Micro-mirrors and other hinged microstructures have numerous MEMS applications. Such micro-mirrors can be used in laser-interferometry, laser beam modulation, fiber-optical switching, laser scanners and printers and a variety of other optical applications.
A pop-up mirror device is proposed which consist of a hinged polysilicon mirror mounted on a silicon substrate. The folding mirror, with one fixed hinge and two floating hinges, is designed such that the mirror is lifted off the substrate by the linear movement of a shaft from an actuating system. The assembly uses a simple three-layer process such as MUMPS (Multi User MEMS Process). The fixed hinge is constructed in all three structural layers. The mirror lifting arm and the mirror arm are designed in both the second and the third structural layers and the floating hinge, linking them, is formed by cross members of the second and third structural layers.
The motion of the mirror for different mirror lengths was simulated. Based on these predictions the geometry of the mirror was determined and then the components were simulated for various mechanical loads. The initial simulations of the device involved analyzing the stresses and displacements of the mirror and the mirror lift arm. The stress on the components was found to be acceptable for preliminary fabrication prototyping.