针对60 mm×45 mm尺寸碘化铯荧光屏，设计一个用于牙科诊断的X射线数字化成像光学系统。选用有效尺寸4.8 mm ×3.6 mm的CCD作为接受器件，光学系统结构型式为复杂化双高斯型，相对孔径和全视场角分别达到F/0.9和35°，有效焦距9 mm。全视场MTF 在空间频率56 lp/mm时高于0.75，全视场畸变为1.8%, 边缘视场照度与中心视场照度之百分比达到80%。从设计结果可以看出，整个系统的像差得到了较好的校正，满足数字化X射线成像系统的使用要求。

An optical system of digital X-ray radiography based on CsI scintillation screen with 60 mm×45 mm dimension for dental diagnosis was designed. A CCD with a 4.8 mm×3.6 mm image surface was selected. The lens system had a complicated double-Gauss configuration. The F# and full field of view were up to F/0.9 and 35° respectively, the focal length was 9mm. The results showed that the modulation transformation function of full field of view was greater than 0. 75 at the spatial frequency of 56 lp/mm, the distortion of full field of view was 1.8%, and the relative illumination reached 80%.The aberrations of the whole system were corrected, which met the requirements for the digital X-ray radiography system.