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 printer LED printer An LED printer is a type of computer printer similar to a laser printer. LED technology uses a light-emitting diode array as a light source in the printhead instead of the laser used in laser printers and, more generally, in the xerography process. The LED bar pulse-flashes across the entire page width and creates the image on the print drum or belt as it moves past. LEDs are more efficient and reliable than conventional laser printers, since they have fewer moving parts, allowing for less mechanical wear. Depending on design, LED printers can have faster rates of print