3D LCD display

Before I start, I apologise for posting what I already know to be a fully-baked idea - but it's not a well-known idea and the instructions here will let anyone build a neat piece of kit that's fun to use.

By the way I built this back in 2001 and sat on it thinking I would patent it. An exhaustive patent search at the time showed no prior art. But I was too lazy and never did the paperwork, and now I've seen at least two of these home-brewed at exhibitions in the last year or two. That's my only justification for entering this as a half-baked idea, because like most of my hobby projects it never went past the prototype :-)

One of the earliest 3D displays was Edwin Land's system (US Patent No: 02084350 from 1935) with two TV tubes and two sheets of polarizing film, plus a semi-silvered mirror. The displays are placed 90 degrees to each other with the mirror at 45 degrees between them so they overlap when viewed through polarized glasses.

My design is to use two LCD flat panels, and *no* polarizing filter, because the panels are already polarized. And fortunately almost all flat panels are polarized at about 45 degrees (actually nearer 39 but it's close enough for this to work) so when placed at 90 degrees to each other with the semi-silvered mirror between them, by a wondrous piece of luck they are almost perfectly cross-polarized.

Back in 2001 I mailed the authors of several 3D graphics drivers and asked them to support this format (one of the displays needs to be mirror inverted - either horizontally or vertically, it doesn't matter - just rearrange the panels and the mirror to suit) and much to my surprise several of them did so, so you ought to find it relatively easy to make a home-brew system like this work.

The glasses you use are the standard passive ones as used at old-style (pre shutter-glass) IMAX cinemas. They're easily obtainable from Stereophotography vendors.

Any two-headed VGA card will work, like the very old Matrox I used in 2001, or cheap modern cards like the GEForce 5500 which can be had for $50.

I'ld love to see a new generation of arcade games use this technology. Many stand-up arcade boxes already use a 45 degree mirror to conserve space with large glass monitors. They'd be easy to tweak into using a semi-silvered mirror and two flat panel LCD displays.

Graham