An Introduction to mems (Micro-electromechanical Systems)
tải về 1.48 Mb. Chế độ xem pdf
|
| An Introduction to MEMS
Prime Faraday Technology Watch – January 2002 12
Future lab-on-a-chip technology may include implantable ‘pharmacy-on-a-chip’ devices to carefully release drugs into the body from tiny chambers embedded in a MEMS device, eliminating the need for needles or injections. The delivery of insulin is one such application, as is the delivery of hormones, chemotherapy drugs and painkillers. First generation devices are being developed which release their medication upon signals from an outside source, wired through the skin. Proposed second generation devices may be wireless and third generation MEMS chips could interact with MEMS sensors embedded in the body to respond to the body’s own internal signals.
One of the most recent MEMS microfluidic devices to emerge from development laboratories incorporates a ‘Pac-Man’-like microstructure that interacts with red blood cells (Figure 11b). The device from Sandia National Laboratories, U.S.A, contains silicon microteeth that open and close like jaws trapping and releasing a single red blood cell unharmed as it is pumped through a 20 µm channel. The ultimate goal of this device is to puncture cells and inject them with DNA, proteins, or pharmaceuticals to counter biological or chemical attacks, gene imbalances and natural bacterial or viral infections.
ii) MOEMS Optical communications has emerged as the only practical means to address the network scaling issues created by the tremendous growth in data traffic caused by the rapid rise of the Internet. Current routing technology slows the information (or bit) flow by transforming optical signals into electronic information and then back into light before redirecting it. All optical networks offer far superior throughput capabilities and performance over traditional electronic systems.
The most significant MOEMS device products include waveguides, optical switches, cross connects, multiplexers, filters, modulators, detectors, attenuators and equalizers. Their small size, low cost, low power consumption, mechanical durability, high accuracy, high switching density and low cost batch processing of these MEMS-based devices make them a perfect solution to the problems of the control and switching of optical signals in telephone networks. An example of a MEMS optical connect is shown in Figure 12. Here a network of 256 MEMS micromirrors route information in the form of photons (the elementary particle that corresponds to an electromagnetic wave) to and from any of 256 input/output optical fibres.
Figure 11. (a) Micromachined microtitreplate with 96 cavities filled by capillary force [18,19], and (b) a bioMEMS device actuated with ‘microteeth’ to trap, hold and release single red blood cells (unharmed). The little balls in the channels are red blood cells [2]. |