Neon is mostly used in the “neon” advertising signs found everywhere: ‘Improvements in neon and like lamp lighting systems and methods of operating the same’ (1930).
Pure neon glows red in a vacuum discharge tube. Other colours are produced by different gases or mixtures of gases.
Neon is also used to make high-voltage indicators and switching gear, lightning arresters, diving equipment and lasers: ‘Gas discharge laser having a buffer gas of neon’ (1983).
Liquid neon is an important cryogenic refrigerant: ‘Cryogenic neon refrigeration system’ (2003). It has over 40 times more refrigerating capacity per unit volume than liquid helium, and more than 3 times that of liquid hydrogen.
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All patent information has been obtained from Espacenet (European Patent Office).