An Introduction to mems (Micro-electromechanical Systems)
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| 4. MEMS Transducers
Microsensors and microactuators are at the very core of a MEMS device or system. A microsensor detects changes in the system’s environment; an ‘intelligent’ part processes the information detected by the sensor and makes a decision in the form of a signal; and a microactuator acts on this signal to create some form of changes in the environment. Microelectronic components make up most of the intelligent part of the device and, as an established technology, will not be discussed here.
Sensors and actuators are broadly termed transducers and are essentially devices that convert one form of energy into another. Many of the MEMS sensors and actuators described in this section have been developed within the microelectronics industry and do not all involve any special micromachining techniques; they are based on conventional integrated circuits that, through inherent mechanisms, sense light, temperature etc. However, many of these can be enhanced by the use of MEMS.
Basic MEMS mechanisms and structures consist of both in-plane and out-of-plane mechanisms as well as structural members to couple energy between the actuator and sensors as well as with the physical interface of a mechanical system. Mechanisms such as joints, linkages, gears and hinges are very typical.
This section concentrates on the phenomena that can be sensed or acted upon with MEMS devices with a brief description of the basic sensing and actuation mechanisms. It is important to note that although these devices are mechanical and have been categorized in terms of their sensing domain (e.g. thermal, chemical, radiation), there are many overlaps, and forms of mechanical transducer can be commonly found as intermediate mechanisms in other devices.
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