DRS Technologies has designed and delivered Thermal Weapon Site (TWS) and Driver's Viewer Enhancer (DVE) system using its U3500 (320x240) and U6000 (640x480) 1-mil detector arrays. The detectors are modified to enhance its manufacturability, thermal time constant, package life time, and its reliability under shock and vibration to meet TWS and DVE requirements. The U6000 array operates at 30 Hz frame rate with NETD less than 50 mK normalized to F/1.0 optics. At a saving to the system weight and power, these arrays operate from -40°C to +65°C without the aid of a TE cooler. This is accomplished through a combination of sensor calibration and smart ROIC architecture.
To improve its capacity to meet customer needs, DRS Infrared Technologies began technology transfer of the VOx uncooled FPA process from its Anaheim facility to its Dallas facility in the Fall of 2002. The new facility delivered its first U3000 arrays (320x240, 51μm pitch) three months after the VOx deposition system was installed, and produced over 300 units of U3000 per month just twelve months after beginning the transfer. Process enhancements and tool upgrades have enabled excellent control of the microbolometer process. Today, this line selectively fabricates arrays with NETD varying from 30mK to 80mK in 15mK bins with less than 30 ms time constant. The same arrays also have low defect density of less than 2% dead pixels and no more than one row and one column out. The arrays are packaged in imager or radiometer (F/1.4) packages. DRS also transferred small and large format arrays with 25μm pitch under the PEO-Soldier Sensor Producibility to the Dallas facility. Production of the 25μm pitch devices is currently more that 100 units per month and is ramping up to meet customer demand. This paper reports on production progress on the U3000s and the status of U3500 and U6000 25μm pitch array.
DRS has developed and demonstrated a family of miniaturized, low-power uncooled infrared focal plane camera products integrated with our 1-mil pixel size 640 x 480 and 320 x 240 uncooled infrared focal plane arrays (UIRFPA). The UIRFPA cameras operate from -40°C to +55°C without UIRFPA temperature regulation using our patented TCOMP sensor concept. Furthermore, they are software based, with significant memory and signal processing overcapacity, which supports significant camera setup reconfigurations without having to undergo camera firmware and hardware modifications. The elimination of the UIRFPA temperature regulation requirement results in reduced sensor power and prompt sensor turn-on. The new 320 x 240 camera weighs less than a quarter pound (including batteries and a 23 mm aperture F/1.2 optic), and dissipates approximately one watt when operated at a full 60 Hz frame rate. The 640 x 480 camera dissipates about two watts when operated at a TV compatible 30 Hz frame rate. This paper describes the UIRFPA camera products, their features and capabilities, and their key performance characteristics. Illustrative examples of thermal image quality are also included.
DRS has previously demonstrated and reported a concept for operating uncooled infrared focal plane arrays (UIRFPA) without the need for UIRFPA temperature regulation. DRS has patented this proprietary technology, which DRS calls TCOMP. TCOMP is a concept that combines an operating algorithm, a sensor architecture and a sensor calibration method, which allow pixel response and offset correction to be performed as a function of the UFPA sensor's operating temperature, thereby eliminating the need for the UIRFPA temperature regulation that would be required otherwise. As a result of the elimination of the temperature regulation requirement, the sensor turn-on time for high performance imaging can be significantly reduced, sensor power is significantly reduced, and the need for stray thermal radiation shields is effectively eliminated. The original TCOMP technique was demonstrated in 1998. Since then DRS has made significant improvements in both the TCOMP algorithm and the calibration process. This paper describes the patented TCOMP concept, presents the results of analysis of the improved TCOMP concept, and provides sensor level data of UIRFPA/sensor performance with the improved TCOMP algorithm.
DRS has been conducting several significant ongoing efforts to improve the producibility of its uncooled IR focal plane products. Those efforts are described in this paper. First, pixel dimensions are being reduced by a factor of two or mroe, while maintaining NETD performance levels fully comparable to that of the previous standard approximately 50-micron pixel size. The results for a given array size is smaller die size and mroe die per wafer. Second, DRS is transitioning UIRFPA production from its 5-inch wafer diameter process facility in Anaheim, CA to its 6-inch wafer diameter process facility in Dallas, TX, which results in more die per wafer and in enhanced wafer throughput capacity. Furthermore, the Dallas UFPA production facility is being tooled for a smooth future transition to 8-inch wafer processing. Third, a new ceramic UIRFPA vacuum package has been developed, which has lower material cost, fewer parts and assembly operations, and is lighter significantly weight than the current standard metal package. Since packaging is inherently the most expensive part of UIRFPA manufacture, packaging producibility improvements can provide significant cost leverage. Fourth, DRS is developing a batch-mode UIRFPA vacuum bake and sealign system, which will achieve significant throughput capacity gains, reduce touch labor requirements, and reduce production cycle times.
