Difference Between Fluorescent Light and Neon Light

Neon lights are a type of light commonly used in advertising signs. These signs are made of long, narrow glass tubes that are often bent into various shapes. For example, neon tubes can spell out words. These tubes can also glow in different colors.

On the other hand, a fluorescent lamp is usually a long, straight tube that emits white light. You can find fluorescent lamps in offices, stores, and homes.

The concept of a neon sign is simple - a low-pressure inert gas such as neon, argon or krypton is placed inside a glass tube, with metal electrodes at either end. When high voltage is applied to the electrodes, the neon gas ionizes, and electrons flow through the gas. These electrons excite the neon atoms, causing them to emit light that we can see. When excited in this way, neon glows red, while other gases glow in other colors.

Fluorescent lamps work in a similar way, but with one extra step. Inside a fluorescent lamp, there is mercury vapor at low pressure. When ionized, the mercury vapor emits ultraviolet light. The human eye is not sensitive to ultraviolet light (although human skin is - see How Sunburn and Tanning Occur), so the inside of fluorescent lamps is coated with a phosphor. A phosphor is a substance that can accept energy in one form (for example, from high-speed electrons in a picture tube - see How Television Works) and emit it as visible light. In a fluorescent lamp, the phosphor accepts energy from ultraviolet photons and emits visible photons.

Therefore, the light we see from a fluorescent tube is the light emitted by the fluorescent substance coated on the inner surface of the tube (the fluorescent substance fluoresces when excited, hence the name). The light of a neon tube is the colored light emitted directly by neon gas.