The thermal-mechanical performance of the uncooled infrared optical-readout bi-material FPA

Abstract

and other uncooled micro-mechanical detectors, which is largely due to the simple fabrication and potential for high yield and low cost. So the authorities such as University of california in Berkley (Varesi et al. 1997;Mao et al. 1999;Zhao and Mao 2002), Oak ridge national laboratory (Senesac et al. 2003;Grbovic et al. 2008); turkey (Ferhanoglu et al. 2007), Boston University (huang et al. 2008;Kwon et al. 2009) and Shanghai Institute of Microsysytem and Information Technology, caS (Yan et al. 2009) had concentrated on the research for about 7-10 years and also shown a lot of inspiring results. During 2007-2013, we had also presented a novel Ir-FPa and successfully developed the model prototype of the infrared camera (Dong et al. 2007;Jiao et al. 2007; Yan-mei et al. 2011). Which improved the absorption in the wavelength range of 8-14 μm significantly. however, there are still several difficult points to be further investigated. Such as: the mechanical uniformity of the pixels, the response sensitivity, the vibration frequency of the FPa, and the thermal dependency between the neighboring pixels. In this paper, we mainly discuss about the thermal-mechanical performance of the substrate-free optical-readout bi-material FPa. Figure 1 demonstrates the schematic diagram of the Ir imaging system based on the optical-readout bi-material cantilever FPa. The Ir radiation is collected directly to one side of the FPa, which causes the substrate-free bi-material cantilevers deform after absorbing thermal heat, and the deformation of the cantilevers drive the vertical shift of the reflector. The visible optical path is on the opposite direction of the FPa, the visible light emitted by the leD is collimated by the lens and then reflected by the shifted reflectors, then via a 4f Fourier transform system, the frequency spectrum is filtered by the optical filter on the spectrum plane. So the light fluxes passing through the filter changes Abstract This paper analyzed the thermal-mechanical performance of the optical-readout bi-material infrared focal array plane (Ir-FPa), mainly on the pixel non-uniformity phenomenon. Based on the Fraunhöfer diffraction theory, the model of the initial angle inconformity among the pixels due to the processing bias was presented, the result shows that the initial angle tolerance of pixels must be kept within 0.358° for the 49.5 × 49.5 μm 2 pixel. The intensity of the image corresponding to different reflect angles of pixels was tested using the 360° horizontal rotary micro displacement stage driven by stepped motor. and the result agrees with the theoretical calculation. Furthermore, the thermal-mechanic sensitivity S T and dynamic range of the object temperature (blackbody) was also computed, which affords new reference for the research and manufacture of the optical read-out Ir-FPa process.