Designing analysis and tools to measure the longevity of infrared led scene projectors

Abstract

Infrared (IR) detectors are becoming an ever more sophisticated and important tool in today’s research laboratories. In order to test and calibrate these IR detectors, an infrared source or infrared scene projector (IRSP) is required. The first IRSP using infrared LEDs (IRLEDs), called the SLEDS projector, was developed by our team in 2014, and has logged several hundred hours of operation. IRLED projectors promise to deliver faster framerate and higher resolution than what is currently possible with today’s IRSPs. Since the creation of the first SLEDS projector, newer versions of the system have been developed including a Two-Color SLEDS Array (TCSA), which contains two infrared LEDs per pixel instead of one. ☐ IRSPs output better imagery at cryogenic temperatures and are often cooled using liquid nitrogen while in operation. Because the TCSA is a new type of IRSP, it is important to test the longevity of the IRLEDs in relation to the stress on the array from repeatedly being cooled to cryogenic temperatures. This thesis analyzes the maximum radiance output of the first Two-Color SLEDS Array, TCSA1, across cryogenic cycles. After examining various metrics of maximum radiance output over more than 80 cycles, no significant degradation was observed in the majority of the functioning IRLEDs. The analysis and tools used to examine TCSA1 can be directly applied to other current IRSPs and modified to account for the needs of future IRSP systems.