System for driving 2-D infrared emitter arrays at cryogenic temperatures

Abstract

Large IR detector arrays, particularly ones intended for military and aerospace applications, are often difficult and expensive to directly test. These detectors require an IR projector for scene simulation. Current methods for testing such sensors rely heavily on expensive field test programs and/or utilize lower performance thermal emission-based IR scene projectors. Recently there has been increased interest and development of seminconductor-based infrared (IR) LED-based emitter array devices (e.g. SLEDS), due to their ability to produce higher apparent temperatures, lower background temperatures, and much faster rise and fall times than thermal emission techniques. These devices flip-chip a large CMOS driver chip onto a two-dimensional array of IR emitter devices typically fabricated on a GaSb substrate. Several testing sessions showed the unique functionality and capabilities in several important areas such as: apparent temperature exceeding 1000 Kelvin, rise and fall time of 3–4 microseconds, and low apparent background temperatures. Unfortunately, SLEDS arrays require the removal of kW-level heat fluxes while being maintained at liquid-nitrogen temperatures. Although multiple project for construction of these IR emitter arrays are underway, currently there appears to be no cooling system available to operate these arrays at the performance level that they are capable of achieving.