| 摘要 |
<p>PURPOSE:To stably and accurately detect the tip coordinates of a detection pen even if a noise due to the frictional electrostatic charging of the detection pen is detected during a coordinate detection period. CONSTITUTION:A coordinate detecting circuit internally has a comparator which converts the induced voltage signal from the detection electrode of the detection pen into a binary signal. The tip dielectric of the detection pen and the input panel of a liquid crystal panel use such a pair of materials that the polarity of the frictional electrostatic charging of the tip dielectric is the same as the polarity of the slice voltage 'e3' of the comparator. Thus, the polarity (plus) of a misdetection signal induced at the detection electrode owing to the discharging of the frictional electrostatic charging is made opposite from the polarity (minus) of the slice voltage 'e3' to remove a misdetection signal component mixed with the induced voltage signal from the detection electrode. Consequently, even when the noise due to the frictional electrostatic charging of the detection pen is detected, the tip coordinates of the detection pen can stably and accurately be detected.</p> |
