U.S. patent application number 13/634507 was filed with the patent office on 2013-10-17 for integrated illuminator.
This patent application is currently assigned to UNIVERSITY COURT OF THE UNIVERSITY OF ST ANDREWS. The applicant listed for this patent is Malcolm Harry Dunn, Graham M. Miller, Donald Walker. Invention is credited to Malcolm Harry Dunn, Graham M. Miller, Donald Walker.
Application Number | 20130272720 13/634507 |
Document ID | / |
Family ID | 44070030 |
Filed Date | 2013-10-17 |
United States Patent
Application |
20130272720 |
Kind Code |
A9 |
Dunn; Malcolm Harry ; et
al. |
October 17, 2013 |
INTEGRATED ILLUMINATOR
Abstract
An optical device comprising a sealed/closed housing; a light
source and/or a detector within the housing; a window through the
housing that is transparent to light transmitted from the light
source or to the detector and a fixing for fixing an optical fiber
or bundle of such fibers into a coupling position adjacent to the
window to allow light to pass between the housing and the fiber or
fiber bundle, wherein the fixing is adapted to allow connection
and/or disconnection of the fiber or fiber bundle without opening
or breaking a seal of the sealed housing.
Inventors: |
Dunn; Malcolm Harry; (Fife,
GB) ; Miller; Graham M.; (Dundee, GB) ;
Walker; Donald; (Fife, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dunn; Malcolm Harry
Miller; Graham M.
Walker; Donald |
Fife
Dundee
Fife |
|
GB
GB
GB |
|
|
Assignee: |
UNIVERSITY COURT OF THE UNIVERSITY
OF ST ANDREWS
St Andrews
GB
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20130064556 A1 |
March 14, 2013 |
|
|
Family ID: |
44070030 |
Appl. No.: |
13/634507 |
Filed: |
March 30, 2011 |
PCT Filed: |
March 30, 2011 |
PCT NO: |
PCT/GB2011/000481 PCKC 00 |
371 Date: |
November 26, 2012 |
Current U.S.
Class: |
398/182; 362/553;
362/554; 362/556; 398/202 |
Current CPC
Class: |
G02B 6/3897 20130101;
G02B 6/4248 20130101; G02B 6/403 20130101; G02B 6/0006 20130101;
G02B 6/3891 20130101; G02B 6/0008 20130101; G02B 6/3816
20130101 |
Class at
Publication: |
398/182; 362/554;
362/556; 362/553; 398/202 |
International
Class: |
F21V 8/00 20060101
F21V008/00; H04B 10/04 20060101 H04B010/04; H04B 10/06 20060101
H04B010/06; G02B 6/04 20060101 G02B006/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2010 |
GB |
1005485.6 |
Feb 4, 2011 |
GB |
1101927.0 |
Claims
1. An optical device comprising: a housing wherein the housing is
sealed; a light source or a detector within the housing; a window
through the housing that is transparent to light transmitted from
the light source or to the detector; and a fixing for fixing an
optical fiber or bundle of such fibers into a coupling position
adjacent to the window to allow light to pass between the housing
and the fiber or fiber bundle, wherein the fixing is adapted to
allow connection and disconnection of the fiber or fiber bundle
without opening or breaking a seal of the housing.
2. The optical device as claimed in claim 1 wherein the fixing
holds the optical fiber or bundle of fibers in butt coupled contact
with an external surface of the window.
3. The optical device as claimed in claim 2 wherein the fixing is
adapted to compress the fiber or fiber bundle end against the
window.
4. The optical device as claimed in claim 1 wherein the fixing is
adapted to mate with a fixing element on the fiber or fiber
bundle.
5. The optical device as claimed in claim 4 wherein the fixing
comprises a male part and a female part, one being on the housing
and the other being on the fiber or fiber bundle.
6. The optical device as claimed in claim 5 wherein the fixing
comprises a bayonet connector.
