THERMAL SENSOR WITH INFRARED ABSORPTION MEMBRANE INCLUDING METAMATERIAL STRUCTURE

摘要

A thermal sensor includes an array of pixels, each having a membrane mounted on legs over a reflector, forming a Fabry-Pérot cavity. Each membrane includes an infrared (IR) absorbing material that defines multiple spaced-apart openings separated by micron-level distances that decrease thermal capacity and increase IR absorption of the membrane. Regular pitch distances between adjacent openings provides narrowband IR absorption, with pitch distances below 7.1µm facilitating the detection of IR radiation wavelengths below 7.5µm. Multispectral thermal imaging is achieved by arranging the pixels in repeated groups (superpixels), where each superpixel detects the same set of IR radiation wavelengths. Thermal imaging devices include thermal sensors, IR lenses and device control circuitry arranged in a camera-like manner. A methane leak detection system utilizes two multispectral imaging devices positioned to image a wellhead from two directions, and a system controller that generates spatial and spectral information describing methane plumes using the image data.