COORDINATE INPUT DEVICE, DISPLAY DEVICE COMPRISING COORDINATE INPUT DEVICE, AND COORDINATE INPUT METHOD

摘要

A coordinate input device (1) comprises: at least one transmitting antenna (2) which transmits radio waves, which are spread spectrum modulated by pseudo noise code, toward an object which a user either approaches or contacts on a display window; at least three receiving antennae (3a-3c) which may be combined with the transmitting antenna (2) and which receive reflected waves from the object; and a detector unit (12) which detects the position coordinates of the object. For each of the receiving antennae (3a-3c), and based on the propagation time from the transmission of the radio waves to the receiving of the reflected waves, the detector unit (12) derives the sum of the distance between the transmitting antenna (2) and the object and the distance between the receiving antennae (3a-3c) and the object, and furthermore, detects the position coordinates of the object based on the sum thus derived.