【R&D Department of Dong Xian Display】
An overview of LCD backlight types available.
LED (Light-Emitting Diode) - Consists of surface mount LED′s, which are situated in series along the bottom of a shallow plastic tray (array lit) or the edges of display (edge lit).
Features:
Available Colors: Yellow-Green (standard), Red, Amber, Green, Blue, White
Life time: long, typically 50,000 hours
Operating temperature range: -30 to +70 degrees C
Requires low voltage DC. No DC/AC inverter required
Simple connection +5 VDC (Anode) and ground (Cathode)
Two methods: matrix (array)or edge lighting
The typical voltage for all standard LED versions of LCE modules is 4.2 VD
EL ( Electro Luminescent) - A thin membrane consisting of two coated electrode plates with an aluminum reflector. When AC voltage is applied to the electrodes, the electrons collide with the light emission core. The energy given off is light. Inverter (DC to AC) is used to power electro luminescent lamps.
Features:
Available Colors: White (standard), Blue, Yellow-Green
Service Life: 4000 hours (driven with inverter, 20 C temp, and 70% humidity) and 1500 hours (driven with a fixed power supply and frequency generator, 20 C temp, and 70% humidity)
Operating temperature range: -20 to +50 degrees C
CCFL (Cold Cathode Fluorescent Lamp) - A miniature high voltage cold cathode (field emission) lamp made of lead-glass with mercury inside that provides fluorescent back lighting or edge lighting . Uses a diffusing light guide. High brightness, high efficiency and vibration-proof.
Features:
Available Colors: White (standard)
Life time: 15,000; 20,000 hours
Operating temperature range: -20 to +50 degrees C
Low power consumption and excellent lighting characteristics
Easy intensity control
Low heat generation and thin diameter lamp
FIBER OPTIC - Fiber optics are flattened and then sandwiched between two pieces of pliable plastic. The top piece is used as the diffuser. The opposite ends are tied into a coupler, which is connected to an LED or Halogen light source.
Features:
Available Colors: White, Green, Blue, Amber and Red
Life time: long, remote light source offers 10,000 to 100,000 hours life and easy replacement.
Operating temperature range (optical fibers): -40 to +85 degrees C
Low power consumption. Sources require less power than EL, CCFL, or LED Array and no inverter. As low as 10-20mA at 2vdc
Compact, panels are thin and sources are smaller than EL or CCFL inverters
Heat free, adds no heat or EMI to interfere with switch operation
Very durable. Optical Fibers are not affected by extremes in humidity (0% to 100%) and temperature
