1. MEMS for Adaptive Optics
Adaptable-Mirror Section
Movable Mirror Elements
Scale ~10s to 100s mm
Array of Elevating Mirrors
Mirror Substrate
Scale ~ mm to cm
Current-Driver
Electronics
Solder-Bump
Electrical Connections
Conceptual slide
Specs:
20um vertical actuation
mirror diameter < 200um
-3dB roll off frequency > 20Hz
CMOS compatible process desired
tilable

2. How Can We Elevate the Mirror Elements?
Magnetic Actuation
Solenoidal structures
Electrostatic Actuation
Vertical comb-drives
Thermal Actuation
Thermal-bimorph structures
Our initial design approach

3. Berkeley Bimorph Process
Single-mask process
Low-stress nitride (SixNy) and aluminum bimorph
Other processes under consideration
Hidden actuators
Electrostatic actuators
Bonded mirrors
Current path
Mirror
Mirror
Die photo - actuated, released mirrors

4. Conclusions
Bimorph actuator is small and can be fabricated under the mirror
Fill factor > 98%
Bimorph actuators can be tiled in an arrays to actuate large numbers of mirrors
Bimorph actuator provides large tip deflection (h = 10 mm)
Models show frequency requirements are met (f>1 kHz)
Bimorph actuators have been fabricated
Testing is underway