A surface-micromachined vertical scanning micromirror

A vertically supported, two-axial scanning micromirror with an optical reflection area of 600 μm × 600 μm has been successfully demonstrated using a 2 μm thick standard planar polysilicon surface micromachining process. The micromirror was lifted from the substrate and vertically supported by locking springs and hinges using a micromanipulator under a probe station. It was torsionally actuated in the two orthogonal angular directions including the first that is normal to the substrate and the second that is normal to the plane of the vertically supported microstructure. Furthermore, under an ac driving voltage of 2.5 V and dc bias voltage of 5 V, it was able to reflect and generate laser light patterns on a distant screen. The scanned and reflected laser light was able to make a circular pattern at f = 387 Hz, an elliptical pattern at f = 350 Hz and a line pattern at f = 427 Hz. As such, this surface-micromachined vertical mirror system could have potential applications for an optical bench on a chip. (Some figures in this article are in colour only in the electronic version)