80×32 SOI diode-based uncooled IRFPAs for thermal detectors

We describe uncooled infrared focal plane arrays (IRFPAs), which consist of pn junction diodes fabricated on a silicon-on-insulator (SOI) layer using a complementary metal oxide semiconductor (CMOS) process. Based on this technique, we released the Mitsubishi Electric Diode Infrared sensor (MelDIR) into the thermal detector market in 2019. This sensor is an 80×32 IRFPA with a 25 μm pixel pitch, utilizing a chip-scale vacuum-packaging process. To reduce the sensor cost, we developed a common differential circuit that switches the column pixel line, and achieved a significant reduction in chip area. In order to use a low-cost lens in the sensor module, we also developed an aberration correction method that improves the temperature measurement accuracy. Furthermore, we evaluated the effectiveness of a shutter-less method based simply on the thermal behavior of the SOI diode. These techniques allow enhanced performance of the MelDIR.