Light-emitting diode emitted, so the attainment of high efficiency in blue LEDs was quickly followed by the development of the first white LED. In this device a :Ce (known as "YAG") cerium doped phosphor coating on the emitter absorbs some of the blue emission and produces yellow light through fluorescence. The combination of that yellow with remaining blue light appears white to the eye. However, using different phosphors (fluorescent materials) it also became possible to instead produce green and red light through fluorescence. The resulting mixture of red, green and blue is not only perceived by humans as white light but is
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