LCD screens cannot illuminate themselves, so they require a backlight to provide the illumination, thus creating a viewable picture on the screen. Backlights can provide illumination from the back or the side of the screen, which are different from front lights that illuminate from the front.
There are five types of light sources used for backlights.
- Incandescent light bulbs.
- LEDs light-emitting diodes).
- ELPs (electroluminescent panels).
- CCFLs (cold cathode fluorescent lamps).
- HCFL (hot cathode fluorescent lamps).
Only the ELP provides uniform light over the entire surface. The other light sources employ a diffuser to provide uniform light.