7. The optical device as claimed in claim 1 wherein a heat sink is
provided within the housing.
8. The optical device as claimed in claim 1 wherein a non-imaging
light concentrator is provided for directing light between the
light source or detector and the window.
9. The optical device as claimed in claim 1 wherein the light
source and the window are integrated.
10. The optical device as claimed in claim 9 wherein the light
source, the window, and the heat sink are integrated.
11. The optical device as claimed in claim 9 wherein the light
source, the window, and the non-imaging light concentrator are
integrated.
12. The optical device as claimed in claim 11 wherein the
integrated components form a composite structure that has a depth
of less than 15 mm.
13. The optical device as claimed in claim 11 wherein the housing
has a lid and a body portion and the integrated parts are located
in the lid.
14. The optical device as claimed in claim 1 wherein the housing is
waterproof and/or fireproof and/or explosion proof.
15. The optical device as claimed in claim 1 wherein the housing is
pressurized for operation at depths.
16. The optical device as claimed in claim 1 wherein the device is
adapted for use with one or more side emitting optical fibers.
17. The optical device as claimed in claim 16 wherein the side
emitting optical fibers are formed into a bundle contained within a
sleeve.
18. The optical device as claimed in claim 16 wherein the side
emitting fibers are braided into a ribbon.
19. The optical device as claimed in claim 17 wherein the fiber
bundle or ribbon is integrated into material or a garment, such as
wearable clothing.
20. The optical device as claimed in claim 1 wherein the fixing
element is releasable, thereby to allow the fiber or fiber bundle
or fiber ribbon to be released.
21. The optical device as claimed in claim 1 wherein the light
source comprises at least one of: a laser; an LED; a laser diode;
or a fiber laser.
22. The optical device as claimed in claim 1 wherein a power source
for powering the light source is provided in the housing.
23. The optical device as claimed in claim 22 wherein the power
source comprises a battery.
24. The optical device as claimed in claim 1 wherein an external
connection is provided through the housing to allow connection to
an external power source.
25. The optical device as claimed in claim 1 further comprising an
umbilical.
26. The optical device as claimed in claim 1 wherein light
transmitted or received includes one or more communication signals
or messages.
27. The optical device as claimed in claim 26 comprising means for
modulating light to include one or more communications signals or
messages.
28. The optical device as claimed in claim 26 comprising means for
demodulating signal or message carrying light to determine one or
more communications signals or messages.
Description
FIELD OF THE INVENTION
[0001] The present invention is concerned with an optical light
source or box for supplying light to a distributed illumination
system based on side emitting optical fiber or fiber bundles. The
source is adapted for use under adverse and challenging
environmental conditions. The invention also relates to an
integrated illuminator and in particular an integrated fiber based
illuminator for use for illumination and/or communications.
BACKGROUND OF THE INVENTION
[0002] Side emitting optical fibers or fiber bundles that are
illuminated by primary optical sources placed only at the ends of
the fibers are recognized as practical and convenient methods for
distributed illumination. They provide inherently safe illumination
that is continuous and flexible, since the illumination is
distributed along the full length of the fibers or fiber bundles.
These sources require no electrical power to be provided within the
structure of the fiber or fiber bundle itself, since the primary
optical sources that do require electrical supply are located only
at the end or ends of the side emitting fibers or fiber
bundles.
[0003] Side emitting fibers or fiber bundles can provide high
intensity light at peak eye response, as well as light of other
colors as required. They are particularly appropriate for use in
hazardous environments, for example in chemical or oil refining
plants, mines, wellheads, and oil-rig platforms, where illumination
methodologies involving the supply of electrical power within the
hazardous environments can lead to risk of explosions. They also
lend themselves to use in underwater environments, for example,
subsea and any inland water including lakes, rivers, lochs,
harbors, docks, canals and all other types of waterways, including
in aqua-culture, as well as in many other environmentally
challenging situations. In addition, they are ideal for providing
egress/guide-path lighting and safety lighting, for example for
illuminating clear paths to exits. This results from the
distributed and continuous nature of the source along the length of
the fiber or fiber bundle. Furthermore, such sources can also serve
the dual purpose of illumination and communication, where
information is dispersed through appropriate modulation of the
emitted light.
