Electrically sensitive writing tablet - works with electric pen using capacitative change in wire grid to represent graphic data for telecommunication

摘要

The writing tablet incorporates an electrical pen (7) with a tip (8) which when pressed against the tablet causes a capacitative change of the order of oil to be made by the pressure of the pen. The pen is cable connected to the tablet which has a central panel (5) of paper over a cover plate, beneath which is a grid of wires of 32 x 32 matrix size. The polarisation effect of the electric pen improves the resolution and permits up to 512 x 512 points to be represented. In addition, a number of circular apertures (g-1,g-2,...g-k) are available for control signals. The system enables graphic information to be transmitted along telecommunication lines.