Page 269 - Microsensors, MEMS and Smart Devices - Gardner Varadhan and Awadelkarim
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Therefore, we describe in detail here four of the most important types of mechanical
microsensors, namely,
• Pressure microsensors (Section 8.4.5)
• Microaccelerometers (Section 8.4.6)
• Microgyroscopes (Section 8.4.7)
• Flow microsensors (Section 8.4.8)
8.4.2 Micromechanical Components and Statics
There are a number of micromechanical structures that are particularly important because
they are used as the basic building blocks for a whole host of different microsensors (and
for microactuators and MEMS). In their simplest form, these micromechanical structures
are simply
• A cantilever beam
• A bridge
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• A diaphragm or a membrane
Figure 8.20 shows a schematic diagram of each of these three types of microstructures
in both plane view and in cross section. The physical dimensions of the structures are
defined in the figures, such as length l, width w, thickness d, and breadth b. In this
example, the bridge is shown on the top of the supporting structure, which as we shall
see subsequently, is a common feature of microbridges.
Top view
Cross section
Figure 8.20 Basic microstructures: (a) cantilever beam; (b) bridge; and (c) diaphragm or
membrane
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A membrane is formed by tension and a diaphragm is formed by stiffness; therefore, if a structure exhibits
elasticity, it is a diaphragm.
