RealD Glasses and the polarized effect.

  • Thread starter Codfish
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In summary, you can see 3D movies with polarized glasses by tilting the lens. The reflective surfaces in your environment (TV, lamps, mirror, iPod case) all contain some level of polarizing ability and this is what allows you to see the 3D effect.
  • #1
Codfish
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Well I recently watched Avatar in 3D.

Fascinated, I took the glasses home as a memoire of the first 3D movie I have seen.

I kept the glasses on and then took them off to observe. I understood that in order for you to see things in 3D, you would need at least two projectors, one with a polarizing lens tilted clockwise, another in the opposite direction for the other projector.. etc.

Out of sheer randomness, I flipped my 3D glasses over, looked through one eye through one side/lens and began tilting it. I did this in front of my LCD screen and noticed that if I tilted it a certain degree(seemed like 45 degrees), my entire screen would become blank to that one eye. Removing the lens from my eye stopped this LCD blackness.
I understand this occurred because of the polarizing lens inside of the monitor.

Then I glanced at my lamp, then at my old Memorex TV(it has a VCR player built in, just so you know how old it is). I would tilt the lens, but to no avail. I tilted it the other way, again, nothing new happened.
Then, I noticed something in the corner of my eye. My empty plastic iPod case had some of the light reflected on it, and it so happened to be in my field of vision. I tilted the lenses and to my amazement, the light being reflected on it dimmed. I glanced at the lamp, and tilted the glasses: no dim. I glanced at the TV, and tilted the glasses: no dim.
I checked the same thing on all surfaces: wall, golden headboard trimmings, polished & shiny wood, sunglasses, even fingernails.

I then discovered that all reflective surfaces contain a polarizer to some degree.
Why is this? Why is it that I look at the TV, tilt the glasses, and I don't see any dimmage, but when it's reflected onto another surface I see dimmage?

Thanks, & it's great to be apart of this forum.
 
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  • #2
Hi Codfish, welcome to PF,

You are absolutely correct, reflected light is (partially) polarized. This is the effect that makes polarized sunglasses better than non-polarized sunglasses (your 3D glasses are not sunglasses). Next time you are out driving with sunglasses, tilt your head and notice that the glare off the windshields in front of you increases at 45º.
 
  • #3
There are actually two distinct easily visible sources of polarized light:

1) Reflection off of dielectric (non-metallic) surfaces. This is due to reflection at Brewsters angle. See
http://en.wikipedia.org/wiki/Brewster's_angle

2) Blue-sky polarization. The visible light from a very clear blue sky at 90 degrees from the Sun is 100% polarized. This is due to Rayleigh scattering. See
http://farside.ph.utexas.edu/teaching/em/lectures/node97.html

Bob S
 

Related to RealD Glasses and the polarized effect.

1. How do RealD glasses work?

RealD glasses use circular polarization to create a 3D effect. Each lens has a different polarization angle, which allows each eye to see a slightly different image, creating the illusion of depth.

2. Can I use RealD glasses for regular movies?

Yes, RealD glasses can be used for regular movies as well. However, since the movie is not specifically made for 3D viewing, the polarized effect may not be as noticeable.

3. Do RealD glasses work on all screens?

No, RealD glasses are designed to work with digital 3D screens. They will not work on traditional film projectors or non-3D digital screens.

4. Can I reuse RealD glasses?

Yes, RealD glasses can be reused. However, they are typically designed for a single-use and may lose their effectiveness after multiple uses.

5. Can I wear RealD glasses over my prescription glasses?

Yes, RealD glasses can be worn over prescription glasses. However, it may cause discomfort or distortion in the polarized effect. It is recommended to wear contact lenses for the best viewing experience.

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