DRS (formerly Boeing) has completed the development and demonstration of a 25-micron pixel size 640x480 VOx microbolometer uncooled IR focal plane product, the U6000. The U6000 incorporates several advanced features to enhance its performance and functional capabilities. A parallel six- bit Smart-Sensor data bus provides external command and data interface capability between the sensor and the focal plane. This includes on chip 6-bit pixel offset correction, detector bias selection and regulation, programmable signal gain, interlaced and non-interlaced output video format selection, signal integration time selection and input referred global offset selection capabilities. The U6000 also includes a high resolution on-chip temperature measurement that is incorporated into the single channel output video during horizontal blanking. This paper describes the U6000's functional capabilities, and provides U6000 functional validation and performance data.
This paper provides a review of the significant progress achieved in uncooled VO microbolometer LWIR focal plane and sensor technology at The Boeing Company during the last four years. When Boeing (formerly Rockwell) first introduced its first 320x240 uncooled FPAproduct in 1996, the U3000, it had a specified product NETD <0.1 K (F/i). Today, as a result of on-going improvements in VOx microbolometer design, processes and materials, the U3000 product is an established workhorse that is achieving an F/i NETD in the range of 0.033 to 0.040 K. The new U4000 320x240 product, that is being introduced by Boeing this year, has already demonstrated an F/i NETD <0.023 K at a 60 Hz frame rate, while having a thermal time constant <0.025 sec. In addition, significant progress has been made with innovative uncooled sensor operating concepts. Boeing has demonstrated its "TCOMP" response and offset compensation concept, which allows the uncooled IRFPA to operate without the need for temperature regulation. The elimination of the need for temperature regulation also means that uncooled LWIR imaging sensors can now have essentially instant-on operating capability, while requiring significantly less power. Spatial F/i NETD as low as 0.027 K, which is a measure of the level of spatial pattern noise in the displayed sensor image, has been demonstrated with a U4000/TCOMP sensor, and TCOMP has already been demonstrated over an at least 30 K calibration range.
Jeffery Heath, Bill Meyer, James Woolaway, William Parrish, Dieter Lohrmann, Gwendolyn Newsome, Adrian Inosecu, John Monson, Christopher Rau, Philip Howard, Chuan Li
This paper describes two camera systems based on the advanced 160 X 128 uncooled micro-bolometer FPAs. The UL3 ALPHA camera is in production and takes advantage of the patented bias equalization FPA performance to produce the world's smallest IR production camera. UL3 ALPHA weighs less than 195 grams, uses 1.5 W of power (nominal) and has a overall dimensions of 4.3 cm X 4.3 cm X 7.5 cm. ULS ALPHA production cameras have demonstrated 62 mK NEdT operation with over 99% operability.
Jeffery Heath, Glenn Kincaid, James Woolaway, William Parrish, Dieter Lohrmann, Gwendolyn Newsome, Adrian Inosecu, John Monson, Christopher Rau, Philip Howard, Chuan Li
This paper describes the UL3 camera system based on the advanced 160 X 128 uncooled micro-bolometer FPA. The UL3 camera takes advantage of the patented bias equalization FPA performance techniques to produce the world's smallest IR camera. The UL3 camera weights less than 2.3 ounces, uses less than 600 mW of power, and has overall dimensions of 3 cm X 3 cm X 6 cm. The architectures feature an approach that integrates the required system functions on ASICs and FPGAs rather than including discrete components and microprocessors.
Jeffery Heath, Glenn Kincaid, James Woolaway, William Parrish, Dieter Lohrmann, Gwendolyn Newsome, Adrian Inosecu, John Monson, Christopher Rau, Philip Howard, Chuan Li
This paper presents background and measured performance data on a novel, low cost, high performance readout integrated circuit (ROIC) for microbolometer uncooled detector applications. The array is designed to offer better than 80mK NEdT performance using f/1.8 optics. The design incorporates advanced on-ROIC signal processing electronics that allow bolometer element non-uniformity control over a wide range of ROIC substrate temperatures. The small format array is ideally suited for high volume low-cost production applications.
