Capacitive Tablet with Coded Drivers to Eliminate Triangular Plates
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
A digitizing capacitive tablet has groups of wires in the x dimension and in the y dimension, as in U. S. Patent 3,999,012. The location of a pen (or stylus or cursor) on the tablet is defined for each dimension by the identifying number of the group of wires and by the identifying number of an adjacent wire within the group. As in the tablet of the patent, a set of driver transistors each drive one wire in each group of wires and the location of the pen within a group can be found by shifting the pattern of activation of the wires until the wires to one side of the pen are activated and wires to the other side are not activated.