Industrial and petrochemical facilities present unique challenges for fire protection and safety. Typical scenarios include detection of an unintended fire in a scene, wherein the scene also includes a flare stack in the background. Maintaining a high level of process and plant safety is a critical concern. In this paper, we present a failsafe industrial flame detector which has significant performance benefits compared to current flame detectors. The design involves use of microbolometer in the MWIR and LWIR spectrum and a dual band filter. This novel flame detector can help industrial facilities to meet their plant safety and critical infrastructure protection requirements while ensuring operational and business readiness at project start-up.
Unmanned air vehicles (UAVs) today are mostly used for reconnaissance and sometimes weapons delivery. Remote sensing of chemical-biological (CB) agents is another beneficial use of UAVs. While remote sensing of CB agents can be done by LIDAR spectroscopy, this technology is less spatially precise and less sensitive than actual measurements on a collected sample. One family of UAVs of particularly unique benefit for CB sampling and in-flight analysis is the Honeywell family of Organic Air Vehicles (OAVs). This vehicle with its ability to hover and stare has the unique ability among UAVs to collect and analyze chem-bio samples from a specific location over extended periods of time. Such collections are not possible with other micro-air-vehicles (MAVs) that only operate in fly-by mode. This paper describes some of the Honeywell OAV features that are conducive to CB detection.
Uncooled thermal infrared sensors require to be operated in an ambient gas pressure of about 50 mTorr or less to avoid sensitivity being reduced by thermal conduction through the gas. Although sealed packages have been developed which can retain a sufficiently low internal pressure for many years, the packaging process (cleaning, assembly, pumping, baking, getter firing, sealing) and materials add significant cost and weight. Lower cost it the major reason for the development of uncooled arrays, and low weight is essential for many applications (e.g. unmanned aerial vehicles, helmet mounted applications). In response to these needs, Honeywell has developed a silicon 'Integrated Vacuum Package' (IVP) process which produces a low-cost lightweight (0.2 gram) compact vacuum package by a wafer-scale process. The IVP process basically consists of bonding a silicon 'topcap' wafer to the array wafer, to produce a bonded double-wafer with multiple arrays protected in individual vacuum packages. The double- wafer may be easily handled without damage to the protected arrays, and diced into individual dies using normal silicon dicing techniques. It has been found helpful to use an etched evacuation via, which allows wafer bonding, pumping, baking and sealing to be performed in separate stages, at their different optimum times and temperatures. The IVP process will be described, and packages suitable for linear and two- dimensional uncooled arrays will be reported, with performance and lifetime measurements.
Honeywell has developed a high-speed infrared emitter pixel and implemented the design on two 512 X 512 scene projector array designs. This pixel is a faster version of the original Gen-III Gossamer pixel implemented on previous 512 X 512 arrays. The new pixel has a 10% - 90% rise time under 4 milliseconds, enabling a dramatic increase in scene projection frame rates over currently available arrays. Full array frame rates of 200 Hz are not practical and subarrays can be driven up to 400 Hz. In spite of the increased speed, the array still maintains high brightness using the same CMOS electronics. This design and other array developments will be described.
In the past year, Honeywell has developed a 512 X 512 snapshot scene projector containing pixels with very high radiance efficiency. The array can operate in both snapshot and raster mode. The array pixels have near black body characteristics, high radiance outputs, broad band performance, and high speed. IR measurements and performance of these pixels will be described. In addition, a vacuum probe station that makes it possible to select the best die for packaging and delivery based on wafer level radiance screening, has been developed and is in operation. This system, as well as other improvements, will be described. Finally, a review of the status of the present projectors and plans for future arrays is included.
In 1991 the Honeywell Technology Center began the development of large area 2D microemitter arrays for IR scene projection. Since then, 5 different types of 512 X 512 or larger arrays have been fabricated, all in current use. This paper will review the status, properties, and applications of these arrays. Pixel and array improvements which will lead to ultralow power consumption, very high performance, very fast 1024 square arrays are under development. A number of these efforts are described.
Resistive emitter arrays are formed via the fabrication of microemitters on Si CMOS electronics. These IR emitter arrays using microstructures have been developed at Honeywell to project scenes for a wide range of applications. A new array which has been fabricated has a size of 544 X 672 pixels. Other arrays producing very high apparent temperatures in excess of 700 K have also been fabricated. Arrays have been fabricated for projecting low background scenes achieved through cryogenic operation. All arrays are designed to project IR radiation over the full MWIR and LWIR spectral bands. Individual arrays and their emission properties will be described. Array properties at different substrate temperatures will be described. Advances in packaging of these different array types will also be discussed.
An addressable mosaic array of resistively heated microbridges offers the potential to project accurate dynamic infrared (IR) imagery. The main purpose of this imagery is to be used in the evaluation of IR instruments from seekers to FLIRs. With the growing development of lower cost uncooled IR imagers, scene projectors also offer the potential for dynamic testing of these new instruments. In past years we have described developments in a variety of IR projectors systems designed for different purposes. In this paper we will describe recent developments in these technologies aimed at improving or understanding temporal and radiative performance.
