A Into-Plane Rotating Micromirror Actuated by a Hybrid Electrostatic Driving Structure

A novel into-plane rotating micromirror actuated by a hybrid electrostatic driving structure is presented.The hybrid driving structure is made up of a planar plate drive and a vertical comb drive.The device is fabricated in SOI substrate by using a bulk-and-surface mixed silicon micromachining process.As demonstrated by experiment,the novel driving structure can actuate the mirror to achieve large-range continuous rotation as well as spontaneous 90. rotation induced by the pull-in effect.The continuous rotating range of the micromirror is increased to about 46 degree at an increased yielding voltage.The measured yielding voltages of the mirrors with torsional springs of 1 and 0.5μm in thickness are 390～410V and 140～160V,respectively.The optical insertion loss has also been measured to be -1.98dB when the mirror serves as an optical switch.