Touchscreens are all the buzz. With the prevalence of tablets and smartphones, consumers assume every screen is now an interactive station with touch capability.

And we know that when you get someone to participate by touching a screen, the chances of them retaining the message or buying the products increase dramatically. 

For integrators not playing in the interactive space, it can be rather confusing to know why or when to specify one product over another. Without further ado, here is a quick look at the types of touchscreen technology available.

Resistive Touchscreens: This is the oldest of the bunch and the most basic. Layers of conductive material are placed over the screen and electrified. When someone touches the screen, the layers are compressed, getting close to one another and changing the electrical field.

Resistive touch has traditionally had some life cycle issues past 1 million touches (although now, many tout higher cycles). These are also traditionally single-touch devices - think of the ATM you use, as it is most likely resistive. The layers are a little cloudy as well, changing the colors and clarity of the screen somewhat. Resistive touchscreen can work with a stylus and a gloved hand. 

Capacitive: These screens also have multiple layers, but instead of relying on compression to facilitate the electrical impulse, they rely on a path to ground, namely, a person. These screens typically have a higher duty cycle. Gloved hands and traditional styli cause issues. You have to have an electric stylus to use these screens that can facilitate a ground point. Again, these are traditionally single- or dual-touch devices as they use electrical devices at the corners to calculate position. They too obscure the screen somewhat but have less layers than do resistive screens. 

Surface Wave: This technology goes by quite a few names - APR, SAW, etc. - but the concept is the same. Sensors pick up vibration waves in the surface of the glass.  As it is not electric, a stylus or gloved hand works fine. Since it measures the surface of the glass, this technology will not ignore items placed on the screen or palms resting against the glass. This can cause some issues, especially in tabletop installations. Because the sensors are mounted to a single piece of glass, clarity is increased. These are typically single- and dual-touch devices.

DST: This technology echoes the aforementioned with one important distinction: it measures the vibrations on the back side of the glass. This means it can reject static objects, like palms or drinks, setting on the table and still recognize touches. DST is also more durable than the previous three technologies, as damaging the surface of the touchscreen does not greatly affect function as it does in resistive, capacitive, and surface wave devices. DST will support some Windows 7 multitouch gestures.

Projected Capacitive: Think iPad. These screens create an electric field just like traditional capacitive screens. But since they are not relying on electrical impulses generated at the corners only, projected capacitive devices are much more versatile and support unlimited touches.

Again, this requires a path to ground, so gloved hands and basic styli do not work. They do make capacitive gloves as well as styli.

The next three technologies are really non-touch technologies, as you really don’t have to touch the screen to trigger them. This can be confusing to users if not calibrated closely to the surface, as they can inadvertently interact with things on the screen just by getting their fingers close to the surface.

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About the author

Mark Coxon - Sales, Mark

Mark started his technology career at IBM in 2000 before migrating into AV integration in early 2002. He currently works at Horizon Display, an interactive multitouch hardware and software provider. Mark lives in Orange County with Lesley, his wife of 11 years and his 3 children.

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