A MEMS Electrostatic Roll-Up Window Shade Array for House Energy Management System

We report on an electrostatically reconfigurable roll-up microshutter array by using the mechanical unimorph effect of laminated metal-SiO2 microcantilevers. The shutter array is designed as a tunable shade to control the incoming sunlight through windows. Materials and fabrication are chosen to be in compatible with the thin-film-transistor technology for electrically addressing. The shutter is 200-mu m long, 30-mu m wide, and 0.3-mu m thick. The radius of the shutter curvature is 70 mu m, which is quantitatively predictable by Timoshenko's model for the unimorph structure. The shutter is electrostatically closed at 55 V and released at 38 V to, respectively, switch the mechanical aperture between 0% and 55%. Optical transmittance is controlled between 36% (close) and 53% (open).