Note: Descriptions are shown in the official language in which they were submitted.
MODULAR LIGHTING FOR HORTICULTURAL APPLICATIONS
TECHNICAL FIELD
[0001] The present disclosure relates to lighting systems, and more
particularly to lighting
systems for horticultural applications.
BACKGROUND
[0002] Indoor horticultural applications often require the use of artificial
light as a substitute
for, or a supplement to, natural lighting in order to promote the growth of
the plants being
cultivated.
SUMMARY
[0003] The present disclosure describes a highly modular light fixture for
horticultural
applications. The modular nature of the design facilitates upgradeability and
serviceability.
[0004] In one embodiment, the light fixture simultaneously provides both UVA
and UVB
light. In particular embodiments, the light fixture system may additionally
provide visible
light including royal blue light and deep red light.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] These and other features will become more apparent from the following
description in
which reference is made to the appended drawings wherein:
FIGURE 1 is a top perspective view of an illustrative light fixture according
to an aspect of
the present disclosure;
FIGURE 2 is a bottom perspective view of the light fixture of Figure 1;
FIGURE 3 is a first end elevation view of the light fixture of Figure 1;
FIGURE 4 is a first side elevation view of the light fixture of Figure 1;
FIGURE 5 is a second end elevation view of the light fixture of Figure 1;
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FIGURE 6 is a second side elevation of the light fixture of Figure 1;
FIGURE 7 is a top plan view of the light fixture of Figure 1;
FIGURE 8 is a bottom plan view of the light fixture of Figure 1;
FIGURE 9 is a cut-away perspective view of the light fixture of Figure 1;
FIGURE 9A is a cross-sectional view of the light fixture of Figure 1, taken
along the line 9A-
9A in Figure 4; and
FIGURE 10 is an exploded view of a portion of the light fixture of Figure 1.
DETAILED DESCRIPTION
[0006] Reference is now made to Figures 1 to 10, in which an illustrative
light fixture is
indicated generally by reference 100. The light fixture 100 may be of any
desired length,
typically from 2 feet to 8 feet in length, but may be longer or shorter.
[0007] As best seen in Figures 2, 8 and 9 to 10, the light fixture 100
comprises an elongate
chassis 102 having end caps 104 disposed at opposite ends thereof, and carries
a plurality of
light emitting diodes (LEDs) including LEDs 106A that emit light substantially
restricted to
the ultraviolet A (UVA) portion of the spectrum (referred to as "UVA LEDs")
and LEDs
106B that emit light substantially restricted to the ultraviolet B (UVB)
portion of the spectrum
(referred to as "UVB LEDs"). In the illustrated embodiment the light fixture
100 also carries
LEDs 106C that emit light substantially restricted to the visible spectrum
(referred to herein
as "visible light LEDs)". Light fixtures according to the present disclosure
may include UVB
LEDs in combination with only UVA LEDs, or UVB LEDs in combination with only
visible
light LEDs. In preferred embodiments, however, the light fixtures include UVB
LEDs in
combination with both UVA LEDs and visible light LEDs, as described further
below.
[0008] The LEDs 106A, 106B, 106C are mounted to carriers, which are in turn
releasably
secured to the chassis 102. In the illustrated embodiment, the UVA LEDs 106A
and the
visible light LEDs 106C are mounted on different carriers than the carriers on
which the UVB
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LEDs 106B are mounted. More particularly, in the illustrated embodiment the
UVA LEDs
106A and the visible light LEDs 106C are mounted on a first set of LED
carriers 108 and the
UVB LEDs are mounted on a second set of LED carriers 110. In the illustrated
embodiment,
the LED carriers are printed circuit boards (PCBs) to which the LEDs 106A,
106B, 106C are
soldered, and on which are disposed other components such as controllers, etc.
as well as the
relevant electrical connectors. As best seen in Figures 9A and 10, the LED
carriers 108, 110
have through-holes 116 which align with threaded holes 118 in the chassis 102
so that the
LED carriers 108, 110 can be releasably mounted to the chassis 102 by way of
screws, bolts
or the like. This is merely one illustrative mounting method, and clips,
magnetic mounting,
tongue-and-groove, or other suitable techniques may also be used to mount LED
carriers to
the chassis. Releasable mounting of the LED carriers 108, 110 to the chassis
102 allows for
the replacement of individual LED carriers in case of malfunction, or for
upgrading to newer
technology, without having to replace the entire light fixture 100 or take the
light fixture 100
out of service.
