KR20150047748A

KR20150047748A - Speaker Having Flat-Type Voice Coil

Info

Publication number: KR20150047748A
Application number: KR1020130127595A
Authority: KR
Inventors: 유승열
Original assignee: 주식회사 드림소닉
Priority date: 2013-10-25
Filing date: 2013-10-25
Publication date: 2015-05-06

Abstract

A flat speaker capable of preventing performance deterioration due to heat is disclosed. According to an aspect of the present invention, there is provided a planar speaker comprising: a voice coil plate disposed in a magnetic space between a pair of magnetic bodies disposed at a predetermined interval from each other, the voice coil being formed on a planar base substrate surface side; A diaphragm coupled to an upper end of the voice coil plate exposed to the outside of the magnetic space and vibrated by an electromagnetic force generated in the voice coil plate; And a heat radiation film made of a thermally conductive material and having a first region attached to the surface of the voice coil plate and a second region thermally connected to the first region and exposed to the outside of the vibration plate.

Description

[0001] Speaker Having Flat-Type Voice Coil [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker, and more particularly, to a flat speaker having a flat voice coil plate.

The speaker has a voice coil and a diaphragm disposed in a magnetic field, and generates a sound wave of a small-sized wave form in the air by vibrating the diaphragm using a Lorentz force generated in the voice coil by an electric signal. Conventionally, a circular speaker that vibrates a cone-shaped diaphragm by using a voice coil coiled in a cylindrical shape has been widely used. However, recently, due to the trend of downsizing and thinning of a display device or a mobile terminal equipped with an audio system, The use of flat-panel loudspeakers to reduce installation space is increasing.

The flat plate type speaker generally includes a pair of magnetic bodies arranged at predetermined intervals from each other to form a magnetic space in which a magnetic field is formed therebetween, a planar voice coil plate disposed in the magnetic space, And a diaphragm that is vertically coupled to the upper end of the voice coil plate and vibrates by the motion of the voice coil plate. The voice coil plate includes a base plate in the form of a plate or a film, and a voice coil printed on the surface of the base plate in a track form or in a similar form.

Joule heat due to the electric signal is generated in the voice coil during operation of the speaker. As the thickness of the voice coil is thin and the degree of winding integration is high, the resistance value increases and more heat is generated. However, in the case of the flat plate type speaker, since the voice coil plate is disposed in a narrow space between the pair of magnetic bodies, it is not easy to emit such string heat. Unreleased heat may accumulate on the voice coil plate and cause thermal deformation of the base substrate. Also, the accumulated heat is transmitted to the adjacent magnetic body to weaken the strength of the magnetic field. This is because magnetization disappears when the ferromagnetic material is heated to a Curie temperature. As described above, there is a problem that the performance of the speaker is liable to be deteriorated by the heat generated in the voice coil plate in the flat plate type speaker.

Korean Patent Registration Nos. 10-0576266, 10-0576267, 10-0533715

Disclosure of Invention Technical Problem [8] The present invention has been proposed in order to solve the above problems, and it is an object of the present invention to dissipate heat generated from a planar voice coil plate to the outside of a speaker to prevent deformation of internal structures and deterioration of speaker performance The present invention has been made in view of the above problems. Another object of the present invention is to provide a flat-type speaker capable of preventing thermal deformation by improving the structure of an inner structure of a speaker, in particular, a voice coil plate.

According to one aspect of the present invention, there is provided a flat speaker, which is disposed in a magnetic space between a pair of magnetic bodies disposed at a predetermined interval from each other, A voice coil plate formed on the base plate; A diaphragm coupled to an upper end of the voice coil plate exposed to the outside of the magnetic space and vibrated by an electromagnetic force generated in the voice coil plate; And a heat radiation film made of a thermally conductive material and having a first region attached to the surface of the voice coil plate and a second region thermally connected to the first region and exposed to the outside of the vibration plate.

The diaphragm has a through hole penetrating the inside toward the magnetic space and the opposite outside and the first area and the second area of the heat radiating film are thermally connected to each other through the through hole.

The heat radiating film may be formed of one thermally conductive film in which the first region and the second region are continuous through the through holes. The upper surface of the first region is exposed to the outside of the diaphragm through the through hole, and the upper surface of the first region is exposed to the outside of the diaphragm, May be attached to the outer surface of the diaphragm in contact with the exposed upper end.

The heat radiating film may be a flat thermally conductive film whose thermal conductivity in the planar direction is higher than thermal conductivity in the thickness direction.

The base substrate may have a shape in which a corner portion farther from the diaphragm is chamfered. Further, the base substrate may be chamfered so that the corner portion is rounded with a predetermined radius of curvature.

