the outer ring top plate portions 42a and 42b.

[50] The external connection terminal connection portions 44a and 44b are connected to the outer ring tip plate portion 42a or the coil connection portion 43b, and also connected to the external connection terminals at their bottom faces through the insertion grooves 34a and 34b of the frame 30. That is, the coil connection portions 43 a and 43b and the external connection terminal connection portions 44a and 44b provide the electric path.

[51] Referring to Figs. 5 and 6, a terminal bonding body 40a is configured as one terminal through the ends of the external connection terminal connection portions 44a and 44b of the first and second terminals 41a and 41b described above. That is, in the terminal bonding body 40a, the first and second terminals 41a and 41b are connected by a bonding portion 45. Cutting grooves 46a and 46b are formed between the bonding portion 45 and the external connection terminal connection portions 44a and 44b. When the bonding portion 45 is cut along the bonding grooves 46a and 46b, the terminal bonding body 40a is divided into the first and second terminals 41a and 41b, which will later be explained with reference to Figs. 7 and 8.

[52] The coil portion 50 includes a body 50 formed by winding a coil a few times, and the lead portions 51 and 52 branching from lead points 51a and 52a of the body 50, respectively. The lead portions 51 and 52 travel from the upper to lower portions of the body 50, pass through the gap B, extend in a curve shape, and connect to the coil connection portions 43a and 43b. As shown in Fig. 3, the lead points 51a and 52a are positioned symmetrically, and the lead portions 51 and 52 travel symmetrically.

[53] The diaphragm 60 and the protector 70 are similar to those of Fig. 1 except that the lead portions 51 and 52 are not adhered to the bottom face of the diaphragm 60.

[54] Figs. 7 and 8 are perspective views illustrating coupling of the frame and the terminal. The frame 30 of Fig. 3 is manufactured by an extrusion process. As shown in Fig. 7, in a state where the terminal bonding body 40a is inserted into the frame 30, the frame 30 is injection-molded. As shown in Figs. 7 and 8, the bonding portion 45 is positioned outside, the external connection terminal connection portions 44a and 44b are positioned to be exposed through the insertion grooves 34a and 34b, and the cutting grooves 46a and 46b are positioned at one side portions of the insertion grooves 34a and 34b. Still referring to Fig. 7, the coil connection portions 43a and 43b are exposed to the upper portion so that the lead portions 51 and 52 can be connected thereto.

[55] The sound emitting hole 32 of the frame 30 is formed at the outside lower portion of the outer ring top plate portions 42a and 42b corresponding to the predetermined angle 'a' from the center of the gap B of the terminal bonding body 40a.

[56] As shown in Fig. 8, connection portions 81a and 81b of lead wires 80a and 80b which are one example of the external connection terminals are connected to the external connection terminal connection portions 44a and 44b through the insertion grooves 34a and 34b, respectively.

[57] The bonding portion 45 of the terminal bonding body 40a can be cut before or after the connection of the lead wires 80a and 80b. As the bonding portion 45 is cut, the terminal 40 of Figs. 3, 11 and 12 is obtained.

[58] Figs. 9 to 12 are perspective views illustrating coupling states of coils.

[59] As illustrated in the drawings, the lead portions 51 and 52 of the coil portion 50 travel through the gap B from the lead points 51a and 52a. The lead portions 51 and 52 are bent at the upper portion of the sound emitting hole 32, traveled along the peripheries of the outer ring top plate portions 42a and 42b, and connected to the coil connection portions 43 a and 43b.

[60] The lead portions 51 and 52 are extended in a curve shape to maintain a predetermined angle 'b' between the lead points 51a and 52a and the connection points 53a and 53b with regard to the center of the coil portion 50 or the yoke assembly 20. As described above, the lead portions 51 and 52 are extended in a curve shape with a sufficient length to prevent the short thereof. Here, the angle 'b' is set within 100 to obtain the sufficient lengths of the lead portions 51 and 52, and to prevent unnecessary contacts between the lead portions 51 and 52 and the terminal 40 during the travel from the top to bottom.

[61] As shown in Fig. 10, the lead points 51a and 52a are formed at the upper portion of the coil portion 50 adjacent to the diaphragm 60, so that the lead portions 51 and 52 are extended from the top to bottom not to unnecessarily contact the terminal 40 and the diaphragm 60.

[62] Fig. 11 shows one example of connecting the lead portions 51 and 52 to the coil connection portions 43a and 43b. The lead portions 51 and 52 are passed through the gap B, extended to the outside of the outer ring top plate portions 42a and 42b, bent at the upper portion of the sound emitting hole 32, and inserted into the insertion grooves 33a and 33b, respectively.

[63] According to the bending process at the upper portion of the sound emitting hole 32, in a state where a rod (not shown) is inserted through the sound emitting hole 32, the lead portions 51 and 52 can surround the rod and extend toward the insertion grooves 33a and 33b. Here, in a state where the lead portions 51 and 52 are inserted into the insertion grooves 33a and 33b, the bending process can be automatically performed. As the lead portions 51 and 52 are extended over the sound emitting hole 32 and inserted into the insertion grooves 33a and 33b, the lead portions 51 and 52 can be easily bent in a curve shape. Particularly, the extension of the lead portions 51 and 52 over the sound emitting hole 32 is associated with the shapes of the lead portions 51 and 52 and the angle 'b'.

