A novel technology is presented for arrays of vertical flaps as optically modulating elements which are actuated
electrostatically to horizontal position at low voltages of 30-50V. One application is a reflective display exhibiting
a contrast ratio of 1:95. We will also show a) shutters for transmissive devices in an array configuration and
b) switchable gratings. A large variety of flap geometries are fabricated such as flat reflective, grating, lens or
grid shape. Poly-Si refill of thin high aspect-ratio trenches followed of dry etching of the surrounding material is
used to fabricate the flaps suspended by torsion beams.
A new kind of MEMS reflective display is being developed having high contrast and reflectivity, better than on printed
paper. The system is based on novel vertical flaps, which can be electrostatically turned by 90° to horizontal position.
After fabrication, the poly-silicon flaps are vertical to the wafer surface and on the top suspended by torsion beams. In
this state the pixel is black, incoming ambient light passes by the flaps and is absorbed by an underlying absorptive layer.
When the flaps are turned to horizontal position light is reflected back and the pixel gets white. A self-aligning four
masks bulk microfabrication process is employed, which uses poly-silicon filling of high aspect-ratio cavities. Parylene
was also employed as flap material. Thanks to auto stress-compensation the flaps are not deformed due to intrinsic
stresses. Low actuation voltages down to 20V can be achieved.
We show the first results of a linear 100-micromirror array capable of modulating the phase and amplitude of the spectral
components of femtosecond lasers. Using MEMS-based reflective systems has the advantage of utilizing coatings tailored
to the laser wavelength range. The innovative features of our device include a novel rotational, vertical comb-drive actuator
and an X-shaped, laterally reinforced spring that prevents lateral snap-in while providing flexibility in the two degrees of
freedom of each mirror, namely piston and tilt. The packaging utilizes high-density fine-pitch wire-bonding for on-chip
and chip-to-PCB connectivity. For the first deployment, UV-shaped pulses will be produced to coherently control the
dynamics of biomolecules.