An aspect of the present invention provides an optical filter that includes a plurality of slits arranged in parallel, each slit corresponding to a pair of displays including at least a first display of a first image, and a second display of a second image, wherein the slits form a slit row in a horizontal direction arranged essentially in the same interval spacing and parallel to each other, with the slit row arranged with slit pitch patterns that differ by at least between the upper and lower positions.