U.S. patent application number 11/438178 was filed with the patent office on 2007-11-22 for skylight tube with reflective structured surface.
Invention is credited to Paul Jaster, David W. Rillie.
Application Number | 20070266652 11/438178 |
Document ID | / |
Family ID | 38710693 |
Filed Date | 2007-11-22 |
United States Patent
Application |
20070266652 |
Kind Code |
A1 |
Jaster; Paul ; et
al. |
November 22, 2007 |
Skylight tube with reflective structured surface
Abstract
A skylight shaft substrate is rendered internally reflected in
several ways. To limit the formation of focal points that can lead
to hot spots as light travels down the shaft, the shaft substrate
is formed with dimples or longitudinal corrugations.
Inventors: |
Jaster; Paul; (Carlsbad,
CA) ; Rillie; David W.; (San Diego, CA) |
Correspondence
Address: |
ROGITZ & ASSOCIATES
750 B STREET, SUITE 3120
SAN DIEGO
CA
92101
US
|
Family ID: |
38710693 |
Appl. No.: |
11/438178 |
Filed: |
May 22, 2006 |
Current U.S.
Class: |
52/200 |
Current CPC
Class: |
E04D 13/03 20130101;
F21V 7/24 20180201; F21S 11/00 20130101; E04D 2013/0345 20130101;
F21V 7/28 20180201 |
Class at
Publication: |
52/200 |
International
Class: |
E04B 7/18 20060101
E04B007/18 |
Claims
1. A skylight assembly, comprising: a transparent dome; and at
least one skylight shaft substrate extending away from the dome to
convey light entering the dome through the shaft substrate; at
least one surface irregularity being formed on the shaft substrate,
the surface irregularity being selected from the group consisting
of dimples and longitudinal corrugations.
2. The assembly of claim 1, wherein the shaft substrate is metal,
the shaft substrate being polished to provide a reflective surface
without any reflective film incorporated into the assembly.
3. The assembly of claim 1, wherein the shaft substrate is metal, a
reflective metal being deposited directly on the inside surface of
the shaft substrate to render the assembly internally reflective
without incorporating an adhesive into the assembly.
4. The assembly of claim 1, wherein the shaft substrate is a
reflective film, a metallic substance being vapor-deposited onto
the film.
5. The assembly of claim 1, wherein the shaft substrate is a
reflective film, the film including a reflective multi-layer
polymer composite.
6. The assembly of claim 1, comprising plural surface
irregularities established by longitudinal corrugations, each
corrugation defining a midline and opposed edges, a first angle
being formed between tangents to edges of first corrugations, a
second angle being formed between tangents to edges of second
corrugations, the first angle being different than the second
angle.
7. The assembly of claim 6, wherein first corrugations alternate
with second corrugations around the circumference of the shaft
substrate.
8. The assembly of claim 6, wherein the corrugations are V-shaped
in transverse cross-section.
9. The assembly of claim 6, wherein the corrugations are U-shaped
in transverse cross-section.
10. The assembly of claim 1, comprising plural surface
irregularities established by plural dimples, each dimple defining
a center and a periphery, a tangent to the periphery establishing
an angle with respect to a tangent to the center of no more than
two degrees.
11. A skylight assembly, comprising: a transparent dome; and at
least one skylight shaft substrate extending away from the dome to
convey light entering the dome through the shaft substrate; plural
surface irregularities being formed on the shaft substrate, wherein
the shaft substrate is metal, a reflective metal being deposited
directly on the inside surface of the shaft substrate to render the
assembly internally reflective without incorporating an adhesive
into the assembly.
12. The assembly of claim 11, wherein the surface irregularities
are selected from the group consisting of dimples and longitudinal
corrugations.
13. A skylight assembly, comprising: a transparent dome; and at
least one skylight shaft substrate extending away from the dome to
convey light entering the dome through the shaft substrate; plural
surface irregularities being formed on the shaft substrate, wherein
the shaft substrate is metal, the shaft substrate being polished to
provide a reflective surface without any reflective film
incorporated into the assembly.
14. The assembly of claim 13, wherein the surface irregularities
are selected from the group consisting of dimples and longitudinal
corrugations.
15. A skylight assembly, comprising: a transparent dome; and at
least one skylight shaft substrate extending away from the dome to
convey light entering the dome through the shaft substrate; plural
surface irregularities being formed on the shaft substrate, wherein
the shaft substrate is a reflective film, a metallic substance
being vapor-deposited onto the film.
