Acoustics – Diaphragm – With direct mechanical connection to drive unit
Reexamination Certificate
2001-06-01
2003-06-17
Hsieh, Shih-yung (Department: 2837)
Acoustics
Diaphragm
With direct mechanical connection to drive unit
C181S157000, C181S163000, C181S164000, C181S165000, C181S171000
Reexamination Certificate
active
06578661
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a speaker apparatus for use with various acoustic devices, visual devices and the like, for example.
2. Description of the Related Art
FIG. 1
shows an example of a speaker apparatus according to the related art. As shown in
FIG. 1
, this related-art speaker apparatus includes a dome-like acoustic diaphragm
121
at its center. A diaphragm having a curvature R in cross-section or a straight-line-like edge is formed from the side edge of this acoustic diaphragm
121
.
A plate
126
is provided on a magnet
124
and a voice coil
123
is formed so as to have a gap
127
between it and a pole piece
125
. Then, a bobbin
122
of the voice coil
123
is fixed to the acoustic diaphragm
121
.
Accordingly, when a signal is inputted to a signal input line
128
, the voice coil
123
is vibrated in the upper and lower direction by electromagnetic force applied to a current flowing through the voice coil
123
in a magnetic field generated by the magnet
124
. Concurrently therewith, the acoustic diaphragm
121
is actuated to produce audio-frequency vibrations.
FIG. 1
shows a conductive type speaker as an example of the related-art speaker apparatus.
In the case of the conductive type speaker, for example, in order to drive this diaphragm, as shown in
FIG. 2
which illustrates a method of bonding a conductive type speaker diaphragm and a voice coil bobbin, a voice coil
138
is wound around a cylindrical bobbin
137
having a uniform diameter, and a front end of the bobbin
137
is bonded to a dome-like inner peripheral edge portion
133
of a dome-like diaphragm
132
of a diaphragm
131
by an adhesive agent
139
.
This diaphragm
131
is fixed to a suitable means such as a frame, not shown, from a side edge of the dome-like diaphragm
132
through a joint flat portion
134
by a diaphragm side edge
136
of an edge-like diaphragm
135
having a curved-line-like cross-section or a straight-line-like cross-section.
On the other hand, in the case of a conductive type electromagnetic induction speaker, as shown in
FIG. 3
which illustrates a method of bonding a conductive type electromagnetic induction speaker diaphragm and a voice coil bobbin, a conductive one turn ring
148
is fixed around a cylindrical bobbin
147
having a uniform diameter, and a front end of the bobbin
147
is bonded to a dome-like diaphragm inner peripheral edge portion
143
of a dome-like diaphragm
142
of a diaphragm
141
by an adhesive agent
149
.
Alternatively, as shown in
FIG. 4
which illustrates a method of bonding a conductive type electromagnetic induction speaker diaphragm and a conductive one turn ring, a front end of a cylindrical conductive one turn ring
157
having a uniform diameter is bonded to a dome-like diaphragm inner peripheral edge portion
153
of a dome-like diaphragm
152
of a diaphragm
151
by an adhesive agent
158
.
As shown in
FIG. 1
, the conductive type speaker and the conductive type electromagnetic induction speaker are each comprised of a magnetic circuit including a permanent magnet (magnet
124
) and the magnetic gap
127
. The voice coil
138
shown in
FIG. 2
or the conductive one turn rings
148
,
157
shown in
FIGS. 3 and 4
are held within this magnetic gap
127
.
Accordingly, as shown in
FIG. 2
, when a signal current flows through the voice coil
138
, the diaphragm
131
is vibrated to output acoustic energies.
Alternatively, as shown in
FIGS. 3 and 4
, when an induced current of a signal current flows through the conductive one turn rings
148
,
157
, the diaphragms
141
,
151
are vibrated to output acoustic energies.
