Backlight type：

LED backlight：LED backlight is very common in the middle small size LCD displays. Its advantage is low cost, long life, no electromagnetic, low operation voltage, and easy to control the brightness. LED backlight is divided into two type, bottom backlight and side backlight. The button backlight is more thickness, power dissipation is increase by the area, uniformity, good brightness, in order to eliminate the shadow, the thinner the thickness, the more led it needs. The side backlight is thin, from 0.7-4.0mm, common is 2.5mm, low consumption and brightness, it required a certain width to make the display area equality.

EL backlight：EL is high luminous efficiency, low consumption, light weight, thin, shock proof, no necessary to protect, and it belong to cold light source, color displays uniformity. Compared with common LED backlight’s inhomogeneity, EL light’s most obvious advantages are：its backlight can light more uniform on the screen. Besides, it can save power. EL’s disadvantages are：low light, short life（common is 3000-5000h）, light the EL led, it will vibrate easily. It needs alternating current（80-110V）to drive, and can make the IC become 5V, 12V or 24V by the specified inverter.

CCFL backlight：CCFL is a new type light source, its theory is that when high pressure work on the light both ends, a few primary electrons will have high speed impact and produce second electron emission and begin to discharge, it is famous for its low temperature. It BL can provide low consumption and very brightness white light, and have very long life. So it required a inverter in the work time, to provide CCFL’s light 270-300 VAC high pressure. The biggest weakness is, it has great influence by temperature.

LED、EL and CCFL comperation: