设计了一种具有40°视场角的手持式免散瞳眼底照相机,可用来拍摄视网膜图像。相机光学系统由照明系统和成像系统组成,其中照明系统设有可见照明光源和红外对焦光源,采用红外光源对焦可以不用药物对眼睛进行散瞳处理。照明光源采用独特的环形LED,将环形LED光源成像于人眼的瞳孔之上,避免照射到角膜上发生反射作用。在成像系统中设置调焦镜,具备±15D的屈光度补偿功能。成像光学系统的点列图均方根值小于2.8 μm,场曲小于0.2 mm,畸变小于0.6%,在70 lp/mm处各视场处的调制传递函数均高于0.4。使用Zemax光学设计软件的成像模拟功能,在光学系统的像面上清晰地再现了原图。该相机可以应用于眼科医学行业,为疾病的预防和康复服务。

A portable non-mydriatic fundus camera with 40° field of view is designed, and it can be used to capture retinal images. The optical system of this camera consists of lighting system and imaging system, in which the lighting system is equipped with visible light source and infrared focusing source. The use of infrared light source focusing can avoid the use of drugs on eye mydriatic treatment. The light source uses a unique circular LED and it is imaged on the human eye pupil to avoid reflection effect as it falls on the cornea. Focusing lens is placed in the imaging system, which has ±15D diopter compensation function. In imaging system, the root mean square of spot diagrams is less than 2.8 μm, the field curvature is less than 0.2 mm, the distortion is less than 0.6%, and the modulation transfer function values are higher than 0.4 at 70 lp/mm in all fields. The original image is clearly reproduced on the image plane by using Zemax software for imaging simulation. This camera can be used for the prevention and rehabilitation of disease in ophthalmic medical industry.