According to an aspect of the present invention, there is provided a planar speaker comprising: a voice coil plate disposed in a magnetic space between a pair of magnetic bodies disposed at a predetermined interval from each other, the voice coil being formed on a planar base substrate surface side; And a vibration plate coupled to an upper end of the voice coil plate exposed to the outside of the magnetic space and vibrated by an electromagnetic force generated in the voice coil plate, wherein the base plate has a shape in which a corner portion farther from the vibration plate is chamfered Lt; / RTI >

According to the present invention, since the heat generated in the planar voice coil plate is discharged to the outside of the diaphragm of the loudspeaker through the heat radiation film, it is possible to prevent the deformation of the internal structure or the deterioration of the speaker performance, Is provided. According to the present invention, there is also provided a planar speaker capable of preventing thermal deformation by improving the internal structure of the speaker, in particular, the base substrate structure of the voice coil plate.

1 is a perspective view showing a voice coil plate and a diaphragm in a flat type speaker according to an embodiment of the present invention.
2 is a cross-sectional view of a planar speaker according to the embodiment of FIG. 1, taken along line AA '.
3 is a front view showing a voice coil plate and a diaphragm in the flat speaker according to the embodiment of FIG.
4 is an enlarged view of a corner portion of a voice coil plate in a flat type speaker according to an embodiment of the present invention.
5 is an enlarged view showing a corner portion of the voice coil plate in the flat type speaker according to the embodiment of the present invention.
FIG. 6 is a cross-sectional view illustrating a cross-sectional voice coil plate and a diaphragm in a flat speaker according to an embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a double-sided flat type voice coil plate and a diaphragm in a flat type speaker according to an embodiment of the present invention.
8 shows simulation results of thermal stress and thermal deformation according to the chamfering of the corner portion of the voice coil plate in the flat type speaker according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below can be modified in various ways, and the scope of the present invention is not limited to the following embodiments. The embodiments of the present invention are provided to clearly convey the technical idea of the present invention to those skilled in the art.

1 is a perspective view showing a voice coil plate and a diaphragm in a flat type speaker according to an embodiment of the present invention. According to this embodiment, the upper end of the planar voice coil plate 100 having the voice coil 11 on the surface side of the base substrate 10 is vertically coupled to the diaphragm 20 that vibrates the air. A heat radiation film (30) is attached to the surface of the voice coil plate (100) and the outer surface of the vibration plate (20).

The first region 31 of the heat radiating film 30 is attached to the surface of the voice coil plate 100 and the second region 32 of the heat radiating film 30 is attached to the vibration plate 30. [ Is attached to the outer surface of the second region (20), and the first region (31) and the second region (32) are thermally connected to each other. In the present embodiment, the heat conduction through the slit-shaped through-hole 21 provided at the center of the diaphragm 20 is one thermally conductive But they are not limited thereto. For example, the first region attached to the voice coil plate 100 and the second region attached to the surface of the diaphragm 20 are separated from each other. Any one of them may penetrate the diaphragm 20 directly Or may be indirectly connected using a thermally conductive structure such as a third thermally conductive film.

The heat radiating film 30 may be attached to one or more of the heat radiating films 30 with different areas depending on factors such as the amount of heat generated by the voice coil plate 100. It is preferable that the mounting position of the heat radiating film 30 is symmetrically arranged with respect to the central axis of vibration of the diaphragm 20 and the voice coil plate 100 for balanced vibration of the diaphragm 20 . In addition, the heat radiating film 30 may be attached to both sides of the voice coil plate 100 as in the present embodiment, or may be attached to only one side of the voice coil plate 100.

The heat radiating film 30 is advantageous in diffusing heat generated in the first region 31 into the second region 32 and emitting it mainly because the thermal conductivity in the plane direction is relatively higher than the thermal conductivity in the thickness direction. A carbon-based heat dissipation sheet such as a Graphene sheet, a graphite sheet or a carbon nanotube sheet (CNT sheet) can be employed. The heat dissipation film 30 can be attached to other structures using a pressure sensitive adhesive or an adhesive. A thermally conductive pressure sensitive adhesive or an adhesive layer is formed on one side of the heat dissipation film 30 to easily adhere thereto. The graphene sheet is formed by flattening graphene pieces chemically or physically peeled off from graphite in a film-like base material, and the graphite sheet is obtained by processing artificial graphite or natural graphite into a thin film form, and the carbon nanotube sheet is made of carbon And a high thermal conductive resin layer in which nanotube pieces are uniformly dispersed in a plane.