[0004] Side emitting fibers or fiber bundles are used with optical
sources, which generally are associated with electrical/electronic
components. Using such devices in hazardous/challenging
environments can be problematic, as the environment in which the
electrical/electronic/optical components forming the primary
optical source are located has to be isolated from the external
environment to which the side emitting fiber or fiber bundle is
itself subject. Furthermore, the sealing integrity between the
fiber and the electrical environments has to be sustained during
installation, usage, servicing and replacement. In practice,
locating and retaining the fiber relative to the primary light
source can be difficult. Also, there can be problems with
optimizing the coupling of radiation from the primary light source
into the fiber/fiber bundle, and isolating the primary light
source, including protection from dangerous environments. Efficient
management of heat removal from the primary light source is a
further challenge.
SUMMARY OF THE INVENTION
[0005] According to one aspect of the invention, there is provided
an optical device comprising a housing; a light source and/or a
detector within the housing; a window through the housing that is
transparent to light transmitted from the light source or to the
detector and a fixing for fixing an optical fiber or bundle of such
fibers into a coupling position adjacent the window to allow light
to pass between the housing and the fiber or fiber bundle. The
fixing is such that it allows connection and disconnection of the
fiber or fiber bundle without breaking seals to the housing or
light box.
[0006] Light generated within the housing is transmitted through an
optical interface directly into the fiber(s). The use of an
external fixing for securing the fiber or fiber bundle in place
means that the light-box can be sealed for coupling and uncoupling
to the optical fiber or fiber bundle. This means that the integrity
of any optical, electronic or other components within the housing
can be maintained.
[0007] The fixing may hold the optical fiber or bundle of fibers in
butt coupled contact with an external surface of the window. The
fixing may be adapted to compress the fiber end against the window.
The fixing may be adapted to mate with a fixing element on the
fiber or fiber bundle. The fixing may comprise a male part and a
female part, one being on the housing and the other being on the
fiber or fiber bundle. The fixing may comprise a bayonet
connector.
[0008] Within the housing, a heat sink may be provided. Within the
housing a non-imaging light concentrator may be provided for
directing light from the light source to the fiber and/or for the
purpose of optimally coupling the light into the fiber.
Alternatively, the non-imaging concentrator may be employed for
directing light from the fiber to the detector and/or for the
purpose of optimally coupling the light into the detector.
[0009] The light source and the window may be integrated. Where a
heat sink and a nonimaging light concentrator are provided, the
light source, the window and the heat sink and/or the non-imaging
light concentrator may be integrated. The integrated components may
form a composite structure that has a depth of less than 15 mm,
preferably 13 mm or less. The housing may have a lid and a body
portion and the integrated parts may be located in the lid.
[0010] The housing may be waterproof and/or fireproof and/or
explosion proof (Ex) and/or pressurized for operation at
depths.
[0011] The device may be adapted for use with one or more side
emitting optical fibers. Where a plurality of side emitting optical
fibers is used, these may be bundled together, typically twisted
together, and encased in a transparent plastic sheath.
Alternatively, the individual fibers may be braided into a fiber
ribbon. The ribbon may have a flat or circular cross-section.
[0012] The light coupled into the fiber may be shaped so that it
substantially fills the fiber rope. The light coupled into the
fiber may have a substantially uniform power distribution.
