| 摘要 |
<p>PURPOSE:To detect a coordinate indication by a stylus pen and a finger, by switching arbitrarily detections of an electrostatic induction voltage between the stylus pen and each detection line, and between the detection line to which a voltage is applied and its adjacent detection line. CONSTITUTION:When a terminal S3 and S2 of a selector 11 are connected, coordinates of an indicated position by a stylus pen are detected. Also, when the terminal S3 and S1 of the selector 11 are connected, switches 8a, 8b... are opened and closed successively by a driving circuit. A switch of a detection line being adjacent to a detection line in which a switch is in a closed state is set to a closed state by a driving circuit. When an operator's finger is on a glass surface 6 or in its vicinity, the electrostatic capacity between a detection line 7a and 7b is varied from C0 to C2. Therefore, an output voltage E1 of a sense amplifier 10 becomes like an expression I. (Where K is an amplification factor of the amplifier 10). By detecting this voltage E1 by a voltage detecting circuit 11, a detection of an indicated position by a finger can be executed.</p> |
