Characterization of an open-loop controlled scanning stage using a knife edge optical technique

Our experimental confocal microscope project required the construction of a high performance scanning stage. In order to understand the scanning stage behavior we modeled each axis of motion as a damped harmonic oscillator, a nd measured its mechanical response using an optical knife edge technique. In order to maximize the scan stage accuracy and performance we used the ch aracterization results of the stage to implement first order correction for such influences as the mass, the damping, and the stiffness of the springs of the scanning stage. We show that the stage can be driven over a range o f frequencies and motion wave forms, without inducing primary resonant resp onse, and this results in an improved quality of the confocal images. We ha ve constructed a novel scanning motion incorporating the corrected results. The linearity of motion was found to be better than with a ramp or sine wa ve driving voltage, enabling an order of magnitude increase in speed of acq uisition. (C) 2000 American Institute of Physics. [S0034-6748(00)00901-1].