Uncooled infrared thermal imaging sensor using vacuum-evaporated europium phosphor

Abstract

This paper reports an uncooled infrared (IR) thermal imaging sensor using europium phosphor, Eu(TTA)3, as a temperature-sensitive medium. An Eu(TTA)3 thin film was evaporated and deposited on a thermally isolated microstructure made of SU-8. The temperature dependency of luminescence from Eu(TTA)3 was used to convert the IR radiation power into visible-light intensity, which can be captured and digitized by a charge-coupled device (CCD) camera. The temperature coefficient of luminescence from the evaporated Eu(TTA)3 was −2.1 ± 0.4% K−1. Thermal images of a heater at 75−370 °C were acquired via a Ge lens. The minimum detectable temperature, noise-equivalent temperature difference (NETD), and thermal response time were measured as 75 °C, 2.66 K at 370 °C, and 0.2 s, respectively.