This paper reports a piezoelectric in-plane resonant actuator for a speckle dissolution device used in a laser-type projector. An optical diffuser is oscillated by this actuator to reduce the coherency of a scanned laser beam. A PZT unimorph actuator combined with a Moonie type displacement amplifier and a resonant structure was used to obtain a large displacement. The L18 design of experiment method was used for the optimal design. Both 1-axis and 2-axis actuators were designed and fabricated. The maximμm displacement as high as 239.5 μm at a resonance frequency of 325.2 Hz was obtained for the 1-axis actuator, and the maximμm displacements of 109.5 μm and 67 μm for both x- and y- direction at resonance frequencies of 621.5 Hz and 288.5 Hz were obtained for the 2-axis actuator (10V). The actuator was also tested with a dummy optical diffuser to evaluate the influence of the additional mass.
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