Inductor devices – With vibration control
Reexamination Certificate
2000-10-27
2002-08-20
Sircus, Brian (Department: 2839)
Inductor devices
With vibration control
C439S038000
Reexamination Certificate
active
06437675
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a linear coil; in particular, the invention relates to a linear coil having the capability of inhibiting acoustic noises.
2. Description of the Related Art
A linear coil is usually installed in a display, for example, a CRT monitor or a television in which the linear coil is installed for a linear correction of such display. For instance, when the linear coil is installed on the printed circuit board of the display, the picture of the display can be linearly corrected by means of a deflection current of the linear coil. A typical structure of the conventional linear coil is described as follows with reference to the layout structure of the printed circuit board.
FIG. 1
shows a display
10
, which is mainly consisted of a printed circuit board
11
and a deflection yoke
12
. In addition, a flyback transformer
13
, a horizontal width adjustment coil
14
, and a linear coil
15
are also installed on the printed circuit board
11
.
The structure of a conventional linear coil
20
is shown in
FIG. 2
, wherein the linear coil
20
comprises a compensation part
21
, a linearity part
22
, a magnetic portion
23
, a base
24
, and a plurality of connectors
25
. The base
24
, made of hard rubber, is used for supporting the compensation part
21
, the linearity part
22
, and the magnetic portion
23
. The linear coil
20
may be fixedly disposed on the printed circuit board
11
by means of the connectors
25
. The connectors
25
, made of metal of high rigidity, include a first connector
251
, a second connector
252
, a third connector
253
, and a fourth connector
254
. Thereby, the base
24
may be fixedly disposed on the printed circuit board so as to electrically connect the linear coil
20
to the printed circuit board of the display. In addition, the magnetic portion
23
is a permanent magnet. The adhesion among the compensation part
21
, the linearity part
22
, the magnetic portion
23
, and the base
24
for putting together a complete linear coil
20
is by means of an adhesive such as epoxy.
The linearity part
22
comprises a linearity core
221
and a first wire
222
. For example, the linearity core
221
is made of ferrite, and the first wire
222
surrounds the linearity core
221
. In addition, one end of the first wire
222
leads to the first connector
251
, and the other end of the first wire
222
leads to the second connector
252
.
The compensation part
21
comprises a compensation core
211
and a second wire
212
. For example, the compensation core
211
is made of ferrite, and the second wire
212
surrounds the compensation core
211
. In addition, one end of the second wire
212
leads to the third connector
253
, and the other end of the second wire
212
leads to the fourth connector
254
.
The structure of the conventional linear coil
20
is therefore described as above. On the other hand, the operating principle of the conventional linear coil
20
is described as follows.
The current from the printed circuit board flows to the first wire
222
of the conventional linear coil
20
via a connector, for example, the first connector
251
. While the current flows in the first wire
222
, it flows around the linear core
221
. Then, the current flows back to the printed circuit board via another connector, for example, the second connector
252
. Furthermore, as the deflection current flows around the linearity core
221
, the resistance of the linearity part
22
, that acts against the deflection current, linearly corrects the picture of the display
10
in order to attain a fine picture.
The compensation part
21
is used for spreading the operation range, and the operating principle of the compensation part
21
is similar to that of the linearity part
22
. The current from the printed circuit board flows to the second wire
212
of the conventional linear coil
20
via a connector, for example, the third connector
253
. While the current flows in the second wire
212
, it flows around the compensation core
211
. Then, the current flows back to the printed circuit board via another connector, for example, the fourth connector
254
. Furthermore, as the deflection current flows around the compensation core
211
, the compensation part
21
generates a magnetic field to influence the magnetic field generated by the linearity part
22
. As a result, the characteristic curve of the linearity part
22
is shifted and the linear correcting range of the linearity part
22
is changed.
Furthermore, the magnetic portion
23
is a permanent magnet, wherein the function of the magnetic portion
23
is to shift the characteristic curve of the linearity part
22
to a linear zone.
The operating theorem of the conventional linear coil
20
is described as above. However, as the alternating current with high frequency flows around the linearity core
221
, the linearity core
221
generates a magnetic force. Because the magnitude and direction of the alternative current keeps changing, the attraction force and the rejection force are repeatedly and periodically generated between the linearity part
22
and the magnetic portion
23
. Such an attraction force or a rejection force may cause a collision between the linearity core
221
and the magnetic portion
23
, which may eventually transfer this collision to the printed circuit board via the base
24
and the connectors
25
. As a result, vibration in the printed circuit board can be generated accompanied with a high frequency acoustic noise. In addition, collision may also occur between the compensation part
21
and the linearity part
22
, which is however not so obvious comparing with the collision between the linearity core
221
and the magnetic portion
23
.
Referring to FIG.
3
and
FIG. 4
, a notch
2211
is provided atop the linearity core
221
of the conventional linear coil to accommodate the first wire
222
. Nevertheless, such a conventional design makes the first wire
222
contact a sharp edge of the magnetic portion
23
near the top directly, as shown in FIG.
4
. When the above-mentioned attraction force or rejection force are generated, a friction force is also generated between the first wire
222
and the sharp edge of the magnetic portion
23
, which at the same time induces an undesirable acoustic noise.
Furthermore, the structure of another conventional linear coil
40
is as shown in
FIG. 5
, wherein a compensation core
411
, a linearity core
421
, and a magnetic portion
43
of the conventional linear coil
40
are assembled together following the same manner as the compensation core
211
, the linearity core
221
, and the magnetic portion
23
of the linear coil
20
described above; hence, the description is herein omitted for briefness. However, the differences between the linear coil
40
and the linear coil
20
are described as follows. First of all, the connectors
441
,
442
of a base
44
of the linear coil
40
are used for simply fixing the base
44
to a printed circuit board. Secondly, two ends of a first wire
422
and two ends of a second wire
412
are electrically connected to the printed circuit board without being bound to the connectors as in the case of the linear coil
20
.
However, as in the case of the linear coil
20
, collision can still occur between the linearity core
421
and the magnetic portion
43
, which generates a high frequency acoustic noise.
SUMMARY OF THE INVENTION
In view of the disadvantages of the conventional linear coil, the present invention provides a linear coil capable of reducing acoustic noises related thereto.
According to the present invention, a linear coil comprising a base, a spacer, a magnetic portion, and a linearity part is installed on a printed circuit board. The base is fixedly installed on the printed circuit board in such manner that the spacer is disposed on the base, that the magnetic portion is disposed on the spacer, and that the linearity part is disposed on the magnetic portion. Accordingly, the spacer preven
Acer Communications and Multimedia Inc.
Ladas & Parry
Prasad Chandrika
Sircus Brian
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