【作者】 邱超；

【导师】 孙晓刚；

【作者基本信息】 哈尔滨工业大学 ， 仪器科学与技术， 2014， 博士

【摘要】 聚合物薄膜是一种重要的化学材料。随着石油化学工业和聚合物加工工业的发展，聚合物薄膜的生产、应用也获得了很大的发展，并在农业、包装、化工、国防和人们生活等方面扮演了越来越重要的角色。在聚合物薄膜众多工业性能要求当中，厚度是衡量其质量的主要技术指标。聚合物薄膜厚度不仅涉及到生产工厂的成本，还会影响其拉伸强度、阻隔性等实际应用效果。因此，聚合物薄膜厚度在线检测一直是人们关心的重要问题。本文采用宽波段光吸收法对聚合物薄膜厚度进行在线检测。针对目前商业化薄膜厚度在线检测装置采用的双波长对比法存在的双单色光测量位置偏差、通用性差等问题，研制一种抗环境干扰能力强、无需配置滤光片、具有长期工作可靠性的薄膜厚度在线检测系统是本文研究的关键问题。在宽波段内应用朗伯定律，并基于宽波段光吸收法建立一种薄膜厚度测量模型是本文研究的又一个重要问题。此外，针对工业聚合物薄膜生产线不停机持续生产的实际情况，根据宽波段光源长期工作时波段光强的变化来补偿光谱强度的波动也是本文研究的一个重要问题。针对上述问题，开展本文的研究工作。本文的主要研究内容如下：（1）根据宽波段光在透过薄膜后的光辐射衰减情况，提出了基于宽波段光吸收法的薄膜厚度在线测量方法。分析了光辐射在介质中传播时的指数衰减规律及物质自发辐射谱和吸收谱的洛伦兹线型。讨论了当一定频率区间内的光辐射在物质中传播时，物质光学厚度光谱分布与光源光谱强度分布的带宽比及两者中心频率偏移率对光学厚度测量的影响。研究了宽波段光吸收法测量物质厚度时，抗系统误差及随机误差的能力。在提出波段朗伯定律概念的基础上，提出了宽波段薄膜厚度测量模型。该模型不需对薄膜的特征吸收带进行分析，适用于在较宽波段内均有光吸收特性的薄膜，且具有很强的抗光谱透过率测量随机误差能力。对厚度为100m左右的薄膜测量时，仿真误差绝对值在0.4m以内；实验误差绝对值在0.8m以内。（2）针对工业现场聚合物薄膜生产的特殊应用要求，研制了宽波段薄膜厚度在线检测系统。根据宽波段薄膜厚度测量模型，建立了光功率与薄膜厚度的函数关系。根据离散函数的特性，采用了基于数值分析的薄膜厚度反演方法。该系统采用宽波段热辐射光源及基于热电堆探测器的光功率计，根据宽波段光吸收法对工业生产线中的聚合物薄膜进行在线扫描检测。分析了光源与探测器相对位置变化对探测器接收光辐射的影响。采用扫描全程的小标样动态标定方法对扫描架导轨进行了标定。标定完成后，测量100m以内薄膜时，导轨扫描引入的最大误差范围小于0.7m。（3）针对工业聚合物薄膜生产线长期连续工作的情况，提出了基于波段光强的宽波段光源光谱辐射强度波动补偿方法。该方法通过研究黑体光谱辐射出射度和全辐射出射度的依赖关系，建立了光谱辐射出射度与波段辐射出射度的函数关系式。该方法应用于在线检测系统时，不需要额外增加硬件设备，只需测量光源的波段光强变化即可补偿光源光谱辐射强度的波动，解决了在线检测系统长期工作时光源波动对检测结果的影响问题。在黑体全辐射出射度变化1倍时，绝大多数数据点的补偿结果相对误差绝对值在1%以内。不同电源输入功率下宽波段光源光谱强度拟合相对误差绝对值在1.5%以内。（4）对检测系统进行了实验研究及不确定度分析。采用在线获取方法得到了薄膜样品并使用轮廓仪测量了其厚度。使用傅里叶光谱仪测量了薄膜样品的光谱透过率和光源相对光谱强度。获取了光功率与薄膜厚度的关系曲线，得出检测系统在测量100m以内薄膜时测量分辨率为0.4m。使用不同厚度的薄膜标样，对系统检测误差进行了测试实验。系统30个厚度输出值与标准厚度最大偏差在1.5m以内，其中每个厚度输出值为5次测量的平均值。分析了系统测量不确定度，得到了系统在50m~150m的检测范围内，单次测量结果的扩展不确定度(k2)在3.0m以内；5次测量均值的扩展不确定度()在1.7m以内。更多还原

