A display device and a mobile terminal including the display device are discussed. The display device can include a display panel including a first pixel area and a second pixel area, a cover glass disposed on a first surface of the display panel in the second pixel area, an optical module disposed under a second surface of the display panel to face the second pixel area and configured to direct infrared light towards a light transmitting part of the second pixel area, and a diffractive optical element disposed on or in at least one of the cover glass and the display panel at a position corresponding to the light transmitting part of the second pixel area. The diffractive optical element can separate the infrared light from the optical module into a plurality of dot beams.