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 Csl scintillation screen with 60 mmX45 mm dimension for dental diagnosis was designed. A CCD with a 4. 8 mmX3. 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.
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