Note: Descriptions are shown in the official language in which they were submitted.
2 1'575 3
80376-9
ILLUMINATION DEVICES AND METHODS OF FORMING SAME
The present invention relates to light conducting
and light emitting tubes, herein referred to as "light
tubes", and newel optical light films having an embossed
prism pattern to contain and channel the light when formed
into a tube. More particularly, the present invention is
concerned with laminated tube construction and methods of
constructing light tubes to achieve a wide range of
illumination e~ffect;~ including the piping of light from an
accessible, concentrated light source to distal areas and
the release of~ such light in widely variable patterns.
Optical light films (OLFs) can be efficiently
manufactured from polymers in flat, flexible, but~fragile
films and made tc> perform a myriad of illumination
functions. The film can be formed into various tubular and
other partially closed configurations by supporting it
together with supplemental light controlling films or
elements in pr~~formed carrier tubing having light-permeable
characteristics. For example, a sheet of OLF can be formed
into a closed tube by disposing one longitudinal edge of
the OLF adjacent the opposite longitudinal edge.
Alternatively, a sheet of OLF can also be formed into a
partially closed tube, for example having an arched cross-
section, and maintained in such a configuration with a
supporting structure. As used herein, the term "tube" is
meant to include both closed and partially closed
configurations.
In addition to carrying light from a source of
illumination ;such as a high-intensity light bulb to a
remote location, light tubes can also be used for emitting
light over relatively large areas. For this purpose,
various methods have been devised to direct light out of a
light tube over portions of the tube length. One method
involves placing a clear adhesive tape on the outer,
2 17,~ 75 3
- 2 -
grooved side c>f an optical light film. A clear tape placed
in this manner reduces the internal reflectance of the
optical light film in the taped area and essentially
creates a window for "escaping" light. Another method
simply involves removing a section of the optical light
film where ini~ernal reflectance is not desired. Portions
of a tube lac)cing optical light film will permit light to
escape. A third method comprises forming a light tube with
some means for directing the light at the walls of the
optical light film at an angle greater than about 28°. At
such angles oi= incidence, the internal reflectance of the
optical light film is greatly reduced. For example, the 3M
Company of St. Paul, Minnesota, produces a product marketed
under the name "2370" which directs incident light at an
angle of about: 90° too the angle of incidence. If a piece
of "2370" is positioned within a light tube, light moving
generally along the longitudinal axis of the tube will be
directed through the "2370" substantially perpendicular
toward a sidewall and out of the light tube. Another
product, marketed under the name "SCOTCH-CAL EXTRACTOR
FILMT"'", directs light toward and through an opposite
interior wall.
Since optical light film is fragile and sensitive
to dirt and rnoistur.e, it is typically positioned within
protective, outer tubes. Such tubes are generally
transparent and can have a variety of finishes, e.g. clear,
matte, colored or opaque. The ability to insert the
fragile optical light films into a carrier tubing,
typically an extrusion product, is an impediment to the
light tube de~~igner" Moreover, shipping fabricated light
tubes is cost7_y because of their high volume relative to
volume of component displacement and their inherent
vulnerability to damage by breaking and scratching. Thus
the low manuf;~cturing cost of the critical optical film
component is heavily offset by shipping costs. Also lost
is the abilit~~r of t:he designer to achieve at acceptable
CA 02175753 2002-05-28
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cost finished products which feature many of the useful
and underlying lighting functions which the optical light
film is inherently capable of performing.
It would therefore be desirable to provide novel
methods for forming light tubes and light tube products
using the films which are cost effective, optically
efficient and functionally varied.
The present invention comprises improvements in
methods of forming light carriers and the resulting light
carriers comprising optical light film.
The present invention provides a light carrier
comprising:
a flexible sheet of optical light film
comprising a first longitudinal film edge and a second
longitudinal film edge;
a middle flexible sheet comprising a first
longitudinal edge portion and a second longitudinal edge
portion;
an outer flexible sheet comprising a first
longitudinal edge and a second longitudinal edge;
means for maintaining said optical light film
and said sheets in a generally tubular configuration;
said maintaining means comprising a first
connector comprising at least one adhesive portion, said
first connector connected to said optical light film at a
position remote from said first longitudinal edge portion
and to said middle sheet at a position remote from
said first longitudinal edge thereby defining a slot; and
CA 02175753 2002-05-28
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said maintaining means also comprising a second
connector having at least one adhesive portion, said
second connector to said middle sheet at a portion remote
from said first longitudinal edge portion and to said
outer sheet at a position proximate said first
longitudinal edge.
The present invention provides a light carrier
comprising:
a first longitudinal film edge and a second longitudinal
film edge;
a sheet of optical light film;
middle sheet comprising a first longitudinal edge portion
and a second longitudinal edge portion;
an outer sheet comprising a first longitudinal
edge and a second longitudinal edge; and
means for maintaining said optical light film
and said sheets in a generally tubular configuration with
said longitudinal edges of said outer film disposed in
abutting relation.
The present invention also provides a light
carrier comprising:
a sheet of optical light film comprising a first
longitudinal film edge and a second longitudinal film
edge;
a middle sheet comprising a first longitudinal
edge portion and a second longitudinal edge portion;
an outer sheet comprising a first longitudinal
edge and a second longitudinal edge;
CA 02175753 2002-05-28
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means for maintaining said optical light film
and said sheets in a generally tubular configuration with
said longitudinal edges of said outer film disposed in
abutting relation;
said maintaining means comprising a first
connector comprising at least one adhesive portion, said
first connector connected to said optical light film at a
position remote from said first longitudinal edge portion
and to said middle sheet at a position remote from said
first longitudinal edge thereby defining a slot;
a second connector having at least one adhesive
portion, said second connector connected to said middle
sheet at a portion remote from said first longitudinal
edge portion and to said outer sheet at a position
proximate said first longitudinal edge; and
a third connector comprising at least one
adhesive portion, said third connector disposed proximate
said second longitudinal edge for maintaining said second
longitudinal edge in abutting relation with said first
longitudinal edge.
