1/4节距自聚焦透镜与石英传象光纤组成的纤维窥镜的设计

Design of the Endscope Composed of 1/4 Pitch GRIN Lens and Silica Image Optical Fiber

1/4节距自聚焦透镜是石英传象光纤的理想物镜,它们可组成质量好、体积小、结构紧凑、易于安装的光纤窥镜系统.本文分析了1/4节距自聚焦透镜在石英传象光纤成象系统中的成象原理,讨论了系统的视场、景深以及透镜与光纤的数值孔径的匹配等问题,得出了相应的数学公式,可供系统设计参考,以获得光纤传输的最佳效果。

The 1/4 Pitch GRIN lens is an ideal object lens of the silica image optical fiber; they can form an endscope together with the advantages of its good quality, its small and compact size, its simple installation and its low cost. In the paper, the imaging principle of the 1/4 pitch GRIN lens in the endscope is analyzed; and the look-out angle, the length of field and the numerical aperture matching between the microlen and the fiber are discussed. The mathematical formulas for the systematic design are obtained. The look-out angle, the depth of field and the numerical aperture ought to be considered at the same time in the process of designing the endscope; and the numerical aperture matching should be first satisfied in order to gain the best transmission.