IR (Infrared) Night Vision Weapon Detection Security Monitoring Firefighting

IR Sensing –Photonic – absorbed photon excites electronic transitions Cryogenic cooled (77K) Most sensitive IR sensor (NETD = 5mK) –Thermal – absorbed radiation changes device temperature Operate at room temperature (uncooled) Less sensitive (NETD ~ 20 mK) Thermal IR sensors Supporting Leg Sensor Radiation Signal Supporting Substrate

CCD Beam Splitter Low Power Visible Laser Imaging Lens Focal Plane Array (FPA) of Bi-material Cantilever Temperature Sensors Infrared (IR) Source IR Antireflection Coating IR Absorber Visible Reflector FPA Side View IR Radiation Image Plane Image Process System Infrared Lens Cantilever IR Sensor Arrays

Cantilever Design Material selection –SiNx/Al IR optics ( SiNx ) –Resonant cavity (m / 2) Thermal design –IR absorption area –Minimum thermal conductance Thermomechanical design –Long bimaterial beam –Vacuum Packaging Bi-material Cantilever Anchor Thermal Isolation Leg Si Substrate IR absorber

Microfabrication Process High temperature process Metal deposition simultaneously on both layers after release Si substrate LPCVD PSG LPCVD SiNx LPCVD Poly Si Al Pt

( o C) Pixel size: 110  m Pixel Layout and Temperature Response Thermomechanical Response ~ 2  m/K

Experiment Setup and IR Imaging Result CCD He-Ne Laser Beam Splitter FPA Vacuum Chamber Temperature Control System IR Lens Beam Expander Imaging Lens IR imaging with background subtraction

Linearization Calibration Original image Linearly corrected Zhao, Mao, Horowitz, Majumdar, Varesi, Norton, Kitching, J. MEMS (2001)

Summary 10  m Nanotube Thermal Imaging Cancer Detection IR Night Vision An Example for ME381R: Micro-Nano Thermal-Fluid Science and Technology