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Title: Micromachined low frequency rocking accelerometer with capacitive pickoff

Abstract

A micro electro mechanical sensor that uses capacitive readout electronics. The sensor involves a micromachined low frequency rocking accelerometer with capacitive pickoff fabricated by deep reactive ion etching. The accelerometer includes a central silicon proof mass, is suspended by a thin polysilicon tether, and has a moving electrode (capacitor plate or interdigitated fingers) located at each end the proof mass. During movement (acceleration), the tethered mass moves relative to the surrounding packaging, for example, and this defection is measured capacitively by a plate capacitor or interdigitated finger capacitor, having the cooperating fixed electrode (capacitor plate or interdigitated fingers) positioned on the packaging, for example. The micromachined rocking accelerometer has a low frequency (<500 Hz), high sensitivity (.mu.G), with minimal power usage. The capacitors are connected to a power supply (battery) and to sensor interface electronics, which may include an analog to digital (A/D) converter, logic, RF communication link, antenna, etc. The sensor (accelerometer) may be, for example, packaged along with the interface electronics and a communication system in a 2".times.2".times.2" cube. The proof mass may be asymmetric or symmetric. Additional actuating capacitive plates may be used for feedback control which gives a greater dynamic range.

Inventors:
 [1];  [2];  [3]
  1. (Arlington, VA)
  2. (San Leandro, CA)
  3. (Livermore, CA)
Issue Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
873725
Patent Number(s):
6230566
Assignee:
Regents of University of California (Oakland, CA) LLNL
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
micromachined; frequency; rocking; accelerometer; capacitive; pickoff; micro; electro; mechanical; sensor; readout; electronics; involves; fabricated; deep; reactive; etching; central; silicon; proof; mass; suspended; polysilicon; tether; moving; electrode; capacitor; plate; interdigitated; fingers; located; movement; acceleration; tethered; moves; relative; surrounding; packaging; example; defection; measured; capacitively; finger; cooperating; fixed; positioned; 500; hz; sensitivity; minimal; power; usage; capacitors; connected; supply; battery; interface; analog; digital; converter; logic; rf; communication; link; antenna; etc; packaged; times; cube; asymmetric; symmetric; additional; actuating; plates; feedback; control; dynamic; range; dynamic range; power supply; feedback control; rocking accelerometer; capacitive pickoff; power usage; minimal power; frequency rocking; mechanical sensor; communication link; capacitive plate; capacitor plate; /73/

Citation Formats

Lee, Abraham P., Simon, Jonathon N., and McConaghy, Charles F. Micromachined low frequency rocking accelerometer with capacitive pickoff. United States: N. p., 2001. Web.
Lee, Abraham P., Simon, Jonathon N., & McConaghy, Charles F. Micromachined low frequency rocking accelerometer with capacitive pickoff. United States.
Lee, Abraham P., Simon, Jonathon N., and McConaghy, Charles F. Mon . "Micromachined low frequency rocking accelerometer with capacitive pickoff". United States. https://www.osti.gov/servlets/purl/873725.
@article{osti_873725,
title = {Micromachined low frequency rocking accelerometer with capacitive pickoff},
author = {Lee, Abraham P. and Simon, Jonathon N. and McConaghy, Charles F.},
abstractNote = {A micro electro mechanical sensor that uses capacitive readout electronics. The sensor involves a micromachined low frequency rocking accelerometer with capacitive pickoff fabricated by deep reactive ion etching. The accelerometer includes a central silicon proof mass, is suspended by a thin polysilicon tether, and has a moving electrode (capacitor plate or interdigitated fingers) located at each end the proof mass. During movement (acceleration), the tethered mass moves relative to the surrounding packaging, for example, and this defection is measured capacitively by a plate capacitor or interdigitated finger capacitor, having the cooperating fixed electrode (capacitor plate or interdigitated fingers) positioned on the packaging, for example. The micromachined rocking accelerometer has a low frequency (<500 Hz), high sensitivity (.mu.G), with minimal power usage. The capacitors are connected to a power supply (battery) and to sensor interface electronics, which may include an analog to digital (A/D) converter, logic, RF communication link, antenna, etc. The sensor (accelerometer) may be, for example, packaged along with the interface electronics and a communication system in a 2".times.2".times.2" cube. The proof mass may be asymmetric or symmetric. Additional actuating capacitive plates may be used for feedback control which gives a greater dynamic range.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2001},
month = {1}
}

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