[64] After the curve-shaped configuration, the welding is performed on the connection points 53a and 53b corresponding to the angle 'b'.

[65] As depicted in Fig. 12, the lead portions 51 and 52 existing after the connection points 53a and 53b are removed by cutting. A protection bonding 54a and 54b is carried out on the lead portions 51 and 52 on the coil connection portions 43a and 43b, for supplementarily preventing the short from occurring at the lead points 51a and 52a by the vibration of the coil portion 50. Such a protection bonding 54a and 54b can be performed before the lead portions 51 and 52 are cut.

[66] Fig. 13 is a view illustrating a current path of the sound converter in accordance with the present invention.

[67] For example, as for the current path, a current is introduced to the external connection terminal connection portion 44b, applied from the connection point 53b to the coil portion 50 through the lead portion 52, introduced from the coil portion 50 to the connection point 53a of the coil connection portion 43a through the lead portion 51, and applied to the external connection terminal connection portion 44a through the outer ring top plate portion 42a.

[68] A counter electromotive force is proportional to a winding number. As the terminal

40 is composed of the first and second terminals 41a and 41b separating from each other, the winding number is less than one. Generally, the coil portion 50 generates a counter electromotive force corresponding to 40 times. Therefore, according to the present invention, the influence of the counter electromotive force generated by the current flowing through the terminal 40 is very slight.

[69] Moreover, an AC magnetic field generated by the current (the sound current, etc.) applied to the terminal 40 will be observed. As 8Ω coil of IW output is mostly used for the lead portions 51 and 52, a flowing current is very small, about 0.35A. A magnetic flux density by the current is only about 0.00035T. On the contrary, as a ferromagnetic material is used for the inner ring magnet 22 and the outer ring magnet 23, a magnetic flux density is about 0.5T, so that the influence of the magnetic field by the current flowing through the lead portions 51 and 52 can be ignored.

[70] That is, when the terminal 40 provides the magnetic path and the electric path at the same time, the influence of the electric path on the magnetic path or the influence of the counter electromotive force by the electric path is extremely slight, which does not affect the operation of the sound converter at all.

[71] Figs. 14 and 15 are comparative graphs showing the performance of the conventional microspeaker and the performance of the sound converter of the present invention. The conventional microspeaker is the one shown in Figs. 1 and 2. In this embodiment, the conventional microspeaker and the sound converter of the present invention have the same size and characteristic except the element corresponding to the terminal 40.

[72] Referring to Fig. 14, with respect to a sound pressure level (SPL), a conventional characteristic graph I and a characteristic graph II of the present invention are almost identical at a frequency below IkHz. After that, a sound pressure which is a feature of the characteristic graph II of the present invention increases.

[73] As shown in Fig. 15, with respect to a total harmonic distortion (THD), the conventional characteristic graph I and the characteristic graph II of the present invention are almost identical in sound distortion degree.

[74] As explained with reference to Figs. 14 and 15, although the terminal 40 provides the electric path and the magnetic path to make the productive improvement, it does not adversely affect the characteristics (SPL, THD, etc.) of the sound converter.

[75] Although the preferred embodiments of the present invention have been described, it is understood that the present invention should not be limited to these preferred embodiments but various changes and modifications can be made by one skilled in the art within the spirit and scope of the present invention as hereinafter claimed.

[76]

Claims

[1] A sound converter, comprising: a frame; a yoke inserted and installed inside the frame, an inner ring magnet with an inner ring top plate mounted thereon and an outer ring magnet maintaining a predetermined interval from the side face of the inner ring magnet being mounted at the upper portion of the yoke; a diaphragm provided with a coil portion at least partially inserted between the inner ring magnet and the outer ring magnet; and a terminal positioned at the upper portion of the outer ring magnet, for providing a magnetic path and an electric path between the coil and an external connection terminal.

[2] The sound converter of claim 1, wherein the terminal and the outer ring magnet are insulated from each other.

[3] The sound converter of claim 1, wherein the terminal has ferromagnetism.

[4] The sound converter of claim 1, wherein the terminal comprises a bonding portion positioned on the outer ring magnet with a predetermined interval from the inner ring magnet, and a connection portion formed outside the bonding portion and connected to the coil and the external connection terminal.

[5] The sound converter of claim 4, wherein the connection portion comprises a coil connection portion and an external connection terminal connection portion.

[6] The sound converter of claim 1, wherein the terminal comprises first and second terminals mounted to have a gap portion through which a lead portion of the coil passes.

[7] The sound converter of claim 6, wherein the lead portions pass through the gap portion and connect to bonding points of the first and second terminals, respectively.

[8] The sound converter of claim 7, wherein the lead portions travel in a curve shape from lead points of the coil, and connect to the bonding points of the first and second terminals.

[9] The sound converter of claim 8, wherein the lead points are more adjacent to the diaphragm than the bonding points.

[10] The sound converter of claim 6, wherein each of the first and second terminals comprises a first member positioned to correspond to the top face of the outer ring magnet, a second member formed outside the first member and contacted with the lead portion of the coil, and a third member formed outside the first member and contacted with the external connection terminal. [11] The sound converter of claim 10, wherein the second member is formed over a predetermined angle from the gap.