1. Submitted By:
HITESH KUMAWAT
E.I.C 4th year

2. INTRODUCTION
 Infrared radiations are radiations below (infra) visible
spectrum.
 This emergent dual use technology field is fast
emerging amongst the most technologies used.
 It spans from low-end automatic supermarket door
openers to high-end space based detectors used to
detect nuclear tests, missiles and intra galactic
radiations.

3. HISTORY
 Modern history of IR detectors commenced with
development of first IR detector by Case in 1917.
 discovered that a substance made of thallium and
sulphur exhibited Photoconductivity.
 The 1970's witnessed IR applications combined with
the start of high volume production of first generation
intrinsic MCT sensor systems using linear arrays

4. MEASUREMENT PRINCIPLE

5.  Within this wave band, only frequencies of 0.7 microns to 20
microns are used for practical, everyday temperature
measurement. This is because the IR detectors currently
available to industry are not sensitive enough to detect the
very small amounts of energy available at wavelengths
beyond 20 microns.
 IR energy travels in straight lines from the source and can be
reflected and absorbed by material surfaces in its path.

6. Theoretical Basis for IR
Temperature Measurement
The important formulas are as follows:
 1. Kirchoff's Law: When an object is at thermal
equilibrium, the amount of absorption will equal the
amount of emission.
 2. Stephan Boltzmann Law: The hotter an object
becomes the more infrared energy it emits.
 3. Wien's Displacement Law: The wavelength at which
the maximum amount of energy is emitted becomes
shorter as the temperature increases.

7. IR FUNDAMENTALS
 THERMAL EMISSION:
 Thermal emission emerges from every body above
absolute zero temperature in the form of EM waves
 Atmospheric transmission:
 Atmospheric transmission is a must for all IR
applications on earth

8.  Scene radiation and contrasts:
 Radiation received from any object is the sum of the
emitted, reflected and transmitted radiation.
 Choice of IR band:
 In the spectral range of.0.78 - 3.0 μm, IR detectors are used
for applications as diverse as fiber optic communications,
agricultural sorting, environmental monitoring, and
chemical analysis

9. 1. Thermo resistive sensors
2. Thermoelectric sensors
3. PN junction temperature sensors
4. Optical and acoustic temperature sensors
5. Thermo-mechanical sensors and actuators

10. Thermo resistive sensors
 Two basic types:
 Resistive Temperature Detector (RTD)
 Metal wire
 Thin film
 Silicon based
 Thermistor (Thermal Resistor)
 NTC (Negative Temperature Coefficient)
 PTC (Positive Temperature Coefficient)

11. Thermo resistive effect
 Conductivity depends
on temperature
 Resistance is
measured, all other
parameters must stay
constant. R= L
S

12. Other temperature sensors
 Optical
 Acoustical
 Thermo mechanical sensors
 Thermo mechanical actuators

13. DETECTOR FORMAT AND
ARCHITECTURES
 Hybrid Array
 Z plane hybrid array
 Pseudo monolithic Array
 Monolithic array technology

14. MATERIALS IN IR DETECTOR FORMATS
 Silicon and Germanium detectors
 MCT detectors
 Indium antimonide
 Platinum silicide detectors

15. CONCLUSION
 The IR industry is in transition. After years of existence
as an esoteric technology reserved for military,
academia and narrow niche markets
 Operation at longer wavelengths enables detection of
cold targets at long ranges.
 It promises true mass-production potential.

16. THANK YOU