A polarizer includes an opening defined in the polarizer and through which light transmits; a non-opening which is adjacent to the opening and blocks the light; a plurality of metal lines elongated in a first direction, and separated from each other in a second direction different than the first direction, in the opening; and a plate-type pattern in the non-opening. A height of the metal lines is smaller than a height of the plate-type pattern, from a same reference; and an interval in the second direction and between adjacent metal lines is smaller than a wavelength of visible light rays.