16. The assembly of claim 15, wherein the surface irregularities
are selected from the group consisting of dimples and longitudinal
corrugations.
17. A skylight assembly, comprising: a transparent dome; and at
least one skylight shaft substrate extending away from the dome to
convey light entering the dome through the shaft substrate; plural
surface irregularities being formed on the shaft substrate, wherein
the shaft substrate is a reflective film, the film including a
reflective multi-layer polymer composite.
18. The assembly of claim 17, wherein the surface irregularities
are selected from the group consisting of dimples and longitudinal
corrugations.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to skylights.
BACKGROUND OF THE INVENTION
[0002] In U.S. Pat. Nos. 5,896,713 and 6,035,593, both of which are
owned by the same assignee as is the present invention and both of
which are incorporated herein by reference, tubular skylights are
disclosed. Both of the skylights can use the skylight dome
disclosed in U.S. Pat. No. 5,896,712 also owned by the same
assignee as is the present invention and also incorporated herein
by reference. These inventions represent advances over the prior
art and one or more of them has found commercial success.
[0003] Briefly, a tubular skylight such as those mentioned above
includes a tube assembly mounted between the roof and ceiling of a
building. The top end of the tube assembly is covered by a
roof-mounted dome or cover, such as the one disclosed in the
above-mentioned '712 patent, while the bottom end of the tube
assembly is covered by a ceiling-mounted diffuser plate. With this
combination, natural light external to the building is directed
through the tube assembly into the interior of the building to
illuminate the interior.
[0004] Tubular skylights use a near specular finish reflective
surface to transport sunlight down the tube from the roof to the
interior ceiling. "Specular" means that reflected direct rays of
sunlight maintain a near parallel beam of light as they reflect
down the tube if the tube sides are parallel and the specular
reflective surface is maintained.
[0005] The present invention understands that sunlight enters the
tube at various incident angles based on time of day/year,
latitude, and tube opening plane location. Despite the fixed
position of the tube, direct beam sunlight reflects down the
perimeter of the tube at approximately the same elevation angle as
it enters the tube. As understood herein, this can result in the
following undesirable outcomes. First, the parallel beam sunlight
can converge at concentrated focal points at various locations down
the tube, resulting in potentially dangerous hot spots that can
cause fires particularly in the presence of combustible materials.
Second, uneven illumination results at the base diffuser of the
tube, because the perimeter path of the light rays in combination
with the focal points can cause partial and non-uniform
illumination of the diffuser. The result is poor illumination
performance and glare from the diffuser. Additionally, the direct
light beams passing through a prism in the diffuser can cause the
separation of the wavelengths and project rainbows into the
interior.
[0006] Accordingly, the present invention makes the following
critical observations. Direct beam sunlight reflected from a
specular surface in the approximate shape of a tube can create hot
spots that are unsafe and that reduce product performance due to
non-uniform illumination. As further understood herein, simply
reducing the specularity of the tube results in reduced light
transmission. Likewise, installing a diffuser above the tube to
address glare and hot spots reduces the total system performance
due to the transmission loss of this extra diffuser and the
increased tube reflections caused by the light spread. Moreover,
attempting to remedy the above-noted shortcomings using a random
patterned reflector results in the light being diffused in a
hemispherical shape that may send greater than 50% of the light
back up the tube, therefore once again reducing performance. With
the above observations in mind, the invention herein is
provided.
SUMMARY OF THE INVENTION
[0007] The interior of a skylight tube is formed with structures
that change sunlight beam angles to prevent the formation of a
focal point, and/or that mix the light to uniformly illuminate the
base diffuser and eliminate glare and color separation, and/or that
control light direction to prevent retro-reflection and excessive
reflections.
[0008] Accordingly, in a first aspect a skylight assembly has a
transparent dome and a skylight shaft substrate extending away from
the dome to convey light entering the dome through the shaft
substrate. Surface irregularities are formed on the shaft
substrate. The surface irregularities can be dimples or
longitudinal corrugations.
