Cordless position detection apparatus
Patent 5557076 Issued on September 17, 1996. Estimated Expiration Date: 
November 14, 2014. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
November 14, 2014. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesCoordinates input apparatus Digitizer system with passive pointer Wireless coordinate reader and switch state detection system for coordinate indicator Phase reference system for cordless looping digitizer Half normal frequency regime phase encoding in cordless digitizers Patent #: 5373118 InventorsAssigneeApplicationNo. 339699 filed on 11/14/1994US Classes:178/18.03, Writing digitizer pad178/20.02Electrical filter or multiplexerExaminersPrimary: Chin, StephenAssistant: Loomis, Paul Attorney, Agent or FirmForeign Patent References
International ClassG08C 021/00Foreign Application Priority Data1993-11-12 DEAbstractA cordless position detection apparatus includes a position detection area and a pointer. A plurality of conductors are arranged side-by-side in the position detection area. The position detection area has a selection circuit for selecting single conductors, and a transmitting circuit that provides a transmitting signal having at least one harmonic to a selected conductor. A pointer for use with the position detecting area includes a resonance circuit which is tuned to an harmonic of the transmitting signal. The pointer is excited by the transmitting signal to oscillate and radiates a receiving signal. A receiving circuit in the detection apparatus detects the receiving signal in a selected conductor and processing means uses this received signal to determine a position indicated by the pointer.Other References
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