Light sources adapted to spectral sensitivity of plant

• US 10,212,892 B2
• Filed: 07/09/2013
• Issued: 02/26/2019
• 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
• Primary Examiner(s): Hayes, Kristen C
• Application Number:
  US14/413,451
• Publication Number:
  US 20150150195A1
• Time in Patent Office: 2,058 Days
• CPC Class Codes: A01G 7/045 with electric lighting
• CPC Class Codes: H05B 45/10 Controlling the intensity 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 stimulating plant growth in a controlled environment steps comprising:

providing a pair of input terminals that are adapted to receive a periodic excitation voltage such that the terminals receive a current of equal magnitude and opposite polarity, said current flowing in response to the excitation voltage to provide an AC input;

providing a lighting assembly that has driving circuitry that receives the AC input and conditions the current;

providing a network of lighting elements that produce light at a predetermined wavelength n response to the conditioned current;

positioning the lighting assembly adjacent a plant such that the light produced is received by the plant; and

modulating the conditioned current of the lighting elements with a control assembly to controllably provide predetermined periods of light and dark to stimulate continuous growth of the plant;

wherein the predetermined periods of light are in a range between 3.5 ms and 24 ms and the predetermined periods of dark are in a range between 3.5 ins and 24 ms.

2. The method of claim 1 wherein the network of lighting elements are light emitting diodes (LEDs).

3. The method of claim 2 wherein the predetermined wavelength of the network is in a range including and between 350 nm to 500 nm.

4. The method of claim 3 wherein the lighting assembly has a second network of lighting elements that produce light at a predetermined wavelength that are LEDs in series with the network of lighting elements.

5. The method of claim 4 wherein the predetermined wavelength of the second network of lighting elements is in a range between 600-750 nm.

6. The method of claim 2 wherein the predetermined wavelength of the network is in a range including and between 600 nm and 750 nm.

7. The method of claim 1 wherein the control assembly comprises a dimming device electrically connected to driving circuitry that conditions current from an AC input.

8. The method of claim 7 wherein the driving circuitry includes at least one silicon controlled rectifier (SCR).

9. The method of claim 8 further comprising the step of phase cutting current flowing to the LEDs with the at least one SCR to controllably determine the duration of the predetermined periods of light and dark.

10. The method of claim 9 wherein the dimming device has a triac therein.

11. The method of claim 9 wherein the dimming device has a IGBT therein.

12. The method of claim 1 wherein the predetermined periods of light are in a range between 3.5 ms and 14.5 ms and the predetermined periods of dark are in a range between 3.5 ms and 14.5 ms.