U.S. patent application number 11/031497 was filed with the patent office on 2005-06-16 for light tube system for distributing sunlight or artificial light singly or in combination.
Invention is credited to Eisenman, James A., Johanson, Walter A..
Application Number | 20050128728 11/031497 |
Document ID | / |
Family ID | 46204210 |
Filed Date | 2005-06-16 |
United States Patent
Application |
20050128728 |
Kind Code |
A1 |
Eisenman, James A. ; et
al. |
June 16, 2005 |
Light tube system for distributing sunlight or artificial light
singly or in combination
Abstract
Hybrid lighting systems use light distributor tubes to
distribute artificial light and natural sunlight through the same
distributor tubes. 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 into the ends of tubes designed to distribute
such light. 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
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 system is connected to the light distribution tubes
through a pair 90.degree. 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, 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.
Inventors: |
Eisenman, James A.; (Laurel
Hollow, NY) ; Johanson, Walter A.; (St. Paul,
MN) |
Correspondence
Address: |
Daniel P. Burke, Esq.
GALGANO & BURKE, LLP
Suite 135
300 Rabro Drive
Hauppauge
NY
11754
US
|
Family ID: |
46204210 |
Appl. No.: |
11/031497 |
Filed: |
January 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11031497 |
Jan 7, 2005 |
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|
09917336 |
Jul 27, 2001 |
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6840645 |
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60221604 |
Jul 28, 2000 |
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Current U.S.
Class: |
362/1 |
Current CPC
Class: |
G02B 6/0096 20130101;
F21S 19/005 20130101; F21S 11/00 20130101 |
Class at
Publication: |
362/001 |
International
Class: |
F21V 007/00 |
Claims
1. A hybrid lighting system comprising: means for concentrating
sunlight; a light distributor tube comprising two ends, a
longitudinal axis and means for redirecting light entering an end
of said tube out of said tube away from said longitudinal axis; and
means for directing concentrated sunlight into said light
distributor tube.
2-14. (canceled)
15. A hybrid lighting system according to claim 1 comprising means
for aiming said sunlight concentrating means toward the sun.
16. A hybrid lighting system according to claim 15 wherein said
aiming means comprises at least two reflectors disposed in two
relatively rotatable supports, wherein a first rotatable support is
rotatable about a first axis and a second rotatable support is
rotatable about a second axis which is perpendicular to said first
axis.
17. A device for changing the size of a substantially collimated
beam of light comprising: a first generally parabolic reflector
comprising a first focal length; a second generally parabolic
reflector comprising a second focal length which is different from
said first focal length, wherein said first reflector and said
second reflector are positioned to have a common focal point.
18. A device for changing the size of a substantially collimated
beam of light according to claim 17 wherein said first reflector
and said second reflector are positioned to have a common
longitudinal axis.
19. A device for providing collimated artificial light comprising:
an elliptical reflector comprising a first focal point and a second
focal point; a parabolic reflector comprising a focal point; a
source of artificial light positioned at said first focal point of
said elliptical reflector; wherein said elliptical reflector and
said parabolic reflector are positioned so that said second focal
point of said elliptical reflector is common to said focal point of
said parabolic reflector.
20-44. (canceled)
Description
RELATED APPLICATION DATA
[0001] This application claims the benefits of U.S. Provisional
Patent Application No. 60.backslash.221,604 filed on Jul. 28,
2000.
[0002] 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
[0003] 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.
[0004] Solar interior illumination is a relatively lowtech
alternative source, and offers huge saving in terms of fossil fuel.
Except for window panes and sky lights, however, 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.
[0005] One improvement in the use and distribution of light has
come with the inventions disclosed in U.S. Pat. No. 6,014,849 owned
by the Ply-Light Corporation of Saint Paul Minn. and sold under the
trademark Ply-Light. The tubes receive substantially collimated
light and distribute it efficiently over large areas in the form of
diffused i.e. uncollimated, light. The Ply-Light.RTM. 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 aspect of the
present invention addresses the technology for converting
uncollimated artificial light sources to substantially collimated
light for more efficient use in the new tubes.
[0006] 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 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.
[0007] 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
[0008] 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.
Pat. No. 6,014,489.
[0009] 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 system is connected to the light distribution tubes
through a pair 90.degree. 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.
