Gas & glass:
how do neon lights work?
What are neon signs?
From today's point of view, their production and use seem relatively complex and even somewhat complicated, but nevertheless neon signs are one of the oldest advertising techniques still in use in the world with a long tradition – there’s a reason that neon tubes are often qualified with the addition "classic".
How neon lights work has not lost its fascination even after more than 100 years of commercial use. That is exactly why we want to give an insight into the world of the shaped glass tubes!
When were neon lights invented and by whom?
The history of neon
Neon is a noble gas and thus in the eighth main group of the periodic table (group 18 according to the newer classification). Like its "siblings" helium, argon, krypton, xenon and radon, it was discovered in the 19th century. The inventor of the neon tube as we still know it today is considered to be the Frenchman Georges Claude, who developed the technology as the first practical application of the gas around 1910 and patented it in 1915.
Neon tubes in the form of illuminated advertising therefore first became extremely popular in Paris, at that time one of the cultural centres of the Western world. Nowadays, neon signs are probably more commonly associated with Asian metropoles such as Tokyo and Hong Kong, or major US cities such as New York and Las Vegas.
What is neon light made of?
Classic Red & Classic Blue
The technical generic term for neon tubes is gas discharge tubes, or more precisely: cold cathode fluorescent lamps (short: CCFL). No wonder, then, that the colloquial name "neon" became established after the inert gas originally used in them. Incidentally, the name comes from the Greek word for new: νέος (néos). In fact, most modern luminous signs no longer contain (only) neon, but its neighbouring gas argon (or a mixture of both). The reason for this is that argon is more reactive than neon, and thus less energy is necessary to make it glow.
Theoretically, all naturally occurring noble gases react to electricity with colored discharge: helium glows orange-yellow, krypton white or blue, xenon blue, and the radioactive radon red. The natural colour of neon is a bright red and that of argon is a pale purple/pink or light blue – hence our neon colours Classic Red and Classic Blue. Nowadays, only the latter two gases are primarily relevant for the production of neon signs.
Incidentally, neon gas is also used in neon glow lamps (sometimes just known as “neon lamps”), which are another type of gas discharge tube.
How do neon lights work?
To understand this, you have to go to the molecular level. Don't worry, this is not going to be a physics treatise!
Firstly, the construction: A "classic" (there is the word again) neon sign consists of individual glass tubes with electrodes at both ends, one negative and one positive. The glass tubes are filled with a small amount of gas or gas mix, and the electrodes are typically painted with a covering colour.
Alternating current is supplied from both sides of the glass tube, which is why a high-voltage cable leads from each of the two electrodes to the converter. The choice of the right transformer model with the individually required voltage influences the function as well as, among other things, the lifespan of the neon sign and is therefore a bit of a science in itself!
What happens inside the neon tube
- The supply of the high-voltage current in the range of 2-12kV (kilovolts) creates an electric field in the tube, which sets the gas atoms in motion.
- The atoms ionise, i.e., they repel individual electrons, thereby acquiring a positive voltage. The positive ions are attracted to the negatively charged electrode and move toward it, while the electrons fly toward the positive pole.
- The opposing motion currents cause a chain reaction in which the released electrons collide with the ions, thus "knocking" more electrons out of the atomic shell. This process (explained here in a very simplified way) is called impact ionisation.
Another side effect of the accelerated particle movement is the emission of heat. However, this is significantly lower with neon than, for example, with lamps using conventional light bulbs.
When a gas ion "recaptures" an electron on impact (recombination), energy is released in the form of a photon (light particle). This leads to the typically colored gas discharge. The individual colour, in turn, results from the characteristic wavelength of the photons of the respective noble gas.
Since neon tubes primarily use neon and argon, as explained above, the gas discharge is either red or blue. The wide colour spectrum of our glass neon products is achieved by treating the glass: by coating the tube with fluorescent powder or colouring it, the light appears white, pink, green or yellow.
Dimmable neon lights
Dimming can generally slow down or reduce the molecular processes described. Traditionally, dimmable transformers are used for glass neon, where the current supply and voltage are lowered manually. As a result, fewer ionisation and recombination processes take place, resulting in reduced light output.
Dimmable transformer models can be selected in our Neon Configurator or ordered individually online in our Accessories shop.
Want to know more?
You can find out more about neon on our Neon product page or in our technical catalogue.
For more information about the production of neon signs, please read our article Neon tube lights – a true allrounder.