[0009] As noted above, in the illustrated embodiment the UVA LEDs 106A and the
visible
light LEDs 106C are mounted on a first set of LED carriers 108 and the UVB
LEDs 106B are
mounted on a second set of LED carriers 110. Thus, the UVB LEDs 106B are
mounted on
different LED carriers 110 than the carriers 108 on which the UVA LEDs 106A
and the
visible light LEDs 106C are mounted. It may be preferable to mount the UVB
LEDs on
different carriers than the carriers used to mount the UVA LEDs and/or the
visible light LEDs
because, at time of writing, UVB LEDs are typically significantly more costly
than UVA
LEDs and visible light LEDs. The separate mounting allows the second set of
LED carriers
110 to which the UVB LEDs 106B are mounted to be retained in the light fixture
100 if any
of the first set of LED carriers 108 are to be replaced (e.g. due to
malfunction or for
upgrading). This may thereby reduce the replacement cost (since replacement of
the UVA
LEDs and/or the visible light LEDs need not entail replacement of the UVB
LEDs, which are
mounted on different LED carriers).
[0010] In the illustrated embodiment, two parallel, adjacent compartments 120,
122 are
formed in and extend along the length of the chassis 102. A first one of the
compartments
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120 receives the first set of LED carriers 108 (to which the UVA LEDs 106A and
the visible
light LEDs 106C are mounted) and a second one of the compartments 122 receives
the second
set of LED carriers 110 (to which the UVB LEDs 106B are mounted). A divider
wall 124
extends along the length of the chassis 102 to separate the two compartments
120, 122. Thus,
the UVA LEDs 106A and the visible light LEDs 106C will be disposed in the
first
compartment 120, and the UVB LEDs 106B will be disposed in the second
compartment 122.
Typically, the compartments 120, 122 will be enclosed by releasably mounted
optical covers
spaced from the LED carriers 108, 110; the optical covers are not shown in the
drawings for
simplicity of illustration. The term "optical", as used in this context,
merely requires the
cover be substantially transmissive for the light of the LEDs in the
compartment enclosed by
that cover transmission, and does not require (or preclude) any refractive
function. Thus, the
optical cover for the first compartment 120 (in which the UVA LEDs 106A and
the visible
light LEDs 106C are disposed) will be substantially transmissive for at least
UVA and visible
light, and the optical cover for the second compartment 122 (in which the UVB
LEDs 106B
are disposed) will be substantially transmissive for at least UVB light. Many
less expensive
materials that are substantially transmissive for UVA and/or visible light
will filter or obstruct
UVB light (some plastic and glass materials can block up to 95% of the most
effective
portions of the UVB range). However, materials that are substantially
transmissive for UVB
light, such as quartz crystalline material, are typically more costly. Thus,
the use of two
compartments 120, 122 can reduce the amount of UVB transmissive material
required (since
only the optical cover for the second compartment 122 needs to be made of such
material),
which may in turn reduce manufacturing costs. The optical covers can be
received in
longitudinally extending slots 128 (see Figures 9 and 9A) formed in the
chassis 102; other
techniques may also be used.
[0011] In the illustrated embodiment, each set of LED carriers 108, 110
comprises a plurality
of LED carriers 108, 110 arranged end-to-end, as best seen in Figures 8 and
10. Thus, a
plurality of the first LED carriers 108 (to which the UVA LEDs 106A and the
visible light
LEDs 106C are mounted) are arranged end-to-end in the first compartment 120
and a plurality
of the second LED carriers 110 (to which the UVB LEDs 106B are mounted) are
arranged
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end-to-end in the second compartment 122. Although it is also contemplated
that each set of
LED carriers may consist of a single (longer) LED carrier, the use of a
plurality of smaller
LED carriers arranged end-to-end in a segmented/modular arrangement allows for
replacement of individual LED carriers (e.g. in the event that some LEDs fail,
or for
upgrading on a piecemeal basis) while leaving other LED carriers in place.
