Patent ID: 8009152

Claim:
A refined coordinate detection method for a touch panel including a plurality of X-axis infrared emitting and receiving elements and a plurality of Y-axis infrared emitting and receiving elements, the method comprising: measuring and storing a maximum received optical level of a pair of infrared emitting and receiving elements, infrared emission and reception of which is not impeded by an object, and a minimum received optical level of a pair of infrared emitting and receiving elements, infrared emission and reception of which is completely impeded by the object: measuring and storing a received optical level of a pair of infrared emitting and receiving elements placed on a center axis of the object, a received optical level of a pair of infrared emitting and receiving elements corresponding to a left end of the object, and a received optical level a pair of infrared emitting and receiving elements corresponding to a right end of the object: calculating basic coordinates of the object based on the received optical level of the pair of infrared emitting and receiving elements placed on the center axis of the object; and calculating refined coordinates of the object by comparing the maximum received optical level and the received optical levels of the two pairs of infrared emitting and receiving elements corresponding to the left and right ends of the object.