WO2005055647A1

WO2005055647A1 - Plane speaker having closed loop coil plate

Info

Publication number: WO2005055647A1
Application number: PCT/KR2004/003155
Authority: WO
Inventors: Joung-Youl Shin; Byung-Wan Han
Original assignee: Joung-Youl Shin; Byung-Wan Han
Priority date: 2003-12-05
Filing date: 2004-12-02
Publication date: 2005-06-16
Also published as: KR100533714B1; KR20050055190A

Abstract

The present invention relates to a plate type speaker with a planar diaphragm. The plate type speaker comprises a concave base frame with an open top portion; at least one magnetic body coupled to the base frame such that opposite polarities are provided at adjacent lateral positions and are spaced apart by a predetermined distance from each other; a diaphragm; and a coil plate that is in the form of a plate with a voice coil wound on either or both of sides thereof, is formed to have a cross section thereof defining a closed loop and to be inserted into spaces between the opposite polarities of the magnetic body, and is connected to the diaphragm. The plate type speaker with the closed-loop shaped coil plate according to the present invention has advantages in that internal parts are compatible irrespective of the size and shape of the plate type speaker, and sound output and performance related thereto can be adjusted by modifying the shape and connection position of the coil plate even after the upper and lower plates and the permanent magnets have been completed.

Description

PLANE SPEAKER HAVING CLOSED LOOP COIL PLATE

Technical field The present invention relates to a plate speaker with a planar diaphragm, and more particularly, to a plate speaker with one or more juxtaposed coil plates around which voice coils are wound.

Background Art A speaker is a device for converting an electrical signal into a voice signal and is constructed such that a voice coil is driven, through a magnetic circuit comprising a permanent magnet, upper and lower plates and a center pole, to vibrate a diaphragm connected to the voice coil and to reproduce sound. A conventional plate type speaker will be described with reference to the accompanying drawings. Fig. 1 is a schematic sectional view of a conventional plate type speaker, and Fig. 2 is an exploded perspective view of a coupling structure of a voice coil, permanent magnets and plates employed in the conventional plate type speaker. As shown in Figs. 1 and 2, a coil plate 36 with a top end to which a flat diaphragm 30 is vertically fixed is inserted into an assembly of upper plates 31a, 31b, 31c, 31d, 32a, 32b, 32c and 32d, lower plates 33a, 33b, 33c, 33d, 34a, 34b, 34c and 34d, and permanent magnets 37 fixed therebetween. The assembly of permanent magnets and upper and lower plates is fixed to a base frame 35. Then, an edge 39 is bonded to the periphery of the flat diaphragm 30 and secured by a guide ring. An electric current generated at a speaker driving circuit is supplied to a voice coil 38 fixed at the coil plate 36 to produce a magnetic field at the voice coil 38. The magnetic field cooperates with a facing magnetic field generated from the polarity of the permanent magnet-plate assembly, thereby generating a force that vibrates the coil plate 36 and the flat diaphragm 30 fixed thereto. Consequently, the vibration of the diaphragm 30 causes sound to radiate outside. However, in the conventional plate type speaker constructed as above, it is required to additionally manufacture a pair of upper plates 31 and 32, a pair of lower plates

33 and 34, and the permanent magnets 37 depending on the size and shape of the diaphragm 30. Thus, there is a disadvantage in that existing parts that have already been produced cannot be reused. Further, since the conventional plate type speaker constructed as above does not allow changes in a connection position of the coil plate 36 after internal parts have been completed, there is a disadvantage in that output sound cannot be readjusted.

Disclosure

Technical Problem The present invention is conceived to solve the aforementioned problems. An object of the present invention is to provide a plate type speaker, wherein parts thereof are compatible irrespective of the size and shape of the plate type speaker, and a connection position of a coil plate can be changed even after upper and lower plates and permanent magnets have been completed.

