Why the Golden Raptor? Why are F22 canopies coated with a thin layer of Indium Tin Oxide?
In order to reduce the radar cross-section (RCS) of the aircraft, the F22 canopies are coated with a thin layer of Indium Tin Oxide (ITO), which gives it a golden tint.
The F22 Raptor canopy comprises two sheets of polycarbonate, sandwiched between two layers of optical glass, fusion bonded in an autoclave, and a drape formed over a canopy blank.
A metallic coating of indium-tin-oxide is added to the canopy to reflect the radar waves, giving it a golden tint.
The transparent conducting film of gold or ITO (indium tin oxide) is used as an electromagnetic wave shield as well for stealth aircraft.
Applying such transparent conducting film thus enables while maintaining transparency to visible radiation, both a radio wave stealth property which scatters radio waves in various directions so as not to be detected by radar and an electromagnetic wave shield property which prevents harmful electromagnetic waves, except for visible radiation, from invasion into the aircraft.
They are used in stealth aircraft to reduce the RCS
A window member composed of a transparent resin or inorganic glass with a transparent conducting film such as gold or ITO (indium tin oxide) coated thereon, is used as an electromagnetic wave shield window for stealth aircraft.
This technique is used in other aircraft like the EA6B Prowler.