文档介绍：Lecture 6 Designs of MEMS /NEMS 1
清華大學材料科學與工程系
廖建能教授
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NTHU, Chien-Neng Liao
MEMS/NEMS Design
Ideas
Functionality, applications, problems/limitations,…
Micro/Nano-scale operation principles
Physical, chemical and biological models,
material properties, scaling effect,…
Analysis and modeling of devices and systems
Packaging and integration
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NTHU, Chien-Neng Liao
Energy Transformation
Thermal
Mechanical
Electrical
Thermoelectric, Joule heating, thermal resistive,…
Piezoelectric, piezoresistive,…
Thermal expansion, T-dependent phase transformation, …
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NTHU, Chien-Neng Liao
Thermal Actuators
Thermal energy transformed into mechanical movement
Once applying a current, the narrow beam will be heated up more and expand more due to higher resistance and current density.
Once stopping current input, the structure e back to original position
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NTHU, Chien-Neng Liao
Thermal Actuators
Thermally driven cantilever beam
Thermal expansion mismatch induced actuation
Thermal resistive heating (poly wire) to change the temperature of the beam
Electrical → Thermal → Mechanical
pit
pad
Poly wire
beam
Metal 1
A
A’
beam
Poly wire
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NTHU, Chien-Neng Liao
Shape Memory Alloys
Medical
- Microsurgical instruments, stents, artificial muscle
Aerospace
- Connectors, lock rings
Automotive
- Ni-Ti thermostat
Industrial
- Valves, pipe connectors
Consumer
- Eyeglass frames
Safety
- Fire safety valves
SMA valve open and release hot water at the proper temperature
NiTi surgical tools: Precise bending of the tool to the proper shape in micro-surgery
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NTHU, Chien-Neng Liao
Piezoelectric Actuator
Piezo. Mat.
Piezo. Mat.
Piezoelectric stack actuator
Piezoelectric bimorph actuator
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NTHU, Chien-Neng Liao
Inchworm stepping motors
Movement along a rod by 3 piezoelements
“Unlimited” movement
Good resolution
Maximum speed 2 mm/s
Drawbacks
- Expensive
- Small lateral load
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NTHU, Chien-Neng Liao
Piezoresistive AFM
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NTHU, Chien-Neng Liao
ic A