Method and apparatus for inputting coordinates

A coordinates input apparatus in which by indicating an arbitrary point on a vibration transmission plate by a coordinate indicating device for generating a vibration, coordinate values at said arbitrary point are detected, comprising:

• a plurality of detecting means, arranged at predetermined positions in the vibration transmission plate, for detecting the vibration which is generated by the indication by the coordinate indicating device, for converting the vibration into electric signals, and for outputting;
• measuring means for measuring delay times from a time point when the indication has been performed by the coordinate indicating device until time points when the electric signals are detected;
• obtaining means for obtaining origin correction data a plurality of number of times from a predetermined position on the vibration transmission plate;
• memory means for storing the origin correction data;
• and
• calculating means for reading out the origin correction data from the memory means, for correcting the coordinate values on the basis of the delay times measured by the measuring means and the origin correction data, and for calculating the coordinate values.

A coordinate input method comprising:

• step 1 of detecting a vibration by vibration sensors, said vibration being transmitted to a vibration transmission plate by a coordinate indicating device for generating a vibration;
• step 2 of measuring delay times from a time point when the indication has been performed by the coordinate indicating device in said step 1 until time points when the vibration is detected by the vibration sensors;
• step 3 of obtaining origin correction data from a plurality of points on the vibration transmission plate;
• step 4 of storing the origin correction data derived in said step 3 into a memory;
• and
• step 5 of reading out the origin correction data stored in the memory in said step 4, correcting the coordinate values of the vibration input position in said step 1 on the basis of the delay times measured in said step 2 and the origin correction data read out, and calculating the coordinate values.