2. TOPICS INCLUDED IN THIS
PRESENTATION
INTRODUCTION
OPTICAL
SENSORS
PRINCIPLE OF SENSORS
CLASSIFICATION AND COMPARISON
SOME INTERESTING APPLICATIONS
CHRONOLOGY
CONCLUSION
2
3. SENSOR INTRODUCTION
A sensor is a device that produces a measurable
response to a change in a physical condition,
such as temperature or thermal conductivity, or
to a change in chemical concentration. Sensors
are particularly useful for making in-situ
measurements such as in industrial process
control.
Sensors are responsible for converting some
type of physical phenomenon into a quantity
measurable by a data acquisition (DAQ) system.
3
4. OPTICAL SENSOR
INTRODUCTION
NEW
REVOLUTION OF OPTICAL
FIBER SENSORS
IT IS A “SPIN-OFF” FROM OTHER
OPTICAL TECHNOLOGIES
SEEING THE POTENTIAL IN
SENSING APPLICATIONS –
DEVELOPED AS ITS OWN FIELD
4
9. INTRINSIC SENSORS
INTRINSIC SENSORS ARE DIFFERENT IN THAT THE
LIGHT BEAM DOES NOT LEAVE THE OPTICAL FIBER
BUT IS CHANGED WHILST STILL CONTAINED WITHIN IT.
9
10. COMPARISON OF THE TWO TYPES
EXTRINSIC
INTRINSIC
APPLICATIONS-
APPLICATIONS-
TEMPERATURE,
PRESSURE,LIQUID
LEVEL AND FLOW.
ROTATION,
ACCELERATION, STRAIN,
ACOUSTIC PRESSURE
AND VIBRATION.
MORE SENSITIVE
TOUGHER TO
MULTIPLEX
REDUCES CONNECTION
PROBLEMS
MORE ELABORATE
SIGNAL DEMODULATION
MORE EXPENSIVE
LESS
SENSITIVE
EASILY MULTIPLEXED
INGRESS/ EGRESS
CONNECTION
PROBLEMS
EASIER TO USE
LESS EXPENSIVE
10
11. Types of Optical Sensors
Chemical/Gas Concentration
Temperature
Strain
Biomedical
Electric & Magnetic Fields
Rotation
Pressure
Displacement &Position
11
13. Chemical/Gas Sensor Types and
Applications.
Sensor
type
Detectable
gases
Usable
range
Pro's
Con's
ppm levels
3 year lifetime
slightly lower at
Low power, accurate,
high temps; some
repeatable
types are crosssensitive
Flammables
LEL levels
Can be damaged by
Generally good in all high levels of H2S,
ways; portable
but poison resistant
types are available
Infrared
Flammables and CO2
0.1 (or less) to
100% by volume
Fail safe; generally
excellent
Thermal
Conductivity
Many, at % levels,
including binary
mixtures
% levels
20 year life (at least);
Only appropriate for
stable; can detect
certain gases
inert gases
Electrochemical
Pellistor
Toxics, oxygen
Expensive (but
getting cheaper);
non-portable
13
15. TYPES OF TEMPERATURE
SENSORS
Thermocouples
Thermistors
Radiation
Pyrometer
Radiation Thermometers
Resistance Temperature Detectors
Fiber Optic Temperature Sensors
Silicon Temperature Sensors
15
16. APPLICATIONS
HVAC - room, duct, and refrigerant
equipment
Motors - overload protection
Electronic circuits - semiconductor protection
Electronic assemblies - thermal management,
temperature compensation
Process control - temperature regulation
Automotive - air and oil temperature
Appliances - heating and cooling temperature
16
17. STRAIN SENSORS
FIBER
BRAGG GRATINGS (FBG)
TECHNOLOGY
SENSES AS LITTLE AS 9
MICROSTRAIN
NRL and UNITED TECHNOLOGY
RESEARCH
17
19. ELECTRICAL AND MAGNETIC
SENSORS
APPEALING-
INHERENT DIELECTRIC
NATURE
LESS SENSITIVE TO
ELECTROMAGNETIC INTERFERENCE
SMALL SIZE AND SAFER
THEY ARE ALMOST ALWAYS HYBRID
ABB CORPORATION RESEARCH
CENTER
19
20. APPLICATION
Compassing
and navigation
Vehicle Detection
Virtual Reality
Laboratory Instrumentation
a Medical Instruments
Underground Boring Equipment
Flux Gate Replacement
20
21. ROTATION SENSOR
BASED
ON THE SAGNAC EFFECT
TWO TYPES RING LASER
GYROSCOPE (RLG) AND FIBER
OPTIC GYROSCOPE (FOG)
US COMPANIES PURSUING HIGH
PERFORMANCE FOG’s
(HONEYWELL, LITTON, NORTHRUP,
ALLIED SIGNAL etc.)
