JP2003032787A - Electric acoustic transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cause the entire diaphragm of an electric acoustic transducer to vibrate simultaneously and uniformly for widening the reproduction frequency band, and obtain excellent transient characteristics and flat sound pressure with less distortion without causing dindling. SOLUTION: A main diaphragm 72 is constituted of such a flat plate as to cover yokes 50 and 51 and top plates 52 to 54. Since the main diaphragm 72 has reinforcing members 75 to 78 extending substantially in the vertical direction, the main diaphragm is enhanced in strength. Therefore, when the electric acoustic transducer is driven by voice coils 74, the conversion efficiency (efficiency) is high and the transient characteristics are excellent despite of the relatively large mass of the main diaphragm 72. Since the strength of the diaphragm 72 is high, the diaphragm itself does not bend, parasitic oscillation and transverse oscillation are suppressed and the occurrence of dindling is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroacoustic conversion device for converting an electric signal into an acoustic signal such as a speaker, and more particularly to an electroacoustic device suitable for a flat panel speaker of a full drive type which vibrates the entire diaphragm at the same time. Regarding the converter.

[0002]

2. Description of the Related Art Generally, a full-face-drive type flat speaker is constructed so that the whole diaphragm vibrates back and forth uniformly in response to an electric signal supplied to a speaker terminal. An example of such a full-drive flat speaker is disclosed in Japanese Patent Publication No. 58-11158.

FIG. 1 is a cross-sectional view showing a schematic structure of a conventional flat panel type flat speaker. Square frame 10
A flat plate-shaped diaphragm 11 having a plurality of semi-cylindrical protrusions is arranged therein. The outer peripheral edge of the diaphragm 11 is oscillatably supported by the frame 10 via bellows-shaped support members 12 and 13 provided along the quadrangular shape of the frame 10. A plurality of semi-cylindrical protrusions provided on the surface of the diaphragm 11 are provided at regular intervals in a constant direction (vertical direction in the figure) via the support members 12 and 13, and a coated conductor to which a drive current is applied. The voice coil 14 is wound. The diaphragm 11 is a voice coil 14.
The diaphragm 11 is made of a polyimide (PI) film having excellent mechanical characteristics as the diaphragm 11.

A flat plate-shaped yoke 15 made of a metal plate such as iron is fixed to the rear surface (left bottom surface in the drawing) of the frame 10. Magnets 16 to 20 are fixed to the surface of the yoke 15 on the diaphragm 11 side, respectively, at the corresponding positions of the plurality of protrusions of the diaphragm 11. Pole pieces 21 to 25 made of iron or the like are provided on the upper surfaces of the magnets 16 to 20, respectively. The pole pieces 21 to 25 are fixed to the yoke 15 by brass studs.
The magnets 16 to 20 are fixed to the yoke 15 by 25. The pole pieces 21 to 25 are magnets 1
This is to concentrate the magnetic fluxes 6 to 20 near the voice coil 14. Yoke 15, magnets 16-20,
A magnetic circuit is configured by the pole pieces 21 to 25, the voice coil 14, and the like.

In the flat panel speaker having the above structure, when a driving current flows through the voice coil 14, an electromagnetic force corresponding to the magnitude of the driving current acts on the voice coil 14, and the electromagnetic force vibrates. The entire surface of the plate 11 vibrates in the left-right direction in the figure, and sound is generated in response to the vibration.

[0006]

In order to reduce the weight of the diaphragm 11 in the conventional all-surface-drive type flat speaker, the diaphragm itself is integrally molded, for example, to make the diaphragm itself as thin as possible. Therefore, the mechanical strength is structurally inferior depending on the shape of the diaphragm, and as a result, the entire diaphragm does not vibrate as a unit, and the diaphragm flexes, distorts, or vibrates in pieces. was there. Further, when the voice coil is driven by the drive current (audio signal), the diaphragm 11 vibrates in the direction perpendicular to the gap between the pole pieces 21 to 25 of the magnetic circuit due to the electromagnetic force acting on the voice coil 14. In addition, the diaphragm 11 is bent mainly because the strength of the diaphragm 11 is low, so that parasitic vibration occurs in the diaphragm 11 and, as a result, lateral vibration occurs in the voice coil 14. Therefore, there is a problem that the vibration becomes remarkable at a certain resonance frequency, and finally flicker occurs.

