Micro-Origami and Micromirrors

Researchers in Japan have created tiny hinged micromirrors, fractions of a millimeter across, that lift themselves up into place during fabrication. The key to the micro-origami technique is to manufacture hinges out of a pair of material layers with slightly different atomic spacings. This lattice mismatch causes a stress that in turn bends the hinge and, in this case, raises a mirror above the substrate. The effect is reminiscent of the bimetallic strips in some thermostats, which consist of bonded layers of metals that expand at different rates when heated, leading to stresses that bend the strips as temperatures change.

Potentially, the micro-origami mirror could lead to optical MEMS switches or other small devices that automatically pop into place without human or mechanical intervention, dramatically speeding and simplifying construction of miniature machines.

Reported by: J. M. Z. Ocampo et al., Applied Physics Letters, 3 November 2003

Associated Physics News Update