What Is a Projected Capacitive Touchscreen Device?

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.