An object of the present invention is to obtain a wide reproduction frequency band by vibrating the entire diaphragm at the same time uniformly, and to obtain a flat sound pressure with excellent transient characteristics, low distortion, without causing flicker. An object is to provide an electroacoustic transducer capable of

[0008]

An electroacoustic transducer according to a first aspect of the present invention comprises a base plate means which is a part of a magnetic circuit, and a plurality of magnet means arranged on the base plate means at predetermined intervals in a predetermined direction. Between top plate means provided on the upper surface of each of the plurality of magnet means so as to form a predetermined magnetic gap in the predetermined direction and fixed to the base plate means together with the magnet means, and between the top plate means. A voice coil means which is disposed in at least one magnetic gap of the magnetic gaps formed in, and which is driven in response to the input of an electric signal; and a flat plate which entirely covers the top plate means. A reinforcing member extending substantially perpendicular to the face plate, fixedly having the voice coil means, A vibrating plate means that vibrates according to the driving force of the coil means; and a holding means that holds the vibrating plate means so that the vibrating plate means and the voice coil means vibrate without contacting the top plate means. It is a thing. In the electroacoustic transducer according to claim 1, the vibrating plate means is composed of a planar vibrating plate that entirely covers the top plate means, and the vibrating plate has a reinforcing member extending substantially vertically. The strength of the board itself is high. Therefore, by being driven by the voice coil means, the conversion efficiency (efficiency) as the electroacoustic conversion device is high and the transient characteristics are excellent even though the mass of the diaphragm is relatively large. Further, since the vibration plate itself has high strength, the vibration plate does not bend, parasitic vibration and lateral vibration are unlikely to occur in the vibration plate, and the occurrence of flicker can be suppressed. Also, since the voice coil is fixedly coupled to the high-strength diaphragm, there is no transmission loss, so the upper limit of its high-frequency characteristics is 30 [kHz].
It has reached the above, and has significantly higher performance than the same type of speaker.

An electroacoustic transducer according to a second aspect of the present invention is a base plate means which is a part of a magnetic circuit, a plurality of magnet means arranged on the base plate means at predetermined intervals in a predetermined direction, and a predetermined direction in the predetermined direction. A top plate means provided on the upper surface of each of the plurality of magnet means so as to form a magnetic gap and fixed to the base plate means together with the magnet means; and a combination of the magnet means and the top plate means. And a yoke means made of soft iron, which has substantially the same shape as the above, and is fixed to the base plate means so as to form the predetermined magnetic gap in the predetermined direction with respect to the outer two of the plurality of magnet means. A magnetic gap formed between the top plate means, the top plate means, and Disposed in at least one magnetic gap in the magnetic gap formed between the over click means,
Voice coil means driven in response to input of an electric signal,
A flat plate which entirely covers the top plate means and the yoke means, has a reinforcing member extending substantially perpendicular to the flat plate, and has the voice coil means fixedly, A diaphragm means that vibrates according to the driving force of the voice coil means, and holds the diaphragm means so that the diaphragm means and the voice coil means vibrate without contacting the top plate means and the yoke means. And holding means. This is because when a plurality of combinations of magnet means and top plate means are fixed to the base plate means at a predetermined interval, a new yoke means is formed so as to form a magnetic circuit for the two outside thereof. Is provided. Since the yoke means is provided so as to sandwich the magnet means, it functions to prevent the magnetic flux generated from the inner magnet means from leaking to the outside. Therefore, even if this electroacoustic transducer is placed near a CRT such as a television, the influence of magnetic flux can be suppressed.

