Double-Layered Vibratory Grating Scanners for High-Speed High-Resolution Laser Scanning

A novel micromachined electrostatic double-layered vibratory grating scanner has been successfully developed for high-speed high-resolution laser scanning applications. This paper presents its design, modeling, fabrication, and measurement results. A comprehensive dynamic model considering the geometric nonlinearity of the platform suspension flexures is also proposed to predict the dynamic performance of the device at large scanning amplitudes. Compared with previously reported single-layered vibratory grating scanners, double-layered scanners - in which the diffraction grating and its driving actuator are located in different layers - have the potential to scan at large amplitudes and at high scanning speeds with large aperture sizes. We have demonstrated a prototype with a 2-mm-diameter diffraction grating which is capable of scanning at 23.391 kHz with an optical scan angle of around 33° and a resulting θ_opticalD product (product of the optical scan angle and diameter of the diffraction grating) of 66 deg mm.