What are the different types of backlights?

EL (Electroluminescent Lamp)

An EL backlight is a solid-state component, which uses colored phosphors to generate light.
These EL backlights are thin, lightweight, and provide very uniform lighting. EL panels are
available in a wide variety of colors. While their power consumption is moderately low, they
require voltages of 100 VAC @ 400 Hz supplied by an inverter that converts a 5, 12, or 24 VDC
input to the AC output. EL backlights also have a limited half-life of 3,000 to 5,000 hours. The

biggest drawbacks to an EL panel are the added cost for the inverter and the limited lifespan. EL
panels are rarely used in new designs today because of these factors

Edge-Lit LED Backlight

Edge-lit LED backlights consist of LEDs placed along the side or sides of a thin plastic light
guide, which then transmit the light evenly through the LCD panel. This is the most common
type of backlighting used today.

Lifetime: 50,000-100,000 hours
Power: 5V DC typical

LED Array

LED array backlights are composed of surface-mount LEDs, which are configured in a matrix
along the bottom of a shallow plastic tray and encapsulated with a clear epoxy. These LEDs form
a grid across the entire viewing area of the LCD display and emit directly up through a diffuser
film and into the LCD display, rather than from the side like the edge-lit type.

CCFL (Cold Cathode Fluorescent Lamp)

Made of lead glass with mercury, Cold Cathode Fluorescent Lamps are small high-voltage field
emission lamps that provide a fluorescent light source. The CCFLs are used in conjunction with
the plastic light guide to evenly disperse light through the front surface of the LCD panel. Given
the power consumption, the cost, and the hazardous materials, CCFLs are rarely used in today’s
designs.

Lifetime: 15,000-30,000 hours
Power: 300V AC typical