Note: Descriptions are shown in the official language in which they were submitted.
CA 02395010 2002-07-25
LIGHT TUBE SYSTEM FOR DISTRIBUTING SUNLIGHT
OR ARTIFICIAL LIGHT SINGLY OR IN COMBINATION
The present invention is related to lighting systems using sunlight,
artificial
light or both simultaneously in any proportion in a common light distribution
system.
BACKGROUND OF THE INVENTION
Fossil fuel is a finite resource, the burning of which has incipient
environmental consequences. An increase in the use of alternative energy
sources is
desirable, as is better efficiency in the use of all energy. Photovoltaic
generation of
electricity is a broad, high tech energy source but still has limitations with
respect to scale
and storage.
Solar interior illumination is a relatively low tech alternative source, and
offers
huge saving in terms of fossil fuel. Except for window panes and sky lights,
however,
CA 02395010 2002-07-25
interior solar lighting has been clumsy, costly and difficult because both the
intensity and
the angles of sunlight vary so widely with time of day, with the seasons, and
with the
weather. Meanwhile, lighting systems which use a lot of electricity while the
sun shines are
almost universal.
One improvement in the use and distribution of light has come with the
inventions disclosed in U.S. Patent No. 6,014,849 owned by the Ply-Light
Corporation of
Saint Paul Minnesota and sold under the trademark Ply-Light. The tubes receive
substantially collimated light and distribute it efi~iciently over large areas
in the form of
diffused i.e. uncollimated, light. The Ply-Light~ tubes distribute artificial
light which starts
life inherently uncollimated. Since these tubes work best if their inputs are
in the form of
substantially collimated light, one aspectofthe present invention addresses
the technology
for converting uncollimated artificial light sources to substantially
collimated light for more
efficient use in the new tubes.
The technology for making artificial light is improving with new, powerful,
energy-efficient light sources such as metal halide-based electric lamps as
well as small
glass envelopes filled with gaseous sulphur compounds that virtually burst
into
luminescence in the presence of a microwave electromagnetic field. The basic
appeal is
savings in fuel required to make the electricity to power the new lights.
Since the new light
sources are centralized and can use light-distributing tubes, they can also
eliminate some
labor-intensive and costly procedures such as installing many discrete, heat-
generating
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electric light fixtures, to say nothing of the life time chore of changing
many dead bulbs and
fluorescent tubes, often in inaccessible places, and disposing of them safely.
So single lighting systems which can efficiently distribute either solar light
when the sun shines or controllable artificial light through the same tubes
when sufficient
sunlight is not available, will have appeal to the environmentalist and
economist alike. The
various aspects of the present invention are directed to this new technology.
The new
high-intensity light sources, however, crave better and more efficient means
of distribution.
SUMMARY OF THE INVENTION
Various embodiment of the present invention provide devices for gathering
uncollimated light from conventional sources (such as electrically energized
arcs or
filaments housed in evacuated or gas filled glass envelopes) and directing the
light in the
form of a beam of substantially collimated light into the ends of tubes
designed to distribute
such light, such as those disclosed in U.S. Patent No. 6,014,489.
Aspects of the present invention also provide devices for gathering and
concentrating inherently collimated sunlight to be fed into the same light
distributing tubes
used by the artificial light. One preferred embodiment of the present
invention comprises
a light gathering and concentrating system in the form of a pair of opposed
parabolic
reflectors, one which is preferably large, e.g. having a diameter of five
feet, and the other
much smaller, e.g. the size of the much smaller distribution tubes. This light
gathering
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system is connected to the light distribution tubes through a pair 90°
elbows which are
rotatable in the X and Y axis in order to track the location of the sun in the
sky. The two
parabolic reflectors are positioned to share a common focal point so that the
larger
reflector will direct the sunlight through the focal point of the smaller
reflector, which will,
by optical definition, reflect the light as concentrated, collimated light. A
central aperture
in the larger reflector passes the concentrated beam on its way to the
distribution tubes.
