Note: Descriptions are shown in the official language in which they were submitted.
~24549~
Fiber Optic Connector.
This invention relates to a fiber optic connector wnich
in particular is intended for applications where the probabi-
lity of contamination is high, for example in mili-tary equip-
ment or in offshore and underwater installations and certain
industries. A simple connecting operation and good protection
in disconnected condition is important in such applications.
The practical use of fiber optic systems requires detach-
able contacts for termination at a transmitter and a receiver.
In some applications there are also employed fiber optic con-
nectors for joining already terminated cable lengths. A long
transmission di~tance and a safe signal transmission requir~ a
minimum of transmission losses in the connectors.
The losses in fiber optic connectors are inter alia deter-
mined by the positioning accuracy and possible contaminations
in the connector. Connectors having lenses which collimate
and focus the light, require a lower longitudinal and transver
sal positioning accuracy, as for example described in EPC
patent application of Publication No. 0057794. Such a lens
system will also reduce the sensitivity of the connector with
respect to foreign particles in the light path. Anyhow, fiber
optic connectors will often be subject to contamination and
thereby increased transmission losses in the transmission.
In EPC Patent Application Publication 0024989 there are
described fiber optic connectors having movable covers which
serve to protect the fiber ends and otherwise the interior of
the connector parts. This known arrangement is based upon a
terminating axial displacement of the optical fibers in the
connector so that these are brought into mutual abutment for
the finished interconnection. Thus, the arrangement does not
make possible any cleaning of the optical interfaces on the
fiber ends in connection with the coupling operation.
It is a purpose of this invention to provide an improved
fiber optic connector which to a substantial degree reduces
the problems discussed above. Thus, on the background of the
state of the art the invention takes as a starting point a
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fiber optic connector comprising two mating eonneetor parts
eaeh being provided with a cover for pro-tection in the discon-
nected eondition of the connector, the mating movement of the
connector parts for eoupling these together causing movement
of the covers so that there may be formed a con-tinuous light
path -through the connector. What is novel and specific in the
connector according -to the invention in -the firs-t place eon-
sists therein that the optical light path is permanently extended
to an interfaee on eaeh eonneetor part, -that the interfaces of
the connector par~s are adapted to slide against each other
during the mating movement and that eaeh eover has a wiper ele-
ment adapted to clean the ad]aeen-t interfaee during movement
of the cover.
With this solution the eonneetor will be self-cleaning
at the same time as it is proteeted against contamination when
disconnected. Thus, when the connector is disconnected or de-
taehed, a protective eover is loeated in front of the trans-
mission path where it is penetrating an interfaee in eaeh eon-
neetor part. When the eonneetor is eonneeted, the eovers on
both conneetor parts are displaeed and this movement eauses a
wiping aetion on the interface of the fiber end or lens eon-
eerned, whieh is incorporated in the optieal light or signal
path in the eonneetor. The eovers are preferably spring biassed
and therefore are automatically brought into the proper plaee
when the eonneetor is diseonneeted. It is also possible,
however, to let the design be based upon a manual retraetion
of the eovers when the eonneetor is diseonneeted. Moreover, the
eovers may be provided with return means whieh make it possible
to eheek the fibers when the eonneetor is diseonneeted.
In the strueture deseribed here the light path is running
in sueh a way in the conneetor that the direetion of movement
of eaeh eover eoineides with the direetion of movement when
mating the eontaet parts. Thus, the direetion of movement is
essen-tially transverse to and preferably normal to the light
path in the region adjaeent the interfaees. In a praetieal
embodimen-t -the light path interfaee lies in a side-wall of the
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connector par-t concerned, running parallel to the mating direc-
-tion or substantially coincident with the longitudinal direction
of the connector and thereby with the main direction of -the
fiber op-tic cables or wires on which the connector parts are
mounted.
As a wiper elemen-t -there is preferably used a rubber
profile or the like. This may be mounted in a suitable recess in
the cover. Instead of rubber as the material of the wiper element,
a suitable type of plastic material or another suitable material
may be used.
A substantial advantage of the solution s-tated here
consists therein that the protective covers are automatically dis-
placed and removed when -the connector parts shall be connected,
and at the same time results in a wiping action which will remove
possible contaminations which might have reached the interfaces
of the light path in the connector parts.
