Abstract:
A system for growing a plant includes an inwardly reflective enclosure and preferably a top. A plurality of LEDs, preferably controlled by a control unit, selectively emit light onto predetermined portions of the plant. The control unit controls the growing conditions inside the enclosure with the use of air vents and air flow, an optional heater, and feedback from light intensity and color sensors. The inwardly reflective enclosure can be formed of inner and outer walls with a reflective film sandwiched in between. If desired, a recycling collar can be used with any of the LEDs to increase the intensity of the light ray. The top cover can be formed of a plurality of panels rotatable about their longitudinal axis between a closed position and open position. In another embodiment, pair of inwardly reflective enclosures share a common, reflective wall with holes. The two enclosures are operated through light and dark cycles so as to exchange oxygen and carbon dioxide alternately with one another

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present patent application claims priority on U.S. provisional application No. 61/989,103, filed on May 6, 2014; on U.S. provisional application No. 62/027,979, filed on Jul. 23, 2014; and on U.S. provisional application No. 62/140,026, filed on Mar. 30, 2015 
     
    
     BACKGROUND 
       [0002]    In recent years, the efficiency of LEDs has improved tremendously. With drastically lower prices, it has become feasible for LEDs to be used as lighting sources for plant growth. Because LEDs can illuminate a plant continuously at reasonable cost, and with a light intensity potentially greater than that of the sun, the rate of growth can be increased beyond natural growth under natural sunlight conditions. It is also possible now to grow plants in winter, when sunlight is minimum, and at night time when it is dark. 
         [0003]    Besides lighting conditions, it is also common for plants to growth best at certain temperatures. Greenhouses are designed such that the temperature is controlled providing the most optimum conditions. It is also known that based on the color of the leaves, the absorption spectrum of the leaves differ based on the type to type of plants. 
       SUMMARY OF THE INVENTION 
       [0004]    This invention discloses a scalable self-contained LED plant growth lighting system integrated with the green house in which the LED are placed inside a housing with reflective inside surfaces. The temperature of the system can be controlled by air vents, which control the removal of heat generated by the LEDs, providing the optimum growth temperature. In addition, the color of the LEDs can be chosen to match the absorption spectrum of the chlorophyll in the leaves. With such enclosed system, CO 2  can be added with minimal loss, further increasing the growth rate of the plant. Such recycling light system also allows illumination of the bottom of the leaves by placing LEDs under the leaves, increasing the area of photosynthesis, further increases the growth rate of the plant. 
         [0005]    More particularly, a system for growing plants includes an inwardly reflective enclosure and preferably a top. Pluralities of LEDs, preferably controlled by a control unit, selectively emit light onto predetermined portions of the plant. The control unit controls the growing conditions inside the enclosure with the use of air vents and air flow, an optional heater, and feedback from light intensity and color sensors. 
         [0006]    The inwardly reflective enclosure can be formed of inner and outer walls with a reflective film sandwiched in between. If desired, a recycling collar can be used with any of the LEDs to increase the intensity of the light ray. The top cover can be formed of a plurality of panels rotatable about their longitudinal axis between a closed position and open position, to control both the admission of light and the flow of air. In another embodiment, pair of inwardly reflective enclosures share a common, reflective wall. The shared wall includes holes to allow oxygen to flow from one chamber to another and allow carbon dioxide to flow from the other chamber into the first chamber. The two enclosures are operated through light and dark cycles so as to exchange oxygen and carbon dioxide alternately with one another. 
         [0007]    Alternatively, the system described above can be operated so that one chamber is a sacrificial chamber, which is provided with dead organic matter, for example lawn clippings, to emit carbon dioxide to the other chamber to speed growth. 
