Submicron stereolithography for the production of freely movable mechanisms by using single-photon polymerization

Our group has developed an advanced micro stereolithography system by using single-photon polymerization with an He-Cd laser of 442 nm. This system takes advantage of pinpoint solidification generated at a tightly focused spot inside a liquid photopolymer. This three-dimensional (3D) pinpoint exposure technique allows true 3D microstructures to be fabricated without relying on layer-by-layer processing unlike conventional micro and macro stereolithography. The resolution has also been improved to 0.43 mum, which is close to the diffraction limit of light, without any nonlinear optical process such as two-photon absorption. Moreover, the direct drawing technique inside the liquid photopolymer makes it possible to fabricate freely movable micromechanisms without support parts or sacrificial layers. Using this process, we successfully fabricated several movable microstructures such as micro rotators and micro gears. (C) 2002 Elsevier Science B.V. All rights reserved.