Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
2000-03-28
2002-01-29
Healy, Brian (Department: 2874)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S076000, C385S077000, C385S078000, C385S092000, C385S093000, C385S094000, C385S139000
Reexamination Certificate
active
06341898
ABSTRACT:
BACKGROUND OF THE INVENTION
(1). Field of the Invention
This invention relates to an optical connector for use in multiple transmission circuits mounted in vehicles such as motorcars, a receptacle composing the optical connector, and a process for producing the receptacle.
(2). Description of the Related Art
As an optical connector, in which a sleeve lies between an optical fiber and an optical element module (sometimes called as light-receiving/light-emitting module, receiver/transmitter module, or fiber optic transceiver (FOT)), an optical connector proposed by the present applicant in Japanese Utility Model Publication No. H6-33443 has been generally known.
A pair of the above sleeves
101
and optical connector
102
are shown in FIG.
14
.
Each sleeve
101
, which is mounted in a receptacle
103
(an equipment-side connector) composing an optical connector
102
, lies between a corresponding optical element module
104
(a light-emitting element module
104
or a light-receiving element module
104
) also mounted in the receptacle
103
and an corresponding optical fiber
106
(only one of two fibers shown in
FIG. 14
, hereinafter the same) mounted in an optical plug
105
(an optical fiber-side connector) that is plugged into the receptacle
103
to assemble the optical connector
102
. Thus, the sleeve
101
is regarded as a component of the optical connector, which is capable of making an optical connection between the optical element module
104
and the optical fiber
106
.
The optical connector
102
consists of the receptacle
103
and the optical plug
105
that is plugged into the receptacle
103
.
As shown in
FIGS. 14 and 15
, the receptacle
103
has a housing
107
made of synthetic resin, in which a pair of rooms
108
is provided to receive the corresponding optical element module
104
therein that is supported by a corresponding back sheet
109
consisting of resilient menber such as a rubber, the upper side of which is covered with a cap
110
. Under a pair of the rooms
108
, in each of which the corresponding optical element module
104
is received, a corresponding cylinder
112
is provided, which extends downward in such a manner that an axis of each cylinder
112
coincides with that of a corresponding lens
111
. The sleeve
101
is inserted into the corresponding cylinder
112
to be installed therein.
The sleeve
101
is constructed in such a manner that an optical fiber
113
(multiple-mode plastic optical fiber) consisting of a core and clad (not shown in the figures) is glued to be fixed into a cylindrical holder
114
and both end surfaces of the sleeve
101
is superfinely polished.
On the other hand, as shown in
FIGS. 14 and 16
, the optical plug
105
, which is plugged into the receptacle
103
, contains: a pair of ferrule assemblies
115
each covering the corresponding optical fiber
106
in such a manner that an end surface of the optical fiber
106
is exposed; a plug housing
117
having a cylindrical partition
116
that receives and protects a pair of the ferrule assemblies
115
therein; a spring cap
118
that is fitted to the plug housing
117
to be fixed there; and a boot
119
that is fitted into the lower part of the spring cap
118
.
In the plug housing
117
, there is formed a pair of shoulders
117
a, each of which is fitted to a corresponding flange
115
a
provided around the outer circumference of a lower portion of the corresponding ferrule assembly
115
and there is provided a pair of springs
120
, each of which lies between the corresponding flange
115
a
and a corresponding inner cylinder
118
a
of the spring cap
118
so as to constantly press the ferrule assembly
115
upward.
As shown in
FIG. 16
, when the flange
115
a
is engaged with the shoulder
117
a
, an end a of the ferrule assembly
115
, which corresponds to an end surface of the optical fiber
106
, never come out from a front end b of the plug housing
117
.
In the following, a connection between the receptacle
103
and the optical plug
105
is explained with reference to FIG.
14
.
When the optical plug
105
is plugged into the receptacle
103
, each cylinder
112
enters into the plug housing
117
and each ferrule assembly
115
simultaneously enters into the corresponding cylinder
112
. The ferrule assembly
115
abuts against an end of the cylinder
112
and the spring
120
gives a moderate contact pressure therebetween.
In the above situation, the end a (see
FIG. 16
) and the sleeve
101
are arranged making minimun gap therebetween, thereby a loss caused by gap is controlled to be minimal.
In the above prior art, the sleeve
101
and the optical element module
104
are severally installed into the housing
107
, causing a troublesome assembly process, inferior workability and high cost.
Further, the sleeve
101
and the optical element module
104
are separately constructed making a gap therebetween, causing a loss of light due to this gap as well as the above-mentioned loss of light due to the gap between the end a (see
FIG. 16
) and the sleeve
101
. These losses of light might affect optical communication.
Furthermore, the receptacle
103
is produced through the steps of: forming the housing
107
; producing the optical element module
104
; producing the sleeve
101
; forming the cap
110
; and assembling in sequence thus produced components into the receptacle
103
, causing too many steps and high cost thereby.
Further, the step of producing the optical element module
104
includes steps of producing a lead frame having the optical element and forming a molded portion, which protects the lead frame, using a transparent resin.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to solve the above problem and to provide a receptacle that is useful from the viewpoint of superior workability, low loss of light and low cost, and a process for producing the same. Another object of the present invention is to provide an inexpensive optical connector, which contributes for a better optical communication.
In order to accomplish the above object, a first aspect of the present invention is to provide a process for producing a receptacle, into which an optical plug having ferrule-mounted optical fibers at the end thereof is plugged, comprising the steps of: producing either one lead frame having an optical element, either a light-emitting element or a light-receiving element, or two lead frames consisting of one lead frame having a light-emitting element and another lead frame having a light-receiving element; forming a connector housing containing a socket cavity, into which the optical plug is plugged, a room for accommodating the lead frame and a cylinder being in communication therewith, wherein said cylinder is placed in such a manner that said cylinder is opposite to said end of the optical plug upon plugging of the optical plug into the socket cavity; forming a transparent, hollow and cylindrical clad on an inner circumferential surface of said cylinder after forming said connector housing; accommodating the lead frame into said room in such a manner that the optical element is placed on an axis of said cylinder in which the clad is formed; and producing an optical element module united with said connector housing by filling the inside of the clad and said room with a light-transmitting transparent resin having higher refractive index than that of the clad.
According to the first aspect of the present invention, the number of steps for producing a receptacle becomes small compared to that of a conventional process, enabling a reduction of cost as well as superior workability.
That is, by using the clad and the transparent resin filled therein, the optical element module itself functions as a conventional sleeve, saving a conventional process for making a sleeve. Accordingly, a superfine polishing for end surfaces of optical fibers, by fixing which into a cylindrical holder using glue, is not needed. Further, the optical element module is in one piece in a connector connector housing, resulting in tha
Armstrong Westerman Hattori McLeland & Naughton LLP
Healy Brian
LandOfFree
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