The collimation can be accomplished, for example, by precision, parabolic
reflectors, with or without attachments or by directing the internally
reflected light from an
elliptical reflector into the back end of a parabolic reflector, with the
light source positioned
at the first focal point within the elliptical reflector and the parabolic
reflector located with
its own focal point in precise coincidence with the second focal point of the
elliptical
reflector. The collimated light output is then directed to the distributing
tubes, changing
direction where required, using reflectors, e.g., planar reflectors.
Another preferred embodiment described in further detail below comprises
two sets of larger-smaller parabolic reflectors arranged to minimize the
losses inherently
caused by the position of the smaller parabolic reflector in the path of the
sun striking the
larger parabolic reflector.
This unique use of dual light sources with a single distribution system is
made
possible by a light blending device which preferably comprises two oppositely
directed,
planar, partially reflecting surfaces both of which pass light bi-
directionally through both
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surfaces at the same time. The two types of light, in this case sunlight and
artificial light,
are arranged into two substantially collimated light beams which intersect
within a certain
range of angles. The light blending device is placed at the intersection of
the two beams
at an angle which is precisely half of the angle of intersection of the beams.
According to
one preferred embodiment, two output light beams are produced, fulfilling the
equation'h
(S + A) where S is the beam of sunlight and A the beam of artificial light.
The outputs can
also be all sunlight, all artificial light or any combination of the two. The
outputs are
conducted into light distributing tubes designed to use substantially
collimated light. In a
system based on solar light supplemented or supplanted by artificial light,
the intensity of
the artificial light is controlled as a function of the intensity of the light
in the area being
illuminated. The intensity of the artificial light is automatically adjusted
up or down as
required to maintain uniform lighting. Passing clouds in the daytime, will
result in a small
increase in the artificial light level while the darkness of night can result
in a shift to artificial
light.
According to another aspect of the present invention, one or more of the
several reflectors in the system can be made to separate the visible spectrum
of the light
from the invisible (including infra red). The visible light can be directed
into the light
distribution system while the invisible light can be filtered to eliminate it.
The visible light
will be "cool", significantly lowering the demand for air conditioning.
Another advantage
of the present systems is that they allow the artificial light sources to be
centralized where
their excess heat can be vented to the outdoors in warm weather and into the
building in
cold weather.
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Preferred embodiments of the present invention comprise light sensors which
can monitor and adjust the amount of artificial light added to the system
necessitated by
fluctuations in available sunlight.
Other aspects of the present invention comprise improved sunlight
collimators and concentrators, improved reflectors for both natural and
artificial light, and
improved connectors for connecting artificial light with distributor tubes.
These and other advantages of the various embodiments of the present
invention are described in greater detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of one embodiment of the present invention.
FIG. 2 is a schematic view of an embodiment of the present invention from
above.
FIG. 3 is a top view of a parabolic reflector of an embodiment of the present
invention.
FIG. 4 is another sunlight collector and concentrator of the present
invention.
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FIGS. 5-9 illustrate the attachment of the sunlight concentrator of FIG. 4
with
light distributor to according to one preferred embodiment of the present
invention.
FIGS. 10-13 illustrate components of one preferred device for blending
artificial and natural light of the present invention.
FIGS. 20-23 illustrate various light beam splitters of the present invention.
FIG. 24 illustrates a device of the present invention for changing the
diameter
of a collimated beam of light.
FIG. 25 illustrates the device of FIG. 24 connected to a light distributor
tube.
FIG. 26 is a cross-sectional diagramatic view of a device for collimating
artificial light of the present invention.
FIG. 27 illustrates the device of FIG. 26 connected to a light distributor
tube.
FIG. 14 illustrates one source of artificial light useful with the present
invention.
FIG. 15 is a graphic display of the intensity of light distributed from the
artificial light source shown in FIG. 31.
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FIGS. 16 and 17 illustrate a device designed to maximize the amount of
useful collimated light obtained form the artificial light source shown in
FIG. 31.
FIG. 18 illustrates an alternative device for collimating light from an
artificial
light source.
FIG. 19 illustrates the device shown in FIG. 17 attached to a light
distributor
tube
FIGS. 28 and 29 illustrate an embodiment of the present invention designed
to eliminate areas of high intensity immediately proximate an artificial light
source and to
increase the amount of collimated light directed into a light distributor
tube.
