Infra-red cameras and detectors are like digital cameras, only the pixel system is sensitive to the infrared spectrum instead of the visible light spectrum; a lower frequency than visible light in the Electromagnetic Spectrum. Also, putting a box around the pixel system (chip), as in a photo camera, won’t work because infrared energy, which is heat, will come right through the sides of the box. Also, all high end IR cameras and detectors operate at cryogenic temperatures, so the pixel system and surrounding items must be instantly cooled down, especially for military applications. We make thin walled metal shells that go over the pixel systems upon which the lenses are mounted called Coldshields. They must be metal and thin walled to cool down quickly. The outside surfaces must be gold plated to reflect IR energy coming in from the sides, and the interior surfaces must be blackened to absorb IR energy coming through the lens at an angle. Also, the interior surfaces must have complex geometric shapes with extremely accurate dimensions to achieve the “3 bounce rule” for dissipating any stray IR radiation entering the lens on an angle, so the pixel array only sees what the camera or sensor is aimed at, and is not blurred by stray radiation.
We make coldshields to customer’s designs per the attached photo. We also have a reflectance meter so we can record and send to our customers the IR reflectance data of the exterior gold coating and the IR absorbance of the interior black coating, both of which we supply.