Non-contact micromanipulation system with computer vision

Abstract

Laser trapping, which was first demonstrated in 1970 by Ashkin and is well-known as optical tweezers, is a powerful micro- or nano-manipulation tool suitable for a closed working space such as a Lab-on-a-Chip, since it enables the manipulation of micron-sized objects without physical contact, in contrast to a mechanical micro-manipulator using a glass capillary. However, the control and vision systems of a conventional laser trapping system are insufficient to manipulate the objects in 3-dimensional space, if the intention is to dexterously or automatically manipulate the objects in real-time. We have developed an optical tweezers system with an excellent user-interface and real-time image processing functions. In the present paper, a concept of automated noncontact micromanipulation based on visual information and fields suitable for its application are proposed, and the system configuration of the developed system is described. The results of several demonstrations, namely the automated arrangement of micro-beads and micron-sized non-spherical objects, are also described. In our automated manipulation experiment, the micro-beads dispersed in water are detected by a real-time image processing technique, and then trapped and transported to be arranged in desired patterns. In the other experiments, whiskers and diatoms of non-spherical shape suspended in water are automatically detected and stably trapped by the simultaneous irradiation with multiple trapping beams. © 2009 Springer Berlin Heidelberg.