折射率(refractive index,RI ) 是眼镜镜片的重要参数,影响眼镜镜片的厚度和舒适程度。RI的精确测量,能够为屈光不正患者选择合适的镜片提供指导。本文提出了一种利用频域光学相干层析(optical coherence tomography,OCT) 系统测量成型眼镜镜片RI的方法。利用放置镜片前后两次干涉的图样和简单的数据分析计算即可得到待测成型镜片的RI。介绍了使用这种方法的工作原理以及装置,首先对一个K9玻璃材质透镜RI进行测量,结果为1.507(1 310 nm),相对误差不超过2%,以此验证了该方法的合理性、可行性。随后利用此方法对一只成型眼镜镜片进行了测量,得到其RI为1.554(1 310 nm),测量结果的扩展不确定度为0.008 6(k=2)。该方法属于非接触测量,不会对成型镜片造成损坏,操作简便,测量相对误差较低,可基本满足对于成型眼镜镜片RI的测定精度要求。

Refractive index (RI) is an important parameter of spectacle lens,which affects the thickness and comfort of spectacle lens.The accurate measurement of RI provides guidance for patients with ametropia to choose appropriate spectacle lens.This paper presents a method for measuring the RI of formed spectacle lens by frequency domain optical coherence tomography (OCT) system.Based on the optical path matching method, the RI can be obtained by the pattern of two interferences before and after placing the spectacle lens,combined with simple data analysis and calculation. This paper also introduces the working principle and device of this method.Firstly,the RI of a K9 concave lens is measured,and the result is 1.507 at 1 310 nm.The relative error is less than 2%,which verifies the rationality and feasibility of this method. Then,the RI of spectacle lens is measured by this method,and its RI is 1.554 at 1 310 nm.The expanded uncertainty of the measurement result is calculated as 0.008 6 (k=2).This method is a non-contact measurement,which will not damage the lens.It also has the advantages of simple operation and low relative error.It can meet the requirements for the accuracy of spectacle lens RI.

国家重点研发计划 (2021YFC2401401)和南开大学 2022 年自制实验教学仪器设备项目(22NKZZYQ08)资助项目