P10 - Analog Driver for Synchronized Resonant and Quasistatic MOEMS Mirrors

SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
Proceedings OPTO 2011
OP - Poster Session
M. Lenzhofer, A. Frank, A. Kenda, A. Tortschanoff - Carinthian Tech Research AG, Villach (Austria), T. Sandner - Fraunhofer Institute for Photonic Microsystems, Dresden (Germany)
155 - 160


We have developed and implemented a closed loop driving concept in order to synchronize electrostatically driven MOEMS components, which have attracted increasing interest due to their possible applications in MOEMS based pico-projection devices, bar-code scanners, spectrometers, endoscopes, 3D distance scanners and others.

Synchronized driving of several scanner mirrors is a major challenge, due to the spread in the properties like resonance frequency and response curves of the micromechanical components.

Two different drivers were developed in order to deal with two different electrostatically driven MOEMS types, namely resonant scanners and quasistatic deflection mirrors. While resonant scanner mirrors with in plane electrodes are driven at resonance, quasistatic mirrors feature out-of plane electrodes and typically are driven below the resonance frequency and thus can follow nearly arbitrary trajectories. The mirror frequencies can be in the tens of kHz range and our final goal is to reliably synchronize up to 8 mirrors.

For the resonant mirrors, which are driven at a defined frequency and amplitude, we basically use a phase locked loop circuit in combination with a rectifier and a slow control stage for the amplitude. A microcontroller based implementation is realized, where a digital reference signal is supplied to define frequency and phase of the oscillation and independently a DC-signal for the target amplitude is provided.

The quasistatic mirrors are driven with a PID closed loop control, which has to be adapted to the mirror characteristics. In this case an arbitrary target trajectory is provided in the form of an analog signal in order to specify the mirror motion. Beside the closed loop circuit the key electronic elements are the multichannel high voltage driver and a high voltage DC/DC converter to provide driving voltages up to 150 V.

A detailed description and comparison of the two electronic designs will be presented at the conference together with a first characterization of our drivers.