luminescent lamp

Luminescent lamps are devices that emit light without significant heat, often referred to as "cold light". This phenomenon is distinct from incandescence, where light is produced by high temperatures.1

Luminescent lamps encompass various types, including electric discharge lamps, semiconductor lamps, and chemical lamps. A common example is the fluorescent lamp, which uses mercury vapor excited by an electric discharge. This discharge produces ultraviolet light that is then converted into visible light by a phosphor coating on the lamp's inner walls. Other electric discharge lamps include sodium vapor lamps, which emit a yellow-orange light, and mercury vapor lamps, producing a blue-green glow.23

Semiconductor lamps, such as light-emitting diodes (LEDs), also fall under this category. LEDs are crystalline semiconductor diodes that emit photons when current flows through them, with the color of light depending on the crystal material. Electroluminescent lamps, another type of semiconductor lamp, use a phosphor in a capacitor-like structure to produce light when an electric field is applied.2

The practical value of luminescent materials lies in their ability to transform invisible energy into visible light.1