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Dexter Research pioneered the field of infrared thermopile detectors, and our technology continues to lead the industry. Competitive benchmarks tell the story.
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Infrared Thermopile Detectors – Technical Library
Application Briefs
A Simple DC Radiometer
This brief explains the basic principles of remote temperature measurement using thermopiles. Download PDF (116 KB). Also available for download as a Mathcad document (31 Kb).
Temperature Compensation of a DC Radiometer
Since a thermopile is an array of thermocouples, the temperature of the cold junction of the thermocouple must be known to provide an accurate temperature measurement. This brief describes a method for dealing with a variation in the cold junction temperature. Download PDF (63 Kb).
Emissivity Correction for a Radiometer
The optical power emitted by a target will depend on its emissivity and temperature. A simple technique to take into account the change in sensitivity is described. Download PDF (109 Kb).
Variations in Calibrations of Radiometers Using Cut-on Optical Filters
The amount of optical energy falling on the thermopile will depend on the transmission characteristic of the filters used as the window in the detector. This brief discusses the effect of the variation in the bandwidth of the filter in the calibration of a radiometer. Download PDF (116 Kb).
Thermopile Time Constant Determination
The methods for measuring the time constant of a thermopile are discussed. Download PDF (73 Kb).
Aperture Options
The field of view (FOV) may be modified inside the detector package using apertures. This is also useful in eliminating crosstalk in multi-channel detectors. On TO-5 packages, the FOV may be modified by customizing the internal aperture hole size. This also defines the amount of energy coming into the package and subsequently falling on the detector active area. Download PDF (96 Kb).
Effects of Encapsulating Gas on Thermopile Detectors
Most thermopiles are hermetically sealed with an inert gas in the package at one atmosphere pressure. The selection of encapsulating ga allows customization of detector output sensitivity and time constant without affecting other parameters such as resistance or noise. Download PDF (150 Kb).
Technical Background
Introduction to Thermopile Detectors
The basic principles and nomenclature of thermopile detectors are explained. There is also an explanation of the types of thermopile detectors available from Dexter Research, as well as an abbreviated list of the ever-growing applications for thermopile detectors. Download PDF (93 Kb).
Thermopile Detector Comparison: Thin Film vs. Silicon
Typical amplifier circuits for use with thermopile detectors are shown. Download PDF (76 Kb). See also: Example Amplifier Circuits (PDF, 95 Kb).
Detector Normalized Angular Response
The normalized angular response for a thermopile detector is shown. Download PDF (13 Kb).
Detector Normalized Response as a Function of Frequency
The frequency response of thin film and silicon-based thermopiles are shown for sinusoidally modulate radiation. Download PDF (89 Kb).
Blackbody Spectral Radiance
Calculation of the blackbody radiance for three spectral regions of commonly used filters is given. Download PDF (169 Kb).
Detector Signal Calculation
The calculation of a detector signal in a reflective optical system is shown. Download PDF (74Kb).
Standard Windows and Filters
Standard optical filters, wide-band and uncoated, are compared in an informative table. Download PDF (113Kb).
Typical Spectral Characteristics
Typical spectral characteristics of select optical windows (wide-band pass) are graphed in transmission curves for select filters. Download PDF (41 Kb).