JP2004032028A - Flat acoustic transducer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a flat acoustic transducer device capable of surely and easily arranging permanent magnets of correct polarity. <P>SOLUTION: Unmagnetized magnets 210-230, 310, 320 are attached to 1st and 2nd yokes 200, 300, these magnets 210-230, 310, 320 are magnetized in the directions different in each yoke, and then the 1st and 2nd yokes 200, 300 are assembled. Thus, the flat acoustic transducer device can be constituted and manufactured in magnet arrangement having polarities mutually different 180° by a simple process without confusing the magnetized polarities of the magnets on the yokes 200, 300. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a planar acoustic transducer in which a plurality of permanent magnets having different magnetic pole directions are mounted on a yoke.
[0002]
[Prior art]
2. Description of the Related Art In recent years, demand for flat-panel speakers has been increasing along with an increase in demand for flat-panel televisions. An acoustic transducer used for a flat speaker includes a flat yoke, permanent magnets mounted on the flat plate of the yoke, and alternately arranged with their magnetic pole directions inverted by 180 degrees, and a predetermined magnet above the permanent magnet. And a film-shaped diaphragm arranged with a gap between them. Since the permanent magnets on the yoke have different magnetic pole directions, the permanent magnets are magnetized to be permanent magnets before being arranged on the yoke at the manufacturing stage. Then, the permanent magnets are arranged and bonded on the yoke so that the magnetic pole direction matches the intended direction.
[0003]
[Problems to be solved by the invention]
However, according to the above-described prior art, when arranging and bonding the magnetized permanent magnets on the yoke, many man-hours are required and various troubles occur. That is, a plurality of permanent magnets having an attractive force are closely arranged in a target position on a yoke and in a target magnetic pole direction in close proximity to each other. Needed.
[0004]
In particular, when arranging the permanent magnets on the yoke, it is necessary to consider the direction of the magnetic poles, and further attention is required. However, the magnetic pole direction of the permanent magnet cannot be determined from the appearance, and the permanent magnet may be arranged in the wrong magnetic pole direction and bonded. Then, when an error was found after bonding, it was discarded as a defective part.
[0005]
From these facts, it is important how to realize a planar acoustic transducer in which permanent magnets having no error in the magnetic pole direction can be reliably and easily arranged on the yoke and manufactured.
[0006]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of the prior art, and a planar acoustic transducer capable of reliably and easily arranging permanent magnets having no error in the magnetic pole direction on a yoke and manufacturing the same. The purpose is to realize.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, a planar acoustic conversion device according to the invention of claim 1 includes a film-shaped diaphragm on which a coil pattern is formed, a plate-shaped yoke, A flat-type acoustic transducer having a plurality of permanent magnets having a magnetic pole direction perpendicular to the flat plate portion of the yoke and the magnetic pole directions being different by 180 degrees, wherein the yoke includes a permanent magnet having the same magnetic pole direction. It is characterized by comprising a first yoke mounted thereon and a second yoke mounted with a permanent magnet in a magnetic pole direction different from the magnetic pole direction by 180 degrees.
[0008]
According to the first aspect of the invention, the yoke mounts a permanent magnet having the same magnetic pole direction on the first yoke, and mounts a permanent magnet having a magnetic pole direction different by 180 degrees on the second yoke. Since the permanent magnets are to be placed, the permanent magnets are magnetized on the first or second yokes after the permanent magnets are placed on the yokes, and then the first and second yokes are united in different magnetizing directions. A yoke in which a plurality of permanent magnets having different magnetic pole directions are mounted easily and without erroneous magnetic pole directions can be manufactured as one flat yoke.
[0009]
The planar acoustic transducer according to the second aspect of the present invention is characterized in that the first and second yokes are provided with magnet position determining means for determining a position where the permanent magnet is mounted. I do.
[0010]
According to the second aspect of the present invention, since the first and second yokes determine the position where the permanent magnet is placed by the magnet position determining means, the permanent magnet is moved to the target position. Can be accurately placed and glued.
