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Very Small Pixel Uncooled Longwave Read-Out Integrated Circuit for Enhanced Sensor SWAP and Range Performance



OBJECTIVE: Develop a read-out integrated circuit (ROIC) for use on an uncooled longwave infrared (LWIR) bolometer focal plane array (FPA) based sensor having a pixel pitch of 6–8.5 microns.This will enable lower size, weight, and power (SWaP), higher resolution uncooled LWIR sensors for Soldier borne and vehicle mounted applications.

DESCRIPTION: The Army makes extensive use of uncooled bolometer sensors throughout its air, ground, and Soldier portfolios.In nearly all cases there is a SWaP concern, and for many applications it is paramount.A way to increase sensor performance for a given SWaP is to decrease the pixel pitch.The current standard pitch is 12 μm.DoD and industry investments are being made to improve pixel design to enable small pixels, but currently no ROICs exist to take advantage of these investments. As the pixel gets smaller, it becomes more of a challenge to fit appropriate ROIC circuitry within the available space.To overcome this hurdle, hybrid or fully digital circuit architectures may need to be used, perhaps in conjunction with novel physical architectures and fabrication techniques.However, the most desirable approaches will include as many as possible of the following features: • ≥ 120 Hz full-frame frame rate, preferably ≥ 240 Hz; windowing to even higher frame rates • Very low power, suitable for small autonomous platform or Soldier-borne applications • Resolution of ≥1280×1024 pixels • Bolometer-limited noise performance (ROIC does not significantly degrade noise performance of bolometer) • Low-cost fabrication techniques and processes • Very high intra-scene temperature dynamic range

PHASE I: The proposer shall design and model a small pixel ROIC for uncooled LWIR bolometer sensor applications that supports as many of the desired features listed above as possible.

PHASE II: The proposer shall fabricate a small pixel ROIC based on phase I results.At a minimum, results from a device verification test (DVT) for fabricated ROIC wafers must be presented.Collaboration with one or more bolometer manufacturer during this phase is highly encouraged to ensure that the ROIC will support realistic bolometers (e.g. physical form factor, pixel resistivity, etc).

PHASE III: With an industry partner, determine an appropriate transition or upgrade path to an Army or DoD customer.Deliver prototype camera systems with 1280×1024 or better resolution for investigation of a variety of problems of commercial and military relevance to the Army where high performance is required in a low SWaP-C package.It is expected that the proposer will partner with one or more bolometer manufacturer during this phase to fabricate appropriate bolometers on the ROIC and build of camera.

KEYWORDS: ROIC, readout integrated circuit, uncooled LWIR, bolometer, thermal, infrared


1. Rogalski, Martyniuk, Kopytko, “Challenges of small-pixel infrared detectors: a review,” Rep on Prog in Physics, Vol 79, 4 (2016); 2. Mount, “DRS successfully demonstrates the first 10-micron high performance infrared sensors,”; 3. Lohrmann, Littleton, Reese, Murphy, Vizgaitis, “Uncooled long-wave infrared small pixel focal plane array and system challenges,” SPIE Optical Engineering, Vol 52, 6 (2013); 4. Holst, “Imaging system performance based upon Fλ/d," Optical Engineering, Vol 46, 10 (2007)

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