The present invention also provides a light tube
comprising:
a first sheet comprising a first longitudinal
edge portion and a second longitudinal edge portion, said
first sheet having sufficient flexibility to allow said
first longitudinal edge portion to be disposed in a
position proximate said second longitudinal edge portion;
a second sheet comprising a first longitudinal
edge, a second longitudinal edge, and a first contact
region remote from first longitudinal edge;
CA 02175753 2002-05-28
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means for maintaining said first sheet in a tube
configuration comprising a first connector having at least
one adhesive portion, said first connector connected to
said first sheet at a position remote from said first
longitudinal edge portion and to said second sheet at a
position remote from said first longitudinal edge;
a second connector comprising at least one
adhesive portion, wherein said second connector is
connected to at least two separate sections of said second
sheet;
at least one optical light film disposed between
said first sheet and said second sheet; and
at least at least one extractor disposed between
said first sheet and said second sheet.
In a still further aspect, the present invention
provides a light carrier comprising:
at least one light tube comprising at least one
optical light film;
a second element connected to said light tube;
means for connecting said second element to said
light tube, wherein said connecting means comprises a heat
resistant material and at least one axial groove.
In a still further aspect, the present invention
provides a light carrier comprising a plurality of
generally tubular segments, each of said segments
comprising at least one optical light film and at least
one other sheet, wherein a sheet of one segment overlaps a
portion of an adjacent segment.
CA 02175753 2002-05-28
- 3d -
The present invention provides a light carrier
comprising:
a longitudinal axis, an ingress end for
receiving light, said light carrier comprising an optical
light film generally formed into a tube shape and means
for directing light out of said light carrier along at
least a portion of the length of said optical light film;
a flexible sheet disposed around a substantial
portion of said optical light film;
means for altering the direction of light
exiting said light carrier, said light directing means
disposed within said light carrier.
One embodiment of the present invention
comprises an optical light film formed with a generally U-
shaped connector which, along with other elements, forms
slots for securely receiving at least portions of the
longitudinal edges of the optical light film. This
embodiment advantageously permits on-site fabrication of
light tube having substantially total (i.e. 360°) internal
reflectance.
Another embodiment of the present invention
comprises an improved optical light film which
advantageously allows controlled amounts of light to exit
the light tube without the need for supplemental
extractors.
Another embodiment of the present invention
comprises a decorative light fixture comprising a source
of illumination, a light tube comprising OLF which emits
CA 02175753 2002-05-28
- 3e -
light over the length of the tube and is also provided
with an emitter for changing the direction of light
exiting the distal end of the light tube.
A still further embodiment of the present
invention comprises a decorative illumination device
~ 17~7~ 3
- 4 -
comprising a light tube disposed substantially
concentricall~r within an outer protective tube.
A j=urthe:r aspect of the present invention
comprises a novel, heat resistant connector which provides
a durable connection between light tubes or portions of
light tubes, for ex<~mple between a optical light film tube
and a bulb housing.
Another aspect of the present invention comprises
a light tube comprising a tapering, optical light film
tube. As explained in greater detail below, a
substantially continuous illumination may be obtained over
the length of a 7_ight tube by providing a carefully
measured conv~erginc~ taper to the light tube in the
direction extending away from the source of illumination.
Another dLecorative embodiment of the present
invention comprise; two sheets of optical light film
positioned with the grooves in contact and with the grooves
disposed at an angle of at least 45°, and most preferably
at an angle of substantially 90°. This embodiment creates
the decorative illusion of a flame in the light tube.
Colored filters can be used to provide images of flames of
different colors.
Another embodiment of the present invention
comprises a first sheet of optical light film connected to
an outer, protective sheet of a second material in~an area
remote from t:he edges of the two sheets. The opposing
longitudinal edges of both sheets are configured such that
the second edge of the optical light film is positioned
between the first edge of optical light film and the first
edge of the oul~er protective sheet while the second edge of
the outer protective sheet is connected with a first edge
region of the protective sheet. This light tube provides
a sheet of optical .Light film substantially surrounded by
- 5 -
an outer, protective sheet which facilitates maintaining
the optical light film in a clean, dry and optically
efficient condition.
Another a:~pect of the present invention comprises
connecting two sheets in a manner similar to that described
above and disposing at least one sheet of optical light
film between t:he two sheets.
The:>e and. other embodiments are described in
further detail. below.
Figure 1 is a perspective view of a light tube
and bulb of one embodiment of the present invention.
Figure 2 is a cross-sectional view of a connector
used with the light tube illustrated in Figure 1.
Figures 3-5 are cross-sectional views
illustrating t:he arrangement of films and a connector of
two embodiments of t:he present invention.
Figure 6 is a cross-sectional view of an
illumination device of the present invention.
Figures 7-12 illustrate various emitters which
may be used with the illumination device illustrated in
Figure 6.
Figures 1:3 and 14 illustrate an optical light
film of the present invention.
Figures 15 and 16 illustrate the arrangement of
a plurality of optical light films used in another
embodiment of the present invention.
Figures 17 and 18 illustrate the effects of using
.,.,
- 6 -
a tapering light tube of another embodiment of the present
invention.
Figure 19 illustrates an illumination device of
another embodiment of the present invention which utilizes
at least one tapering light tube.
Figure 20 illustrates a tube-in-a-tube embodiment
of the present: invention.
Figures 27. - 28 illustrate methods of the present
invention for disposing a light tube within a preformed
carrier.
Figure 29 illustrates a plunger which is useful
with the methods i17_ustrated in Figures 21 - 28.
Figures 30 and 31 are cross-sectional views of
one embodiment of a light tube of the present invention.
Figures 32 and 33 are cross-sectional views
illustrating another embodiment an optical light tube of
the present invention.
Figures :34 and 35 illustrate a terminal,
overlapping joint of one embodiment of the present
invention.
Figure 36 illustrates a connector ring of another
embodiment of the present invention.
Figure 37 illustrates a still further connector
ring of another embodiment of the present invention.
Figures 3~3 and 39 are partial, cross-sectional
views of a li<3ht carrier of an alternative embodiment of
the present inventic>n.
~~ 1~'~7a ~
Figure 40 illustrates another embodiment of the
present invention for directing light out of a light bulb.
One embodiment of the present invention is -
directed to a light carrier comprising at least one sheet
of optical light film 10 which is maintained in a tube
configuration by a novel joint. The optical light film
preferably ha~~ enough flexibility and sufficient width so
that one longitudinal edge 14 can be moved to a position
proximate the other longitudinal edge 14 thereby forming a
tube, preferably having a generally cylindrical shape.
