Patent ID: 6550330
Filing Date: 2003-04-22
Classification: G01C

Abstract:
A high sensitivity micro-electro-mechanical optical accelerometer system comprising:first and second substantially identical optical accelerometers each including, an interferometer, including a pair of partially transmissive, partially reflective, surfaces wherein a first of said surfaces is flexibly suspended adjacent and parallel to a second of said surfaces so that a gap exists therebetween; a proof mass attached to said flexibly suspended first surface; and a photosensor attached to one of said surfaces outside of said gap, said photosensor for receiving light through said first and second surfaces wherein said light is also partially reflected between said surfaces; whereby a change in said gap due to an acceleration force is sensed by a change in said light as detected by said photosensor; a source of monochromatic light for irradiating said photosensors of said first and second optical accelerometers; a power supply for biasing said photosensors with a substantially equal amount of current and for providing a common supply voltage to said accelerometer system; wherein said gap of said first optical accelerometer is set so that said first optical accelerometer provides an increase in light transmission upon initially sensing said acceleration force and said gap of said second optical accelerometers is set so that said second optical accelerometer provides a decrease in light transmission upon initially sensing said acceleration force; and a differential circuit for subtracting a photosensor output of one of said optical accelerometers from a photosensor output of the other of said optical accelerometers.