MEMS: The Functionailty - Part 2

Earlier we had a view of the components of the MEMS #-Link-Snipped-#. Having known this, let us try to study the functional components of the system. This system is broadly classified in 4 parts as stated earlier:

1. Miniaturized structures.
2. Sensors.
3. Actuators
4. Microelectronics.

The miniaturized structures, comprise of the small components like the sensors, actuators etc. of the order of microns. These are sometimes even not visible to the naked eye. This miniaturizing ensures optimum utilization of space and also increases the product efficiency.

Micro sensors can reliably measure parameters like temperature, pressure, magnetic fields, radiations etc. surprisingly the micro-sensors have shown a better performance than their macro counter parts. Now, these micro sensors are the devices that transform the measured quantity into a form acceptable by the next stage components. For example pressure transducer converts the applied pressure into displacement and then it is read by the next stage. A good sensor is:

[*]Sensitive to the measured properties
[*]Insensitive to the external disturbances
[*]It does not influence the measured quantity.

Not only this but the per device production cost is also reduced by the technology.

An actuator is a mechanical device that is used to control a moving or a mechanical system. It can be powered by electric current, pneumatic or hydraulic pressure. Some micro actuators normally used are micro-valves to control the flow of gas, optical switches and mirrors to redirect the light beams, micro-pumps to develop positive fluid pressure, micro-resonators etc. these micro actuators a perform the tasks far bigger than their sizes. For example the micro actuators placed on the edge of the aircraft can steer an aircraft using microelectronics. Now isn’t it great?

The real potential of a MEMS can be harvested when these micro sensors, actuators and structures ca be merged into a common silicon substrate. This assembly is called as microelectronics. The figure below shows an edoscope probe using MEMS.



Applications:



1. Airbag system
2. Brake lights
3. Automatic door locks
4. Headlight leveling in cars
5. Vehicle security system.

This system responds completely like a human being. The sensors sense the physical signals which then direct the actuators to act likewise. It is then analyzed by the microelectronic system, does some decision making and we get a desired output. I think these systems would soon replace every human labor on the shop floor.