Neon signs are built by long tubes that are in fact, luminous gas discharge tubes containing neon gases. Neon signs are electric signs. The first use of this was done by Georges Claude in 1910 at Paris Motor Show. It cannot be said exactly, but Neon signs gained their popularity in the U.S.A. between the year 1920 and 1960. Neon signs have other applications too, rather than just in the signage industry. Neon signs are used by artists and architects for enhancing their art and design of models. Neon signs with a modification can be used in plasma televisions and display monitors. The signage industry has been losing its stature in the past few decades; citizens are now coming forward for preserving and restoring their ancient Neon signs.
The reasons which made Neon signs invincible at their time and nowadays too are:
The main selling point of Neon signs is their extended work life. The wide range of colors used alongside with its long lifetime makes Neon signs artistic. These tubes require a lot of manual labor and time to be created. That is why to make the Neon signs viable for use it is necessary to make these signs last longer. The neon light’s brightness increases inversely with the diameter of the tubes used for containing the neon gas. But at the same time, the resistance of the tube also increases along with decreasing diameter of the tube. Due to this reason and the fact that the ionization of the neon molecule is greater at the centre of the tube, ions get transferred towards the tube walls. This creates a high voltage difference that reduces the gas and by doing so, the resistance within the tube increases to such a level that the tube is unable to illuminate anymore and hence, the tube dies out. But in case of the Neon signs, this process takes up to 50 years of the time when produced properly. This amount of life is more than enough for attracting the buyers to buy Neon signs.
- Bending of the tube:
Neon signs are not only used for illumination purposes but they can also be used in various shapes. The tube that contains the gas is made from glass. And like every other glass product, these tubes when heated become malleable. Thus, they are heated and then aligned with the desired shape of paper sign pattern, holding the graphics or the letters to which the tubes are supposed to look like. For keeping the diameter of the tube constant while shaping, the bender corks off the tube before starting to heat it. Then he or she is supposed to hold a blow hose made of latex rubber on the other end of the tube. This blow hose is used for blowing a minimal volume of air through the tube gently for keeping the diameter same. If there are more than a single curve in the design then each of the bendings is done one by one i.e., the second bending is done only after the first bending becomes complete. Each bending is meant to be done in a single heating, as once the glass gets cooled, heating it again increases the chance of cracking. If the tubes are not of the required length then extra tubes are added to the previous one by welding. The finished items should be airtight and its inside should be properly cleaned for avoiding disruption in function.
After the tubes and their bending is completed, the cold cathode electrode is inserted into the ends of the tubes. These electrodes are usually made of lead glass, which contains a metal shell through which two wires are protruded. These wires are then attached to the sign wiring. These processes are being done in a high vacuum and the seals are meant to be leak- proof. To make the tube free of air i.e., vacuum, a high-end vacuum pump is fitted with the tube with the help of a manifold. The evacuation process is done until the air pressure within the tube reaches the practical vacuum level of little torr. After reaching that certain amount of torr, the evacuation process is put on hold and a high amount of current is blasted through the low-pressure tube. This process is known as bombardment. The amount of current and voltage used in this process is much higher than the operating current and voltage of the Neon signs. The reason for doing so is to testify how much voltage and current the electrodes and the other equipment can handle without melting. For creating high voltage a transformer is used.
These three manufacturing processes, build the foundation of the popularity of Neon signs. First of all, their long lifetime gives them the edge over other lights. They can be bent to any shape so it is good for marketing ideas and the last process ensures the safety of the equipment in case of high voltage or current supply.