Radiant energy – Photocells; circuits and apparatus – Housings
Reexamination Certificate
2000-05-11
2002-09-03
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Housings
C257S081000
Reexamination Certificate
active
06444977
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electric member having a plurality of leads and a method of manufacturing the electric member.
2. Description of Related Art
A typical remote-controlled light receiving module
4
for receiving infrared light conveying a remote control signal from a remote commander is shown in
FIGS. 1A and 1B
.
Reference numeral
1
shown in the figures is a package having an approximately cubic shape. The package
1
is made of resin which can be penetrated by the infrared light. A remote-controlled receiver IC which is not shown in the figure is sealed inside the package
1
. Reference numeral
2
is a lens having a convex spherical surface created as an integrated part of the front surface of the package
1
. The lens
2
is fixed at a location which is optimum for focusing the infrared light modulated by the remote control signal at the remote commander on the light receiving surface of the remote-controlled receiver IC.
Reference numeral
3
denotes a lead protruding from the bottom surface of the package
1
in a direction perpendicular to the bottom surface. In the conventional remote-controlled light receiving module
4
, the shapes and the sizes of the sectional surfaces of the leads
3
are uniform at least at the bottom surface of the package
1
from which the leads
3
protrude. The leads
3
are created so as to exchange straight out from the bottom surface of the package
1
.
Such a remote-controlled light receiving module
4
is used in remote-controlled equipment such as a television receiver, tape recorder and air conditioner. Speaking in concrete terms, it is necessary to insert the external tips of the leads
3
of the remote-controlled light receiving module
4
into predetermined lead inserting through holes on a printed wiring board and solder the leads to wires on the board.
FIG. 2
shows how the conventional remote-controlled light receiving module
4
is typically mounted on a printed wiring board. Reference numeral
5
shown in the figure is the printed wiring board whereas reference numerals
6
each denote a lead inserting through hole created on the printed wiring board
5
for inserting a lead
3
. Reference numeral
7
denotes a piece of solder for connecting a lead
3
inserted into a lead inserting through hole
5
to wiring on the printed wiring board
5
.
Reference numeral
8
is a socket for enclosing the remote-controlled light receiving module
4
. The socket
8
serves as a component for fixing the position of the remote-controlled light receiving module
4
, in particular, the height of the remote-controlled light receiving module
4
above the surface of the printed wiring board
5
. In addition, the socket
8
is also used for fixing the orientation of the remote-controlled light receiving module
4
, in particular, the direction of the optical axis thereof. That is to say, since the remote-controlled light receiving module
4
exhibits a directivity characteristic, the position and the optical axis thereof are very important factors which affect the way the infrared light is received from a remote commander modulated by a remote control signal of an optical apparatus. It is thus necessary to install the remote-controlled light receiving module
4
on the printed wiring board
5
in a way determined in advance.
As described earlier, in the case of the conventional remote-controlled light receiving module
4
shown in
FIG. 1
, the shapes and the sizes of the sectional surfaces of the leads
3
are uniform at least at the bottom surface of the package
1
from which the leads
3
protrude. The leads
3
are created so as to stretch straight out off the bottom surface of the package
1
. Therefore, even with the leads
3
inserted into the lead inserting through holes
6
, the conventional remote-controlled light receiving module
4
is still shaky to a certain degree due to a gap existing between the conventional remote-controlled light receiving module
4
and the printed wiring board
5
. As a result, the position and orientation of the conventional remote-controlled light receiving module
4
relative to the printed wiring board
5
are not truly fixed. For this reason, loosening and a positional shift are generated inevitably in the conventional remote-controlled light receiving module
4
. Loosening refers to an inclination or slope of the optical axis relative to a set direction. Such a slope is undesirable in an optical system. It is needless to say that the positional shift is also undesirable as well. In order to avoid such loosening and such a positional shift, the socket
8
is used for firming the position and the orientation of the remote-controlled light receiving module
4
.
The socket
8
has an installation pin
9
to be inserted into a lead inserting through hole
6
. Reference numeral
10
is a hook nail
10
formed at the end of the installation pin
9
for hooking the installation pin
9
at the back surface (or the surface on the side not facing the socket body) of the printed wiring board
5
. Reference numeral
11
is a stopper created on the installation pin
9
at a position separated from the hook nail
10
at the end of the installation pin
9
by a distance about equal to the thickness of the lead inserting through hole
6
. The stopper
11
is used for hooking the installation pin
9
on the front surface (or the surface on the side facing the socket body) of the printed wiring board
5
. By hooking the installation pin
9
on the printed wiring board
5
by means of the stopper
11
and the hooking nail
10
, the position, particularly the height above the printed wiring board
5
, and the orientation of the socket
8
itself are fixed. The socket
8
, in turn, firmly sustains the position and orientation of the remote-controlled light receiving module
4
. That is to say, the position and orientation of the remote-controlled light receiving module
4
relative to the printed wiring board
5
are fixed in a prescribed manner using the socket
8
. At this position and in this orientation, the leads
3
of the remote-controlled light receiving module
4
are soldered to wiring on the printed wiring board
5
.
The problems described below are encountered because the position and orientation of the conventional remote-controlled light receiving module
4
shown in
FIGS. 1A and 1B
are fixed by using the socket
8
.
First of all, there is a problem that the cost is increased by the use of the socket
8
.
To be more specific, efforts need to be made to reduce the number of components and the number of assembly operations in response to a very strong demand for low-cost remote-controlled equipment such as a television set. In spite of such a demand, the conventional remote-controlled light receiving module
4
employs the socket
8
merely for firming the position thereof. The use of the socket
8
cannot thus be tolerated.
A second problem is that, since the position of the remote-controlled light receiving module
4
is fixed by the socket
8
through dip soldering, the leads
3
are pulled by the tensile stress of the solder
7
during dip soldering, giving rise to a problem that stress is applied to an IC pellet die-bonded to one of the leads
3
. It should be noted that the IC pellet itself which is embedded inside the package
1
is not shown in the figure. This problem is described in more detail as follows.
With the position of the conventional remote-controlled light receiving module
4
fixed by the socket
8
, the leads
3
are soldered by using dip-soldering technique. As the solder
7
becomes cool, it shrinks. The shrinking force pulls the leads
3
in a direction indicated by an arrow a shown in FIG.
2
.
Since the position of the package
1
is fixed by the socket
8
, however, the leads
3
cannot move in the direction indicated by the arrow a. As a result, the leads
3
are inevitably pulled out away from the package
1
downward to the lower side shown in FIG.
2
. The IC pellet die-bonded to one of the leads
3
, in
Le Que T.
Maioli Jay H.
Sony Corporation
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