Radiant energy – Photocells; circuits and apparatus – Housings
Reexamination Certificate
1999-12-07
2003-09-30
Pyo, Kevin (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Housings
C250S216000, C250S208100, C257S680000
Reexamination Certificate
active
06627872
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a semiconductor optical sensing apparatus including a semiconductor optical sensor chip.
The conventional semiconductor optical sensing apparatus includes a semiconductor optical sensor chip, such as a charge coupled device (CCD) and a metal oxide semiconductor (MOS) device, enclosed in a ceramic casing for practical use. The semiconductor optical sensor chip detects an image or images focused onto it through an aspherical glass lens.
FIG.
20
(
a
) is a plan view of a conventional semiconductor optical sensing apparatus. FIG.
20
(
b
) is a cross sectional view taken along line
20
b
—
20
b
of FIG.
20
(
a
). FIG.
21
(
a
) is a plan view of another conventional semiconductor optical sensing apparatus. FIG.
21
(
b
) is a cross sectional view taken along line
21
b
—
21
b
of FIG.
21
(
a
). FIG.
22
(
a
) is a plan view of a further conventional semiconductor optical sensing apparatus. FIG.
22
(
b
) is a cross sectional view taken along line
22
b
—
22
b
of FIG.
22
(
a
).
In these figures, the optical sensing apparatus includes a sensor chip, an aspherical glass lens combined with the sensor chip and a ceramic casing that houses the sensor chip and the aspherical glass lens. The sensor chip may be a CCD image sensor, an MOS image sensor, a photodiode, an ultraviolet ray sensor or other optical sensors.
Referring now to FIGS.
20
(
a
) and
20
(
b
), the semiconductor optical sensing apparatus includes a detecting section and an optical section. The detecting section includes a semiconductor optical sensor chip
111
, a ceramic casing
112
, lead frames
113
, bonding wires
114
and a transparent plate
116
. The sensor chip
111
is die-bonded to the casing
112
. The lead frames
113
include lead pins. The bonding wires
114
connect the internal terminals of the sensor chip
111
and the lead frames
113
. The transparent plate
116
is fixed to the open end of the casing
112
with a layer
115
of glass having a low melting point or of adhesive.
The sensor chip
111
is mounted on the inner bottom face of the casing
112
and sealed in the casing
112
by the transparent plate
116
. The space enclosed by the casing
112
and the transparent plate
116
is filled with a transparent filler (not shown) or with gas. The detecting section is fixed to a printed circuit board
117
by soldering the lead frames
113
to the printed circuit board
117
.
The optical section includes an aspherical glass lens
118
, a lens fixing frame
120
and a pressing metal jig
121
. The lens fixing frame
120
is fixed to the printed circuit board
117
with an adhesive
119
so that the aspherical glass lens
118
may focus an image or images onto the sensor chip
111
. The pressing metal jig
121
fixes the aspherical glass lens
118
to the lens fixing frame
120
.
The semiconductor optical sensing apparatus thus constructed detects an image or images focused by the aspherical glass lens
118
on the sensor chip
111
through the transparent plate
116
, and outputs the detected image signals through the lead frames
113
. The semiconductor optical sensing apparatus works as an image sensor.
Referring now to FIGS.
21
(
a
) and
21
(
b
), the semiconductor optical sensing apparatus includes an optical section, that is different from the optical section of the semiconductor optical sensing apparatus shown in FIGS.
20
(
a
) and
20
(
b
). In FIGS.
21
(
a
) and
21
(
b
), the optical section includes an aspherical glass lens
118
, a lens fixing frame
124
and a pressing metal jig
125
. The lens fixing frame
124
is fixed to the printed circuit board
117
by frame support columns
122
and screws
123
so that the aspherical glass lens
118
may focus an image or images onto the sensor chip
111
. The pressing metal jig
125
fixes the aspherical glass lens
118
to the lens fixing frame
124
.
Referring now to FIGS.
22
(
a
) and
22
(
b
), the semiconductor optical sensing apparatus includes an optical section different from the optical section of the semiconductor optical sensing apparatus shown in FIGS.
20
(
a
) and
20
(
b
). The semiconductor optical sensing apparatus of FIGS.
22
(
a
) and
22
(
b
) is different from the optical sensing apparatus of FIGS.
20
(
a
) and
20
(
b
) in that the detecting section and the optical section are integrated together in FIGS.
22
(
a
) and
22
(
b
).
In FIGS.
22
(
a
) and
22
(
b
), the optical section includes an aspherical glass lens
118
, a lens fixing frame
126
, an adhesive layer
127
and a pressing metal jig
128
. The aspherical glass lens
118
is mounted on the lens fixing frame
126
. The adhesive layer
127
bonds the lens fixing frame
126
to the transparent plate
116
of the detecting section. The pressing metal jig
128
fixes the aspherical glass lens
118
to the lens fixing frame
126
. The aspherical glass lens
118
is positioned so that the aspherical glass lens
118
may focus an image or images onto the sensor chip.
When the space inside the casing
112
is filled with gas, the surface of the semiconductor optical sensor chip and the bonding wires
114
are deteriorated depending on the gas in the sealed casing
112
. For avoiding the deterioration, it is necessary to fill the space inside the casing
112
with an inert gas. The filling of the space inside the casing
112
with the inert gas increases manufacturing steps. Even when the space inside the casing
112
is filled with the inert gas, it is necessary to control the temperature and humidity precisely so that the characteristics of the semiconductor optical sensing apparatus may not change. Moreover, the gas leakage test, that should be conducted after the space inside the casing
112
is filled with the inert gas, increases the manufacturing cost.
When the space inside the casing
112
is filled with a transparent filler (not shown) to protect the sensor chip
111
and to seal the casing
112
, the transparent filler expands or contracts due to temperature variations around and inside the casing
112
. The expansion and contraction of the filler cause parting between the casing
112
and the filler, bubbles in the filler, and in the worst case, breaking of the bonding wires
114
. The expansion and contraction of the filler due to temperature variations change the distance between the upper surface of the transparent plate
116
and the surface of the sensor chip
111
. The distance change further causes variation of the optical characteristics of the semiconductor optical sensing apparatus.
In the conventional CCD image pick-up apparatuses and the conventional MOS image pick-up apparatuses, a ceramic casing is combined with an aspherical glass lens to prevent the displacement of the focal point due to temperature variations. As shown in FIGS.
20
(
a
) through
22
(
b
), one or more aspherical glass lenses
118
are mounted on the lens fixing frame
120
,
124
or
126
and fixed to the lens fixing frame
120
,
124
or
126
by the pressing metal jig
121
,
125
or
128
. This structure increases the cost and labor for manufacturing the optical system.
When an insulative plastic casing and an aspherical plastic lens are employed to reduce the manufacturing costs of the optical system, the plastic casing also expands or contracts in response to expansion or contraction of the transparent filler. The expansion and contraction of the casing further cause larger displacement of the focal point, that is hazardous for obtaining a clear image.
In view of the foregoing, it is an object of the invention to obviate the above described problems of the conventional semiconductor optical sensing apparatuses.
It is another object of the invention to provide an economical semiconductor optical sensing apparatus having a simple structure, that is less affected by temperature variations.
It is a further object of the invention to provide a semiconductor optical sensing apparatus that facilitates preventing deterioration and variation of the optical characteristics, elongatin
FuKamura Hajime
Hirata Nobuo
Izumi Akio
Sugiyama Osamu
Fuji Electric & Co., Ltd.
Kanesaka & Takeuchi
Pyo Kevin
Sohn Seung C.
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