Multifunction acoustic device

Details Multifunction acoustic device Multifunction acoustic device

2001-09-06

2004-06-01

Kuntz, Curtis (Department: 2643)

Electrical audio signal processing systems and devices

Electro-acoustic audio transducer

Electromagnetic

C381S162000, C381S421000

Reexamination Certificate

active

06744904

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. 7
is a sectional view of a conventional electromagnetic induction converter disclosed in Japanese Patent Laid Open 5-85192. The converter comprises a diaphragm
606
mounted in a case
612
at a periphery thereof, a voice coil
609
secured to the underside of a central portion
607
of the diaphragm
606
, a spring plate
611
mounted in the case
612
, and a permanent magnet
610
secured to a central portion of the spring plate
611
, inserted in the voice coil
609
.
By applying a low or high frequency signal to the voice coil
609
, the spring plate
611
is vibrated in the polarity direction Y of the magnet
610
.
In the device, the diaphragm
606
and the spring plate
611
are relatively moved through the magnetic combination between the voice coil
609
and the magnet
610
. Consequently, when a low frequency signal or a high frequency signal is applied to the voice coil
609
, both of the diaphragm
606
and the spring plate
611
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
609
and the magnet
610
causes the low frequency vibration of the magnet to superimpose on the magnetic combination of the voice coil
609
and the magnet
610
, which further largely distorts the sounds.
FIG. 8
is a sectional view showing a conventional multifunction acoustic device. The device comprises a speaker vibrating plate
703
made of plastic and having a corrugated periphery
703
a
and a central dome, a voice coil
704
secured to the underside of the vibrating plate
703
at a central portion, and a magnet composition
710
. The vibrating plate
703
is secured to a frame
709
with adhesives.
The magnetic composition
710
comprises a lower yoke
705
, a core
701
formed on the yoke
705
at a central portion thereof, an annular permanent magnet
702
mounted on the lower yoke
705
, and an annular upper yoke
706
mounted on the permanent magnet
702
. The lower yoke
705
and the upper yoke
706
are resiliently supported in the frame
709
by spring plates
707
and
708
. A magnetic gap
711
is formed between a periphery
701
a
of the core
701
and an inside wall
706
a
of the upper yoke
706
to be magnetically connected to the voice coil
704
.
When an alternating voltage is applied to the voice coil
704
through input terminals
712
a
and
712
b
, the speaker vibrating plate
703
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
704
, the speaker vibrating plate
703
and the magnetic composition
710
are sequentially vibrated, since the magnetic composition
710
and the speaker vibrating plate
703
are relatively moved through the magnetic combination of the voice coil
704
and the magnet composition
710
.
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
704
and the magnetic composition
710
causes the low frequency vibration to superimpose on the magnetic combination of the voice coil
704
and the magnetic composition
710
, which further largely distorts the sounds.
FIG. 9
is a sectional view showing another conventional multifunction acoustic device. The device comprises the speaker vibrating plate
703
made of plastic and having the corrugated periphery
703
a
and the central dome, the voice coil
704
secured to the underside of the vibrating plate
703
at a central portion, and the magnet composition
710
. The vibrating plate
703
is secured to the frame
709
with adhesives.
The magnetic composition
710
comprises a lower yoke
803
, core
701
formed on the yoke
803
at a central portion thereof, an annular permanent magnet
802
secured to the lower yoke
803
, and annular upper yoke
706
having a peripheral wall
706
b
and mounted on the permanent magnet
702
. The upper yoke
706
is resiliently supported in the frame
709
by spring plates
807
and
808
. A first magnetic gap
801
is formed between a periphery
701
a
of the core
701
and an inside wall
706
a
of the upper yoke
706
to be magnetically connected to the voice coil
704
. A second gap
805
is formed between a periphery
803
a
of the lower yoke
803
and inside wall
706
a
of the upper yoke
706
. A driving coil
806
is secured to the frame and inserted in the second gap
805
.
When an alternating voltage is applied to the voice coil
704
through input terminals
712
a
and
712
b
, the speaker vibrating plate
703
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
704
, the speaker vibrating plate
703
and the magnetic composition
710
are sequentially vibrated, since the magnetic composition
710
and the speaker vibrating plate
703
are relatively moved through the magnetic combination of the voice coil
704
and the magnet composition
710
.
When a high frequency signal for music is applied to the voice coil
704
, only the speaker vibrating plate
703
is vibrated. Therefore, there does not occur distortion of the sound. Furthermore, when a low frequency signal is applied to the driving coil
806
, only the magnetic composition
710
is vibrated, and the speaker vibrating plate
703
is not vibrated.
However if a high frequency signal is applied to input terminals
712
a
,
712
b
, and a low frequency signal is also applied to input terminals
804
a
,
804
b
, the speaker vibrating plate
703
and magnetic composition
710
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 vibrating plate supported in the frame, a voice coil secured to the speaker vibrating plate, a rotor having magnetic poles and rotatably supported in the frame, a stator having magnetic poles and provided in the frame, corresponding to the rotor, a first permanent magnet provided on the rotor, at least one coil for forming magnetic fluxes between the magnetic poles of the rotor and the magnetic poles of the stator.
The device further comprises

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