Aimed to build a dual-axes confocal endomicroscope with an outer diameter of 5.5mm for in-vivo imaging applications, an electrostatic MEMS scanner has been developed to enable two dimensional (2D) light scanning in either horizontal plane or vertical cross-sectional plane. The device has a compact structure design to match the dual axes confocal architecture in the probe without blocking the collimated light beams of excitation and collection, and a cutting-free silicon-on-insulator(SOI) micromachining process is used for the fabrication. A novel lever-based gimbal-like mechanism is employed to enable three degrees of freedom motions for lateral and axial light scanning, and its geometry is optimized for achieving large deflection with high scanning speed. Based on parametric excitation, the device can work in resonant modes. Testing result shows that, up to ±27° optical deflection angle for inner axis torsion motion with a frequency of ~4.9kHz, up to ±28.5° optical deflection angle for outer axis torsion motion with a frequency of~0.65kHz and ~360μm stroke for out-of-plane translation motion with a frequency of ~0.53kHz are achieved with <60V driving voltage. Based on these results, 2D imaging with frame rate of 5~10Hz and large field of view (1000μm x 1000μm in horizontal plane and 1000μm x 400μm in vertical plane) can be enabled by this scanner.
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