White LED

A white LED produces white light by combining blue or ultraviolet emission with light converted by phosphors. Its color and efficiency depend on the emitter, phosphor, and optical design.

Phosphor-converted LED: An LED whose short-wavelength emission excites phosphors that emit longer-wavelength light. This is the dominant white-LED design: blue light excites phosphors that fill out the spectrum.
Light-emitting diode: A semiconductor device that emits light when electrical current drives electron-hole recombination. White LEDs build on the electroluminescence mechanism shared by all LEDs.
Solid-state lighting: Lighting produced by semiconductor devices such as LEDs and organic LEDs rather than heated filaments or gas discharges. White LEDs are a leading technology within this broader shift in lighting.
RGB LED: A light source that combines red, green, and blue LEDs to produce different perceived colors, including white. Unlike phosphor-converted white LEDs, it synthesizes white from separate colored emitters.
Blue LED: A semiconductor light-emitting diode that emits blue light, commonly using gallium nitride materials. Its blue output both contributes directly to white light and excites the phosphor layer.
Gallium nitride: A wide-bandgap semiconductor used in blue and ultraviolet LEDs and other electronic devices. Its bandgap enables the short-wavelength emission used to make white LED light.
LED lamp: A complete electric lamp that uses light-emitting diodes and supporting electronics to provide illumination. It packages white LEDs with drivers, optics, and thermal management for ordinary fixtures.
Tunable white: A lighting system that adjusts the correlated color temperature of its white output. It contrasts fixed-color white LEDs with systems designed to shift between warm and cool white.
Photoluminescence: Light emission from a material after it absorbs photons and undergoes electronic excitation. Phosphors create the longer-wavelength component of many white LEDs through this process.
Phosphor: A luminescent material that absorbs energy and re-emits part of it as light. The phosphor composition sets much of a white LED's spectrum and color rendering.

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