An unconscious discovery in 1675 led togas-discharge lamps: the French astronomer Jean Picard saw a weak light on top of a glass tube at the end of a mercury barometer. The static electricity was ionizing the mercury molecules present in the upper cavity, which was saturated with steam. When the basic principles of electricity were discovered, the phenomenon could finally be explained and defined as an ionized gas discharge from which an entire range of lamps that are still widely used in lighting would be born.
The French chemical engineer Georges Claude (1870-1960) was the first to apply an electric discharge in a sealed tube full of a recently discovered gas in 1902.In 1898, in London, William Ramsey and MW Travers discovered neon as a rare gaseous element in the atmosphere (1 part out of 65,000 of air). It is obtained by liquefying air and by separating the other gases by fractional distillation.
The term neon derives from the Greek word "Neos," which means "new gas." Georges Claude introduced the first neon lamp to the public on December 11, 1910, in Paris.
Within eight years, a very economic method to extract neon from the air was discovered and made it possible to market the lamps on a large scale. In 1912, Jacques Fonseque, Claude's partner, sold the first neon sign to a barber shop; in 1913, the "CINZANO" sign - whose letters were all one meter high - was exposed on the Champs-Elysées for everyone to see: the neon era had begun. World War I broke out, the cities were darkened: the right time for the diffusion of light sources had not come yet. The French Army was also interested in Claude, who interrupted his activity to work for the military. The war ended and things slowly returned to normal. In 1922, the Dutch company Haaxman Brothers had a neon sign installed, which became the first one in the Netherlands.
Then, in 1923, Georges Claude and his company "Claude Neon" landed on the US market with the first neon signs: the first customer was a car dealer, Packard, from Los Angeles. Anthony C. Earle bought two "Packard" neon signs for 24,000 dollars.
Visible also in the daylight, they represented a real attraction: people were enchanted and stopped to stare at them and the same were soon renamed "liquid fire". Since then, neon signs have been widely used in advertising.
What is Cold Cathode?
The cold cathode lamp, also generally known as “neon” is a system which includes different components:
- glass tube which can be trasparent or coloured, the latter it is produced in Murano-Venezia
- pure or mixed noble gases
- fluorescent powders which transform UV light (not visible) into a visible light
- electrodes at the end of each tube
- transformer for converting the voltage of “common socket” to a suitable voltage for functioning of the lamp
Cold Cathode VS Hot Cathode
Cold cathode is a handmade lamp, so called because during the functioning it never exceeds 40°C but only within electrodes the metallic cylinder can reach 200°.
Therefore, the lamp can be hold in hands without searing.
The life of the lamp has 50’000 hour average life, but a right execution and a suitable equipment can be clearly superior.
The hot cathode is instead typical of most common fluorescent lamps as industrial production. It has electrodes which can endure a heat up to 900° in correspondence with the tungsten filament and with a really high outdoor temperature.
Generally, it does not exceed 15’000 hour life.
[Credit image: Luxemozione]
