New considerations for travelling wave particle handling

Different small-scale devices for particle micro-handling using an AC electric field boundary wave were proposed by F.M. Moesner et. al. (1995). These devices, with various novel transportation and manipulation features, that instantly generate particle driving forces through electric field creation, have been designed and produced. In a further endeavour, the mechanisms of particle conveyance are subsequently validated in experiments. Particles on a thin protecting and insulating film interface above a series of encased and insulated parallel field electrodes become either tribo-electrically or induction charged through the application of balanced three- or six-phase voltages. The created nonuniform travelling field-wave conveys the charged particles perpendicular to the electrodes by repulsive forces in a hopping mode from electrode to electrode. In a temperature and humidity controlled environment, experiments surveying particle conveyance dynamics on these electric devices have been carried out with help of a high speed camera. The applied experimental voltages included triangular, ramp and two customized profiles. Various particle materials with diameters up to 400 /spl mu/m have been examined; metal, glass, and plastic spheres showed the best performances. The transient charge distribution on particles and on the activated electric device, which is responsible for the particle conveyance, has been inspected by a modified scanning electron microscope (SEM). Further, theoretical considerations underline the experimental findings.