[WIP] 3D HMD using 8" xga lcd and the magic of cellopha

Post by **ngsmith** » Thu Apr 24, 2008 2:20 pm

I recently ran across a published article on using cellophane to change the polarization of lcd tft displays. I am posting here the link. For all DIY out there that have spare time on their hands, unlike myself, and looking for alternatives to creating cheap 3d displays. I can see this design being used on two cheap 8" hami 1024x768 lcds to create a hmd. If smaller high res lcd's can be attained even better. Anyone with polorized glasses, an lcd screen, and a nearby art/floral store that has clear cellophane gift wrapping can experiment getting 3d on their monitor.
Here is the link:
http://individual.utoronto.ca/iizuka/re ... ophane.htm

Here is a link to ebay 8" lcd (notice they can interpolate to xga):
http://electronics.listings.ebay.com/St ... ngItemList

Enjoy,

ngsmith

Post by **sharky** » Mon Apr 28, 2008 1:40 am

8"? why not a 3D projector?

nice info..

thnx

Post by **Likay** » Mon Apr 28, 2008 2:59 am

True. Cellophane works as a halfwave retarder. You probably need to use an extra polarizing filter. The purpose of the retarder is to twist the polarization before the filter thus enhance the total light throughput. I tried q-w retarders/polarizers with my lcd-projectors but the alignment of the colors makes trouble on me. (Two colors at 0° and the last one at 90°). If i can stand the light loss then one single polarizer in front of the lcd-beamer gives correct colors (aligned 45° of course).

cheers

Post by **LukePC1** » Mon Apr 28, 2008 6:06 am

sharky wrote:8"? why not a 3D projector?

nice info.. thnx

Because it's intended for a HMD

But I'm not shure, if 8" isn't a little big for a HMD. And what about the optics? DO you think it's possible to use it without any optics

If you build it I'm worried about the wieght. Do can you stay below 1kg? - which is quite heavy already.

Post by **ngsmith** » Mon Apr 28, 2008 10:44 am

I think the weight may be the biggest problem. It would have to be balanced correctly to reduce the strain on the neck. The advantage I see with the 8" screens is that they are cheap and other people have found they are pretty easy to remove from their casing thus reducing the weight to just the lcd panel and its vga controller. Just like the commercial HMD's the biggest problem is the high cost of small oled or lcd micro displays. Possibly the touchscreens could be recycled for use in the HMD setup as well.
I have a 3D projector setup and love it but would also love something more immersive and portable. If it can be done with two 8" screens for under $350 that is cheaper than any 3D projector setup.
The linear polorization seems the best option now since Iz3d is spearheading the production of drivers in this viewer mode for all video cards.

Post by **ngsmith** » Mon Apr 28, 2008 11:16 am

Another option besides linear polorization would be planar. This method using the two 8" screens would produce the highest brightness and richest of colors. Although, I am not sure how comfortable a mirror pressed up to your nose will feel after an hour of play.
Here is a link of a simple cheap method of doing this with the lcd's: http://www.crystalcanyons.net/pages/Tec ... ewing.shtm

Post by **LukePC1** » Mon Apr 28, 2008 5:00 pm

Do I get you right? you want to use 2 small lcds for Planar? I don't think that makes sense, since a little bigger one wouldn't be much cheaper - but less portable.

I like the HMD version very much, but don't know if it's practical. Maybe it's possible to make it for both things --> planar and HMD???

Or try HMD and if it doesnt work change to planar

Post by **ngsmith** » Mon Apr 28, 2008 6:03 pm

Sorry Planar is not the correct term, I actually was referring to creating a mirror flipped stereo image as described in the article I mentioned. It does not require any glasses just that the head be positioned in the appropriate position to the plane of the mirror. Since it would be a hmd the lcd's and glass would be mounted to the head thus fixed in a single position. Here is another link showing the geometry behind it: http://www.crystalcanyons.net/Pages/Tec ... -View.shtm

Post by **LukePC1** » Tue Apr 29, 2008 5:43 am

Hi I just tried it with one display (monitor). It works

I like the Idea with the mirror. You could build a 3D HMD from only one display!
Problem could be that you need special Planar-driver to run it

I just noticed, that silver surfaced CD's make a nice mirror, if you can't find a proper one. The advantage of CD's is, they are realy light and cheap