LIGHTING SYSTEM

• US 20130258684A1
• Filed: 03/14/2013
• Published: 10/03/2013
• Est. Priority Date: 03/30/2012
• Status: Active Grant

• Current Assignee: Corteva Agriscience LLC (Corteva, Inc.)
• Original Assignee: Dow Agrosciences LLC (Corteva, Inc.)
• Inventors: Yang, Yang, Burroughs, Frank, Curlee, Kristen
• Granted Patent: US 10,767,839 B2
• Time in Patent Office: Days
• US Class Current: 362/386
• 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: F21V 14/02 by movement of light sources in vehicle head lamps F21S41/657
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/115 by determining the presence or movement of objects or living beings
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection
• CPC Class Codes: Y02P 60/14 Measures for saving energy, e.g. in green houses

Abstract

An apparatus and a method of using at least one of a distance sensor and a light intensity sensor to adjust the distance between an artificial light source and plant canopy to control light intensity at the plant canopy is disclosed.

Claims

1. An apparatus for controlling the light intensity received at a plant canopy comprising:

an artificial light source positioned generally above a plant canopy;

a light intensity sensor positioned to measure a light intensity, the light intensity corresponding to one of the plant canopy and a distance above the plant canopy;

a first height adjustment unit configured to adjust the distance between the artificial light source and plant canopy;

wherein the first height adjustment unit adjusts the distance between the artificial light source and plant canopy in response to the light intensity measured by the light intensity sensor.

2. The apparatus of claim 1, further comprising a distance sensor coupled to the artificial light source, the distance sensor measures a distance between the distance sensor and the plant canopy.

3. The apparatus of claim 2, further comprising a second height adjustment unit configured to adjust the relative position of the light intensity sensor to the artificial light source, wherein the second height adjustment unit adjusts the relative distance between the artificial light source and light intensity sensor to maintain the light intensity sensor at a predetermined distance above the plant canopy.

4. The apparatus of claim 3, wherein the artificial light source, distance sensor, and second height adjustment unit are supported by a light frame.

5. The apparatus of claim 2 wherein the apparatus is located in a greenhouse having an internal frame, the artificial light source and distance sensor are supported by a light frame, and the first height adjustment unit is attached to the internal frame.

6. The apparatus of claim 2 wherein the first height adjustment unit comprises a rotatable member, a drive for rotating the rotatable member, and a plurality of cables having a first end wrapped around the rotatable member and a second end attached to a light frame rigidly attached to the artificial light source, the plurality of cables raising the light frame when the drive rotates the rotatable member in a first direction and lowering the light frame when the drive rotates the rotatable member in a second direction.

7. The apparatus of claim 2 wherein the distance sensor is an ultrasound sensor.

8. An apparatus for providing artificial light to a plant canopy comprising:

an artificial light source positioned generally above a plant canopy;

a position sensor coupled to the artificial light source and measuring a distance between the distance sensor and the plant canopy; and

a first height adjustment unit configured to automatically adjust the position of the artificial light source in response to the distance measured by the position sensor.

9. The apparatus of claim 8, wherein the height adjustment unit adjusts the position of the artificial light source to maintain a predetermined distance between the artificial light source and the plant canopy.

10. The apparatus of claim 9, further comprising:

a light intensity sensor positioned to measure a light intensity, the light intensity corresponding to one of the plant canopy and a distance above the plant canopy; and

a second height adjustment unit configured to adjust the relative position of the light intensity sensor to the artificial light source;

wherein the second height adjustment unit adjusts the relative position of the light intensity sensor to the artificial light source to maintain the light intensity sensor at a predetermined distance above the plant canopy.

11. A method of controlling the light intensity received at a plant canopy comprising the steps of:

providing a plurality of plants defining a plant canopy;

providing artificial light from an artificial light source positioned above the plant canopy;

measuring a light intensity with a light intensity sensor at one of the plant canopy and a predetermined distance above the plant canopy; and

adjusting the distance between the plant canopy and artificial light source in response to the measured light intensity.

12. The method of claim 11 further comprising the steps of:

determining the distance between the light intensity sensor and the plant canopy; and

adjusting the position of the light intensity sensor relative to the artificial light source to position the light intensity sensor at the predetermined distance above the plant canopy.

13. The method of claim 11 further comprising dimming the artificial light source in response to the measured light intensity.

14. The method of claim 11 further said adjusting step further comprises the steps of:

(a) providing a target light intensity;

(b) comparing the measured light intensity with the target light intensity;

(c) increasing the distance between the plant canopy and artificial light source when the measured light intensity is greater than the target light intensity; and

(d) decreasing the distance between the plant canopy and artificial light source when the measured light intensity is less than the target light intensity.

15. The method of claim 14, wherein steps (a)-(d) are repeated at predetermined intervals.

16. The method of claim 15, wherein the target light intensity at each predetermined interval is the same.

17. The method of claim 15, wherein the target light intensity at each predetermined interval is cumulative of the target light intensity of previous periods and the measured light intensity at each predetermined interval is cumulative of the target light intensity of previous periods.

18. A method of controlling the light intensity received at a plant canopy comprising the steps of:

providing a plurality of plants defining a plant canopy;

providing artificial light from an artificial light source positioned above the plant canopy; and

automatically adjusting a distance between the plant canopy and the artificial light source to maintain a threshold separation distance between the plant canopy and the artificial light source.

19. The method of claim 18, further comprising the step of measuring a separation distance between the plant canopy and the artificial light source and when the separation distance is less than the threshold separation distance raising the artificial light source relative to the plant canopy.

20. The method of claim 19, further comprising the steps of

supporting the artificial light source with a light frame;

and

supporting a distance sensor used to measure the separation distance with the light frame.