Clips 126 (see
Figures 8 and 10) may be fastened to the chassis 102 by way of the threaded
holes 118 therein
at the physical junctions of the ends of longitudinally adjacent LED carriers
108, 110.
[0012] As shown in Figures 9 and 9A, in the illustrated embodiment the chassis
102 is shaped
so that it includes wiring channels 134 extending along the sides of the
chassis 102 to
accommodate electrical wiring (not shown) connecting the LED carriers 108, 110
to power
and control systems (not shown). As best seen in Figure 9A, a plurality of
wiring conduits
136 are formed in the chassis 102 at intervals along its length and extend
between the
compartments 120, 122 and the wiring channels 134 so that wires (not shown)
can run from
the compartments 120, 122 into the wiring channels 134. Releasable wiring
access flaps 138
extend along the length of the chassis 102 to cover the wiring channels 134;
the wiring access
flaps 138 can be moved to provide access to the wiring channels 134 (e.g. to
change the
wiring when removing or installing the LED carriers 108, 110) and then
replaced into the
covering configuration. The wiring access flaps 138 are preferably pivotally
mounted on the
chassis 102 so that they can pivot along a pivot axis parallel to the
longitudinal direction of
the chassis 102, biased (e.g. by a spring or other biasing member; not shown)
into an open
configuration but retained in a closed (covering) configuration by an elongate
catch 140
running along its length and which forms a releasable interference fit with a
corresponding
elongate lip 142 running along the length of the chassis 102. This is merely
one illustrative
implementation, and other implementations are also envisioned.
[0013] As noted above, the illustrative light fixture 100 has end caps 104
disposed at each
longitudinal end thereof. As best seen in Figure 10, the end caps 104 each
comprise a
baseplate 152 secured (e.g. bolted) to the chassis 102, a hollow riser 154
extending outwardly
from the baseplate 152 opposite the chassis 102, and a cover 156 secured to
the riser 154
opposite the chassis 102. For example, bolts may pass through aligned
apertures in the cover
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156, riser 154 and baseplate 152 into threaded apertures at the ends of the
chassis 102.
Mounting apertures 158 are provided at the four outwardly extending corners of
each
baseplate 152 to facilitate mounting of the light fixture 100. Of note, the
light fixture 100
may be arranged horizontally or vertically. For example, the light fixture 100
may be
arranged vertically to provide light to plants growing in the apparatus taught
by U.S.
Provisional Patent Application No. 62/653,435 filed on April 5, 2018, the
teachings of which
are hereby incorporated by reference.
[0014] Optionally, a plurality of instances of the light fixture 100 may be
connected together
in end-to-end relationship. As shown in Figure 10, the baseplate 152 is
provided with wiring
to ports 160 positioned in registration with the wiring channels 134 on the
chassis 102 to permit
electrical wiring (not shown) to pass from one light fixture 100 to the next.
In embodiments
in which a plurality of instances of the light fixture 100 are connected
together end-to-end, the
cover 156 may be omitted between adjacent light fixtures 100, and a single
shared riser 154
may separate the baseplates 152 of adjacent light fixtures 100. Alternatively,
both the cover
156 and the riser 154 may be omitted between adjacent light fixtures 100, and
the adjacent
light fixtures 100 may share a common baseplate 152.
[0015] In the illustrated embodiment, the chassis 102 is of monolithic
construction, and may
be formed, for example by extrusion. The chassis 102 is provided with a
plurality of
longitudinally extending, outwardly projecting, spaced-apart cooling fins 162,
and is formed
from a material having a suitable thermal coefficient so that the chassis 102
will function as a
heat sink for the LED carriers 108, 110. The chassis 102 may be a passive heat
sink, where
cooling is achieved be exposure of the cooling fins 162 to ambient air, or may
be actively
cooled. For example, a longitudinally extending cover (not shown) may be
placed on the
chassis 102 so as to enclose the cooling fins 162 within a cooling passage,
and air or other
coolant may be blown through the cooling passage. Other cooling arrangements
are also
contemplated.
[0016] Thus, there has been described herein a single light fixture providing,
by way of
LEDs, UVB light in combination with at least one of visible light and UVA
light, and
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preferably both visible light and UVA light. In preferred embodiments, the
light fixture has
UVB LEDs in one compartment and at least one of visible light LEDs and UVA
LEDs in
another, different compartment.
