Continuous-membrane surface-micromachined silicon deformable mirror

Abstract

The authors describe the development of a new type of micromachined device designed for use in correcting optical aberrations. A nine-element continuous deformable mirror was fabricated using surface micromachining. The electromechanical behavior of the deformable mirror was measured. A finite-difference model for predicting the mirror deflections was developed. In addition, novel fabrication techniques were developed to permit the production of nearly planar mirror surfaces.

Static and dynamic micro deformable mirror characterization by phase-shifting and time-averaged interferometry

“…A very thin 15mm-diameter reflective membrane is suspended above an array of 37 electrodes, patterned on a PCB [1]. With surface micromachining technology, Boston Micromachines has built in 2000 a 3*3mm² deformable mirror, with 140 actuators with 1μm actuator stroke and a 1.5μm maximal deformation of the membrane [2]. These mirrors show good capabilities but their characteristics cannot complete the next generation WFC requirements.…”

A 45-element continuous facesheet surface micromachined deformable mirror for optical aberration correction

“…Assuming that the displacements of the driving element and the adjacent element are x and y, respectively, these three forces then can be expressed as follows: 19,20 …”

Design of Adaptive Optics Based Systems by Using MEMS Deformable Mirror Models

“…A unique characteristic of the Boston Micromachines deformable mirror technology is the inclusion of a third layer in the design as shown in Figure 1b. This third layer is a thin silicon beam that is doubly cantilevered at both ends, attached to the deformable mirror's continuous facesheet by a thin post, and suspended over an electrostatic actuator pad located underneath the actuator beam's bottom surface (Bifano et al 1997). By charging the pad below, an attractive electrostatic force pulls down on the actuator beam and attached facesheet surface.…”

“…In a typical MEMS deformable mirror, a membrane (Dayton et al 2002) is suspended over a pattern of electrostatic actuators, with the possibility of additional microstructures (Bifano et al 1997) to affect the membrane movement. Because the electrostatic actuators in the MEMS deformable mirrors can only pull on the membrane surface, and because the shape of the membrane itself is determined by the associated membrane mechanics, there are tradeoffs in the achievable amplitude of wavefront correction with respect to spatial frequency, temporal frequency response, and amplitude.…”