JP2008177692A - Electroacoustic transducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that an electrodynamic speaker in a thin and long shape used for compact portable equipment such as a mobile phone has trouble such as generation of an abnormal sound due to divisional vibrations in an intermediate frequency band during driving and deterioration in distortion rate since a voice coil is also in a thin and long shape such as a long circle shape and then has low strength at its long-edge side. <P>SOLUTION: In an electrodynamic electroacoustic transducer comprising a magnetic circuit comprising a permanent magnet, a yoke fixed to one magnetic pole side of the permanent magnet, and a top plate fixed to the other magnetic pole side, and a diaphragm having the voice coil, the voice coil is formed in the thin and long shape having long sides and short sides and a magnetic gap constituting the magnetic circuit is also formed in a thin and long shape having long sides and short sides, the short sides of the voice coil being connected by reinforcing members. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electroacoustic transducer, and more particularly to a conductive electroacoustic transducer including an elongated voice coil having a long side and a short side as a voice coil shape.

  In recent years, audio functions have been emphasized in small portable devices such as mobile phones. As electroacoustic transducers, electrodynamic electroacoustic transducers that emphasize acoustic characteristics from piezoelectric types that are intended only for call sounds are also available. It has come to be installed. Moreover, since these small portable devices take up space in the display device and the keyboard, the space for mounting the electroacoustic transducer is becoming narrower and the conventional circular electroacoustic transducer cannot be mounted.

  As a countermeasure, there is a configuration in which an elongated electroacoustic transducer is attached to avoid an enlarged display device in a cellular phone. (For example, refer to Patent Document 1).

  Hereinafter, the electroacoustic transducer in the prior art disclosed by patent document 1 is demonstrated using FIG. 12, FIG. FIG. 12 is a front view of a mobile phone provided with an electroacoustic transducer in the prior art disclosed in Patent Document 1, and FIG. 13 is a perspective view of a voice coil constituting the electroacoustic transducer of FIG. In FIG. 12, reference numeral 100 denotes a mobile phone. A lid 110 having a display device 111, a microphone 112, and a conductive speaker 60 that is an electroacoustic transducer, and a main body 120 having a keyboard 121 and function buttons 122 are hinge portions 130. It can be opened and closed.

  In the lid 110, the display device 111 for which a display screen that is as wide as possible occupies most of the area, and the elongated conductive speaker 60 is disposed in a narrow gap between the display device 111 and the hinge unit 130. Has been placed. FIG. 13 shows a voice coil 64 constituting the conductive speaker 60, and the shape of the voice coil 64 is rectangular according to the elongated shape of the conductive speaker 60. That is, the length L1 of the long side portion 64a of the voice coil 64 is an elongated shape that is twice or more the length L2 of the short side portion 64b.

Japanese Patent No. 3841222 (page 23, FIG. 26, FIG. 36)

  However, normally, the voice coil of the conductive speaker is generally circular. When the conductive speaker is driven, the balanced circular shape makes the stress applied to each part of the voice coil uniform, and a normal sound output can be generated.

  However, the voice coil 64 of the conductive speaker 60 in the cited document 1 has an elongated shape in which the ratio of the length L1 of the long side portion 64a to the length L2 of the short side portion 64b is twice or more. Due to this unbalanced shape when the type speaker is driven, there is a problem that the stress applied to each part of the voice coil becomes non-uniform and normal sound output cannot be generated. That is, due to insufficient strength of the long side portion 64a of the voice coil 64, inconveniences such as generation of abnormal sound due to divided vibration and deterioration of distortion rate occur in the middle frequency band.

(Object of invention)
The present invention has been made in view of the above problems, and has an elongated shape that can be disposed in a narrow space such as a portable device, while generating abnormal noise due to divided vibration in a middle frequency band, and deterioration of distortion rate. An object of the present invention is to provide an electroacoustic transducer in which occurrence of defects such as the above is improved.

  In order to achieve the above object, an electroacoustic transducer of the present invention comprises a permanent magnet, a yoke fixed to one magnetic pole side of the permanent magnet, a magnetic circuit comprising a top plate fixed to the other magnetic pole side, and a voice coil. In the electroacoustic transducer of the conductive type having the vibration film provided, the voice coil is formed in an elongated shape having a long side and a short side, and a magnetic gap constituting the magnetic circuit is also a long side and a short side The short side of the voice coil is connected by a reinforcing member.