[0013] According to another aspect of the invention, there is
provided a composite/integrated optical device comprising a light
source; a window for transmitting light from the source; and a heat
sink. The device may also have an integral light concentrator, for
example a non-imaging light concentrator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Various aspects of the present invention will now be
described with reference to the accompanying drawings, of
which:
[0015] FIG. 1 shows a perspective view of an integrated
illuminator;
[0016] FIG. 2 shows a side and a sectional view of the integrated
illuminator of FIG. 1;
[0017] FIG. 3 shows a section through a top portion of the
integrated illuminator of FIG. 2;
[0018] FIG. 4 shows an expanded view of a composite structure used
in the illuminator of FIG. 3;
[0019] FIG. 5 shows an expanded view of a locking arrangement used
in the Illuminator of FIG. 3;
[0020] FIG. 6 is a schematic representation of a light rope
umbilical system;
[0021] FIG. 7 is the view of the fiber bundle as incorporated
within the umbilical;
[0022] FIG. 8 is a side view of an individual fiber of a light rope
for use in the system of FIG. 6;
[0023] FIG. 9 is a view of the fiber bundle showing a helical
pitch;
[0024] FIG. 10 is an end view of a fiber bundle showing the
arrangement of individual fibers and sleeving;
[0025] FIG. 11 shows the illuminator at the diver end and for a
fiber bundle umbilical illuminated from both ends;
[0026] FIG. 12 shows the umbilical in use in various operational
environments;
[0027] FIG. 13 shows a fiber ferrule clamp arrangement, and
[0028] FIG. 14 shows a controlled compression system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIGS. 1 to 3 show a fiber based illuminator that has a
sealed light source unit and a fiber that can be releasably coupled
to the light source unit without having to open or break any seal,
thereby maintaining the sealing integrity of the light source unit.
The sealed light source unit has a housing 2, which has a main body
3 and a lid 4. The lid 4 is threaded to the body 3 and sealed using
two seals: a main seal 14 and a secondary seal 15. The body 3 and
lid 4 may be made of any suitable material, for example, aluminum
alloy.
[0030] Within the body 3 is a primary light source 7. This is
mounted on a heat-sink interface 9, see FIG. 3. At the output of
the primary light source 7 is a conical non-imaging light
concentrator 8. This directs light through an optical window 5 and
provides an integrated support for the window. The non-imaging
light concentrator may be adapted to ensure that light coupled into
the fiber or fiber bundle substantially fills the fiber or fiber
bundle and/or may be adapted to optimize the light power coupled
into the fiber or fiber bundle. The light may have a substantially
uniform power distribution.
[0031] The optical window 5 is transmissive to light from the
source 7 and is positioned adjacent an opening through the lid 4,
so that light can pass from the interior of the sealed housing to
the exterior. On an upper surface of the optical window 5, a seal 6
is provided. This is sized to match the opening through the lid 4
and to form a seal to ensure that interior of the housing is
isolated.
[0032] The primary light source 7, the integrated heat-sink
interface 9, the conical non-imaging light concentrator 8, and the
optical window 5 together form a composite, integrated structure,
as shown in FIG. 4. The depth of this structure may be 13 mm or
less. Typically, the composite structure is formed as a separate
unit for insertion into the lid 4, thereby simplifying manufacture.
Doing this means the unit can be readily adapted for different
environments without needing a product re-design every time. This
is because the window of the structure can be varied depending on
the strength needed for a particular environment.
[0033] The composite structure integrates the functionalities of:
matching the primary light source with the characteristics of the
fiber through the conical non-imaging light concentrator; retaining
and locating the window; securely positioning the primary light
source; providing when assembled an efficient heat-sink, and
sealing the window thereby affording protection of the light source
and other components from the external environment.
[0034] To power the primary light source 7, a constant current
driver 20 and a battery 19 are provided. In addition, an electrical
connector (male/female) 18 is sealed to the canister lid 4 using
seal 16. The electrical connector 18 can be any suitable electrical
wet connect. These are well known and so will not be described in
detail. Power can be provided by the battery or through the
electrical cable 17.
