Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Reexamination Certificate
1998-11-18
2001-01-16
Gaffin, Jeffrey (Department: 2841)
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
C029S840000, C029S843000
Reexamination Certificate
active
06175086
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method for installing terminals on a circuit board comprising desired electronic circuits and electrical circuits, and to a circuit board used in this method.
BACKGROUND ART
FIG. 18
shows one example of a conventional structure wherein terminals are installed on a circuit board. In the structure illustrated in this diagram, terminal
9
has a thin plate shape and is made from metal, and it comprises a connecting end
9
a
and a non-connecting end
9
b
. The connecting end
9
a
is soldered to the circuit board
1
E, whilst the non-connecting end
9
b
projects externally from the circuit board
1
E. By adopting a composition of this kind, it is possible to bend the aforementioned non-connecting end, if necessary, as indicated by the imaginary line in the diagram, and this is convenient for making the non-connecting end
9
b
into the electrode of a cell, or the terminal of a further circuit board, or the like.
Since the task of soldering the aforementioned terminal
9
to the circuit board is carried out manually by an operator, the work efficiency is poor. Therefore, conventionally, reflow soldering has been adopted as a method for soldering the aforementioned terminal
9
. This reflow soldering method comprises a step of coating solder paste onto the surface of the circuit board
1
E, a step of superimposing the aforementioned connecting end
9
a
over the region of the board coated with the solder paste, and a step of heating and melting the aforementioned solder paste, and this sequence of steps can be automated.
However, in the prior art, the following problems occur when the connecting end
9
a
is soldered to the circuit board
1
E by means of a reflow soldering method.
Namely, as shown in
FIG. 19
for example, in a case where the two end regions
9
c
,
9
d
of a terminal
9
A of a set length are superimposed on two regions
35
,
35
coated with solder paste, a self-alignment effect is obtained. This is due to the fact that when the solder paste in the aforementioned two regions
35
,
35
coated with solder paste are heated and melted, the surface tension of the molten solder acts respectively on each end region
9
c
,
9
d
, and a force aligning the whole of the terminal
9
A with the aforementioned two solder paste coated regions
35
,
35
is exhibited. In order to obtain a self-alignment effect in this way by using a reflow soldering method, it is necessary for the surface tension of the molten solder to act on the terminal at a plurality of points.
However, in the structure illustrated in
FIG. 18
, only connecting end
9
a
of the aforementioned terminal
9
is soldered to the circuit board
1
E, and therefore the surface tension of the molten solder only acts on this portion of the terminal. Therefore, in the prior art, in a case where the aforementioned terminal
9
is installed on the circuit board
1
E, a problem arises in that no self-alignment effect is obtained and therefore positional accuracy of the terminal
9
declines.
Conventionally, as means for raising the positional accuracy of the terminal
9
, pins for registering the location of the terminal
9
may be provided on the circuit board
1
E. However, in the case of means of this kind, the aforementioned pins present an obstacle when installing the terminal
9
on the aforementioned circuit board
1
E, and there have been instances where automatic installation of the terminal
9
by means of an automatic mounting device has been difficult to implement. Moreover, problems have also arisen in that the task of providing the aforementioned pins on the circuit board
1
E in advance is complicated.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a method for installing terminals on a circuit board, whereby the aforementioned problems can be resolved or alleviated. Moreover, it is a further object of the present invention to provide a circuit board on which the aforementioned method can be implemented appropriately.
A first aspect of the present invention is a method for installing terminals on a circuit board comprising a coating step for coating solder paste onto a desired circuit board, a superimposing step for superimposing the connecting end of a terminal comprising a connecting end and a non-connecting end onto a region where the solder paste is coated, and a step for heating and melting the solder paste in order to solder the connecting end to the circuit board, characterized in that, in the coating step, a plurality of mutually separated solder paste coated regions are provided on the circuit board; and in the superimposing step, the connecting end is superimposed such that it extends over the plurality of solder paste coated regions.
A second aspect of the present invention is a circuit board whereon solder paste is coated for soldering the connecting end of a terminal comprising a connecting end and a non-connecting end, characterized in that a plurality of mutually separated solder paste coated regions are provided by coating the solder paste onto a plurality of regions separately, and the plurality of solder paste coated regions are located in mutually proximate positions whereby the connecting end can be superimposed such that it extends over the solder paste coated regions.
Desirably, the solder paste coated regions are provided in at least three or more positions, each of these solder paste coated regions being mutually separated by an interval in both the longitudinal direction and the lateral direction of the aforementioned terminal.
Desirably, a pad region having an approximate square shape in plan view for providing an electrical connection with the terminal is provided on the circuit board, and the plurality of solder paste coated regions are provided in the four corner regions of the pad region.
Desirably, a further solder paste coated region separated from the aforementioned plurality of solder paste coated regions is provided in approximately the central portion of the pad region.
Desirably, the plurality of solder paste coated regions is provided by forming a plurality of mutually separated metal surface regions and coating the solder paste in a distributed manner onto the respective surfaces of this plurality of metal surface regions.
A third aspect of the present invention is a method for installing terminals on a circuit board comprising a coating step for coating solder paste onto a desired circuit board, a superimposing step for superimposing the connecting end of a terminal comprising a connecting end and a non-connecting end onto a region where the solder paste is coated, and a step for heating and melting the solder paste in order to solder the connecting end to the circuit board, characterized in that, in the coating step, a solder paste coated region comprising a plurality of protruding regions at the outer perimeter thereof is provided on the circuit board; and in the superimposing step, the connecting end is superimposed on the solder paste coated region such that the plurality of protruding regions extend beyond the connecting end.
A fourth aspect of the present invention is a circuit board whereon solder paste is coated for soldering the connecting end of a terminal comprising a connecting end and a non-connecting end, characterized in that the solder paste is coated in a shape comprising a plurality of protruding regions which are capable of projecting beyond the connecting end when the connecting end is superimposed on the solder paste coated region.
Desirably, the connecting end comprises a first edge extending in the lateral direction of the terminal and two second edges extending in the longitudinal direction of the terminal and connecting with the first edge, and the plurality of protruding regions are provided in at least three or more locations, in such a manner that they project beyond the first edge and the two second edges, respectively.
The various characteristics and advantages of the present invention shall become apparent by means of the embodiments described hereinaf
Gaffin Jeffrey
Merchant & Gould P.C.
Norris Jeremy
Rohm & Co., Ltd.
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