[0009] In some implementations the shaft substrate is metal and is
polished to provide a reflective surface without any reflective
film incorporated into the assembly. In other implementations the
shaft substrate is metal and a reflective metal is deposited as by
vapor deposition directly on the inside surface of the shaft
substrate to render the assembly internally reflective without
incorporating an adhesive into the assembly. In yet other
implementations the shaft substrate may be a reflective film with a
metallic substance being vapor-deposited onto the film or with a
reflective multi-layer polymer composite being adhered to the
substrate.
[0010] When the surface irregularities are longitudinal
corrugations, each corrugation defines a midline and opposed edges,
and a first angle is formed between transverse tangents to edges of
first corrugations. Also, a second angle different from the first
angle is formed between transverse tangents to edges of second
corrugations. The first and second corrugations alternate around
the circumference of the shaft substrate, and may be V-shaped or
U-shaped in transverse cross-section.
[0011] When the surface irregularities are plural dimples, each
dimple defines a center and a periphery. A tangent to the periphery
establishes an angle with respect to a tangent to the center of no
more than two degrees.
[0012] In another aspect, a skylight assembly includes a
transparent dome and a skylight shaft substrate extending away from
the dome to convey light entering the dome through the shaft
substrate. Surface irregularities are formed on the shaft
substrate. In this aspect, the shaft substrate is metal, and a
reflective metal is deposited directly on the inside surface of the
shaft substrate to render the assembly internally reflective
without incorporating an adhesive into the assembly.
[0013] In yet another aspect, a skylight assembly includes a
transparent dome and a skylight shaft substrate extending away from
the dome to convey light entering the dome through the shaft
substrate. Surface irregularities are formed on the shaft
substrate. In this aspect, the shaft substrate is metal and is
polished to provide a reflective surface without any reflective
film incorporated into the assembly.
[0014] In still another aspect, a skylight assembly includes a
transparent dome and a skylight shaft substrate extending away from
the dome to convey light entering the dome through the shaft
substrate. Surface irregularities are formed on the shaft
substrate. In this aspect, the shaft substrate is a reflective film
with a metallic substance being vapor-deposited onto the film.
[0015] In another aspect, a skylight assembly includes a
transparent dome and a skylight shaft substrate extending away from
the dome to convey light entering the dome through the shaft
substrate. Surface irregularities are formed on the shaft
substrate. In this aspect, the shaft substrate is a reflective film
including a reflective multi-layer polymer composite.
[0016] The details of the present invention, both as to its
structure and operation, can best be understood in reference to the
accompanying drawings, in which like reference numerals refer to
like parts, and in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a side view in partial cross-section of the
tubular skylight of the present invention;
[0018] FIG. 2 is a perspective view of the present tube with
longitudinal corrugations for reducing focal points;
[0019] FIG. 3 is a side elevational view of the inside of the tube
shown in FIG. 2;
[0020] FIG. 4 is a top plan view of the tube shown in FIG. 2;
[0021] FIG. 5 is a detail of part of the circumference of the tube
in circle "5" of FIG. 4;
[0022] FIG. 6 is a perspective view of an alternate tube with
dimples for reducing focal points;
[0023] FIG. 7 is a top plan view of the tube shown in FIG. 6;
[0024] FIG. 8 is a side elevational view of the tube as seen along
the line 8-8 in FIG. 7; and
[0025] FIG. 9 is a detail of a dimple in circle "9" of FIG. 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026] Referring initially to FIG. 1, a tubular skylight made in
accordance with the present invention is shown, generally
designated 10, for lighting, with natural sunlight, an interior
room 12 having a ceiling dry wall 14 in a building, generally
designated 16. FIG. 1 shows that the building 16 has a roof 18 and
one or more joists 20 that support the roof 18 and ceiling dry wall
14.
[0027] As shown in FIG. 1, the skylight 10 includes a rigid hard
plastic or glass roof-mounted cover 21. The cover 21 is optically
transmissive and preferably is transparent. In one embodiment, the
cover 21 can be the cover disclosed in the above-mentioned '712
patent. Or, the cover 21 can be other suitable covers, such as the
covers marketed under the trade name "Solatube" by the present
assignee.
[0028] The cover 21 can be mounted to the roof 18 by means of a
ring-like metal flashing 22 that is attached to the roof 18 by
means well-known in the art. The metal flashing 22 can be angled as
appropriate for the cant of the roof 18 to engage and hold the
cover 21 in the generally vertically upright orientation shown.
