Autogating of image intensifier tubes consists of automatically regulating voltages to the tube’s microchannel plate to optimize brightness and protect the tube in significantly changing light conditions. When it was discovered that the development of filmless image intensifier tubes (provisionally termed “Gen 4”) was not practical, tube manufacturers developed very thin-film ion barriers to protect the photocathode while increasing tube performance.

These thin-film tubes combined with autogated power supplies provide the current state of the art of image intensification technology. In 2001 the US Army declared that the term “Gen 4” would no longer apply to filmless tube technology, resulting in the US military’s current use of “thin-film, autogated” image intensification tubes as the standard for its night vision devices.