透射式透明薄膜厚度的在线测量
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摘要
为满足工业半透明薄膜厚度在线检测的实际需求,提出了一种基于透射式光密度计量法的全场在线测量方法.该方法利用相机采集放置薄膜前后的图像灰度,将其作为入射与出射能量并计算其光密度,再通过比尔-朗伯定律建立光密度与厚度之间的关系.为减小测量误差,采用标准光密度标定板对系统进行标定,对计算的理论光密度进行偏移校正.该系统结构简单,单次测量面积可达100 mm×75 mm;以聚四氟乙烯薄膜为例进行验证,测量的平均误差为5.7%,标准偏差为6.66%,为薄膜厚度全场在线检测提供了新的可行性.
In order to satisfy the industrial requirements for online thickness inspection of semi-transparent thin film,a method based on optical transmission density was proposed. The optical density could be calculated with the output and input radiation captured by camera,which were grayscale values received with and without thin-film respectively. Then the relationship between density value and thickness was constructed according to the Beer-Lambert law. To reduce measurement error,the density was calibrated with the standard calibration sheet and the density drift of calculated value was corrected. The system had a simple configuration and measured an area of 100 mm×75 mm each time. PTFE film was adopted to demonstrate the feasibility of the method. The analysis results showed that the average error of the densitometer was 5.7% with a standard deviation of 6.66%. The method can be applied to full-field online thickness measurement of thin film.
In order to satisfy the industrial requirements for online thickness inspection of semi-transparent thin film,a method based on optical transmission density was proposed. The optical density could be calculated with the output and input radiation captured by camera,which were grayscale values received with and without thin-film respectively. Then the relationship between density value and thickness was constructed according to the Beer-Lambert law. To reduce measurement error,the density was calibrated with the standard calibration sheet and the density drift of calculated value was corrected. The system had a simple configuration and measured an area of 100 mm×75 mm each time. PTFE film was adopted to demonstrate the feasibility of the method. The analysis results showed that the average error of the densitometer was 5.7% with a standard deviation of 6.66%. The method can be applied to full-field online thickness measurement of thin film.
引文
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[11]刘俊武. LED式固态薄膜厚度在线测量系统研究[D].哈尔滨:哈尔滨工业大学,2011.LIU J W. Research on LED solid state film thickness online measurement system[D]. Harbin:Harbin Institute of Technology,2011.
[12]王晓宇.薄膜厚度在线测量系统的研制[D].哈尔滨:哈尔滨工业大学,2012.WANG X Y. Development of measurement system of thinfilm thickness on-line[D]. Harbin:Harbin Institute of Technology,2012.
[13] LARENA A,PINTO G,MILLAN F. Using the LambertBeer law for thickness evaluation of photoconductor coating for recording holograms[J]. Applied Surface Science,1995,84(4):407-411.
[14] BRASUNAS J C,CUSHMAN G M,LAKEW J. Thickness measurement,in the measurement,instrumentation and sensor handbook[M]. New York:CRC Press,1999.
[15] MULLIKIN J C,van VLIET L J,NETTEN H,et al. Methods for CCD camera characterisation[C]∥Proceeding of SPIE conference on Image Acquisition and scientific Imaging Systems.[s.l]:SPIE,1994:73-84.
[2]秦玉伟.基于光学相干层析成像技术的薄膜厚度测量[J].激光技术,2012,36(5):662-664.QIN Y W. Film thickness measurement based on optical coherence tomography[J]. Laser Technology,2012,36(5):662-664.
[3] MARSZALEK K,WOLSKA N,JAGLARZ J. Angle resolved scattering combined with optical profilometry as tools in thin film and surface survey[J]. Acta Physica Polpnica A,2015,128(1):81-86.
[4] SIDERVO V,MLADENOVA D,YORDANOV R,et al.Film thickness measurement by optical profilometer Microprof FRT[J]. Bulgarian Chemical Communications,2013(45):194-197.
[5] GUO T,WU J H,NI L F,et al. Initial estimation of thin film thickness measurement based on white light spectral interferometry[J]. The Solid Films,2016,612:267-273.
[6]肖青,王兴龙,傅谦,等.一种用于厚度在线检测的光学装置[J].光学学报,2015,35(2):293-299.XIAO Q,WANG X L,FU Q,et al. An optical device for on-line measurement of thickness[J]. Acta Opyica Sinica,2015,35(2):293-299.
[7]宋敏,郑亚茹,卢永军,等.一种可实现薄膜厚度在线监测的方法[J].光学技术,2007,33(3):447-449.SONG M,ZHENG Y R,LU Y J,et al. An optical method of online measurement for thickness of thin film[J]. Optical Technique,2007,33(3):447-449.
[8] DU F X,DONG X F,WANG Y. Development of thickness measuring instrument based on reflecting infrared[J].Journal of University of Science and Technology of Suzhou(Engineering and Technology),2006,19(3):81-83.
[9]徐源,黄金强,崔灿,等.利用红外光谱仪快速测量塑料薄膜厚度[J].物理实验,2012,32(5):31-33.XU Y,HUANG J Q,CUI C,et al. Thickness of plastic films measured by FT-IR technology[J]. Physics Experimentation,2012,32(5):31-33.
[10]梁伟.非接触式在线光密度仪[D].郑州:郑州大学,2010.LIANG W. Non-contact and online optical density sensor[D]. Zhengzhou:Zhengzhou University,2010.
[11]刘俊武. LED式固态薄膜厚度在线测量系统研究[D].哈尔滨:哈尔滨工业大学,2011.LIU J W. Research on LED solid state film thickness online measurement system[D]. Harbin:Harbin Institute of Technology,2011.
[12]王晓宇.薄膜厚度在线测量系统的研制[D].哈尔滨:哈尔滨工业大学,2012.WANG X Y. Development of measurement system of thinfilm thickness on-line[D]. Harbin:Harbin Institute of Technology,2012.
[13] LARENA A,PINTO G,MILLAN F. Using the LambertBeer law for thickness evaluation of photoconductor coating for recording holograms[J]. Applied Surface Science,1995,84(4):407-411.
[14] BRASUNAS J C,CUSHMAN G M,LAKEW J. Thickness measurement,in the measurement,instrumentation and sensor handbook[M]. New York:CRC Press,1999.
[15] MULLIKIN J C,van VLIET L J,NETTEN H,et al. Methods for CCD camera characterisation[C]∥Proceeding of SPIE conference on Image Acquisition and scientific Imaging Systems.[s.l]:SPIE,1994:73-84.