[0029] As further shown in FIG. 1, an internally reflective hollow
shaft assembly, generally designated 24, is connected to the
flashing 22. The cross-section of the assembly 24 can be
cylindrical, rectangular, triangular, etc. Accordingly, while the
word "tube" may be used from time to time herein, it is to be
understood that the principles of the present invention are not to
be limited to a cylinder per se unless otherwise specified.
[0030] The shaft assembly 24 extends to the ceiling 14 of the
interior room 12. Per the present invention, the shaft assembly 24
directs light that enters the shaft assembly 24 downwardly to a
light diffuser assembly, generally designated 26, that is disposed
in the room 12 and that is mounted to the ceiling 14 or to a joist
20 as described in the above-mentioned '593 patent.
[0031] The shaft assembly 24 can be made of a metal such as an
alloy of aluminum or steel, or the shaft assembly 24 can be made of
plastic or other appropriate material. The interior of the shaft
assembly 24 may be rendered reflective by means of, e.g.,
electroplating, anodizing, metalized plastic film coating, or other
suitable means. In one preferred embodiment, the shaft assembly 24
is rendered internally reflective by laminating the inside surface
of the shaft assembly with a multi-ply polymeric film made by
Minnesota Mining and Manufacturing (3M). A single ply of such film
is transparent, but when hundreds of layers are positioned flush
together and then thermally laminated to the interior surface of
the shaft assembly 24, the combination is specularly
reflective.
[0032] Thus, in non-limiting implementations the shaft may be made
of a composite of a metal substrate, e.g., aluminum or steel, with
a reflective film adhered to the shaft using an adhesive. The shaft
substrate can also be made of a polymer with the reflective film
bonded to it.
[0033] Alternatively, if the shaft is metal, the shaft substrate
can be polished to provide a reflective surface or have a highly
reflective metal such as silver or aluminum vapor deposited
directly to its surface without the need for a separate
adhesive.
[0034] In yet other implementations a reflective film itself may be
used as a shaft substrate. In such an implementation, metal is
vapor-deposited onto the film surface. Or, the film can include a
reflective multi-layer polymer composite.
[0035] In one preferred embodiment, the shaft assembly 24 is
established by a single tube. However, as shown in FIG. 1, if
desired, the shaft assembly 24 can include multiple segments, each
one of which is internally reflective in accordance with present
principles. Specifically, the shaft assembly 24 can include an
upper shaft 28 that is engaged with the flashing 22 and that is
covered by the cover 21. Also, the shaft assembly 24 can include an
upper intermediate shaft 30 that is contiguous to the upper shaft
28 and that can be angled relative thereto at an elbow 31 if
desired. Moreover, the shaft assembly 24 can include a lower
intermediate shaft 32 that, if desired, may be slidably engaged
with the upper intermediate shaft 30 for absorbing thermal stresses
in the shaft assembly 24. And, a lower shaft 34 can be contiguous
to the lower intermediate shaft 32 and join the lower intermediate
shaft 32 at an elbow 35, with the bottom of the lower shaft 34
being covered by the diffuser assembly 26. The elbow 35 may be
angled as appropriate for the building 16 such that the shaft
assembly 24 connects the roof-mounted cover 21 to the
ceiling-mounted diffuser assembly 26. It is to be understood that
where appropriate, certain joints between shafts can be
mechanically fastened and covered with tape in accordance with
principles known in the art.
[0036] In any case, the present shaft assembly 24 is formed with
surface irregularities on part or all of its inner surface for
reflecting light in a way that minimizes the chance of hot spots
while nonetheless maximizing light throughput. The surface
irregularities may be those described in the present assignee's
U.S. patent publication no. 2003/0061775, incorporated herein by
reference, or the corrugations or dimples disclosed herein.
[0037] More specifically, FIGS. 2-5 show a hollow shaft 40 that may
be used as any one of the shafts or shaft segments shown in FIG. 1
and that is formed throughout its length and circumference with
linear longitudinal corrugations 42, it being understood that the
corrugations 42 may be formed in only part of the length and/or
circumference of the shaft 40. As shown best in FIG. 5, the
corrugations 42 can have a V-shape in transverse cross-section,
although alternately they may be U-shaped.
[0038] In general, each corrugation can vary in its included angle
from less than one hundred eighty degrees to greater than one
degree, and preferably the included angle is greater than one
hundred twenty degrees to minimize reflections. Also, the angle can
vary around the shaft to provide a greater amount of mixing of the
light before it reaches the base diffuser, as will be made clearer
momentarily in reference to FIG. 5.
