31-07-2012, 11:54 AM
MEMS
A MEMS.pdf (Size: 8.54 MB / Downloads: 321)
Micro Electrical Mechanical Systems
Practice of making and combining
miniaturized mechanical and electrical
components
“Micromachines” in Japan
“Microsystems Technology” in Europe
MEMS Fabrication
Electronics industry : doubles the transistors in
a microchip every 18 months
Using similar techniques : able to manufacture
beams, diaphragm, motors, pumps etc on micro
scale
Microfabrication methods
Bulk Silicon Micromachining
Surface Micromachining
LIGA for Deep Structures
Interesting Facts
0.1mgrams Proof Mass
0.1pF per side for the Differential Capacitor
20aF (10-18f) least detectable Capacitance change
Total Capacitance change for Full Scale is 10fF
1.3mm gaps between Capacitor Plates
0.2A minimum detectable beam deflection
1.6mm between suspended beam and substrate
10 to 22 kHz resonant frequency of beam
Advantages
Low cost (can even be made “disposable”)
FFTs can be used to increase the
performance
Will work for many machine health
applications
Onboard signal conditioning. No charge
amplifiers required.
Disadvantages
Performance still below that of more
expensive sensors
May not be available in industrial
hardened packages
Summary
New accelerometers open the door for new
applications in tilt, inertial and vibration
¾ Low cost
¾ High level of integration: Multiple sensors, signal
conditioning
Clever design can allow use of a less accurate but
less expensive sensor
¾ using microcontrollers for calibration and algorithms
¾ Using signal analysis to improve noise levels
¾ Taking new approaches to traditional problems
A MEMS.pdf (Size: 8.54 MB / Downloads: 321)
Micro Electrical Mechanical Systems
Practice of making and combining
miniaturized mechanical and electrical
components
“Micromachines” in Japan
“Microsystems Technology” in Europe
MEMS Fabrication
Electronics industry : doubles the transistors in
a microchip every 18 months
Using similar techniques : able to manufacture
beams, diaphragm, motors, pumps etc on micro
scale
Microfabrication methods
Bulk Silicon Micromachining
Surface Micromachining
LIGA for Deep Structures
Interesting Facts
0.1mgrams Proof Mass
0.1pF per side for the Differential Capacitor
20aF (10-18f) least detectable Capacitance change
Total Capacitance change for Full Scale is 10fF
1.3mm gaps between Capacitor Plates
0.2A minimum detectable beam deflection
1.6mm between suspended beam and substrate
10 to 22 kHz resonant frequency of beam
Advantages
Low cost (can even be made “disposable”)
FFTs can be used to increase the
performance
Will work for many machine health
applications
Onboard signal conditioning. No charge
amplifiers required.
Disadvantages
Performance still below that of more
expensive sensors
May not be available in industrial
hardened packages
Summary
New accelerometers open the door for new
applications in tilt, inertial and vibration
¾ Low cost
¾ High level of integration: Multiple sensors, signal
conditioning
Clever design can allow use of a less accurate but
less expensive sensor
¾ using microcontrollers for calibration and algorithms
¾ Using signal analysis to improve noise levels
¾ Taking new approaches to traditional problems