[0010] 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.
[0011] 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.
[0012] 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 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 1/2 (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.
[0013] 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.
[0014] 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.
[0015] 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.
[0016] These and other advantages of the various embodiments of the
present invention are described in greater detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic view of one embodiment of the present
invention.
[0018] FIG. 2 is a schematic view of an embodiment of the present
invention from above.
[0019] FIG. 3 is a top view of a parabolic reflector of an
embodiment of the present invention.
[0020] FIG. 4 is another sunlight collector and concentrator of the
present invention.
[0021] 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.
[0022] FIGS. 10-13 illustrate components of one preferred device
for blending artificial and natural light of the present
invention.
[0023] FIGS. 20-23 illustrate various light beam splitters of the
present invention.
[0024] FIG. 24 illustrates a device of the present invention for
changing the diameter of a collimated beam of light.
[0025] FIG. 25 illustrates the device of FIG. 24 connected to a
light distributor tube.
[0026] FIG. 26 is a cross-sectional diagramatic view of a device
for collimating artificial light of the present invention.
[0027] FIG. 27 illustrates the device of FIG. 26 connected to a
light distributor tube.
[0028] FIG. 14 illustrates one source of artificial light useful
with the present invention.
[0029] FIG. 15 is a graphic display of the intensity of light
distributed from the artificial light source shown in FIG. 31.
[0030] 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.
[0031] FIG. 18 illustrates an alternative device for collimating
light from an artificial light source.
[0032] FIG. 19 illustrates the device shown in FIG. 17 attached to
a light distributor tube.
[0033] 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.
[0034] FIG. 30 illustrates another embodiment of the present
invention.
[0035] FIG. 31 illustrates another arrangement of the present
invention.
[0036] FIG. 32 illustrates still a further embodiment of the
present invention.
[0037] FIGS. 33 and 34 illustrate an other embodiment of the
present invention.
[0038] FIGS. 34A-D illustrate a preferred light distributor tube
useful with the present invention.
DETAILED DESCRIPTION
[0039] Various embodiments of the present invention relate to
systems for collecting 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 order to facilitate installation a large parabolic reflector can
be formed in segments as shown in FIG. 3.
[0040] FIG. 4 illustrates a preferred arrangement for collecting,
concentrating and recollimating sunlight comprising in large
concave parabolic reflector 110, a large convex 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
concentrator also 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.
[0041] 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 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.
[0042] 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. Pat. 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.
[0043] 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.
[0044] 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.
[0045] 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.
[0046] FIG. 8 is a segmented view of the upper and lower
elbows.
[0047] 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.
[0048] 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.
[0049] 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 light baffle 99 is particularly useful when
using distributor tubes of the type shown in U.S. Pat. No.
6,014,489 which comprise a gradually tapering light distributor for
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.
[0050] 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.
[0051] 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.degree., 90.degree., 180.degree. and 270.degree.
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.degree. and 155.degree., and between 205.degree. and
335.degree.. 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 0.5
inches and the parabola is designed to be connected with a tube
having a diameter of 51/2 inches, then the portion of the light
between 135.degree. and 155.degree. and between 205.degree. and
225.degree. 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.
[0052] 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.degree. and 155.degree. and between 205.degree.
and 225.degree. 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.
[0053] FIG. 17 is another representation of a parabolic reflector
comprising a serrated extension ring of the type shown in FIG.
16.
[0054] 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 blender device, as
desired. Parabolic reflective surface 297 and parabolic reflector
298 share a common focal point F' as indicated in FIG. 18.
[0055] 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.
[0056] As noted above, in the illustrated embodiments, the natural
sunlight and artificial light are blended using beam splitters
arranged at 45.degree. 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.
[0057] 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 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.
[0058] 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.
[0059] 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.degree. 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 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.degree. 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.degree. angle of incidence.
[0060] 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.
[0061] 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.
[0062] 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.
[0063] 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
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.
[0064] 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 reflector 440.
Parabolic reflector440 then reflects a concentrated, collimated
beam of sunlight onto a reflector 450 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.
[0065] 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 blended with artificial light from
an artificial light source 555 or can go directly to a light
distributor tube 556.
[0066] 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 source(s) can be
used singly, i.e. without the alternate source.
[0067] 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 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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