In "Micromachines made easy," PhysicsWeb tells us that "scientists in Sweden have developed a novel technique for making micromachines and demonstrated its potential by making a micro pinball table."
Martin Bring and colleagues at the Chalmers University of Technology and the Institute of Microelectronics in Gothenburg believe that their process overcomes many of the problems associated with the 'dry etching' step that is conventionally used to fabricate silicon-based microelectromechanical (MEMS) devices.
Here are some details about how they developed this pinball table.
Bring and colleagues built a micro pinball table in which silicon cantilevers acted as the 'flippers', magnetic beads 150 microns in diameter were the balls, and the table measured 25 millimetres square. They started with two 700-micron thick wafers of single crystal silicon and used a combination of oxidation, patterning and dry etching to make the device
Here is an illustration of the MEMS pinball game (image credit: M Bring et al).
The researchers put in the balls 'by hand' and tilted the table at an angle of 20 degrees to the horizontal (figure 2). They found that the speed of a ball could reach up to 0.75 kilometres per hour -- or 210 000 microns per second. This is equivalent to a football having an almost supersonic speed of 1125 km per hour.
Fascinating, but is it useful? Accoording to the scientists, this technology "could provide an easy and robust alternative to existing methods." And this process could be used to build devices as diverse as "transducers in sensors, micromirros in digital projectors, and optical switches."
If you're interested, you can download pinball movies at this MEMS-Pinball page.
Source: Belle Dumé, PhysicsWeb, June 18, 2003
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