[0017] The light fixtures described herein may be used in a wide range of
horticultural
applications, particularly in indoor growing operations where the light
fixtures substantially
substitute for natural light. The light fixtures can be used to grow a wide
range of plants,
including decorative plants, crop plants, herbs, as well as medicinal plants.
Only in
jurisdictions where it is entirely lawful to do so, and only where all
required permissions,
permits and the like have been obtained and all other legal requirements have
been fully
to complied with, the light fixtures described herein may be used in the
cultivation of cannabis
plants.
[0018] Certain wavelengths of UV light are particularly effective in
cultivating cannabis
plants. A wavelength between 280-290 nm is the most efficient UVB wavelength
range for
stressing the plant (photon efficiency), resulting in elevated cannabinoids,
terpenoids and
other secondary metabolites. A particularly preferred wavelength for UVB is
285 nm,
because wavelengths between 290-300 nm require significantly more
power/exposure than
285 nm; the benefit of the cannabis stress response between 280 nm and 290 nm
is
significantly stronger than between 290 nm and 300 nm. Providing UVB at 285 nm
elevates
secondary metabolites and also provides reduction or elimination of certain
molds and control
of certain pests. For UVA, a wavelength of 365 nm is preferred as it helps
further elevate
terpenes.
[0019] Moreover, a further increase in cannabinoids and terpenoids occurs when
the 285 nm
UVA and 365 nm wavelengths are used together. This results in stronger
flavours, colours,
textures and aromas. Thus, 285 nm UVB and 365 nm UVA have an entourage effect
on
secondary metabolite production when used together. Accordingly, in preferred
embodiments
a method of cannabis cultivation is practiced in which the cannabis plants are
simultaneously
exposed to artificial UVA and UVB light from LEDs, wherein the UVB LEDs emit
at about
285 nm and the UVA LEDs emit at about 365 nm. Without being limited by theory,
this
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combination is believed to be particularly and specifically advantageous in
that it is believed
to aid in plants' receptiveness to photons. Thus, in one preferred
implementation, the UVB
LEDs 106B emit at about 285 nm and the UVA LEDs 106A emit at about 365 nm.
[0020] Illustrative values for photosynthetic photon flux density, power
density and fluence
angles for UVA and UVB light are provided below. In this regard,
"photosynthetic photon
flux density" (PPFD) measures, in micromoles per second per square meter
(p.Mol/s/m2), the
number of photosynthetically active photons that fall on a given surface each
second.
UVA (365 nm) UVB (285 nm)
PPFD: 32 [tMol/s/m2 0.5 ttMol/s/m2
Power Density: 10.5 W/m2 0.21 W/m2
Fluence Angle: 120 125
[0021] Also, for the UVB wavelength at 285 nm, a preferred minimum fluence
rate is about
0.1 mol/m2*s as, without being limited by theory, a fluence rate at or above
this level is
believed to stimulate the UVR8 pathway which is the main secondary metabolite
pathway.
[0022] Optionally, the UVA and UVB light can be combined with artificial
visible light,
preferably from LEDs, such as the visible light LEDs 106C. In one preferred
implementation,
this artificial visible light includes blue light at about 450 nm (royal blue)
and red light at
about 660 nm (deep red). The blue light and the red light may be provided in
isolation, or as
part of light spanning a spectrum that includes blue light at about 450 nm and
red light at
about 660 nm, for example cool white light (5700K). In certain embodiments,
where blue
light and red light are provided in isolation, a combined PPFD of 1050
[tMol/s/m2 is
preferred, and a fluence angle of 120 degrees is also preferred. In some
embodiments, where
visible light spanning a spectrum that includes blue light at about 450 nm and
red light at
about 660 nm is used, a combined PPFD of 950 p.Mol/s/m2 is preferred and a
fluence angle of
170 degrees is also preferred. Optionally, IR light, for example at about 730
nm, may also be
used with the blue light and the red light.
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[0023] Multi-channel control with dimming can be provided to generate
specifically tailored
light recipes, depending on the plant being cultivated and the desired
characteristics.
[0024] Certain illustrative embodiments have been described by way of example.
It will be
apparent to persons skilled in the art that a number of variations and
modifications can be
made without departing from the scope of the claims.
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