[0035] Although not shown, other electronics could be provided
within the sealed environment of the housing, for example, a
control system for controlling light emission. Also, means may be
provided for sending and/or receiving at least one data carrying
optical signal along the light rope. In this case, the fiber or
fiber bundle assumes a dual functionality in providing both
illumination and communications. The means for sending at least one
data carrying optical signal along the fiber may modulate light
from the light source 7, the modulation representing the
data-carrying signal and/or by injecting data carrying light from
another source (not shown) into the fiber. To implement and/or
control communications a processor may be provided inside the
housing.
[0036] To allow an optical fiber or fiber bundle to be connected to
the light source unit, a quick release positive fiber locking
mechanism is provided, with one part on the lid 4 and the other on
the end of the fiber.
[0037] To position the locking mechanism, the lid 4 has a locator
element that has a cylindrical threaded portion that is sized to
match a thread in the opening through the lid 4, so it can be
threaded into position. The locator element widens out to define a
further cylindrical portion, which provides support for a male
connector part 12 of the quick release locking mechanism. The male
connector 12 is fixed to the locator element and has a bayonet
mount connection for mating with a corresponding female connector
element 11, which extends round the optical fiber. The male and
female connector elements interact to position the fiber 1 securely
on the lid. The height of the locator element, the size of the
connector parts and the position of the end of the fiber(s) are
selected so that when the male and female parts are connected the
ends of the fiber are in contact with the window 5 and maintain
good fiber/window interface. In some embodiments, the arrangement
is such that the end of the fiber or fiber bundle is in direct
contact with the window.
[0038] Using a simple bayonet fitting ensures quick, accurate and
repeatable high performance optical connection of the fiber to the
light source unit, whilst maintaining the sealed environment within
the unit.
[0039] The light source unit is provided as a fully sealed/closed
unit, which, depending on the application may be waterproof and/or
fireproof and/or explosion proof (Ex). To connect a fiber to the
unit, a user merely has to use the simple press mechanism of the
bayonet connector. There is no need to open or break the seal of
the housing to make the connection. Instead, the connection is made
entirely externally. The physical relationship between the
integrated light source and window, and the connecter ensures
accurate alignment of the fiber or fiber bundle with the output of
the light source. Because of the sealed nature of the unit, the
fiber can be connected above or below water.
[0040] An illumination unit in accordance with the invention has
been made and pressure tested to a depth of 1000 m. In these tests,
the unit was made of marine grade aluminum alloy.
[0041] The illuminator of the present invention can be used in
numerous applications. For example in hazardous environments;
underwater including ROV and derivatives; umbilical (all
environments); distributed communications; safety; escape/guide
path; marine; offshore including helipads; petrochemical; mines;
tunnels; wind generation facilities both on and off shore; tidal
and wave generation, and aqua-farming. Also, it can be used with
end and/or side emitting fiber and or fiber bundles for the purpose
of illumination, communication and dual functionality of
illumination and communication.
[0042] As a specific example the illuminator of the invention can
be used in an underwater umbilical system. FIGS. 6 and 7 illustrate
an umbilical. This has various conventional umbilical parts 23
wound together, such as a gas hose and a power line, as best seen
in FIG. 7. In addition, the umbilical includes a fiber bundle 25
that has multiple side-emitting optical fibers 27. The side
emitting optical fibers 27 provide a distributed source of light
that allows the umbilical to be lit along its length, thereby
providing a guide-path as well as general illumination of the
subsea environment within which the diver or divers are working
[0043] A light emitting diode (LED) 29 powered by a driver 31 is
provided for illuminating the rope. The LED 29 is enclosed within a
compact watertight enclosure or light-box 33 which is located
adjacent an umbilical interconnect-interface 35. Radiation from the
LED 29 passes through an optical coupling 36 arrangement, which
transforms the spatial characteristics of the primary radiation
from the LED 29 to optimize its coupling into the fiber-bundle 25.
