Electricity: electrical systems and devices – Electrostatic capacitors – Fixed capacitor
Reexamination Certificate
2001-04-20
2002-08-13
Reichard, Dean A. (Department: 2831)
Electricity: electrical systems and devices
Electrostatic capacitors
Fixed capacitor
C361S310000, C361S306100, C361S306300, C361S321600, C156S235000
Reexamination Certificate
active
06433995
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process of forming an electrode for a chip-like electronic part and a holder for a chip-like electronic part, particularly to a process of forming an electrode comprising a conductive paste on an outer surface of a chip-like electronic part and a holder for a chip-like electronic part preferably used in carrying out the process.
2. Description of Related Art
FIG. 18
shows a perspective view of a chip-like electronic part
1
, particularly a three terminal capacitor. End electrodes
2
and
3
are formed on respective end portions of the chip-like electronic part
1
and central electrodes
4
are formed at the central portion thereof.
Although not illustrated, first and second groups of inner electrodes are arranged alternately inside the chip-like electronic part
1
with the inner electrodes of the first group extending to the end electrodes
2
and
3
and the inner electrodes of the second group extending to the central electrodes
4
. Accordingly, electrostatic capacitances formed between the inner electrodes of the first group and the inner electrodes of the second group can be taken out between the end electrode
2
or
3
and the central electrodes
4
. The chip-like electronic part
1
is used to, for example, remove noise on a signal line by coupling the end electrodes
2
and
3
to the signal line and grounding the central electrodes
4
.
As shown in
FIG. 18
, the central electrodes
4
extend across two opposing side faces of the chip-like electronic part
1
. Because of limitations associated with the process commonly used to make the chip-like electronic part
1
, the central electrodes
4
extend only partially on the other side faces of the chip-like electronic part. As a result, the central electrodes
4
do not extend entirely around the outer side surfaces of the chip-like electronic part
1
.
The process for applying the central electrodes
4
is best understood with reference to FIG.
19
. As shown herein, a groove
6
is provided in a paste base
5
which comprises an elastic body. The groove
6
is filled with a conductive paste
7
to form an elongated streak
8
of conductive paste
3
. The chip-like electronic part
1
is held by a holder
9
so that one face of the chip-like electronic part
1
faces the streak
8
of conductive paste.
As best seen in
FIG. 18
, the chip-like electronic part
1
is an elongated parallel-piped structure having a main axis extending from end electrode
2
to end electrode
3
. The central portion of the chip-like electronic part
1
is aligned with the streak
8
of conductive paste with the axis of the streak extending perpendicular to the central axis of the chip-like electronic part
1
. The chip-like electronic part
1
is brought into contact with the paste base
5
and pressed against the paste base
5
to deform it and cause the conductive paste
7
to be applied to the outer surface of the chip-like electronic part
1
as shown by an imaginary line in FIG.
19
. Although the conductive paste
7
extends across the entire side face of the chip-like electronic part
1
which faces the base
5
, it only extends partway up the adjacent side faces of the chip-like electronic part
1
.
The orientation of the chip-like electronic part
1
is then reversed so that its opposite face extends away from the holder and towards the paste base
5
and the process is repeated to place the conductive paste
7
on the opposite face (and particularly up the adjacent side faces) of the chip-like electronic part
1
. Thereafter, the so applied central electrodes
4
are cured.
Instead of placing the conductive paste
7
in a groove
6
provided in the elastic paste base
5
, the conductive paste may be applied (by printing or the like) on a flat face of a paste base
5
which can be either elastic or rigid. As another alternative, a reservoir of conductive paste located on one side of a slit plate can be extruded to the other side of the slit plate via the slit in the plate by applying pressure to the conductive paste.
The end electrodes
2
and
3
are formed by dipping the ends of the chip-like electronic part
1
into a tank of conductive paste.
As mentioned above, the central electrode
4
does not normally extend around the entire outer surface of the chip-like electronic part
1
. However, it is preferable that it does to reduce unnecessary inductance components where the central electrode is used as a ground electrode.
It is not impossible to form the central electrode to extend around the entire circumference of the chip-like electronic part
1
using the process shown in FIG.
19
. This result can be achieved by providing a sufficient amount of conductive paste to extend at least half way up the two side faces of the chip-like electronic part
1
, for example, by making the groove deeper or pressing the chip-like electronic part
1
more strongly against the paste base
5
. However, as shown in the sectional view of
FIG. 20
, overlap portions
12
are formed on flat end faces of the chip-like electronic part. These overlap portions
12
can hamper the mountability of the chip-like electronic part. Accordingly, it is preferable that a built-up portion, such as the overlap portion
12
, not be formed at the central portion of any of the side faces of the chip-like electronic part
1
.
This can be avoided by using a small enough amount of conductive paste that only one side of the chip-like electronic part receives the paste during any single application. However, this will necessitate four separate applications of the conductive paste which is not efficient.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a process of forming an electrode of a chip-like electronic part and a holder for a chip-like electronic part used in the process which can resolve the above described problem.
To this end, the process of the present invention forms an electrode on a chip-like electronic part of the type having a central axis, a polygonal cross section as viewed in a plane which is perpendicular to the central axis, a plurality of side surfaces extending in respective planes which are generally parallel to the central axis, and a pair of end surfaces extending generally parallel to the central axis, each adjacent pair of side surfaces meeting along a respective edge of the chip-like electronic part, the process comprising the steps of:
applying a first band of conductive material to at least one of the side surfaces; and
applying a second band of conductive material to the remaining side surface(s) in such a manner that the first and second bands meet at respective ones of the edges and together form a continuous band of conductive material extending around the outer periphery of the chip-type electronic part.
In the preferred embodiment, the first and second bands are applied to the side surfaces at an area that lies between the end surfaces, and more preferably in the middle, of the chip-like electronic part and do not extend to either end surface.
In the preferred embodiment, the chip-like electronic part has four side surfaces, the first band is applied to first and second contiguous side surfaces and the second band is applied to third and fourth contiguous side surfaces by bringing the side surfaces into contact with strips of conductive paste. The chip-like electronic part is first held in a holder with the first and second side surfaces extending outwardly from the holder and the first band is applied to the first and second side surfaces by moving a strip of conductive paste located on an elastic paste base into contact with the first and second side surfaces. Thereafter, the orientation of the chip-like electronic part is changed by either moving it within the same holder or moving it to a second holder to ensure that the third and fourth side surfaces extend outwardly from the holder. Once in this position, the second band is applied to the third and fourth side surfaces by moving a strip of conductive paste
Fukuda Makoto
Nakagawa Tadahiro
Ha Nguyen
Murata Manufacturing Co. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
Reichard Dean A.
LandOfFree
Apparatus for forming electrode of chip-like electronic part does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for forming electrode of chip-like electronic part, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for forming electrode of chip-like electronic part will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2921998