The Nixie tube is a vintage display device which had been used until 70s when it was replaced with LED displays. The complex knowledge of manufacture of Nixie tubes literally died with tube factory’s engineers, glassblowers and machine operators.
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Wikipedia: The early Nixie displays were made by a small vacuum tube manufacturer called Haydu Brothers Laboratories, and introduced in 1955 by Burroughs Corporation, who purchased Haydu. The name Nixie was derived by Burroughs from “NIX I”, an abbreviation of “Numeric Indicator eXperimental No. 1”, although this may have been a backronym designed to evoke a mythical creature.
Hundreds of variations of this design were manufactured by many firms, from the 1950s until the 1990s. The Burroughs Corporation introduced “Nixie” and owned the name Nixie as a trademark. Nixie-like displays made by other firms had trademarked names including Digitron, Inditron and Numicator. A proper generic term is cold cathode neon readout tube, though the phrase Nixie tube quickly entered the vernacular as a generic name.