Transparent Touch Screen

2016-02-23 17:14

Last year I did a small evaluation project with Texas Instrument's Light Crafter DLP3010EVM, that features there DPL3010 chip and all the electronics you need to drive it.

While the DLP chip itself is quite tiny (~8mm across for the 1280x720 resolution DMD),

with all the illumination, optics and electronics you need, I'm afraid it gets a little bit to bulky for an AR-glass project or a Jolla dlpTOH.

So I found somthing else to do for it.

A Screen made of Glass

Did you see Corning's "A Day made of Glass"?

What an inspiration!

Let's build it!

The first problem to solve:
If you project your image on a normal window, the light goes right through it.

Of course, that is what windows are made for!

Unfortunately that means there is not much to see of the image.

We need to coat the window with something that will makes the image visible.

So I bought some foils, that are especially designed for this purpose.

You can get them in different shades, from about 95% transparent (top), translucent, light gray, dark gray.

I would really love to get my hands on a black and even mirror(!) sample, but they are much harder to come by.

Which one to choose, depends on you application.

translucent (top) vs. transparent foil

Another great idea is:
You can cut shapes out of the foils. The picture will only appear on the foiled part of the glass and leave the rest blank.

For my experiments I bought some cheep picture frames and glued the foils on the glass (the foils have gule on one side already).

Touch me!

Projecting a picture is already nice, but making the experience interactive puts the cherry on the cake!

There are different ways to do that, but if you want a solution that, works:

you go for a capacitive touch digitizer.

We all know and love them from our tablets and telephones. But in all honesty, 12" are just not big enough!

The solution is a Capacitive Touch Digitizer Foil.

Right now my sources have them up to 100 inch (yes, one hundred!).
That's 2.54m.

This one too, comes with glue on one side.

Let there be light!

Now we have all the parts together, let's have some fun!

I built a little rack, that allows me to freely combine all the screen foils with the digitizer foil and positions the DLP3010EVM projector correctly.

First a demo, that I put together for a guy that owns car dealership (hence the theme :-):

And here the transparent screen, with Windows 7 set to a black desktop:


I would recommend to use an Ultra Short Throw projector, instead of the classical setup.

This way:

I made a few quick calculations and some sketches for a 60 inch screen design, based on a Ricoh PJ WX4141.

Looks like that thing would still fit quite nicely on a table (measurements are in mm - Of course!).

Imagine a trade show booth, where you DON'T:

BTW, if you're advantures try the online 3D CAD view (WARNING! Might contain traces of Cookies and External JavaScript! WebGL).