Unless otherwise specified, the term "optical light film"
is used herein. to re>.fer to flexible films having a surface
comprising a plurality of substantially triangular grooves
which reflect substantially all of the light incident on
the opposite side of the film at an angle of less than
about 28° when fornned into a light tube. Such film is
available front the ~1M Corporation, St. Paul, Minnesota.
According to this embodiment of the present
invention, which is illustrated in Figs. 1-5, the opposing
longitudinal edge regions of an optical light film 10 are
maintained in ~?osition using a generally U-shaped connector
20 proximate bulb 11. With reference to Figure 2 which
illustrates one particularly preferred embodiment of a U-
shaped connector 20, comprising a pliable strip 21 provided
with a first ~~trip of adhesive tape 22 on the top of one
end of the flexible strip and a second strip of adhesive
tape 24 positioned on the bottom of the other longitudinal
edge of strip :z1. The strip 21, which is preferably formed
of a clear pol~~neric material, is then simply configured to
form the generally U-shaped connector 20 illustrated in
Figure 2. As illustrated, according to this embodiment,
the upper side: of the U-shaped connector 20 is preferably
longer than the bottom side and the first adhesive tape 22
affixed to the upper side does not extend to the point on
the strip 20 where the strip 20 is folded. As shown, once
~ ~~'5~a 3
_8_
the flexible ;trip is folded into the U-shape, the second
adhesive tape 24 i~~ on the inner surface of the U-shaped
member and they first adhesive 22 is on an outside surface
of the U- shaped member .
As illustrated, it is not necessary that both
sides of the U-shaped member have the same length. It will
also be noted that t:he adhesive tape may be a double-sided
adhesive tape, i.e., a central carrier having adhesive on
both sides . lore preferably, the adhesive tape can be a
Very High Bond Tape available from the 3M Corporation of
St. Paul, Minnesota which exhibits adhesiveness throughout.
Those skilled in tlhe art will also appreciate that the
thickness of t:he adhesive tape utilized can be varied for
different applications depending upon such factors as the
strength required and any thickness characteristics
inherent in the particular tube design.
According to the illustrated embodiment, a second
flexible sheet 30 substantially surrounds and protects the
optical light film 10. In forming this embodiment, at
least a portion of longitudinal edge 12 of the optical
light film 10 is inserted into the slot defined by the
second adhesizte tape 24 and the inner surface of the U-
shaped connector 20. With reference to Figure 3, a contact
region 32 which is remote from a longitudinal edge of the
second sheet ?.0 is then contacted with the first adhesive
tape 22. The longii:udinal edge region 34 of the second
sheet 30, along with the exposed, upper, outer surface 26
of the U-shaped member, forms a slot for receiving the
other end of the optical light film 10. Prior to
configuring the optical light film 10 to form the
substantially closed light tube, another strip of adhesive
tape 36 is preferably positioned on the bottom surface the
opposing edge of the second sheet 30 proximate opposing
edge 38. In this manner, when the sheets are configured to
place the edge: of the optical light film 10 into the slot
~ ~7~7~ 3
_ g -
defined by the U-shaped member 20 and the first edge region
34 of the second sheet 30, the second edge region 38 of the
second sheet 30 can be readily adhered to the top of the
first edge region 34 of the second sheet 30 in the manner
illustrated in Figure 4. This embodiment is particularly
useful in forming tubes with predetermined diameter ( s ) over
the length of: the tube. Additionally, this embodiment
advantageousl~t permits on-site fabrication of light tube
having subst:antia:lly total (i.e. 360°) internal
reflectance.
Depending upon the intended use of the light
tube, it may be desirable to sandwich one or more sheets of
optical light film between sheets of polymeric material.
According to an alternative embodiment of the present
invention ill,.~strated in Figure 5, this can be readily
accomplished in a fashion similar to the embodiment
illustrated in Figures 2-4 by positioning a sheet of
optical light film 40 on the exterior side of a third sheet
41 which is preferably at least approximately the same size
as the optical. lighi~ film 40 and then inserting the third
sheet 41 into the slots defined above. Namely, one
longitudinal edge of sheet 41 is advantageously inserted
into a first slot defined by an inside wall of the U-shaped
connector 46 and an adhesive 42, and the opposite
longitudinal edge is placed into a second slot defined by
an outside surface 43 of the U-shaped member 46 and an edge
region 44 of the outermost sheet 45. From the present
description, those ~okilled in the art will appreciate that
the upper longitudinal edge regions, as shown in Figures 2-
5, will be held within the second slot in part, due to an
edge bond with the adhesive tape 47 positioned on the
upper, outer ;surface 43 of the U-shaped member 46. This
edge bond provider additional adherence but is not
necessary in order to practice this embodiment of the
present invention.
- 10 -
Another ~ambodiment of the present invention
utilizes the decorative advantages of a light tube in a
novel light fixture. In accordance with the illustrated
embodiment shown in Figure 6, this light fixture comprises
a light sourcE~, preferably comprising a metal halide bulb
51, a ballast 52, a decorative light tube 60 and a light
emitter 75. While the illustrated embodiment shows a metal
halide bulb it is also within the scope of the present
invention to use other types of bulbs, such as sulphur
bulbs. .
Accc>rding to the illustrated embodiment which is
in the form of a hanging light fixture, a support hanger 50
is suitably wired to a supply of electrical power and to
ballast 52 which in turn powers bulb 51. According to the
illustrated embodiment, bulb 51 is preferably positioned
within a protective housing.
As shown in Figure 6, the illustrated housing
comprises outer sle~we 55 and an inner sleeve 56. Outer
sleeve 55 is remova.bly connected to a top cover 54 by a
twist connector 57,. Outer sleeve 55 can therefore be
readily removed by simply rotating outer sleeve 55 relative
to top cover 54. Inner sleeve 56 is advantageously
provided with sufficient openings to allow a person to
change bulb 50 aftE~r outer sleeve 55 has been removed.
Outer sleeve ~~5 can then be raised back into position and
secured to upper support 54.
