为准确测量光学玻璃的折射率,提高光学系统成像质量,介绍了现有光学玻璃折射率测试方法和国内外发展现状,提出了一种利用测量棱镜3个顶角所对应的3个最小偏向角的折射率测量新方法。该方法充分利用了互补法或三像法定位的优势,提高了折射率的测量精度,其特点是测量精度随被测光学玻璃的折射率增大而提高。推导出了计算公式,并对精度做了理论分析。结果表明:同传统最小偏向角法相比,测量精度提高2倍以上,可满足高精度测量光学玻璃折射率的要求。

In order to measure accurately the refractive index of optical glass to improve the imaging quality of optical systems,several measuring methods of refractive index for optical glass were analyzed and both foreign and domestic development situations for optical glass measurement were introduced.A new method to calculate refractive index by measuring the three least deflection angles of three vertex angles of a prism was presented.Proposed new method made full use of the orientation dominance of complementary method or three-image method improve the accuracy of refractive index measurement,and it was characteriszed by the accuracy improvement of refractive index measurement with refractive index increasing.The formula of new method was deduced,the measurement accuracy was analyzed in the theory.Result indicates that measurement accuracy has improved more than twice as compare with that of traditional least deflection angle method,which can meet the requirement of high accuracy measurement of refractive index.