LIGHT SOURCES ADAPTED TO SPECTRAL SENSITIVITY OF PLANTS

• US 20150216130A1
• Filed: 04/17/2015
• Published: 08/06/2015
• Est. Priority Date: 07/10/2012
• Status: Active Grant

• Current Assignee: Signify North America Corporation (Signify N.V.)
• Original Assignee: Once Innovations Inc. (Signify N.V.)
• Inventors: Grajcar, Zdenko, Payne, Kevin
• Granted Patent: US 10,028,448 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A01G 7/045 with electric lighting
• CPC Class Codes: A01G 9/249 Lighting means with special arrangements for promoting growth A01G7/045
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: Y02P 60/14 Measures for saving energy, e.g. in green houses

Abstract

A method of stimulating plant growth in a controlled environment that includes providing a lighting assembly having a network of lighting elements such as light emitting diodes (LEDs) that provide light at a color tailored for an individual plant. The lighting assembly is positioned adjacent a plant such that the light produced is received by the plant. The lighting assembly additionally has a control assembly that includes driving circuitry that modulates the lighting elements to controllably provide predetermined periods of light and dark to stimulate continuous growth of the plant.

Claims

1. A method of enhancing plant growth steps comprising:

producing a light output at a wavelength that is within 20 nm of a peak absorption of a predetermined pigment of a plant with at least one lighting element;

positioning the lighting element adjacent the plant such that the light output produced is received by the plant; and

modulating the light output to create predetermined periods of light and dark for the predetermined pigment of the plant to enhance growth of the plants.

2. The method of claim 1 further comprising the steps of:

producing a second light output at a second wavelength that is within 20 nm of a peak absorption of a second predetermined pigment of a plant with a second lighting element; and

modulating the second light output simultaneously with the modulation of the first light output to create predetermined periods of light and dark for the second predetermined pigment of the plant to enhance growth of the plant.

3. The method of claim 1 wherein the light output is modulated by providing an AC input having a frequency of 60 Hz or less.

4. The method of claim 1 wherein the pigment is Chlorophyll A.

5. The method of claim 4 wherein the peak absorption of the predetermined pigment is 410 nm.

6. A lighting system for enhancing growth in plants comprising:

an input providing an input voltage to provide an applied electrical excitation;

a plurality of light emitting diodes (LEDs) arranged in a first network that receive a load current based on the applied electrical excitation;

said plurality of LEDs in the first network producing a first light output at a first wavelength that is within 20 nm of a peak absorption of a first predetermined pigment of a plant;

a plurality of light emitting diodes (LEDs) arranged in a second network that receives the load current based on the applied electrical excitation;

said plurality of LEDs in the second network producing a second light output at a second wavelength that is within 20 nm of a peak absorption of a second predetermined pigment of the plant; and

a control module electrically connected to the input to simultaneously modulate the first and second light outputs between light and dark for periods of less than 30 minutes.

7. The system of claim 6 wherein the control module determines the frequency of the AC input.

8. The system of claim 6 wherein the control module is a dimming device.

9. The system of claim 6 further comprising:

driving circuitry receiving the input voltage from the AC input and conditioning the load current to provide a first input current to the first network and a second input current to the second network;

wherein during operation the first input current provides current to the first network when the second input current provides no current to the second network.