Meanwhile, the periphery of the diaphragm 20 may be connected to a fixing structure such as a housing of a speaker through a damper structure, but is not shown here for the sake of convenience of explanation.

2 is a cross-sectional view of the planar speaker according to the embodiment of FIG. 1, taken along the line A-A '. As described above, the voice coil plate 100 is installed in the magnetic space between the pair of magnetic bodies 40, and the upper end thereof is engaged with the diaphragm 20. The pair of magnetic bodies 40 form a magnetic field in a direction passing through the voice coil plate 100 and may include a permanent magnet 41 and a yoke plate 42 disposed above and below the permanent magnet 41. However, the present invention is not limited by the form of the magnetic body.

2 shows an example in which the voice coil plate 100 and the diaphragm 20 are coupled together with the heat radiation film 30. As shown in the figure, a voice coil plate 100 having the heat radiating film 30 attached thereto is inserted into a slit-shaped through hole 21 at the center of the diaphragm 20, A second region (32) of the film (30) is attached to the outer surface of the diaphragm (20). The attachment may be performed using a pressure sensitive adhesive or an adhesive, or may be performed using a separate tape.

The size and shape of the through-hole 21 can be variously modified. For example, when the voice coil plate 100 is attached to the inner surface of the diaphragm 20 without being inserted into the diaphragm 20, the through hole may be formed to be small enough to pass through only the heat radiation film 30.

3 is a front view showing a voice coil plate and a diaphragm in the flat speaker according to the embodiment of FIG. In the present embodiment, the voice coil 11 may be wound on one side or both sides of the base substrate 10 in the form of a track, for example. As another example, the voice coil 11 may be a conductive pattern printed on one side or both sides of the base substrate 10 in a track shape. The voice coil 11 includes a section extending parallel to the diaphragm 20 so as to vibrate the diaphragm 20 in a direction perpendicular to the plane in a space in which a magnetic field is formed. Both ends of the voice coil 11 are connected to the terminals of the speaker via the lead wirings, so that a current accompanied by the electric signal flows to the voice coil 11.

As a material of the base substrate 10, a high heat resistant polymer film such as a polyimide film may be employed. Since the voice coil plate 100 often reaches a high temperature of 100 DEG C or more due to joule heat generated in the voice coil 11 at the time of operation of the loudspeaker, It is preferable to adopt a material having less strain. This is because when the base substrate 10 is thermally deformed in a narrow magnetic space, it may cause a defect in friction between the voice coil plate 100 and the magnetic body.

The base substrate 10 may have a chamfered corner 13. Heat generated during operation of the speaker is first accumulated in the voice coil plate 100 to raise the temperature. At this time, the degree of thermal expansion of each portion of the voice coil plate 100 may vary and cause thermal deformation. The largest displacement occurs when the thermal deformation occurs, and the portion directly contacting with the surrounding magnetic body is a corner portion farther from the diaphragm in the base substrate 10. Therefore, in the flat speaker according to the present embodiment, the corner portion 13 of the base substrate 10 is chamfered. With this structure, even if a slight thermal deformation occurs in the base substrate 10, the base substrate 10 can be prevented from contacting the surrounding magnetic body.

4 and 5 are enlarged views showing the corner portions of the voice coil plate in the flat type speaker according to the embodiments of the present invention. As described above, the corner portion of the base substrate 10 may be chamfered. For example, the corner portion 130 may be rounded with a predetermined radius of curvature. However, the shape of the corner portion is not limited to this, and can be variously modified. For example, as shown in FIG. 5, the corner portion 131 of the base substrate 10 may be formed in a shape such that a rectangular corner is cut into a triangle.

FIG. 6 is a cross-sectional view illustrating a cross-sectional voice coil plate and a diaphragm in a flat speaker according to an embodiment of the present invention. According to the present embodiment, the voice coil plate 101 may be a cross-sectional voice coil plate 101 having a voice coil 11 formed on one surface side of the base substrate 10. [ In this case, the heat radiating film 30 may be attached to both sides of the voice coil plate 101 as shown in the figure, or may be attached to only one side of the voice coil plate 101. The heat radiation film 30 may be attached to either side of the cross-sectional voice coil plate 101 on which the voice coil 11 is formed or on the opposite side. However, it is advantageous in terms of heat radiation efficiency to attach to the side where the voice coil 11 is formed.

FIG. 7 is a cross-sectional view showing a double-sided flat type voice coil plate and a diaphragm in a flat type speaker according to an embodiment of the present invention. The planar speaker according to the present embodiment includes a voice coil 11 formed on both sides of a base substrate 10 through conductive pattern printing and an insulating film 15 covering the surface of the voice coil 11. Although there is no restriction on the material of the insulating film 15, it may be formed of an organic insulating film in consideration of the process temperature and the like.