In connection with the solution discussed above there
has also been developed fiber holders cn which one surface consti-
tutes said interface, these fiber holders preferably havi,ng a
certain limited degree of movability.
The invention may be summarized as a fiber optic con-
nector comprising two cooperating connector parts each being
provided wi-th an associated cover for protection in a disconnected
condi-tion of the connector, whereby the mating of the connector
parts for mutual coupling therebetween causes movement of said
covers so that there is established at least one continuous
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optical light path through the connector, wherein: said at least
one opti.cal light path includes a Eirst optica] fiber permanently
extended to a surface on a firs-t one of said connector parts
and a second optical fiber permanently extended to a surface of
a second one of said connector parts; said surfaces on said con-
nector parts are arranged to slide against each other during
movement to couple said connec-tor parts; said covers are arranged
to slide respectively over the surfaces of their associated con-
nector parts during said movement; and each said cover has a
wiper element adapted to clean a tip of the optical fiber whichextends to the surface of the associated connector part when said
cover slides.
The invention will now be described in greater detail
with reference to the accompanyi.ng drawings, in which:
Figure 1 schematically and simplified shows the prin-
ciple of the arrangement according to the invention, seen in
longitudinal section,
Figure 2 shows with a similar simplification and in
longitudinal section, an arrangement with lenses for collimating/-
focusing of the light signal,
Figures 3a-d show the arrangement of Figure 2 partly
in longitudinal section and partly in cross-section, with the
connector parts disconnected from each other,
Figure 4 shows an embodiment including mi:rrors or
prisms,
Figures 5 and 6 show two modifications of the arrange-
-3b-
ment of Figure 2,
Figures 7a and 7b schematically and simplified show a
fiber holder seen from the interface and in cross-section,
respectively,
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Figure 8 shows a somewha-t simplified cross-section of
an arrangement with fiber holders as shown in principle on
Figures 7a and 7b~ in a mated position,
Figure ~ shows the arrangement of Yigure 8 in longitudinal
section,
Figures 1Oa and 1Ob show one connector part (the female
part) in the arrangement of Figures 8 and 9, disconnected and
in longitudinal, respec-tively cross-section, also showing some
~urther details,
Figures 11a and 11b show in longitudinal and cross-sec-
tion, respectively, the other connector part (the male part~
in the arrangement of Figures 8 and 9, in disconnected position.
In Figure 1 there are shown two connector parts 2 and 3 oE
which ~he former may be regarded as a male connector and the
latter a female connector. The connec-tor parts are shown in
their connected position, the mating movement having taken
place in a horizontal direction in the figure, for example by
displacement of the female connector 2 from the right towards
the left of the figure. In both connector parts there are shown
two through-going optical fibers 1a and 1b considered to be
extended out of the female connector 3 towards the ieft into
an associated cable or wire. From the male connector 2 the
fibers are considered to be extended out to the right, for
example to a fiber optic cable connected -to the male connector.
During a coupling operation the upper surface or side-
wall on the end portion of connec-tor part 2 slides on a corres-
ponding lower surface (side-wall) on the end por-tion of connec-
tor part 3 until the fiber ends are positioned directly opposite
each other in points 1Oa and 10b. Accordingly, in this embo-
diment the fibers 1a and 1b are deflected substantially at a
right angle from their general direction towards their respec-
tive interfaces being in engagement with each other in points
10a and 1Ob.
As known per se connector parts 2 and 3 may be made of
metal and designed with an inner cavity filled with a suitable
liquid which surrounds the optical fibers 1a and 1b. It is
obvious that such a connector may be intended for one, two or
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a higher number of optical fibers.
Further, Figure 1 shows a protective cover 4 for the male
connec-tor part 2 and a protective cover 5 for the female connec--
tor part 3. I'hus, in the position shown in Figure 1, the cover
4 is retrac-ted on the male connec-tor 2 in a right-hand direc-
tion by -the ac-tion of the end of the female connector 3 in
order that the flber ends may be exposed on the surface of the
male connector 2. In disconnec-ted position -the cover 4 is
adapted -to enclose the outer or le~t-hand end of the male
connector 2 as shown in this figure, so -tha-t the fiber ends are
covered and protected. This retraction of cover 4 takes place
automatically by means of a helical spring which is not shown
in the figure.