【Abstract】 Polymer film is an important kind of chemical material. With the development ofpetrochemical industry and polymer processing industry, polymer film production andapplication also obtain a great development. Polymer film plays an increasinglyimportant role in agriculture, packaging, chemicals, defense and people’s life. In manyindustrial performance requirements, the thickness of the polymer film is a maintechnical indicator for measuring quality. The polymer film thickness is not only relatedto the production cost, but also affects the actual application effect such as the tensilestrength, barrier properties. Therefore, polymer film thickness on-line measurement hasalways been a main concerned problem.In this dissertation, broadband optical absorption method is proposed for polymerfilm thickness on-line measurement. At present, the dual-wavelength contrast method isused in commercialize film thickness on-line measurement device, while it has theproblems of double monochromatic measurement position deviation and poor versatility.For these problems, to develop an on-line film thickness measurement system with ananti-environmental interference ability, long-term reliability, and without having toconfigure filters is a key issue of this dissertation. Applying Lambert law in broadbandand building a film thickness measurement model based on broadband opticalabsorption method is another important issue of this dissertation. In addition, for theindustrial polymer film production line actual situation of non-stop continuousproduction, compensating illuminant spectral intensity fluctuations, according to thechange of broadband intensity during the long working time is also an important issueof this dissertation. In response to these problems, carry out research work of thisdissertation. The main research contents are as follows:(1) According to the optical radiation attenuation of broadband light after passingthrough the film, the film thickness on-line measurement method based on broadbandoptical absorption is proposed. Exponential decay laws of optical radiation pass inmedium and Lorentzian lineshape of material spontaneous radiation spectrum andabsorption spectrum are analyzed. When a certain frequency range of light radiationpropagates in material, the influences of the bandwidth ratio of the material opticalthickness spectral distribution and the illuminant spectral intensity distribution and theircenter frequency drift rate on the material optical thickness measurement are discussed.The abilities of resistance to the systematic error and random error are analyzed, whenusing broadband optical absorption method to measure material thickness. Thebroadband film thickness measurement method is proposed, after the concept of band Lambert law was proposed. This model does not need to analyze the characteristicabsorption band of the film, and is suitable for the film with a wide band lightabsorption characteristics, and has a strong resistance of random error for spectraltransmittance measurement. The absolute value of simulation error is less than0.4mand the absolute value of experimental error is less than0.8m when the film thicknessis about100m.(2) For special application requirments of polymer film production in industrial site,a broadband film thickness on-line measurement system is developed. A functionbetween optical power and film thickness is built according to the broadband filmthickness measurement model. With the characteristics of discrete function, a filmthickness inversion method based on numerical analysis is adopted. A broadbandthermal radiation illuminant and a optical power meter based on thermopile detector areused in the system. The broadband optical absorption method is used for polymer filmon-line scan measurement. The influence of relative position change of illuminant anddetector to the light radiation received by the detector is analyzed. The scanning frameguide rail is calibrated with the dynamic calibration method using small-sized standardsamples to scan the whole range. After the calibration, maximum error range due toguide rail scanning is less than0.7m when measuring film at the thickness of100mor less.(3) For the long-term continuous industrial polymer film production line case,broadband illuminant spectral radiation intensity fluctuation compensation methodbased on band intensity change is proposed. The functional relationship betweenspectral radiant exitance and band radiant exitance is built by studying the dependencerelationship between spectral radiant exitance and whole radiant exitance of blackbody.When this method is applied to on-line measurement system, no additional hardwaredevice is needed. Illuminant spectral radiation intensity fluctuation can be compensatedjust by measuring the illuminant band intensity change. This method solve the problemof the influence of illuminant fluctuation to measurement results. The vast majority ofdata points compensation results are in a relative error of less than1%, when theblackbody whole radiant exitance vary double. The fitting relative error of broadbandilluminant spectral intensity is less than1.5%at different power input.(4) The experiment research and uncertainty analysis of the measurement system iscarried out. The film samples are obtained by using on-line method and theirthicknesses are measured by contourgraph. The spectral transmittances of the filmsamples and the illuminant relative spectral intensity are measured by Fourierspectrometer. The relationship curve of optical power and film thickness is obtained,and the measurement resolution of the system is0.4m for measuring film at the thickness of less than100m. Use film standards with different thicknesses to test thesystem measurement error. The maximum deviation between30thickness outputs andthe standard thickness are less than1.5m; each thickness output value is the average of5measurements. The uncertainty of the measurement system is analyzed. In themeasurement range of50m to100m, a single measurement expanded uncertainty(k2) is3.0m and the mean of5measurements expanded uncertainty () is lessthan1.7m.更多还原