  With the above configuration, by reinforcing the shortage of strength on the long side of the voice coil, it is possible to suppress the occurrence of abnormal sounds due to divided vibrations in the middle frequency band and the deterioration of distortion, and the acoustic characteristics Improved.

  The reinforcing member is attached to the upper surface of the voice coil, and is disposed on the lower surface side of the diaphragm.

  The magnetic circuit is provided with a slit in the vicinity of the central portion on the short side, and a reinforcing member attached to the lower surface side of the voice coil is housed in the slit.

  The magnetic circuit is divided into two by the slit.

  As described above, a three-dimensional reinforcing member that can be reinforced in the height direction of the voice coil is provided by providing a slit for storing a reinforcing member that vibrates when the electroacoustic transducer is driven at a position corresponding to the reinforcing member of the magnetic circuit. As a result, the acoustic characteristics were sufficiently improved.

  As described above, according to the electroacoustic conversion of the present invention, by reinforcing the shortage of strength on the long side of the voice coil, abnormal sound is generated due to divided vibration in the middle frequency band, and distortion is deteriorated. Can be suppressed, and the acoustic characteristics can be improved.

  Hereinafter, electroacoustic transducers according to embodiments of the present invention will be described in detail with reference to the drawings. 1 to 3 show a configuration of an electroacoustic transducer according to a first embodiment of the present invention. FIG. 1 is a cross-sectional view of the electroacoustic transducer, FIG. 2 is a top view of the electroacoustic transducer, and FIG. FIG. 3 is a perspective view of a voice coil of an electroacoustic transducer.

  1 and 2, reference numeral 10 denotes a conductive speaker that is an electroacoustic transducer, which has an elongated shape as with the conventional conductive speaker 60. 1 is a permanent magnet, 2 is a yoke fixed to one magnetic pole side of the permanent magnet 1, and 3 is a top plate fixed to the other magnetic pole side of the permanent magnet 1, and the permanent magnet 1, the yoke 2, and the top plate 3 A magnetic circuit is configured. Reference numeral 4 is a voice coil, and 5 is a reinforcing member that connects the short side of the voice coil 4. Details will be described later. Reference numeral 6 denotes a diaphragm provided with a voice coil 4, and 7 a frame. The frame 7 is connected to the yoke 2 to support the entire magnetic circuit. Reference numeral 8 denotes a protector which has a function of being coupled to the frame 7 to sandwich the vibration film 6 therebetween and protecting the upper surface side of the vibration film 6. The operation of the conductive speaker 10 is basically the same as that of the conventional conductive speaker. By energizing the voice coil 4 disposed in the magnetic gap 9 formed by the yoke 2 and the top plate 3, The vibrating membrane 6 vibrates and generates an acoustic output.

  FIG. 3 is a perspective view of the voice coil 4. Although the voice coil 4 has an oval shape, the length L1 of the long side 4a and the length L2 of the short side 4b are the same as those of the conventional voice coil 64. FIG. It has an elongated shape with a ratio twice or more. Therefore, when the conductive speaker is driven, the unbalanced shape causes the stress applied to each part of the voice coil to be non-uniform, and a normal sound output cannot be generated. In order to solve this problem in the present invention, a reinforcing member 5 for connecting the short side 4b of the voice coil 4 is provided. The reinforcing member 5 is configured to connect between the center positions of the long side portions 4a of the voice coil 4, and in the present embodiment, a lightweight and strong resin material is used. Specifically, a molded product of PPA (polyphthalamide) resin used for the frame 7 is bonded to the voice coil 4 using an acrylic UV adhesive, so that the voice coil 4 is formed by the thin plate-like reinforcing member 5. The upper surface side of is firmly connected. That is, the reinforcing member 5 is provided on the lower surface side of the vibration film 6 and is disposed in a space portion provided on the upper surface of the voice coil 4 and the lower surface side of the vibration film 6.

