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介绍了一种测量液晶盒厚度的新型光学方法--反射光谱拟合法.理论上,液晶盒的反射光谱呈正弦曲线,且曲线取极值时对应入射光波长大小值取决于所用液晶盒的厚度.反之亦然,当得知液晶空盒的反射光谱时,可以根据曲线取极值时入射光波长的值来获得待测液晶盒的厚度.软件用来搜索与实验测试数据相互吻合的液晶盒厚度.该技术以白光作为液晶盒的前端光源,且白光入射角为0°.结果表明,该方法测量范围5～30 μm,测量重复误差0.1 μm以下.实验中,光纤光谱仪用来测试反射光谱,并通过USB接口将其传输到计算机.该方法的优点是它可以在0.1 s内测试液晶盒表面任意点处的厚度,有较强的使用价值.

Reflective spectrum information of a vacant LCD cell was extracted to measure the gap of the vacant cell. Theoretically, the reflective spectrum of the cell shows the sinus form,the position of maximal peak depends on thickness of the gap. Vice versa, when the spectrum of the vacant cell had been measured, the peak point could be fitted by theoretical predicted peak of the correct gap. The software was made to search the "correct gap", which should be optimally fit the peak of measured spectrum, and the result of the theoretical search was adapted as the result of measurement. Tungsten lamp was used as light source, and the angle o fincidence light is 0°. Analysis shows that the measurable gap can cover from 5 μm to 30 μm and the experiments show that the repeating error is less than 0.01 μm. In the experiment,first the fiber spectrograph was used to test the reflected spectral, then it communicated the reflected spectral to the computer by the USB interface, at last the computer searched for the thickness of the gap by fitting the reflected spectral. The advantage of this method is that it can measure the thickness of any position of the cell in less than 0.1 s, which has high use value.