Electrical audio signal processing systems and devices – Electro-acoustic audio transducer – Electromagnetic
Reexamination Certificate
2001-01-05
2003-07-08
Le, Huyen (Department: 2643)
Electrical audio signal processing systems and devices
Electro-acoustic audio transducer
Electromagnetic
C381S396000, C381S410000
Reexamination Certificate
active
06590991
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to sound-vibration generating devices to be incorporated into portable communications devices such as portable telephones and pagers, or small devices such as wristwatches and toys.
2. Description of the Related Art
Conventional portable telephones have incorporated therein a sound generator (ringer) for notifying the user of incoming calls with sound, and a vibration generator for notifying the user of incoming calls by vibrating the body of the telephone. One of the two generators is selectively usable according to the situation.
However, a sufficient space is not available in small devices such as portable telephones for accommodating both the sound generator and the vibration generator, and the provision of these two generators entails the problem of making the device larger.
Accordingly, the present inventor has proposed a compact sound-vibration generating device having the functions of both the sound generator and the vibration generator as shown in
FIGS. 13 and 14
(JP-A No. 14194/1998).
The sound-vibration generating device includes two vibration systems housed in a resin casing
110
. The casing
110
includes a lower case
110
a
for supporting a first vibration system, and an upper case
110
b
for supporting a second vibration system. The upper case
110
b
has a sound release aperture
111
formed in its central portion.
The first vibration system includes a first diaphragm
112
having a plurality of swirling slits, and a first vibrator
116
having a permanent magnet
113
. The first vibrator
116
is attached by adhesion to the inner peripheral portion of the first diaphragm
112
, the outer peripheral portion of which is attached to the lower case
110
a
by adhesion. The first vibration system can therefore be vibrated up and down relative to the lower case
110
a
. The first vibrator
116
includes an upper yoke
114
and a lower yoke
115
which are arranged respectively on the upper and lower sides of the permanent magnet
113
, whereby a magnetic circuit is provided. The magnet
113
is magnetized such that the upper side thereof provides an N pole, with the lower side thereof serving as an S pole. The upper yoke
114
is in the form of a ring having an inner periphery formed by a vertical wall, while the lower yoke
115
is in the form of a disk having a central protrusion. A magnetic gap
121
is formed between the vertical wall of the upper yoke
114
and the central protrusion of the lower yoke
115
for making a second vibrator
117
movable up and down.
On the other hand, the second vibration system includes a second diaphragm
122
, and the second vibrator
117
which has a coil
118
. The second diaphragm
122
has an inner peripheral portion having the second vibrator
117
attached thereto by adhesion and an outer peripheral portion attached to the upper case
110
b
by adhesion, whereby the second vibration system is made vibratable vertically relative to the upper case
110
b
. The coil
118
of the second vibrator
117
is supported by a hollow cylindrical bobbin
119
on the rear side of the second diaphragm
122
. The coil
118
and the bobbin
119
are arranged such as to be movable in the magnetic gap
121
of the first vibrator
116
.
The second vibration system has a natural frequency (for example, of about 2 kHz) in the audible range, while the first vibration system has a lower natural frequency (for example, of about 100 Hz) than the second vibration system. Accordingly, the second vibration system can be resonated to produce sound by connecting a drive circuit (not shown) to a pair of free ends
123
,
123
of the coil
118
and feeding to the coil
118
a drive signal having the natural frequency of the second vibration system. On the other hand, the first vibration system can be resonated to produce a vibration perceivable by the human body by feeding to the coil
118
a drive signal having the natural frequency of the first vibration system.
A study is under way on a method of mounting the sound-vibration generating device on a printed wiring board by inserting a pair of terminal pins through an end portion of the casing
110
axially of the casing, attaching the pins to the end portion, connecting the pair of free ends of the coil
118
to the upper ends of the respective terminal pins, inserting the lower ends of the terminal pins through holes in the wiring board to position the sound-vibration generating device in place, and soldering the pin lower ends to the rear surface of the wiring board for electrical connection, i.e., a mounting method by dipping.
However, the mounting method by dipping permits the lower ends of the terminal pins and the solder joints to project from the rear surface of the printed wiring board, resulting in an increased thickness for the assembly of printed wiring board and an increased size for the device, such as a portable telephone, in which the generating device is to be incorporated.
Moreover, dipping involves the necessity of performing the step of solder reflow separately from the assembly step of installing the sound-vibration generating device on the printed wiring board, resulting in an increased manufacturing cost.
Accordingly, a first object of the present invention is to provide a sound-vibration generating device which is adapted for surface mounting to thereby overcome all the foregoing problems.
In the case where the conventional sound-vibration generating device is to be incorporated into small devices such as portable telephones, there is a need to fix the rear surface of the casing
110
to the surface of a printed wiring board or the like, whereas because the first vibration system is especially great in mass of vibration to produce a great vibrating force through resonance, sufficient rigidity is required of the casing
110
, especially of the lower case
110
a
serving as the support portion. Furthermore, the adhesive joint between the outer peripheral portion of the first diaphragm
112
and the lower case
110
a
which is subjected directly to the force of vibration requires a sufficient adhesion strength to receive the force of vibration.
The conventional sound-vibration generating device nevertheless suffers from the problem that an effective construction is not always utilized for providing sufficient rigidity to the lower case
110
a
and imparting a satisfactory adhesion strength to the adhesive joint between the outer peripheral portion of the first diaphragm
112
and the lower case
110
a.
Accordingly, a second object of the present invention is to provide a sound-vibration generating device the body of which is supportable with sufficient rigidity and which has satisfactory strength against vibrating force produced by vibration.
The diaphragm
112
of the first vibration system has a spring structure provided with a plurality of swirling slits to produce a great amplitude, so that when subjected to an impact, for example, after falling, the first vibration system becomes excessively displaced, not only permitting the excessive displacement to cause damage to the diaphragm itself but also allowing the upper yoke
114
or lower yoke
115
to come into direct contact with the diaphragm
122
of the second vibration system to possibly cause damage also to the second diaphragm
122
. Because the diaphragms
112
,
122
are relatively low in strength, there arises the problem that the sound-vibration generating device fails to operate normally.
Accordingly, a third object of the present invention is to provide a sound-vibration generating device in which the diaphragm or like component is unlikely to be damaged even if subjected to an impact.
SUMMARY OF THE INVENTION
The present invention provides a first sound-vibration generating device which includes as arranged in a main body case
10
a sound generating unit
9
for producing sound toward the outside of the main body case
10
, and a vibration generating unit
6
for vibrating the main body case
10
.
The main body case
10
has att
Armstrong Westerman & Hattori, LLP
Le Huyen
Sanyo Electric Co,. Ltd.
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