| 摘要 |
<p>PURPOSE:To obtain a compact coordinate data input device by using >=2 sound wave detectors set on a base board to detect the position of a sound wave generator touching the base board. CONSTITUTION:The sound wave detectors S1-S4 are set on a liquid crystal panel 9, etc., and a sound generator 10 is brought into contact with the surface of the panel 9. Thus the pulse type sound waves are produced. Then the time required for the sound waves to reach detectors S1-S4 are measured so the distances between the generator 10 and detectors S1-S4, that is, the coordinates are obtained. In this case, >=2 detectors suffice and >=3 detectors are desirable for reduction of the errors of measurements. The positions of the generators can be tracked continuously with periodical generation of sound wave pulses. The piezoelectric materials like crystal, etc., are used to the generator 10 and detectors S1-S4. In such a way, the sound waves are simply detected with no parallax owing to those detectors S1-S4 set the edge positions on the glass surface of a liquid crystal panel, etc.</p> |
