How touchscreen works

    

    There are different types of touchscreen, of the most popular are the resistive and conductive types. The way this technology works makes it quite hard to replicate it in diy sense. But still, it is quite a fascinating technology.

pic: How resistive screen works

Resistive Touchscreens

    These are currently the most popular type of touchscreens. Imagine them as “transparent keyboards” overlaid on top of the screen. They consist of two layers, a flexible upper layer made of conducting polyester plastic and a rigid lower layer made of conducting glass. These layers are separated by an insulating membrane.

    When you press on the screen, the top layer touches the bottom layer through tiny holes this completes an electric circuit, similar to pressing a key on a keyboard. A chip inside the screen calculates the coordinates of your touch.

    Resistive touchscreens are commonly used in smartphones, e-book readers, and some laptops. The easiest way to see the difference is that on resistive screens, unlike the capacitive ones, you can use even a nonconductive object, like a plastic pen or a wood pencil. 

pic: Layers of a capacitive screen

Capacitive Touchscreens

    These are widely used in modern smartphones and tablets. The surface of a capacitive touchscreen is coated with a grid of electrodes.

pic: Connector of the capacitive screen to both layers.

pic: Traces behind the black frame around screen.

    When your finger touches the screen, a capacitive contact is formed. An alternating current (AC) is generated within the device, inducing a corresponding current within your body, this helps complete the circuit, and the device detects your touch. Capacitive touchscreens are more responsive and can handle multi-touch gestures.

    There are other technologies like infrared touchscreens, surface acoustic wave touchscreens, and optical touchscreens. Each works differently but achieves the same goal - detecting your touch without obstructing the view of the screen.