LIGHTING:NEON LIGHTS

NEON LIGHTS

The technology behind how a neon light works is very different from that of normal incandescent lights. Electroluminescence, or the conversion of electricity directly into light, is the operating principle of neon lights. Neon lights are used in advertising signs and are made of long narrow glass tubes that are often bent in different shapes. These tubes can emit light in a variety of colors. The construction of a neon light is much like that of a fluorescent light tube. The glass tube is filled with a gas such as neon, argon, or krypton at low pressure. At both ends of the tube are metal electrodes. When a high voltage is applied to the electrodes, the gas ionizes, causing electrons to flow through the gas. These electrons excite the gas atoms and cause them to emit photons that we can see in the form of visible light. Neon gives off a characteristic red light, and other gases emit other colors of light. The main difference between a neon light and a fluorescent light is the lack of a phosphor coating. In a neon light, the visible light is produced directly from the excited gas and is visible to the human eye. Another example of electroluminescence is seen in Indiglo watches and alarm clocks. These oper- ate in a very similar manner to neon lights. A high voltage is applied to a thin panel that is coated with a layer of a conductor and a layer of phos- phor. When the voltage is applied, the phosphor emits visible light with- out emitting heat.