Light sources adapted to spectral sensitivity of plants

• US 10,028,448 B2
• Filed: 04/17/2015
• Issued: 07/24/2018
• 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
• Primary Examiner(s): Hayes, Kristen C
• Application Number:
  US14/689,117
• Publication Number:
  US 20150216130A1
• Time in Patent Office: 1,194 Days
• 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, with at least one lighting element, a light output at a wavelength that is within 20 nm of a peak absorption wavelength of a predetermined pigment of a plant;

positioning the lighting element adjacent to 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 plant;

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

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

producing, with a second lighting element, a second light output at a second wavelength that is within 20 nm of a second peak absorption wavelength of a second predetermined pigment of the plant; 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 2 wherein the second predetermined pigment is Chlorophyll B.

4. The method of claim 3 wherein the peak absorption wavelength of the second predetermined pigment is about 665 nm.

5. The method of claim 2 wherein the second predetermined pigment is Chlorophyll A;

and the peak absorption wavelength of the second predetermined pigment is 690 nm.

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

7. The method of claim 6 wherein the peak absorption wavelength of the predetermined pigment is 410 nm.

8. The method of claim 1 wherein the predetermined pigment is Chlorophyll B.

9. The method of claim 8 wherein the peak absorption wavelength of the predetermined pigment is 420 nm.

10. The method of claim 1 wherein the predetermined pigment is carotenoid.

11. The method of claim 10 wherein the peak absorption wavelength of the predetermined pigment is 415 nm.

12. The method of claim 1 wherein the predetermined periods of light and dark have a phase of up to thirty minutes.

13. The method of claim 1 wherein the predetermined periods of light and dark have a phase of 24 milliseconds (ms).

14. The method of claim 13 wherein a period of darkness in the predetermined periods of light and dark has a duration of 3.5 to 14.5 ms.