As humans, we are capable of sensing wavelengths of electromagnetic radiation in the ranges between 740nm to 380nm, otherwise known as the Visible Light Spectrum.
This has served us well over the past millennia, however, in today’s technologic advancing society, we are becoming aware of the usefulness of being able to sense wavelength outside of this range.
Wavelengths regions such as Infra-Red (700nm to 1mm), Ultra Violet (400nm to 10nm) and X-Rays (0.01nm to 10nm) have all proved their worth in day to day inspection, maintenance and medical applications.
However, to be able to capitalize on the benefits of sensing other wavelength regions, we need to take advantage of various technologies to enhance our capability to make other regions visible.
Related article: Electromagnetic Spectrum
Applications where Infra-Red is best applied, are those applications that require a difference in temperature to be detected. This is a result of most thermal energy being emitted in the wavelengths that are categorized as Infra-Red.
From Night Vision to Meteorology to Art Conservation, Infra-Red has a broad application range for which some form of thermal-infrared imaging is required.
An Infra-Red camera provides a capability whereby infra-red energy is detected, and converted into an electronic signal. That electronic signal is then displayed on a monitor and presented in a format that is visible to the human eye.
Related article: Microbolometer
There are many different forms of Infra-Red detector depending on the wavelength and requirement of information, however, a common detector is known as a ‘Microbolometer’.
A microbolometer is an electromechanical device which can detect infrared radiation with wavelengths between 2 and 14um (most commonly these devices are designed to detect IR with wavelengths between 7 and 14um). The device consists of an array of pixels containing an IR absorbing material.
The resistance of this material correlates to the wavelength detected, it is this difference in resistance across an array that produces the electronic signals required to produce an interpretation visible to the human eye.
For more information about how Infrared sensors work, or about applications to which they are suited, click here.