This is a great tutorial on what polarization is all about and how it works. Quite honestly it’s the best example I’ve seen of precisely how today’s polarization glasses work. Anybody thinking of installing a RealD or similar polarization 3D digital cinema system should be watch this first so they know a little bit more about the technology.

We’d demonstrated all this to the kids – but why does one of the pairs of realD glasses have to point backwards in order to block the light? There’s a moment in your video when you can see what happens if they point the same way – light through both sides. That stumped us embarrassingly fast, so how does it work?

I am no expert on this but form my understanding there are different layers/coatings involved in a Polarised glass.. The light needs to pass through the different coatings in a certain order. As such, the polarised glass only works correctly when light passes through it a certain way.
I think you can double coat the glass as well so they work both directions. However as the 3D glasses are only suppose to be used in a certain way, to save costs, they are not double coated for both directions. Saves in production costs too.

I suggest you hit google and look for information on polarised material, there are many.

Hope that helps.

hello, I’m new to this but wanted to buy the 3d glasses Chinese
3d polarized as shown in your video and wanted to make a
questions about them, would work on my computer LCD monitor? would work on my laptop? projecting 3D movies.