A digitizer is a device that converts the movements of a digital stylus/pen on a smartphone/tablet PC into digital signals. As the S Pen support for the Galaxy Note series is comparable to a real pen with its level of accuracy and precision, the term ‘digitizer’ has become more widely known.

A digitizer consists of a signal detected substrate and a pen that transmits electromagnetic signals using the electromagnetic induction method. The substrate is able to detect changes in the electromagnetic emission of the stylus when you actively move it around.

Intricate details can be captured with this technology as the substrate is able to detect the pen’s distance, height, and position while the thinness of the stylus allows for the precise input of coordination information.

▲ Digitizer integrated into Galaxy Note (Source: Samsung Electronics Newsroom)

The sensor substrate that detects the electromagnetic field is produced by forming an electrical circuit on a thin plate, generally through a series of processes such as exposure, developments, and etching — similar to how a display is manufactured. A finalized sensor substrate is placed below a display panel, which then adds another layer of cover window on top.

Contrary to a digitizer, a touchscreen panel (TSP) - which is a capacitive input device - is attached on top of or built into the display panel.