LIGHT TRANSPARENT TYPE FAST TOUCH INPUT DEVICE

PURPOSE:To detect touch input at high speed, to improve a system by performing fine scan again centering a position detected by coarse scan, and to detect the position of touch input with high accuracy and at high speed by performing the coarse scan and the fine scan. CONSTITUTION:A sequence generation circuit 7 generates sequence in which light emitting elements in directions of row and column are driven by the instruction of a control circuit 9, and the sequence is sent to a light emitting element driving circuit 8, and the light emitting element driving circuit drives designated light emitting elements in the directions of row and column. A shielding position detection circuit 6, when shielding being detected from a light receiving element column, detects the positions in the directions of row and column, and sends them to the control circuit. The control circuit 9, when no light shielding being detected, sends a signal to the sequence generation circuit so as to drive at least every other optical device by the signal from the shielding position detection circuit.