Polarised 3D glasses and an LCD Monitor

In summary, the conversation discussed observations made while looking through a pair of 3D movie glasses at an LCD monitor. The speaker was confused by the fact that both lenses turned the same color at the same time when tilted 45 degrees and that the glasses behaved differently when looked through in the wrong direction. Further reading revealed that the glasses use polarizing filters, but the speaker was still unsure of the reason for these observations. Another participant in the conversation shared their own experience with polarizers and explained that they have a protective film that causes the observed color changes. They also mentioned that the two polarizers in the glasses are aligned at different degrees to send different video channels to each eye.
  • #1
ratata
1
0
Hi,

I was looking through a pair of 3D movie glasses (the polarised sort) while looking at my lcd monitor. I was confused by a couple of things:
- When I tilt the glasses 45 degrees from horizontal, the image in both lenses turned blue, and when i tilted the glasses 45 degrees from horizontal the other way, the image in both lenses turned orange/red. I thought that one lens should be orange/red while the other is blue, not the same colour at the same time.
- When I turn the glasses around so that I am looking in the wrong direction through the lens, and then do the 45 degree tilt as above, both lenses either turn black (no light passes through) or remain clear. I thought that they should behave the same no matter which way you look through them.

I have done a little reading and found that lcd screens use polarising filters but i can't get my head around the above two observations. I hope someone can tell me what is going on!

Thanks for your help.
 
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  • #2
Welcome to the Forum, ratata, and a very interesting observation!
Yes, I observed the same thing when messing with polarizers pulled off a hand-held videogame. What did I find out? I found out that these polarizers (made by mechanically stretching a polymer as it's solidifying) have a protective, transparent film on one side. On the unprotected side, you'll observe black-to-transparent, and on the protected side, you'll see blue-to-red. This is due to dichromism; by the interference of the light through the protective film/polarizer interface.

You may peel the polarizer from its protective film using a hydrocarbon-based solvent.

Both glasses polarizers act in unison as you rotate them, true, but they are aligned the following way: Left lens has its polarizer oriented at 22.5-degrees, and the right lens has its polarizer oriented at 68.5-degrees. This way, both polarizers will block out light in unison as they are rotated, while being oriented by these two, different degrees. As you know, these two different degrees of orientation of the lenses in the glasses (22.5 and 68.5 degrees) are what sends left-channel video (22.5 degrees) to your left eye, and right-channel video (68.5 degrees) to your right eye.
 
  • #3


I can explain the observations you made with the polarized 3D glasses and LCD monitor. The polarized 3D glasses are designed to work with a specific type of 3D technology called passive 3D. This technology uses two images, one for each eye, that are polarized in different directions. The glasses have lenses that are also polarized in different directions, allowing each eye to see only one image. This creates the illusion of 3D depth perception.

When you tilt the glasses 45 degrees from horizontal, you are essentially changing the angle of polarization. This causes the images in both lenses to turn the same color because they are now both polarized in the same direction. This is why you saw both lenses turn blue or orange/red at the same time.

As for your second observation, when you turn the glasses around and look through them in the opposite direction, the images in both lenses disappear or remain clear because the polarization of the glasses is now opposite to the polarization of the LCD screen. This creates a blackout effect, where no light is able to pass through the lenses.

In summary, the behavior of the polarized 3D glasses and LCD monitor is due to the specific polarization technology used in passive 3D. It is important to use the glasses in the correct orientation to properly view the 3D images on the screen. I hope this explanation helps clarify your confusion.
 

Related to Polarised 3D glasses and an LCD Monitor

What are polarised 3D glasses?

Polarised 3D glasses are glasses that use polarised lenses to create the illusion of depth in 3D images. They work by allowing each eye to see a slightly different version of the same image, creating a sense of depth and immersion.

How do polarised 3D glasses work with an LCD monitor?

Polarised 3D glasses work with an LCD monitor by filtering the light from the screen in a way that creates the illusion of depth. The monitor displays two versions of the same image, each with a different polarisation. The glasses then filter out one of the images for each eye, allowing the viewer to see the 3D effect.

Do all LCD monitors support polarised 3D glasses?

No, not all LCD monitors support polarised 3D glasses. Only monitors with a high enough refresh rate and specific polarisation capabilities can properly display 3D images with polarised glasses. It's important to check the specifications of your monitor before using polarised 3D glasses.

Can I use any type of polarised 3D glasses with an LCD monitor?

No, you cannot use any type of polarised 3D glasses with an LCD monitor. The glasses must be compatible with the specific polarisation technology used by the monitor. Using the wrong type of glasses can result in a distorted or non-existent 3D effect.

Are there any health concerns with using polarised 3D glasses and an LCD monitor?

While there are no major health concerns associated with using polarised 3D glasses and an LCD monitor, some people may experience discomfort or dizziness due to the 3D effect. It's important to take breaks and limit the amount of time spent viewing 3D content to prevent any potential eye strain or discomfort.

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