Light-emitting diode ways of producing white light-emitting diodes (WLEDs), LEDs that generate high-intensity white light. One is to use individual LEDs that emit three primary colors—red, green, and blue—and then mix all the colors to form white light. The other is to use a phosphor material to convert monochromatic light from a blue or UV LED to broad-spectrum white light, much in the same way a fluorescent light bulb works. The 'whiteness' of the light produced is essentially engineered to suit the human eye. The yellow phosphor in LEDs is cerium-doped YAG crystal, in powder form and may be suspended in plastic,
LED tattoo irritation because they are nanometers thick. LED tattoos would not interfere with normal physiological processes. The U.S. Food and Drug Administration (FDA) have approved LED technology but LED tattoos are undergoing continual development. One such medical application would be silk-silicon LEDs to create photonic tattoos which would assist in blood-sugar readings. Perfected for clinical use and mass production, these devices could see patients sent home from the GP or from surgery with a monitoring system that does the job of several heavy-duty machines—like electromyographs, an EEG or electrocardiogram—normally confined to hospitals. LED tattoo A light-emitting diode tattoo is a type