Touchscreen devices are all around. From tablet computers and smartphones to human machine interfaces (HMIs) and automotive infotainment systems, countless devices support touch-based commands. And while there are a variety of technologies used to achieve this, the most common is capacitive. With that said, not all capacitive touchscreen devices are made equal. Some use a special type of technology known as projected capacitive. So, what is projected capacitive touchscreen technology, and how does it work exactly?
Understanding Projected Capacitive Touchscreen Technology
Both standard (surface) and projected capacitive touchscreen devices identify touch commands by measuring change in capacitance. They create a uniform electrical charge that runs through the device’s layers. Upon touching the interface, the user’s finger absorbs some of this voltage, thereby allowing the device to identify the precise location of the user’s touch.
Projected capacitive touchscreen devices work on the same basic principle. However, there are a few features that make them unique. The upper glass layer, for example, features transparent electrodes — typically aligned in a grid-like fashion — that project an electrostatic field. Upon touching this layer, the user absorbs some of the charge. This phenomenon allows the device to determine when and where the user touched.
Benefits of Projected Capacitive Touchscreen Devices
Why should you choose a projected capacitive touchscreen device instead of a traditional surface capacitive device? They are both excellent choices that can be used in a variety of applications, but projected capacitive technology offers a few noteworthy benefits over its surface capacitive counterpart. For starters, the display is typically clearer with projected capacitive devices. Second, this technology usually supports multi-touch commands, meaning you can control them using two points of simultaneous contact. Most importantly, projected capacitive touchscreen devices can be used while wearing thin gloves.
Surface capacitive and projected capacitive are just two of many touchscreen technologies. It’s also worth mentioning that resistive technology is a common method used to create touchscreen devices. Unlike surface and projected capacitive, resistive technology doesn’t identify touch commands by measuring change in capacitance. Rather, they identify touch commands through pressure. As a result, they can be used with a bare finger, gloved finger or stylus. The downside to resistive touchscreen devices, however, is that they typically don’t last as long as capacitive devices. This is why most companies prefer either surface or projected capacitive touchscreen devices instead of resistive.
