双波段光纤内窥镜物镜设计

摘要

In order to meet the needs for circadian reconnaissance and target detection ,a visible and near-infrared dual-waveband endoscope with image fiber bundles was designed .After ana-lyzing basic principles ,the telecentric optical system in image space with retrofocus type was selected as its initial structure .Through the optimization with ZEMAX ,the results of wavelength ,focal length ,F number ,field of view (FOV) and optical length were respectively 0 .486 μm~0 .656 μm/0 .7 μm~1 .1 μm ,1 .21 mm/1 .22 mm ,4 ,80° and 8 .45 mm/8 .47 mm .As the filament diameter of image fiber bundles was 16 μm ,and it was arrayed as square ,the optical system needed to be evaluated at 31 lp/mm .T he results show the requirement of telecentric path in image space is satified completely .It has uniform illumination at image plane on axis and off-axis .The modulation transfer function (M T F) value of this system is greater than 0 .81 at the spatial fre-quency of 31 lp/mm in visible part ,which is 0 .80 in near-infrared part .The design of this dual spectral endoscope makes the function of traditional endoscope realized ,and also enhances the range of detection and amounts of information ,w hich can achieve the measurement and obser-vation in day and night .%为适应昼夜侦查、探测目标的需要，设计了可见与近红外双波段光纤内窥镜物镜。在分析其基本原理的基础上，采用反远距形式的像方远心光路结构作为初始结构，通过Zemax 软件进行优化设计，给出了一个工作波长0．486μm～0．656μm/0．7μm～1．1μm，焦距1．21mm/1．22mm，F数为4，视场角为80°，光学长度为8．45mm/8．47mm的设计实例。传像束单丝直径16μm ，并按正方形排列，据此要求在31 lp/mm处评价像质。设计结果表明，系统满足像方远心光路要求，轴上和轴外像面照度均匀，该镜头可见光部分在31 lp/mm空间截止频率处M T F值超过0．81，近红外部分在31 lp/mm空间截止频率处M T F值超过0．80。该双波段内窥镜的设计在实现已有内窥镜功能的同时，又提升了探测范围和信息量，能够实现全天候的检测与侦查。