This paper describes Boeing's next-generation 320 X 320 uncooled IR focal plane product. The basic objectives have ben to at least double focal plane performance, improve focal pane operating stability, and significantly enhance the control interface between the focal pane and the camera. All of these basic objectives have been achieved. Focal plane temporal NETD equals 0.028 degrees C has been demonstrated at a frame rate of 60 Hz on the first lot of UFPAs produced, as well as a worst-case spatial NETD < 0.016 degrees C measured over 10 degrees C temperature calibration range. Operating stability improvement has been successfully demonstrated. The design has validated a 'smart sensor' UFPA/camera control interface that provides externally programmability of on-chip signal gain, on-chip pixel offset compensation, on-chip detector bias regulation, precision on-chip temperature measurement, and a 16 test- point Built In Test function. Based on Lot-1 test results, the next lot, which is now in wafer processing, is expected to achieve NETD < 0.02 degrees C at a 60 Hz frame rate. With an improved microbolometer Thermal Isolation Structure, currently in development at Boeing, NETD < 0.010 degrees C can be demonstrated before the end of this year.
This paper reviews Boeing's progress, over the last three years, in Vanadium Oxide (VOx) uncooled microbolometer focal plane (UFPA) technology and product development. Boeing's UFPA product technology is described, including product capabilities and performance. Focal plane NETD equals 31 mK (F/1), at a 30 Hz sensor frame rate, has been demonstrated on the U3000 320 X 240 UFPA product. At a 60 Hz frame rate, the NETD (F/1) achieved on production U3000 UFPAs is typically less than 60 mK, and spatial pattern noise levels are consistently less than 33 mK after sensor level gain and offset compensation. Key improvements in VOx tin- film technology have been the achievement of a Temperature Coefficient of Resistance (TCR) approximately 3%, and the achievement of microbolometer resistance uniformity of approximately 1/3% ((sigma) /(mu) ) on the UFPA die. Looking into the future, this year Boeing expects to achieve NETD approximately 20 mK (F/1) with very low pattern noise, and within the next three years higher density 640 X 480 focal planes will be demonstrated with essentially equivalent NETD performance. Large high density uncooled LWIR focal planes, combined with low NETD, will make UFPA technology a prime candidate for higher performance FLIR applications.
The ULTRA (Uncooled, Low cost, Technology Reinvestment Alliance) Consortium, consisting of the Honeywell Technology Center of Honeywell Incorporated, the Autonetics Missile Systems Division of Rockwell International Corporation, Inframetrics Incorporated, and the New Jersey Institute of Technology, has been formally working together over the past year in an effort to develop, manufacture and sell industrial and military sensors and components incorporating silicon microbolometer uncooled focal plane array (UFPA) technology. Towards that end, Rockwell has been actively engaged in developing the UFPA component, with assistance from Honeywell, with the intention of being a merchant supplier of the UFPA. Inframetrics has been developing subsystems required to construct and characterize a prototype sensor, and NJIT is designing a Multi-Wavelength Imaging Pyrometry system around the performance of the uncooled prototype sensor. TRP Office funding administered by ARPA has been key to the significant advances made over the course of the year in this program. This paper will describe both the UFPA component specification and the prototype sensor. It will give a architectural overview of the detector array, with the anticipated performance characteristics. Multiplexer design and simulation, and array processing, will be addressed. A description of the array packaging, interface requirements, and unique design considerations will be provided. Anticipated and actual component performance will be explained and contrasted. The background of the sensor development will be presented. An overview of the camera architecture will be given, with some discussion of trade-offs in subsystem design of the sensor. Specific emphasis is placed on the radiometric evaluation of the sensor.
A high-performance 5-μm 640 X 480 HgCdTe/CdTe/Al2O3 infrared focal plane array (FPA) that offers full TV-compatible resolution with excellent sensitivity at temperatures below 120 K has been developed. Mean FPA D* at 95 K and background of 1014 photons/cm2 s is background-limited at ~1 x 1012 cm Hz1/2/W for the typical mean quantum efficiency of 60 to 70%. The key technology making this large, high-sensitivity device producible is the epitaxial growth of HgCdTe on a rugged CdTe-buffered sapphire substrate. Mean camera noise-equivalent temperature difference NEΔT of 13 mK has been achieved at ≤ 120 K operating temperature and 3.4- to 4.2-μm passband; this is about an order of magnitude better than similar currently available cameras, which use PtSi FPAs and require cooling to ≤ 77 K to maintain performance at low scene temperatures.
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