AAS-930-164B Datasheet, PDF (4/4 Pages) Amphenol Corporation – Thermopile IR Sensor Applications

Measurement Block Diagrams
Sensitivity
Glossary of Terms
The following are basic terms and symbols used
to define the characteristics of a thermopile IR
detector.
• The heat source is the standard blackbody
furnace to be set at a desired temperature
• There should be no other heat source within
F.O.V. of the detector
• The opening aperture size of the standard
blackbody furnace is always same
• The ambient temperature is always same
Field of View
Bias Voltage [V]
Application of an electrical voltage to make operate
a thermopile detector in a desired way.
• Maximum bias : A bias voltage which yields
maximum signal output
• Optimum bias : A bias voltage which yields
maximum S/N ratio output
Black Body
A source of infrared whose output can be predicted
accurately by Planck`s law.
Cutoff Wavelength [um]
The wavelength at which the specific detectivity (D*)
has decreased to one half of its peak value.
Field of View [FOV, SR]
The solid angles through which the detector can see
given object.
Linearity
How well the output signal tracks the infrared power.
• The heat source is a movable IR point source
• There should be no other heat source within F.O.V.
of the detector
• The ambient temperature is always same
Time Constant Measurement
Noise Equivalent Power [NEP, W]
A minimum signal power the detector can
detectable. This is a function of source temperature,
chopping frequency, noise equivalent bandwidth,
field of view and ambient temperature.
Responsivity [Rv, V/W]
A thermopile detector sensitivity defined as the ratio
of the thermopile detector output signal generated
in response to a unit input radiant power.
Specific Detectivity [D*, cm(Hz)^1/2/W]
The detectivity normalized by detector responsive
area and noise bandwidth, so it is a convenient way
to specify and compare detector performance.
• The heat source is a IR point source
• The time constant shall be decided by the time
required 63% of the detector output voltage
• The ambient temperature is always same
Spectral Response
How the responsivity varies with the wavelength of
the infrared power.
Time Constant [ms]
A term to describe the detector response speed.
This depends on the thermal resistance and the
thermal capacitance of the thermopile IR detector.
Amphenol
Advanced Sensors
www.amphenol-sensors.com
© 2015 Amphenol Corporation. All Rights Reserved. Specifications are subject to change without notice.
AAS-930-164B - 06/2015