[0011]
Further, the planar acoustic transducer according to the invention of claim 3 is characterized in that the first and second yokes are provided with a yoke position determining means for determining a mutual position.
[0012]
According to the third aspect of the present invention, since the first and second yokes determine the mutual position by the yoke position determining means, the first and second yokes are combined when they are combined. , And the permanent magnets of each other can also be positioned at precise relative positions.
[0013]
In the flat acoustic transducer according to a fourth aspect of the present invention, the first and second yokes are provided with mounting means for mounting the permanent magnet at a position raised from the flat plate portion. Features.
[0014]
According to the fourth aspect of the present invention, the first and second yokes are mounted by the mounting means at a position where the permanent magnet is raised from the flat plate portion, so that the first and second yokes are generated by the permanent magnet. The magnetic field distribution can be improved, and the acoustic characteristics can be improved.
[0015]
A flat acoustic transducer according to a fifth aspect of the present invention is characterized in that a plurality of holes are provided in the flat portion of the first and second yokes.
According to the fifth aspect of the present invention, since the flat portions of the first and second yokes are provided with a plurality of holes, the back pressure when the diaphragm vibrates can be released, The acoustic characteristics can be improved.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a planar acoustic conversion device according to the present invention will be described with reference to the accompanying drawings. Note that the present invention is not limited to this.
[0017]
First, the overall configuration of the planar acoustic conversion device according to the present embodiment will be described. FIG. 1 is a diagram illustrating an overall configuration of a planar acoustic conversion device according to the present embodiment. First, the planar acoustic conversion device includes a diaphragm 100, a first yoke 200, a second yoke 300, and a plurality of permanent magnets (hereinafter, referred to as magnets). FIG. 1 shows a state where the first yoke 200 and the second yoke 300 are united and integrated. FIG. 1 also shows the cross sections of the first yoke 200 and the second yoke 300 in order to facilitate understanding of the structure.
[0018]
The first yoke 200 and the second yoke 300 are made of, for example, soft iron. Further, magnets 210 to 230 and magnets 310 and 320 are mounted on first yoke 200 and second yoke 300. The magnets 210 to 230 and the magnets 310 and 320 are, for example, square bar magnets made of neodymium magnets, and are arranged at equal intervals on the same XY coordinate plane in the drawing. The magnets 210 to 230 have N poles in the positive direction of the Z coordinate axis in the drawing, and the magnets 310 and 320 have a magnetic pole direction different from that of the magnets 210 to 230 by 180 degrees in the negative direction of the Z coordinate axis in the drawing. Has poles.
[0019]
In addition, the first yoke 200 and the second yoke 300 form a magnetic circuit that induces a magnetic flux generated by the magnets 210 to 230 and the magnets 310 and 320. Here, since the magnets 210 to 230 and the magnets 310 and 320 are alternately arranged, the magnetic field generated in the surrounding space by the magnet is periodic and has a magnetic field direction substantially parallel to the XY coordinate plane. Become. Note that the XYZ coordinate axes in FIG. 1 are set to be the same as the XYZ coordinate axes in FIGS. 2 and 4.
[0020]
The diaphragm 100 is formed of a film-shaped flexible printed board on which a coil pattern is formed. The diaphragm 100 is mounted on the first yoke 200 shown in FIG. 1 with a slight gap above the magnets 210 to 230 and the magnets 310 and 320. For example, when used as a speaker, an acoustic signal current flows through the coil pattern of the diaphragm 100, and interaction between the magnets 210 to 230 and the magnetic fields generated by the magnets 310 and 320 is caused by Lorentz force. Occurs. At this time, the diaphragm 100 vibrates due to the force generated in the coil pattern, and generates a sound wave.
[0021]
FIG. 2 shows a separated state before the first yoke 200 and the second yoke 300 are combined. Here, the detailed structures of the first yoke 200 and the second yoke 300 will be further described. The first yoke 200 includes a flat plate portion 280 and an enclosing portion 290, and first flat bases 270 to 272 on which a magnet is mounted are raised on the flat plate portion 280. In addition, there are ribs on the magnet mounting surfaces of the first frames 270 to 272. The rib is formed at a position sandwiching the magnet, and serves as a magnet position determining means for determining the magnet position in the Y-axis direction. Although the first yoke 200 has three first bases 270 to 272, they have exactly the same structure.