  By firmly connecting the short side portion 4b of the voice coil 4 with the reinforcing member 5 as described above, the strength shortage of the long side portion 4a in the voice coil 4 is improved, and abnormalities due to divided vibrations occur in the middle frequency band. Problems such as the generation of sound and deterioration of distortion no longer occur.

  Next, the configuration of the electroacoustic transducer according to the second embodiment of the present invention will be described with reference to FIGS. 4 is a cross-sectional view of the electroacoustic transducer, FIG. 5 is a top view of the electroacoustic transducer, and FIG. 6 is a perspective view of a voice coil of the electroacoustic transducer. 4 and 5, reference numeral 20 denotes a conductive speaker which is an electroacoustic transducer. The basic configuration is the same as that of the conductive speaker 10 of the first embodiment shown in FIG. 1, and the same elements are denoted by the same reference numerals. Thus, duplicate description is omitted.

  The conductive speaker 20 shown in FIGS. 4 and 5 is different from the conductive speaker 10 in that the permanent magnet is divided into two permanent magnets 1a and 1b, and the top plate is also divided into two top plates 3a, By being 3b, the magnetic circuit is divided into two near the central part on the long side, and a slit 21 is formed between them. The voice coil 14 is provided with a reinforcing member 25 on the inner surface side, and the reinforcing member 25 is accommodated in the slit 21.

  Here, the attachment structure of the reinforcing member 25 to the voice coil 14 will be described with reference to FIG. In the voice coil 4 shown in FIG. 3, the upper surface side of the voice coil 4 is firmly connected by a thin plate-like reinforcing member 5, whereas in the voice coil 14 in this embodiment, the inner surface side is formed by a three-dimensional reinforcing member 25. It is connected firmly. That is, since the three-dimensional reinforcing member 25 can reinforce the voice coil 14 in the height direction, the effect of improving the strength of the long side portion 14a in the voice coil 14 is extremely high.

  However, when a three-dimensional reinforcing member 25 is provided on the inner surface side of the voice coil 14 as shown in FIG. 4, the reinforcing member 25 is disposed at a position where it hits the top plate and the permanent magnet constituting the magnetic circuit. . In the present invention, in order to solve this problem, the magnetic circuit is divided into two to form the slit 21, and the reinforcing member 25 is accommodated in the slit 21. That is, when the voice coil 14 is energized and the diaphragm 6 vibrates and generates sound output, the three-dimensional reinforcing member 25 is also movable in the slit 21 in the same manner as the voice coil 14 is movable in the magnetic gap 9. It can be done. The reinforcing member 25 is formed of the same PPA resin as that of the reinforcing member 5 and is similarly bonded.

  Next, the configuration of the electroacoustic transducer according to the third embodiment of the present invention will be described with reference to FIGS. 7 is a cross-sectional view of the electroacoustic transducer, FIG. 8 is a top view of the electroacoustic transducer, and FIG. 9 is a perspective view of a voice coil of the electroacoustic transducer. 7 and 8, reference numeral 30 denotes a conductive speaker which is an electroacoustic transducer. The basic configuration is the same as that of the conductive speaker 10 of the first embodiment and the conductive speaker 20 of the second embodiment. Are given the same numbers, and duplicate descriptions are omitted.

  7 and 8 is different from the conductive speaker 20 in that the permanent magnet 1 is left as it is, and only the top plate is divided into two to form the top plates 3a and 3b. The portion is divided into two, and a slit 31 is formed between them. The voice coil 24 is provided with a reinforcing member 35 attached to one part of the upper surface and the inner surface thereof, and the reinforcing member 35 is accommodated in the slit 31.

  Here, the attachment structure of the reinforcing member 35 to the voice coil 24 will be described with reference to FIG. In the voice coil 14 shown in FIG. 4, the three-dimensional reinforcing member 25 reinforces the entire height of the voice coil 14, whereas in this embodiment, the three-dimensional reinforcing member is slightly thinner than the reinforcing member 25. 35, the upper surface of the voice coil 24 and a portion on the inner surface side are firmly connected. That is, the thickness of the three-dimensional reinforcing member 35 is reduced by the amount of the shallower slit 31 to avoid collision between the reinforcing member and the magnetic circuit.