         [0008]    The increase in efficiency also allows higher efficiency of electricity usage, which is a major cost of production. With the lack of energy resources and the need to lower the particulate pollution and CO 2  emission, the increase in efficiency in electricity use will be an important factor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a side, schematic drawing of a plant growth system according to the invention; 
           [0010]      FIG. 2  is side, schematic view of an alternative system; 
           [0011]      FIG. 3  is a side, schematic view of another system according to the invention; 
           [0012]      FIG. 4  is a side, schematic view of another system according to the invention; 
           [0013]      FIG. 5  is a side, schematic view of another system according to the invention; 
           [0014]      FIG. 6  is a side, schematic view of another system according to the invention; 
           [0015]      FIG. 7  is a side, schematic view of another system according to the invention; 
           [0016]      FIG. 8  is a side, schematic view of another system according to the invention; 
           [0017]      FIG. 9  is a side, schematic view of another system according to the invention; 
           [0018]      FIG. 10  is a side, schematic view of the rotatable reflective panels of the  FIG. 9  embodiment in the closed and open positions; 
           [0019]      FIG. 11  is a side, schematic view of another system according to the invention; 
           [0020]      FIG. 12  is a side, schematic view of another system according to the invention; 
           [0021]      FIG. 13  is a side, schematic view of another system according to the invention; 
           [0022]      FIG. 14-20  are perspective views of various alternate shapes for housings used in the system according to the invention; 
           [0023]      FIG. 21  is a side, schematic view of a known system for growing plants; 
           [0024]      FIG. 22  is a perspective, schematic view of another system according to the invention, along with top views of various alternatively shaped housing enclosures; 
           [0025]      FIG. 23  is a perspective, schematic view of the cylindrical housing enclosure of  FIG. 22 , together with various alternate shapes of the sidewall; 
           [0026]      FIG. 26  are side, schematic views of other lighting arrangement for a system according to the invention; 
           [0027]      FIGS. 27-29  are schematic, perspective views of other lighting sources for use with a system according to the invention; 
           [0028]      FIG. 30  is a side, schematic view of another system according to the invention; and 
           [0029]      FIG. 31  is a side, schematic view of another system according to the invention; 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]      FIG. 1  is a schematic diagram of a basic system. In the following discussion of the first embodiment, the plant is represented by a pot  10 , soil  12  in the pot, a stem  14 , branches  16 , and leaves  18 , with the optional fruit left out for simplicity purposes. The recycling lighting system includes an enclosure  20  with reflective inside surfaces  23 , and a preferably removable top cover  24  with air vents  26  passing therethrough. The enclosure includes sides and a bottom portion  33  having air vents  32  to allow air to enter and leave the interior of the enclosure  20 . The upwardly facing surface of the bottom portion  33  also includes an inside reflective surface. Due to the vents  32  and  26 , during certain temperature conditions, air can enter the bottom portion  33  through the air vents  32  in the bottom portion  33  and exit upwardly through the air vents  26  in the top cover  24  to control the temperature inside the enclosure  20 . 
         [0031]    One or more LEDs  30  of one or more colors are mounted on the underside of the top cover  24  so as to shine light on the leaves  18 . Except for the air vents  26  and the LEDs, the remainder of the bottom surface of the top cover  24  is covered with a reflective material. The bottom portion  33  includes an opening  34  through which the stem extends. Although not specifically shown, the bottom portion  33  is configured to be removed and secured around the stem  14  when desired. For example, the bottom portion  33  may include two pieces and be removably secured to the enclosure. When removed, the two pieces pivot or separate relative to one another so that the bottom portion  33  can either be attached around, or removed from, the stem  14 , 
         [0032]    The enclosure  20  may include a CO 2  intake port  36 , a temperature sensor  38 , a heater  40 , an insulation jacket (not shown), a CO 2  sensor  42 , a light intensity sensor  44 , and a color sensor  46  for the leaves. The enclosure  20  can also include a fan for circulating air within the enclosure and moving air in and out of the enclosure. 
         [0033]    While the top cover  24 , when closed, is shown in a fixed position, preferably it is secured to the enclosure  20  as to be movable up and down, allowing the enclosure to lengthen as the plant grows taller. The system also includes a power supply and a control unit  50  which can communicate, preferably wirelessly, with the sensors and heater and control lighting of the LEDs, including turning them on and off, adjusting the intensity, and selecting which color LEDs to illuminate based on the readings from the color sensor  46 . 
