Chip capacitor

Details Chip capacitor Chip capacitor

2000-06-15

2001-07-17

Reichard, Dean A. (Department: 2831)

Electricity: electrical systems and devices

Electrolytic systems or devices

Liquid electrolytic capacitor

C361S523000, C361S528000

Reexamination Certificate

active

06262878

ABSTRACT:

This invention relates to a small chip capacitor mounted on, for example, a printed circuit board.
BACKGROUND OF THE INVENTION
An example of prior art chip capacitors is shown in FIG.
1
. The chip capacitor shown in
FIG. 1
includes a solid-state tantalum capacitor element
2
with a cathode layer
4
disposed on its outer surface. An anode lead
6
is led out from one end surface of the capacitor element
2
. A flat cathode terminal
8
is connected to the cathode layer
4
with an electrically conductive adhesive (not shown). Also, a flat anode terminal
10
is welded to the tip end of the anode lead
6
. An encapsulation
12
is provided by transfer molding with epoxy resin. Outer end portions of the flat anode and cathode terminals
10
and
8
are bent to extend along the end surfaces of the encapsulation
12
and, then, further bent to extend along the bottom surface of the encapsulation
12
.
It is seen that a large proportion of the cathode terminal
8
is within the encapsulation
12
, and the proportion of the volume occupied by the cathode terminal
8
to the entire volume of the encapsulation
12
is large. Further, both the cathode terminal
8
and the anode terminal
10
include portions extending on the side surfaces of the encapsulation
12
. Accordingly, the length of the capacitor is increased by the thickness of these portions. In mounting such chip capacitor on a printed circuit board, the side surfaces of the cathode and anode terminals
8
and
10
are connected to the board by solder
14
. Accordingly, when a number of such chip capacitors are to be mounted on a board side by side, as shown in
FIG. 2
, the spacing between adjacent chip capacitors must be large enough to prevent short-circuiting of adjacent capacitors, which prevents dense packing of the capacitors. Recently, smallsized, portable electric and electronic devices, such as cellular phones, have been remarkably improved, and chip capacitors to be used in such devices are required to be down-sized. For down-sizing prior art chip capacitors like the ones described above, the volume occupied by the capacitor element
2
in the chip capacitor including the encapsulation
12
should be as small as possible, which sometimes prevents the chip capacitor from having desired capacitance.
Therefore an object of the present invention is to provide a chip capacitor which makes high density packing possible, and can have desired capacitance, while being small in size.
SUMMARY OF THE INVENTION
A chip capacitor according to the present invention includes a capacitor element, which has a cathode layer formed on its outer surface. The cathode layer has at least one surface thereof flattened. An anode lead extends from one end of the capacitor element. The anode lead may be pillar-shaped, e.g. cylinder-shaped or prism-shaped, or may be flat, e.g. plate-shaped or foil-shaped.
A flat cathode terminal is electrically connected to the cathode layer. The cathode terminal has first and second opposite major surfaces. The first major surface of the flat cathode terminal is located in a plane below and in parallel with the flat surface of the cathode layer. The first major surface of the cathode terminal is electrically connected to the flat surface of the cathode layer on the capacitor element.
A flat anode terminal having first and second opposite major surfaces is connected to the anode lead of the capacitor element. The first major surface of the anode terminal lies in substantially the same plane as the first major surface of the cathode terminal. The second major surface of the anode terminal is electrically connected to the anode lead of the capacitor element. The capacitor elements with the cathode layer and the anode lead, and the cathode and anode terminals are coated with or encapsulated in, for example, a plastic resin with at least portions of the second major surfaces of the cathode and anode terminals left exposed.
The exposed portions of the second surfaces of the cathode and anode terminals may be provided with regions set back toward their respective first surfaces.
The outer edge of the cathode terminal may be located in the vicinity of the end of the capacitor element opposite to the one end from which the anode lead extends.
The anode terminal may have its outer edge located in the vicinity of the tip end of the anode lead, and have its inner edge located beneath the flat surface of the cathode layer, being insulated therefrom.
The anode terminal may have a raised portion which can contact with the anode lead. The raised portion and the anode lead are electrically connected with each other.
The anode lead may extend out from the capacitor element at a location near the flat surface of the cathode layer so as to enable direct connection of the anode lead to the anode terminal.
The anode lead may be electrically connected to the anode terminal by a connector. The connector has an anode-lead contacting portion contacting the upper portion of the anode lead, legs extending from opposite ends of the anode-lead contacting portion toward the anode terminal, and feet disposed at the distal ends of the legs to contact the anode terminal, when the connector is positioned in place. The anode lead and the anode-lead contacting portion are electrically connected with each other, and the feet are electrically connected to the anode terminal.


REFERENCES:
patent: 4539623 (1985-09-01), Irikura et al.
patent: 5390074 (1995-02-01), Hasegawa et al.
patent: 5629830 (1997-05-01), Yamagami et al.
patent: 5926363 (1999-07-01), Kuriyama
patent: 55-47449 B2 (1980-11-01), None
patent: 1-29050 B2 (1989-06-01), None

Affiliated with

Also associated with

Rating

Chip capacitor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Chip capacitor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chip capacitor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2437683