Abstract: With a double-sided display module having a main panel and a sub-panel sharing drive signals, the image quality of the main panel is improved. When the display devices uses the same driver IC to drive the main panel and the sub-panel, the contrast is uneven at the border area between a region of the main panel where signal electrodes share drive signals with the sub-panel and a region of the main panel where signals electrodes do not share drive signals. In order to make the contrast unevenness practically invisible to the naked eye, an unshared electrode adjacent to the border between different contrast levels on the main panel is connected to the dummy electrode. The dummy electrode has to be smaller than the total overlap area of one electrode that constitutes a pixel of the sub-panel. In the case where the sub-panel has more than one dummy electrode, the dummy electrodes are gradually made smaller.