In a manner similar to cover 4 also cover 5 is displace-
able under the action of a compressive spring which seeks to
force the cover 5 to the right in the figures. However, ln the
mated condition shown the cover 5 is pushed back from the end
portion of the female connector 3 by means of the end of the
male connector 2.
An essential feature of the arrangement shown consists
therein that the covers 4 and 5 are provided with a rubber pro-
file element 6a and 6b, respectively, which constitutes a wiper
element adapted to clean the contact surfaces when -the covers
are moved. The location of the rubber elements on the covers
will also contribute to the formation of a tight closure over
the ends of the connector parts and in particular the contac-t
portions thereof in their disconnected condition.
The protective covers are made with dimensions and a design
conforming to the respective cooperating connector parts, and
during mating in order to establish contact there will be a
natural movement which provides for the desired wiping and
cleaning. Positioning of the interfaces or the ends of the
optical fibers is obtained by having the connector parts accu-
rately machined to fit into each other with the proper tolerances
so as to obtain low losses.
Figure 2 illustrates a similar arrangement as the one in
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Figure 1, but having lenses inserted for collimating, respec-
tively focusing the light signal. Thus, for the optical fiber
11a in Figure 2 -there is mounted a lens consisting of two
halves 17a~17b each mounted to its connector part, i.e.
male connector 12 and female connec-tor 13, respectively. The
surfaces to be cleaned in the light path are in -this embodimen-t
the side-wall facing downwards on lens member 17b and the side-
wall facing upwards on lens member 17a. A rubber element 16a
on cover 14 therefore serves to clean the interface on lens
member 17a whereas a rubber element 16b on cover 15 serves to
clean the interface on lens member 17b.
The lenses employed rnay for example be of the type having
a graded index of refraction and be ng sold by Nippon Sheet
Glass ~ompany under the designation~SELFOC. However, such a
connector may also be designed for other types of lenses. The
advantage with a design with lenses is -that the positioning
requirements in the longitudinal and the transverse direction
are less severe.
For a more detailed explanation of the embodiment of Figure
2, Figures 3a, 3b, 3c and 3d show the two connector parts in dis-
connected condition. Thus, Figure 3a shows the female connec-
tor 13 with the protective cover 15 in position so as to cover
the interfaces on the pair of lenses. The same also is apparent
from the cross-section in Figure 3b. In a corresponding manner
Figure 3c shows a cross-section and Figure 3d a longitudinal
section through the male connector 12 with protective cover
14 in closed position over the lens surfaces.
Figure 4 shows an embodiment of the arrangement based upon
mirrors or prisms, inter alia for the purpose of ma~ing possible
a higher number of connections or optical fibers in the connec-
tor. The arrangement of Figure 4 may either be circular or rec-
tangular, possibly a square arrangement in which a male connec-
tor 22 is adapted to be moved centrally into a female connec-
tor 23. The cover 24 of the male connector is provided with a
rubber element 26a whereas -the cover 25 of the female connector
is provided with a rubber element 26b. There are shown two
signal or light paths through the connector, of which the lower
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path comprises optical fibers 21b, a lens 27b in the male
connector 22 and ano~her lens 27bb in the female connector
23, associated prisms 28b an~ 28bb respectively, as well as
an optically transparent material 29b and 29bb respectively,
filling the space between both prisms. Thus, in this embodi-
ment it is the inter-engaging interfaces or side-walls of the
filling 29b and 29bb, respectively, which is subjected to the
self-cleaning effect by means of the rubber element 26b and
26a, respectively, when the connector part is disconnected and
connected, respec-tively.
The retraction of covers 24 and 25 when disconnecting
the connector in Figure 4, takes place automatically by means
of helical spring 102, 101 respectively, which exert a pushing
force on the respective covers. Spring 101 which seeks to push
cover 25 to the right in the figure is therefore in engagement
(not shown~ against a part of the female connector 23 to the
left outside the figure. In a corresponding manner spring 102
pushes in the opposite direction on cover 24.
