手持式眼底相机光学系统设计

Optical System Design of Portable Fundus Camera

提出一种新型眼底成像系统,结构更加简单、紧凑。系统的成像和调焦投影光路共用调焦镜,调焦投影光路完全嵌入到照明光路。调焦投影光路不再专设照明组件,避免了投影目标和调焦镜之间的机械联动结构。并且充分利用了网膜物镜系统的空间。利用LED光源窄带宽的优势,瞄准和拍照过程共用一个电荷耦合器件相机。采用新的光学结构,设计了一款视场30°、工作距离30mm的眼底相机光学系统,眼光焦度补偿范围-10m-1～+5m-1,物方各视场分辨率为45line/mm,畸变小于5%。

A portable fundus camera is designed to make the optical system more simple and compact comparing with the classical system. The photographing system and the focus target projection optical system are using a common focusing lens, so that the focus target projection optical system can be arranged completely in the illumination system. In the focus target projection system a special illumination system is not required any longer, and a focus link mechanism between the projective target and the focusing lens is avoided. Focusing lens fully utillizes the space of the retina object lens system. Taking advantage of narrow bandwidth of light source, observation system and photographing system share the common charge coupled device. A new type of fundus camera is designed with the field of view of 30~, the free working distance of 30 mm. The accommodation ranges between - 10 m-1 and ＋5 m-1. The resolution at the object plane of 45 line/mm across the entire field of view, and the maximum distortion is less than 5 %.