New high resolution Thermopile Arrays for IR Imaging, person detection and consumer applications

Abstract:
Infrared arrays found their way into widespread applications in various industries. Due to increasing resolutions and decreasing costs, the growth rates for Infrared (IR) imaging sensors and cameras are assumed to continue having double-digit annual growth rates for the coming decade. Apart from that, the pandemic situation in 2020 and 2021 gave this technology a special boost with annual growth rates near 100 % compared to 2019 and before. The simple technology of shutterless thermopile arrays could benefit in many large-scale “elevated body temperature” scanners, whereas thermal bolometers of VGA and higher resolution allowed measuring several persons in parallel respective the tear duct. Unlike other array technologies, thermopile arrays allow to build true shutterless radiometric IR cameras or modules. The reason is, that thermopile arrays are DC sensitive devices and do not need to be biased. Thermopile arrays with pixel numbers from 8 x 8, 16 x 16, 32 x 32 resp. 32 x 24 and 80 x 64 were introduced to mass production for various consumer applications with pixel sizes of about 90 µm [3]. Array formats above 80 x 64 pixel or with smaller pixel sizes around 50 µm were so far clearly the domain of micro bolometers or other technologies. In this paper, Heimann Sensor introduces first thermopile arrays with 60 and 45 µm pixel sizes allowing to extend the application range into higher density thermal imaging and lower cost security and surveillance application. All necessary signal conditioning and readout electronics including SPI interface are monolithically integrated on the sensor chip.