Display device with touch panel

Abstract

Provided is a display device with a touch panel having the cost thereof reduced without a decrease in the transmittance ratio of light. A substrate has a planar transparent conductive film formed on an observer side thereof. The transparent conductive film is used as a transparent electrode of an electrostatic capacitance coupling type touch panel. A position detection pulsating voltage production circuit that inputs a pulsating voltage for position detection, and a coordinate position arithmetic circuit that computes a touched position on the transparent conductive film touched with an observer's finger are included. The transparent conductive film is shaped to have four corners. The position detection pulsating voltage generation circuit applies the position detection pulsating voltage to each of the four corners of the transparent conductive film at different timings. When the position detection pulsating voltage is applied to one of the four corners of the transparent conductive film, the coordinate position arithmetic circuit computes the touched position on the transparent conductive film, which is touched with the observer's finger, on the basis of a voltage outputted through the corner diagonally opposite to the corner to which the pulsating voltage is applied.