JP2009130666

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DESCRIPTION JP2009130666
An object of the present invention is to provide a conductive coil type speaker for use in a
portable telephone or the like. Since the voice coil is also elongated, the strength on the long side
of the voice coil is weak and divided vibration in the middle frequency band at the time of driving
Problems such as the generation of abnormal noise due to A conductive type electroacoustic
system having a magnetic circuit comprising a permanent magnet, 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 film provided with a voice coil. In the transducer, the vibrating membrane and the voice
coil are formed in an elongated shape having long sides and short sides, and a magnetic gap
forming the magnetic circuit is also formed in an elongated shape having long sides and short
sides. A step is formed in the direction of the short side of the vibrating membrane, and the side
wall of the voice coil is guided and reinforced on the side wall of the step. [Selected figure] Figure
1
Electro-acoustic transducer
[0001]
The present invention relates to an electroacoustic transducer, and more particularly to an
electroacoustic transducer of a conductive type provided with a voice coil having a long side and
a short side as a voice coil shape.
[0002]
In recent years, the audio function has been emphasized in small portable devices such as mobile
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phones, and as an electroacoustic transducer, an electrodynamic electroacoustic transducer that
emphasizes acoustic characteristics from a piezoelectric type aiming only for a simple call sound
has been developed. It has come to be installed.
Moreover, since these small portable devices take up space for display devices and keyboards,
the space for attaching the electroacoustic transducers is becoming narrower and smaller, and
the conventional circular electroacoustic transducers can not be attached. As a countermeasure
for this, there is a configuration in which an elongated electroacoustic transducer is attached to a
portable telephone avoiding a large-sized display device. (See, for example, Patent Document 1).
[0003]
Hereinafter, the electroacoustic transducer in the prior art disclosed in Patent Document 1 will be
described with reference to FIGS. 12 and 13. FIG. 12 is a front view of a mobile phone provided
with an electroacoustic transducer according to 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, and a display unit 111, a microphone
112, a cover 110 having a conductive speaker 60 which is an electro-acoustic transducer, and a
main unit 120 having a keyboard 121 and function buttons 122 are hinges 130. It is connected
so as to be openable and closable.
[0004]
In the lid portion 110, the display device 111 where a display screen as wide as possible is
desired occupies most of the area, and the elongated conductive speaker 60 is in the narrow gap
between the display device 111 and the hinge portion 130. It is arranged. FIG. 13 shows a voice
coil 64 constituting the conductive speaker 60. The shape of the voice coil 64 is rectangular in
accordance with the elongated shape of the conductive speaker 60. As shown in FIG. That is, the
length L1 of the long side 64a of the voice coil 64 is a slender shape which is twice or more the
length L2 of the short side 64b.
[0005]
Patent No. 38412222 (page 23, FIG. 26, FIG. 36)
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[0006]
However, generally, the voice coil of the conductive speaker is generally circular in shape.
The balanced circular shape at the time of driving the conductive speaker makes the stress
applied to each part of the voice coil uniform, so that a normal sound output can be generated.
[0007]
However, since the voice coil 64 of the conductive speaker 60 in Patent Document 1 has an
elongated shape in which the ratio of the length L1 of the long side 64a to the length L2 of the
short side 64b is twice or more, Due to this unbalanced shape when driving the type speaker,
there is a problem that the stress applied to each part of the voice coil becomes uneven, and a
normal sound output can not be generated. That is, due to the insufficient strength of the long
side portion 64a of the voice coil 64, problems such as generation of abnormal sound due to
divided vibration and deterioration of distortion factor occur in the middle frequency band.
[0008]
(Object of the Invention) The present invention has been made in view of the above problems,
and while having a slender shape capable of being disposed in a narrow space of a portable
device etc., generation of abnormal sound due to divided vibration in a mid frequency band It is
an object of the present invention to provide an electroacoustic transducer in which the
occurrence of defects such as deterioration in distortion rate is improved.
[0009]
An electroacoustic transducer according to the present invention for achieving the above object
comprises a magnetic circuit comprising a permanent magnet, a yoke fixed to one magnetic pole
side of the permanent magnet, a top plate fixed to the other magnetic pole side, and a voice coil.
In the electro-acoustic transducer of the conductive type having a vibrating membrane, the
vibrating membrane and the voice coil are formed in an elongated shape having a long side and a
short side, and a magnetic gap forming the magnetic circuit is also a long side. The step portion
is formed in the direction of the short side of the vibrating membrane, and the side surface of the
voice coil is guided and reinforced on the side wall of the step portion.
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[0010]
The stepped portion is characterized in that at least two are provided at both end portions in the
single side direction of the vibrating membrane.
