Materials Used to Build Multitouch Screens Matter to Multitouch Designers

Touch screens we are most familiarize with BiP (before the iPhone) are resistive. Thats what they use at McDonnalds and your ATM. The iPhone introduced projected capacitive screens to the masses, but the question is what's the difference?

This article at Embedded.com does an excellent job of explaining the differences and the reason why projected capacitive screens are coming into favor over resistive screens.

Why is this important? Well, the materials used to manufacture multitouch screens has a direct impact on the gestures and interactions multitouch designers can use with those systems.

Both resistive and projected capacitive screens rely on a rare material called Indium Tin Oxide (ITO) which is expensive produce and, as its discussed in this article by NanoMarkets, is likely to be userped by less expensive easier to obtain materials.

Finding alternatives to ITO will change the way that multitouch screens are manufactured and the way we use multitouch devices depends in large part on how they are made. You cannot simply invent multitouch gestures and interactions will-nilly and expect them to work on all types of multitouch hardware. Technical limitations of the materials used to create multitouch screens have a direct impact on the gestures and features available.

For example, multitouch in resistive screens has been difficult to achieve and until the introduction of Stantum's resistive screens were pretty much written off as a multitouch implementation technology. Projected capacitive screens on the other hand cannot detect variances in presure - not yet. Hacks like the Blackberry Storm's clickable-screen get around that somewhat, but they tend to be clunky compared to resistive screens ability to detect varity degrees of presure.

The bottom line is that no matter what we want to do in terms of gestures and interactions, we will always be constrained by the materials used to produce multitouch screens. Keeping this in mind as a designer is critical to making good design decisions. This is especially true with multitouch platform like Windows 7 which are bound to be deployed on many different devices that use different multitouch technology.