| 摘要 |
An adaptive alignment technique provides precise control and active positioning in, preferably, two-dimensions of sub-millimeter-sized objects such as, in one application, spherical mircolenses through the application of electrophoretic forces in a microfluidic wells. A lithographically patterned microfluidic well and electrodes can be addressed to position or align a spherical microlens to a corresponding laser light beam. The motion of the microlens is preferably controlled using CMOS compatible voltages (3V-1 muA) that are preferably applied to opposite electrodes in the microfluidic well, creating an electrical field in a well solution. By applying voltages to opposed electrode pairs, movement of spherical microlenses with sizes ranging from, most typically, 0.87 mum to 40 mum in directions parallel to the electrode surface is realized. Under a bias of 3 volts, the microspheres have electrophoretic velocities ranging from 13 to 16 mum/s. Optical alignment of the spherical microlens, as is preferably accomplished by use of feedback from a photo detector, serves to position the microlens for maximum efficiency. Microlenses or other optical elements may thus be aligned to optical fibers, VCSELs, LEDs, photodetectors, etc.
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