The differential voltage pen for plasma panels—A light pen substitute

A new hand-held interactive pen for ac plasma panels is described. The pen uses multiple metal plates to detect positional information generated by the regular write/erase voltages in the panel. No optical detector is used. Closed-form field potential equations of a panel line outside the panel are derived. These equations enable the resolution of the pen to be optimized; they are also helpful in pointing out some avoidable troublesome secondary effects. It is shown that a multiple plated probe's resolution is seven times better than that of a single-plate probe. This new pen can achieve resolutions to within 1 cell on panel artworks as dense as 50 lines/cm. Worst case detect time is 100 ms for a one million cell panel. Difficulties and special panel requirement when applied to a panel display product are discussed.