The radiation then passes through a window 37, which is mounted on
a water-tight seal 39 on the side of the watertight compartment 33,
before entering the fiber-bundle 25. The prepared ends of the
fibers making up the bundle 25 are held in compression by element
41 so as to be in contact with and butt-coupled to the outer
surface of the window 37. The optical arrangement described is such
that this location of the fiber-end also optimizes the coupling of
the radiation into the fiber.
[0044] Whilst any LED may be used, in a preferred example, the LED
generates light in the green spectral region. Typically, for an
electrical input power to the LED of 12 W, the optical output power
from the LED in the green spectral region is of the order of 400
mW, and the coupling efficiency for this radiation into the fiber
is of the order of 23-28%.
[0045] The fiber bundle may be made up of any number of fibers. In
a preferred example, fourteen individual plastic fibers 43 are used
with a core diameter of 0.74 mm and refractive index of 1.49, and
with an outer cladding of wall thickness 0.06 mm and refractive
index 1.40, see FIG. 8. As a specific example these fibers would
conform to Eska CK30 fiber. The fibers are wound in a tight helical
bundle 45 with a pitch of 10 cm, see FIG. 9. The packing of the
fibers as appears at each end of the bundle is of the form of four
central fibers surrounded by ten other fibers, all encased within
an outer sheath 47 that is transparent to the light that is to be
used, see FIG. 10. The plastic sheaf has a nominal wall thickness
of 0.85 mm, the walls of the sheaf being transparent to the green
radiation. Typically, the fiber bundle is of length 100 m,
compatible with a standard umbilical.
[0046] The fiber-bundle geometry of FIG. 10 typically experiences a
loss of the order of 5%/m due to radiation escaping through the
side walls as required, this being determined both by the tightness
of winding and the compression of the bundle by the outer sleeve.
Both these aspects are controllable for the purposes of
optimization during the manufacturing process. For the
specifications given above satisfactory illumination and brightness
of emission is attained for fiber lengths up to 100 m. The
watertight compartment 33 also contains a back-up battery 49 (3
hours of steady state lighting or six hours on flash) with a built
in charger circuit 51. This circuit contains the flash interface
which is controlled from the surface by the dive supervisor. This
will also allow remote operation in the event on no mains. The
system in normal operation requires 12 W@18V DC.
[0047] In some circumstances, it may be desirable to allow the
injection of light from both ends of the fiber. Another arrangement
is where the fiber is illuminated from both ends, namely from the
surface end of the fiber as described above and also from the
underwater end as attached to the diver. For the latter purpose
FIG. 11 shows a compact watertight pressurized light-box 53
designed to operate at depth of typical dimensions 100 mm.times.50
mm diameter which is attached at the diver end to the fiber and
contains a rechargeable battery 55, LED 57, associated driver
circuit 59, optical coupling arrangement 61, and output coupling
window 63 with facility for butt-coupling the fiber ends as
previously.
[0048] Overall characteristics for the underwater source for use in
the arrangement of FIG. 11 regarding optical power into fiber, etc.
are similar to the surface based illuminator.
[0049] Under normal operating conditions, the system is powered by
the diver's electrical supply emanating from the surface and
provided by the power cable of the umbilical, but with a battery
back-up of one hour. This arrangement significantly increases
illumination levels in the vicinity of the diver(s), and provides
back-up through built-in redundancy in the event of fiber damage or
light source failure. It can also significantly increase umbilical
operational length.
[0050] The light injected into the fiber bundle may be modulated so
as to carry a message or information. The modulation of light may
be such that it can be seen directly by eye, for example in the
case of a general warning message. Alternatively or additionally,
an optical receiver capable of decoding the modulated message may
be provided for subsequent oral, visual or other mode of
presentation to divers or other relevant parties.
[0051] A controller (not shown) may be provided at one or both ends
of the umbilical to cause the light emitted from the fibers to be
altered. For example, the light could be caused to flash on and
off. This could be used by divers in emergency situations to
provide a general warning, for example, highlighting a change in
operational conditions or a specific diver in difficulty, thereby
making colleagues immediately aware of a change state. A lit and
flashing umbilical could speed up rescue operations in identifying
the diver at risk.