Technical Solution According to the present invention for achieving the object, there is provided a plate type speaker, comprising a concave base frame with an open top portion; at least one magnetic body coupled to the base frame such that opposite polarities are provided at adjacent lateral positions and are spaced apart by a predetermined distance from each other; a diaphragm; and a coil plate that is in the form of a plate with a voice coil wound on either or both of sides thereof, is formed to have a cross section thereof defining a closed loop and to be inserted into spaces between the opposite polarities of the magnetic body, and is connected to the diaphragm. The polarities of the magnetic body may be successively arranged to form a closed loop. At this time, the overall arrangement shape of the polarities of the magnetic body may include a circle or a rectangle. A plurality of the magnetic bodies may be spaced apart from one another at a predetermined interval and each of the magnetic bodies may have opposite polarities at upper and lower ends thereof. At this time, each of the magnetic bodies may comprise a permanent magnet with opposite polarities at upper and lower ends thereof; an upper plate connected to the upper end of the permanent magnet; and a lower plate connected to the lower end of the permanent magnet and connected to a bottom surface of the base frame. Both opposite ends of the voice coil wound on either or both of the sides of the coil plate may be positioned at levels of the upper and lower ends of the magnetic bodies, respectively. The magnetic body may have opposite polarities at upper and lower ends thereof, the lower end may have an upwardly extending sidewall portion, an upper end of the sidewall portion may be spaced apart by a predetermined distance from an outer edge of the upper end of the magnetic body, and complementary horizontal concave and convex portions may be formed at the upper end of the sidewall portion of the magnetic body and at the upper end of the magnetic body, respectively, so that each convex portion is inserted into each concave portion with a predetermined gap therebetween. In this case, the magnetic body may comprise a permanent magnet with opposite polarities at upper and lower ends thereof; an upper plate connected to the upper end of the permanent magnet; and a lower plate that is connected to the lower end of the permanent magnet and connected to a bottom surface of the base frame and includes the sidewall portion extended upwardly. In the speaker, the base frame may comprise a coil plate recess formed in a portion of the bottom surface thereof corresponding to a lower end of the coil plate. At this time, the coil plate recess may be formed to be bored through the bottom surface of the base frame, at least one connection portion may be provided to partially connect a portion of the base frame inside the coil plate recess with a portion of the base frame outside the coil plate recess, and the connection portion may be formed not to interfere with the lower end of the coil plate when the lower end of the coil plate passes through the coil plate recess. h the speaker, the base frame may comprise one or more openings bored through a wall surface thereof.

Brief Description of Drawings Fig. 1 is a schematic sectional view of a conventional plate type speaker. Fig. 2 is an exploded perspective view of a coupling structure of a voice coil, permanent magnets and plates employed in the conventional plate type speaker. Fig. 3 is an exploded perspective view of a plate type speaker according to a first embodiment of the present invention. Fig. 4 is a plan view showing a coupled configuration of a coil plate and magnetic bodies shown in Fig. 3. Fig. 5 is a longitudinal sectional view of the plate type speaker of according to the first embodiment of the present invention. Fig. 6 illustrates a modified example in which the arrangement of the magnetic bodies and the shape of the coil plate in the first embodiment are changed. Fig. 7 illustrates a further modified example in which the arrangement of the magnetic bodies and the shape of the coil plate in the first embodiment are changed. Fig. 8 illustrates a coupled configuration of a magnetic body and a coil plate in a modified example in which the shape of the magnetic body is changed. Fig. 9 is a sectional view taken along line A- A shown in Fig. 8. Fig. 10 is an exploded perspective view of a plate type speaker according to a second embodiment of the present invention. Fig. 11 is a plan view showing a coupled configuration of a coil plate and magnetic bodies shown in Fig. 10.