The electroacoustic transducer according to a third aspect of the present invention is the electroacoustic transducer according to the first or second aspect, wherein the vibrating plate means is the flat plate, and a reinforcing member extending substantially vertically from one surface of the flat plate. The main diaphragm means has a main diaphragm means and a plurality of protrusions that individually cover the top plate means, and the voice coil means is fixedly wound around the protrusions. And sub-vibration means fixedly coupled to the means. This is a conventional high-strength main diaphragm means provided with a reinforcing member extending substantially perpendicularly to a flat plate in a sub-vibrating plate means in which voice coil means is wound around a semi-cylindrical projection. It is fixedly provided. As a result, the same effect as that of the electroacoustic transducer according to claim 1 can be obtained.

An electroacoustic transducer according to a fourth aspect is the electroacoustic transducer according to the first or second aspect, wherein the voice coil means is fixedly wound around a reinforcing member extending substantially perpendicular to the plane plate. Is. In this configuration, when the vibrating plate means is composed of only a flat plate, the reinforcing member is provided with the voice coil means. The reinforcing means functions to increase the strength of the diaphragm means made of a flat plate and also to hold the voice coil means in a fixed manner.

[0012]

FIG. 2 is a diagram showing a schematic configuration of an electroacoustic transducer according to an embodiment of the present invention.
It is the figure which showed the state where the frame and the supporting member were omitted from the upper surface. FIG. 3 is a sectional view taken along line XX of FIG.
FIG. 2 is a sectional view taken along line YY of FIG. 1. 5 is a diaphragm,
It is sectional drawing which shows the structure of the electroacoustic transducer provided with the frame and the support member, and is what corresponds to FIG.

As shown in FIG. 1, the base plate 30.
Is a part of a magnetic circuit, is made of a metal plate such as iron, and has a rectangular shape. Base plate 30
Is provided with a plurality of air vent holes 31 to 34, 35a to 35d, 36a to 36d for releasing back pressure inside the speaker. The air vent holes 31 to 34 are provided along the outer edge of the base plate 30. Air vent hole 35
A plurality of a to 35d and 36a to 36d are provided at equal intervals between the air vent hole 32 and the air vent hole 34. Magnets 41 to 43 are installed in parallel between the plurality of air vent holes 35a to 35d on the base plate 30 and between the plurality of air vent holes 36a to 36d, respectively.

The magnets 41 to 43 are made of prismatic neodymium magnets. Top plate 52 ~
The magnet 54 is provided on the upper surfaces of the magnets 41 to 43 so as to form a predetermined magnetic gap in the lateral direction of the drawing. In the figure, the magnets 41 to 43 and the top plate 5
The widths of 2 to 54 are almost the same, but the magnets 41 to 43 may be small. Screw holes are cut in both ends of the top plates 52 to 54, and are fixed by screws from the back side of the base plate 30 with screws 61 to 63 and 66 to 68. The polarities of the magnets 41 and 43 are S poles on the base plate 30 side and the N poles on the top plates 52 and 54, and the polarities of the magnets 42 are the opposite, the N poles on the base plate 30 side and the S poles on the top plate 53 side. That is, the magnets 42 are arranged so that the polarities of the magnets 42 are opposite to the polarities of the magnets 41 and 43 on both sides.

Soft iron yokes 50 and 51 are installed in parallel on both sides of the magnets 41 and 43. Screw holes are cut at both ends of the yokes 50, 51, and screws 60, 64, 65, 69 are inserted from the back side of the base plate 30.
It is fixed by screws. The shapes such as the width and height of the yokes 50 and 51 are the same as those in which the magnets 41 to 43 and the top plates 52 to 54 are combined.
The plurality of magnetic gaps formed between the yokes 50 and 51 and the top plates 52 to 54 are about 2 [m].
m]. The diaphragm 1 around which the voice coil 74 is wound.
It is desirable to form a magnetic gap that allows 1 to operate without contact. The voice coil 74 is placed in the magnetic gap so that the diaphragm 11 can be efficiently driven.

The magnetic circuit includes a base plate 30, magnets 41 to 43, top plates 52 to 54, and a yoke 5.
It is composed of 0,51. The yokes 50 and 51 at both ends of the members constituting this magnetic circuit prevent the magnetic flux generated from the magnets 41 to 43 from leaking to the outside. Conventionally, a magnet was also used in this part, but in that case there was a problem that the magnetic flux leaked to the outside, but by doing so, the leakage of the magnetic flux can be greatly reduced. It became so.