A heat radiation film (300) is attached to one surface of the voice coil plate (102). More specifically, the first region 310 of the heat dissipation film 300 is attached. The upper portion of the first region 310 is exposed to the outside of the diaphragm 20 through a through hole 21 formed in the diaphragm 20. A second area 320 of the heat dissipation film 300 is attached to the outer surface of the diaphragm 20. The second region 320 is attached so that a portion thereof is in direct contact with a portion of the first region 310.

Heat generated in the voice coil 11 is diffused through the first region 310 of the heat dissipation film 300 and transmitted to the second region 320 through the above structure. The second region 320 contacts the air outside the speaker and emits heat.

In this embodiment, a polyimide film having a size of 56 mm * 10 mm and a thickness of 0.2 mm is used as the base substrate 10, and a voice coil 11 having a length of 4 m, a volume of 360 mm 2, and a resistance value of 0.6? Respectively. A heat radiation film 300 having a first area 310 of 10 mm * 7 mm and an area of the second area 320 of 10 mm * 6 mm is formed of a graphene film having a thickness of 0.05 mm, Respectively. As a result of performing a thermal analysis under the condition of applying a current of 1A to the voice coil 11, when the heat radiation film 300 was not attached, the temperature of the voice coil plate 102 reached 198.8 ° C., It was confirmed that the film 300 was maintained at 103 캜.

8 shows simulation results of thermal stress and thermal deformation according to the case where the corner portions of the voice coil plate are chamfered and not chamfered in the flat speaker according to the above-described embodiment. As a result of employing the chamfered base film 10, neither of the two cases showed any thermal deformation to such an extent that it would come into contact with the surrounding magnetic body (with a gap of about 1.3 mm). However, when the corner portion is chamfered, it can be seen that the concentration of the thermal stress on the corner portion is eliminated. (A) the maximum displacement with respect to the upper end fixed to the diaphragm was 0.0372 mm, whereas (b) when the corner portion was chamfered at the temperature condition of 110 ° C, the maximum displacement was 0.0372 mm 0.0342mm.

10: base substrate
11: voice coil 13: base substrate corner part
20: diaphragm 21: diaphragm slit
30,300 heat radiation film 31, 310 heat radiation film first region
32, 320: heat radiation film second region 40: magnetic substance
41: permanent magnet 42: yoke plate
100, 101, 102: voice coil plate

Claims

A voice coil plate disposed in a magnetic space between a pair of magnetic bodies disposed at a predetermined interval from each other, the voice coil being formed on a planar base substrate surface side;
A diaphragm coupled to an upper end of the voice coil plate exposed to the outside of the magnetic space and vibrated by an electromagnetic force generated in the voice coil plate; And
And a heat radiating film made of a thermally conductive material and having a first region attached to the surface of the voice coil plate and a second region thermally connected to the first region and exposed to the outside of the vibration plate,
Flat-panel speakers.

The method according to claim 1,
The diaphragm has a through hole penetrating the inside toward the magnetic space and the outside opposite to the inside,
Wherein the first region and the second region of the heat dissipation film are thermally connected to each other through the through hole.
Flat-panel speakers.

The method of claim 2,
The heat-
Wherein the first region and the second region are made of one thermally conductive film continuous through the through hole.
Flat-panel speakers.

The method of claim 2,
The heat-
Wherein the first region and the second region are separated from each other and an upper end of the first region is exposed to the outside of the diaphragm through the through hole, And is attached to the outer surface of the diaphragm.
Flat-panel speakers.

The method according to claim 1,
Wherein the heat radiation film is a planar thermally conductive film having a thermal conductivity in the plane direction higher than a thermal conductivity in the thickness direction.
Flat-panel speakers.

The method according to claim 1,
Wherein the base substrate has a shape in which a corner portion farther from the diaphragm is chamfered.
Flat-panel speakers.

The method of claim 6,
Wherein the base substrate has a chamfered shape such that the corner portion is rounded with a predetermined radius of curvature.
Flat-panel speakers.

A voice coil plate disposed in a magnetic space between a pair of magnetic bodies disposed at a predetermined interval from each other, the voice coil being formed on a planar base substrate surface side; And
And a diaphragm coupled to an upper end of the voice coil plate exposed to the outside of the magnetic space and vibrated by an electromagnetic force generated in the voice coil plate,
Wherein the base substrate has a shape in which a corner portion farther from the diaphragm is chamfered.
Flat-panel speakers.