How Are Neon Lights Made?

Chris Cheadle/All Canada Photos/Getty Images

Neon lights use glass tubes filled with a low-pressure gas that glows under high voltage. A sign maker shapes one or more of the tubes as desired, adds a fluorescent coating and then fills them with special gases. This assembly includes electrodes at each end of the tube connected to a transformer. When power is applied, the gas glows in the tubes, and the sign displays its message.

Neon lights glow because the high voltage ionizes the low-pressure gas, which in turn fluoresces with a color based on the gas used. Neon emits a signature red color, helium yellow, argon green and mercury vapor blue. Combining these and other gases creates a wide array of possible colors.

The sign maker shapes glass tubes forming letters or other forms, adds fluorescent coatings as desired and then connects electrodes to each. The assembly is then connected to a manifold, which has both a vacuum pump and the desired gas. The sign maker removes the air first and then introduces the desired gas at very low pressure. Finally, the sign maker seals the glass assembly then mounts it along with the transformer, connecting cables and switches.

Neon lights glow steadily using a constant voltage. Switching the voltage on and off creates the classic flashing seen on many signs. A combination of tubes, transformers and switches creates the animated effect seen on classic signs such as ?Vegas Vic? in Las Vegas, Nev.

Although neon lights are bright and seemingly modern, Arizona State University points out that the technology that makes these lights possible was actually developed in 1910.