| 摘要 |
<p>PURPOSE:To prevent the check of processing efficiency by providing a storing means for a coordinate input valid area and a discrimination means of a valid area, and executing no input of a coordinate value in case an input coordinate value is out of the valid area. CONSTITUTION:Piezo-electric elements (sensor) 6 for detecting an elastic wave transmitted through a propagation material 8 are arranged on peripheral parts S0, S1, S2 of the material 8. The coordinates of the position P(x, y) of an indication point obtained through a clock counter 18 or the like can be found out from the position P(x, y) and straight distances d0, d1, d2 between respective sensors 6. Namely, oscillation is detected by oscillation waveform detecting circuits 12-14 and the coordinate value of the indication point can be calculated from the distances d0-d2 obtained as the detecting results. Whether the calculated coordinate value is included in the inside or outside of an effective area previously stored in a ROM 20 is decided through a control device 1 or the like, and when the value is included in the effective area, the coordinate value is outputted, and in case of the outside, the coordinate value is not outputted. Since a host device is not forced to execute useless processing, the interruption of processing efficiency in the host device can be suppressed.</p> |