[0022]
In the flat plate portion 280 of the first yoke 200, a large number of first holes exist in the longitudinal direction of the magnet. All of these first holes have the same structure, and attenuate sound waves generated in the direction of the flat plate portion 280 by the diaphragm 100 to improve acoustic characteristics.
[0023]
In the second yoke 300, there are second bases 370 and 371 on which a magnet is mounted. The second mounts 370 and 371 and the first mounts 270 to 272 provide mounting means for mounting the magnets 310 and 320 and the magnets 210 to 230 with the bottom raised from the flat plate portion 280. Thereby, the magnetic fields generated by the magnets 310 and 320 and the magnets 210 to 230 are less likely to be magnetically affected by the flat plate portion 280 of the first yoke 200 made of soft iron, and are suitable for an acoustic transducer. .
[0024]
Also, the second mounts 370 and 371 have ribs, which have the same structure as the ribs of the first mount, and serve as magnet position determining means for determining the magnet position in the Y-axis direction. The second yoke 300 has side plates 380 and 381 which have a structure in which the side plates 380 and 381 are in close contact with the surrounding portion 290 of the first yoke 200, and determine the position of the second yoke 300 on the flat plate portion 280. Plays the role of position determination means.
[0025]
The second yoke 300 has second holes 360 to 362. When the second yoke 300 and the first yoke 200 are combined, the second holes 360 to 362 acoustically couple the plurality of first holes existing in the flat plate portion 280 of the first yoke 200. Prevent blocking.
[0026]
Next, an assembling process when the first yoke 200 and the second yoke 300 are combined to configure a planar acoustic transducer will be described. FIG. 3 is a flowchart illustrating these steps. First, non-magnetized magnets 310 and 320 are mounted on the second frames 370 and 371 of the second yoke 300 (step S301). At this time, the second base and the magnet are bonded to each other, and the structure of the second yoke 300 in FIG. 2 is obtained. Then, similarly, the non-magnetized magnets 210 to 230 are mounted on the first frame of the first yoke 200 (step S301).
[0027]
Thereafter, the second yoke 300 on which the unmagnetized magnets 310 and 320 are mounted is magnetized so that the negative direction of the Z axis becomes the N pole (step S303). Here, the magnets 310 and 320 of the second yoke 300 are magnetized in the magnetic pole direction shown in FIG. Then, similarly, the first yoke 200 on which the unmagnetized magnets 210 to 230 are mounted is magnetized so that the positive direction of the Z axis becomes the N pole (step S304). Here, the magnets 210 to 230 of the first yoke 200 are magnetized in the magnetic pole direction shown in FIG.
[0028]
Thereafter, the second yoke 300 and the first yoke 200 are united (step S305) to form an integrated yoke. Here, the integrated yoke is, as shown in FIG. 4C, a magnet in which every other magnetic pole direction has a direction different by 180 degrees and is arranged at regular intervals on the XY plane. Become.
[0029]
After that, the diaphragm 100 is mounted on the surrounding portion 290 of the first yoke 200 (Step S306), and the planar acoustic conversion device is completed, and the process ends.
As described above, in the present embodiment, the non-magnetized magnets 210 to 230, 310, and 320 are mounted on each yoke using the two yokes, the first yoke 200 and the second yoke 300. Then, the magnets are magnetized in different magnetic pole directions for each yoke, and then the first yoke 200 and the second yoke 300 are united to form an integrated yoke. With a simple and simple process, it is possible to form an array of magnets whose magnetic pole directions are alternately different by 180 degrees.
[0030]
Further, the planar acoustic conversion device according to the present embodiment can be used as a speaker or a microphone.
Further, in the present embodiment, the yoke and the magnet are arranged on one side of the film-shaped diaphragm, but similar magnetic circuits can be arranged on both sides of the film-shaped diaphragm.
