Repolarizing lcd monitors question

[WheatstoneHolmes]

Anyone know is this http://www.polarization.com/polarshop/p ... ucts_id=28 would change the polarization of an LCD monitor?

Thanks!

[Likay]

Yes it's possible. You'll get even better results if you're using using a halfwave (90°polarizationtwist) retarder in combination with above polarizer. One single quarterwave gives almost unnoticeable result compared with a halfwave.
If you're not too eager about light intensity and only want to twist the polarization 45° you may skip the retarder and use only polarizer. You can't turn polarization 90° with a single polarizer though. Even if you're about turning polarization only 45° i suggest also using retarder because: they're very much cheaper than polarizing film, and the extra light (+30-40%) throughput they give is truly worth it.

[WheatstoneHolmes]

Thanks Likay!

[cirk2]

what exactly is the difference between a polarizer and an retarder?

I ever thought that polarizing is done by sending light throu a "comb". Does a retarder something else?

[Likay]

A retarder is a transparent foil which also interferes with polarized light. It doesn't block polarized light in any means just "rotate" it. It's like a comb where the fingers are longer and twisted. You cannot block light with a retarder though.
It needs to aligned properly as well to have the right function.

You can make your own circular filter by stacking a rightful aligned retarder followed by a polarizer. In a matter of fact this is the way professional filters are made as well (circular polarizers are a 2-layer construction).
Circular polarizers are around in our everyday lives as well. Polarized camerafilters nowadays always uses circular polarizers and same with newer polaroidglasses (after the 80's if that can be called "new"...).
SPAR-filters (made especially for lcd-projectors and passive projection for high light throughput) for instance are made of approximately 15 layers of carefully aligned retarders followed by a polarizer. I tried to build one filter myself out of curiosity but with no good result. You need a good transparent nondepolarizing glue, most probably a vacuumchamber and a patience of a snail travelling around the earth...

If you're building a passive rig i cannot recommend using circular polarization for the simple reason that circular ghosts quite a bit more than linear (Obs: When using circular pol. the polarizers for the projectors needs to have the polarizer closest to the projectorlense, then followed by the retarder). The argument that you're able to turn your head more using circular polarization is not valid since you need to keep your head somewhat straight to maintain proper stereo anyway. Try with shutters or anaglyph.

Not a physic explanation here since i simply don't understand what happens on a electromagnetic level anyway.

[cirk2]

Not a physic explanation here since i simply don't understand what happens on a electromagnetic level anyway.

No problem was enough information for me.

About the glue: Can't you take a drop of water? or is it depolarisizing...

[Likay]

I don't know. Made a few experiments though. Don't worry.. i had fun doing this. o.O
I put a polarizer in "blocking" angle in front of the screen and put some objects in between thus finding out their depolarizing properties.

Half waterfilled etching tank. 3 glassplates of about 5mm's each with water in between. (in other words: Neither water or glass used in this depolarizes light)


Plastic emty cd-case.


Emty cd-"spider". Swedish for "spindel" which is spider. Don't know the english word for it...


Plastic wrapping.


Have pfun.

[cirk2]

Wow that CD case looks someway beautiful

When water isn't depolarising you should be abel to mount a polarizer with it...

Thanks for the experiments

[Likay]

No problems. (pops back into the drawer)