【作者】 施嫚嫚；

【导师】 黄梅珍；

【作者基本信息】 上海交通大学 ， 光学工程， 2011， 硕士

【摘要】 近红外光谱分析法(Near Infrared Spectroscopy, NIRS)因其分析测试操作简单快速,无损伤采样等特点,在农业、医药业、食品安全检测、化工等领域得到了广泛应用,仪器的小型化及智能化也受到了越来越多的关注。本文首先介绍了近红外光谱仪器的发展概况及其基本的仪器原理与结构框架,针对目前光栅扫描型近红外光谱仪器普遍存在杂散光较大和扫描速度较慢的问题,提出了一种基于Cary理论和Czerny-Turner光路结构并采用谐波电机直接驱动光栅的小型快速近红外分光光度计的设计方法,并对其进行了光学软件仿真,设计了相关电路,最后对样机做了初步的性能测试。本文的工作主要包括以下几个方面:本文将Cary理论运用到近红外分光光度计的光路设计中来,减小了光学系统中多次反射及衍射产生的杂散光,并使用光学软件Tracepro对本设计的近红外分光光学系统进行了仿真和分析,仿真结果表明在改进之后的结构中系统杂散光得到了明显的抑制;本文改进了传统的电机传动正弦丝杆再驱动光栅的波长扫描结构,采用谐波电机直接驱动光栅转动的方式,提高了光谱测量速度,减小了仪器的体积,研究建立了电机转角与扫描波长的关系,分析测量了波长的准确性和重复性;另外,为了确保仪器的性能稳定性,电路设计方面采取了模拟闭环与数字闭环相结合的设计,保证了光源和电源的稳定性,为仪器吸光度的准确性和重复性提供了保障;最后,在近红外光波段对样机的性能进行了测试,并根据近红外分析技术原理以及近红外吸收理论,选用葡萄糖水溶液作为样品,进行了简单的定性分析实验。更多还原

【Abstract】 Near Infrared Spectroscopy has been widely used in agriculture, pharmaceutical industry, food safety testing, chemical and other fields, due to its simple fast operation, reliable analysis, non-destructive, non-invasive sampling characteristics. The smaller and intelligent instrument has also been more and more attention.This article surveyed the near-infrared spectrum instrument’s development and introduced the basic structural framing, also have studied the present small near-infrared spectrum instrument’s principle of work and the application domain. In view of the serious stray light in this kind of instrument and the problem of scanning velocity, a small rapid scanning type near-infrared spectrometer (NIR) based on improved Czerny-Turner optical structure with its simulation and test results is presented. To reduce the stray light caused by multiple diffractions and multiple reflections, the optical structure is arranged and optimized by the Cary principle, the simulation and analyze result using optical software Tracepro are also presented in this paper. On the order hand, in order to increase the scanning speed, a harmonic motor is used to drive the grating directly instead of the traditional structure with a screw driver between the motor and the grating. Finally some basic test results of the near infrared spectrometer are presented.This paper innovatively presents Cary theory used in the design of rays path and optics software Tracepro that can be used to simulate and analysis the light-splitting optical system. The experiments result shows that the improvement structure has obviously suppressed the system stray light by reducing the second diffraction and excrescent stray light which reflects many times.This paper also improves the structure by changing traditional sinusoidal motor driving screw between motor and the scanning grating with using a harmonic motor directly to drive diffraction grating. The volume of the structure is reduced and the spectrum scanning speed is raised. The relationship between rotation of diffraction grating and the scanning wavelength is determined, and a signal detector is enough to detect the signal and process the data.In order to guarantee the stability of the instrument’s performance, the circuit design has adopted the analogy and the digital closed loops in the design, which had guaranteed the photo and power source’s stability. It is very important for the instrument wavelength accuracy and repeatability, as well as the instrument’s absorbance accuracy and repeatability.Finally, the prototype’s performance has carried on the test in near infrared light wavelength band. According to the principle of near-infrared technique as well as the near-infrared absorption theory, the transparent glucose solution is selected to take the sample experiments, it has carried on the simple qualitative analysis as well as the different density solutions opposite experiment.更多还原