Pulsed-lighting LED luminaire for agriculture with a geometrical optical solution.

Light-emitting diodes (LEDs) are the 4th plant supplemental lighting source. Pulsed lighting is benefit to increase energy utilization efficiency in greenhouse production. A pulsed-lighting LED luminaire with geometrical optical solution is proposed to overcome the shortcoming with pulse width modulation (PWM) solution. In addition, this luminaire also achieves uniform lighting by designing optical surfaces. In the illumination area, the lighting frequency is 117.6 Hz and the illuminance uniformity is 0.789, which is better than 0.75 (+/- 12.5%). In an actual planting experiment of Brassica chinensis, the average fresh weight of the plants under the pulsed-lighting LED luminaire was 33.1% higher than that under the conventional LED luminaire. The results showed that the energy utilization efficiency of the pulsed-lighting LED luminaire is 22.9% higher than that of the conventional LED luminaire.