         [0034]    In  FIG. 1 , the LEDs  30  are placed below the top cover  24  of the enclosure with light directed downwardly towards the leaves  18 . Part of the light will also be directed toward the reflective side surface  23  of the inside of the enclosure and will reflect back towards the leaves  18 . With high reflective coatings on the surfaces, very little light will be lost and the light will eventually be absorbed by the leaves, in some cases after multiple bounces off of the inside reflective surfaces  23 ,  24 . The efficiency of the system is also assured because the bottom portion  33  of the enclosure does not allow light from the LEDs  30  to illuminate the soil or pot, in which case light energy would be lost. This is especially significant during the initial cycle of growth when the number and size of the leaves  18  are minimal and, in a traditional growth method, a great deal of soil is exposed. 
         [0035]    The enclosure also acts as a greenhouse, trapping the heat generated by the LEDs. Optionally, an insulating jacket (not shown) can be wrapped around the outside of the enclosure  20  to increase the temperature to the desired optimum value. 
         [0036]    In  FIG. 1 , the enclosure is shaped essentially like a stemless wine glass. Alternately, the enclosure  20   a  can be cylindrical as shown in  FIG. 2  with a circular upper lid  24   a  where the LEDs  30  are mounted, which also acts as a heat sink, and a lower cover  30   a  with an aperture  34  for the stem to pass through. As in the case of  FIG. 1 , the lid  24   a  is preferably removable, or at least can open, and also preferably can be positioned at various heights to allow the LEDs to be repositioned as the plant grows. 
         [0037]    The inside walls of the enclosure are made reflective by putting on metal or dichroic coatings  23   a  made by vacuum deposition, open deposition, painting, or any other suitable method. The walls  23   a  can also be made reflective by putting a reflective sheet, such as reflective films made by  3 M, on the inside surfaces. LEDs can also be placed on the lower cover  30   a  and the sidewall  31   a , increasing the intensity of the light, thus increasing the growth rate. 
         [0038]    In another embodiment, the reflective films  51  can be placed inside the gap between two layers  52 ,  54  of a double wall as shown in  FIG. 3 . This provides better protection of the reflective surface. Although not shown, the enclosure  56  in  FIG. 3  also includes a top cover  24   b  to form an enclosed space for the plant. 
         [0039]    The enclosure can be made of glass, plastic, metal, etc. The enclosure can also be molded to reduce production costs. In one embodiment, the enclosure can be made in multiple pieces put together in a clam-shell type of construction which opens and closes to insert or remove the plant. 
         [0040]      FIG. 4  shows the enclosure  20  with a top cover  24  which is mounted inside the sidewall in a manner in which it can be repositioned to move the LEDs  30  to an appropriate height to accommodate the plant as it grows. For example, the top cover  24  can have a friction fit with the inside surface of the enclosure sidewall  31   a . Other mounting systems may also be employed. The top cover  24  can be coupled to a motor (not shown) which in turn is controlled by the control unit  50  of  FIG. 1  to periodically reposition the top cover  24 . Any suitable mounting configuration may be employed to allow the top cover  24  to move vertically. 
         [0041]      FIG. 5  shows another embodiment in which LED arrays  30  are placed, in addition to the top cover, on the sidewalls  31   a  and the bottom cover  33 . This arrangement of LEDs allows the illumination of the leaves from many directions, increasing the growth rate of the plant. 
         [0042]    Referring to  FIG. 6 , during part or all of the growth cycle of a plant, for example, the initial growth period when there are only a few small leaves, a special LED lighting source can be added to the top cover using a recycling light technology developed by Wavien, Inc. Such technology involves the use of a recycling collar  54 . The recycling collar  54  has a curved concave reflective surface which faces the LED  30 , and a central aperture  56  which is positioned relative to the LED  30  in the path  58  of desired direction of the light beam. With the recycling collar  54 , light emitted by the LED  30  in the direction of the light path  58  passes through the aperture  56  and is directed towards one or more of the leaves  18  of the plant. Larger angle light beams strike the interior reflective wall of the collar  54  and are reflected back towards the LED, either directly or indirectly, for recycling. If desired, light emitted from the collar  54  can be directed to pass through a lens  55 . The collar increases the intensity of the light so as be several times higher than the LED emits on its own. The use of such technology further increases the initial growth rate. 
         [0043]    Preferably, each collar  54  is removably secured to the top cover  24  to cover one LED  30 . If desired, the collar  54  may be removably secured to the LED itself. In such a manner, during the young plant&#39;s life, initially all of the LED light is directed by the collar  54  towards the few initial leaves  18  to increase the growth rate. As the plant matures, the collars are removed so that the LED light is directed towards more of the newer leaves. Once the plant is removed, the collar  54  can be reattached to grow the next young plant. 
