HOWTO: Use old active shutter on regular LCD monitors!

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graydini
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HOWTO: Use old active shutter on regular LCD monitors!

Post by graydini »

Ok I just discovered this hack that I really wish I would have known 4 years ago, and don't know if anybody knew this.
I found out how to use those old Active Shutter glasses from Razor, eD, and/or x3d, on regular none-3d lcd panels (yes the ones that only do 60hz-72hz refresh), it is most definitely not as good as crt, and the parallax settings are not forgiving but it works! YMMV

Ok, so as some of you may have noticed, if you try to use the old style active shutters on an lcd panel, you will likely see a black screen. This is due to the polarization of the panel from what I have read. But did you know that when you add polorizing filters to already blocked light it cancels out the blocked light and it as if nothing is polarized? So how do we cancel the blackout effect on our active glasses?

<TL DR>
Simply wear a pair of real3d glasses (the kind you get free with your movie theater 3d movies) over your active shutters and you can see the monitor perfectly clear! If I remember correctly these are the of the "circle" polarization type. It cancels out the blackout effect of the shutters, and lets them function almost normally. It does not work well with interlieved mode, but it does work reasonably well with alternating (pageflip?) content. I used Bino to watch Avatar 3d with this. You'll have to play with the left/right swap, and the paralax has to be set to 0 in bino, but it does work!

I also found out by accident that an hp dv9700 laptop screen will work with active shutters(the trick of course is to activate them since it's a laptop screen, but this is accomplished by hooking up the dongle to an external monitor).

Please try this out and let us know your experiences, if you have lcd's that are not 3d but do support higher refresh rates I'd really like to know if this works for you.
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cybereality
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Re: HOWTO: Use old active shutter on regular LCD monitors!

Post by cybereality »

Interesting trick. I remember getting as far as using the second CRT monitor but then the image was black on the screen so I gave up. Another LCD screen I tried (Samsung HDTV) didn't have the polarization issue but could not keep a sync (would randomly be 3D for a few seconds then flip wildly). Its definitely not that case that every LCD panel will work, cause a lot of people here have tried and failed. But it seems to work better than myself and others have thought in the past.
graydini
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Re: HOWTO: Use old active shutter on regular LCD monitors!

Post by graydini »

cybereality wrote:Interesting trick. I remember getting as far as using the second CRT monitor but then the image was black on the screen so I gave up. Another LCD screen I tried (Samsung HDTV) didn't have the polarization issue but could not keep a sync (would randomly be 3D for a few seconds then flip wildly). Its definitely not that case that every LCD panel will work, cause a lot of people here have tried and failed. But it seems to work better than myself and others have thought in the past.
I found it does not work with interleved content worth anything, and it's defiantly YMMV, but if you have alternating(I'm not sure if page flip is the correct term or is that nvidia specifc?) better than anaglyph.

I tried awhile ago with a CRT projection hooked up like you tried with your lcd and had the sync problem. But oddly enough my hp dv9700 doesn't have the sync or polorization issue, so it works ok, that's why I decided to try this.

Believe it or not I just picked up a free 37" HD CRT, and in my opinion it blows away the new LCD 3d I've seen at the stores with these shutters. I just wish I could get higher than 60hz, but I can't set the resolution lower than the 800x600 max(running vista, tv says it will do 640x480 @72hz but vista won't go that low). Avatar looks amazing.
WiredEarp
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Re: HOWTO: Use old active shutter on regular LCD monitors!

Post by WiredEarp »

Surely the flicker @ 60hz is ridiculously bad?

I have a 23" CRT @ 120hz, its nice, but my 3D monitor is definitely brighter and better, although the ghosting is slightly more.
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Likay
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Re: HOWTO: Use old active shutter on regular LCD monitors!

Post by Likay »

I'm not sure. In the past i made a lot of tests with lcd's, the nvidia stereodriver vs + the ed-activator without success. Worth noting is that all the lcd's (samsung syncmaster, iz3d and lcd-projectors) i tried with are quite old and that could very well be why i was not successful with any of them. Even at the lowest refreshrates the screens just teared/flashed with absolutely no sense of 3d. I did not have the polarizationproblem (lcd's polarization interfering with the e-d glasses) with any of them though.
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graydini
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Re: HOWTO: Use old active shutter on regular LCD monitors!

Post by graydini »

yes all of my stuff is very old too. I tested on my LCD projection tv (sony) and it did not work, but I was using the Razor3d small 3d box for those old b/w movies they sell, hooked up through composite. So I haven't got to try it on any good input yet.
I know for sure, that interpolated content does not give the effect. But if you can do the full frame swapping back and forth, it is at least something.
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cadcoke5
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Re: HOWTO: Use old active shutter on regular LCD monitors!

Post by cadcoke5 »

Note that the following comment comes from someone talking outside of real expertise.

I do know that there is a type of film called a "retarder" that can change the polarization of a light. It is a way to change the orientation of the polarization. I don't know if the retarder is the same for linear vs. circular polarization.

Also, it is possible that different LCD technologies use circular and some linear polarization.

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Likay
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Re: HOWTO: Use old active shutter on regular LCD monitors!

Post by Likay »

The basic element of a retarderfilm is a quarterwave retarder. It's used to change linear polarization into circular and vice versa. A halfwaveretarder is two quarterwaveretarders stacked onto each other.
The basic element of a polarizer is a linear polarizer. When combinated with a qw-retarder and proper orientation you will have a circular polarizer.
All lcd tv's/monitors in their original shape emitts linear polarized light. The orientation varies and can be 0 or 45°. In order to make these into interleaved 3d-monitors the manufacturer applies a u-pol retarderfilm with the alternating pattern that suits the monitor. The result for passive 3d-monitors will then be circularly polarized and is the reason why probably all passive 3d-monitors/tv-sets are circular polarized.

This trick with a retarderfilm works well because the linear polarized light from the lcd is transformed into circular before reaching the first polarizer of the shutterglasses. To be entirely correct a halfwave retarder should be used but is in my experience totally unnecessary. Circular polarized light goes easily through a linear polarizer.

I'm not an expert but maybe i at least helped to mess it up even more.
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