FIG. 30 illustrates another embodiment of the present invention.
FIG. 31 illustrates another arrangement of the present invention.
FIG. 32 illustrates still a further embodiment of the present invention.
FIGS. 33 and 34 illustrate an other embodiment of the present invention.
FIGS. 34A-D illustrate a preferred light distributortube useful with the
present
invention.
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DETAILED DESCRIPTION
Various embodiments of the present invention relate to systems forcollecting
and concentrating sunlight and directing concentrated sunlight and/or
collimated artificial
light into at least one light distributor tube. FIG. 1 is a schematic of one
embodiment of the
present invention comprising a parabolic reflector 10 having a central through
hole 15
which allows for the passage for concentrated sunlight reflected off parabolic
reflector 20.
Parabolic reflector 10 and concave parabolic reflector 20 are positioned to
share a
common focal point F such that sunlight entering in the direction of arrow S
will strike
parabolic reflector 10 and be reflected to concave parabolic reflector 20
which will then
reflect the light through the central hole 15 in parabolic reflector 10. The
combination of
the parabolic reflector 10 and concave parabolic reflector 20 concentrate and
recollimate
the sunlight for introduction into a single distributor system. This
illustrated system also
comprises four light tubes 30, three artificial light sources 40, light
blender devices 50 and
light sensors 60. The sunlight passing down through entrance tube 25 is
reflected into
distributor tubes 30 and, where desired, supplemented or supplanted by the
artificial light
from artificial light sources 40. FIG. 2 is a plan view of a similar
embodiment as viewed
from above when the parabolic reflector is facing upwardly. In orderto
facilitate installation
a large parabolic reflector can be formed in segments as shown in Fig. 3.
FIG. 4 illustrates a preferred arrangement for collecting, concentrating and
recollimating sunlight comprising in large concave parabolic reflector 110, a
large convex
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parabolic reflector 120, the back end of which forms a small parabolic
reflector 111 and a
smaller convex reflector 121. The large concave parabolic reflector 110 and
large convex
parabolic reflector 120 are positioned to share a common focal point.
Similarly, smaller
concave parabolic reflective surface 111 and small convex parabolic reflector
121 also
share a common focal point. This preferred sunlight concentrator
advantageously
minimizes the amount of lost sunlight which is blocked by the non-reflective
side of reflector
20 shown in FIG. 1. In the embodiment shown in FIG. 4, the sunlight striking
parabolic
reflector 110 is directed to concave reflector 120 and then reflected as a
concentrated,
collimated beam of sunlight through center hole 115 in parabolic reflector 110
and to the
distributor system. Similarly, sunlight striking parabolic reflective surface
111 on the back
of reflector 120 is directed to reflector 121 which then directs that sunlight
as a collimated
concentrated beam through the center hole of parabolic reflector 120 and to
the light
distributing system. This preferred light concentratoralso comprises sunlight
detectors 116
which are used to maintain the proper orientation of the sunlight concentrator
in order to
maximize the amount of sunlight striking the parabolic reflectors 110 and 111.
It is
preferable to have at least three and possibly more sunlight detectors 116 at
spaced
positions around the periphery of the support for parabolic reflector 110.
Sunlight detectors
116 are preferably linked to suitable controls for affecting the movement of
the entire
sunlight concentrator, i.e., the precise controls, linkages, computer hardware
software.
