Designing Optically & Utilization of Thermopile Chip with Resonant Cavity Absorber Structure as IR Absorber

Abstract

This paper presents a novel thermopile chip in which the resonant cavity structure was fully utilized as an absorber by an optical design. The resonant cavity absorber structure was designed using Al as anthe bottom reflective metal layer, air as the intermediate dielectric layer, and SiO2/TiN/Si3N4 sandwich layers as the top absorption layer, while the bottom reflective metal (Al) was deposited on the cold junctions of the thermopile. The simulation and calculation results show that the thermopile chip with resonant cavity absorber structure not only has great infrared absorption in the wide infrared absorption range but also can effectively prevent the cold junctions from absorbing infrared radiation and inhibit the rise of temperature. As a result, the temperature difference between the hot junctions and the cold junctions is increased, and the responsivity of the thermopile chip is further improved. Moreover, the duty cycle of the thermopile chip is greatly improved due to the double-layer suspension structure. Compared with the traditional thermopile chip structure, the sizes of the thermopile chip with the resonant cavity absorber structure can be further reduced while maintaining responsivity and specific detectivity.

Performance Investigation of Power Inverter Components Submersed in Subcooled Liquid Nitrogen for Electric Aircraft

“…Power modules with high current capabilities are preferred to achieve highpower delivery. Figure 4 shows a three-level active neutral point clamped (ANPC) inverter [13][14][15][16]. ANPC inverters have several features over conventional two-level voltage source inverters, such as lower semiconductor devices, which can be utilized because of the reduced conduction loss.…”

“…Power modules with high current capabilities are preferred to achieve high-power delivery. Figure 4 shows a three-level active neutral point clamped (ANPC) inverter [13][14][15][16].…”

“…Cooling a power electronics converter to low temperatures (e.g., using cryogenic cooling; in our research, cooling was achieved by submersion in subcooled liquid nitrogen), can significantly improve the efficiency and power density of a power conversion system [13]. Such configuration may require special tools to measure the temperature variation optically using thermopiles [14]. For instance, a high-efficiency cryogenic (under 77 K) boost chopper was designed and experimentally evaluated in [15].…”

A Highly Accurate Method for Measuring Response Time of MEMS Thermopiles

“…Herein, the response time is the time required by the device to detect the object and reach the stable state, which reflects the response speed of the device to external excitation [ 18 , 19 ]. In the past few decades, previous research has been mainly focused on shortening the response time of the device by optimizing thermopile structures [ 20 , 21 , 22 , 23 , 24 ]. However, accurate measurement methods for this parameter have not been well developed.…”