Robert G. Stockbridge

Recent progress in large dynamic resistor arrays

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.

History of resistor array infrared projectors : hindsight is always 100% operability

Numerous infrared scene projection technologies have been investigated since the 1970s. Notably, from the late 1980s the development of the first resistor array infrared projectors gained leverage from the strong concurrent developments within focal plane array imaging technology, linked by the common need for large integrated circuits comprising a 2-dimensional array of interconnected unit cells. In the resistor array case, it is the unit cell comprising the resistively heated emitter and its dedicated drive circuit that determines the projector response to its associated scene generator commands. In this paper we review the development of resistor array technology from a historical perspective, concentrating on the unit cell developments. We commence by describing the technological innovations that forged the way, sharing along the way stories of the successes and failures, all of which contributed to the steady if somewhat eventful growth of the critical knowledge base that underpins the strength of todays array technology. We conclude with comments on the characteristics and limitations of the technology and on the prospects for future array development.

Large-area infrared microemitter arrays for dynamic scene projection

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.

Innovations in IR projector arrays

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.

512x512 WISP (wideband infrared scene projector) arrays

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.

Characterization and nonuniformity correction of a resistor array infrared scene projector

Ever increasing developments in imaging infrared (IR) seekers that are being designed for Ballistic Missile Defense Office (BMDO) guided interceptor programs have amplified the necessity for robust hardware-in-the-loop (HWIL) testing to reduce program risk. Several candidate HWIL IR projection technologies are under development. This paper addresses the characterization measurements of a 128 X 128 metal-oxide semiconductor field-effect transistor (MOSFET) resistor array scene projector. The measurements include spectral output performance, dynamic range, spectral apparent temperature, uniformity, rise time, fall time, droop percentage, and current consumption. With possibly the exception of hot target simulation, the resistor array has the ability to spatially, spectrally, and temporarily function as the scene projector for a HWIL facility.

512x512 cryovacuum resistor infrared scene projector

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 AEDCs 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 Honeywells 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.

Multispectral scene projection (MSSP) demonstration

The MSSP program is a tri-service development of a capability for test and evaluation of multi-spectral seeker systems. At the conclusion of the project, each service will be equipped with an MSSP system specifically tailored to meet its specific test and facility requirements.

High-performance 512 x 512 scene projector for targets against space backgrounds

Honeywell and MRC have been developing a range of thermal scene projector arrays through the Wright Laboratory Armament Directorates cryovacuum resistive infrared scene projector (CRISP) program and the Defense Nuclear Agencys 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 > 103 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.