[REQ] [DIY] LCD Shutterglasses for $20?

Post by **nubie** » Fri Apr 11, 2008 2:26 pm

Is there a possibility that shutterglasses could be made for near zero ghosting for LCD's?

I am thinking that instead of using the 2 polarizing filters on the LCD in the shutterglasses, use one (or none?) and have it aligned with the monitor's front polarizing layer (as far as I know you only need 4 angles, 0°, 90°, 45°, 135°, or you could make the LCD flippable and only make two models, one diagonal, and one orthogonal)

This way the brightness goes up when it is off (clear), and when on it is blocking the polarized light from the monitor very efficiently.

Anybody see anything I missed?

Deal on shutter glasses, $10 + $10 shipping ($30 shipping outside of the US)
http://forums.nvidia.com/index.php?showtopic=64472

http://www.xforce3d.com/

If you could strip the polarizing filters off of this and then rotate them until they blocked your LCD, it just might work.

Thoughts?

Post by **sharky** » Fri Apr 11, 2008 2:37 pm

should work.. but you would have to place the lcd glass itself at -45 and +45 degrees, and remove teh polarizing foil from teh glass.. but ti would be VERY sensitive to head movement.. (i think...)

Post by **nubie** » Fri Apr 11, 2008 2:46 pm

2 points:

1. I don't think it will be any more sensitive than my Planar rig (that is to say very very good, and only goes away if your head leans very far over. 45° is clear 10-15° is about like standard shutter glasses, who plays with their head sideways? *)

2. It should be much darker than any CRT shutterglasses, no ghosting when it is on.

*I agree that this wouldn't be the setup to have for a head tracking system, did you see that tracking gun I posted?

Post by **Freke1** » Fri Apr 11, 2008 4:58 pm

I don't know anything about LCD's, but isn't the way they refresh the reason they don't work with shutterglasses?

Post by **LukePC1** » Fri Apr 11, 2008 4:59 pm

I don't get you... What do you want to do?
Do you want to change polarization of the monitor with about 100hz? Or is the refreshrate of 75 or 85hz enough?

Post by **sharky** » Sat Apr 12, 2008 1:07 am

im afraid freke is right.. the refresh of the lcd's is sthe problem.. they dont change the image fast enough in bright locations..

Post by **LukePC1** » Sat Apr 12, 2008 10:08 am

I didn't see Frekes post...

Well I read somewehre (here) that the picture is not fully visible at a certain time. If you have the wrong time, the next picture is already shown half.

It's a combination of delay and bad building of the picture.
A crt needs time to start again from the top, but the LCD doesn't need this time...

Post by **nubie** » Sat Apr 12, 2008 10:25 am

I thought that it was because the phosphors in a CRT fade very fast (near instant, that is why there is a flickering), and LCD's had a much longer drop off in brightness because they changed state much quicker.

With the newer screens sporting overdrive pixels and the like, maybe it is quick enough for this kind of tech?

I was just thinking of ways to stick with LCD, get full resolution per eye, and fix the ghosting issue with shutterglasses all in one blow, but there are technical hurdles, that I will grant you.

Post by **Tril** » Sun Apr 13, 2008 11:21 am

There's also the problem of the visible flicker of the glasses if their frequency is not high enough. I'm talking about putting on the glasses and looking around (not at the screen) while they are activated. My experience is the following :

At 60 Hz, I see them flicker a lot.
At 75 Hz, I still see them flicker.
At 100 Hz, I start to see the flicker less but it's slightly visible.
At 120 Hz, the flicker is totally invisible.

Post by **LukePC1** » Sun Apr 13, 2008 1:10 pm

nubie wrote:I thought that it was because the phosphors in a CRT fade very fast (near instant, that is why there is a flickering)[...]

If the phospor was that quick, there wouldn't be any ghosting. A DLP has nothing 'glowing', so there is no real ghosting - just a shift in colors depending on the speed of the color-weel