FIG. 5 illustrates one preferred embodiment of the present invention in the
form of a hybrid lighting system which utilizes natural sunlight and/or
artificial light at any
given time. This illustrated embodiment includes the sunlight concentrator of
the type
CA 02395010 2002-07-25
shown in FIG. 4. The sunlight concentrator is connected to two elbows each
comprising
a reflector. Upper elbow 70 receives light directly from the sunlight
concentrator and
comprises a planar reflector, e.g. a mirror 71 which reflects incoming
sunlight at an angle
of 90 degrees. Reflector 71 can be rectangular or oval, or any other desired
shape which
adequately reflects sunlight received from the sunlight concentrator. Upper
elbow 70 is
advantageously rotatable about axis A-A and is controlled by motor 75 and
suitable
linkages. The linkages can be belts, gears or other linkages as desired. Light
exiting
upper elbow 70 enters lower elbow 80 which is rotatable about axis B-B. Lower
elbow 80
comprises a reflective surface such as a mirror which redirects the incoming
sunlight
downwardly through tube section 89 and through the roof. While the illustrated
embodiments show natural sunlight being directed through a roof, this is
solely for
purposes of illustration. The advantages of the present invention can be
enjoyed with
systems that direct sunlight outside of a building or into other areas where
illumination is
desired. Lower elbow 80 is also advantageously rotatable around axis B-B and
is
controlled by motor 85 which is linked to lower elbow 80 by suitable linkage.
The combined
effect of the rotation of upper elbow 70 and lower elbow 80 permits the
sunlight
concentrator to track the sun through any position in the sky while always
directing the
sunlight down tube 89. In this illustrated embodiment tube 89 directs the
concentrated
sunlight through roof 88 into a light blender. Tube 98 can, for example, be
formed of a
structural material such as aluminum and preferably has an internal surface
which is highly
reflective.
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In the embodiment illustrated in Fig. 5, sunlight exiting tube 89 strikes a
beam
splitter 90 which reflects a first portion of the sunlight into light
distributor tube 91 while
allowing another portion of the sunlight to pass through beam splitter 90 to
reflector 92
which reflects the sunlight into light distributor tube 93. While the
preferred light distributor
tubes are of the type disclosed in U.S. Patent No. 6,014,849, other forms of
distributor
tubes can be utilized without departing from the scope of the present
invention. Those
skilled in the art will appreciate that if other types of distributor tubes
are utilized, then it
may be necessary to take steps to uncollimate the light in order to provide
for proper light
distribution out of such other light distributor tubes.
In one embodiment, the first side of beam splitter 90 reflects substantially
half
of the incoming sunlight to light tube 91 while allowing the other half to
proceed to reflector
92 and into light tube 93. Artificial light source 95 is used to supplement
and/or supplant
the incoming sunlight. Substantially collimated artificial light from
artificial light source 95
strikes the second side of beam splitter 90 opposite the side first
encountered by incoming
sunlight. Beam splitter 90, according to this illustrated embodiment, allows
half of the
collimated artificial light to proceed relatively unimpeded to light
distributor tube 91 while
reflecting the other half to reflector 92 and ultimately to light distributor
tube 93.
Fig. 6 provides an illustration of how incoming rays of sunlight are
concentrated and transmitted through a sunlight concentrator, upper and lower
elbows and
into a building.
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Fig. 7 is a side view of the portion of the embodiment shown in Fig. 6 above
the roof line with the sunlight concentrator shown in a tilted position.
Fig. 8 is a segmented view of the upper and lower elbows.
Fig. 9 is an enlarged view of the light blender section and distributor tubes
shown in Fig. 6. In this embodiment, tube 89 is connected to a three-piece
blender box
formed by upper segment 101, middle segment 102 and lower segment 103. Light
distributor tube 89 is connected to upper segment 101 with a silicone ring 105
artificial light
source 95 is connected to middle segment 102 of the blender box by a silicone
ring 105
and both light tubes 91 and 93 are connected to their respective blender box
segments by
silicone rings 105. Middle segment 102 of the blender box is connected to the
lower
segment 103 by a silicone ring 106. Each of the light distributor tubes is
provided with an
end cap 107 which secures a reflector 108 on the end of the distributor tube.
Reflectors
108 direct any light which has not already been directed out of the
distributor tubes back
into the distributor tubes.
Figs. 10, 11, and 12 are elevation views, top views and side views,
respectively, of upper segment 101 of the blender box shown in Fig. 10.
Fig. 13 is a portion of a blender box. The circle on the right is the
connector
105 to an artificial light source 95. This connector 105 holds a light baffle
99 which reflects
light back into the bulb in order to prevent the element in the light
distributor tube. This
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light baffle 99 is particularly useful when using distributor tubes of the
type shown in U.S.
