采用电流镜积分读出电路的X射线图像传感器  

X-ray image sensor with a current mirror integration readout circuit

作　　者：张文普[1,2] 袁祥辉[1] 潘银松[1] 吕果林[1] 黄友恕[1] 

机构地区：[1]重庆大学光电技术及系统教育部重点实验室 [2]解放军重庆通信学院,重庆400035

出　　处：《光电工程》2005年第2期71-74,共4页Opto-Electronic Engineering

基　　金：国家自然科学基金资助项目(60077025)

摘　　要：研制采用电流镜积分高性能读出电路的 X 射线图像传感器(CMI-X-IS),传感器像元由采用CMOS 工艺的光电二极管实现,利用电流镜将产生的光电流变成镜像并放大到积分电容中,经相关双采样电路抑制噪声后,由 CMOS 移位寄存器和多路开关电路输出视频信号。对 CMI-X-IS 要求的时序关系进行了分析。设计了 CMI-X-IS 的应用电路,并将其应用于一个实验系统中,得到了不同密度、不同尺寸材料的视频信号波形和清晰的目标物 X 射线图像。实验表明,CMI-X-IS具有较小的非均匀性(NU≤3.532%)、较低的暗噪声(Vn≤0.45mV)、较大的单位面积响应度(Ro=57.87×105V/Lx.S.cm2)、较高的输出电压(可达 5V)和较宽的动态范围(Dr ≥77dB),可以应用到 X 射线实时成像检测领域。An X-ray image sensor using a current mirror integration (CMI-X-IS) readout circuit is developed. The elements of the sensor consist of photodiodes made with CMOS technology. The current generated by optical excitation is mirrored and magnified in an integrated capacitor. After noise suppression by correlated double sampling, video signals are exported out by CMOS shift register and Multiplexer and Output Stages. Analysis of time sequence for CMI-X-IS required is carried out and an application circuit of CMI-X-IS is designed in an experimental system. In this way the video signal waveforms of material with different density and size, and clear X-ray object image are obtained. Experiments show that CMI-X-IS has small non-uniformity (NU [less-than or equal to] 3.532%), low noise of dark output voltage (Vn [less-than or equal to] 0.45 mV), large unit area responsibility (R0 = 57.87 × l05V/Lx.S.cm2), high output voltage (V0 = 5 V) and wide dynamic range (Dr greater than or equal 77 dB). CMI-X-IS can be used for X-ray real-time radioscopy inspection.

关 键 词：X射线传感器 图像传感器 电流镜积分读出电路 应用电路 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]