Inductor devices – Coil or coil turn supports or spacers – Printed circuit-type coil
Reexamination Certificate
2000-08-25
2002-06-11
Mai, Anh (Department: 2832)
Inductor devices
Coil or coil turn supports or spacers
Printed circuit-type coil
C336S223000, C336S232000, C029S602100
Reexamination Certificate
active
06404319
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a variable inductance element, and more particularly, to a variable inductance element for use in a mobile communication device such as a mobile telephone or other suitable mobile communication device.
2. Description of the Related Art
In recent years, the size of mobile communication devices such as portable telephones has been substantially decreased, and demands for reducing the size of electronic components for use in the devices has substantially increased. Further, as higher frequencies are used in mobile communication devices, the circuits of the devices become more complex, and moreover, electronic components to be mounted in the devices must have uniform characteristics and high precision.
However, even where each electronic component included in a circuit has parameters with uniform characteristics and high precision, deviations in the parameters of the respective mounted electronic components have an overall or combined effect, so that in some cases, a desired function can be performed. Hence, some of the parameters of the electronic components included in an electronic circuit are variable, if necessary. By finely adjusting the parameters of some of the electronic components, a desired function of the circuit can be performed.
As a conventional trimming method for electronic components of the type described above, a method of trimming a variable inductance component, for example, as shown in
FIG. 4
has been generally known. A variable inductance element
55
includes a trimming area
53
provided on the surface of an insulating substrate
50
, connected to external electrodes
51
and
52
, which is arranged to function as an inductor. The trimming area
53
is irradiated with a laser beam emitted from a laser trimming machine (not shown) while the beam is linearly moved. The trimming area
53
is partially removed corresponding to the movement track of the laser beam, so that a linear trimming groove
54
is produced. Accordingly, the area of the trimming area
53
is altered such that the inductance of the trimming area
53
is finely adjusted.
In the conventional variable inductance element
55
, if the area of the trimming area
53
is relatively small, the variable range of the inductance is decreased, so that the circuit cannot be finely adjusted. Therefore, the trimming area
53
must have a large area. On the other hand, when a high precision laser trimming machine is used, the groove width (trimming width) of the trimming groove
54
produced by trimming once is relatively thin. For this reason, when a wide trimming width is required, irradiation with a laser beam must be repeated while the irradiation position is moved in parallel. Hence, the time required to achieve the fine adjustment is substantially increased.
Accordingly, a variable inductance element
65
is shown in FIG.
5
. The variable inductance element
65
includes an inductor pattern
61
provided on the surface of an insulating substrate
50
and connected to external electrodes
51
and
52
. The inductor pattern
61
is a ladder-shaped electrode including a U-shaped frame portion
61
a
and a plurality of lateral bars
61
b
arranged to cross two arms of the U-shaped frame portion
61
a
to be trimmed for adjustment of the inductance. The variable inductance element
65
is mounted on a printed circuit board or other suitable substrate, and is irradiated with a laser beam from above the variable inductance element
65
, so that a trimming groove
54
is produced in the inductance element
65
and simultaneously cuts the lateral bars
61
b
of the inductor pattern
61
individually and sequentially. Accordingly, the inductance between the external electrodes
51
and
52
can be altered in a stepwise manner.
The inductance element
65
has improved cutting workability, since the lateral bars
61
b
are arranged at relatively wide equal intervals. However, the amount of change of the inductance, caused every time one lateral bar
61
b
is cut, is relatively large, since all of the lateral bars
61
b
have an equal length. For this reason, in the inductance element
65
, the inductance cannot be altered equally in a stepwise manner. That is, fine adjustment of the inductance is difficult.
To solve this problem, a variable inductance element
75
is shown in FIG.
6
. The variable inductance element
75
has an inductor pattern
71
including a U-shaped frame portion
71
a
and a plurality of lateral bars
71
b
extending across two arms of the U-shaped frame portion
71
a
. The lateral bars
71
b
are arranged at intervals that become narrower in a stepwise manner. Hence, the amount of change of the inductance, caused every time one lateral bar
71
b
is cut, remains substantially constant. However, in the inductance element
75
, the intervals of the lateral bars
71
b
become narrower as the number of cut lateral bars
71
b
is increased. This increases the possibility that the lateral bars
71
b
may be erroneously cut, thus the adjustment of the inductance is difficult.
SUMMARY OF THE INVENTION
To overcome the above-described problems, preferred embodiments of the present invention provide a variable inductance element having a high Q factor, and in which the inductance is finely adjusted efficiently and accurately.
According to preferred embodiments of the present invention, a variable inductance element is provided including (a) an insulating substrate; and (b) an inductor pattern provided on the surface of the insulating substrate, (c) the inductor pattern being a ladder-shaped electrode having a substantially V-shaped frame portion and a plurality of lateral bars extending across two arms of the substantially V-shaped frame portion and arranged to be trimmed for adjustment of the inductance, the plurality of lateral bars being arranged at substantially equal intervals.
With the above-described configuration, the lengths of the respective lateral bars are sequentially decreased as the distance between the two arms of the substantially V-shaped frame portion is gradually reduced. Accordingly, when the lateral bars are sequentially cut in the order of decreasing length, the inductance of the variable inductance element does not change rapidly.
Preferably, the two arms of the substantially V-shaped frame portion have an angle of approximately 45° relative to the lateral bars. Accordingly, magnetic fields generated in the respective arms are substantially perpendicular to each other, thereby eliminating mutual interference.
Other features, elements, characteristics and advantages of preferred embodiments of the present invention will become apparent from the following detailed description of preferred embodiments thereof with reference to the attached drawings.
REFERENCES:
patent: 4342011 (1982-07-01), Iwamoto et al.
patent: 5140497 (1992-08-01), Kato et al.
patent: 5359315 (1994-10-01), Inoue et al.
patent: 6194248 (2001-02-01), Amaya et al.
patent: 6329715 (2001-12-01), Hayashi
patent: 5-267061 (1993-10-01), None
patent: 6-81124 (1994-11-01), None
patent: 07022819 (1995-01-01), None
Iida Naoki
Kawaguchi Masahiko
Keating & Bennett LLP
Mai Anh
Murata Manufacturing Co. Ltd.
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