ResearchPast Projects
SPP 1337 - Aktive Mikrooptik - Teilprojekt: Elektromagnetische Ansteuerung von Mikrooptiken: Adaptive Systeme auf der Basis ferrofluidischer Aktoren

SPP 1337 – Active Microoptics – Subproject: Electromagnetic Triggering of Microoptics: Adaptive Systems Based on Ferrofluid Actuators

Year:  2011
Date:  29-11-11
Funding:  German Research Foundation
Duration:  2008-2011
Is Finished:  yes

The subproject "Electromagnetic Control of Microoptics: Adaptive systems based on ferrofluidic actuators" is part of the priority program 1337 "Active Microoptics" of the German Research Foundation (DFG). Within the scope of this project, the Institute for Microproduction Technology (IMPT) develops and manufactures thin film components for a ferrofluidic microactuator. By energizing a microcoil array, an electromagnetic field is generated that displaces a ferrofluid in a microchannel of PMMA. The movement of the ferrofluidic liquid column causes a displacement of an optical liquid in the microchannel and leads to the formation of a liquid lens at the end of the channel. Depending on the position of the ferrofluid in the channel, the radius of curvature of the lens and thus its focal length should be adjustable. Integrated hard magnets are also provided to hold the ferrofluid and thus the lens in a position without external energy supply (see Fig. 1).

The microcoil array is part of a stator system, which also consists of a magnetic flux guide made of NiFe45/55, assembly marks for system integration and embedding the structures from SU-8™ as well as contact pads for controlling the microcoil array.

Finite element method (FEM) analyses to simulate the generated magnetic field and temperature were successfully performed to model the microcoil array. The design for the photolithography masks was derived from the simulation results. A process sequence was set up for the production of the microactuator and the thin-film processes were optimized. Production of the first systems has been completed (see Fig. 2). Based on the experiences from the first production run, an optimized design is created.

After the production of the microactuators, the system integration takes place. Two microactuators form a sandwich structure with the microchannel structure in the middle.