ELIMINATION OF ENVIRONMENTAL INTERFERENCE TO A CAPACITIVE TOUCH PAD BY A DUMMY TRACE

摘要

A capacitive touch pad includes a sensor layer for sensing a touch of an object and a dummy trace below the sensor layer. The dummy trace is sensed to obtain a sensed value while the dummy trace is shielded by the sensor layer from interference of the object such that the sensed value reflects only environmental variation. Therefore, environmental variation can be identified depending on the sensed value, and the sensor layer can be calibrated properly.