Development of winged microscanners: architecture and performance

Two-dimensional scanners have a variety of applications in displays, barcode readers, optical data storage devices, and free-space optical interconnects. In this paper, the modeling, simulation, fabrication, and testing of a MEMS-based winged microscanner are described. The microscanner is controlled using electrostatic force distributed across multiple electrodes. Compared to previous cantilever designs, the symmetric spring on the beam is adapted to reduce the spring constant of the suspension beam and increase flexibility. In addition, wings are added to further reduce the actuation voltage. A thorough finite element analysis (both static and dynamic) has been completed to study key design parameters such as driving voltage, operating frequencies, and tilt angle. The focus of this work was on the performance analysis of the microscanner, including squeeze film damping effects. Prototype microscanners and four different microscanner arrays were fabricated using the MUMPS process (MEMSCAP). The dynamic performance of the microscanner was then investigated. For a single electrode actuation, the pull-in voltage of the winged microscanner is as low as 4 V, and it is further reduced to 3 V with only two driving electrodes used to actuate the microscanner, which makes it compatible with off-the-shelf control logic circuits. The initial testing results demonstrated that the maximum tilt angle is approximately 2.5°. To increase this tilt angle, a customized process is now being developed.