Electrical audio signal processing systems and devices – Electro-acoustic audio transducer – Electromagnetic
Reexamination Certificate
2001-04-10
2003-06-10
Le, Huyen (Department: 2643)
Electrical audio signal processing systems and devices
Electro-acoustic audio transducer
Electromagnetic
C381S410000, C381S417000, C439S065000
Reexamination Certificate
active
06577743
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electroacoustic transducer such as a sounder (buzzer), a microphone, or a loudspeaker, and more particularly to an improvement in which, in the case where an electroacoustic transducer is to be mounted on a board of one of various devices including a portable telephone, directionality in a circumferential direction (rotation direction) can be eliminated without using a sheet or a connector that may be separately prepared, thereby facilitating the mounting work.
2. Description of the Related Art
A sounder which is an electroacoustic transducer has a configuration such as shown in FIG.
21
. The sounder has a case
301
which is configured by a top plate
303
and a cylindrical portion
305
. Alternatively, the case
301
of the sounder may have a rectangular shape as shown in
FIG. 23. A
sound release hole
307
is formed in the center position of the top plate
303
. A base
309
is placed in a lower portion of the inner space of the case
301
, and a board
311
is placed on the side of the lower face of the base
309
. A core
313
is attached to the center positions of the base
309
and the board
311
. The base
309
and the core
313
constitute so-called “pole piece”.
A coil
315
is placed on the base
309
and wound around the outer periphery of the core
313
. A magnet
317
is interposed between the outer periphery of the coil
315
and the cylindrical portion
305
of the case
301
, with forming a gap between the magnet and the coil
315
.
A stepped portion
319
is formed in an inner peripheral side of an upper end portion of the cylindrical portion
305
of the case
301
. A diaphragm
321
is placed on the stepped portion
319
. The diaphragm
321
is configured by an elastic plate
323
, and a magnetic piece
325
which serves as an additional mass fixed to the center position of the elastic plate
323
.
The ends of the coil
315
are passed through the base
309
and the board
311
, and then connected to a pair of lead terminals (not shown) which are disposed on the lower face of the board
311
.
The thus configured sounder operates in the following manner. The diaphragm
321
is ordinarily attracted to the magnet
317
to have a certain polarity. When a current is supplied to the coil
315
via the pair of lead terminals under this state, the core
313
is electromagnetized. As a result, a magnetic field is generated at the forward end of the core. At this time, in the case where the magnetic pole which is generated at the core
313
is different in polarity from that of the diaphragm
321
, the diaphragm
321
is attracted to the core
313
.
By contrast, when the magnetic pole of the core
313
is identical in polarity with that of the diaphragm
321
, the diaphragm
321
is repelled from the core
313
. When a current is intermittently supplied in a certain direction, therefore, the diaphragm
321
repeatedly conducts the above-mentioned operations, with the result that the diaphragm
321
is oscillated at a predetermined frequency to generate a sound.
The sounder configured as described above is mounted on a board
327
in a housing of, for example, a portable telephone. In the mounting of the sounder to the board
327
, a sheet
329
is attached to the sounder to eliminate directionality in a circumferential direction. Specifically, as shown in
FIG. 22
, an anode conductive part
329
a
and a cathode conductive part
329
b
are disposed on the lower face of the sheet
329
in ring-like shapes which are concentric with each other.
A large number of conductive pins are formed on the sheet
329
. The anode conductive part
329
a
and the cathode conductive part
329
b
are made conductive with the board
311
through the conductive pins.
When the sheet
329
is attached to the sounder, the sounder has no directionality in a circumferential direction with respect to an anode conductive part and a cathode conductive part of the board
327
of the portable telephone. Even when the sounder is mounted on the board
327
with being rotated or positioned at any degree in a circumferential direction, therefore, conduction between the sounder and the board
327
can be surely attained.
The anode conductive part and the cathode conductive part of the board
327
are placed in given radial positions corresponding to the anode conductive part
329
a
and the cathode conductive part
329
b
of the sheet
329
.
In
FIG. 21
, the reference numeral
331
denotes a gasket serving as a cushion member. In the mounting of the sounder to the board
327
in the housing of the portable telephone, various electronic components including the sounder are clamped by the board
327
and the housing. Therefore, the gasket
331
is placed.
As a measure for eliminating directionality in mounting in a circumferential direction, it may be contemplated to dispose a predetermined connector on the board
327
of the portable telephone in place of attachment of the sheet
329
to the sounder.
The above-described configuration of the conventional art has the following problems.
A sounder of the conventional art is not configured so that directionality in mounting in a circumferential direction can be eliminated on the side of the sounder. Therefore, a measure such as that the sheet
329
which is separately prepared is attached, or that a connector is attached to the board
327
is required. This produces problems that extra components are necessary, and that a cumbersome work must be compulsively conducted.
Another problem is caused by the use of the sheet or the connector. A sounder is shipped with the acoustic performance previously adjusted. The acoustic performance may be changed by the sheet
329
or the connector which is thereafter attached to the sounder, thereby producing a problem that a sounder cannot provide desired acoustic performance.
Specifically, when the sheet
329
or the connector is disposed on the back face of the sounder, it is expected that the resonance space on the rear side of the diaphragm is closed or narrowed, whereby acoustic performance is changed. As a countermeasure against this, it may be contemplated that acoustic performance is adjusted and set previously in consideration of the sheet
329
or the connector. However, the sheet
329
or the connector is configured in various manners in accordance with requirements of the user. Therefore, it is practically impossible to previously specify the kind of the sheet
329
or the connector.
Such a problem is commonly applicable not only to a sounder but also to various kinds of electroacoustic transducers such as a microphone or a loudspeaker.
SUMMARY OF THE INVENTION
The invention has been conducted in view of these problems, and therefore an object of the invention is to provide an electroacoustic transducer and a structure for mounting an electroacoustic transducer on a board of an external device in which directionality in a circumferential direction in mounting can be eliminated without changing the acoustic performance.
To achieve the above object, according to a first aspect of the invention, there is provided an electroacoustic transducer to be mounted on a board of a device, comprising:
an anode conductive part which is in press contact with the board of the device; and
a cathode conductive part which is in press contact with the board of the device;
wherein said anode conductive part and said cathode conductive part are respectively placed at an axial center position or at predetermined positions in a radial direction to eliminate directionality in a circumferential direction.
According to a second aspect of the invention, in the electroacoustic transducer of the first aspect of the invention, said anode conductive part and said cathode conductive part are disposed in substantially ring-like shapes which are concentric with each other.
According to a third aspect of the invention, in the electroacoustic transducer of the first or second aspect of the invention, said anode conductive part and said cathode conductiv
Imahori Yoshio
Masuda Mitsuhiro
Tsukuda Yasunori
Le Huyen
Star Micronics Co. Ltd.
Sughrue & Mion, PLLC
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