Light-emitting diode practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared light. Infrared LEDs are still frequently used as transmitting elements in remote-control circuits, such as those in remote controls for a wide variety of consumer electronics. The first visible-light LEDs were of low intensity and limited to red. Modern LEDs are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness. Early LEDs were often used as indicator lamps for electronic devices, replacing small incandescent bulbs. They were soon packaged into numeric readouts in the form of seven-segment displays and were commonly seen in digital clocks. Recent
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