Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2000-08-31
2003-09-23
Cuneo, Kamand (Department: 2827)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S764000
Reexamination Certificate
active
06625036
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an infrared data communication module for performing data communication under so-called IrDa (Infrared Data Association).
BACKGROUND ART
An infrared data communication module for operation under IrDA is commonly used in the field of notebook personal computers, and recently, it is also used in a mobile phone or an electronic scheduler for example. Such an infrared data communication module includes an infrared LED, a photodiode and a modem circuit as enclosed in a single package for performing two-way wireless communication.
While the communication performance of the infrared data communication module is enhancing, there is an increasing demand for size reduction of the infrared data communication module. Moreover, dimensional accuracy is strictly required in manufacturing the infrared data communication module.
FIGS. 20 and 21
illustrate an example of prior-art method of making infrared data communication modules. According to the prior art method, use is made of a strip-like or rectangular substrate
1
e
on which plural sets of infrared light emitting elements
2
e
and infrared light receiving elements
3
e
are arranged in rows and then sealed in resin packages
4
e.
In such a method, the number of the resin packages
4
e
is the same as the number of the sets of light emitting elements
2
e
and light receiving elements
3
e
, so that each resin package separately encloses a respective set of light emitting element
2
e
and light receiving element
3
e
. After the resin-packaging, the substrate
1
e
is cut at positions indicated by phantom lines L
1
, L
2
, thereby providing a plurality of infrared data communication modules.
However, the above-described conventional manufacturing method has the following problems.
According to the conventional method, a resin package
4
e
is provided separately for each set of light emitting element
2
e
and light receiving element
3
e
. This leads to an increase in the total number of the resin packages
4
e
while also increasing the number of clearances
90
provided between the resin packages
4
e
, thereby wasting the space of the substrate
1
e
. As a result, the number of infrared data communication modules obtainable from the substrate
1
e
of a given size decreases, which leads to an increase in the manufacturing cost of the infrared data communication modules.
To solve the problem described above, the inventor of the present invention has previously conceived the idea of causing a single resin package to enclose, on the substrate
1
e
, a group of components including plural sets of light emitting elements
2
e
and light receiving elements
3
e
. With such a method, it is possible to minimize the number of the resin packages for eliminating the wasted space (clearances
90
) between the resin packages.
With the above measure, however, the resin package comes into intimate contact with the substrate
1
e
over a large surface area. Therefore, in the case where the substrate
1
e
has a small thickness or is made of a relatively soft material, the substrate
1
e
warps, consequently distorting the infrared data communication modules obtained from the substrate.
Further, as shown in
FIG. 22
, use is made of mold members P
1
, P
2
for molding a resin package
4
e
to seal a light emitting element
2
e
and a light receiving element
3
e
on a substrate
1
e
. Specifically, the head mold member P
1
having a configuration for defining the configuration of the resin package
4
e
presses against the obverse surface of the substrate
1
e
, whereas the tail mold member P
2
which has a flat pressing surface presses against the reverse surface of the substrate
1
e
. Then, with the tail mold member P
2
held in intimate contact with the reverse surface of the substrate
1
e
, resin is injected between the head mold member P
1
and the obverse surface of the substrate
1
e
for solidification into the resin package
4
e.
The substrate
1
e
is formed with through-holes
7
extending thicknesswise. The substrate
1
e
is further formed, on the reverse surface thereof, with terminals
71
connected to the through-hole
7
, respectively. Since each of the terminals
71
made of a thin conductor film has a certain thickness, the reverse surface of the substrate
1
e
may become irregular. Therefore, the tail mold member P
2
may not come into intimate contact with the substrate
1
e
, and the surface pressure against the reverse surface of the substrate
1
e
may be insufficient around the through-holes
7
. As a result, a clearance may be formed between the reverse surface of the substrate
1
e
and the tail mold member P
2
. When resin is filled between the head mold member P
1
and the substrate
1
e
in such a condition, the resin may flow via the through-holes onto the reverse surface of the substrate
1
e
. As a result, resin may be deposited on the reverse surface of the substrate
1
e.
Moreover, before the sealing step and the cutting step described above, a predetermined conductor pattern (not shown) and the terminals
71
are formed on the obverse and the reverse surfaces of the substrate
1
e
, respectively, by photolithography for example. Specifically, a resist material is applied on the substrate
1
e
which is initially formed with a copper film on a surface thereof. Then, a mask having a predetermined pattern disposed on the substrate which is then subjected to light exposure, development and etching for removing unnecessary portions of the copper film.
Then, an insulating layer (not shown) called “green resist” is formed on the substrate
1
e
to cover portions of the substrate other than the conductor pattern and the terminals
71
which are to be exposed. For forming such an insulating layer, a similar mask is utilized for light exposure. At this time, if the mask positionally deviates, the exposed area of the conductor pattern and the terminals
71
may become small.
An infrared data communication module A may be mounted on a module mounting board
9
so that the reverse surface of the substrate
1
e
extends perpendicularly to an obverse surface of the module mounting board
9
, as shown in FIG.
23
. In this case, the terminals
71
on the reverse surface of the substrate and a wiring pattern P formed on the module mounting board
9
are bonded together solder.
However, if the exposed portions for the terminals
71
are small as described above, solder fillets are not sufficiently formed or likely to be easily detached. Therefore, the terminals
71
of the infrared data communication module and the wiring pattern P of the module mounting board
9
are not reliably connected.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a method of making an infrared data communication modules which is capable of eliminating or lessening the problems described above while also providing such an infrared data communication module.
In accordance with a first aspect of the present invention, there is provided a method of making infrared data communication modules comprising the steps of: forming predetermined wiring patterns on an obverse and a reverse surfaces of a substrate; mounting, on one of the surfaces of the substrate, a group of components including plural sets of light emitting elements and light receiving elements; resin-packaging the group of components mounted on the substrate; and dividing the resin-packaged components into a plurality of infrared data communication modules each of which includes a respective set of light emitting element and light receiving element; wherein the resin-packaging step comprises forming a plurality of mutually separated resin packages each of which collectively seals at least two sets of light emitting elements and light receiving elements.
According to this method, the number of the resin packages needed is smaller than the number of the sets of light emitting elements and light receiving elements. Therefore, the number of clearances provided between the resin packages can be reduced so that the total
Bednarek Michael D.
Cuneo Kamand
Dinh Tuan
Rohm & Co., Ltd.
Shaw Pittman LLP
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