Coordinate input device and display device including the same

A display apparatus comprising:

• a display panel that displays an image based on an image signal from an external system;
• and
• a coordinate input device disposed on a display surface side of the display panel,
• wherein the coordinate input device includes
• a coordinate input unit in which a plurality of first detection electrodes and a plurality of second detection electrodes intersecting the first detection electrodes are formed, and which is disposed on the display surface side of the display panel,
• an electrode drive circuit that applies a drive signal to one or more of the first and/or second detection electrodes,
• a capacitance detection circuit that detects a capacitance of the first and/or second detection electrode in synchronization with the drive signal,
• means for selecting one or more of the detection electrodes to which the drive signal is not applied from among the detection electrodes which are disposed in parallel to the detection electrodes to which the drive signal is applied, as a reference electrode,
• means for detecting a capacitance of the selected reference electrode,
• means for correcting a capacitance detection result of the capacitance detection circuit on the basis of the detected capacitance of the reference electrode, and
• an input coordinate computing circuit that calculates an input coordinate from the corrected capacitance detection result.