Overview . MEMS: MicroElectroMechanical System.Scales of MEMS: 1 micro meter to 1 millimeter (10-6 to 10-3 m).Two principal components in MEMS: a sensing or actuating element and a singal transduction unit.. Purpose of Microsensors. To sense the existence or the intensity of certain physical, chem
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1. MEMS and Microsystem Chapter 1
2. Overview MEMS: MicroElectroMechanical System.
Scales of MEMS: 1 micro meter to 1 millimeter (10-6 to 10-3 m).
Two principal components in MEMS: a sensing or actuating element and a singal transduction unit.
3. Purpose of Microsensors To sense the existence or the intensity of certain physical, chemical, or biological quantities.
Physical quantities: pressure, temperature, force, magnetic flux.
Chemical quantities: chemicals or toxic gases like CO, CO2, NO, O3.
4. Advantages of Microsensors Sensitive and accurate with minimal amount of sample substances.
No interference to the main field.
Can be mass produced in large volumes.
Disposable, no cleaning or maintaining efforts required.
5. An Example of Microactuator Use charged parallel conducting plates.
Charged plates result in electrostatic force that prompt relative motion.
A microgripper is a popular example.
6. A Micro System A micro-system contains MEMS components.
It includes three major components of micro sensors, actuators and a processing unit.
Airbag deployment system is a micro system.
Impact of car felt by sensor
Sensor signal processed by the processor
Processor sends a signal to actuator to deploy airbag.
7. An Intelligent Micro System
8. Typical MEMS Products Micro gears.
A gear smaller than an ant’s head.
The diameter of the central gear is 0.7mm.
The diameter of the rotor gear is 0.13mm.
The maximum speed is 150,000 rpm.
9. Micro-fabrication Micro-fabrication: the technologies to produce MEMS components.
Traditional machining cannot used to produce MEMS components.
Micro-structure can be produced by chemical etching process.
Thin-film deposition techniques used to build layers on based materials.
10. Micro-electronic and MEMS MEMS fabrication technology was developed based on micro-electronic techniques.
However, there are differences between them.
MEMS involves more materials than ME.
MEMS has moving parts.
ME: 2D structure; MEMS: 3D structure.
ME: completely protected from packaging; MEMS: sensors is interfaced with outside environment.
11. Disciplines involved in MEMS
12. Science Disciplines for MEMS Sciences disciplines: electrochemical (sensors), electro-hydrodynamics (mechanical movement), molecular biology (sensors, manufacture), plasma physics (micro-fabrication), scaling law (design), quantum physics (modelling for micro-scale), molecular physics (modelling for materials in micro scale).
13. Engineering disciplines for MEMS Mechanical engineering (design of micro-structure), electrical engineering (power supply, functional control and signal processing), chemical engineering (micro-fabrication), material engineering (selecting materials for micro-fabrication) and industrial engineering (production and assembly of MEMS).
14. MEMS and Miniaturization The advantages of miniaturization:
Smaller system moves more quickly.
Smaller devices suffer less in thermal distortion and vibration.
Suitable for application in medicine and surgery.
Suitable for space industry.
Suitable for telecommunication systems.
Miniaturization – to perform multifunction with manageable size.
15. Example of Miniaturization The first general purpose computer in 1946, measured 80ft long by 8.5ft high and several ft wide.
18,000 vacuum tubes.
A single chip 50 years later to do the same job.
A reduction of volume more than 6 orders.
16. An Example of Micromachine Weigh 33 mg.
Size: 4.785mm long by 1.730 mm wide by 1.736 mm high.
With electrical motor of 0.6mm in diameter.
17. Micro-systems in Automobiles At the present, two major markets for MEMS are computer storage systems and automobiles.
Automobiles use a lot of micro-sensors and micro-actuators.
MEMS help achieve safety, comfort for car passenger and high fuel efficiency and low emissions.
Sensors are extensively used in car engines.
A pressure sensor in engine manifold.
18. MEMS Future Use in Cars In 2005, there are excepted 65 millions cars being produced.
Future cars need to be smarter to meet customers’ demands.
Smarter cars means use more MEMS or micro-systems.
19. MEMS in other Industries MEMS also used in health care, aerospace, industrial products, consumer products and telecommunication.
Market for MEMS is expected to rise in the future.
20. A Microsensor Assembly
21. Micro-actuator Assembly
23. A Micro System
24. A Micro Inertia Sensor
25. A Micro-gear
26. A Micro Motor
27. A Micro Turbine
28. Computer in 1946
29. A Single Chip in 1996
30. Sensors Used in A Car Engine
31. A Pressure Sensor
32. Growth of MEMS Market