Infrared detector

1. An Introduction to Infrared Detector
An infrared detector is
a detector that reacts to
infrared radiation (IR) .
Prototype of high-speed infrared detector installed on
the PIONIER instrument at ESO’s Paranal Observatory.

2. Infrared radiation (IR), sometimes called infrared light, is
electromagnetic radiation (EMR) with wavelengths
longer than those of visible light.
Infrared radiation was discovered in 1800 by astronomer
Sir William Herschel who discovered a type of invisible
radiation in the spectrum lower in energy than red light,
by means of its effect on a thermometer.

3. The two main types of detectors are thermal
and photonic (photodetectors).
A thermal Infrared Detector
A photodetector

4. The Working Principle of Infrared Sensors
The physics behind infrared sensors is governed by three laws:
1.Planck’s radiation law: Every object at a temperature T not equal to 0 K emits
radiation
2.Stephan Boltzmann Law: The total energy emitted at all wavelengths by a black
body is related to the absolute temperature
3. Wein’s Displacement Law: Objects of different temperature emit spectra that
peak at different wavelengths
How it’s work?

5. Advantages of Infrared Detector
➨ It provides secured communication due to line of sight or point-to-point mode of
communication.
➨The battery used in infrared devices last for long duration due to lower power
consumption.
➨Infrared motion sensors detect motion in daytime and nighttime reliably.
➨The sensor does not require any contact with the product to be sensed. The infrared
devices are more appropriate for targets which are close than 10 mm.
➨Infrared devices can measure distance to soft objects which may not be easily
detected by ultrasound.
➨They are physically smaller in size and are more affordable.
➨It has response time faster than thermocouple.

6. Disadvantages of Infrared Detector
➨ Infrared frequencies are affected by hard objects (e.g. walls, doors) , smoke,
dust, fog, sunlight etc. Hence it does not work through walls or doors.
➨ Infrared waves at high power can damage eyes.
➨ In monitor & control application, it can control only one device at one time.
Moreover it is difficult to control things which are not in LOS (Line of Sight). It
requires line of sight between transmitter and receiver to communicate.
➨ It supports shorter range and hence it performance degrades with longer
distances.
➨ It supports lower data rate transmission compare to wired transmission.

7. USES OF IR Detector
• IR detector include thermal
detection using bolometers,
thermocouples and
pyroelectric detectors,
photon detection by
extrinsic and intrinsic
semiconductor
photoconductors,
photodiodes and
photoemitters, and infrared
imaging using these
devices.

8. • IR source (transmitter) is used to emit radiation of
required wavelength.
• This radiation reaches the object and is reflected
back.
• The reflected radiation is detected by the IR receiver.
• The IR Receiver detected radiation is then further
processed based on its intensity. Generally, IR
Receiver output is small and amplifiers are used to
amplify the detected signal.

9. The Key Applications of Infrared Technology
• Night Vision
• Infrared Astronomy
• Infrared Tracking
• Art History and Restoration
• Climatology
• Water Analysis
• Petroleum Exploration etc. Infrared Detector use on Climatology

10. A pseudocolor image of two people taken in
long wavelength infrared (body-temperature
thermal) light.
This infrared space telescope image has (false-
color) blue, green and red corresponding to 3.4,
4.6, and 12 μm wavelengths, respectively.

11. THANK
YOU