Patent ID: 6888538

Claim:
A hand-held portable battery-powered data processing device comprising: a freely movable stylus comprising an electromagnetic resonator; and a housing comprising: a memory for storing data; a display for displaying data within an X-Y display area to a user; a user interface via which the user can manipulate the stored data using said stylus; a main processor operable to receive data from the user interface and to control the operation of the device to effect the desired user manipulation of the stored data; and a power circuit operable to receive energy front a battery and to provide power to said memory, display, user interface and the main processor; wherein said user interface comprises: a base mounted substantially parallel to and overlapping said X-Y display area and carrying: (i) an excitation winding for receiving an excitation signal and for generating an electromagnetic field to cause said electromagnetic resonator resonate when said stylus is in the vicinity of said base; (ii) an X sensor winding which extend is substantially over the whole X-Y display area and which is operable to output a signal that varies with the relative X position between the stylus and the X-Y display area when said electro magnetic resonator resonates in the vicinity of said base; and (iii) one or more Y sensor windings which are arranged substantially over the whole X-Y display area and which are operable to output signals that vary with the relative Y position between the stylus and the X-Y display area when said electromagnetic resonator resonates in the vicinity of said base; an excitation circuit operable to receive energy from said battery and operable to generate said excitation signal for output to said excitation winding; and a position processor operable to process the signals from said X and Y sensor windings to provide position information of said stylus relative to said X-Y display area to said main processor.