A display device comprising: a display panel and an optical system over the display panel, wherein the optical system comprises: a first panel comprising a plurality of first electrodes extending in a first direction; a second panel facing the first panel and comprising a plurality of second electrodes extending in a second direction crossing the first direction; a liquid crystal layer between the first panel and the second panel; and a first insulating layer between the first electrodes and the second electrodes, the first insulating layer including an organic material, and a first driver configured to apply a common voltage (Vcom) to the plurality of first electrodes in a multi-view mode and to apply a touch input voltage to the plurality of first electrodes in a touch mode; and a second driver configured to apply different voltages to adjacent ones of the second electrodes in the multi-view mode and to receive a touch output voltage from the second electrodes in the touch mode; such that the first electrodes and the second electrodes form a touch sensing capacitor configured to sense a touch in the touch mode, and the first electrodes and the second electrodes apply an electric field to the liquid crystal layer in the multi-view mode, the electric field depending on a voltage difference between the first electrode and the second electrode, to generate different phase delays according to positions along the optical system. a display panel and an optical system over the display panel, wherein the optical system comprises: a first panel comprising a plurality of first electrodes extending in a first direction; a second panel facing the first panel and comprising a plurality of second electrodes extending in a second direction crossing the first direction; a liquid crystal layer between the first panel and the second panel; and a first insulating layer between the first electrodes and the second electrodes, the first insulating layer including an organic material, and a first panel comprising a plurality of first electrodes extending in a first direction; a second panel facing the first panel and comprising a plurality of second electrodes extending in a second direction crossing the first direction; a liquid crystal layer between the first panel and the second panel; and a first insulating layer between the first electrodes and the second electrodes, the first insulating layer including an organic material, and a first driver configured to apply a common voltage (Vcom) to the plurality of first electrodes in a multi-view mode and to apply a touch input voltage to the plurality of first electrodes in a touch mode; and a second driver configured to apply different voltages to adjacent ones of the second electrodes in the multi-view mode and to receive a touch output voltage from the second electrodes in the touch mode; such that the first electrodes and the second electrodes form a touch sensing capacitor configured to sense a touch in the touch mode, and the first electrodes and the second electrodes apply an electric field to the liquid crystal layer in the multi-view mode, the electric field depending on a voltage difference between the first electrode and the second electrode, to generate different phase delays according to positions along the optical system.