Equipped with a microlens about 300 microns in diameter, the microscopic scanner Lee tested is a square of about 1 millimeter on each side and can move a distance of 50 to 100 microns. Lee is also testing a nanolens as small as 500 nanometers in diameter, or 200 times thinner than a strand of human hair, and smaller than the average red blood cell.
Lee's design of the micro-CIA will include three scanners stacked vertically above the staging platform where samples are studied. The scanners will measure each of the three axes - X, Y and Z - in three-dimensional space.
To make the scanner and lens, Lee employed technology similar to that used to manufacture microchips. The lens is made of a tiny drop of polymer shaped by surface tension and hardened by exposure to ultraviolet light. To focus the lens, Lee and Kwon adjusted the distance between the lens and sample. While it is also possible to focus by changing the shape of the lens, Lee said doing so would likely increase the cost and complexity of production, something he wants to avoid.
Comb-drives on each side of the microlens act as microactuators, tiny engines powered by electrostatic forces that move the microlens back and forth 4,500 times per second. Sensors then pick up fluorescent signals and feed the data back to a computer where the image is displayed in real time.
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Contact: Sarah Yang
scy@pa.urel.berkeley.edu
510-643-7741
University of California - Berkeley
13-Mar-2002