PURPOSE: To efficiently detect an X coordinate by applying voltage pulses to X electrodes in a specific pattern and successively converging a position area in contact with a detector.
CONSTITUTION: During a vertical blanking interval coordinate detection circuit 111 supplies data for applying voltages to the X electrodes x0 to xm-1 in the different patterns for respective line periods through a selector 112 to an X electrode driving circuit 103. That is, the X electrodes x0 to xm-1 are successively equalized into line period number multiples 2 and the voltage is applied to the X electrode of the area on a very right side and the X electrodes of every other present area from the area. For instance, the detection voltage of a pen 104 in contact with the X electrode x2 becomes a voltage level higher for the voltage applying pulse of an (N-1)-th line period (m=2N) and detection data become '1'. By making the detection data and bit data successively correspond to each other in the coordinate detection circuit 111, it is detected that the X coordinate is 2.
FURUHASHI TSUTOMU
MANO HIROYUKI
NISHITANI SHIGEYUKI
TAKITA ISAO
TSUNEKAWA SATORU
HAMADA TATSUZO
KITAJIMA MASAAKI
SUZUKI TETSUYA
HITACHI VIDEO & INF SYST
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