| The problem of food safety is not only a significant livelihood issue endangeringpeople’s health directly, but also an important social issue to the national economicdevelopment and political stability. The advanced analytical instrument is helpful toresist the serious reality of food safety in our country. Because Fourier TransformSpectrometer (FTS) has large radiation flux, high accuracy and good precision, socombining it with micro-optical-electro-mechanical system (MOEMS) to develop aportable spectroscopy detection system has important research value and socialsignificance.The commercial programmable MOEMS micro-mirror which has digital opticalswitch characteristics makes the miniaturization of instruments feasible. Combining itwith plane mirror and tilting mirror, the equal thickness interference can be obtainedbased on Michelson interferometer. Based on it, this system can detect the spectrumwith a single detector, which abandons the moving mirror part in the traditional FTS.Therefore, the novel FTS based on MOEMS micro-mirror proposed in this paper hashigh-performance of small volume, low cost and high reliability.Firstly, the principle of FTS based on MOEMS micro-mirror is introduced. Andthe MOEMS micro-mirror diffraction analysis in near-infrared by scalar diffractiontheory is completed. The analysis results show that most of diffraction light intensitygathers in the zero-order reverse diffraction and the optical system of signal acquisitionis just applied to collect it. Then the collimator and convergent parts in spectroscopydetection system are designed and optimized by Zemax optical software based ontheory analysis. According to the function, the spectroscopy detection system hardwarepart based on FPGA is divided into several modules, which include signal acquisition,MOEMS micro-mirror driving, data storage, USB communication in details. Moreover,the system power supply circuit is designed.The optic and hardware test experiments are made to ensure that the design iscorrect. In the collimation test, the uniform of light intensity is more than95.3%and theconsistency of spot size is more than98%. The system power supply ripple test resultsshow that the max ripple voltage is less than30mV and the ripple factor is less than2%.The debugging of the hardware circuits based on FPGA is accomplished and it turns outto be able to perform expected function. The spectroscopy detection is carried out on the wavelength band of900nm~1700nm. The results indicate that the resolution of thesystem is better than10nm and the stability of system is less than0.4%. |
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