The Orientation
Touchscreens

The Orientation: Touchscreens

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This week we’re going to take a closer look at what Devin thinks is just a fad. Touchscreens seem to be invading all sorts of devices from cell phones to TVs more so now than ever before. They’re meant to improve our lives, or, at the very least, make things more convenient. But do they? How do they even work? Will one form or another of the technology last? Surely, Devin is wrong. This and more in this edition of The Orientation.

There are close to a dozen different flavors of touchscreens, but we’ll be focusing on two of the bigger variations: resistive and capacitive. It might actually help to define each word itself before delving into the technologies behind each. Resistive is a technical adjective that’s defined as having the ability to withstand the action or effect of something. Capacitive is a noun that’s defined as the ratio of the electric charge transferred from one to the other of a pair of conductors to the resulting potential difference between them. They might not help now, but as we get along the definition could clear things up or I could just be filling my column with unnecessary wordage. Heh.

Resistive touchscreens are mechanical sensors that consist of two layers of materials, which are separated by air or spacers. The bottom layer is usually made from glass, which is then covered with a conductive and resistive metallic layer. Pressure from your finger on the top layer makes contact with the bottom layer where the voltage at the contact point is measured and location computed along the X-Y axis. There seems to be a debate over which type is most durable. While some argue that a resistive touchscreen’s top layer can be stretched out or deformed over time you may want to consider it’s affordability and they’re not as affected by severe scratches the way capacitive touchscreens are. On another note, it only permits 75 percent of light from the monitor, which sucks when compared to a capacitive system allows up to 90 percent. The argument could last all day, really, but I’ll leave that up to you folks. You’ll find this type on just about every touchscreen surface you encounter on a daily basis. Think grocery stores kiosks.

A capacitive system is covered with a layer that stores an electrical charge and when you apply pressure with your finger or stylus the reference state is altered and the position of the change is registered based on the number of circuits between each corner of the panel. Because this type is based on electrical charges, you don’t necessarily have to apply that much pressure because it picks up even the slightest change as if you were hovering or gliding your finger across the plane. This type is most evident on the iPhone.

I realize there isn’t a whole lot of in-depth detail here and some of it might sound vague, but most of my sources for this week’s column essentially said the same thing with varied word vomit. This is meant to be a brief overview of some of the common types available to the masses today. As the technology grows, which it’s bound to do, we’ll delve further into it. But chances of us getting another go around on these types is highly unlikely. Multi-touch is the wave of the future and I’m not talking about the iPhone’s variation of it. Multi-touch has been around for almost three decades and was popularized, and I use that term loosely, by FingerWorks in the 90s with their Gesture Pads, which Apple subsequently bought out. Do I think touchscreens are fads? No. Do I like them in their current form? Absolutely not. Let’s see where the next couple generations of multi-touch go.

Thanks to Synaptics for some background info

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