Patent attributes
Keypad apparatus for registering signals corresponding to data that a user enters by pressure on keys of an array in a surface extending in two dimensions. The elements of first and second sets of impedance elements (R) are connected in series through respective interconnections and a signal processor applies first and second reference signals across the first and second sets of impedance elements respectively. User pressure on the keys makes or breaks connections through corresponding contact elements between a respective pair of the interconnections, one from the first set of impedance elements and one from the second set of impedance elements, so as to generate first and second output signals (PX1, PY1) that together are a corresponding combination of the first and second reference signals that is unique to the actuated key elements.
