We switch on the lights in the evening when it is getting dark.
We can be active during the night hours thanks to such fluorescent, incandescent and LED bulbs.
Incandescent bulbs are being replaced by LEDs, but vacuum is still utilized in mainstream fluorescent lighting.
This section provides a simple explanation of how vacuum is used in fluorescent lamps.
In the first place, why do fluorescent bulbs glow?
The inside of the glass tube of a fluorescent lamp is coated with a fluorescent substance.
Inside is a vacuum, containing a chemically stable gas such as argon, and a small amount of mercury gas.
Click here to find out more about argon.
It has positive and negative electrodes at both ends.
Electricity is then applied and the light is switched on when voltage is applied to the electrodes at both ends.
In this case, electrons are fly off from the – pole to the + pole.
This may be familiar to anyone who remembers learning about ‘vacuum discharge’ in secondary school science.
When these electrons collide with mercury electrons in the glass tube, ultraviolet rays are generated, and when the ultraviolet rays hit the fluorescent material coated inside the glass tube, it changes into light that we can see (visible light).
Click here to find out more about the different types of lights.
This mechanism allows us to live under bright light at night.
Vacuum in fluorescent lamps
When air is present, it is crawling with various air particles (molecules) such as nitrogen and oxygen, which makes it difficult for electricity to flow (electrons do not easily move to the – pole and + pole).
However, inside the glass tube of a fluorescent lamp is a vacuum, which means that there is almost no air particle.
This makes it easier for electricity to pass through.
Incandescent bulbs also use a vacuum
Even incandescent bulbs, which are now replaced by LEDs and are seen less frequently, use a vacuum.
Unlike fluorescent light bulbs, incandescent bulbs do not blow electrons from the – pole to the + pole, but they are vacuumed to reduce the burning of the filament inside.
By doing so, the filament was prevented from oxidation and it can extend life of the incandescent bulbs.
We have a variety of vacuum equipment, including sputtering equipment that utilizes vacuum and argon gas to deposit films.
For more information on our vacuum equipment, click here.
