Abstract:
Disclosed herein is an apparatus and method for providing light to grow a plant. An LED array comprises blue light in a band between about 350 nm and 550 nm, red light in a band at about 630 nm and dark red light in a band at about 660 nm. An input device is provided for interrupting the dark red band at 660 nm in order to continue to provide light the plant while the plant continues to flower.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of and priority to prior filed provisional application Ser. No. 61/796,978, filed Nov. 27, 2012, the contents of which are incorporated herein by reference in their entirety. 
    
    
     FIELD OF TECHNOLOGY 
     An improved grow light for a plant using light emitting diodes (LEDs) and more particularly, an improved grow light and method of growing a plant by using light emitting diodes (LEDs). 
     BACKGROUND 
     Plants use photosynthesis to convert water and carbon dioxide to create organic compounds such as cellulose or glucose. It is well-established that artificial lights can be substituted for natural sunlight. In addition to conventional incandescent lights, High Intensity Discharge (HID) lamps, such as Metal Halide (MH) and High Pressure Sodium (HPS), have been used to grow plants. Fluorescent lamps are another example of artificial illumination used to grow plants. Some plant growers desire the ability to control the amount of light provided to the plant. HID and fluorescent lamps require an electronic ballast for operation, which makes controlling the light intensity a challenge. 
     Light emitting diodes (LEDs) are new a lighting technology in the grow light industry. LEDs emit light at specific wavelength bands depending upon the type of diode. Because of this narrow wavelength band a white LED is actually comprised of a mix of different color LEDs to create the white light. The intensity of an LED may be controlled as well. Therefore LEDs may be dimmed. 
     Like any other industry, the agricultural industry seeks to increase production and lower operating costs of its products. Generally, plants exposed to more blue light tend to grow stouter and with broader leads. Plants exposed to more red light tend to grow faster and taller but with thinner stems and smaller leaves. 
     Research has determined that the 660 nm wavelength is crucial to trigger flowering in a plant. In some plant species the 660 nm wavelength must not be present longer than 12 hours per day in order for the plant to flower and to continue to flower. The solution has been to provide illumination for less than 12 hours per day. 
     An exemplary embodiment may overcome these problems and provide a grow light where the 660 nm frequency band may be turned off. 
     SUMMARY 
     An apparatus for providing light to grow a plant comprises an LED array emitting blue light between about 350 nm and 500 nm, red light at about 630 nm and red light at about 660 nm. An input device for producing a 600_nm_ON command and a 660_nm_OFF command is in communication with a controller. The controller is in communication with the LED array and the input device. The controller responds to the 660_nm_ON command by causing the array to emit blue light between about 350 nm and 500 nm, red light at about 630 nm and a red light at about 660 nm and the controller responds to a 660_nm_OFF command by causing the array to emit blue light between about 350 nm and 500 nm and red light at about 630 nm. Additionally the LED array may include infrared light at 740 nm. The input device may also include a command to the controller to cause an increase or decrease in the intensity in any or all of the blue light, the 630 nm red light and the 660 nm red light. 
     In another embodiment the input device may execute a command to the controller to cause an increase or decrease to the intensity of the blue light with respect to the intensity of the 630 nm red light and the intensity of the 660 nm red light to be a ratio. 
     In another embodiment a grow light comprises an LED array for emitting blue light at a band between about 350 nm and 500 nm, red light at a band at about 630 nm and red light at a band at about 660 nm. At least one input device selectively controls the intensity of at least one light band. The controller is in communication with the LED array and the input device were the controller responds to a signal from the input device to command the array to change from a first state where the array emits light comprising a 660 nm band to a second state where the array emits light that does not comprise a 660 nm band. The LED array of the grow light may also include infrared light at a band at about 740 nm. 
     A method of providing light to a plant comprises providing an LED array adapted to emit blue light at a band between about 530 nm and 500 nm, red light at a band at about 630 nm and red light at a band at about 660 nm. The method further comprises conducting electrical power to the LED array to emit blue light at a band between about 350 nm and 500 nm, red light at a band at about 630 nm and red light and at a band about 660 nm and interrupting electrical power to the LEDs adapted to emit a 660 nm band within the LED array. 
     Further objects, features and advantages of the disclosed embodiments will become apparent to those skilled in the art from analysis of the following written description, the accompanying drawings and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an embodiment of a grow light comprising an LED array. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Traditionally agriculture has been performed under natural sunlight. Green plants use little light in the yellow and green part of the spectrum. Green plants reflect most of the yellow and green light which is why they appear green. Green plants primarily use blue light, which consists of light between 350 nm and 500 nm and red light, which is in the regions of 630 nm and 660 nm, during photosynthesis. There is some debate about what proportion of red to blue light is optimal for plant growth. NASA has indicated that the ratio may be 3 to 4:1. Accordingly, independent adjustment of the red and blue bands would provide advantages to growers in the area of power consumption and growth optimization. 
     With initial reference to  FIG. 1 , a block diagram of an embodiment of a grow light  10  comprising an LED array  12  is shown. The LED array  12  comprises blue LEDs  14  and red LEDs  16 . The red LEDs  16  include red LEDs having a wavelength of about 630 nm and dark red LEDs having a wavelength of about 660 nm. Although not shown, the LED array  12  may be further comprised of an infrared LED having a wavelength of about 740 nm. 