As shown in Figure 6, light tube 60 is suspended
from inner sleeve 5E.. While those skilled in the art will
appreciate that there are many suitable methods of
connecting light tube 60 to inner wall 56, the illustrated
embodiment utilizes a mechanical connection comprising
screws 57 which pass'. through holes in clips 110 light tube
60. Clips 110 are suspended from flanges 112 which are
connected, for example by welding, to inner wall 56. Clips
110 extended downwardly beyond retaining ring 70 and
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preferably overlap a portion of light tube 60. In order to
provide greater support and reduce the likelihood of damage
to the light tube 60, a substantially rigid support ring 58
is advantageously positioned inside the upper portion of
light tube 60. The substantially rigid ring may be formed
of any suitable material, for example, a metal such as
polished alurninum. The illustrated embodiment also
comprises a spacer S9 in order to maintain the light tube
60 and inner protective wall 56 in a substantially-parallel
spaced relati~~n. Therefore, supporting screws 57 pass
through holes in rigid support ring 58, light tube 60,
spacer 59 and clips 110. Screws 57 do not contact outer
protective sleeve 55 and therefore do not interfere with
the movement ~~f out.er sleeve 55 when it is necessary to
change a light; bulb 51. In this manner, vertical support
is provided to light tube 60 and light tube 60 is also
substantially thermally insulated from the heat of bulb 51.
In order i~o obtain desired lighting effects, it
may be desirable to position lenses, for example colored
lenses, or light filters between bulb 51 and light tube 60.
For this purp~~se, a retaining ring 70 is advantageously
disposed below bulb 51. In the illustrated embodiment, a
lens 53 is maintained in a position substantially
perpendicular to th~~ longitudinal axis of the light tube
with a retaining ring 70 formed of a heat resistant
material. For example, the retaining ring 70 may be formed
of a silicone compound, such as "6750 or 6770 silicon
resin" sold by General Electric Company of Waterford, N.Y.,
which is suffi.cient7~y pliable to allow the retaining ring
70 to be positioned. within the bulb housing and also to
permit the placement. of lenses. The illustrated retaining
ring 70 is pro~~ided with two inwardly facing grooves 71 and
two verticall~~ disposed grooves 72, one opening upwardly
and the other opening downwardly.
As illustrated in Figure 6, light tube 60 of the
.-.
2 ~a 5'~ 5 3
- 12 -
illustrated embodiment advantageously extends upwardly
beyond the upper edge of rigid ring 58 into the lower slot
72 of lens retaining ring 70. A suitable heat-resistant
adhesive may also be used within lower vertical groove 72
for bonding retaining ring 70 onto light tube 60. The
mechanical connection performed by screws 57 provides
support to regaining ring 70. Retaining ring 70 may also
be used to support a clear tempered glass lens. Tempered
glass is particularly advantageous since it prevents some
of the ultraviolet waves and heat emitted by a light source
from harming the polymers used in this illumination device .
It also keeps out dust and moisture. Retaining ring 70 may
also be used t:o support a colored filter 114 in order to
create desired illunnination effect.
While those skilled in the art will appreciate
that variations in the construction of the illustrated
light tube 60 may be' made without departing from the scope
of the present invention, for purposes of illustration, the
light tube shown in Figure 6 is shown as simply comprising
an inner sheet of o~>tical light film 61 and an outer sheet
66 of a prote~~tive polymeric material. From the present
description and drawings, those skilled in the art will
also appreciai~e that a wide variety of designs may be
employed in the con~aruction of light tube 60. The amount
of light exiting through the side walls of the light tube
can be varied i~hrough the use of extractors described above
and/or interru.ption:~ in the optical light film. Figure 6
illustrates an extractor 118 formed into the shape of a
star and a relieved section 119 wherein the optical light
film has been removed in order to interrupt the internal
reflectance in. these>. areas.
The direction of light exiting the bottom of the
light tube ma~,r be controlled by a light emitter. Light
emitter may be' of a wide variety of designs depending on
the desired illumination. The emitter, which is shown in
..~ _
~ 17~7~ 3
- 13 -
greater detail in Figure 7, comprises an outlet cap 75
formed of a heat resistant material, such as a silicone
compound. Ou~~let cap 75 preferably comprises at least an
upper-inwardl5r facing slot 76 and a lower inwardly-facing
slot 77 in th.e same manner as retaining ring 70. Upper
slot 76 is preferably utilized to support a protective,
transparent b~~ttom cover 78 which may be formed of any
suitable, heat-resistant material such as a transparent
tempered glas:3. Bottom cover 78 serves to prevent dust,
other dirt and moisture from entering the interior of the
light tube. Lower slot 77 supports a light emitter 74
which comprises four glass disks positioned substantially
perpendicular longitudinal axis of the light tube.
Another 7_ight emitter 80 is illustrated in
Figures 8 and 9. Light emitter 80 comprises a plurality of
reflectors 81 pivotally supported on hinge 83 in a manner
which permits reflectors 81 to be positioned at various
angles relative to the longitudinal axis of the tube.
According to this embodiment, the user of the light carrier
is provided with the option of reflecting substantially all
incident light back into the light tube or positioning one
of the reflectors at an angle to direct the light out of
the egress end of the tube at an angle to the longitudinal
axis of the light tube.
In the emitter illustrated in Figure 10, a
reflective ring is disposed in the lower slot of outlet cap
75 in order to reflect the portion of the light closest to
the walls of light tube
60 back into the light tube. The outer portion 84 of the
reflective ring is reflective while the inner portion 85 is
transparent.
An alternative embodiment is illustrated in
Figure 11 wherein the lower slot 77 of outlet cap 75
supports a disk having an outer transparent portion 86 and
- 14 -
an inner reflective portion 87. This embodiment of the
present invention reflects the portion of light near the
central longit;udina:l axis of the light tube back into the
tube while a17_owing an outer ring of light to be emitted.
According to a still further embodiment of the
present invent: ion illustrated in Figure 12, a right angle
turning lens 88, m.ay be positioned at an angle of 45° to
the longitudinal axis of light tube 60 in order to direct
the light at an angle substantially perpendicular to the
central longit:udina:l axis of the tube . Those skilled in
the art will appreciate that other lenses could be used for
directing light at different angles.
