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Tue, Jan 8 2013 7:59:29 UTC

What makes a good touchscreen

Touchscreens have become present in many devices, and a lot of technology experts predict that within a few years, all screens will start using touch, on every possible item we can think of. Already, smartphones and tablets have driven the evolution of touchscreen technologies, and the screens we have now are much better than what we used to have just a couple of years ago. But what makes a good touchscreen, and how can you compare them?

A touchscreen is simply a normal screen with different materials used to make the display, along with sensors to detect touch. The early models of touchscreen displays are called resistive and use two thin layers, with a coating between them. Using an electric charge, the second layer can feel when the first one would be pushed down, as an electrical current would pass. These are still used in some applications because they are very cheap to create, but they require the user to actually push down on the screen, and are less responsive.

Modern touchscreens use capacitive panels, which consist of a glass layer with conductive transparent coating applied. Because the human body is also conductive of electricity, touching part of the screen modifies its electrostatic field. Because of this, the resulting quality is much higher, however the drawback is the need for a human contact, so these cannot be used while wearing gloves or by handling a pen.

Recently, newer versions have been developed using in-cell technology, where the capacitors are inside the glass instead of on the other side, which means the screen can be thinner and brighter. Super AMOLED displays are one example of this technology.

But the quality of your touchscreen is not just in the glass itself. The firmware and other software used in the device plays a major part. When the iPhone came out, it quickly became renowned for having a much better touchscreen than other devices. Tests were done and some reports pointed at firmware in the iPhone simply processing the information in a more accurate way.

Another source of issues with touchscreens is noise. If you have a noisy device, or a noisy environment such as a nearby power supply, then your accuracy will go down. The screen is trying to detect a fairly small contact point from your finger, in a device filled with electronics providing their own electrical pollution. Finally, the power applied to sensors also makes a difference. For example, if a phone uses 12 volts to power the sensors, then it will have a better result than one that uses 3 or 5 volts, like most older phones. However, using more power means your battery life will be lower.

There are some tests available out there to find out how good a touchscreen is. For example, Synaptics makes the TouchExplorer app available for Android devices, which has a series of testing functions. There are also physical devices which can detect how good the screen is. At the end of the day, if your device uses the latest technology, with the most powerful sensors, and there is no nearby noise to interfere, you are likely to get the best result.

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