Patent ID: 7573631

Claim:
A method of operating a micro electromechanical systems (MEMS) based spatial light modulator (SLM), the method comprising: determining a corrected level for an intensity of reflected light by a pixel of the MEMS-based SLM when the pixel is in an ON state; determining an analog voltage to apply between movable ribbons of the pixel and a substrate thereunder such that the movable ribbons are deflected from an undeflected state by an analog distance so as to reduce the intensity of the reflected light by the pixel to the corrected level wherein the movable ribbons deflect between a first position spaced from and substantially parallel to the substrate to a second position adjacent the substrate; controllably setting the pixel in the ON state by applying the analog voltage between the movable ribbons and the substrate; and controllably setting the pixel in an OFF state by applying a snap-down voltage between the movable ribbons and the substrate thereunder, wherein applying the snap-down voltage causes the movable ribbons to undergo a snap-down motion so as to rapidly deflect a top surface of the movable ribbons to a predetermined height provided by standoffs above a top surface of the substrate, the predetermined height less than ⅔ a distance separating the lower surface of the movable ribbons in an unmoved position from the top surface of the substrate and such that a height difference between a ribbon in the undeflected state and a ribbon in the OFF state is approximately an odd multiple of one-quarter of a wavelength of incident light, wherein the standoffs are positioned on a lower surface of the movable ribbons facing towards the top surface of the substrate; and controllably operating the pixel in grayscale mode by applying voltage between the movable ribbons and the substrate to attenuate intensity level of light reflected by the SLM by up to fifty percent (50%).