         [0044]    The absorption spectrum of the leaves can also be determine by the colors it reflector. As there are many colors of the leaves, there will be as many optimum light spectra for optimum growth of various plants. Various quantities of LEDs with various colors can be combined to produce the desired optimum spectrum for any particular. Since each LED, or a group of LEDs, can be controlled independently by the control unit  50 , the various colored LEDs can be connected to a controlled circuit, optionally controlled by computers. Since the color of the leaves change during growth, the color of the LEDs can also be adjusted for optimum growth rate. The control unit  50  thus monitors readings from the color sensor  46  and adjusts the color of the LEDs illuminated accordingly. 
         [0045]    In all of the embodiments, a color sensor unit  46  can be used to detect the color of the leaves and adjust the color of the LED lights accordingly for optimum growth rate. 
         [0046]    The previous descriptions are for a single lighting system placed together with a single plant. The system can be scaled up for high volume production with multiple units placed in an array on shelves in close proximity. In such arrangement, some of the components can be combined into single units lowering the cost of the system. For example, a single power supply can be used to drive multiple units of lighting systems. A single control unit can be used to control multiple lighting systems. Instead of a single plant growing in a single pot, multiple plants can be placed inside a single larger pot. In another embodiment, multiple plants can be grown on land without any pot. 
         [0047]      FIG. 7  shows an embodiment of a lighting system using a single recycling collar  60  and a collimating lens  62 . The collar  60  has a convex reflecting surface, e.g., round, which faces the LED  30 . The collar  60  also as a center opening  64  and the lens  62  is positioned to receive light which exits the recycling collar  60  through the opening. Due to the recycling collar  60 , light rays which are emitted by the LED  30  at an angle greater than a predetermined angle strike the collar reflective surface and are reflected back to the LED for recycling. Lower angle rays exit the opening  64  and strike the collimating lens  62 , which directs such rays toward the leaves  18 . In effect, the collar  60  acts to concentrate the rays so that those striking the leaves  18  have increased brightness to increase the growth rate of the plant. 
         [0048]    In the above embodiments, the soil and the pots are placed away from the lighting system, allowing ease in irrigation. In a similar manner, a large-scale implementation of such system can be done as shown in  FIG. 8 . Multiple plants  68  are spaced at certain distances apart, with their roots soil  12  which is either in pots  10  or in the ground (not shown). The ground surface in the spaces between the plants  68  are covered with reflective materials such that light will be reflected instead of wasted. Again, this is significant when the plants are small with few leaves at the initial stage of growth. A greenhouse  70  is constructed around the plants with all inside surfaces are covered with reflective materials  72 . LED growth lights  30  are then placed inside the reflective material  72  above, below, and on the sides of the plants providing maximum illumination. 
         [0049]    As shown in  FIGS. 9 and 10 , in another embodiment, the enclosure  74  has a ceiling  76  and side walls  78  covered with flat, elongated reflective panels  80 . Each panel  80  is mounted on a pivot  82  so that it can be rotated between an open position  84  and a closed position  86 . In the closed position, the longitudinal edges  88  of the panels  80  preferably overlap or abut one another closely to block, or at least substantially block, outside light from entering the interior of the enclosure  74 . 
         [0050]    In the embodiment of  FIGS. 9 and 10 , during the hours of sunshine, the reflective panels  80  are kept in the open position  84  such that the sunlight can penetrate through the spaces and illuminate the plants. When the sunlight is weak or absent, the reflective panels  80  are rotated into the closed position forming a completely enclosed greenhouse with reflective interior surfaces. The LEDs  30  are then illuminated as the light source. Such implementation allows effective use of sunlight and LED light with optimum growth rates, while saving electricity. The opening and closing of the panels  80 , and turning the LEDs on and off, can be controlled by the control unit  50  using a motor  90  and a light sensor  92 . 
