The Tablets work on the principle of sound and its speed through which the position of the pointer on the screen will be decided. It makes use of flat surface on which we are writing with a stylus. The stylus tip is covered with material called ceramic. It makes sound when writing on the flat surface.
The flat surface is having powerful strip microphones on two sides. These microphones will receive the sound generated by the stylus while writing. Based on the actual time of sound generated and sound received by two microphones will decide the position of the pointer on the screen. In case of 3D acoustic Tablet three strip microphones are used to along the sides of the flat surface and one vertically on their intersecting point