Hello everyone,

I’m new here, but I hope to contribute to the forum by learning and later teaching about Multi-touch technology.

Anyway, I’d like to start by making a LCD FTIR setup, as it’s a cheap start, and if successful, we’ll go from there. I had a few questions I would like to ask; firstly as I scanned the forums, I found a few confusions concerning the backlighting. Some say it emits IR light, others say they don’t. Please en-lighten me (haha). Secondly, I’ve seen some discusions removing a certain filter layer between the LCD Matrix and the “honey” cone layer. Would that have something to do with IR filtering or is it unnecessary?

I also have a question about compliant surfaces, which I will post in the correct section.

Thanks for your help.

You probably won’t know until you take apart yours and try it out ... unless you can find someone using the exact same monitor as yours.  Odds are that it can be solved by either window film or using a good bandpass filter and tweaking your software settings.  Mine does emit IR but with two layers of window film it is completely gone.  It also decreases the brightness, but it’s not horrible.  And there’s always the option of building a couple of rails of LED lighting which doesn’t emit IR to increase the brightness.

Hope this helps!

I check out your Elemental Multitouch Project, and it seems your putting the backlight behind the camera, or beside it. Putting a IR Filter over that would certainly work. But I was hoping to leave the backlight directly under the matrix. Doable?