Tho~~e skilled in the art will also appreciate
that the decorative aspects of the light tubes illustrated
in Figures 6-.L2 can be varied through the use of colored
filters or colored protective polymeric films or tubes.
Another preferred aspect of these embodiments of
the present invention comprise some manner of extracting
light out of these :illuminations devices in the region of
the optical light film. For example, one of the extractors
described above may be utilized. A section of the OLF can
also be cut away to provide a relieved section 119,
preferably in the fc>rm of some decorative shape. From the
present description, it will be appreciated that by
removing a portion c~f the optical light film, the internal
reflectance at such portions of the illumination device is
eliminated. By aligning an extractor with a relieved
section 119 by po;~itioning the extractor either at a
location spaced from the relieved portion or inlaid in the
relieved portion a;s shown in Figure 40, even greater
amounts of 1_Lght c:an be emitted at desired portions.
Various shaper and letters can be cut from the optical
light film or an extractor 89 can be employed in the
manners illustrated in Figures 6 and 40.
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Another a;~pect of the present invention comprises
a light tube formed with an improved optical light film.
According to this embodiment of the present invention which
is illustrated in Figures 13-15, some of the peaks on the
grooved side of an optical light film are modified in order
to reduce the internal reflectance of those areas of the
optical light. film. Those skilled in the art will
appreciate that the internal reflectance property of
optical light film is dependent upon precisely formed
ridges on the: outside surface of a light tube. These
ridges are typically formed with sidewalls converging at
angles of ablaut 9~0°. If, however, these ridges are
modified by re~movinc~ a portion of the peak, light incident
on the modified portion will have a much greater tendency
to "escape" from tl~e light tube than in a conventional
light tube. This embodiment of the present invention
advantageously eliminates the need for supplemental
extractors which are used to reduce the internal
reflectance of a poz.-tion of the optical light film.
With. reference to Figure 13, conventional peak
210 is defined by converging sidewalls 211 which meet at an
angle of about 90° forming a substantially triangular cross
section. Typically, light incident upon one side wall 211
of a tube at an angle of incident less than about 28° will
be reflected to the adjacent sidewall of the same peak and
then reflected internally back into the interior of the
light tube. In the illustrated embodiment, light incident
on a modified portion 215 will escape while light incident
on an unmodified portion 216 of a modified peak will still
be internally reflected.
The peaks of the light film can be modified after
manufacturing in any suitable manner. For example, the
ridges may be precisely milled, scraped, melted, e.g. with
a laser beam, or ii. less precision is required, crushed
between rigid rolle>rs. Those skilled in the art will
- 16 -
appreciate that the amount of light escaping through a
modified peak will be dependent upon the amount of the peak
that has been modified. As shown in Figure 14, a single
ridge can have different degrees of modification in order
to permit a greater amount of incident light to exit at one
end of the tune. Those skilled in the art will appreciate
that a greater amount of light will typically pass'through
the tube (esc:ape) at the end closer to the source of
illumination. Therefore, by modifying a greater portion of
the ridge at the di:~tal end which is further away from the
light source, a sub~~tantially constant amount of light can
be emitted over the entire length of the tube.
In addition to providing the method of modifying
optical light film described above, the present invention
also includes an optical light film which is initially
formed without. perfE~ct peaks in desired areas in order to
allow the escape of light in those regions.
Another embodiment of the present invention
provides a decorative light carrier which creates an
apparently changing illumination, generally in the shape of
a flame, as 'the distance between the observer and the
device changes.. This embodiment, which is illustrated in
Figures 15-16, is formed by placing two sheets of optical
light film int~~ contact, with the ridged sides touching and
with the ridges positioned at an angle of at least 45°,
preferably at least 70° and most preferably substantially
perpendicular. This decorative light tube is most
preferably arranged such that the ridges of the inner
optical light film are arranged in the same direction as
the longitudinal axis of the tube. According to the
preferred illustrated embodiment shown in Figure 16, two
sheets of optical light film are disposed within a
protective outer transparent film 220. The ridges of the
inner optica:L film 230 are preferably positioned
substantially parallel to longitudinal axis L while the
- 17 -
ridges of the outer optical light film 240 extend
circumferentially around the tube.
Another embodiment of the present invention
provides a light tube having a diameter which decreases
toward the di:~tal e:nd 270 of the light tube, i.e., in the
direction await from the source of illumination 271. Since
the amount o:E light escaping from a tube is directly
proportional t:o the amount of light striking the sidewalls
of the tube, at angles less than the critical angle of
reflectance which i~; about 28°, greater quantities of light
can be emitted from the distal end by decreasing the
diameter of the tub= and thereby increasing the incidence
of light on tree sma:Ll end of the tube. Figures 17 and 18
illustrate this principle wherein a light ray emanating
from a light source impinges upon the sidewall of two light
tubes, one having a constant diameter and the other
tapered. As generally illustrated, the taper will increase
the frequency of contacts between a light beam and the
sidewalls of a lighi~ tube. This embodiment is preferably
constructed by cutting a sheet of optical light film into
a trapezoidal shape, shaping the optical light film into a
tapered tube, and securing the ends of the tapered light
tube. The length o:E the tube and the degree of taper are
limited only x>y the starting materials. For example, one
such tapered rube h.as an ingress end with a diameter of
about eight inches which tapers down to an egress diameter
of about four inches; over a longitudinal length of about 4
feet .
From the present description, it will be
appreciated that rings, such as the heat resistant
retaining rinds described above, will have many uses in
illumination devices. Rings constructed in the fashion
illustrated in Figures 6-12 may also be utilized to form
other useful illumination devices. For example, Figure 19
illustrates another use of a tapering light tube 393 and
- 18 -
heat-resistant: rings 392, 394. In this embodiment of the
present invent:ion, <~ light source 390 is positioned within
a light housing 391. The light housing 391, which has a
first diameter, is connected to a tapering light tube 393
with a ring 392. Ring 392 is preferably of the type
illustrated above in Figures 6 - 12. A second ring 394
having a different diameter is utilized to connect the
other end of tapering tube 393 to another light tube which
has a diameter or cross-sectional configuration which is
different from that of light housing 391. This embodiment
of the present invention is particularly suited for
connecting elements that have cross-sections of different
sizes and/or ~ohapes,.
