Coordinate input method and apparatus using elastic wave.

摘要

Coordinate input method and apparatus are disclosed. The coordinate input apparatus comprises a transparent input tablet (1) which is laminated on tablet-like display face (10) of the display unit and has a plurality of elastic wave detectors (2a to 2d) mounted thereon. When any position (P) on the input tablet is pressed with an elastic wave input pen (3); an elastic wave emitted from the input pen and propagated through the tablet is detected by the detectors to measure propagation times (T1 to T4) of the elastic wave to the respective detectors. A coordinate computation circuit (8) determines coordinates of the any press position of the input pen on the basis of the measured propagation times and supplies the coordinate information to the display unit for display thereon. Prior to the determination of coordinates of the any press position, two reference point (P0, Q0) on the tablet are pressed with the input pen to compute data of deviation of a coordinate system of the display face with respect to a coordinate system of the tablet. The coordinates of the any press position of the input pen are determined in a form in which the derivation between the display face and tablet coordinate systems is compensated by means of the computed deviation data.