An electrostatic vertical microscanner for phase modulating array-type Mirau microinterferometry

We present a micromachined vertical scanner with a array of suspended 'spider-type' micromirrors which is a key component of a multi-channel 'active' Mirau microinterferometer. The microscanner provides for the vertical displacement of the reference micromirrors for the implementation of the phase shifting technique. Vertical comb-drive structures are employed for actuation of the micromirrors (displacement range of hundreds of nm at 500 Hz) as well as for in situ capacitive displacement sensing. Integration of micro-opto-electro-mechanical microscanners in a handheld interference microscope has the advantage of significantly decreasing instrument size because of the small footprint of the microscanner. Particularly interesting applications of the microscanner are low-cost and portable microsystems for the parallel inspection of biological tissues, e.g. for early diagnosis of specific diseases such as skin cancers.