US Patent 9519088 Micromirror array

A micromirror array according to the present invention is a corner reflector type micromirror array capable of projecting a mirror image of an object to be projected sharply with high luminance. The micromirror array includes a substrate, and a plurality of unit optical elements (quadrangular prisms) formed in an array on the substrate. Each of the unit optical elements is of a protruding or recessed shape perpendicular to the surface of the substrate. The unit optical elements has two side surfaces orthogonal to each other on opposite sides of a corner of the side surfaces, and the two side surfaces are light reflecting surfaces. Each of the light reflecting surfaces is of a rectangular shape such that the ratio of the vertical length thereof as measured in a substrate thickness direction to the horizontal width thereof as measured in a substrate surface direction is not less than 1.5.