The Broadband Radiometer (BBR) is an instrument being developed for the ESA EarthCARE satellite. The EarthCARE mission objective is aimed at providing a better understanding of the Earth’s clouds, aerosols and radiation interactions. This will be done by the use of four instruments on the EarthCARE satellite. One of them is the BBR instrument, for which the detectors development is under the responsibility of INO.
The BBR detectors use the VOx-based uncooled microbolometer detector technology developed by INO and its partners. INO developed a custom linear 30-pixel microbolometer focal plane array (FPA) on 100-µm pixel pitch. The linear array is hybridized with an external readout circuit in an assembly that further includes a circuit card assembly providing signal routing, passive components, and an interface connector to the instrument electronics. The assembly is completed by a mechanical base plate and cover for alignment with the instrument telescope.
To ensure a broadband flat response, the linear array is coated with gold-black. INO’s approach included manufacturing of prototypes early in the development to confirm the suitability of INO’s technologies for the application. A gold-black deposition facility has been developed and built at INO to meet the needs, not only of the BBR instrument, but of future broadband applications as well. The gold-black facility was commissioned and the process parameters were subsequently optimized to achieve deposits meeting the requirements of the BBR detectors. Given the gold-black facility’s capabilities in terms of control and monitoring, the process and resulting deposits can be adapted to other specific needs. Pixel definition of the coated FPA is ensured by ablating the gold-black material by a high-resolution micromachining system, which was designed, developed and implemented in an INO’s cleanroom laboratory. INO’s capabilities for laser micromachining cover a wide range of applications.