Patent No. 6,014,489 which comprise a graduallytapering light distributorfor
reflecting light
out of the distributor tube. Figs. 34a through 34d provide a representation of
a light
distributor tube 800 connected to an artificial light source 810 by a silicone
ring 805. Figs.
34b, 34c and 34c are cross-sectional views taken along lines BB, CC and DD,
respectively.
These cross-sectional views show the relatively increasing cross-section of
light distributor
820 of this illustrated embodiment as the light distributor gradually
intersects more of the
light beam along the length of the distributor tube 800 as the light beam
travels away from
the artificial light source 810. The baffle 99 is designed to prevent the heat
from the
artificial light source from overheating or burning the distributor 820 if
this type of light
distributor tube is utilized. Other shapes and sizes of baffles can be
utilized without
departing from the scope of the present invention in order to accommodate
different sizes
and shapes of light distributors and/or light distributor tubes.
Fig. 14 is a schematic representation of an artificial light source, e.g. a
Philips
CDM-SA/T 150-watt metal halide bulb which may be utilized with the present
invention.
This type of artificial light source is particularly suitable since it has a
relatively short arc
which is readily positionable at the focal point.
Fig. 15 is a schematic representation of the intensity of artificial light
emanating from the artificial light source shown in Fig. 14. The dark lines on
the draft
indicate the intensity of the beam at various angles relative to the
orientation of the light
source. The angles on the graph in Fig. 15 correspond to the indications of
0°, 90°, 180°
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and 270° shown on Fig. 14. As indicated on the graph in Fig. 15, most
of the artificial light
leaving this artificial light source is directed between 25° and
155°, and between 205° and
335°. If the arc of the light source, which is represented by the small
circle A in the center
of the bulb is placed at the focal point of a parabolic reflector having a
focal length of .5
inches and the parabola is designed to be connected with a tube having a
diameter of 5-
1/2 inches, then the portion of the light between 135° and 155°
and between 205° and 225°
would not hit the reflective surface of the parabolic reflector and therefore
would not be
collimated prior to entry into the light distributor tube. Since some
distributor tubes,
particularly the distributor tubes discussed in the above-referenced patent,
operate most
efficiently when receiving collimated light, it is desirable to collimate the
maximum amount
of light possible.
Fig. 16 illustrates a modified parabolic reflector designed for an artificial
light
source such as that represented in Fig. 15. In this embodiment of the present
invention,
a serrated extension ring 97 having a highly reflective interior surface is
connected to the
end of the parabolic reflector and a central reflector 98 is mounted within
the center of the
parabolic reflector. As generally illustrated in Fig. 16, light exiting the
artificial light source
between angles 135° and 155° and between 205° and
225° strikes the interior, highly
reflective serrated edges of extension ring 97 and are directed toward the
centrally located
reflector 98 which reflects those light beams as collimated light.
Fig. 17 is another representation of a parabolic reflector comprising a
serrated extension ring of the type shown in Fig. 16.
CA 02395010 2002-07-25
Fig. 18 illustrates another embodiment of a reflector system for an artificial
light source designed to capture additional light which would otherwise be
lost as explained
above. According to the embodiment illustrated in Fig. 18, the end of the
parabolic portion
of a reflector is provided with a downwardly sloping, inwardly facing
parabolic reflective
surface 297 which reflects incident light to a centrally located parabolic
reflector 298 which
then redirects the artificial light beams as a collimated, concentrated light
into the
distribution system or light blenderdevice, as desired. Parabolic reflective
surface 297 and
parabolic reflector 298 share a common focal point F' as indicated in Fig. 18.
Fig. 19 is a view of an alternative embodiment, similar to the embodiment
shown in Fig. 10, however, with an improved artificial light reflector having
a serrated
extension ring.
As noted above, in the illustrated embodiments, the natural sunlight and
artificial light are blended using beam splitters arranged at 45° to
the incident light. One
type of beam splitter useful with the present invention comprises a piece of
glass having
alternating sections which are uncoated, i.e. clear, and sections which are
coated with a
reflective material so that at least some incident light is reflected.
