Patent ID: 6535200
Filing Date: 2003-03-18
Classification: G06F

Abstract:
A capacitive sensor for sensing a position of an object adjacent a sensing region comprising a portion of a resistive layer having a sheet resistivity of at least ten Ohms per square, the sensor comprising:a selected number, greater than one, of electrodes contacting the resistive layer and spaced apart about a periphery of the sensing region so that none of the electrodes extend within the sensing region; the selected number of charge detectors, each charge detector respectively associated with one of the electrodes; means for transferring electrical charge from a voltage source to at least one of the electrodes so as to charge the resistive layer to a selected voltage; and the selected number of charge transferring switches, each of the charge transferring switches respectively associated with one of the electrodes, each of the charge transferring switches having a closed state in which it electrically connects the electrode associated therewith to a respective charge detector, each of the charge transferring switches having an open state in which it does not connect the electrode associated therewith to the respective charge detector associated therewith, and wherein each of the charge detectors has a respective output.