Argon is often used when an inert atmosphere is needed. It is used in this way for the production of titanium and other reactive elements. It is also used by welders to protect the weld area (Argon-Gas-Blanketed Alternating Electric Current Arc Welding Aluminum And The Alloysthereof With A Tungsten Electrode And Superimposed High-Frequency High-Voltage Electric Current (1949)) and in incandescent light bulbs to stop oxygen from corroding the filament (Electric Incandescent Lamps Filled with Argon (1917)).
Argon is used in fluorescent tubes and low-energy light bulbs. A low-energy light bulb often contains argon gas and mercury. When it is switched on an electric discharge passes through the gas, generating UV light. The coating on the inside surface of the bulb is activated by the UV light and it glows brightly (Environment-friendly neon, argon, and fluorescent glow lamp (2007)).
Double-glazed windows use argon to fill the space between the panes: Argon Filled Double Glazing Unit With Low Emissivity Coatings (1995)).
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All patent information has been obtained from Espacenet (European Patent Office).