Best Mode for Carrying out the Invention Hereinafter, preferred embodiments of a plate type speaker with a closed-loop shaped coil plate according to the present invention will be described with reference to the accompanying drawings. Fig. 3 is an exploded perspective view of a plate type speaker according to a first embodiment of the present invention, and Fig. 4 is a plan view showing a coupled configuration of a coil plate and magnetic bodies shown in Fig. 3. As shown in Figs. 3 and 4, a plate type speaker with a closed-loop shaped coil plate according to the present invention comprises a concave base frame 100 with an open top portion; a plurality of magnetic bodies 200 that generate magnetic fields of different polarities at upper and lower portions thereof and are connected to a bottom surface of the base frame 100; a diaphragm 300 in the form of a plate with an area that allows the diaphragm to be inserted into the base frame 100; and a coil plate 400 connected to a lower end surface of the diaphragm 300 at an angle which allows the coil plate 400 to be inserted into spaces between the magnetic bodies 200. Each of the magnetic bodies 200 comprises a permanent magnet 210 with a size insertable into the base frame 100 and with opposite polarities at upper and lower ends thereof; an upper plate 220 that is in the form of a panel made of a magnetic material and having a size capable of covering the upper end of the permanent magnet 210 and is in close contact with the upper end of the permanent magnet 210; and a lower plate 230 that is formed in the same manner as the upper plate 220 in material and size and is in close contact with the lower end of the permanent magnet 210 while being connected to the bottom surface of the base frame 100. Accordingly, the upper plate 220 will have the same polarity as the upper end of the permanent magnet 210, and the lower plate 230 will have the same polarity as the lower end of the permanent magnet 210. Further, the magnetic bodies 200 are juxtaposed at a predetermined interval in a direction orthogonal to a longitudinal direction. In addition, the magnetic bodies 200 are connected to the base frame 100 in a state where adjacent magnetic bodies are inverted with respect to each other so that the polarities at the upper and lower ends thereof alternately appear. Thus, attractive forces are produced between the respective magnetic bodies 200. The diaphragm 300 is made in the form of a plate with an area that allows the diaphragm 300 to be inserted into the base frame 100. A bonding member 310, which extends outwardly parallel to an upper end surface of the diaphragm 300, is provided at an outer periphery of the diaphragm 300, so that the bonding member can be connected to a top portion of the base frame 100. At this time, the bonding member 310 is made of a flexible material such as fabric or paper so that the diaphragm 300 can vertically vibrate while being kept in a state of connection with the base frame 100. Further, the diaphragm 300 is formed to have an area smaller than that of the opening defined in the top portion of the base frame 100 so that the diaphragm 300 does not interfere with the base frame 100 even though the diaphragm 300 vibrates vertically. Since the material and structure of the diaphragm 300 are the same as a diaphragm employed in a conventional plate type speaker, a detailed description thereof will be omitted. The coil plate 400 is made in the form of a plate with a closed-loop shape in cross section such that the coil plate 400 can be inserted into spaces between the magnetic bodies 200 without contact with the magnetic bodies 200. The cross sectional shape of the coil plate 400 is determined according to intervals between the magnetic bodies 200. In this embodiment, since there are straight intervals between the respective magnetic bodies 200, the cross sectional shape of the coil plate 400 becomes a closed polygonal shape. Further, a voice coil 410 is coupled to one side of the coil plate 400 while being wound along an outer periphery of the coil plate 400. At this time, the voice coil 410 is wound in the form of a track with horizontal upper and lower ends. The coil plate 400 is coupled such that the upper and lower ends of the voice coil 410 are positioned between the upper plates 220 and between the lower plates 230, respectively. If the size of the plate type speaker according to the present invention is intended to increase, the plate type speaker can enlarge only by increasing the number of the magnetic bodies 200 without additionally manufacturing new magnetic bodies 200. Thus, there is no limitation on enlargement of the plate type speaker of the present invention. Further, the base frame 100 has a downwardly concave coil plate recess 110 formed in a portion of the base frame 100 corresponding to the lower end of the coil plate 400, so that the coil plate 400 does not come into contact with the bottom surface of the base frame 100 upon vertical vibration of the coil plate. The concave coil plate recess 110 is formed to have a width larger than the thickness of the coil plate 400, and a depth determined according to a vibrating distance of the coil plate 400. If the vibrating distance of the coil plate 400 is large, the coil plate recess 110 may be formed to be bored through the bottom surface of the base frame 100. In this case, however, because the coil plate recess 110 is formed in the portion of the base frame corresponding to the lower end of the coil plate 400 defining a closed loop, a portion of the base frame 100 inside the coil plate recess 110 is separated from a portion of the base frame 100 outside the coil plate recess 110 and thus cannot support some of the magnetic bodies 200. To solve this problem, at least one connection portion (not shown) may be provided to partially connect the portion of the base frame 100 inside the coil plate recess 110 with the portion of the base frame 100 outside the coil plate recess 110. The connection portion should be formed not to interfere with the lower end of the coil plate 400 when the lower end of the coil plate 400 protrudes beyond the bottom surface of the base frame 100. For example, a plurality of "U"-shaped connection portions may be attached to an outer bottom surface of the portion of the base frame 100 inside the coil plate recess 110 and to an outer bottom surface of the portion of the base frame 100 outside the coil plate recess 110. Alternatively, the base frame 100 may be manufactured such that a plurality of "U"-shaped connection portions are integrally formed on the outer bottom surface of the base frame 100. Further, the base frame 100 is formed with at least one side opening 120 bored through a sidewall thereof so that air flows inward or outward when the top opening of the base frame 100 is hermetically closed by the diaphragm 300. If a side opening 120 is not formed in the base frame 100, pressure within the base frame 100 increases when the diaphragm 300, which is connected to and hermetically closes the top portion of the base frame 100, vibrates vertically. Accordingly, the diaphragm 300 cannot normally vibrate only with an electric current and a magnetic flux and is affected by the air pressure within the base frame 100. However, if side openings 120 are formed in the base frame 100 like the embodiment shown in Fig. 3, the pressure within the base frame 100 does not vary and thus the diaphragm 300 normally vibrates only by the current and the magnetic flux. Fig. 5 is a longitudinal sectional view of the plate type speaker of according to the first embodiment of the present invention. As shown in Fig. 5, the coil plate 400 is kept in non-contact with the magnetic bodies 200 and is inserted into spaces between the magnetic bodies 200. The diaphragm 300 is coupled not to interfere with the base frame 100 and the magnetic bodies 200 upon vertical vibration of the diaphragm. Further, the coil plate recess 110 is formed in the portion of the bottom surface of the base frame 100, which corresponds to the lower end of the coil plate 400 when the diaphragm 300 and the coil plate 400 are coupled to the base frame 100. Accordingly, since there is no contact between the coil plate 400 and the base frame 100 even though the amplitude of the vertical vibration of the diaphragm 300 becomes larger, the diaphragm 300 can normally vibrate without external interference. Fig. 6 illustrates a modified example in which the arrangement of the magnetic bodies and the shape of the coil plate in the first embodiment are changed. A plate type speaker having a closed-loop shaped coil plate according to the present invention is constructed to have a structure in which the shape and performance of the plate type speaker can be changed more easily as compared to a conventional plate type speaker. For example, when the diaphragm 300 is required to have a larger vibration force as compared with the case shown in Fig. 4, the performance of the plate type speaker can be adjusted by modifying only the shape of the coil plate 400 and the arrangement of the magnetic bodies 200, as shown in Fig. 6. Further, since the shape of the diaphragm 300 can be modified through only modification of the arrangement of the magnetic bodies 200 without modifying the shapes of the magnetic bodies, a manufacturer can use the magnetic bodies 200 in common when the modification of the shape of the diaphragm 300 is required, so that a manufacturing process can be simplified and production costs can be reduced. Fig. 7 illustrates a further modified example in which the arrangement of the magnetic bodies and the shape of the coil plate in the first embodiment are changed. A plate type speaker with a closed-loop shaped coil plate according to the present invention may be constructed to have a simpler structure by reducing the number of the magnetic bodies 200 employed therein. If the shapes of the magnetic bodies 200 are modified as shown in Fig. 7, the coil plate 400 of the example shown in Fig. 6 can be used as it is, and the number of the employed magnetic bodies 200 can be reduced. When the number of the magnetic bodies 200 is reduced, there are advantages in that the inner configuration can be simplified, production of products can be facilitated, production costs can be reduced, and the design of a circuit and a mechanism can be flexible. Fig. 8 illustrates a coupled configuration of a magnetic body and a coil plate in a modified example in which the shape of the magnetic body is changed, and Fig. 9 is a sectional view taken along line A- A shown in Fig. 8. As shown in Figs. 8 and 9, in the magnetic body 200 employed in the present invention, an upper plate 220 and a lower plate 230 are connected to upper and lower ends of a permanent magnet 210, respectively, wherein the permanent magnet 210 has opposite polarities at the upper and lower ends thereof. The lower plate 230 is formed to extend outwardly as compared to the upper plate 220. Further, the lower plate 230 has an upwardly extending sidewall portion 235 at a distal end of the extension of the lower plate 230. The sidewall portion 235 is formed to be spaced apart by a predetermined distance from an outer edge of the upper plate 220. In particular, as shown in Fig. 8, complementary horizontal concave and convex portions are formed at an upper end of the sidewall portion 235 and the upper plate 220, and each convex portion is inserted into each concave portion with a predetermined gap therebetween. At this time, the coil plate 400 is coupled to a lower end surface of a diaphragm