         [0051]    One of the known methods to increase the growth rate is to increase the concentration of carbon dioxide (CO 2 ) during photosynthesis. Farmers with greenhouses would often burn propane to increase the concentration, which is not energy efficient.  FIG. 11  discloses a system and method of increasing the carbon dioxide concentration by using two chambers  100 ,  102 , which are separated from one another by a reflective partition  104  having air passages therethrough. The outside surfaces of the chambers  100 ,  102  are also covered by a reflective wall, and an LED light source L 1  and L 2  is placed in each chamber  100 ,  102 . 
         [0052]    The explanation of the system is simplified by referring only to two plants, P 1  and P 2 . Plant P 1  is placed inside chamber  100 , and plant P 2  is placed in the other chamber  102 . The area of the air passage through the partition  104  will be small compared to the area of the partition such that the light loss will be minimized. If necessary, reflective shades (not shown) can be used to prevent light leakages. 
         [0053]    The light cycling has two phases. In the first phase, the plant P 1  is resting in the dark with lamp L 1  turned off as shown in  FIG. 12 . The plant P 1  will not undergo photosynthesis and will be absorbing oxygen (O 2 ) and releasing carbon dioxide (CO 2 ). In the other chamber  102 , light L 2  is on and P 1  will be absorbing carbon dioxide and releasing oxygen through photosynthesis. The net result is that the plant P 1  supplies extra carbon dioxide to the plant P 2 , and the plant P 2  supplies extra oxygen for P 1 . 
         [0054]    During the second phase, shown in  FIG. 13 , the system is reversed. The light L 1  is on, and the light L 2  is off Plant P 1  supplies oxygen to plant P 2 , and plant P 2  supplies carbon dioxide to plant P 1 . For certain plants, both L 1  and L 2  can be on or off at the same time depending on the optimization of the growth rates. 
         [0055]    This system can be further extended to have sacrificial plants such that the light is always off. If plant P 1  is a sacrificial plant, the light L 1  will remain off, and plant P 1  emits carbon dioxide to help plant P 2  to growth faster. In this case, the light L 1  will remain off at all times and plant P 1  will eventually wither and die producing carbon dioxide during its life. Such sacrificial plant P 1  can be a species different from plant P 2 , or can be fresh plant clippings such that they are still living. For example, cut grass from mowing the lawn can be used as sacrificial plants. The cut grass can be used in place of P 1  and stay in the dark until it withers and dies, while provide carbon dioxide for plant P 2  speeding up the growth. As in other embodiments, the parameters for operating the phases can be programmed into the control unit  50  to turn the lights on and off at the appropriate times. 
         [0056]    The light recycling enclosure  110  can be spherical as shown in  FIG. 14 . In this case, the light will be mixed inside the enclosure without a particular pattern. The enclosure  110   a  can also be cylindrical accommodating taller plants as shown in  FIG. 15 .  FIG. 16  shows a conical enclosure  110   b  for plants with longer stems and with leaves on top. 
         [0057]      FIG. 17  shows a dual parabolic reflector enclosure  110   c  with a focus  112  with certain predetermined light paths as shown. The enclosure  110   c  can be used in any of the embodiments of the invention. 
         [0058]      FIG. 18  shows another dual parabolic reflector enclosure  110   d  with more than one focus  112   d  with light paths as shown.  FIG. 19  shows a truncated dual parabolic reflector enclosure  110   e  with two foci  114 .  FIG. 20  shows another dual parabolic reflector enclosure  110   f  with foci  116  These systems with special reflectors can be used where specific light patterns are desired for certain plants with certain leave/stem shapes, providing further optimization for increased growth rates. 
         [0059]      FIG. 21  shows a typical plant growth system using a light source  120  at the top, with a plant  68  in a container or pot  10 . This system is simple, but not very efficient in the use of light and available leaf surfaces for photo-synthesis. 
         [0060]    To overcome such deficiencies,  FIG. 22  shows a system with a reflective enclosure  122 , with an optional top  124 , a bottom  126  and an optional reflective coating  128  on the enclosure  122 . All of the light generated by the LEDs (not shown) will be confined to the inside of the enclosure  122 , increasing the efficiency of the system. The enclosure can be round, square, hexagonal, octagonal, or any other shape. 
         [0061]      FIG. 23  shows other embodiments of the reflective sidewall  129  of the enclosure  130  in which the side wall can be straight  132 , zigzag  134 , curved  136 , or any other shape to provide more structure to the enclosure. The sidewall shape may provide certain optical function to be described later. 
