In an embodiment, a display panel unit includes a reflective polarizing layer, a transparent layer, and a display panel. The polarizing layer transmits a first polarized component of light incident on an incident surface to an exit surface and reflects a second polarized component of the light. The transparent layer transmits the first and second polarized component of the light incident on a second surface to a first surface adhered to the incident surface and transmits the second polarized component reflected by the polarizing layer to be incident on the first surface to the second surface. The panel faces the exit surface, and selectively transmits the light exiting from the exit surface.