(not shown) at an angle that allows the coil plate 400 to be inserted into a space between the upper plate 220 and the sidewall portion 235 of the lower plate 230. Since this modification of the shape of the magnetic body 200 allows the coil plate

400 to vibrate vertically using a single magnetic body 200, there is an advantage in that the inner configuration and the manufacturing process of the product can be simplified. Since the shapes and structures of the base frame and the diaphragm can be employed in the same manner as those of other embodiments, detailed descriptions thereof will be omitted. Fig. 10 is an exploded perspective view of a plate type speaker according to a second embodiment of the present invention, and Fig. 11 is a plan view showing a coupled configuration of a coil plate and magnetic bodies shown in Fig. 10. As shown in Fig. 10, the plate type speaker with a closed-loop shaped coil plate according to the present invention is also applicable to a plate type speaker with a circular diaphragm 300'. If the diaphragm 300' is formed to take the shape of a circle, a plurality of magnetic bodies 200' are circumferentially arranged to be spaced apart from one another at a predetermined interval. Further, the coil plate 400' is formed to be inserted into spaces between the magnetic bodies 200' and to be connected to a lower end surface of the diaphragm 300'. At this time, as for the magnetic bodies 200' employed in the second embodiment, the magnetic bodies 200 employed in the first embodiment may be used as they are.

