基于红外TFT-LCD的非机械式微扫描技术研究

Non-Mechanical Micro-scan Technology Based on Infrared TFT-LCD

提出了一种旨在提高非制冷红外焦平面空间分辨性能的非机械式微扫描方法,该方法利用在3～5μm和8～14μm中远红外波段有良好的光开关性能的红外液晶材料,制作成像素间距和规模与非制冷红外焦平面阵列相当的TFT-LCD矩阵。按行、列选择红外TFT-LCD矩阵的开与关,得到与二级机械式微扫描一致的同一场景的4幅微位移图像,通过插值重建获得采样频率提高到2倍的场景微扫描图像。分析了该方法的实现机理,给出了实际可行的微扫描系统方案,并采用该方法的思想对辐条状图案进行了微扫描仿真。与常规的机械式微扫描技术相比,该非机械式微扫描方法具有重量轻、机械复杂度低、稳定可靠、重复精度高的显著优点。

To improve spatial resolution performance of un-cooled IR-FPAs, a non-mechanical micro-scan method was developed that allows infrared TFT-LCD matrix to be used as micro-scan device. Infrared liquid crystal was used to produce infrared TFT-LCD matrix for its perfect light switching performance in 3-5μm and 8-14μm spectrum. The pixel space and scale of infrared TFT-LCD matrix were equivalent to that of infrared focal plane array. Infrared TFT-LCD matrix was switched off and on by rows and columns, and 4 frames of micro-shifted images from the same scene were acquired as in normal mechanical micro-scan. Interpolation technique was used to rebuild images free of aliasing out to twice the Nyquist frequency determined by IR-FPA. The method was theoretically analyzed, a practical micro-scan system scheme was presented, and simulation for two-dimensional case was presented. Compared with conventional mechanical micro-scan, this non-mechanical micro-scan method was lighter weight, less mechanical complexity, greater reliability, and higher repetition accuracy.