When researching the different types of touchscreen technologies, you’ll probably comes across capacitive and resistive. These are, by far, the most common types of technologies used to power touchscreen devices. Capacitive devices sense touch commands by measuring capacitance, whereas resistive devices sense touch commands by contact between two or more layers. While capacitive and resistive remain the most popular types of touchscreen technologies, however, surface wave acoustics (SAW) is becoming a popular alternative. So, what is SAW touchscreen technology exactly?
Overview of SAW Touchscreen Technology
SAW touchscreen technology is unique in the sense that it uses ultrasonic waves to sense touch commands. Touchscreen devices powered by this technology are designed to produce sound waves that travel across the surface of the screen. The perimeter of the device is affixed with reflectors that bounce off these sound waves. When you touch the surface of the screen, you’ll disturb the sound waves, which the device detects as a touch command.
The sound waves produced by SAW devices aren’t loud. In fact, you won’t be able to hear them at all. However, SAW devices are still capable of “hearing” these sound waves — and that’s essentially how they work. SAW devices constantly emit sound waves while simultaneously looking for disruptions. If a disruption is detected, the device will register the location of the disruption as a touch command.
Benefits of SAW Touchscreen Technology
SAW touchscreen technology offers several benefits, one of which is longevity. Because they sense touch commands using sound waves, there’s no real hardware inside the device that can break down or otherwise stop working.
Second, SAW touchscreen technology is very sensitive to touch commands. With resistive devices, you must press down hard enough on the display surface for the upper layer to come into contact with an underlying layer. If you don’t press down hard enough, it won’t sense your touch command. This isn’t an issue with SAW devices, however, as they sense touch commands on the surface using sound waves.
Third, SAW touchscreen technology supports the use of a stylus. Resistive touchscreen technology also supports the use of a stylus, but this isn’t something you’ll find with capacitive technology. Since styluses aren’t conductive, they don’t work with most capacitive devices. But they will work with both resistive and SAW devices.
The bottom line is that you shouldn’t assume capacitive and resistive are the only available touchscreen technologies. Whether you’re purchasing a tablet computer, human machine interface (HMI) or any other touchscreen device, SAW is definitely worth considering.