Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
2001-12-10
2004-03-30
Healy, Brian (Department: 2874)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S014000, C385S088000, C385S094000, C359S350000, C398S140000, C398S164000, C264S001100, C438S026000, C438S027000, C257S098000
Reexamination Certificate
active
06712529
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an infrared data communication module used for performing infrared data communication by IrDA (Infrared Data Association) method.
BACKGROUND ART
Infrared data communication modules (hereinafter simply referred to as “module”) based on the IrDA are increasingly used for notebook-size personal computers, and recently also for mobile phones and electronic organizers. A module of this kind incorporates, in one package, not only an infrared light emitting element and an infrared light receiving element but also an IC chip for controlling these elements for enabling wireless communications between the above-described electronic apparatuses or between such an apparatus and a peripheral device such as a printer. In such a module, the communication speed and the communication distance are standardized in accordance with the versions, and attempts are being made to enhance the infrared data communication performance. On the other hand, there is an increasing demand for a size-reduction of the module, as a whole. Further, the manufacturing process requires a high dimensional accuracy and a cost reduction.
A prior art infrared data communication module of this kind is shown in FIG.
17
.
FIG. 18
illustrates the internal structure of the infrared data communication module of
FIG. 17
, whereas
FIG. 19
is a sectional view taken along lines XIX—XIX of FIG.
17
. As shown in
FIG. 17
, the prior art module
100
comprises a substrate
101
having a surface
101
a
for mounting a group E of components, and a molded body
5
formed from a molding resin integrally on the substrate
101
. The group E of components includes a light emitting element
2
, a light receiving element
3
and an IC chip
4
. As shown in
FIG. 19
, the light emitting element
2
, the light receiving element
3
and the IC chip
4
are respectively covered with protective members
6
within the molded body
5
.
The light emitting element
2
, which is an infrared emitting diode capable of emitting infrared light, has a rectangular configuration provided by cutting a semiconductor wafer including a light emitting layer. The light emitting element
2
is provided, at the bottom surface thereof, with a full electrode formed of gold, and is mounted on the substrate
101
with the full electrode oriented downward. The light emitting element
2
is formed, on the upper surface opposite to the full electrode, with a partial electrode formed of gold. Of the light emitted from the light emitting layer, the light emitted upward through the upper surface of the light emitting element
2
is mainly utilized to provide signals for data communication. In this prior art module, the light receiving element
3
is formed of a PIN photo diode capable of detecting infrared light and has an upper surface formed with a plurality of electrodes. The IC chip
4
controls the infrared emission and reception of the light emitting element
2
and the light receiving element
3
, respectively and has an upper surface formed with a plurality of electrodes.
As shown in
FIG. 18
, the substrate
101
is formed of an insulating material such as a glass fiber-reinforced epoxy resin and generally rectangular as viewed in plan. One of the longitudinal edges of the substrate
1
is formed with a plurality of inwardly convex semi-cylindrical terminals
19
. The surface
101
a
of the substrate
101
is provided with a predetermined wiring pattern P or the like which is electrically connected to the terminals
19
and formed by etching a conductive film.
After the mounting onto the surface
101
a
of the substrate
101
at predetermined positions, the group E of components, particularly the light receiving element
3
and the IC chip
4
, are electrically connected, via gold wires W, to wire-bonding pads
7
forming part of the wiring pattern P by first bonding and second bonding. Specifically, in the first bonding, a gold wire is introduced into a jig called capillary so that the tip end of the wire projects outward from the tip end of the capillary, and the tip end of the wire is melted by heating with hydrogen flame to form a gold ball. Then, by moving the capillary, the gold ball is pressed onto the electrode of the light receiving element
3
(or the IC chip
4
) for fixation thereto, thereby completing the first bonding. In the second bonding, the gold wire is extended out of the capillary and guided toward the wire bonding pad
7
with the tip end of the gold wire, i.e. the gold ball fixed. The gold wire is then pressed against the upper surface of the wire bonding pad
7
utilizing the tip end of the capillary while applying ultrasonic vibrations thereto, thereby second-bonding the wire. When the gold wire is fixed under pressure onto the wire bonding pad
7
, the gold wire is pressed and cut while slidably moving the capillary. Thus, the wire bonding step is completed. The wire bonding pads
7
are formed by plating part of the wiring pattern P (conductive film) with gold to provide good conduction with the gold wires W. In this way, each of the light receiving element
2
and the IC chip
4
is connected to the corresponding terminals
19
.
The connection between the light emitting element
2
and the IC chip
4
(and between the light receiving element
3
and the IC chip
4
) is carried out by wire bonding. However, when these elements are directly connected to each other, either the light emitting element (light receiving element
3
) or the IC chip
4
is pressed by the capillary in the wire bonding and may be therefore broken. Moreover, since each of the electrodes of the light emitting element
2
(light receiving element
3
) and the IC chip
4
is extremely small, it may not be possible to fix a gold wire to the electrode with a large contact area in the second bonding, which may lead to the deterioration of the data communication performance of the infrared data communication module
100
. Therefore, as shown in
FIG. 18
, for preventing the breakage of the elements and the deterioration of the data communication performance, the connection between the light emitting element
2
and the IC chip
4
and between the light receiving element
3
and the IC chip
4
is carried out via jumper pads
11
a
,
11
b
of a relatively large surface area formed on the surface
101
a
of the substrate
101
instead of directly connecting these elements. Specifically, the light emitting element
2
is connected to the jumper pad
11
a
by wire bonding, whereas the IC chip
4
is connected to the jumper pads
11
a
and
11
b
by wire bonding.
Similarly to the die bonding pad, the jumper pads
11
a
,
11
b
are formed by plating a conductive film with gold to provide a good conductivity with the gold wires. Specifically, the jumper pad
11
a
(jumper pad
11
b
) is obtained by forming a plating conductive pattern
112
a
(plating conducive pattern
112
b
) from a conductive film on the surface
101
a
of the substrate
101
followed by applying a gold foil to the conductive pattern
112
a
at the region to become the jumper pad
11
a
(jumper pad
11
b
) by flowing a current through the plating conductive pattern
112
a
(plating conductive pattern
112
b
). The plating conductive patterns
112
a
,
112
b
are formed at the same time as forming the wiring pattern P.
As shown in
FIG. 18
, the connection between the light emitting element
2
and the terminal
19
is performed by bonding the light emitting element
2
onto the die bonding pad
113
electrically connected to the terminal
19
. The die bonding pad
113
is formed by plating a conductive film with gold to provide a good conductivity with the full electrode formed on the bottom surface of the light emitting element
2
. Specifically, the die bonding pad
113
is obtained by forming an LED conductive pattern
114
from a conductive film on the surface
101
a
of the substrate
101
followed by applying a gold foil to part of the LED conductive pattern
114
by electroplating by flowing a current through the LED conductive pattern
114
. Similar
Healy Brian
Merchant & Gould P.C.
Petkovsek Daniel
Rohm & Co., Ltd.
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