The diaphragm according to this embodiment has a double structure composed of a sub diaphragm 71 and a main diaphragm 72. The sub diaphragm 71 is molded with a plastic film so as to have a plurality of semi-cylindrical protrusions as in the conventional one, and a voice coil 74 is attached to the plurality of protrusions. Sub diaphragm 7
Main oscillating plate such as reinforced styrene plate or carbon fiber plate, which is attached to the upper side of 1 through light and durable reinforcing members (geta) 75-78 such as cypress thin plate or plastic. 72 is attached. That is, the main diaphragm 72 is formed by molding a light and highly rigid material such as a reinforced styrene plate or a carbon fiber plate. Inside the main diaphragm 72, a sub diaphragm 71, which serves as a holder for the voice coil 74 and is made of light and strong plastic, is bonded. Reinforcing member 75-7
8 has a structure like teeth of a geta extending substantially perpendicularly to the main diaphragm 72. By providing the reinforcing members 75 to 78, the strength (rigidity) of the main diaphragm 72 is increased.
Becomes higher, and deformation such as bending is suppressed. By making the diaphragm a double structure in this way, its strength can be significantly increased, the playback capability is high without flicker, and the entire band is excellent in sound quality with a wide band and low distortion. Speaker can be realized. Although the reinforcing members 75 to 78 are linearly provided in the figure,
This may be provided in a grid pattern. When the magnets 41 to 43, the top plates 52 to 54, and the yokes 50 and 51 are arranged in a lattice pattern, it is necessary to divide them according to the lattice pattern.

The edge portion holding the sub diaphragm 71 is made of Japanese paper and has a bellows-like sigma (Σ) type edge support member 7.
5, 76 are fixed to the inside of the frame 10 by double-sided tape. The bellows-shaped Σ type edge support members 75 and 76 are
An edge portion formed by folding a set of Japanese paper into a bellows shape is attached to both surfaces (upper surface and lower surface) of the outer peripheral portion of the sub diaphragm 71 with a double-sided tape or the like. The edge support members 75 and 76 are formed by cutting two rectangular Japanese papers with glue and pasting them together with glue to form a connecting ring, which is then folded into a quadrangle to have a Σ-shaped cross section. To be done. Double-sided tape is attached to both sides of the edge supporting members 75 and 76 thus created, and they are attached to the inside of the ABS resin frame 10 and the inside of the base plate 30. The diaphragm 72 is held. In this embodiment, a damper that is always attached to a normal speaker is not used. By eliminating this damper and holding it only by the bellows-shaped Σ-type edge support members 75 and 76, the low-range reproduction capability of the full-surface drive type flat panel speaker according to this embodiment is small even if the area of the diaphragm is small. regardless of,
Extremely high. In addition, as a result of actually measuring the whole surface drive type flat speaker, f0 (minimum resonance frequency) is about 40.
It was [Hz].

The voice coil 74 is wound for several turns after being continuously wound and adhered from the protruding portion of the sub diaphragm 71, which is formed by molding a plastic film to form a series of five semi-cylindrical protrusions. Five oval voice coils made by splitting and peeling each, and then folding it
It is formed by covering the protrusion of the sub diaphragm 71 and fixing it with an epoxy adhesive or the like. A formal wire of about 0.2Φ is used for the coil winding, and its impedance is about 4 to 8 [Ω]. The end of the voice coil is soldered to the two eyelets crimped on the sub diaphragm 71, and is further connected to the terminal attached to the base plate with the tinsel wire. Note that the number of voice coils may be the same as or smaller than the number of top plates.

In the above-described embodiment, the case where the diaphragm has a double structure composed of the sub diaphragm 71 and the main diaphragm 72 has been described. However, as shown in FIG. 6, the sub diaphragm is omitted, 2 separately on aluminum or Kent paper bobbins
The voice coil 84 that is heavily wound may be formed and bonded to the reinforcing members 85 to 88 of the diaphragm 82 via a holder that is formed by plastic molding. Although the voice coil 84 is directly wound around the reinforcing members 85 to 88 in FIG. 6, the reinforcing members 85 to 8 are actually used.
A bobbin is attached to the tip portion of 8. The reinforcing members 85 to 88 are formed like teeth of a geta extending substantially perpendicular to the diaphragm 82. This reinforcing member 85-88
By providing the, the strength (rigidity) of the diaphragm 82 is increased, and deformation such as bending is suppressed. A styrene support member 80 is adhered and fixed to the outer periphery of the diaphragm 82, and the edge support member 75,
The diaphragm 82 is supported by 76.

