The present invention provides an optical micromirror device and their array device and method for making the same. By introducing a sub coating layer and an over coating layer with a high reflective metal layer, the reflective layer of the micromirrors is protected from environmental circumstances, oxidation, degradation, acid, base, and galvanic corrosion of the micro-mechanical structures. Also the new coating structure enhances the performance of the micromirror array device by reducing degradation of the reflectivity of the metal layer, by providing anti-reflection in the optically non-effective area, and by protecting the micro-mechanical structures.