[0011]
With the above configuration, by reinforcing the lack of strength on the long side of the voice
coil, it is possible to suppress the occurrence of abnormal sound due to divided vibration in the
middle frequency band and the occurrence of distortion rate deterioration. I was able to improve
it.
[0012]
The stepped portion is formed by a concave groove crossing a single side of the vibrating
membrane, and side walls of both ends of the concave groove are guided and reinforced on side
surfaces of the voice coil.
[0013]
A plurality of the step portions may be provided.
[0014]
The notch part for avoiding the said level ¦ step-difference part was provided in the position of
the top plate corresponding to the said level ¦ step-difference part.
[0015]
As described above, the height of the electroacoustic transducer is provided by providing a notch
at the position corresponding to the diaphragm step on the top plate constituting the magnetic
circuit, which accommodates the diaphragm step that vibrates when the electroacoustic
transducer is driven. Sufficient acoustic characteristics could be improved without increasing the
[0016]
As described above, according to the electro-acoustic conversion of the present invention,
generation of abnormal sound due to divided vibration in the middle frequency band and
generation of distortion rate deterioration by reinforcing the insufficient strength on the long
side of the voice coil Could be suppressed, and the acoustic characteristics could be improved.
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[0017]
Hereinafter, an electroacoustic transducer in an embodiment of the present invention will be
described in detail with reference to the drawings.
1 to 9 show the configuration of the electroacoustic transducer in the first embodiment of the
present invention, FIG. 1 is a top view of the electroacoustic transducer, and FIG. 2 is an A--of the
electroacoustic transducer of FIG. A is a sectional view, FIG. 3 is a B-B sectional view of the
electroacoustic transducer of FIG. 1, FIG. 4 is a top view of a vibrating membrane in the first
embodiment of the present invention, and FIG. 5 is an enlarged C-C sectional view of FIG. 6 is an
enlarged cross-sectional view of part G of FIG. 3, FIG. 7 is a top view of a magnetic circuit from
which the diaphragm is removed from the electroacoustic transducer of FIG. 1, and FIG. 8 is an
AA cross section of the magnetic circuit of FIG. FIG. 9 is a cross-sectional view of the magnetic
circuit of FIG. 7 taken along the line B-B.
[0018]
In FIG. 1, FIG. 2, and FIG. 3, reference numeral 10 denotes a conductive speaker which is an
electro-acoustic transducer, which has an elongated shape like 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,
3 is a top plate fixed to the other magnetic pole side of the permanent magnet 1, and the
permanent magnet 1, yoke 2 and top plate 3 It constitutes a magnetic circuit.
4 is a voice coil, 5 is a vibrating membrane provided with the voice coil 4, 6 is a concave shaped
groove formed to cross one side of the vibrating membrane, and the details will be described
later.
A frame 7 supports the entire magnetic circuit by being coupled with the yoke 2.
Reference numeral 8 denotes a protector, which has a function of protecting the upper surface
side of the vibrating membrane 5 while being combined with the frame 7 to hold the vibrating
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membrane 5 therebetween.
The operation of the conductive speaker 10 is basically the same as that of the conventional
conductive speaker, and by energizing the voice coil 4 disposed in the magnetic gap 9 formed by
the yoke 2 and the top plate 3. , And the diaphragm 5 vibrates to generate an acoustic output.
[0019]
Next, the concave groove 6 of the vibrating membrane 5, which is a feature of the present
invention, will be described.
As shown in FIGS. 4 and 5, the vibrating film 5 has a vibrating portion 5a curved at the center, a
flat coil bonding portion 5b for bonding a coil, and a supporting portion 5c held by the protector
8 and the frame 7. Are continuously formed in a ring shape from the center of the vibrating film
5.
The vibrating film 5 has an oval shape, and has an elongated shape in which the ratio of the
length L1 of the long side to the length L2 of the short side is twice or more.
[0020]
A recessed groove 6 is formed so as to cross a single side of the vibrating film 5, and the
recessed groove 6 is formed of a first groove 6a sunk one step from the vibrating portion 5a of
the vibrating film 5 and a first groove 6a. A second groove 6b sunk one step further is provided
at both ends, and the both ends of the second groove 6b form a step 6c to reinforce the voice coil
4.
The length of the concave groove 6 is equal to the width of the voice coil 4.
[0021]
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Next, the attachment and reinforcement configuration of the voice coil 4 to the diaphragm 5 will
be described with reference to FIG. FIG. 6 is an enlarged cross-sectional view of a portion G in
FIG. 3 and shows the attachment and reinforcement configuration of the voice coil 4 to the
vibrating membrane 5. FIG. 6 shows a state in which the voice coil 4 fixed to the vibrating film 5
is disposed in the magnetic gap 9 formed by the yoke 2 and the top plate 3 as described in FIG.