[0039] In addition to the controlled light spreading features, the
corrugations 42 also allow easier bending of the substrate, when
metal, to form a cylindrical shaft from a sheet, and to increase
the lateral strength of the shaft 40 due to the increased moment of
inertia this geometry provides. These two features allow easier
assembly of small diameter tubing and the use of reduced caliper
metal due to the increased strength.
[0040] With greater attention to preferred non-limiting details in
FIG. 5, each corrugation 42 defines a midline 44 and opposed edges
46, 48, with adjacent edges of adjacent corrugations joining each
other as shown. While for illustration the midlines 44 in FIG. 5
are defined to be the parts of the corrugations that are radially
inset from the edges, hence establishing concave corrugations, the
skilled artisan will readily appreciate that the convention can be
reversed, i.e., that midlines can be defined to be the radially
outside parts of the corrugations, hence establishing convex
corrugations.
[0041] In any case, FIG. 5 shows that an angle .alpha. is formed
between transverse tangents to the edges 46, 48 of each
corrugation. When the corrugation is V-shaped as shown, the
transverse tangents are simply lines extending in the transverse
dimension from the midline 44 to each edge 46, 48 as shown, i.e.,
the angle .alpha. is the angle of the "V". As further shown in FIG.
5, odd-numbered corrugations can have a first angle .alpha., e.g.,
one hundred twenty degrees, whereas even-numbered corrugations can
form a second angle .alpha., e.g., one hundred twenty five degrees,
with the odd-numbered corrugations alternating around the
circumference of the shaft 40 with the even-numbered corrugations.
This geometry results as shown in an angle of two and a half
degrees being established between the normal 50 to an edge 48 and
the normal 52 to the adjacent midline 44, and an angle of five
degrees being established between the normal 52 to a midline 44 and
the normal 54 to the next successive midline 44.
[0042] Alternatively to corrugations, FIGS. 6-9 show a dimpled
hollow shaft 60 that may be used as any one of the shafts or shaft
segments shown in FIG. 1. Specifically, the shaft 60 is formed
throughout its length and circumference with dimples 62, it being
understood that the dimples 62 may be formed in only part of the
length and/or circumference of the shaft 60.
[0043] A dimple 62 may have any suitable shape, e.g., one of the
myriad of shapes of golf ball dimples, e.g., spherical, elliptical,
parabolic, hyperbolic, etc. In the illustrative non-limiting
embodiment shown best in FIG. 9, each dimple 62 has a concave (or
convex, depending on the perspective, i.e., outside or inside)
saucer-like shape and hence can establish what might be thought of
as the very bottom portion of spherical or parabolic or other bowl
that is curvilinear throughout its surface.
[0044] Accordingly, in the non-limiting implementation shown, each
dimple 62 defines a center 64 and a preferably circular periphery
66. A tangent 68 to the periphery 66 establishes an angle .beta.
with respect to a tangent 70 to the center 64 of no more than two
degrees (to give greater resolution for seeing the angle .beta. in
FIG. 5, the tangent 70 to the center 64 has been offset to the
right of the center 62.) Additionally, the distance in the radial
dimension between the center 64 and periphery 66 preferably is less
than one half inch (<0.5 inches, or less than approximately one
and one-quarter centimeters). By limiting the angle .beta. to less
than two degrees, the loss of low elevation sunlight is prevented.
By limiting the distance in the radial dimension between the center
64 and periphery 66 to less than one-half inch, excessive
reflections are prevented, which could otherwise eventually lead to
sunlight being reflected back up and out of the dome 21 (FIG. 1)
and hence decrease the light throughput of the shaft 60.
[0045] In non-limiting embodiments the corrugations and/or dimples
described above can be formed in any appropriate way. In one
non-limiting example the metal shaft, or the reflective film, or
the adhesive can be formed or patterned with an embossing roller.
In another example the metal shaft, film, or adhesive can be
extruded or coated with the required profile in the extrusion or
coating die. Yet again, the metal shaft, film, or adhesive can be
molded with the required pattern in a mold tool.
[0046] While the particular SKYLIGHT TUBE WITH REFLECTIVE
STRUCTURED SURFACE is herein shown and described in detail, the
invention is to be limited by nothing except the appended
claims.
* * * * *