21
22. PRESSURE SENSORS
EARLIER
BASED ON
PIEZORESISTIVE TECHNIQUE
BASED ON MOVABLE DIAPHRAGM
HIGH PERFORMANCE(POLARIZATION BASED SENSORS)
OPERATING PRESSURE RANGES
FROM 0-70,000 torr
22
23. DISPLACEMENT AND
POSITION SENSORS
ONE
OF THE FIRST
OPTOELECTRONIC SENSORS TO BE
DEVELOPED.
SIMPLE SENSORS RELY ON THE
CHANGE IN RETROREFLECTANCE
DUE TO A PROXIMAL MIRROR
SURFACE
ALSO REFERRED AS LIQUID LEVEL
SENSORS
23
24. WHY OPTICAL SENSORS
ELECTROMAGNETIC
IMMUNITY
ELECTRICAL ISOLATION
COMPACT AND LIGHT
BOTH POINT AND DISTRIBUTED
CONFIGURATION
WIDE DYNAMIC RANGE
AMENABLE TO MULTIPLEXING
24
25. APPLICATIONS
MILITARY AND LAW ENFORCEMENT
THIS SENSOR ENABLES LOW LIGHT IMAGING AT TV FRAME
RATES AND ABOVE WITHOUT THE LIMITATIONS OF VACUM TUBE
BASED SYSTEMS.
25
26. NIGHT VISION CAMERA (contd.)
COMPRISES OF :
AMPLIFIED CCD SENSOR
ANTI BLOOMING TECHNOLOGY
CRYSTAL POLYMER SHUTTER
ADVANTAGES :
EXCEPTIONAL DAY LIGHT RESOLN.
IMMUNE TO OVER EXPOSURE
VERY HIGH CONTARAST LEVELS
NO HALOING OR SCINTILLATIONS
26
27. BIOMETRICS
YOUR FACE, FINGERS AND EYES IN A WHOLE
NEW LIGHT
• IMAGE CAPTURE
• IMAGE PROCESSING
• FEATURE EXTRACTION
• FEATURE COMPARISON
27
28. PARTIAL DISCHARGE DETECTION
USES OPTICAL FIBER SENSORS
OPTICAL FIBER SENSORS ARE BEING TESTED FOR USE
IN DETECTING PARTIAL DISCHARGES IN ELECTRICAL
TRANSFORMERS. PINPOINTING SUCH DISCHARGES IS
ESSENTIAL TO PREVENTING INSULATION BREAKDOWN
AND CATASTROPHIC FAILURES.
28
29. CONCLUSIONS
LOOKING AT THE INDUSTRY
TRENDS IN THE PAST 2 DECADES
AND THE EXPONENTIAL CURVE IT
SEEMS TO ME THAT THERE IS
GOING TO BE A LOT OF RESEARCH
AND IMPROVEMENTS TO THE
EXISTING SENSORS
OPTICAL SENSORS ARE HERE TO
STAY !!!!
29
30. THANK YOU FOR YOUR
PATIENCE AND TIME
QUESTIONS ??
30
