STF (Switchable Transparent Film) is a light modulating material comprised of droplets of liquid crystal uniformly dispersed in a transparency or translucency, flexible plastic film.
When power off, coming visible light scatters through the STF and the film turns translucent; When power on, coming visible light transmits the STF and the Film turns clear

The polymer and the liquid crystals are encapsulated in the STF. Both faces of the film are covered with a transparent, ITO coating. Both ITO coatings are connected to a flat electrical busbar, which is fixed on one of the edges of the film.

When the Film is switched off from its power supply, the liquid crystals are randomly scattered and diffuse light in all directions. In this state STF is translucent and prevents both sides from seeing through the Flim.

By switching the Film on, the crystals line up and reorientate themselves, turning the Film totally transparent. Switching from the non-transparent state to the transparent state is almost instantaneous and can be repeated as often as desired.

STG(Switchable Transparent Glass)is a laminated glazing comprising two sheets of glass, either clear or tinted, and a STF. The STF and the glass panes are assembled by means of two interlayer films (exp EVA film)