光学学报, 2014, 34 (8): 0823004, 网络出版: 2014-07-15
高速TDI CCD空间相机焦平面设计与实验
Design and Experiment of Focal Plane for High Speed TDI CCD Space Camera
光学器件 遥感 空间相机 高速TDI CCD 交错拼接 焦平面组件 optical devices remote sensing space camera high speed TDI CCD interleaving focal plane assembly
摘要
时间延迟积分(TDI)CCD焦平面组件是空间相机的重要组成部分,主要完成光电转换,输出模拟CCD视频信号,是影响相机成像质量高低的关键部件之一。现有TDI CCD的像素数量有限,不能满足大视场、宽覆盖的要求,需要对CCD进行拼接。从结构和热控两方面入手针对空间相机高速TDI CCD焦平面组件开展了设计工作,分析了影响拼接精度的因素,针对相机恶劣的发射条件和苛刻的在轨工作温度,设计了特殊的拼接结构来保证TDI CCD拼接精度。开展了动力学环境实验和热真空环境实验来验证拼接结构的可靠性,结果表明:焦平面组件完全能够克服相机力学环境,保证TDI CCD的拼接精度;在热真空实验中,TDI CCD器件在1.5 min工作时间内最高温度为30 ℃,CCD能够正常工作。动力学环境实验和热真空实验后对TDI CCD的拼接精度进行了检测,得到TDI CCD拼接的直线性精度3.5 μm,搭接精度4 μm,两行 TDI CCD平行精度3.5 μm,4片TDI CCD共面精度5 μm,拼接精度完全满足光学设计要求。外场成像实验得到的清晰图像进一步验证了焦平面组件设计的合理性和可行性,实现了TDI CCD的高精度拼接。
Abstract
Time delay integration (TDI) CCD focal plane assembly is one of the most important components for a space camera, which mainly fulfill photoelectric conversion and output video signal of analog CCD. Due to the hard condition resulted from the transportation and launch of a space camera, it is difficult to keep a TDI CCD with high interleaving precision. Therefore, in this work, we design a TDI CCD focal plane assembly with a good performance based on the optimization both on structural control and thermal control. According to the analysis of the factors that affect the interleaving precision of a TDI CCD focal plane assembly and the maximal error of three axes theoretically, we design an especial structure for a TDI CCD focal plane assembly to keep the high interleaving precision of a TDI CCD which can fit the hard condition for the transportation and launch of a camera and the harsh on-orbit operating temperature. The effectiveness of the modified TDI CCD focal plane assembly is supported by the results obtained from dynamic test and thermal vacuum test. For the dynamic test, the response result shows that the assembly can conquer the interference of dynamic environment and keep a high interleaving precision of TDI CCD. For the thermal vacuum test, thermal balance test indicates that the highest temperature of TDI CCD is 30 ℃ in 1.5 min, which can work properly. The interleaving precision of focal plane is done after the dynamic environment and thermal vacuum tests. The linearity error of the TDI CCD is 3.5 μm, the interleaving error is 4 μm, the parallelism error between two lines of the TDI CCD is 3.5 μm, and the coplanar error of 4 TDI CCD is 5 μm. These results satisfy the optical design very well. Therefore, the aforementioned course proves that this design is feasible and precise, and it can achieve a high interleaving precision for a TDI CCD.
贾学志, 张雷, 安源, 金光. 高速TDI CCD空间相机焦平面设计与实验[J]. 光学学报, 2014, 34(8): 0823004. Jia Xuezhi, Zhang Lei, An Yuan, Jin Guang. Design and Experiment of Focal Plane for High Speed TDI CCD Space Camera[J]. Acta Optica Sinica, 2014, 34(8): 0823004.