[0052] FIG. 12 shows various different operational environments in
which the umbilical could be used. These include between the
surface and a subsea location (surface-air diving application),
FIG. 12(a) or between a diving bell and individual divers
(saturation diving), FIG. 12(b). It may also be used between two or
more subsea locations for example in connection with remote
operating vehicles (ROVs) FIG. 12(c).
[0053] Although FIG. 11 shows a simple compression element, any
suitable external fixing element could be used to releasably secure
the fiber or fiber bundle in place. For example, FIG. 13 shows a
fiber termination arrangement where the fiber bundle with
individual fibers is retained within a compression ferrule 65 that
holds the fibers in a given orientation and with a square end face
for efficient butt coupling to the light source or optical
window.
[0054] FIG. 14 shows another coupling assembly utilizing a
controlled compression system where the fiber is held against the
output coupling window 67 and uses a tapered clamp arrangement 69
that allows uniform compression on the fiber bundle while retaining
the fiber against the window 67. In this case, the optical coupling
window 67 is provided in a tubular recess in the housing that has a
screw thread 71 formed at one end. Mounted against the window 67 is
a tubular part 73 that is shaped to receive the end section of the
fiber bundle, so that light can pass through the window between the
interior of the housing and the ends of the fibers. The external
surface of the end of the tube remote from the window is tapered,
to form an inwardly sloping surface 73. This is shaped to mate with
a fixing element. The fixing element 75 has an externally formed
screw thread 77 matched to the screw thread 79 on the housing and a
tapered surface 81 matched to the taper 73 on the tubular part.
[0055] In use, the fiber bundle can be coupled to the light box by
inserting it into the tubular part until the end of the fiber
bundle makes contact with the window. By applying a screwing action
by means of the fixing element 75 compression is applied to the
tubular part through engagement of the tapered surfaces 73 and 81,
thereby transferring linear compression both through the fiber
bundle and through the tubular part to the window. This ensures
good butt coupling and hence optical interface to the window, while
simultaneously applying radial compression to the fiber bundle
hence retaining the fiber bundle in its position against the
window.
[0056] The coupling arrangement(s) outlined can be utilized in a
variety of applications that require efficient light injection and
or ability to connect/disconnect rapidly without breaking the
sealing arrangement of the light-box device.
[0057] The present invention provides a safe, low-power
light-source that can be readily coupled into a side emitting fiber
rope to provide a continuous, flexible and distributed along the
full length of the umbilical. The source can be used in any
underwater environment for example subsea and any inland waters
including lakes, rivers, lochs, harbors, docks, canals and all
other types of waterways. The source requires no electrical power
within the structure of the umbilical itself and can provide high
intensity light at the peak eye response, as well as light of other
colors if required. It provides a clear return path back to safety
resulting from the distributed and continuous nature of the source
along the length of the umbilical. It provides visual information
between divers as to their relative locations in the subsea
environment, as well as general illumination of the underwater
working environment thereby increasing the visual acuity of
operatives so improving both their safety and their efficiency of
working.
[0058] A skilled person will appreciate that variations of the
disclosed arrangements are possible without departing from the
invention. For example, although the invention is described with
reference to a bundle or ribbon of fibers, a single fiber or a
light pipe may be used. Also, the fiber (bundle, ribbon, single or
otherwise) may be provided as part of a material or a garment. For
example, the fiber may be integrated into a wearable item, such as
an item of clothing, e.g. safety apparel. The wavelength of the
radiation generated by the laser may be shifted in frequency by
some optically non linear technique so as to be suited to the
purpose. Whilst green is a preferred color any spectral color may
be used. Accordingly the above description of the specific
embodiment is made by way of example only and not for the purposes
of limitation. It will be clear to the skilled person that minor
modifications may be made without significant changes to the
operation described.
* * * * *