Provided in an illumination device including a display panel including a first surface configured to display an image, a second surface opposite to the first surface, a plurality of display pixels disposed between the first surface and the second surface, and a transmission window configured to transmit light incident on the second surface through the first surface, a light source disposed at the second surface of the display panel and configured to emit light to an object toward the display panel, and a light deliverer disposed between the light source and the display panel, the light deliverer configured to deliver the light emitted from the light source to the object as flood illumination through the transmission window.