As in the embodiments shown in Figures 1, 2 and 3 the
interfaces in the embodiment of Figure 4 may be regarded as
lying in a side-wall of the respective connector parts 22 and
23. These side-walls run parallel to the direction of movement
of the connector parts when mated, and during disconnection
thereof, respectively. In the examples shown this direction
of movement is substantially the same direction as the main
direction or longitudinal direction of the connector itself
and the cables or wires connected thereto.
Figures 5 and 6 illustrate particular modifications of the
arrangement of Figure 2, with a design of the cover which makes
it possible to measure the light transmission in the adjoining
fiber cable when the connector is disconnected. In Figure
5 there is shown a connector part 43 with optical fibers 41a
and 41b with associated lens parts 47a and 47b, respectively.
A cover 45 in similarity with the embodiment of Figure 2
has a rubber element 46 for wiping the interfaces on lenses
47a and 47b. Besides, on cover 45 there is mounted a prism
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49 which wi-th its reflecting surfaces provides for the coupliny
of the optical fiber 41a directly hack to the op~ical fiber
41b so that the op-tical signal is sent back through the cable
being connected to connector part 43.
In -the embodiment of Figure 6 there is shown a connec-tor
part 53 with optical fibers 51a and 51b with associated lens
members 57a and 57b. In this case cover 55 is provided with
two lens members 57a and 57bb adapted to cooperate with the
two first mentioned ler.s members and besides being mutually
interconnected through an optical fiber loop 59 so that also
here there is obtained a retransmission of the optical signal
from fiber 51a to fiber 51b when the cover 55 is in its protec-
tive position.
The embodiments of Figures 5 and 7 involve a particularly
advantageous possibility for checkinq the cable and terminal
equipment when there is employed a connector according to -the
present invention. Such a checking or monitoring possibility
is not previously known from the literature and is particularly
incomplicated with the proposed location of the ligh-t path in
the side-walls of the connector. In consequence of the above
described cleaning effect obtained by means of rubber elements
on the covers, for example rubber elements 46 and 56 on covers
45 and 55, respectively, as shown in Figure 5 and Figure 6,
respectively, there exist very good conditions for useful and
correct measurementSfor checking associated fiber cables and
terminal equipment in connection with the employment of fiber
optic connectors according to the invention.
On the remaining E'igures 7-11 there is shown a structure
based upon the same principle as above, but with certain im-
portant details further developed. This in particular applies
to a specific fiber holder on each connector part, whereby a
surface of the fiber holder constitutes said interface, which
fiber holder serves to mount the optical fiber or fibers in-
corporated in the arrangement, possibly a lens or lenses and a
protective glass or windows.
Thus, these fiber holders are located in the side-wall
of -the connector parts. According to what has been described
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above also these fiber holders are protected each by a separate
cover in disconllected condition, whereas during mu-tual coupliny
of the connector parts they are exposed and form a continuous
light path throuyh the connector. According to the same prin-
ciple as above the covers and/or the connector parts may also
here be provided with wiper elements which clean the fiber
holders when coupling is effected.
Moreover, -the fiber holders may be provided with lenses
which collimate and focus the light from and to the fiber
ends. Such lenses reduce the requirement as to positioning
accuracy and makes it possible to employ a protective glass.
Another important fea-ture of the embodiment described here
has to do with the positioning of the connector parts or more
specifically of the fiber holders in relation to each other.
This is obtained by means of guide pins which for example from
the fiber holder of the female connector are automatically pres-
sed down into holes in the male connector fiber holder when the
same has an approximately correct position. One or both fiber
holders, for example the fiber holder in the female connector,
is suspended in a flexible or movable manner, for example under
spring bias, and thereby makes possible an exact positioning
with respect to the cooperating fiber holder.
Disconnection may take place upon having lifted the guide
pins out of the corresponding holes by means of a lifting
mechanism. The lifting mechanism is activated with a release
arm which is incorporated in one of the connector parts, for
example in the male part.
While Figures 7a and 7b illustrate a fiber holder separa-
tely, the remaining Figures 8 - 11 are related to the same
structure seen in various stages of mating and disconnecting,
in longitudinal and cross-sections, respectively, as stated
more closely in the list of figures above.
