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?
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There are polarized particles in the glass that change orientation when they receive an electrical voltage through the edge of the panel. When the voltage changes, they reorient themselves and block some of the light.
They’re LCD screens without the reflective part. There is a polarization filter and the liquid crystal. When the polarizations are aligned it lets light through. You can control the polarization of the liquid crystal by applying a voltage. The greater the polarization mismatch the more of the light that is filtered and the darker the window.
It’s the same idea to taking two polarizing filters and rotating them relative to each other. Instead of mechanically rotating one filter you adjust the molecules with an application of electricity to change the polarity.
There are polarized particles in the glass that change orientation when they receive an electrical voltage through the edge of the panel. When the voltage changes, they reorient themselves and block some of the light.
There’s a film applied to the window that has a layer of liquid crystals sandwiched in-between two pieces of plastic.
When the film is turned ‘off’ the liquid crystals can do whatever they want which creates opaqueness in the window as they’re all just scattered about.
When you turn it ‘on’ a current of electricity is run through the film which causes all the liquid crystals to snap into alignment and become clear.
[It’s called PDLC film.](https://www.youtube.com/watch?v=ZT9kKs1X9_g&ab_channel=DavidWatts)
There are polarized particles in the glass that change orientation when they receive an electrical voltage through the edge of the panel. When the voltage changes, they reorient themselves and block some of the light.
There’s a film applied to the window that has a layer of liquid crystals sandwiched in-between two pieces of plastic.
When the film is turned ‘off’ the liquid crystals can do whatever they want which creates opaqueness in the window as they’re all just scattered about.
When you turn it ‘on’ a current of electricity is run through the film which causes all the liquid crystals to snap into alignment and become clear.
[It’s called PDLC film.](https://www.youtube.com/watch?v=ZT9kKs1X9_g&ab_channel=DavidWatts)
They’re LCD screens without the reflective part. There is a polarization filter and the liquid crystal. When the polarizations are aligned it lets light through. You can control the polarization of the liquid crystal by applying a voltage. The greater the polarization mismatch the more of the light that is filtered and the darker the window.
It’s the same idea to taking two polarizing filters and rotating them relative to each other. Instead of mechanically rotating one filter you adjust the molecules with an application of electricity to change the polarity.
There’s a film applied to the window that has a layer of liquid crystals sandwiched in-between two pieces of plastic.
When the film is turned ‘off’ the liquid crystals can do whatever they want which creates opaqueness in the window as they’re all just scattered about.
When you turn it ‘on’ a current of electricity is run through the film which causes all the liquid crystals to snap into alignment and become clear.
[It’s called PDLC film.](https://www.youtube.com/watch?v=ZT9kKs1X9_g&ab_channel=DavidWatts)
They’re LCD screens without the reflective part. There is a polarization filter and the liquid crystal. When the polarizations are aligned it lets light through. You can control the polarization of the liquid crystal by applying a voltage. The greater the polarization mismatch the more of the light that is filtered and the darker the window.
It’s the same idea to taking two polarizing filters and rotating them relative to each other. Instead of mechanically rotating one filter you adjust the molecules with an application of electricity to change the polarity.
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.
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