Inventive Genius: Colourful World of Neon

GEORGES Claude (1870-1960), a French engineer, invented neon signage.

That lit up the world of street advertising.

His moment of ingenuity came from his work on the industrial liquefaction of air.

Known as the “Edison of France”, in 1896, Claude learned of the explosion risk for bottled acetylene, which was used at the time for lighting. Acetylene is explosive when stored under pressure. Claude showed that acetylene dissolved well in acetone, equivalent to storing it under 25 atmospheres of pressure, reduced the risk in handling the gas.

In 1902 Claude devised what is now known as the Claude system for liquefying air. The system enabled the production of industrial quantities of liquid nitrogen, oxygen, and argon; Claude’s approach competed successfully with the earlier system of Carl von Linde.

Inspired by Geissler tubes and by Daniel McFarlan Moore’s invention of a nitrogen-based light (the “Moore tube”), Claude developed neon tube lighting to exploit the neon that was produced as a by-product of his air liquefaction business.

These were all “glow discharge” tubes that generate light when an electric current is passed through the rarefied gas within the tube. Claude’s first public demonstration of a large neon light was at the Paris Motor Show in 1910.

Claude’s first patent filing for his technologies in France was in March 1910. Claude himself wrote in 1913 that, in addition to a source of neon gas, there were two principal inventions that made neon lighting practicable. First were his methods for purifying the neon (or other inert gases such as argon).

Claude developed techniques for purifying the inert gases within a completely sealed glass tube, which distinguished neon tube lighting from the Moore tubes; the latter had a device for replenishing the nitrogen or carbon dioxide gases within the tube. The second invention was ultimately crucial for the development of the Claude lighting business; it was a design for minimising the degradation (by “sputtering”) of the electrodes that transfer electric current from the external power supply to the glowing gases within the sign.

The terms “neon light” and “neon sign” are now often applied to electrical lighting incorporating sealed glass tubes filled with argon, mercury vapour, or other gases instead of neon. In 1915 a US patent was issued to Claude covering the design of the electrodes for neon lights; this patent became the strongest basis for the monopoly held in the US by his company, Claude Neon Lights, through the early 1930s.

In 1923, Georges Claude and his French company Claude Neon, introduced neon gas signs to the United States, by selling two to a Packard car dealership in Los Angeles.

Earle C. Anthony purchased the two signs reading “Packard” for $1,250 apiece. Neon lighting quickly became a popular fixture in outdoor advertising. Visible even in daylight, people would stop and stare at the first neon signs for hours, dubbed “liquid fire.”