Figure 20 illustrates a still further use for the
illustrated rings wherein a tube-in-a-tube construction is
formed using an :inner retaining ring 310 which is
positioned inside an outer retaining ring 320 having a
larger diameter. In the manner illustrated in Figure 20
the inner retaining ring 310 is positioned by a spacer ring
315 which is held in place by an inwardly facing groove of
outer retaining ring 320. The spacer ring 315 can be
formed of any subst<~ntially rigid material, for example a
metal or a plastic. The spacer ring 315 is most preferably
heat resistant. This tube-in-a-tube construction is
particularly useful for providing a protective casing 340
for a light tube 330 and/or providing a colored or finished
cover to creai~e a desired light effect. Casing 340 can
advantageously comprise a plurality of layers.
Another aspect of the present invention comprises
methods of forming light tubes within pre-formed carriers,
for example ~~olycax-bonate tubes. From the description
below, those ;killed in the art will appreciate that the
methods described herein may also be utilized to form light
tubes in carriers that are not circular in cross-section as
well as carriers that are not completely continuous, i.e.
- 19 -
closed in cross-section. One method of forming light tubes
within a cylindrical carrier is illustrated in Figures 21-
28. These methods are particularly useful in forming light
tubes within :pre-formed cylindrical tubes. For example,
light tubes h;~ving a diameter of 4 inches can be readily
formed in lengths of 20 feet.
With reference to Figure 21, the first step
comprises providing a gutter 410 preferably having a length
equal to the length of the final light tube and a
longitudinal relieved section defined by opposing side
walls of gutter 410 through which an optical light film can
be inserted. From the description above, it will be
appreciated that in order to conduct light, optical light
films used with the various embodiments of the present
invention have a plurality of prismatic grooves/peaks which
face outwardly when the optical light film is formed into
a light tube. In order to prevent these peaks/grooves from
being damaged along the edges of gutter 410, a protective
sheet 430 is advantageously placed between the optical
light film and the gutter 410. The protective sheet 430 is
preferably fox-med o:f a material which has is pliable and
has a substani~ially low coefficient of friction with the
other element: utilized during this assembly procedure.
For example, when the gutter 410 is formed of a
polycarbonate, protective sheet 430 may be formed of a
material such as Tyvek~" sold by DuPont of Wilmington, DE.
With. the protective sheet 430 in place, the
optical light film 420 can then be pushed into gutter 410
with the help of a weighted rod 440 in the manner shown in
Figure 22. The heavy rod 440 is then removed and the
optical light film 420 and protective sheet 430 can be
adjusted inwardly to correspond with the general shape of
gutter 410 in the manner shown in Figure 23. The lower
edge 431 of protective sheet 430 is then folded under the
upper edge 432 in the manner illustrated in Figure 24 and
- 20 -
then the upper edge 432 is also folded inwardly such that
the entire optical .Light film 420 and protective sheet 430
are disposed within gutter 410 in the manner shown in
Figure 25. Since gutter 410 has a diameter less than the
diameter of the tube' 450 into which the optical light film
will be ultimately disposed, gutter 410 is then simply
inserted into an open end of tube 450.
According to this embodiment of the .present
invention, the=_ optical light film 420 is then attached,
e.g. clamped, to the end of outer tube 450 and the gutter
410 and protective sheet 430 are removed from the other
end, leaving optical light film 420 within outer tube 450
in the manner shown in Figure 27. If the optical light
film, due to its inherent resiliency and elasticity, does
not conform to the inner surface of outer tube 450, a
plunger 460, for example having a cross-section such as the
one shown in Figure 29, can be pushed into the interior of
optical light film 420 forcing the optical light film 420
outwardly such that the opposing edges of optical light
film 420 snap into position as shown in Figure 28.
According to another embodiment of the present
invention which provides an alternative method for
installing an optical light film into a closed rigid tube,
the steps illustrated in Figures 21-25 are repeated. The
longitudinal recess of the gutter 410 may optionally be
blocked to ~>revent; the optical light film 420 and
protective sheet 430 from working their way out of gutter
410. In this embodiment, one end of gutter 410 is then
aligned with an open end of outer tube 450, a flexible lead
is fed through outer tube 450 and attached to protective
sheet 430 and optical light film 420. The protective sheet
430 and optical light film 420 are then drawn out the open
end of gutter 410, which is maintained substantially
outside of outer tube 450, and into outer tube 450.
2 175 ~'~ 3
- 21 -
The protecaive sheet 430 is preferably a flexible
material having a low coefficient of friction and is
substantially tear-resistant such that it will not tear
upon contact with t:he edges of the gutter 410. While any
low friction, tear-resistant material can be utilized, the
material which has been found useful is TyvekT"" made by
Dupont, of Wilmington, Delaware.
The protective sheet 430 can then be readily
removed in the' manner described above by clamping one end
of the optical light film 420 to the outer tube 450 and
drawing the protective carrier 430 out the other end. If
the optical film 420 did not conform to the inner surface
of tube 450, for example as shown in Figure 27, the plunger
460 illustrated in 1~igure 29 can again be utilized in the
manner described above.
Unlike methods heretofore described and utilized
in the art, t:he methods of the present invention provide
for ways of ~~ositioning optical light film within rigid
tubes with a minimal. amount of manpower. Previous methods
which required the rolling of a sheet of optical light film
within an outer protective, low-friction sheet required
numerous pairs of hands, and were therefore cost-intensive.
Another disadvantage of such methods was that the rolled-up
optical light film and protective sheet would tend to
unroll and would become very difficult to push into the
outer tube. Another disadvantage is that the fragile
optical light film cannot withstand too much pushing before
fracturing. The methods of the present invention
advantageously minimize the amount of stress placed on the
fragile optical light film.
Another aspect of the present invention comprises
a method of disposing an extractor in a light tube
proximate an optical light film in a neat, efficient
manner. This method is particularly useful with extractors
2~~'~~'~3
- 22 -
which reflect incident light at a variety of different
angles. For examp=le, a product marketed under the name
SCOTCHCALT"" sold by the 3M Company of St. Paul, Minnesota is
one such exi~racto:r. Typically such extractors are
installed using a coating of water to facilitate the
positioning oi_ the extractor on the surface to which the
extractor will. be attached. Those skilled in the art will
appreciate that wetting an optical light film can be
detrimental to the internal-reflectance properties of the
film and should, whenever possible, be avoided. This
method of the present invention therefore comprises first
connecting they extractor to a thin film and then disposing
the extractor/thin film laminate onto the configured sheet
of optical light film. Those skilled in the art will
appreciate that the present method avoids the need for
working with water in the presence of the optical light
film and the inherent risks of wetting the grooves of the
optical light film.
