Capacitive is the world’s leading touchscreen technology. It powers everything from smartphones and tablets to human machine interfaces (HMIs), monitors and more. It’s known as “capacitive” because it measures capacitance to detect touch commands. With that said, not all capacitive touchscreens are the same. There are several different types of capacitive touchscreens.
Also known as a surface capacitance touchscreen, a surface capacitive touchscreen features an insulator layer with a conductive coating on one side. A uniform electrostatic field is applied to this insulator layer. Touching or tapping the display interface with a conductive object will disturb the electrostatic field. The voltage of the electrostatic field will change in the area of the touch, which the surface capacitive touchscreen will register as a touch command.
Another common type of capacitive touchscreen technology is projected capacitive. Projected capacitive touchscreens offer a superior level of accuracy, responsiveness and resolution when compared to surface capacitive touchscreens. They are designed with high-tech processing units that allow for improved touch performance.
Mutual capacitive touchscreens are a type of projected capacitive. They receive their namesake from the way in which they register touch commands. Mutual capacitive touchscreens recognize a touch command by looking for a charge that’s created when two conductive surfaces are close together. All conductive surfaces and objects form a charge when they are close together. Mutual capacitive touchscreens use this phenomenon to detect and register touch commands.
They have conductive traces running vertically and horizontally. When you touch or tap the display interface with a conductive object, a capacitor will be created at the intersection nearest to your touch command. The mutual capacitive touchscreen will then register your touch command in that area.
Like mutual capacitive, self-capacitive is a variant of projected capacitive touchscreen technology. They work in the same way as mutual capacitive touchscreens. Self-capacitive touchscreens look for a charge created by two conductive surfaces, such as the top layer and your finger. The difference between mutual capacitive and self-capacitive touchscreens likes in the operation of their conductive traces.
Mutual capacitive touchscreens have conductive traces that operate dependently of each other. In comparison, self-capacitive touchscreens have conductive traces that operate independently of each other. In turn, self-capacitive touchscreens are typically more accurate than mutual capacitive touchscreens. The downside is that they often fail to offer multi-touch technology, meaning you can only make one contact with the display interface at any given time.