The attachment configuration of the voice coil 4 to the vibrating membrane 5 is such that the
upper side of the oval shaped voice coil 4 is bonded and fixed to the flat coil bonding portion 5 b
of the vibrating membrane 5 over the entire circumference. A part of the inner circumference of
the groove is guided by the side surface of the step portion 6c of the concave groove 6 provided
in the vibrating film 5 and reinforced. The guide of the voice coil 4 to the stepped portion 6c may
be pressure contact or may be adhered.
[0022]
That is, the attachment configuration of the voice coil 4 to the vibrating membrane 5 is
adhesively fixed to the coil bonding portion 5b indicated by hatching for easy understanding, and
a part of the inner periphery is reinforced by being guided to the side by the step portion 6c. ing.
The position where the voice coil 4 is guided by the step portion 6 c is optimally provided near
the center of the long side of the voice coil 4 in order to compensate for the lack of strength of
the long side of the voice coil 4.
[0023]
Next, the configuration of the magnetic circuit of the conductive speaker 10 will be described. 7
is a top view of a magnetic circuit in which the diaphragm 5 is removed from the conductive
speaker 10 of FIG. 1, FIG. 8 is a cross-sectional view of the magnetic circuit of FIG. 7 taken along
the line A-A, and FIG. 9 is a B-B of the magnetic circuit of FIG. It is sectional drawing, and attaches
¦ subjects only a number to each element same as the electroconductive type speaker 10 shown
to FIGS. 1-3, and it abbreviate ¦ omits the overlapping description.
[0024]
That is, as shown in FIGS. 7 and 9, the feature of the magnetic circuit of the present invention is
that the step 6c is formed at the position of the top plate 3 corresponding to the second groove
6b of the concave groove 6 formed in the vibrating film 5. The notch portions 3a and 3b for
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avoiding are provided, and the permanent magnet 1 is visible at the positions of the notch
portions 3a and 3b. Further, as shown in FIG. 6, a gap H in which the second groove 6b of the
concave groove 6 formed in the vibrating film 5 vibrates is secured by the notches 3a and 3b.
[0025]
10 and 11 show the configuration of a conductive speaker which is an electroacoustic transducer
according to a second embodiment of the present invention, FIG. 10 is a top view of the
conductive speaker, and FIG. 11 is a conductive speaker of FIG. It is AA sectional drawing of. The
conductive speaker 20 of FIGS. 10 and 11 has the same basic configuration as the conductive
speaker 10 in the first embodiment shown in FIGS. 1 and 2, and the same elements are denoted
by the same reference numerals and duplicate descriptions are omitted. Do.
[0026]
The place where the conductive speaker 20 is different from the conductive speaker 10 is that a
plurality of stepped portions are provided by forming two concave grooves 6 formed in the
vibrating film 5. That is, in the conductive speaker 10, one concave groove 6 is provided at the
central portion of the long side of the voice coil 4, while in the conductive speaker 20, two
concave grooves 6 are used as voices. That is, the coil 4 is provided at equal intervals from the
center of the long side of the coil 4. As a result, the side surface of the voice coil 4 is doubled in
the number of guide step parts, and reinforcement of the long side of the voice coil 4 It is
enhancing the effect.
[0027]
As described above, the electro-acoustic transducer according to the present invention reinforces
the lack of strength on the long side by guiding the short side of the elongated voice coil with the
step portion formed on the vibrating film, so that the middle frequency band It is possible to
suppress the generation of abnormal sound due to the divided vibration in the above and the
generation of the distortion rate deterioration, and the acoustic characteristics can be improved.
[0028]
It is a top view of an electroacoustic transducer in a 1st embodiment of the present invention.
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It is AA sectional drawing of the electroacoustic transducer shown in FIG. It is BB sectional
drawing of an electroacoustic transducer shown in FIG. It is a top view of a vibrating membrane
in a 1st embodiment of the present invention. FIG. 5 is an enlarged cross-sectional view of the
vibrating membrane shown in FIG. It is an expanded sectional view of the G section of the
electroacoustic transducer shown in FIG. It is a top view of the magnetic circuit which removed
the diaphragm from the electroacoustic transducer shown in FIG. It is AA sectional drawing of
the magnetic circuit shown in FIG. It is BB sectional drawing of the magnetic circuit shown in FIG.
It is a top view of the electroacoustic transducer in 2nd Embodiment of this invention. It is AA
sectional drawing of an electroacoustic transducer shown in FIG. 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 shown in FIG.
Explanation of sign
[0029]
DESCRIPTION OF SYMBOLS 1 permanent magnet 2 yoke 3 top plate 3a, 3b notch part 4 voice
coil 5 vibrating membrane 6 concave shape groove 6a 1st groove 6b 2nd groove 6c level
difference part 7 frame 8 protector 10, 20 conductive type speaker
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