Page 1 of 1

[REQ]Turning regular LCDs into polarized 3d displays

Posted: Thu Mar 08, 2012 5:54 pm
by passingby
Hello MTBS3D,
http://hackaday.com/2011/11/25/making-a ... n-old-lcd/
What's the potential of turning this privacy hack into a 3d one by use of specialized display driver and polarized glasses?

From what I understand, LCD monitors have two sets of polarized filters. One can have it's polarity rotated electrically and the other one is fixed. If the rotation angle required for going from bright to near black is small enough and if the liquid crystals are capable of a large enough angle, then the extremes of the maximum angle could be used for the images sent to both eyes.
If the maximum angle is small or the fade angle is large, then that reduces the number of usable colours, or worse, gives inverted image for each eye.

Re: [REQ]Turning regular LCDs into polarized 3d displays

Posted: Thu Mar 08, 2012 8:39 pm
by cybereality
This seems interesting, but would you need to sandwich two LCD panels to do this (ie one for each eye)? Otherwise how are you getting 2 distinct images?

Re: [REQ]Turning regular LCDs into polarized 3d displays

Posted: Fri Mar 09, 2012 3:27 am
by passingby
I was hoping at least by just using the brightness at the cost of color reduction. That is, if the maximum rotation angle for the LCD polarizer is large enough.
And I'm guessing sandwiching two LCD panes wouldn't work because they are going to block each other out. Unless maybe you get the first LCD to display alternating images for both eyes at different polarization angles and get second LCD to do full oscillations(90 degrees would be ideal) at refresh rate frequency. That complicates things a bit, requiring extra electronics and the potential murder of two monitors. It's also possible that the second LCD doesn't have sufficient response time to execute full rotation of polarization at refresh rate.

Re: [REQ]Turning regular LCDs into polarized 3d displays

Posted: Fri Mar 09, 2012 9:03 am
by Likay
The actual lcd-panel is totally transparent and can't block light even if it's polarized. The panel will however alter the characteristics of already polarized light and turn linear polarization into circular (rotation decided by the state of the polarizing panel). If you use circular polarization before the polarizing panel the final result will be linear polarization. About using two random lcd-monitors as you describe (like a z-screen) it'll only work if the panels are fast enough. I doubt any lcd's that aren't pure 3d-monitors are.

Re: [REQ]Turning regular LCDs into polarized 3d displays

Posted: Fri Mar 09, 2012 4:20 pm
by passingby
I was expecting the LCD panel to be a linear polarizer.

Re: [REQ]Turning regular LCDs into polarized 3d displays

Posted: Fri Mar 09, 2012 7:33 pm
by Likay
Nope. The actual lcd-panel acts like an adjustable retarder. Therefore they're always combined with polarizers.