One embodiment of the present invention is
directed to a light carrier comprising at least one sheet
of optical light film 510 which is maintained in a tube
configuration by a novel joint. The optical light film
preferably has. enough flexibility and sufficient width so
that one longitudinal edge 511 can be moved to a position
proximate the other longitudinal edge 512 thereby forming
a tube, preferably raving a generally cylindrical shape.
The manner of forming one light tube of the
present invention is best illustrated with reference to
Figures 30 and 31 wherein an optical light film 510 is
protected by an outer protective sheet 520 with a use of
first connector 530 and a second connector 540. ~ In the
manner illustrated in Figure 30, the first connector 530 is
most preferably disposed slightly remote from longitudinal
edge portion 511 and is also preferably connected to the
outer protective sheet 520 at a contact region slightly
- 23 -
remote from a first longitudinal edge 521. In this manner,
a slot is def_Lned by the outer surface of edge region 511
of optical light fi7_m 510, the connector 530 and the inner
side of edge= region 521 of protective sheet 520.
Therefore, when optical light film 510 is configured into
a tube and the second longitudinal edge region 512 is
brought around proximate longitudinal edge 511, the second
longitudinal edge region 512 can be readily inserted into
the slot. In order to maintain the opposing edges of the
outer protective sheet 520 in position, a second connector
540 is preferably positioned between the outer surface of
protective sheet 520 proximate first longitudinal edge 521
and the inner .surface of protective sheet 520 proximate the
second longitudinal edge 522. As shown in Figure 30, the
second connector 540 can readily be positioned prior to
configuring tree she~=ts into a tube. Since some adhesive
tapes which may be used as connectors with the various
embodiments o:E the present invention are provided with
liners which ~~rotect~ the adhesive surface before use, one
side of such tapes can be adhered to an optical light film
or a protective sheet while leaving the other side of the
adhesive tape covered by the protective liner. That liner
could then be subsequently removed at a different location
prior to final assembly. While one preferred embodiment of
this invention aligns the second connector 540 with the
opposing edge~~~ of protective sheet 520, such alignment is
not necessary in order to obtain the benefits of the
present invention.
The connectors used to join the sheets of the
present invention preferably comprise strips of tape, most
preferably a t,wo-sided adhesive tape or a tape exhibiting
adhesive properties throughout such that both sides and the
edges of the tape a~_e sufficiently sticky. One such tape
is a Very High Bond Tape available from the 3M Corporation
of St. Paul, Minnesota which exhibits adhesiveness
throughout. Particularly a clear Very High Bond Tape
u.
- 24 -
designated "4310" is particularly useful for bonding the
smooth surface's of t:he outer protective sheet 520, while a
white Very Hic~h Bond Tape having the designation "4952" is
particularly usefu7L for connecting the outer, ridged
surface of them optical light film to another surface. It
has been found that the clear tape has a tendency to
withdraw from the grooves on the outer surfaces of an
optical light film resulting in a reduction in adhesion.
Those skilled in the art will also appreciate that the
thickness and/or widlth of the adhesive tape utilized can be
varied for different applications depending upon such
factors as t:he strength required and any thickness
characteristic's inherent in the particular tube design.
The various embodiments of the present invention
can readily be' partially or totally assembled at or close
to the site of their ultimate use. Assembly at such
locations greatly reduces the cost of shipping since the
sheets can be shipped in a flat configuration requiring
much less volume than assembled tubes. These and other
advantages of the present invention will be apparent to
those skilled in the art.
An alternative embodiment of the present
invention is :illustrated in Figures 32 and 33. In this
embodiment, at least one optical light film 610 is
substantially sandwiched between an outer protective sheet
620 and a separate inner protective sheet 650. Those
skilled in the' art will appreciate that inner protective
sheet 650 is most preferably clear. The two protective
sheets are configured and connected in the same fashion as
the optical light film and outer protective sheet
illustrated in Figures 30 and 31. A first connector 630 is
utilized to connect an outer surface remote from a first
edge of region 651 of inner sheet 650 with an inner surface
of outer sheet 620 in a manner that forms a slot which
receives a sec~and edge portion 652 of inner sheet 650. The
2 1775
- 25 -
second edge E~22 of outer sheet 620 is then configured
substantially around the inner protective sheet 650 using
a second connector E~40 while at least one sheet of optical
light film 610 is substantially sandwiched between outer
sheet 620 and inner sheet 650. Since the protective sheets
are not being connected to an optical light film, it is
desirable to use a clear Very High Bond Tape such as the
"4910" tape re:ferenc:ed above.
Thi~~ embodiment of the present invention offers
several significant advantages. Primarily, a plurality of
optical light films can be readily positioned at discrete
locations in the tube leaving sections of the tube without
optical light film. Those skilled in the art will
appreciate that controlled amounts of light and various
patterns can be provided by leaving gaps between discrete
sheets of opt=Lcal light film or by providing light films
having extractors or holes which permit the "escape" of
1 fight f rom the 1 fight: tube .
Illu.minati.on devices of the present invention can
also be connected t their terminal ends in order to
increase the effective length of the device. One aspect of
the present invention, illustrated in Figures 34 and 35,
comprises arranging adjacent sections of a multi-section
tube in an overlapping manner. Unlike the other cross-
sectional views described above, each of these views
illustrates portion; of two separate tube segments which
are joined at their terminal ends. In this illustrated
embodiment, a first segment comprises a terminal edge of a
first sheet of optical light film 950 which extends beyond
the edges of two other sheets 951 and 952 of the first
segment. In a. second segment, the optical light film 960
does not extend to the ends of other sheets 961 and 962.
As shown in F_Lgure 35, when the two segments are joined,
the outer two ;sheets 961 and 962 of the second segment will
overlap the optical light film 950 of the first segment.
