Abstract: A first set of orange LEDs with a peak wavelength emission of about 612 nanometers, a second set of red light emitting LEDs with a peak wavelength of about 660 nanometers, and blue light LEDs. Two beam spreads, 15° and 30°, were provided for both the 660 nm LEDs and 612 nm LEDs. When directed perpendicularly upon tops of the plant leaves, 10% light transmission occurred through the leaves for the 30° LEDs, and 80% light transmission for the 15° LEDs. Thus, fully 50% of the orange/red spectrum primarily used for photosynthesis was transmitted through the upper leaf canopy, making it available to support photosynthesis in leaves below. LED lamps are positioned at varying distances from the growing plants for controlling plant growth rates that vary with these distances, thereby to control plant inventory, because growth of plants can be greatly slowed to preserve them during periods of slow sales.

Abstract: A first set of orange LEDs with a peak wavelength emission of about 612 nanometers, a second set of red light emitting LEDs with a peak wavelength of about 660 nanometers, and blue light LEDs. Two beam spreads, 15° and 30°, were provided for both the 660 nm LEDs and 612 nm LEDs. When directed perpendicularly upon tops of the plant leaves, 10% light transmission occurred through the leaves for the 30° LEDs, and 80% light transmission for the 15° LEDs. Thus, fully 50% of the orange/red spectrum primarily used for photosynthesis was transmitted through the upper leaf canopy, making it available to support photosynthesis in leaves below. LED lamps are positioned at varying distances from the growing plants for controlling plant growth rates that vary with these distances, thereby to control plant inventory, because growth of plants can be greatly slowed to preserve them during periods of slow sales.

Abstract: A power conditioning circuit is coupled between a conventional low-voltage 12 volt AC switching power supply used in track lighting arrangements and an LED array used for illumination of an area. A conventional voltage multiplier is provided having a low input impedance for producing a current inrush from the switching power supply, sufficient in magnitude and duration to excite the low-voltage switching supply in spite of the low LED load to be energized. The resulting voltage multiplied and rectified current is fed to a precise DC voltage regulator for very efficiently driving an array of series-parallel strings of light emitting diodes. The use of the voltage multiplication combined with precise DC voltage regulation feature enables driving LED arrays having the longest possible light emitting diode serial strings for the available voltage, increasing energy efficiency while keeping the circuit near ambient temperature.