The following video about the fluorescent tube production system is the one that I have liked the most so far of all those seen in How is it done?.
A true work of art of the production lines.
The operation of the tube is explained in the video, the inner part is covered with phosphor which is the one that illuminates when the mercury drop that is introduced is ionized. But let's go in more detail
In 1909, the Frenchman George Claude, considered the French Thomas Edison, invented the neon lamp with electric discharges on inert gases.
- The tubes are cleaned with hot water to remove impurities,
- The tube is then heated to the desired shape by bending the glass.
- A thin layer of phosphor is applied to the inside of the tubes. The phosphor is the one that emits light, transforming the ultraviolet that has been produced from the ionization of mercury.
- The excess phosphorus is eliminated, it is sealed and the electronics are applied,
- with a liquid on the filament in the cathode that when heated emits electrons.
- finally the air is extracted and a drop of mercury is introduced that is necessary for everything to work
In the end, it is a complicated process despite having occurred at the beginning of the 20th century and remains practically the same to this day. Interesting details about the manufacturing process are the threader, the wheel where all the tubes are tested and their sealing.
All this and details that we have not put you can see them carefully in the video.
It is not the most ecological item there is and little by little I suppose they will be retired, but the video is worth watching.
If you are more interested in knowing why they work, I leave you two links