5 August 2002 High-sensitivity 25-μm microbolometer FPAs
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Raytheon Infrared Operations (RIO) has achieved a significant technical breakthrough in uncooled FPAs by reducing the pixel size by a factor of two while maintaining state-of-the-art sensitivity. Raytheon has produced the first high-quality 320x240 microbolometer FPAs with 25 micrometers pitch pixels. The 320 x240 FPAs have a sensitivity that is comparable to microbolometer FPAs with 50 micrometers pixels. The average NETD value for these FPAs is about 35 mK with an f/1 aperture and operating at 30 Hz frame rates. Good pixel operability and excellent image quality have been demonstrated. Pixel operability is greater than 99% on some FPAs, and uncorrected responsivity nonuniformity is less than 4% (sigma/mean). The microbolometer detectors also have a relatively fast thermal time constant of approximately 10 msec. This state-of-the-art performance has been achieved as a result of an advanced micromachining fabrication process. The process allows maximization of both the thermal isolation and the optical fill-factor. The reduction in pixel size offers several potential benefits for IR systems. For a given system resolution (IFOV) requirement, the 25 micrometers pixels allow a factor of two reduction in both the focal length and aperture size of the sensor optics. The pixel size reduction facilitates a significant FPA cost reduction since the number of die printed on a wafer can be increased. The pixel size reduction has enabled the development of a large-format 640x480 FPA array. Raytheon has produced arrays with very good sensitivity, operability, and excellent image quality. These FPAs are applicable to wide-field-of-view, long range surveillance and targeting missions. Raytheon is also developing a high performance 160x128 FPA that is designed for applications where miniaturization and temperature invariance are required as well as low cost and low power.
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Daniel F. Murphy, Daniel F. Murphy, Michael Ray, Michael Ray, Richard Wyles, Richard Wyles, James F. Asbrock, James F. Asbrock, Nancy A. Lum, Nancy A. Lum, Jessica Wyles, Jessica Wyles, C. Hewitt, C. Hewitt, Adam Kennedy, Adam Kennedy, David Van Lue, David Van Lue, John Steven Anderson, John Steven Anderson, Daryl Bradley, Daryl Bradley, Richard Chin, Richard Chin, Thomas Kostrzewa, Thomas Kostrzewa, "High-sensitivity 25-μm microbolometer FPAs", Proc. SPIE 4721, Infrared Detectors and Focal Plane Arrays VII, (5 August 2002); doi: 10.1117/12.478857; https://doi.org/10.1117/12.478857


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