Multifunction acoustic device

Details Multifunction acoustic device Multifunction acoustic device

2001-11-19

2003-10-28

Le, Huyen (Department: 2643)

Electrical audio signal processing systems and devices

Electro-acoustic audio transducer

Electromagnetic

C361S162000, C361S165000

Reexamination Certificate

active

06639992

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a multifunction acoustic device used in a portable instrument such as a portable telephone.
There has been provided an acoustic device of the portable instrument in which a speaker is provided for generating sounds of calling signals, and a vibrating motor is provided for informing the receiver of calling signals without generating sounds. In such a device, since both of the speaker and the motor are mounted in the device, the device is increased in size and weight, and in manufacturing cost.
In recent years, there is provided a multifunction acoustic device in order to remove the above described disadvantages. The multifunction acoustic device comprises a speaker having a vibrating plate and a permanent magnet magnetically connected to a voice coil mounted on the vibrating plate of the speaker. The permanent magnet is independently vibrated at a low frequency of 100-150 Hz so as to inform the receiving of calling signals by the vibration of the case of the device, which is transmitted to the body of the user of the device.
FIG. 6
is a sectional view of a conventional electromagnetic induction converter disclosed in Japanese Patent Laid Open 5-85192. The converter comprises a diaphragm
506
mounted in a case
512
at a periphery thereof, a voice coil
508
secured to the underside of a central portion
507
of the diaphragm
506
, a spring plate
511
mounted in the case
512
, and a permanent magnet
510
secured to a central portion of the spring plate
511
, inserted in the voice coil
508
.
By applying a low or high frequency signal to the voice coil
508
, the spring plate
511
is vibrated in the polarity direction Y of the magnet
510
.
In the device, the diaphragm
506
and the spring plate
511
are relatively moved through the magnetic combination between the voice coil
508
and the magnet
510
. Consequently, when a low frequency signal or a high frequency signal is applied to the voice coil
508
, both of the diaphragm
506
and the spring plate
511
are sequentially vibrated. As a result, sounds such as voice, music and others generated from the device are distorted, thereby reducing the quality of the sound. In addition, vibrating both of the voice coil
508
and the magnet
510
causes the low frequency vibration of the magnet to superimpose on the magnetic combination of the voice coil
508
and the magnet
510
, which further largely distorts the sounds.
FIG. 7
is a sectional view showing a conventional multifunction acoustic device. The device comprises a speaker vibrating plate
603
made of plastic and having a corrugated periphery
603
a
and a central dome, a voice coil
604
secured to the underside of the vibrating plate
603
at a central portion, and a magnet composition
610
. The vibrating plate
603
is secured to a frame
609
with adhesives.
The magnetic composition
610
comprises a lower yoke
605
, a core
601
formed on the yoke
605
at a central portion thereof, an annular permanent magnet
602
mounted on the lower yoke
605
, and an annular upper yoke
606
mounted on the permanent magnet
602
. The lower yoke
605
and the upper yoke
606
are resiliently supported in the frame
609
by spring plates
607
and
608
. A magnetic gap
611
is formed between a periphery
601
a
of the core
601
and an inside wall
606
a
of the upper yoke
606
to be magnetically connected to the voice coil
604
.
When an alternating voltage is applied to the voice coil
604
through input terminals
612
a
and
612
b
, the speaker vibrating plate
603
is vibrated in the direction Y to generate sounds at a frequency between 700 Hz and 5 KHz. If a low frequency signal or a high frequency signal is applied to the voice coil
604
, the speaker vibrating plate
603
and the magnetic composition
610
are sequentially vibrated, since the magnetic composition
610
and the speaker vibrating plate
603
are relatively moved through the magnetic combination of the voice coil
604
and the magnet composition
610
.
As a result, sounds such as voice, music and others generated from the device are distorted, thereby reducing the quality of the sound. In addition, the driving of both the voice coil
604
and the magnetic composition
610
causes the low frequency vibration to superimpose on the magnetic combination of the voice coil
604
and the magnetic composition
610
, which further largely distorts the sounds.
FIG. 8
is a sectional view showing another conventional multifunction acoustic device. The device comprises the speaker vibrating plate
603
made of plastic and having the corrugated periphery
603
a
and the central dome, the voice coil
604
secured to the underside of the vibrating plate
603
at a central portion, and the magnet composition
610
. The vibrating plate
603
is secured to the frame
609
with adhesives.
The magnetic composition
610
comprises a lower yoke
703
, core
601
formed on the yoke
703
at a central portion thereof, an annular permanent magnet
702
secured to the lower yoke
703
, and annular upper yoke
606
having a peripheral wall
606
b
and mounted on the permanent magnet
602
. The upper yoke
606
is resiliently supported in the frame
609
by spring plates
707
and
708
. A first magnetic gap
701
is formed between a periphery
601
a
of the core
601
and an inside wall of the upper yoke
606
to be magnetically connected to the voice coil
604
. A second gap
705
is formed between a periphery
703
a
of the lower yoke
703
and inside wall
606
a
of the upper yoke
606
. A driving coil
706
is secured to the frame and inserted in the second gap
705
.
When an alternating voltage is applied to the voice coil
604
through input terminals
612
a
and
612
b
, the speaker vibrating plate
603
is vibrated in the direction Y to generate sounds at a frequency between 700 Hz and 5 KHz. If a low frequency signal or a high frequency signal is applied to the voice coil
604
, the speaker vibrating plate
603
and the magnetic composition
610
are sequentially vibrated, since the magnetic composition
610
and the speaker vibrating plate
603
are relatively moved through the magnetic combination of the voice coil
604
and the magnet composition
610
.
When a high frequency signal for music is applied to the voice coil
604
, only the speaker vibrating plate
603
is vibrated. Therefore, there does not occur distortion of the sound. Furthermore, when a low frequency signal is applied to the driving coil
706
, only the magnetic composition
610
is vibrated, and the speaker vibrating plate
603
is not vibrated.
However if a high frequency signal is applied to input terminals
612
a
,
612
b
, and a low frequency signal is also applied to input terminals
704
a
,
704
b
, the speaker vibrating plate
603
and magnetic composition
610
are sequentially vibrated, thereby reducing the sound quality.
In the above described conventional devices, both the speaker vibration plate and the magnetic composition are vibrated when a low frequency signal or a high frequency signal is applied to the voice coil. This is caused by the reason that the low frequency vibrating composition is vibrated in the same direction as the high frequency vibrating direction.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a multifunction acoustic device in which a vibrating member is not vibrated together with another vibrating member, thereby removing disadvantages of conventional devices.
According to the present invention, there is provided a multifunction acoustic device comprising a frame, a speaker diaphragm supported in the frame, a voice coil secured to the speaker diaphragm, a rotor having a central permanent magnet and a cylindrical hub provided around the central permanent magnet, and rotatably supported in the frame, a motor annular permanent magnet disposed around the rotor, the voice coil being disposed in the gap formed between the central permanent magnet and the hub.
The rotor comprises an armature and a commutator.
The device further

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