ksjp, 7/01 MEMS Design & Fab Vertical electrostatic actuation of torsional mirrors A typical 1 axis torsional mirror Torsional spring Electrostatic actuators Flat, reflective mirror

ksjp, 7/01 MEMS Design & Fab Vertical electrostatic actuation: problems Large angle + stability  large gaps Large gaps  small forces  small torque Small torque  flimsy springs Flimsy springs  low resonant frequency!

ksjp, 7/01 MEMS Design & Fab Mirror design Reflective mirror  metallic coating Metallic coating  thermal bimorph Curvature requirement  thick silicon Thick silicon  higher mass  slow mirror

ksjp, 7/01 MEMS Design & Fab 1DOF  2DOF

ksjp, 7/01 MEMS Design & Fab 2DoF Micromirror anchor Back-side etched cavity anchor

ksjp, 7/01 MEMS Design & Fab Challenges with this methodology Low SCS beam/structure must be compliant in z and stiff in x, y Performance is aspect-ratio limited => highSCS beam is too stiff Lateral actuation displaces the mirror laterally Lateral pull x z y

ksjp, 7/01 MEMS Design & Fab Challenges – Lateral displacement Very little rotation due to vertical stiffness of low SCS yank leg Lateral pull dominates actuation

ksjp, 7/01 MEMS Design & Fab Challenges: 2D mechanisms

ksjp, 7/01 MEMS Design & Fab Bond/transfer results Long HF Release of TopSCS handle wafer Target wafer is a regular Si wafer

ksjp, 7/01 MEMS Design & Fab Optical Comm Proof of Concept Receiver 1” lens, std. video CCD PCMCIA Frame grabber Software decoding Laser transmitter –4bps OOK –Laser pointer (Radio Shack)

ksjp, 7/01 MEMS Design & Fab Laser Comm at 5.2 km 14 microW, ~1mrad 8 mW, ~1mrad 3 mW, ~100mrad Received by a CCD video camera with 3” aperture. During daylight, through light rain.

ksjp, 7/01 MEMS Design & Fab Video Semaphore Decoding

ksjp, 7/01 MEMS Design & Fab Smart Dust ’01 Goal

ksjp, 7/01 MEMS Design & Fab CCR Interogator

ksjp, 7/01 MEMS Design & Fab Smart Dust Mini Mote

ksjp, 7/01 MEMS Design & Fab Simulation of CCR reflection Goal: predict impact of diffraction and non-flat, non-perpendicular mirrors Methodology: Divide faces into discrete rectangular elements Perform ray-tracing to determine direction and phase of each ray Sum Fraunhofer diffraction integrals from discrete elements. Author: Victor Hsu (with Joe Kahn, K. Pister, UCB; contact

ksjp, 7/01 MEMS Design & Fab CCR Differential Scattering Cross-section Angle error, 1 side (Courtesy: Lixia Zhou, UCB 0.5m rad 1m rad 8m rad

ksjp, 7/01 MEMS Design & Fab 2D beam scanning laser lens CMOS ASIC Steering Mirror AR coated dome

ksjp, 7/01 MEMS Design & Fab 6-bit DAC Driving Scanning Mirror Open loop control Insensitive to disturbance Potentially low power

ksjp, 7/01 MEMS Design & Fab ~8mm 3 laser scanner Two 4-bit mechanical DACs control mirror scan angles. ~6 degrees azimuth, 3 elevation

ksjp, 7/01 MEMS Design & Fab Optical Communication 0-25%25% Path loss Loss = A receiver / (4  d 2 ) / G ant Antenna Gain = 4  /  ½ 2

ksjp, 7/01 MEMS Design & Fab Theoretical Performance P total = 100uW P t = 10uW  ½ = 1mrad BR = 5 Mbps A receiver = 0.1mm 2 P r = 10nW (-50dBm) P total = 50uW SNR = 15 dB 5m 20pJ/bit!

ksjp, 7/01 MEMS Design & Fab Theoretical Performance P total = 50mW P t = 5mW  ½ = 1mrad BR = 2 Mbps A receiver = 1m 2 P r = 10nW (-50dBm) P total = 50uW /pixel SNR = 17 dB 500km 25nJ/bit!

ksjp, 7/01 MEMS Design & Fab Satellite Imagery

ksjp, 7/01 MEMS Design & Fab Goal:10 Mbps; 10 km; 1 cm 3

ksjp, 7/01 MEMS Design & Fab 1 Mbps CMOS imaging receiver

ksjp, 7/01 MEMS Design & Fab Augmented Reality Lau, Muller, Solgaard and students

ksjp, 7/01 MEMS Design & Fab Laser pointer projector R G B Erase Clear 3axis gyro 2D RGB projector Stabilized laser pointer Hand-held projector Virtual whiteboard Track user motions while drawing Refresh at 30 Hz

ksjp, 7/01 MEMS Design & Fab Displays and screen doors Display Array of pixels RGB(x,y) RGB(x,y, ,  ) Screen door

ksjp, 7/01 MEMS Design & Fab Virtual window Pixel array Each pixel like a pinhole camera Max pixel power: 5mW out, 5mm^2  Array power (out): 1kW/m^2 Power in: 50mW/pixel Power in: 10kW/m^2 !

ksjp, 7/01 MEMS Design & Fab HDTV window Pixel array 2000x1000 array 1mm^2, 1mW out pixels Full video on each pixel Optical power out: 2kW Shadows Heat! (w/o sunburn) Home defense Uncompressed data rate: ~20 Tbps

ksjp, 7/01 MEMS Design & Fab HDTV window – more realistic Pixel array Eye tracking (multi-user) ~25/cones/pixel/face Data rates ~few video streams 10W/m^2 (bright indoor) 10uW/pixel average Array power << kW For each pixel For each face draw 5x5 grid ;