A backlight is a form of illumination used in liquid crystal displays (LCDs). ... The backlight is usually the first layer from the back. Light valves then vary the amount of light reaching the eye, by blocking its passage in some way. Most use a fixed polarizing filter and a switching one, to block the undesired light.

How does LED backlighting work?

An LED (Light-Emitting Diode) screen is an LCD screen, but instead of having a normal CCFL backlight, it uses LEDs as the source of light behind the screen. Companies label their TVs as LED, even though they're technically LCD; it can be confusing at times, but if you see an LED TV, you know it has an LCD panel.

What is the purpose of backlighting?

Backlight photography emphasizes the depth behind the subject and gives images a greater sense of place. Dramatic effect. Backlighting can produce a dramatic contrast between the subject and the background. This can be an especially effective technique when shooting outdoor portraits.