VIVID - LED Phosphor

Some rare-earth doped Sialons are photoluminescent and can serve as phosphors. Europium(II)-doped β-SiAlON absorbs in ultraviolet and visible light spectrum and emits intense broadband visible emission. Its luminance and color does not change significantly with temperature, due to the temperature-stable crystal structure. It has a great potential as a green down-conversion phosphor for white LEDs; a yellow variant also exists. For white LEDs, a blue LED is used with a yellow phosphor, or with a green and yellow SiAlON phosphor and a red CaAlSiN₃-based (CASN) phosphor.

White LEDs can also be made by coating near ultraviolet (NUV) emitting LEDs with a mixture of high efficiency europium based red and blue emitting phosphors plus green emitting copper and aluminium doped zinc sulfide (ZnS:Cu,Al). This is a method analogous to the way fluorescent lamps work.

Some newer white LEDs use a yellow and blue emitter in series, to approximate white; this technology is used in some Motorola phones such as the Blackberry as well as LED lighting and the original version stacked emitters by using GaN on SiC on InGaP but was later found to fracture at higher drive currents.

Many white LEDs used in general lighting systems can be used for data transfer, for example, in systems that modulate the LED to act as a beacon

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