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AssigneeFujitsu Limited
InventorsJames A. Kriewall, Edwin F. Johnson, Alan R. Selfridge, John P. Fairbanks, Verne H. Wilson, Robert W. Parry, James D. Cummins
Estimating the term…
A digitizer uses acoustic waves originating from a stylus to determine the position of the stylus on a plate. The acoustic waves are introduced into the plate from the tip of the stylus and are detected by a plurality of detectors positioned at various points along the periphery of the plate. By sensing differences in the arrival times of the acoustic waves at the detectors, a microprocessor calculates the position of the stylus. In a preferred embodiment using a non-tethered stylus, four detectors are positioned at the corners of a rectangle, and the time differences are used as addresses in a lookup table, which is programmed to contain x and y coordinates corresponding to the time differences, Different embodiments may detect only the "fast" symmetrical waves or only the "slow" antisymmetrical waves generated in the plate, or may use the arrival times of both types of waves to determine the stylus position.
A device for providing a digital representation of the location of a stylus on a plate, said device comprising:
The device of claim i wherein said acoustic waves are Lamb waves of the symmetrical mode.
A device for providing a digital representation of the location of a stylus on a plate, said device comprising:
A method of generating an electrical signal representative of the position of a stylus on a plate, said method comprising the steps of:
Dependencies are inferred from the claim text.