Glossary A–ZLetter B
Backlight
The backlight is the light source behind the liquid crystal layer of an LCD that makes the picture visible in the first place.
Today it almost always consists of LEDs. A so-called LED television is therefore an LCD with LED backlighting and not an LED wall.
There are two basic designs: with edge lighting, the LEDs sit at the edge and the light is spread across a plate, which allows slim devices. With direct lighting, the LEDs are spread across the area behind the panel, giving more brightness and more even light. Some displays dim individual zones separately so that dark parts of the picture become darker.
Operators should know that the backlight uses most of an LCD’s electricity and loses brightness over time. Running it permanently at the highest level costs more electricity and shortens its life. Brightness control via an ambient light sensor or fixed levels by time of day helps. Uneven lighting shows up as bright corners or clouds on dark areas.