In Figures 8 and 9 there are shown two connector parts
210 and 211 of which the former may be regarded as a female
connector and the latter a male connector. The connector
parts are shown as mutually coupled, the mating movement
having taken place in a hori~ontal direction in Figure 9,
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for example by having displaced the male connector 211 from
-the right towards the left in the figure. In Figure 8 the same
connector parts are shown in cross-section. Thus, Figure 8
shows a continuous light path through a fiber holder 201a,
fibers 206a, lenses 204a, protective glass 203a and an inter-
face 202. Moreover, in the male connector there are in a similar
way a protective glass 203b, lenses 204b and optical fibers
206b in a fiber holder 201b.
The op-tical fibers illustrated con-tinue into cables 100
and 110, respectively, which may be terminated in -the connector
parts as shown in Figure 1Ob with respect to the female connec-
tor and in Figure 11a with respect to the male connector.
During coupling the outward surface 202 on the male fiber
holder 201b slides against the corresponding surface on the
female fiber holder 201a. It is obvious that these surfaces
correspond to the previously mentioned interfaces or side-
walls. The movement goes on until the guide pins 207 are
pressed into corresponding holes 105 (Figure 7b) in the fiber
holder of the male connector.
Figures 7a and 7b schematically show a fiber holder 101
with associated holes 105 for a guide pin, holes 104 for lenses
and fibers and a recess 103 for protective glass. The fiber
holders may be made for the desired number of fibers by
changing the number of lenses 104. As apparent from Figure 7b
this embodiment is intended for six fibers.
An exact positioning between the fiber holders in both
connector parts (Figures 8 and 9) may be obtained because
the female fiber holder 201a is resiliently suspended and has
a spring bias. Such springs 214 and 215 are shown in Figures
1Oa and 1Ob. Similarily the guide pins 207 are forced down
by separate springs 216 and 217. The described resiliency or
movabili'cy of one or possibly both fiber holders, which may
also be obtained in other ways, reduces the requirement as to
tolerances and accuracy of the remaining portions of the
connector.
When the guide pins are depressed into the male connector
the connec-tor parts are latched with respect to each other.
1 1
Disconnection takes place by operating a lifting mechanism
208 which lifts the guide pins 207 out of the holes in the
male fiber holder 201b and the connec-tor parts may be with-
drawn from each other. The lifting mechanism is elevated by
means of a release arm 212.
Similar to what is explained with reference to Figures
1 - 6, the structure of Fiyures 8 - 11 is designed so that -the
protec-tive covers 209a and 209b, respectively, for the female
connec-tor and the male connector, respectively, is automatically
put in-to position in front of their respective fiber ho]ders
201a, 201b when the connector is disconnected. Automa-tic re-
turn of the covers may be obtained for example by means of
springs 213. The au~omatic operation of the covers is possible
because the fiber holders are located in the side-walls of the
la-teral connector and because of the simple design of the
connector otherwise.
The desi~ln and ~oupling principle of the fiber connector
also makes it possible in the embodiments of Figures 8 - 11
to provide the covers 209a, 209b and the connector parts 210,
211 with wiper elements 219a, 219b and 21~a, 218b, respecti-
vely, for cleaning the interface 202 of the fiber holders
including the protective glasses 203a, 203b. The wiper ele-
ments reduce the probability of losses due to contaminations.
The elements may be located in suitable grooves and may be
made of leather, rubber or a plastic material. The movement
of the connector parts when brought into engagement with each
other will cause the wiper elements to be moved over the de-
scribed interfaces on the male connector and the female connec-
tor, respectively.
The protective cover 209a (Figure 1Oa~ for the female
connector may be provided with return means 220 in front of
the protective window 203a in order that the light transmission
in the fibers may be checked when the connector is disconnected.
The return means 220 may be a prism or a material having a de-
fuse reflec-tion. The protective cover 209b for the male con-
nector may also have similar means in order to obtain a possi-
bility of monitoring the light transmission in the fibers ex-
tended to the male connector, when in a disconnected condi-
12
tion.
The number of connections or optical fibers changes inthe various embodiments shown in the figures of drawings.
It is obvious that in principle a:Ll the embodiments being
shown more or less schematically, may be modiEied so as to
make possible the coupling of one or more con-tinuous light
paths~therethrough.
