Uncooled Thermal Imaging with Thin-Film Ferroelectric Detectors

摘要

The uncooled infrared imaging revolution began when ferroelectric detectors based on barium strontium titanate (BST) demonstrated NETDs less than 100mK at prices sufficiently low for commercial applications. Although this technology produces unsurpassed image quality, it has been largely supplanted by microbolometer technology, which can be fabricated in smaller pixel sizes, leading to smaller systems, and which produces a monolithic device using simpler fabrication processes than hybrid BST devices.In order to achieve the superior image quality of BST and at the same time benefit from the simpler manufacturing process and performance improvement potential of microbolometers, we have developed thin-film ferroelectric (TFFE) detector arrays. This technology has been under development for a decade, and it has lived up to its promise in spite of development difficulties. The image quality is superior to BST because of improved MTF, and it is superior to bolometers because of low spatial noise. TFFE arrays operate in all existing BST systems. The detectors require no temperature stabilization, and a single-point room-temperature calibration suffices for operation from -40°C to +85°C and beyond. Dynamic range is improved relative to BST by a factor of ten or more, and the optical local-area processing enables simultaneously viewing of detail in parts of the scene that differ by hundreds of degrees. It is also immune to sustained direct exposure to the sun.