LEDbacklit

LED backlighting refers to the use of light-emitting diodes (LEDs) as the illumination source for the back of a liquid-crystal display (LCD). In an LCD, the crystals modulate transmitted light rather than emitting it, so a backlight provides the visible brightness. LED backlighting replaced older CCFL (cold cathode fluorescent lamp) backlights in many displays, enabling thinner panels, lower power consumption, longer lifespan, and improved color control. White LEDs are typically used, produced by blue LEDs with a phosphor coating, though some high-end displays use RGB LED arrays for broader color gamuts.

Backlight configurations vary. Edge-lit LED designs place LEDs along the panel edges and diffuse light with a guide plate, enabling very thin screens. Direct-lit or full-array backlighting positions LEDs behind the active area; full-array systems can incorporate local dimming, where multiple LED zones adjust brightness independently to improve contrast. Local dimming is especially common in high dynamic range (HDR) displays, where it helps produce deeper blacks and brighter highlights.

Advantages of LED backlighting include increased energy efficiency, compact form factors, faster response times, and more stable color over time compared with CCFLs. RGB or tunable white LEDs can enhance color accuracy and gamut in some professional or high-end consumer displays. Limitations can include cost for advanced full-array with local dimming and potential brightness uniformity issues in edge-lit designs.

LED backlighting is now widespread in televisions, computer monitors, laptops, and mobile devices, constituting the dominant backlighting technology in modern LCDs.