Circular polarization and Read3D glasses

[barryj]

I am trying to understand circular polarization and Real 3D glasses.I am sure that answers will lead to other questions.

Question 1. Are Real 3D glasses merely quarter wave plates with each eye set at 90 deg angles to the other? or..

Question 2. Do Real 3D glasses consist of a linear polarizer followed by a quarter wave plate?

Question 3. What happens when I put two quarter wave plates together, and then rotate them?

 

[A.T.]

 

[barryj]

Excellent diagram and video. Thanks