Long-term stresses on linear micromirrors for pico projector application

Micro electromechanical system (MEMS) micromirrors are interesting devices to be adopted in pico projector application. In fact, together with laser sources, they can be adopted to obtain an always in focus projected image. The reliability of these devices is not yet been addressed. In this paper, we investigate the reliability of micromirrors subjected to long-term stresses. The preliminary results and their interpretation is addressed at the end of this paper. The results led us to think about two different degradation mechanisms. Permanent and recoverable stiffness variation can both influence the mechanical tilting angle of the device during long-term stresses. These two different mechanisms may affect the correct behavior of the device. Further measurements will be needed in order to validate the preliminary hypothesis made in the last section of this paper.