At present, almost all the IR detectors respond to the unique spectrum range. Unfortunately for the system developer, terms such as “multispectral” are often misunderstood. The term multispectral refers to the ability of an imaging system to detect electromagnetic energy in at least two or more individual spectral bands, such as visible and IR.
Advancements in cooled IR detector technology have created opportunities for a wide variety of applications, including hyperspectral remote sensing, space imaging, and surveillance. Multi-spectral imaging is a key technology used to provide a soldier with the information he needs to perform his mission, in a clear, efficient and intuitive manner. Such detectors offer sensitivity to the degree that users can distinguish individual species of trees from space or even identify moving camouflaged tanks from great distances. Until now, only cooled IR cameras have been used for hyperspectral imaging and remote sensing applications, as they require an extraordinarily high sensitivity that can be provided by only cryogenically cooled IR detectors. Uncooled IR technology is not yet developed to work for remote sensing application or hyperspectral imaging applications. However, in the next few years, IR detector manufacturers may develop an uncooled IR detector that can be used for remote sensing. Therefore, hyperspectral imaging and remote sensing provides opportunities to IR detector/imaging market in future.
Moreover, there is a latent need for single affordable IR detectors, which are sensitive to multiple wavelengths for applications like food scanner or automotive applications. This technology is still in its nascent stage and expensive, thus used for very high-end applications (mostly in research laboratories), and hence is not suitable for mass production. In addition, there is no uncooled IR detector sensitive to two or more spectrum ranges.
Thin film coatings play a vital role in multi-spectral detection. Discrete bandpass filters are being deposited on planar substrates which can be bonded together to make multi-spectral filter mosaic assemblies placed in front of a sensor. To reduce size and weight, multiple filters can be deposited on a single surface via traditional semiconductor photolithography techniques. These advances allow for miniaturization, which enables multi-spectral imaging in helmet—or eyeglass-mounted sensors, weapons scopes, small, remote vehicles and satellites.
Some companies like BAE Systems (U.K.), Honeywell (U.S.) and Banpil Photonics (U.S.) have introduced products which operate in multiple spectral range but these products are currently high priced with limited applications. As more and more companies launch their products in this segment, the market demand is expected to increase with wider range of applications.
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