[0031]
Further, in the present embodiment, a rod-shaped magnet is used, but the shape is not particularly limited. For example, a ring-shaped magnet may be used to make the same configuration.
[0032]
Further, in the present embodiment, the magnet and the magnet position determining means of the first and second yokes, and the yoke position determining means of the first and second yokes are provided with ribs and side plates, so that the Y-axis direction is provided. Is determined, but similarly, the position in the X-axis direction can be determined by providing a rib or a side plate in the X-axis direction. However, since the long direction of the magnet is the X-axis direction, the mounting accuracy is not required as high as the Y-axis direction.
[0033]
Further, in the present embodiment, the number of magnets is five. However, the number is not particularly limited as long as the number is an odd number and the direction of the magnetic pole is alternately reversed. The same can be applied to the magnetic pole direction even if the N pole and the S pole are all reversed.
[0034]
【The invention's effect】
As described above, according to the first aspect of the present invention, the yoke is such that the permanent magnets having the same magnetic pole direction are mounted on the first yoke and the magnetic pole directions having the magnetic pole directions different by 180 degrees on the second yoke. Since the permanent magnets are mounted on the first or second yoke, the permanent magnets are magnetized on each yoke after the permanent magnets are mounted on the first or second yoke. A yoke in which a plurality of permanent magnets having different magnetic pole directions are mounted can be manufactured easily and without a mistake in the magnetic pole direction by being united in the magnetic direction to form one flat yoke.
[0035]
According to the second aspect of the present invention, since the first and second yokes determine the position where the permanent magnet is placed by the magnet position determining means, the permanent magnet can be accurately positioned at the target position. Can be placed and glued.
[0036]
According to the third aspect of the invention, since the first and second yokes determine the mutual position by the yoke position determining means, when the first and second yokes are combined, It is possible to place them in precise positions with respect to one another and thus also the permanent magnets of each other in precise relative positions.
[0037]
According to the fourth aspect of the present invention, the first and second yokes are mounted by the mounting means at the position where the permanent magnet is raised from the flat plate portion, so that the magnetic field generated by the permanent magnet is provided. The distribution can be improved, and the acoustic characteristics can be improved.
[0038]
According to the fifth aspect of the present invention, since the plurality of holes are provided in the flat portions of the first and second yokes, the back pressure when the diaphragm vibrates can be released, and the acoustic pressure can be reduced. Characteristics can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a planar acoustic transducer.
FIG. 2 is a diagram showing first and second yokes of the embodiment.
FIG. 3 is a flowchart showing a manufacturing process of the embodiment.
FIG. 4 is a diagram showing a magnetizing direction of the magnet according to the embodiment.
[Explanation of symbols]
100 Vibration plate 200 First yoke 210, 220, 230 Magnet 270, 271, 272 First gantry 280 Flat plate portion 290 Surrounding portion 300 Second yoke 310, 320 Magnet 360, 361, 362 Second void 370, 371 second frame 380, 381 side plate

Claims (5)

A film-shaped diaphragm on which a coil pattern is formed,
A flat yoke,
A plurality of permanent magnets having a magnetic pole direction orthogonal to the flat plate portion of the yoke, wherein the magnetic pole directions are different by 180 degrees;
A planar acoustic conversion device comprising:
The yoke includes a first yoke on which a permanent magnet having the same magnetic pole direction is mounted, and a second yoke on which a permanent magnet having a magnetic pole direction different from the magnetic pole direction by 180 degrees is mounted. Flat sound transducer. 2. The flat acoustic transducer according to claim 1, wherein the first and second yokes include a magnet position determining unit that determines a position where the permanent magnet is placed. 3. 3. The flat acoustic transducer according to claim 1, wherein the first and second yokes include a yoke position determining unit that determines a mutual position. 4. The flat type according to any one of claims 1 to 3, wherein the first and second yokes include mounting means for mounting the permanent magnet at a position raised from the flat plate portion. Sound conversion device. 5. The flat acoustic transducer according to claim 1, wherein the first and second yokes have a plurality of holes in the flat plate portion.

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