Iwai Daisuke, Izawa Hidetoshi, Kashima Kenji, Ueda Tatsuyuki, Sato Kosuke
Osaka University, Graduate School of Engineering Science, Toyonaka, 560-8531, Japan.
Kyoto University, Graduate School of Informatics, Kyoto, 606-8501, Japan.
Sci Rep. 2019 Aug 26;9(1):12365. doi: 10.1038/s41598-019-48900-z.
Electrically tunable lenses (ETL), also known as liquid lenses, can be focused at various distances by changing the electric signal applied on the lens. ETLs require no mechanical structures, and therefore, provide a more compact and inexpensive focus control than conventional computerized translation stages. They have been exploited in a wide range of imaging and display systems and enabled novel applications for the last several years. However, the optical fluid in the ETL is rippled after the actuation, which physically limits the response time and significantly hampers the applicability range. To alleviate this problem, we apply a sparse optimization framework that optimizes the temporal pattern of the electrical signal input to the ETL. In verification experiments, the proposed method accelerated the convergence of the focal length to the target patterns. In particular, it converged the optical power to the target at twice the speed of the simply determined input signal, and increased the quality of the captured image during multi-focal imaging.
电可调透镜（ETL），也称为液体透镜，可通过改变施加在透镜上的电信号在不同距离聚焦。ETL不需要机械结构，因此，与传统的计算机化平移台相比，它提供了更紧凑、更便宜的聚焦控制。在过去几年中，它们已被广泛应用于各种成像和显示系统，并实现了新颖的应用。然而，ETL中的光学流体在驱动后会产生波纹，这在物理上限制了响应时间，并显著阻碍了适用范围。为了缓解这个问题，我们应用了一个稀疏优化框架，该框架优化了输入到ETL的电信号的时间模式。在验证实验中，所提出的方法加速了焦距向目标模式的收敛。特别是，它将光焦度以简单确定的输入信号两倍的速度收敛到目标，并在多焦点成像期间提高了捕获图像的质量。
