Spatial alignment and functional manipulation of droplet-based systems

至少在过去的几十年里，液体控制成为微系统技术的一个重要课题。传统的液体驱动，如膜或微型涡轮机，已被基于静电场效应的非机械概念所取代。在这种情况下，液体的运动到目前为止仅限于一维（电毛细管）或二维方法（EWOD，数字微流体）。基于我们在第一个资助期对液滴操作的研究，静电光流体将扩展到液滴的受控全三维运动。此外，电极的空间排列将允许液滴形状控制，从而改变折射。得到了一种可自由配置的畸变变焦式光流元件光学阵列。该光学阵列由多孔板上堆叠的多电极阵列组成，允许液滴通过具有稳定静止位置的3D框架移动，可与液滴的高机架存储相媲美。关键的挑战是使液滴在单层内和两层之间的所有空间方向上独立运动。由于2.5 d技术不允许完全对称的3D排列，因此需要充分安排合作静电致动器。堆叠层的协调相互作用将提供机会，以不同的静电场形成单个液滴。这为研究先进的光学应用提供了机会，例如需要交叉光轴，同时同步驱动多个流体透镜或流体透镜的动态重塑。由于所提出的三维致动器内电场的复杂形状及其复杂的几何形状，这意味着表面能的计算具有挑战性，因此不可能对所提出的系统进行经典的白盒建模。因此，我们将开发一种新的识别算法，该算法迭代地揭示系统拓扑并识别系统参数。结果将是一个平坦的状态空间模型，因此使用基于平坦度的闭环控制方法将是可能的。该研究将使需要多个高度可调透镜的流体透镜在应用中得到应用。通过构建高机架存储型光流体微致动器的演示器，并研究腔网内液滴的耦合效应和特殊特性，创建了光流体测试平台。利用本项目开发的先进控制技术将提高光流体应用的性能，并将其应用领域扩展到动态任务，如运动跟踪或激光雷达。

Control of liquids became an important topic in microsystems technology at least over the last decades. Conventional liquid actuation e.g., by membranes or micro-turbines has been replaced by non-mechanical concepts based on electrostatic field effects. In this context, the movement of liquids has so far been limited to a 1D-(electrocapillarity) or a 2D-approach (EWOD, digital microfluidics). Based on our studies on droplet manipulation from the first funding period, electrostatic optofluidics will be extended to a controlled full 3D motion of droplets. Furthermore, the spatial arrangement of electrodes will allow a droplet shape control and therefore a change in the refraction. An optical array with optofluidic elements like an anamorphotic zoom is obtained that can be configured freely. This optical array consists of stacked multi-electrode arrays on perforated plates, that allows to move droplets through a 3D framework with stable rest positions, comparable to a high rack storage for droplets. The key challenge is to enable an independent movement of droplets in all spatial directions within a single layer and between two layers. This requires a sufficient arrangement of cooperating electrostatic actuators as the 2.5D-technology does not allow fully symmetric 3D arrangements. The coordinated interaction of stacked layers will offer the opportunity to shape individual droplets by differential electrostatic fields. This offers the opportunity to investigate advanced optical applications, which require for example crossed optical axes, synchronous actuation of multiple fluid lenses at the same time or a dynamic reshaping of fluid lenses. Because of the sophisticated shape of the electrical field within the proposed 3D actuator and its complex geometry, which implies a challenging calculation of surface energy, a classical white box modeling is not possible for the proposed system. Therefore, we will develop a novel identification algorithm, which iteratively uncovers the system topology and identifies the system parameters. The result will be a flat state space model and thus the use of flatness based closed loop control approach will be possible. This research will enable the use of fluid lenses in application, which need multiple highly adjustable lenses. By building up a demonstrator of a high rack storage like optofluidic micro actuator and investigating coupling effects and special features of droplets within a mesh of cavities a testing platform for optofluidics is created. Using advanced control technologies developed within this project will enhance the performance within optofluidic applications and will expand their application area to dynamic task like motion tracking or LIDAR.