In general, display devices which can be applied to mobile communication terminals called smartphones or tablet computers can be operated by bringing a means for inputting data, such as a stylus or fingers, into contact with a display surface which displays an image. These display devices include in-cell display devices in which a touch detection function is partially or entirely incorporated into a display panel, and on-cell display devices in which a sensor having a touch detection function is provided on the display surface of a display panel.
As the above in-cell display device having a touch detection function, the following structure is known. Sensor electrodes formed of a transparent conductive film such as indium tin oxide (ITO) or indium zinc oxide (IZO) are provided in matrix in the display area which displays an image. A detection circuit is provided so as to correspond to each sensor electrode. Further, the sensor electrodes are connected to the detection circuits by thin metal lines.
However, the conventional display devices having a touch detection function require the same number of detection circuits as the number of sensor electrodes. Thus, it is difficult to respond to increase in the number of sensor electrodes caused by improvement of detection performance or by increase in the size of the display panel.