| 摘要 |
<p>PURPOSE:To surely detect an instructed position even when a material such as water and oil exists on a panel by detecting the instructed position with a stylus pen based on the maximum value of an electrostatic induced voltage detected with the stylus pen. CONSTITUTION:Electrodes 12 are arranged in a grating condition on a panel 11, and to the electrodes 12, a constant voltage is impressed from an electrode driving circuit 13 activated with a measurement start instruction from a host side from edges. The electrostatic induced voltage obtained by instructing the position on the panel 11 by means of a stylus pen 14 is given to an amplifying circuit 15. A comparing circuit 17 compares the output of an LPF 16 with a threshold voltage, and a maximum value detecting circuit 18 detects the maximum value of an output voltage to exceed the threshold value from the LPF 16. A time detecting circuit 19 detects a time since the prescribed voltage is impressed from the origin of the electrode 12 until the maximum value of the output voltage of the LPF 16 is detected. A converting circuit 20 obtains the instructed position (coordiantes) by the stylus pen 14 based on the data from the time detecting circuit 19 and transfers it to the host side.</p> |
