CA3057913A1 - Modular lighting for horticultural applications - Google Patents

Abstract

The present disclosure describes a highly modular light fixture for horticultural applications. The modular nature of the design facilitates upgradeability and serviceability. A
single light fixture can provide, by way of LEDs, UVB light in combination with at least one of visible light, including royal blue light and deep red light, and UVA light, and 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. 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.

Description

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;

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

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 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 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 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 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 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.

[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.

Claims

WHAT IS CLAIMED IS:

1. Anything substantially as herein shown or described.