LED (Light-Emitting Diode)
LED backlights consist of surface mount LED’s, which are positioned in a matrix along the bottom of a shallow plastic tray and encapsulated with a clear epoxy (LED array type). For an edge lit display, LED’s are placed along the side or sides of a thin plastic light guide which then transmits the light evenly through the LCD panel.
Power 5V DC typical
EL (Electro Luminescent)
EL panels are a thin membrane device consisting of two coated electrode plates sandwiching a thin film of phosphorescent substance between two plates. When AC voltage is applied to the electrode plates, the electrons collide with the light emission core. The energy given off is light. EL panels come in a variety of color and require an inverter to create the AC voltage.
Power 70V – 150V AC typical
CCFL (Cold Cathode Florescent Lamp)
CCFL lamps are small high voltage field emission lamps made of lead–glass with mercury providing a fluorescent light source. The CCFL lamps are used in conjunction with the plastic light guide to evenly disperse light evenly through the front surface of the LCD panel.
Power 300V AC typical