Display device having reduced reflection of visible light

A display device comprising:

• a display panel having spaced apart first and second substrates facing each other, with a plurality of image displaying pixels provided on one of the substrates and configured for displaying a potentially changing image in a visible light band;
• a plurality of optical sensors provided in the display panel and configured to sense light in one or more predetermined light bands;
• a polarization film provided in the display device and configured to substantially transmit light polarized in a first direction and to substantially absorb or otherwise block light polarized in a second direction, where the second direction is substantially perpendicular to the first direction;
• and
• a polarization-changing wave plate disposed in the display device above the polarization film and oriented to face the polarization film such that first polarized light that has once passed through the polarization film and then next passes a first time through the polarization-changing wave plate has its respective polarization changed by the polarization-changing wave plate to thus become second polarized light and such that if the second polarized light is reflected to pass a second time through the polarization-changing wave plate, the second polarized light has its respective polarization changed by the polarization-changing wave plate to thus become third polarized light that is polarized in a polarization direction that is rotated by about 90 degrees relative to the first direction so that the polarization film therefore substantially absorbs or otherwise blocks the reflected third polarized light from passing through the polarization film.