How do the new airplane windows that turn dark using a button work?

Question

I was on a flight recently that had the dimmer style windows instead of the old style where you would just pull down a shade. I wondered how the glass could be made to go darker or lighter at the push of a button?

In: 24

Answer 1

It’s got a LCD film in it.
When energised the crystals in it align and it becomes opaque.

The mirrors in my car have the same film and will automatically darken at night to stop any chance of getting blinded by reflected headlights.