An addressable mosaic array of resistively heated microbridges offers much flexibility for infrared scene simulations. In the Wide Band Infrared Scene Projector program, Honeywell has demonstrated high yield arrays up to size 512 X 512 capable of room temperature operation for a 2 band infrared projection system being designed and built by Contraves Inc. for the Wright Laboratory Kinetic Kill Vehicle Hardware In-the-Loop Simulator facility at Eglin Air Force Base, FL. The arrays contain two different pixel designs, one pixel designed for kHz frame rates and high radiance achieved at a power level of 2.5 mWatts/pixel and the other pixel designed for more moderate 100 Hz frame rates at lower radiance and at maximum power levels of 0.7 mWatts/pixels. Tests on arrays and pixels have demonstrated dynamic ranges up to 850:1, radiance rise times on the order of 2 mseconds, and broadband pixel emissivities in the range of 70%. Arrays have been fabricated with less than 0.1% pixel outages and no row or column defects. These arrays are mounted in a specialized vacuum assembly containing an IR window, vacuum package, cooling block, and pump out manifold.
A mosaic array of resistively heated microbridges offers flexibility for infra red scene simulations. The array may operate without flicker and display high-intensity dynamic scenes over a wide bandwidth. Honeywell completed fabrication of a 512 X 512 resistor array with 3.5 mils pitch for AEDC's 7V and 10V test chambers. The emitter has a broad bandwidth covering from 2 micrometers to 26 micrometers . The array operates at 20 K to simulate low radiation backgrounds in space. Up to 16,000 pixels may be turned on to simulate targets and target clusters. Each emitter element may heat up to 550 K with 1 kelvin resolution. The maximum power dissipation per pixel is 830 (mu) W for a pixel heated up to 550 K. The maximum power required is 13.2 watts for 16,000 pixels. This low power capability is derived from Honeywell's silicon nitride microbridge structure. Each emitter has approximately 85% fill factor and an average emissivity of 70% over the 2 - 26 micrometers bandwidth. Defect count in the array is less than 1% with one column out. The array may be addressed at 30 frames per second.
Honeywell and MRC have been developing a range of thermal scene projector arrays through the Wright Laboratory Armament Directorate's cryovacuum resistive infrared scene projector (CRISP) program and the Defense Nuclear Agency's nuclear optical dynamic display system (NODDS) program. The resistive emitters are fabricated on silicon nitride structures on pitches as small as 2 mils. These structures have low thermal mass, low thermal conductance, and high fill factor. Monolithic address and pixel storage electronics provide flicker-free operation of large arrays at high frame rates. The emitters have demonstrated > 600 K blackbody temperatures, high radiance, and > 10<SUP>3</SUP> dynamic range at very low power when operated at 40 K temperatures to achieve low background. This paper describes the performance of a CRISP 512 X 512 array consisting of 3.5 mil pixels and a high-speed 128 X 128 NODDS array consisting of ultra-low-power emitters.
Honeywell Inc. and Mission Research Corporation (MRC) are jointly developing micro resistive heater array displays for projecting dynamic background scenes and targets in the short-wavelength infrared (SWIR) to long-wavelength infrared (LWIR) wavebands. There are two joint government contracts supporting this work: the Nuclear Optical Dynamic Display (NODDS) program under DNA contract DNA001-92-C-0041, which is developing a 512 X 512 array of 50- by 50-micrometers display pixels, and the Cryovacuum Resistor Infrared Scene Projector (CRISP) program for the USAF Wright Laboratory at Eglin AFB, which is developing a 512 X 512 array of 87.5- by 87.5-micrometers pixels. The requirements on the two programs are somewhat different due to their different missions. While the NODDS program is developing an array that can be used to create dynamic nuclear clutter scenes, the CRISP arrays are being designed for simulating multiple independently moving targets; and while the frame rate on the NODDS arrays requires an array capable of 1-kHz frame rates, the CRISP arrays will be operated at 30 Hz.
A number of techniques are under development for creating dynamic IR scenes for testing IR imaging systems. Comparison of these techniques may be misleading if appropriate performance parameters are not used. One straightforward method is the thermal emission from microemitters fabricated in an array. The small mass leads to good response times if crosstalk between elements and to any substrate can be limited. Silicon micromachining can create good performance in arrays of this type because of the excellent thermal isolation of the elements
Recent technological advances have made it possible to form arrays of small thin-film-based bolometric pixels integrated onto Si substrates containing both array addressing and readout electronics. These advances have made bolometer technology a potentially low-cost, high-sensitivity, high-yield staring detector technology for the near future. In this paper, the basic performance aspects of an IR microbolometer are described. The design of a high-performance pixel and the performance measurements on some initial devices are presented. The potential performance of two-dimensional arrays is discussed.