Alternatively, both sides of each of the magnetic bodies 200' may be formed to define an angle therebetween, as shown in Figs. 10 and 11. If the both sides of each of the magnetic bodies 200' are formed to define the angle therebetween as shown in Figs. 10 and 11, the sides of each of magnetic bodies 200' become parallel to the sides of an adjacent one of the magnetic bodies 200'. Thus, there is an advantage in that a uniform magnetic field is generated between the magnetic bodies 200'. Since the operation of the plate type speaker according to the second embodiment is the same as the plate type speaker according to the first embodiment, a detailed description thereof will be omitted. Although the present invention has been specifically described in connection with the preferred embodiments, the scope of the present invention is not limited to the specific embodiments but should be construed based on the appended claims. Further, it will be understood by those skilled in the art that various modifications and variants can be made to the present invention without departing from the scope and sprit of the present invention. For example, a groove may be formed in a coil plate to be bored therethrough so that a voice coil is wound on one side of the coil plate and then is wound on the other side thereof after passing through the groove.

Industrial Applicability The plate type speaker with the closed-loop shaped coil plate according to the present invention has advantages in that internal parts are compatible irrespective of the size and shape of the plate type speaker, and sound output and performance related thereto can be adjusted by modifying the shape and connection position of the coil plate even after the upper and lower plates and the permanent magnets have been completed.

Claims

1. A plate type speaker, comprising: a concave base frame with an open top portion; at least one magnetic body coupled to the base frame such that opposite polarities are provided at adjacent lateral positions and are spaced apart by a predetermined distance from each other; a diaphragm; and a coil plate in the form of a plate with a voice coil wound on either or both of sides thereof, the coil plate being formed to have a cross section thereof defining a closed loop and to be inserted into spaces between the opposite polarities of the magnetic body, the coil plate being connected to the diaphragm.

2. The speaker as claimed in claim 1, wherein the polarities of the magnetic body are successively arranged to form a closed loop.

3. The speaker as claimed in claim 2, wherein the overall arrangement shape of the polarities of the magnetic body includes a circle or a rectangle.

4. The speaker as claimed in any one of claims 1 to 3, wherein a plurality of the magnetic bodies are spaced apart from one another at a predetermined interval, each of the magnetic bodies having opposite polarities at upper and lower ends thereof.

5. The speaker as claimed in claim 4, wherein each of the magnetic bodies comprises: a permanent magnet with opposite polarities at upper and lower ends thereof; an upper plate connected to the upper end of the permanent magnet; and a lower plate connected to the lower end of the permanent magnet and connected to a bottom surface of the base frame.

6. The speaker as claimed in claim 4, wherein both opposite ends of the voice coil wound on either or both of the sides of the coil plate are positioned at levels of the upper and lower ends of the magnetic bodies, respectively.

7. The speaker as claimed in claim 1, wherein the magnetic body has opposite polarities at upper and lower ends thereof, the lower end has an upwardly extending sidewall portion, an upper end of the sidewall portion is spaced apart by a predetermined distance from an outer edge of the upper end of the magnetic body, and complementary horizontal concave and convex portions are formed at the upper end of the sidewall portion of the magnetic body and at the upper end of the magnetic body, respectively, so that each convex portion is inserted into each concave portion with a predetermined gap therebetween.

8. The speaker as claimed in claim 7, wherein the magnetic body comprises: a permanent magnet with opposite polarities at upper and lower ends thereof; an upper plate connected to the upper end of the permanent magnet; and a lower plate connected to the lower end of the permanent magnet and connected to a bottom surface of the base frame, the lower plate including a sidewall portion extended upwardly.

9. The speaker as claimed in any one of claims 1 to 3 and 7 and 8, wherein the base frame comprises a coil plate recess formed in a portion of the bottom surface thereof corresponding to a lower end of the coil plate.

10. The speaker as claimed in claim 9, wherein the coil plate recess is formed to be bored through the bottom surface of the base frame, at least one connection portion is provided to partially connect a portion of the base frame inside the coil plate recess with a portion of the base frame outside the coil plate recess, and the connection portion is formed not to interfere with the lower end of the coil plate when the lower end of the coil plate passes through the coil plate recess.

11. The speaker as claimed in any one of claims 1 to 3 and 7 and 8, wherein the base frame comprises one or more openings bored through a wall surface thereof.