         [0062]      FIG. 24  shows addition of spot lights  138  above and to the sides of the center of the plant  68 . The spotlights  138  are preferably used during the early growth stage of the plant in which there are only a few small leaves. Light rays  140  from the spotlights  138  are thus focused on the initial leaves of the plant  68 . In this embodiment, the LEDs (not shown) are preferably off during the early growth stage since their light would largely be unused, lowering the efficiency. 
         [0063]      FIG. 25  shows another embodiment with zigzag side walls  134  having reflective surfaces. The sections alternate between horizontal and angled as shown. The light source can be placed at the corners as shown such that the light rays  142  will be directing downward towards the plant  68 . Having light directing upward may cause ill effects to the plant and will not be efficient in photosynthesis. 
         [0064]    Alternately, as shown in  FIG. 26 , the enclosure  144  is square in cross-section. Each of the LED light sources  30  includes a linear heat sink with circuit board populated with one or more LEDs  30  which extend preferably from the top cover  24  of the enclosure  144 . Depending on the type of plants, various colored LEDs can be used including white, red, green, blue, and other custom colors. One or more LEDs and one or more colors can be used at the same time.  FIG. 26  shows an optional top where extra light from LEDs can be added when desired. 
         [0065]      FIG. 27  shows examples of three types of light wands, rectangular in cross-section  150   a , round in cross-section  150   b , and triangular in cross-section  150   c , which can be added inside any of the reflective enclosures, e.g.,  20 , when more light is desired. This is especially useful when the plant grows with dense leaves where the light from the top or from the side cannot reach these leaves. This will decrease the efficiency and growth rate of the plant. One or more of these light wands can be inserted through openings on the side of the enclosure and can be inserted between the leaves illuminating the leaves that would otherwise be in the dark. The light wand can have a cross-section of being square, rectangular, round, triangular, or other convenience shapes. The surfaces can be all bright, partially bright, or partially dark. For example, for the rectangular cross-section  150   a  as show, the top surface  152  can be dark so that it does not shine on the bottom of the leaves and the bottom surface  154  is bright so that it illuminates the top of the leaves promoting photosynthesis as shown in  FIG. 28 . To provide the light, LEDs can be mounted on one side of the light wand such that there will be no light at the top and light output is from the bottom only. Optionally, the top  152  can be painted black or covered with opaque covers. 
         [0066]    In another embodiment, the light wand  156  can be end-lit in which the LEDs  30  are placed at the end of the light wand, which could be outside the enclosure for better heat sinking. The light wand will be made with diffusive materials or structured scattering surfaces similar to the system used in back lights for LCD panels. The top side can be made reflective so that all the light will be directed toward the bottom. 
         [0067]    In another embodiment as shown in  FIG. 29 , the LEDs  30  can be placed along the length of the light wand  160  for edge lighting the diffusive material of which the wand  160  is made. The end-lit system can also be applied to a round light wand  162  with diffusive materials or surfaces as shown. The LEDs  30  input light to one end of the diffusive material wand  160  and  162 . Preferably the opposite end has a reflective material. In the case of wand  160 , preferably the top, the sides, and the end opposite to end containing the LEDs include a reflective material so that all of the diffused light comes out through the bottom surface. In the example of wand  162 , the diffusive material of the light wand is uncovered except for the end opposite to the LEDs. 
         [0068]      FIG. 30  shows the schematic diagram of a system in which one or more light wands  170  of the types described above are inserted through the enclosure wall for illuminating the top of the leaves. 
         [0069]    Referring to  FIG. 31 , light wands  170  can be used to illuminate the inside of a leafy vegetable such as lettuce  172 . Normally, for these kinds of vegetables, the growth of the leaves is from the inside out such that as the vegetable grows, the sunlight will be absorbed mainly by the outer leaves in which photosynthesis occurs. As a result, the natural reaction of the vegetable is such that the outer leaves are greener than the inner leaves. As we all know, the inside leaves of a lettuce are usually whitish and are not as green as the outer leaves. Using light wands as shown in  FIG. 31 , the inner leaves are also illuminated providing photosynthesis, and it is natural that the inner leaves will also be green, providing more green nutrition for the same vegetable.