  Next, the configuration of the electroacoustic transducer according to the fourth embodiment of the present invention will be described with reference to FIGS. 10 is a cross-sectional view of the electroacoustic transducer, and FIG. 11 is a top view of the electroacoustic transducer. 10 and 11, reference numeral 40 denotes a conductive speaker which is an electroacoustic transducer. The basic configuration is the same as that of the conductive speaker 20 of the second embodiment and the conductive speaker 30 of the third embodiment. Are given the same numbers, and duplicate descriptions are omitted.

  The conductive speaker 40 shown in FIG. 10 and FIG. 11 differs from the conductive speaker 30 in that the top plate is divided into two to form the top plates 3a and 3b, and a groove is provided in a part of the permanent magnet 1. One part of the magnetic circuit is divided into two, and a slit 41 is formed between them. The voice coil 34 has a reinforcing member 45 attached to a portion on the inner surface side thereof, and the reinforcing member 45 is accommodated in the slit 41.

  That is, the height of the reinforcing member 45 in the conductive speaker 40 is about half the height of the reinforcing member 25 in the conductive speaker 20, and the depth of the slit 41 is made shallower by that amount. As a result, the permanent magnet 1 can be left partly by grooving without completely separating the permanent magnet 1. The material and processing method of the reinforcing member 45 can be created in the same manner as the reinforcing member 25.

  As described above, since the electroacoustic transducer of the present invention reinforces the shortage of strength on the long side by connecting the short side of the elongated voice coil with the reinforcing member, the electroacoustic transducer uses split vibration in the middle frequency band. The generation of abnormal sounds and the deterioration of distortion rate can be suppressed, and the acoustic characteristics can be improved.

It is sectional drawing of the electroacoustic transducer in 1st Embodiment of this invention. It is a top view of the electroacoustic transducer in a 1st embodiment of the present invention. FIG. 3 is a perspective view of a voice coil in the electroacoustic transducer shown in FIGS. 1 and 2. It is sectional drawing of the electroacoustic transducer in 2nd Embodiment of this invention. It is a top view of the electroacoustic transducer in 2nd Embodiment of this invention. It is a perspective view of the voice coil in the electroacoustic transducer shown in FIG. 4, FIG. It is sectional drawing of the electroacoustic transducer in 3rd Embodiment of this invention. It is a top view of the electroacoustic transducer in 3rd Embodiment of this invention. It is a perspective view of the voice coil in the electroacoustic transducer shown in FIG. 7, FIG. It is sectional drawing of the electroacoustic transducer in 4th Embodiment of this invention. It is a top view of the electroacoustic transducer in 4th Embodiment of this invention. It is a front view of the mobile telephone provided with the electroacoustic transducer in a prior art. It is a perspective view of the voice coil which comprises the electroacoustic transducer of FIG.

Explanation of symbols

1, 1a, 1b Permanent magnet 2 Yoke 3, 3a, 3b Top plate 4, 14, 24, 34 Voice coil 5, 25, 35, 45 Reinforcing member 6 Vibration film 7 Frame 8 Protector 10, 20, 30, 40 Conductive type Speaker 21, 31, 41 Slit

Claims (4)

In a conductive electroacoustic transducer having a permanent magnet, a magnetic circuit made of a yoke fixed to one magnetic pole side of the permanent magnet, a top plate fixed to the other magnetic pole side, and a vibrating membrane provided with a voice coil, The voice coil is formed in an elongated shape having a long side and a short side, and a magnetic gap constituting the magnetic circuit is also formed in an elongated shape having a long side and a short side, and the short side of the voice coil is formed. An electroacoustic transducer having sides connected by a reinforcing member.
The electroacoustic transducer according to claim 1, wherein the reinforcing member is attached to an upper surface of the voice coil and is disposed on a lower surface side of the vibrating membrane.
2. The magnetic circuit is provided with a slit in the vicinity of the central portion on the long side, and a reinforcing member attached to the inner surface side of the voice coil is housed in the slit. Electroacoustic transducer.
The electroacoustic transducer according to claim 3, wherein the magnetic circuit is divided into two by the slit.

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