An infrared light-emitting diode (IR LED) is a solid-state light-emitting (SSL) device that produces light in the infrared band or range of the electromagnetic radiation spectrum. ... They are even in use in cameras; these infrared cameras use IR LEDs like a spotlight while remaining invisible to the naked eye. UV Light Emitting Diodes (LEDs) are a solid-state device that produces light when an electrical current is allowed to flow from the positive (p-type or anode) side of the circuit to the negative (n-type or cathode) side. ... Each LED is made to produce a specific narrow range of UV wavelength.