Fig. 20 is a schematic diagram illustrating how a beam splitter of this type
operates wherein the arrows designated S represent sunlight and arrows
designated A
represent artificial light. After encountering the beam splitter, the exiting
beams comprise
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CA 02395010 2002-07-25
half sunlight and half artificial light. Figs. 21A, B and C are top, side and
cross-sectional
views of one arrangement for a beam splitter of this configuration.
Figs. 22 and 23 illustrate another form of beam splitter which comprises a
dichroic coating designed to allow certain portions of certain types of light
to pass through
the coating while reflecting the resulting portion of the incident light.
Dichroic coatings can
also be designed to substantially reflect light of certain wave lengths while
allowing light of
other wave lengths to pass through the coating. Dichroic beam splitters
comprise at least
one dichroic coating which reflects a certain portion of either artificial or
natural light while
allowing the balance of the incident light to pass through.
Fig. 22 is a schematic illustration of a dichroic lens wherein the dichroic
(beam splitting) coating is balanced so that half of both the incident
sunlight and incident
artificial light pass through the beam splitter while half of each is
reflected. In this
illustrated embodiment, the beam splitter is advantageously positioned at an
angle of 45°
to each of the incident beams of sunlight S and artificial light A. It may be
possible to orient
a beam splitter at different angles by adjusting the coating and/or the manner
in which
dichroic coating is applied to the substrate. As indicated in this illustrated
embodiment, the
result is a substantially equal amount of artificial light and an equal amount
of sunlight
leaving the dichroic lens. Figs. 23a, 23b and 23c are the top view, side view
and a cross-
sectional view of the dichroic lens shown in Fig. 22. With reference to Fig.
23c, surface
232 is anti-reflective while surface 233 is the beam splitting surface. The
elliptical shape
is design to fit in the opening shown in Fig. 10. As one example of a beam
splitter useful
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with the present invention, a 7.75 inch by 5.5 inch by 3.2 millimeter
borofloat substrate,
having a clear aperture of 7.1 inches by 5 inches and having a surface quality
of 80/50
scratch and dig, was coated on one side with a broad band anti-reflective
coating having
an average reflectance of less than 1 percent for light having wave length of
425-675 nm
at a 45° angle of incidence. The opposite side was coated with a
dielectric beam splitter
with a transmission equal to 50 percent ~ 10 percent for light having a wave
length of 425-
675 nm at a 45° angle of incidence.
For various applications, it can be desirable to use light distributor tubes
of
different diameters and also to couple light sources or tubes transmitting
natural sunlight
to a blender box or to a light distributor tube of a different diameter. Since
the efficiency
of many light distributor tubes is directly related to the ability to provide
collimated light, it
is desirable to always provide collimated light. The device shown in Fig. 24
is utilized to
change the diameter and concentration of a beam of collimated light. This
device can
advantageously either concentrate either a collimated light beam into a
narrower beam or
can expand a narrow beam into a wider beam of collimated light. The
illustrated device
comprises two parabolic reflectors which are arranged to have an identical
focal point. In
the manner illustrated, collimated light entering either side of the device
which strikes a
reflective surface on one side will pass through the common focal point,
strike the reflective
surface on the opposite side of the device and exit in a collimated beam.
Fig. 25 illustrates the use of this device wherein a wide beam of collimated
light is first concentrated and then directed into a light distributor tube.
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Fig. 26 illustrates another device for collimating light from an artificial
light
source comprising an elliptical reflector 271 and a parabolical reflector 272.
According to
this embodiment of the present invention, the illuminated arc of the light
source is
positioned at the first focal point 273 of the elliptical reflector and the
parabolical reflector
is positioned such that its focal point is common with the second focal point
274 of the
elliptical reflector. In the manner illustrated in Fig. 26, light emanating
from the arc at the
first focal point 273 which strikes the interior reflective surface of the
elliptical reflector 271
passes through the second focal point 274 of the elliptical
reflector/parabolical reflector,
then strikes the interior surface of the parabolical reflector and exits as a
collimated beam
of light. Fig. 27 illustrates this improved artificial light source connected
to a light distributor
tube.