[0021]

As described above, according to the electroacoustic transducer of the present invention, by vibrating the entire diaphragm at the same time uniformly, a wide reproduction frequency band can be obtained, and a transient characteristic can be obtained without causing flicker. Excellent, low distortion and flat sound pressure can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a conventional full-surface-drive type planar speaker.

FIG. 2 is a diagram showing a schematic configuration of an embodiment of the electroacoustic transducer of the present invention.

3 is a cross-sectional view taken along line XX of FIG.

4 is a cross-sectional view taken along the line YY of FIG.

FIG. 5 is a cross-sectional view showing a configuration of an electroacoustic transducer including a diaphragm, a frame, and a support member.

6 is a cross-sectional view showing another embodiment of the electroacoustic transducer of FIG.

[Explanation of symbols]

10 ... Frame 11 ... Diaphragm 12, 13, 75, 76 ... Sigma type edge support member 14, 74 ... Voice coil 15, 30 ... Base plates 16-20, 41-43 ... Magnets 21-33, 52-54 ... Top plates 31-34, 35a-35d, 36a-36d ... Air vent holes 60-69 ... Screws 50, 51 ... Yoke 71 ... Sub diaphragm 72 ... Main diaphragm 75-78 ... Reinforcing member

Claims (4)

[Claims] 1. A base plate means which is a part of a magnetic circuit, a plurality of magnet means arranged on the base plate means at predetermined intervals in a predetermined direction, and a predetermined magnetic gap formed in the predetermined direction. Provided on the upper surface of each of the plurality of magnet means,
A top plate means fixed to the base plate means together with the magnet means, and a voice arranged in at least one of the magnetic gaps formed between the top plate means and driven according to the input of an electric signal. A coil means and a flat plate that entirely covers the top plate means, a reinforcing member extending substantially perpendicular to the flat plate, and a fixed voice coil means; A vibrating plate means that vibrates according to the driving force of the voice coil means; and a holding means that holds the vibrating plate means so that the vibrating plate means and the voice coil means vibrate without contacting the top plate means. An electroacoustic transducer characterized by being provided. 2. A base plate means which is a part of a magnetic circuit, a plurality of magnet means arranged on the base plate means at predetermined intervals in a predetermined direction, and a predetermined magnetic gap formed in the predetermined direction. Provided on the upper surface of each of the plurality of magnet means,
A top plate means fixed to the base plate means together with the magnet means; and a top plate means having substantially the same shape as a combination of the magnet means and the top plate means. A soft iron yoke means fixed to the base plate means so as to form the predetermined magnetic gap in the predetermined direction, a magnetic gap formed between the top plate means, the top plate means and the yoke means. A voice coil means disposed in at least one of the magnetic gaps formed between the top plate means and the yoke means, the voice coil means being driven according to an input of an electric signal; The reinforcing member is composed of a face plate and extends substantially perpendicular to the plane plate. A vibrating plate means that has a fixed coil means and that vibrates according to the driving force of the voice coil means; and vibrates without the vibrating plate means and the voice coil means contacting the top plate means and the yoke means. Holding means for holding the vibrating plate means. 3. The main vibrating plate means according to claim 1, wherein the vibrating plate means is the flat plate, and has a reinforcing member that extends substantially vertically from one surface of the flat plate. A sub-unit composed of a combination of a plurality of projecting portions for individually covering the plate means, the voice coil means being fixedly wound around the projecting portions, and fixedly connected to the main diaphragm means. An electroacoustic transducer comprising a diaphragm means. 4. The electroacoustic transducer according to claim 1, wherein the voice coil means is fixedly wound around a reinforcing member extending substantially perpendicularly to the plane plate.