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Proceedings Paper

Novel structure for ultrafast uncooled focal plane array
Author(s): Zhengxi Cheng; Bin Ma; Xuemin Zhang; Houming Zhai; Yongming Shi
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Paper Abstract

A novel structure combining normal uncooled focal plane array (UFPA) microbridge and RF MEMS switch is presented. The MEMS switch is integrated into the microbridge without any modification of the microbridge structure and fabrication process. The upper electrode of the switch is the IR absorbing layer of the microbridge, and the down electrode is the reflecting mirror of the IR resonant chamber on the substrate. With the help of the MEMS switch, the microbridge can be pulled down to the substrate, and be cooled to the substrate temperature T0. Correlated double sampling(CDS) method is used to read out the difference between R(T0) and R(T1), where R(T0) is the value of thermistor on the microbridge when the microbridge is pulled down to the substrate, and cooled to the substrate temperature T0, and R(T1) is the value of thermistor when the microbridge is heated up to T1 by radiation after the microbridge is released from the substrate for a certain short time. The difference between R(T0) and R(T1) is just related to thermistor R itself, and no reference resistor is need. Match between the thermistor and its reference in normal structure, which is the most difficult task in fabrication, is no longer existed. And the signal due to mismatch between the thermistor and the reference resistor, which is very large compared with the signal due to the thermistor change, and which often makes op saturated, also no long exists. In CDS read-out circuit, the difference between R(T0) and R(T1) can be very small, which cannot approximate thermal equilibrium state. So it only needs a very short time for the microbridge to absorb radiation. The simulation results show that this novel structure can work up to 10KHz without any performance decrease, which is 100 times faster than the speed of the normal structure.

Paper Details

Date Published: 22 October 2010
PDF: 6 pages
Proc. SPIE 7658, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology, 76584R (22 October 2010); doi: 10.1117/12.867693
Show Author Affiliations
Zhengxi Cheng, Shanghai Institute of Technical Physics (China)
Bin Ma, Shanghai Institute of technical physics (China)
Xuemin Zhang, Shanghai Institute of Technical Physics (China)
Houming Zhai, Shanghai Institute of Technical Physics (China)
Yongming Shi, Shanghai Institute of Technical Physics (China)


Published in SPIE Proceedings Vol. 7658:
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology
Yadong Jiang; Bernard Kippelen; Junsheng Yu, Editor(s)

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