Electricity: conductors and insulators – Boxes and housings – Hermetic sealed envelope type
Reexamination Certificate
1998-11-18
2001-06-05
Cuchlinski, Jr., William A. (Department: 3661)
Electricity: conductors and insulators
Boxes and housings
Hermetic sealed envelope type
C174S050510, C174S050510, C257S698000, C257S699000, C257S708000
Reexamination Certificate
active
06242694
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a package for housing a photosemiconductor device being capable of hermetically sealing the photosemiconductor device and holding an optical fiber for transferring optical signals from and to the photosemiconductor device, and more particularly to a package for housing a photosemiconductor device provided with leads of a united-inner/outer-portions type.
2. Description of the Prior Art
FIG.
4
(
a
) is a plan view of a conventional package for housing a photosemiconductor device. FIG.
4
(
b
) is a sectional view taken along the line A—A of the package of FIG.
4
(
a
). In FIGS.
4
(
a
) and
4
(
b
) reference number
1
indicates a base plate composed of a metal material such as a copper-tungsten alloy or the like,
2
indicates a frame composed of a metal material such as an iron-nickel-cobalt alloy or the like, and
3
indicates a holder inserted into a side wall of said frame
2
in order to introduce an optical fiber into the inside of the frame
2
. Said frame
2
needs to be composed of a conductive material made of metal or the like for the purpose of radio-wave shielding or the like.
In FIG.
4
(
a
), indicates a united-inner/outer-portions type lead frame in which each lead has its inner lead portion and outer lead portion continuously formed into one body. Such a united-inner/outer-portions type lead frame
4
is composed of a metal material such as an iron-nickel-cobalt alloy, for example.
In FIGS.
4
(
a
) and
4
(
b
) indicates a strip portion forming one part of said lead frame
4
. And
4
a
indicates a plurality of united-inner/outer-portions type leads which form the other part of said lead frame
4
and each of which is formed so as to project from said strip portion
4
b.
Each of said plurality of united-inner/outer-portions type leads
4
a
is divided into an inner lead portion
4
a
1
and an outer lead portion
4
a
2
. The inner lead portion
4
a
1
is a portion of said united-inner/outer-portions type lead
4
a
to be introduced into the inside of said frame
2
. And the outer lead portion
4
a
2
is a portion of said united-inner/outer-portions type lead
4
a
to be outside said frame
2
.
As shown in FIGS.
4
(
a
) and
4
(
b
), said plurality of united-inner/outer-portions type leads
4
a
are inserted through a plurality of lead-inserted through holes
5
formed in a side wall of said frame
2
. And each of these inserted united-inner/outer-portions type leads
4
a
is joined to the frame
2
by means of sealing materials of glass
6
. The inside of said frame
2
is hermetically sealed by stopping up said plurality of lead-inserted through holes
5
with said sealing materials of glass
6
.
FIG. 5
shows an example of housing a photosemiconductor device in a package. In
FIG. 5
,
11
indicates a photosemiconductor device,
12
indicates an insulating plate made of ceramic on which the photosemiconductor device
11
is mounted,
13
indicates a frame made of metal in which the insulating plate
12
having the photosemiconductor device
11
mounted thereon is sealed,
14
indicates a plurality of united-inner/outer-portions type leads which are introduced into the inside of said frame
13
through a plurality of through holes formed in a side wall of this frame
13
, and
15
indicates an optical fiber introduced into the inside of said frame
13
through a hole formed in another side wall of said frame
13
. In the example shown in
FIG. 5
, a plurality of conductive patterns
30
on the insulating plate
12
and the inner lead portions of said plurality of united-inner/outer-portions type leads
14
are electrically connected with each other by means of soldering.
In FIGS.
4
(
a
) and
4
(
b
), the package for housing a photosemiconductor device provided with united-inner/outer-portions type leads secures insulation between said plurality of united-inner/outer-portions type leads
4
a
composed of a metal material such as an iron-nickel-cobalt alloy for example and said frame
2
composed of a metal material such as an iron-nickel-cobalt alloy for example, and secures airtightness of the inside of said frame
2
by stopping up said plurality of through holes
5
formed in a side wall of said frame
2
for inserting said plurality of united-inner/outer-portions type leads
4
a
through them with the sealing materials of glass
6
.
As described above, in the package for housing a photosemiconductor device shown in FIGS.
4
(
a
) and
4
(
b
), the frame
2
is made of a metal material such as an iron-nickel-cobalt alloy or the like, and the base plate
1
is made of a metal material such as a copper-tungsten alloy or the like.
In such a way, the conventional package for housing a photosemiconductor device is being put together by combining a plurality of components such as said frame
2
, said base plate
1
and the like which are made of different kinds of metal materials being different in thermal expansion coefficient from one another. When environmental tests including a thermal shock test and the like are applied to a conventional package for housing a photosemiconductor device, therefore, a problem often happens that said sealing materials of glass
6
are cracked due to strains generated in joint portions of a plurality of components made of said metal materials being different in thermal expansion coefficient from one another and airtightness of the inside of said frame
2
is impaired. Particularly, since said sealing materials of glass
6
are liable to be cracked by nature, they have a disadvantage of being more liable to be cracked under environmental tests including a thermal shock test and the like.
SUMMARY OF THE INVENTION
The present invention has been performed paying attention to the problem of the prior art, and an object of the invention is to provide a package for housing a photosemiconductor device provided with united-inner/outer-portions type leads, said package being capable of greatly improving the reliability of airtightness of the inside of its frame.
The present invention is a package for housing a photosemiconductor device, said package comprising: a plurality of united-inner/outer-portions type leads each of which has an inner lead portion and an outer lead portion continuously formed into one body; a conductive frame having an opening formed in said conductive frame for introducing the inner lead portions of said united-inner/outer-portions type leads into the inside of said conductive frame; and a ceramic plate has a side face for stopping up the opening of said side wall of said conductive frame, said ceramic plate having a plurality of through holes in said side face for inserting the inner lead portions of said plurality of united-inner/outer-portions type leads there through, said ceramic plate being joined with said conductive frame so that said side face stops up the opening of said conductive frame.
Further, in the package for housing a photosemiconductor device according to the present invention, said ceramic plate is joined with said conductive frame from the outside of said conductive frame.
Furthermore, in the package for housing a photosemiconductor device according to the present invention, a metalization layer for making it possible to join said ceramic plate to said conductive frame by means of a brazing material is formed on the edge of said side face of said ceramic plate to be joined to said conductive frame.
Still more, in the package for housing a photosemiconductor device according to the present invention, metalization layers for making it possible to join parts of the inner lead portions of said plurality of united-inner/outer-portions type leads to said ceramic plate by means of brazing materials are formed on the inside wall portions and on the peripheral portions of said plurality of through holes of said ceramic plate.
Yet more, in the package for housing the photosemiconductor device according to the present invention, projection-shaped stoppers for preventing said outer lead portions from being introdu
Armstrong Westerman Hattori McLeland & Naughton LLP
Cuchlinski Jr. William A.
Mancho Ronnie
Sumitomo Metal (SMI) Electronics Devices Inc.
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