     A controller  20  is in communication with the LED array  12  and an input device  30 . In one embodiment input device  30  includes blue control input  32  red control input  34  and dark red control input  36 . The blue control input  32  governs the blue light at a band between about 350 nm and 500 nm and modulates the power supplied to the blue LEDs  14  between 0% and 100%. The red control input  34  governs the red light band at about 630 nm and modulates the power supplied to the red LEDs  16  between 0% and 100%. The dark red control input  36  governs the dark red light band at about 660 nm and modulates the power supplied to the dark red LEDs  16  between 0% and 100%. 
     The input device  30  may be user selectable and the control inputs  32 - 36  may be controlled by manual knobs or by pulse width modulation. The timing of the power supplied to the LEDs may also be electronically controlled, for example by a timer or a timing circuit. 
     A power supply  18  provides electrical power to the controller  20 . Signals from the input device  30  govern how much power is supplied to the LEDs  16 ,  18  within the array  12 . 
     In one embodiement an apparatus  10  provides light to grow a plant, comprising an LED array  12  for emitting blue light between about 350 nm and 500 nm, red light at about 630 nm and red light at about 660 nm. An input device  30  produces a 660_nm_ON command and a 660_nm_OFF command. The 660 nm ON command and a 660 nm OFF command modulate the dark red 660 nm band on or off, respectively. 
     A controller  20  is in communication with the LED array  12  and the input device  30 . The controller responds to the 660_nm_ON command by causing the array  12  to emit blue light between about 350 nm and 500 nm, red light at about 630 nm and red light, at about 660 nm. The controller  20  responds to the 660_nm_OFF command by causing the array  12  to emit blue light between about 350 nm and 500 nm and red light at about 630 nm, meaning the 660 nm red light is off. The LED array  12  may include infrared light at 740 nm. The input device  30  may further includes a command to the controller  20  to cause an increase or decrease to the intensity of said blue light. The input device  30  may further include a command to the controller  20  to cause an increase or decrease to the intensity of the 630 nm red light. The input device  30  further includes a command to the controller  20  to cause an increase or decrease to the intensity of said 660 nm red light. The input device  30  further includes a command to the controller  20  to cause an increase or decrease to the intensity of said 740 nm infrared light. 
     The input device  30  further includes a control input to execute a command to the controller  20  to cause an increase or decrease to the intensity of the blue light, an increase or decrease to the intensity of the 630 nm red light, an increase or decrease to the intensity of 660 nm red light, and an increase or decrease to the intensity of said of the 740 nm infrared light. 
     The input device  20  further includes a command to the controller  30  to cause the intensity of the blue light with respect to the intensity of the 630 nm red light and the intensity of the 660 nm red light to be a ratio. 
     In one embodiment, the grow light  10  comprises an LED array  12  for emitting blue light at a band between about 350 nm and 500 nm, red light at a band at about 630 nm and red light at a band at about 660 nm. The controller  20  is in communication with the LED array  12  and input device  30 . The input device  30  selectively controls the intensity of at least one light band. The controller  20  responds to a signal from the input device  30  to command the array  12  to change from a first state where the array  12  emits light comprising a 660 nm band to a second state where the array  12  emits light that does not comprise a 660 nm band. In one embodiment, the grow light  10  comprises array  12  that includes infrared light at a band at about 740 nm. 
     The grow light  10  comprises an device  30  includes a signal to command an increase or decrease to the intensity of the blue light band. In still another alternative embodiment, the input device  30  includes a signal to command an increase or decrease to the intensity of the 630 nm red light band. In still another alternative embodiment, input device  30  includes a signal to command an increase or decrease to the intensity of the 740 nm infrared light band. In still another alternative embodiment, input device  30  includes a signal to command an increase or decrease to the intensity of the blue light band, an increase or decrease to the intensity of the 630 nm red light band, an increase or decrease to the intensity of the 660 nm red light band, and an increase or decrease to the intensity of the 740 nm infrared light band. In still another alternative embodiment, input device  30  further includes a signal to command the intensity of the blue light band with respect to the intensity of the 630 nm red light band and the intensity of the 660 nm red light band to be a ratio. 
     In operation, the grow light  10  provides light to a plant by the LED Array  12  that emits blue light at a band between about 350 nm and 500 nm, red light at band at about 630 nm and red light at a band at about 660 nm. The power supply  18  conducts electrical power to the controller  20 , which receives signals from the input device  30  to command the LED array  12  to emit blue light at a band between about 350 nm and 500 nm, red light at band at about 630 nm and red light at a band at about 660 nm. The input device  30  produces a command for interrupting electrical power to the LEDs  16  that emit a 660 nm band within the LED array  12 . In one operational embodiment, the LED array  12  emit infrared light at a 740 nm band. 
     The input device  30  is capable of modulating the electrical power to the array  12  to increase or decrease the intensity of the blue light band, increase or decrease to the intensity of the 630 nm red light band, increase or decrease to the intensity of the 660 nm red light and, and an increase or decrease the intensity of the 740 nm infrared light band. The input device  30  may command the controller  20  to interrupt electrical power to the LEDs  16  to turn off the 660 nm band within the LED array  12  for more than 12 hours out of a 24 hour period. 
     The foregoing discussion discloses and describes the preferred structure and control system for the present embodiment. However, one skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims, that various changes, modifications and variations can be made therein without departing from the true spirit fair scope of the embodiment.