Semiconductor device manufacturing: process – Making device or circuit emissive of nonelectrical signal – Having diverse electrical device
Reexamination Certificate
2000-01-21
2001-02-27
Picardat, Kevin M. (Department: 2822)
Semiconductor device manufacturing: process
Making device or circuit emissive of nonelectrical signal
Having diverse electrical device
C438S024000, C438S026000
Reexamination Certificate
active
06194238
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a photosensitive semiconductor device, and particularly to a photocoupler having a photo-emitting device and a photo-detecting device shaped in integral form.
2. Description of the Related Art
FIG. 4
is a view showing a section structure of a previously-used photocoupler. The prior art photocoupler will be explained below with reference to FIG.
4
.
In
FIG. 4
, reference numerals
1
and
2
indicate a lead frame on the photo- or light-emission side and a lead frame on the photo- or light-reception side, respectively. A light- or photo-emitting device
3
and a light- or photo-receiving or -detecting device
4
are fixed to islands of the lead frames
1
and
2
respectively. Designated at numeral
5
shown in
FIG. 4
is a light-transmissive or translucent resin, which couples the photo-emitting device
3
and the photo-detecting device
4
to each other in an opposed state. Further, they are resin-sealed with an epoxy molding resin to prevent external random light.
FIGS.
5
(A) and
5
(B) are respectively views showing configurations of conventional lead frame
1
on the light-emission side and lead frame
2
on the light-reception side.
FIG. 6
is a view illustrating the manner of charging of the translucent resin
5
. A method of manufacturing the photocoupler shown in
FIG. 4
will be explained below with reference to
FIGS. 5 and 6
.
A photo-emitting device
3
and a photo-detecting device
4
are fixed to diagonally-shaded regions of islands of the lead frames shown in FIGS.
5
(A) and
5
(B).
Thereafter, the lead frame
1
with the photo-emitting device
3
placed thereon and the lead frame
2
with the photo-detecting device
4
placed thereon are placed as opposed to each other as shown in FIG.
6
. In this condition, the translucent resin
5
is filled between the lead frame
1
and the lead frame
2
from diagonally above the lead frame
1
by the use of a dispenser
7
to thereby couple the photo-emitting device
3
and the photo-detecting device
4
to each other.
Thereafter, the whole part is plastic-sealed with a mold sealing material
6
to create the photocoupler shown in FIG.
4
.
However, the conventional photocoupler has a problem in that upon fabrication of the photocoupler, the translucent resin
5
to be filled adheres to an upper surface (corresponding to a surface not opposed to the lead frame
2
on the light-emission side) of the lead frame
1
due to a subtle position displacement of the dispenser
7
for filling the translucent resin
5
(this state is indicated by a circle mark in FIG.
6
).
As a result, the shape of the translucent resin
5
varies according to the position of the dispenser
7
. This type of photocoupler has a problem in that since light reflected from an interface between the translucent resin
5
and the molding resin
6
is detected by the photo-detecting device
4
, the efficiency of light transmission by the photocoupler varies as the translucent resin
5
changes in shape.
Further, a problem also arises in that the adhesion between the lead frame
1
and the molding resin
6
is deteriorated due to the attachment of the translucent resin
5
to the upper surface of the lead frame
1
.
SUMMARY OF THE INVENTION
With the foregoing problems in view, it is therefore an object of the present invention to prevent deterioration of adhesion between a molding resin and a lead frame and a light transmission characteristic due to the adhesion of a translucent resin to an upper surface of the lead frame upon charging a photocoupler with the translucent resin.
According to one aspect of this invention, for achieving the above object, there is provided a photosensitive semiconductor device comprising a first lead frame having a first island to which a photo-emitting semiconductor device is fixed, a second lead frame having a second island to which photo-detecting semiconductor device is fixed, a translucent resin for coupling the photo-emitting semiconductor device and the photo-detecting semiconductor device to each other in an opposed state, a sealing material for surrounding the translucent resin, and a concave portion defined in either one of ends of the first and second islands.
Typical ones of various inventions of the present application have been shown in brief. However, the various inventions of the present application and specific configurations of these inventions will be understood from the following description.
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Jones Volentine, L.L.C.
OKI Electric Industry Co., Ltd.
Picardat Kevin M.
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