Yin Jiajia, Mao Danbo, Fan Bin
Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China.
Polymers (Basel). 2021 Mar 24;13(7):1001. doi: 10.3390/polym13071001.
Polyimide diffractive membrane lens can be used in space optical telescope to reduce the size and mass of an imaging system. However, traditional commercial aromatic polyimide membrane is hard to meet the challenging requirements of dimensional stability and optical homogeneity for optical use. Based on molecular structure design and the optimization of fabrication process, the prepared copolyamide-imide membrane achieved the desired performance of membrane as an optical material. It showed a very low coefficient of thermal expansion (CTE), which is 0.95 ppm/°C over a temperature range of -150-100 °C and relatively low coefficient of moisture expansion (CME), which is only 13.30 ppm/% RH (0~90% RH). For the optical use, the prepared copolyamide-imide membrane (φ200 mm) achieved good thickness uniformity with wave-front error smaller than λ/30 (λ = 632 nm) in RMS (root mean square). Besides, it simultaneously meets the optical, thermal, and mechanical requirements for space telescope use. Copolyamide-imide membranes in this research with good comprehensive performance can be used as large aperture membrane optical system architectures.
聚酰亚胺衍射膜透镜可用于空间光学望远镜，以减小成像系统的尺寸和质量。然而，传统的商用芳香族聚酰亚胺膜难以满足光学应用中对尺寸稳定性和光学均匀性的苛刻要求。基于分子结构设计和制备工艺的优化，所制备的共聚酰胺 - 酰亚胺膜实现了作为光学材料的膜所需性能。它表现出非常低的热膨胀系数（CTE），在 - 150至100°C的温度范围内为0.95 ppm/°C，以及相对较低的湿膨胀系数（CME），仅为13.30 ppm/%RH（0~90%RH）。对于光学应用，所制备的共聚酰胺 - 酰亚胺膜（φ200 mm）实现了良好的厚度均匀性，均方根（RMS）波前误差小于λ/30（λ = 632 nm）。此外，它同时满足空间望远镜使用的光学、热学和机械要求。本研究中具有良好综合性能的共聚酰胺 - 酰亚胺膜可用于大口径膜光学系统架构。
