柔性大面积高密度液体微镜阵列实时/域调焦及预应力释放压印成型工艺

Compared to the conventional solid-state microlens, because of its advantages in dramatic wider visual angle and easier to achieve tunable focus by real-time/location control, high-density liquid microlens array on elastic substrate is considered as one of the most promising microlens systems, and may have a giant application in various fields. However, the focus offset, image distortion, film crack and function failure of the conventional metal electrode may happen during the geometric deformation of liquid microlens array on flexible substrate. In this project, a novel fabrication method is proposed to prepare high density liquid microlens array on planar/curved substrates. The process is that, by extending and flattening the flexible planar/curved substrate with pre-tensile force, micro-cavities are patterned by imprinting on the UV curable polymer film which is based on the elastic substrate, and then graphene electrodes with excellent electrical/mechanical properties are prepared by ink-jet tools, finally the pre-tension is released and the elastic substrate is recovered to its original planar/curved shape. So, in this project, we will focus on the designing of device structures, development of new fabrication principles, optimization of fabrication processes and characterization of functional properties of the liquid microlens array on planar/curved flexible substrate. The concrete research contents include, mapping the microstructure evolving between the imprinting mold and patterning on flexible substrate during the pre-tensile extending and the releasing process, exploring the function failure mechanism of the graphene electrode (the tensile, bendable strength of atomic film) under the substrate stress and strain, and developing rapid, low-cost fabrication process of high density liquid microlens array on flexible planar/curved substrate.

柔性基高密度液体微镜阵列相比固态微镜具有显著的视角优势，以及硬质微镜难以实现的实时/域调焦功能，被认为是具有巨大应用前景的一种新型微镜结构。但柔性基液体微镜阵列通过简单几何变形扩大视角必然造成焦点偏移、成像失真，用于调焦的传统金属电极也可能由于形变而导致开裂、失效。本课题提出以预应力拉伸/展平柔性平面/异形面，在UV固化聚合物薄膜上压印成型微腔结构，以喷印方式形成具有优异电/机械特性的石墨烯透明驱动电极，再释放预应力恢复弹性基体平面/异形面形状结构，最终成型高密度平面或大视角异形面微镜阵列。为此，从器件结构、制造原理、工艺方法和功能特征等方面，拟研究预应力释放前后模具与弹性基上微腔结构的映射关系；研究柔性材料释放保型微压印成型工艺；探索应力应变与超优导电性能薄膜(石墨烯)电极的失效机制，发挥原子层厚度薄膜的抗拉、抗弯机械特性；发展快速、低成本、大面积柔性高密度液体微镜阵列制造工艺的新途径。

柔性基高密度液体微镜阵列具有实时/域调焦功能和显著的视角优势，可作为一种新型微镜结构，广泛应用在空间遥感、环境监测、疾病诊断等领域。本项目针对柔性基高密度液体微镜阵列容易焦点偏移、成像失真，电极容易形变失效等问题，建立了一种快速、低成本、实用化的大面积柔性液体微镜阵列制造工艺，探索高密度液体微镜阵列制造工艺的新途径。本项目采用以预应力拉伸/展平柔性平面/异形面，在 UV 固化聚合物薄膜上压印成型的微腔结构，实现精确聚焦和精确成像，采用以喷印方式形成具有优异电/机械特性的石墨烯透明驱动电极，再释放预应力恢复弹性基体平面/异形面的形状结构，实现非失效变形，最终成型高密度平面或大视角异形微镜阵列。因此本项目探索了应力应变与超优导电性能薄膜(石墨烯)电极的失效机制，研究了预应力释放前后模具与弹性基上微腔结构的映射关系，发挥了原子层厚度薄膜的抗拉、抗弯机械特性，制造了柔性材料释放保型异形微镜阵列。