Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – With provision to conduct electricity from panel circuit to...
Reexamination Certificate
2001-03-30
2002-06-11
Nguyen, Khiem (Department: 2839)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
With provision to conduct electricity from panel circuit to...
Reexamination Certificate
active
06402527
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a structure for connecting terminals, in which lands on a wiring board are connected with lead terminals on other substrate through solder or the like.
Conventionally, as such structure for connecting terminals, a structure of Prior Art 1 shown in
FIG. 4
is known, for example.
In the structure of Prior Art 1, near-square-form rectangular lands
11
are arranged in a side-by-side manner on a wiring board by pitch of 0.5 mm. Rectangular lead terminals
21
on other substrate are superimposed on the lands
11
. Long edges (long sides)
23
,
24
of the lead terminals
21
are longer than respective long edge
13
,
14
of the lands
11
by 0.1 mm, while short edges (short sides)
22
of the lead terminals
21
are shorter than respective short edges
12
of the lands by 0.1 mm.
As shown in the
FIG. 4
, the long edges
23
,
24
of the lead terminals
21
outwardly distanced from the respective long edges
13
,
14
of the lands
11
by 0.05 mm when the lands
11
and the lead terminals
21
are exactly in a designed position with each other. If the lands
11
and the lead terminals
21
are bonded through solder or similar conductive adhesives by automatic thermo-compression bonding in use of heat tool, fillets
5
of the solder or the like are formed on fringe portions on the lands
11
that outwardly protrude from the long edges
23
,
24
of the lead terminals
21
.
The structure shown in the
FIG. 4
is disadvantageous because even a 0.05 mm rightward or leftward deviation of the position of the lands
11
with respect to the lead terminals
21
makes the fillet
5
on right-hand side or left-hand side invisible from upper side through the other substrate, which has the lead terminals
21
.
On the other hand,
FIG. 5
shows another example of the conventional structure for connecting terminals, as designated as Prior Art 2.
In the structure of Prior Art 2, lands
11
as well as lead terminals
21
, each of which is superimposed to respective one of the lands
11
, are in a form of isosceles trapezoid, with longer base edges
18
of the lands
11
being opposed to longer base edges
19
of the lead terminals
21
. As shown in the
FIG. 4
, legs or oblique edges of the each land
11
and respective lead terminal
21
are intersected with each other, while shorter base edge
28
of the each lead terminals
21
is placed within the respective land
11
when exactly placed as designed. The fillets
5
are formed along imposed-on-the-land portion of outline of the lead terminal
21
. In a designed position, the longer base edge
18
of the land
11
is outwardly distanced from the shorter base edge
28
of the lead terminal
21
by 0.05 mm, while the shorter base edge
19
of the land
11
is inwardly distanced by 0.05 mm from the shorter base edge
29
of the lead terminal
21
.
The structure shown in the
FIG. 5
is disadvantageous because the fillet
5
becomes difficult to be recognized when position of the lead terminal
21
, which is superimposed on respective land
11
, is deviated in a length-wise or height-wise direction (Y direction) of the land
11
and lead terminal
21
. The Y direction is perpendicular to a direction along which terminals are arranged. When the shorter base edge
28
of the land
11
is placed outward from the longer base edge
18
of the lead terminal
21
, the imposed-on-the-land portion of outline of the lead terminal
21
becomes short-sized. Thus, the fringe portion for the fillet
5
becomes short-sized, to make the fillet
5
be difficult to be recognized.
When size of the lead terminal
21
is larger than that of the lands
11
, in particular, the lead terminal
21
would cover the land
11
almost entirely. In this way, the imposed-on-the-land portion of outline of the lead terminal
21
would become only tiny bits along legs or oblique edges of the lead terminal
21
. Thus, the fillet
5
becomes difficult to be recognized. Moreover, no visible fillet is found on shorter-base-edge-side of the land
11
, on which outline of the land
11
is totally covered by the lead terminal
21
. Thus, it is impossible to evaluate whether the bonding between the land
11
and the lead terminal
21
on the shorter-base-edge-side of the land
11
is good or not.
FIG. 6
shows further example of the conventional structure for connecting terminals, as designated as Prior Art 3.
In the construction shown in the
FIG. 6
, near-square-form rectangular lands
11
are arranged on a wiring board while planar-dumbbell-shaped lead terminals
21
are respectively superimposed on the lands
11
. Each lead terminal
21
has larger length-wise dimension and smaller width-wise dimension than those of respective land
11
, which are dimensions of long edges
13
,
14
and short edges
12
of the rectangular land
11
. Along long-edge-corresponding portions
23
,
24
of the each lead terminal
21
both on right-hand side and on left-hand side, arc-shaped recesses
25
are formed. Thus, two short-edge-corresponding portions
22
of the each lead terminal
21
are placed outward from short edges
12
of the respective land
11
. Meanwhile, the long-edge-corresponding portions
23
,
24
of the each lead terminal
21
are inwardly placed than the long edges
13
,
14
of the respective land
11
. Therefore, recesses
25
both on right-hand side and on left-hand side are placed on the land
11
.
Fillets
5
, which are recognizable from upper side through a wiring board arranged with the lead terminals
21
, are formed on long-edge-corresponding portions
23
,
24
including recesses
25
.
The structure shown in the
FIG. 6
is disadvantageous because recognition of the fillets
5
would become difficult when position of the lead terminals
21
is deviated in width-wise direction (X direction) of the lands
11
and lead terminals
21
. By such deviation, on either of right-hand side or left-hand side of the lead terminal
21
, the fillet
5
is formed only along a recess
25
. The distance between a recess
25
and a long edge
13
becomes so small by such deviation, that recognition of the fillets
5
becomes difficult on either of right-hand side or left-hand side.
The long edges
13
,
14
of the each land
11
may be designed to be sufficiently distanced outward from the long-edge-corresponding portions
23
,
24
. However, such design reduces the ratio of superimposed area for the bonding between the land
11
and the lead terminal
21
in terminals-arranging areas on wiring boards.
BRIEF SUMMARY OF THE INVENTION
In view of the above drawbacks, the present invention is aimed to provide a structure for connecting terminals on a wiring board, which structure enables easy evaluation by recognition of the fillets whether bonding of terminals by solder or the like is good or not, while keeping ratio of superimposed area between terminals as sufficiently high among terminal arranging area on a wiring board or other substrate.
According to present invention, a structure for connecting terminals on a wiring board comprising: first terminals arranged on a first substrate; rectangular second terminals arranged on a second substrate and respectively superimposed on first terminals; conductive bonding means electrically and mechanically connecting each of the first terminals to respective one of the second terminals; fillets of the conductive bonding means formed along fringe portions of the each first terminal outwardly protruding from outline of the respective second terminal; a recess being formed on outline of the each first terminal and intersecting with first edge of the respective second terminal; a bump formed on the outline of the each first terminal and intersecting with second edge, opposed to said first edge, of the respective second terminal.
This feature assures a reliable recognition of fillets of the conductive bonding means that connects the first and second terminals.
The conductive bonding means is typically a solder formed of metal alloy. Nevertheless, the conductive bonding means encompasses electro conductive resin pas
Kabushiki Kaisha Toshiba
Nguyen Khiem
Pillsbury & Winthrop LLP
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