A spatial light modulator (70) comprised of an array of micromirrors (72) each having support post (74). The support post (74) defines support post edges (76) in the upper surface of the mirrors (72). These support post edges (76) are all oriented at 45 degree angles with respect to an incident beam of light from a light source (80) to minimize diffraction of light from the edges (76) into the darkfield optics when the mirrors are oriented in the off-state. The present invention achieves an increased contrast ratio of about 20% over conventional designs.