Figs. 28 and 29 illustrate another aspect of the present invention which is
designed to improve the even distribution of light from an artificial light
source. When light
is directed from a simple parabolic reflector such as the one shown in Fig. 29
connected
to a light distributor tube, in the area immediately next to the light source,
it is common to
have intensity peaks. It has been found that a more even distribution of light
emanating
from the light distributor tube can be obtained by adding a mirror film 282 to
the end of the
light distributor tube proximate the artificial light source in the manner
illustrated in cross-
section in Fig. 28. This cross-sectional view of a light distributor tube
section comprises
a rigid polycarbonate clear tube 283. The mirror film 282 extends only from
the point
proximate D artificial light source or about 30 inches. The mirror film is
bonded to a lexan
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CA 02395010 2002-07-25
suede film 284. In the same manner. beyond the mirror film a 3M light
enhancement film
designated 3635-100. is bonded to the same lexan suede film 284 Distributor
285 is not
covered with inner lexan HP92W film 281. Light is emitted from this
distributor tube in the
area designated by the arc E at the bottom of the tube. Light is emitted from
this distributor
tube in the area designated by the arc E at the bottom of the tube.
Fig. 30 illustrates an alternative embodiment of the present invention wherein
a flat reflector surface 410 is pivotally supported on a rotatable sunlight
concentrator 420
comprising a parabolic reflector 430 which directs sunlight reflected off of
flat reflector 410
onto a smaller parabolic reflector440. Parabolic reflector440 then reflects a
concentrated,
collimated beam of sunlight onto a reflector450 which directs the
concentrated, collimated
beam of sunlight down through the roof 401 into a light blending device. In
this illustrated
embodiment, tilting reflector 410 preferably has a diameter equal to the
diameter of large
parabola 430 in horizontal dimension and 1.75 times the diameter of the large
parabola
430 in vertical dimension in order to maximize the light collected from the
sun.
Fig. 31 illustrates a simpler device wherein sunlight is reflected but is not
concentrated. According to this simplified device, a planar reflector 510
which is supported
for rotation in both the X and Y axis by support 515 reflects sunlight to a
second planar
reflector 510 which then simply directs the reflected beam of sunlight down
through a
skylight 530. The sunlight passes through beam splitters 540 and 541 and into
beam
concentrators 550, 551, respectively. Light concentrators 550 and 551 are of
the general
type shown above in Figs. 24 and 25. The resulting concentrated light can then
be
CA 02395010 2002-07-25
blended with artificial light from an artificial light source 555 or can go
directly to a light
distributor tube 556.
Fig. 32 illustrates an alternative embodiment wherein the sunlight gathering
device is similar to that shown in Fig. 31. However, according to this
illustrated
embodiment, the sunlight is concentrated using a device of the type shown in
Figs. 24 and
25. In this illustrated embodiment, the light concentrated device 600 is
positioned in the
roof 601 of the building. The concentrated beam of collimated sunlight is then
directed into
a blender box comprising a beam splitter 605 where the sunlight can be mixed
with a
collimated beam of artificial light emanating from artificial light source 610
and two resulting
beams of combined natural and artificial light are distributed through
distributor tubes 611
and 612. In this illustrated embodiment, the light distributor tubes are on
different floors
of the illustrated building. As noted above, light from the sun or the
artificial light sources)
can be used singly, i.e. without the alternate source.
While the illustrated embodiments of the present invention show beams of
sunlight passing generally vertically through the roof of a building, it is
also within the scope
of the present invention to pass sunlight through a roof on an angle. The
embodiment of
the present invention shown in Fig. 33 is similar to the embodiment shown in
Fig. 30
wherein a pivotal and rotatable reflector 710 reflects light to a large
parabolic reflector 730
and into a smaller parabolic reflector 740 which then sends the resulting
collimated,
concentrated beam of sunlight through the roof 701 on an angle into the
building where it
21
CA 02395010 2002-07-25
encounters reflector 750 and is then directed into either light distributor
tubes or blender
boxes for possible mixing with artificial light.
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