~7~a~3
- 26 -
This overlap of sheets from adjacent segments will
strengthen the connection between the segments. As shown
in Figure 35, an additional connector 970 such as a single-
sided tape may be u;~ed to hold the segments together.
Another a~~pect of the present invention comprises
a method of disposing an extractor in a light tube
proximate an optical light film in a neat, efficient
manner. This method is particularly useful with extractors
which reflect incident light at a variety of different
angles. For example, a product marketed under the name
SCOTCHCALT"" sold by the 3M Company of St. Paul, Minnesota is
one such extractor. Typically such extractors are
installed using a coating of water to facilitate the
positioning of: the extractor on the surface to which the
extractor will be attached. Those skilled in the art will
appreciate that wetting an optical light film can be
detrimental to the :internal-reflectance properties of the
film and should, whenever possible, be avoided. This
method of the present invention therefore comprises first
connecting thE= extractor to a thin film, such as G.E.
Lexan° suede film and then disposing the extractor/thin
film laminate onto the configured sheet of optical light
film. A suede film advantageously increases the light
scattering effect oi= the extractor. Those skilled in the
art will appre~~iate that the present method avoids the need
for working with water in the presence of the optical light
film and the inherent risks of wetting the grooves of the
optical light film.
Another embodiment of the present invention is
directed to a light carrier comprising an optical light
film disposed within. two substantially transparent sheets.
As illustrated in Figures 38 and 39, an optical light film
1010 comprises a first edge region 1011 and a second edge
region 1012. According to this illustrated embodiment, a
connector 103() is advantageously positioned remote from
- 27 -
edge 1011 of optical light film 1010 and contacts a
transparent middle sheet 1020 at a position remote from a
first longitudinal edge 1021 of the middle sheet 1020. In
this manner, connector 1030 thereby forms a slot into which
the opposite edge portion 1012 of optical light film and/or
longitudinal edge rE~gion 1022 of middle sheet 1020 may be
inserted when the films are formed into a generally tube
configuration, as illustrated in part in Fig. 39. An outer
sheet 1030 com.prise~> a first edge region 1031 and a second
edge region 1032. According to this preferred embodiment
of the preseni~ invention, the opposing longitudinal edge
regions of the outer sheet 1030 are positioned in abutting
relation when the light carrier is formed. In order to
effect this desired configuration, a second connector 1040
is positioned on the outer surface of middle sheet 1020 at
a position remote from first longitudinal edge 1021 and in
alignment with edge region 1031 of outer sheet 1030. In
this manner, the edges of connector 1040 and first edge
region 1031 ar~~ most preferably aligned. A third connector
1050 is advant,~geously disposed on the inner surface of the
second edge region 1032 of outer sheet 1030 such that when
the outer sheet 1030 is formed into a generally tubular
configuration, the third connector 1050 connects the second
edge region 1032 of outer sheet 1030 with the outer surface
of first edge portion 1021 of middle sheet 1020. As shown
in Fig. 39, the edges of outer sheet 1030 are
advantageously, but not necessarily, disposed in abutting
relation in order to provide a light carrier having a
smooth outer surface.
While different types of connectors may be
utilized without departing from the scope of this
embodiment of the present invention, one preferable
material for first connector 1030 comprises a double-sided,
opaque tape spy=cifically designed to hold the outer grooves
of optical light film 1010 securely for extended periods of
time. Connectors 1040 and 1050 may comprise substantially
- 28 -
transparent double-:aided tapes. For example, the adhesive
tape can be a Very High Bond Tape available from the 3M
Corporation of St. Paul, Minnesota which exhibits
adhesiveness t~hrougl'nout. Those skilled in the art will
also appreciate that the thickness of the adhesive tape
utilized can b~~ varied for different applications depending
upon such factors as the strength required and any
thickness characteristics inherent in the particular tube
design.
According to one preferred embodiment of the
present invention, the middle film comprises Lexan°
available from G.E;. Plastics, Inc., U.S.A. having a
matte/velvet finish, e.g. Model 8B35, which is a diffusing
film. The outer sheet preferably comprises Lexan° and most
preferably comprises enhanced ultraviolet stability for
outdoor use. For example, Lexan~ Model HP92W, also
available from G.E. Plastics, U.S.A., offers desirable
ultraviolet stability and abrasion resistance.
From. the present description, it will be
appreciated that rings, such as the heat resistant
retaining rinds described above, will have many uses in
illumination devices. Rings constructed in the fashion
illustrated in Figures 36 and 37 may also be utilized with
other illumination devices.
Figure 36 illustrates a silicon ring of the
present invention comprising a single axial slot and a
radial slot. The axial slot is defined by an inner wall
810 and an outer wall 820 which extend from a body portion
830. An a~:ial groove 840 faces inwardly in this
illustrated embodiment. Inwardly facing radial groove 840
may be utilized to support a lens, a piece of tempered
glass, a mirror, or some other desired element. The ring
illustrated in. Figure 36 the axial groove can be utilized
to receive a :portion of a lamp housing or a light tube.
- 29 -
Additionally, from the present description, those skilled
in the art will appreciate that other connecting members
can be connected to the illustrated ring, for example, to
body portion 830 in order to connect other 'desired
elements. For example, the rim of a light tube could be
positioned within th.e axial slot while a lamp housing could
be connected to body portion 830. As illustrated in Figure
37, one embodiment of the present invention comprises a
double axial slot cc>nfiguration wherein the retaining ring
comprises an upper axial slot 705 and a lower axial slot
706. The upper axial slot 705 being defined by inner wall
720 and outer wall '730 and the lower axial slot 706 being
defined by outer wall 740 and inner wall 750. In this
particular emloodiment, upper slot 705 receives optical
light film 710 and lower slot 706 receives bulb housing
700. Flange 760 projects from inner wall 750 and into
lower slot 706 and acts as a retaining means for bulb
housing 700. Bulb housing 700 comprises a recess 715 for
receiving flange T60 to retain bulb housing '700 in
position. From the present description, those skilled in
the art will appreciate that the ring shown in Figures 36
and 37 have bz-oad applications with illumination devices.
While the up~~er and lower axial slots above have been
generally described as being vertically oriented, it is
conceivable that th.e slots could be disposed in a more
horizontal fashion or at virtually any angle.
