使用梯度折射率液晶微透镜阵列的光场成像

光场成像可以获取场景的三维信息。通过在主透镜和图像传感器之间插入一个微透镜阵列, 不仅可以记录光线的辐射度, 还记录了光线入射的方向。提出了使用梯度折射率液晶微透镜阵列进行光场成像的方法。该阵列基于向列相液晶材料, 利用其各向异性和双折射的特点, 通过紫外光刻技术和湿法刻蚀技术制作, 具有圆孔阵列图案。在该阵列的上下电极之间加载一个交流电压信号后, 每个微透镜可以有效会聚入射光, 搭建了测试系统来测试该阵列的聚焦特性和焦距。将该阵列与一个主透镜和一片图像传感器耦合得到一个光场成像相机, 并使用该相机采集了图像。

Abstract

Light field imaging is an imaging method which can acquire the three-dimensional information of the scene. By inserting a microlens array between the main lens and the imaging sensor, it records both the radiance and the direction of the incident rays. Light field imaging using a gradient index liquid crystal microlens array (LCMLA) was proposed. Based on nematic liquid crystal materials for their anisotropy and birefringence, the LCMLA with a pattern of a circular-hole array was fabricated using ultraviolet lithography and wet etching. When an alternate voltage signal was applied between the two electrodes of the LCMLA, each microlens can converge incident rays effectively. An experimental system was set up to verify its focusing performance and measure its focal length. Then the LCMLA was assembled with a main lens and an imaging sensor to construct a light field imaging camera. Raw images were taken using the camera based on LCMLA.

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雷宇, 佟庆, 张新宇. 使用梯度折射率液晶微透镜阵列的光场成像[J]. 红外与激光工程, 2017, 46(2): 0220002. Lei Yu, Tong Qing, Zhang Xinyu. Light field imaging with a gradient index liquid crystal microlens array[J]. Infrared and Laser Engineering, 2017, 46(2): 0220002.

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