Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
2001-02-23
2002-11-19
Epps, Georgia (Department: 2873)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S078000
Reexamination Certificate
active
06481902
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is related to Japanese applications Nos. 2000-048806 and 2000-238586, filed on Feb. 25, 2000 and Aug. 7, 2000 whose priorities are claimed under 35 USC § 119, the disclosures of which are incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a light transmission device, in particular to a light transmission device provided for AV equipments and optical data transmission devices to allow light transmission by optically coupling an optical fiber cable inserted in an insertion hole of a holder and an optical element held in the insertion hole.
2. Description of Related Art
In recent years, transmission of digital signals through optical communication has been commonly carried out in consumer products. When the product is not used, a protective structure against dust, flux used for assembling a substrate and other foreign objects is provided for an optical/mechanical junction between a light emitting/receiving section of the product and a plug of an optical fiber cable.
FIGS.
8
(
a
) to
9
(
b
) illustrate a schematic structure of a first light transmission device according to the prior art in which a protective cap is utilized as such a protective structure. FIG.
8
(
a
) is a side view and FIG.
8
(
b
) is a front view observed from an open end of a plug insertion hole, both showing the state where the protective cap is inserted (shutter closed state). FIGS.
9
(
a
) is a front view observed from the open end of the plug insertion hole and FIG.
9
(
b
) is a side view, both showing the state where the protective cap is extracted (shutter opened state).
The first light transmission device according to the prior art shown in FIGS.
8
(
a
) to
9
(
b
) includes in a holder
100
an optical element for performing at least either emitting or receiving light. When the device is not used, a protective cap
101
is inserted in a plug insertion hole
12
. The protective cap
101
is inserted/extracted along the direction of an arrow described in FIG.
9
(
b
). That is, the plug insertion hole
102
of the light transmission device is completely shut by the protective cap
101
when the device is not used, i.e., when a plug of an optical fiber cable is not inserted in the plug insertion hole
12
, so that entering of dust and foreign objects can be prevented.
However, the protective cap
101
requires a projected portion so that one can hold it, which makes the cap larger. Further, the protective cap
101
must be extracted to insert the optical fiber cable and the extracted protective cap
101
must be stored since it has to be re-inserted when the device is not used, which involves a possibility that children might swallow the cap if it is kept in a wrong place.
In connection with the above problem, FIGS.
10
(
a
) to
11
(
b
) schematically show a second light transmission device according to the prior art which does not use the protective cap
101
but employs a shutter
201
which opens outwardly. FIG.
10
(
a
) is a side view and FIG.
10
(
b
) is a front view observed from an open end of a plug insertion hole, both showing the state where the shutter
201
is closed. FIG.
11
(
a
) is a front view observed from the open end of the plug insertion hole and FIG.
11
(
b
) is a side view, both showing the state where the shutter
201
is opened.
The light transmission device includes in a holder
200
an optical element for performing at least either emitting or receiving light. When the device is not used, the plug insertion hole
202
of the light transmission device is shut and protected by the shutter
201
. That is, as shown in FIG.
11
(
b
), the shutter
201
is opened/closed along the direction of an arrow Y in accordance with the insertion/extraction of a plug
203
a
of an optical fiber cable
203
along the direction of an arrow X.
The shutter
201
eliminates the need of extracting the protective cap
101
to insert the optical fiber cable
203
. Further, since the shutter
201
is attached to the light transmission device, it is unnecessary to store it and the device is used without any harmful possibilities.
However, the shutter
201
must be opened outwardly by a person to insert the cable
203
, which is not so different from the first light transmission device. In some cases, he/she must close the shutter
201
if it remains opened after the plug
203
a
is extracted. Further, the size of the shutter
201
will be larger because a handle for opening/closing the shutter
201
is required.
FIGS.
12
(
a
) to
13
(
b
) schematically show a third light transmission device according to the prior art which does not use the protective cap
101
but employs a shutter
301
which opens inwardly. FIG.
12
(
a
) is a sectional side view and FIG.
12
(
b
) is a front view observed from an open end of the plug insertion hole, both showing the state where the shutter is closed. FIG.
13
(
a
) is a front view observed from the open end of the plug insertion hole and FIG.
13
(
b
) is a sectional side view, both showing the state where the shutter is opened.
The third light transmission device includes in a holder
300
an optical element
304
for performing at least either emitting or receiving light. When the device is not used, a plug insertion hole
302
of the light transmission device is shut and protected by the shutter
301
.
In this construction, a spring
305
having a pair of arms is provided with a pivot
306
. One of the arms contacts a rear surface of the shutter
301
and the other contacts an upper inner surface of the holder
300
, so that the shutter
301
automatically opens/closes by turning about the pivot
306
in accordance with the insertion/extraction of a plug
303
a
of an optical fiber cable
303
.
That is, the shutter
301
is closed so as to shut the plug insertion hole
302
when the device is not used. By pressing the plug
303
a
against the shutter
301
, the shutter
301
turns about the pivot
306
to open towards the inside of the holder
300
. When the plug
303
a
is extracted, the shutter
301
automatically returns to its original place by the returning force (elastic force) of the spring
305
.
Thus, disadvantages of the second light transmission device, i.e., the need of manual opening and closing of the outwardly opening shutter
201
and the increase of its size, are eliminated.
However, the third light transmission device has the following problems unsolved.
The above-illustrated plug
303
a
of the optical fiber cable
303
is in a cube shape and a pair of belt-shaped projections (engaging projections) each having a semicircle section is provided (
303
b
in FIG.
13
(
b
)). Further, as shown in FIGS.
14
(
a
) and
14
(
b
), a pair of grooves
307
(engaging grooves) each having a semicircle section is provided in the opposite inner walls of the plug insertion hole
302
of the light transmission device to engage with the projections
303
b
. FIGS.
14
(
a
) and
14
(
b
) are front views observed from an open end of the plug insertion hole of the third transmission device, showing the state where the shutter is closed and opened, respectively.
The projections
303
b
are engaged with the grooves
307
to insert the plug
303
a
to a desired position so that the optical element
304
accommodated in the holder
300
and an edge of the plug
303
a
of the optical fiber cable
303
where light is emitted (or received) are optically coupled.
The plug
303
a
is inserted in the plug insertion hole
302
of the holder
300
until the edge thereof contacts the optical element. Therefore, if the optical fiber cable
303
is narrowed as the projections
303
b
, the edge of the plug
303
a
and a lens of the optical element are damaged, which deteriorates the optical transmission.
In the third light transmission device, an axis of the spring
305
corresponds to the pivot
306
of the shutter
301
as shown in FIGS.
15
(
a
) and
15
(
b
). Further, as shown in FIG.
13
(
a
), a part of the shutter
301
coveri
Ikuta Mitsuhisa
Takaoka Takashi
Conlin David G.
Dike Bronstein, Roberts & Cushman IP Group, Edwards & Angell, LL
Epps Georgia
Hindi Omar
Sharp Kabushiki Kaisha
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