Many applications of MOEMS microscanners rely on accurate position feedback. For MOEMS devices which do not
have intrinsic on-chip feedback, position information can be provided with optical methods, most simply by using a
reflection from the backside of a MOEMS scanner. By measuring the intensity distribution of the reflected beam across a
quadrant diode, one can precisely detect the mirror’s deflection angles. Previously, we have presented a position sensing
device, applicable to arbitrary trajectories, which is based on the measurement of the position of the reflected laser beam
with a quadrant diode. In this work, we present a novel setup, which comprises the optical position feedback
functionality integrated into the device package itself. The new device’s System-in-Package (SiP) design is based on a
flip-folded 2.5D PCB layout and fully assembled as small as 9.2×7×4 mm³ in total. The device consists of four layers,
which supply the MOEMS mirror, a spacer to provide the required optical path length, the quadrant photo-diode and a
laser diode to serve as the light source. In addition to describing the mechanical setup of the novel device, we will
present first experimental results and optical simulation studies. Accurate position feedback is the basis for closed-loop
control of the MOEMS devices, which is crucial for some applications as image projection for example. Position
feedback and the possibility of closed-loop control will significantly improve the performance of these devices.
One of the important challenges for widespread application of MOEMS devices is to provide a modular interface for easy handling and accurate driving of the MOEMS elements, in order to enable seamless integration in larger spectroscopic system solutions. In this contribution we present in much detail the optical design of MOEMS driver modules comprising optical position sensing together with driver electronics, which can actively control different electrostatically driven MOEMS. Furthermore we will present concepts for compact spectroscopic devices, based on different MOEMS scanner modules with lD and 2D optical elements.
One key challenge in the field of microfluidics and lab-on-a-chip experiments for biological or chemical applications is the remote manipulation of fluids, droplets and particles. These can be volume elements of reactants, particles coated with markers, cells or many others. Light-driven microfluidics is one way of accomplishing this challenge. In our work, we manipulated micrometre sized polystyrene beads in a microfluidic environment by inducing thermal flows. Therefore, the beads were held statically in an unstructured microfluidic chamber, containing a dyed watery solution. Inside this chamber, the beads were moved along arbitrary trajectories on a micrometre scale. The experiments were performed, using a MOEMS (micro-opto-electro-mechanical-systems)-based laser scanner with a variable focal length. This scanner system is integrated in a compact device, which is flexibly applicable to various microscope setups. The device utilizes a novel approach for varying the focal length, using an electrically tunable lens. A quasi statically driven MOEMS mirror is used for beam steering.
The combination of a tunable lens and a dual axis micromirror makes the device very compact and robust and is
capable of positioning the laser focus at any arbitrary location within a three dimensional working space. Hence, the developed device constitutes a valuable extension to manually executed microfluidic lab-on-chip experiments.