Actuator for Out-Of-Plane MEMS Devices

The proposed research program is an innovative solution to a critical problem: maintaining stable distance between front and back covers in large, evacuated flat electronic visual displays. Evacuation is necessary because atmospheric pressure distorts the front and back plane surfaces. A solution consists of placing many small columns between the surfaces to hold them apart at a precise distance. Spacers can be etched from a thick layer deposited on the surface, but this process requires high aspect ratio lithography and may leave residue which outgasses. We propose to micromachine columns and actuators in or near the surface plane of a substrate, such that when the actuators operate they rotate the columns perpendicular to the surface. Phase I is intended as a proof-of-concept: miniature blocks (microns thick, tens of microns wide, and hundreds of microns long) will be micromachined in the surface of a wafer, and released by etching a sacrificial layer. Shape-memory thin-film micro-actuators will rotate the blocks into standing position. In Phase II an array of electron emitters will be combined with this technology to test a complete field-emission flat-panel display.