Improved micro-optoelectromechanical systems deformable mirror forin vivooptical microscopy

Abstract

Micro-optoelectromechanical systems (MOEMS) deformable mirrors are being developed for focus control in miniature optical systems including endoscopic microscopes and small form-factor camera lenses. A new process is described to create membrane mirrors made from the photoset polymer SU-8. The SU-8 also serves as the adhesive layer for wafer bonding, resulting in a simple, low cost fabrication process. The process details and the optical properties of the resulting focus control mirrors, which have a diameter of 2 mm, a stroke in excess of 8 μm and very low residual aberration, are described. Multiple actuation electrodes allow active control of more than 1.4 μm peak-to-peak of wavefront spherical aberration. The MOEMS mirror is demonstrated in a confocal microscope in which it provides focus control during capture of in vivo images. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

New Endoscopic Imaging Technology Based on MEMS Sensors and Actuators

“…For z -axis focusing (so called axial scanning) capability in microscope, an interesting electro-static MEMS device based on electrostatic working principle has been developed. Dickensheets and colleagues have proposed a unique micromachined deformable SU-8 polymer based membrane mirror for confocal microscope [ 87 , 88 , 89 ]. Agile scanning will be realized by such kind of electrostatic force driven thin-film membranes.…”

Electrostatic-pneumatic membrane mirror with positive or negative variable optical power

“…This method can cause a large deflection of the membrane, but magnetic actuators lead to high power consumption and the speed of focusing is relatively slow. A pneumatic pump may increase the pressure in a sealed cavity beneath a deformable membrane to achieve large deflection although the size of the final L {Ve=O ' T Vp # o device with the bulky pump is not suitable for miniaturized system materials typically cause a small displacement on the membrane so that the focus ra A large deflection on a membrane mirror can be achieved at small voltage using electro speed of focusing is limited to several seconds [22 Recently we described a new actuation concept to use b mirror [23]. In this method electrostatic actuation is combined with pneumatic actuation to achieve either concave or convex surface curvature and to increase the membrane deflection.…”

High speed focus control capability of electrostatic-pneumatic MEMS deformable mirrors

“…MEMS deformable mirrors are versatile elements for optical focus control [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Electrostatic-pneumatic actuation of deformable mirrors offers relatively large membrane stroke to increase the optical focus range [16,17].…”