However, in the above related-art speaker apparatus, the diaphragms
131
,
141
,
151
including the dome-like diaphragms
132
,
142
,
152
and the edge-like diaphragms
135
,
145
,
155
are each manufactured by integrally molding a thin metal sheet such as an aluminum sheet and a titanium sheet or a polymer sheet, and the like. As a result, since the metal sheet or the polymer sheet and the like is pulled in both directions, it is unavoidable that the joint flat portions
134
,
144
,
154
for joining the dome-like diaphragms
132
,
142
,
152
and the edge-like diaphragms
135
,
145
,
155
are reduced in thickness.
When the voice bobbins
137
,
147
or the conductive one turn ring
157
are bonded to the diaphragms
131
,
141
,
151
by the above related-art bonding methods and an acoustic signal is inputted to the speaker apparatus, at a certain frequency, the dome portions and the edge portions are vibrated to produce audio-frequency vibrations whose phases are displaced by 180 degrees across the joint flat portions
134
,
144
,
154
having a small mechanical strength. At this frequency, the acoustic signal generated from the dome portion and the acoustic signal generated from the edge portion are canceled with each other out so that a dip of a sound pressure occurs. In particular, when this dip of the sound pressure lies in an audible band, a quality of an acoustic signal is degraded.
SUMMARY OF THE INVENTION
In view of the aforesaid aspect, it is an object of the present invention to provide a speaker apparatus capable of eliminating vibrations of the dome portion and the edge portion with a phase difference of 180 degrees and which is capable of reproducing sounds of excellent quality of acoustic signals having high audio frequencies by increasing a strength of a flat joint portion and by properly setting a mass ratio between a dome-like diaphragm and an edge-like diaphragm of a speaker diaphragm.
According to an aspect of the present invention, there is provided a conductive type speaker apparatus in which a speaker diaphragm formed by joining a dome-like diaphragm and an edge-like diaphragm is actuated to vibrate by using a voice coil. This speaker apparatus is comprised of a diaphragm portion in which a mass ratio of the edge-like diaphragm relative to the dome-like diaphragm falls within a predetermined range near 1 and a fixed portion at which an end face of the voice coil bobbin is bonded to and fixed to a flat portion for joining the dome-like diaphragm and the edge-like diaphragm.
According to another aspect of the present invention, there is provided a conductive electromagnetic induction speaker in which a speaker diaphragm formed by joining a dome-like diaphragm and an edge-like diaphragm is vibrated by electromagnetic induction generated from a conductive one turn ring. This conductive electromagnetic induction speaker is comprised of a diaphragm portion in which a mass ratio of the edge-like diaphragm relative to the dome-like diaphragm falls within a predetermined range near 1 and a fixed portion at which an end face of the conductive one turn ring is bonded to and fixed to a flat portion for joining the dome-like diaphragm and the edge-like diaphragm.
In the speaker apparatus according to the present invention, a diaphragm of a conductive type speaker and a conductive type electromagnetic induction speaker is molded in such a manner that a mass ratio between the central dome-like diaphragm and the edge-like diaphragm falls within a range near 1, e.g., a mass ratio falls within a range of from 0.5 to 1.5. Further, since the end face of the voice coil bobbin or the end face of the conductive one turn ring is bonded to the flat portion which joints the central dome-like diaphragm and the edge-like diaphragm, a mechanical strength of the flat portion can be increased.
Therefore, according to the present invention, there can be obtained the following actions.
According to the speaker apparatus including the diaphragm portion comprised of the dome-like diaphragm and the edge-like diaphragm and the fixed portion bonded to and fixed to the coil bobbin or the conductive one turn ring and the flat portion, by increasing strength of the joint flat portions joining the dome-like diaphragm and the edge-like diaphragm the mechanical strength of which has been weak, vibrations of the dome-like diaphragm and the edge-like diap
Ohashi Yoshio
Uryu Masaru
Hsieh Shih-yung
Maioli Jay H.
Sony Corporation
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