Optical trackpad

An optical trackpad is an input device based on an optical sensor, which detects the displacement of a finger that is moving on top of it. The sensor is used typically in smartphones where it replaces the D-pad. The main advantages over a D-pad are:

• It can track movements in 360 degrees and with varying speeds.
• It uses space efficiently, without the need for small buttons that are difficult to press.

Next to browsing through menus, it can drive a mouse cursor in point&click interfaces.

In comparison with trackpads, it detects actual skin displacement, instead of displacement of the center of the area being touched.