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US5952574A Expired / Lapsed US ⏱️ 0.0 years remaining

Trenches to reduce charging effects and to control out-of-plane sensitivities in tuning fork gyroscopes and other sensors

Assignee: Charles Stark Draper Laboratory Inc
•
Filing: 1997-04-29
•
Granted: 1999-09-14
•
Expires: 2017-04-29
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Abstract

Abstract Trenches which reduce or eliminate force and sensitivity associated with proof mass motion normal to the substrate as a result of voltage transients is disclosed. The trenches provide increased separation between interleaved comb electrodes and the substrate, and thereby also reduce the comb lift to drive ratio. The trenches are typically formed directly below the interleaved comb electrodes, but may also be formed below other suspended portions. Trench depth is from 6-10 microns and provides a comb electrode to substrate separation of approximately 8.5-12.5 microns.

Inventors

  • 👤 Marc S. Weinberg
  • 👤 Steven T. Cho
  • 👤 Ralph E. Hopkins, III
  • 👤 Lance C. Niles
  • 👤 Anthony S. Kourepenis
  • 👤 Eric M. Hildebrant
  • 👤 Paul A. Ward

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-06 02:39
CPC Classifications
G; G01; G01C; G01C19/00; G01C19/56; G01C19/5719

Claims Analysis

Total Claims: 23
Claim 1
Independent Claim 105 words
A drive for imparting a vibratory force to a vibrating member with a driving member, the vibrating member suspended above a surface of a substrate by a support flexure, comprising: first comb electrodes connected to the driving member; second comb electrodes connected to the vibrating member, said second comb electrodes interleaved with said first comb electrodes, an overlap region defined thereby, a gap being defined between the substrate surface and the interleaved comb electrodes; and a trench formed in the substrate substantially between the interleaved comb electrodes and the substrate such that the gap between the substrate surface and the interleaved comb electrodes is increased.
Claim 2
Dependent Claim 105 words
A drive for imparting a vibratory force to a vibrating member with a driving member, the vibrating member suspended above a surface of a substrate by a support flexure, comprising: first comb electrodes connected to the driving member; second comb electrodes connected to the vibrating member, said second comb electrodes interleaved with said first comb electrodes, an overlap region defined thereby, a gap being defined between the substrate surface and the interleaved comb electrodes; and a trench formed in the substrate substantially between the interleaved comb electrodes and the substrate such that the gap between the substrate surface and the interleaved comb electrodes is increased.
Claim 3
Dependent Claim 22 words
The drive of claim 1 wherein said trench has a width dimension which is greater than or equal to said overlap region.
Claim 4
Dependent Claim 21 words
The drive of claim 2 wherein said trench has a depth dimension which is from 6 μm to 10 μm, inclusive.
Claim 5
Dependent Claim 15 words
The drive of claim 3 wherein said trench is formed by a dissolved wafer process.
Claim 6
Dependent Claim 17 words
The drive of claim 2 wherein said trench has a depth dimension which is greater than 10μm.
Claim 7
Dependent Claim 30 words
The drive of claim 5 wherein said trench is formed by a technique selected from the group consisting of reactive ion etching, chlorine etching, SF 6 etching and anisotropic etching.
Claim 8
Dependent Claim 117 words
A tuning fork gyroscope comprising: a substrate with a surface; an outer drive with comb electrodes; an inner drive with comb electrodes; proof masses with inner and outer comb electrodes, said proof masses suspended above said substrate by support flexure, said inner comb electrodes interleaved with said inner drive comb electrodes and said outer comb electrodes interleaved with said outer drive comb electrodes, an overlap region defined by said interleaved comb electrodes, a gap being defined between the substrate surface and the interleaved comb electrodes; and trenches formed in said substrate substantially between said inner interleaved comb electrodes and said substrate such that the gap between said substrate surface and said inner interleaved comb electrodes is increased.
Claim 9
Dependent Claim 117 words
A tuning fork gyroscope comprising: a substrate with a surface; an outer drive with comb electrodes; an inner drive with comb electrodes; proof masses with inner and outer comb electrodes, said proof masses suspended above said substrate by support flexure, said inner comb electrodes interleaved with said inner drive comb electrodes and said outer comb electrodes interleaved with said outer drive comb electrodes, an overlap region defined by said interleaved comb electrodes, a gap being defined between the substrate surface and the interleaved comb electrodes; and trenches formed in said substrate substantially between said inner interleaved comb electrodes and said substrate such that the gap between said substrate surface and said inner interleaved comb electrodes is increased.
Claim 10
Dependent Claim 24 words
The tuning fork gyroscope of claim 7 wherein said trenches have a width dimension which is greater than or equal to said overlap region.
Claim 11
Dependent Claim 23 words
The tuning fork gyroscope of claim 8 wherein said trenches have a depth dimension which is from 6 μm to 10 μm, inclusive.
Claim 12
Dependent Claim 20 words
The tuning fork gyroscope of claim 8 wherein said trenches have a depth dimension which is greater than 10 μm.
Claim 13
Dependent Claim 29 words
The tuning fork gyroscope of claim 9 wherein said gap is increased by said trenches from about 2.5 μm to a gap from 8.5 μm to 12.5 μm, inclusive.
Claim 14
Dependent Claim 25 words
The tuning fork gyroscope of claim 8 wherein trenches are also formed in said substrate substantially between the outer interleaved comb electrodes and the substrate.
Claim 15
Dependent Claim 23 words
The tuning fork gyroscope of claim 12 wherein said trenches have a depth dimension which is from 6 μm to 10 μm, inclusive.
Claim 16
Dependent Claim 20 words
The tuning fork gyroscope of claim 12 wherein said trenches have a depth dimension which is greater than 10 μm.
Claim 17
Dependent Claim 29 words
The tuning fork gyroscope of claim 13 wherein said gap is increased by said trenches from about 2.5 μm to a gap from 8.5 μm to 12.5 μm, inclusive.
Claim 18
Dependent Claim 23 words
The tuning fork gyroscope of claim 7 wherein trenches are also formed in said substrate substantially between the support flexure and the substrate.
Claim 19
Dependent Claim 76 words
In a tuning fork gyroscope having interleaved comb electrodes defining an overlap region and a substrate surface with a gap defined therebetween, a method for alleviating undesirable effects of substrate voltage transients on gyroscope operation comprising the step of: increasing the gap between the interleaved comb electrodes and the substrate surface by forming a trench in the substrate substantially between the interleaved comb electrodes and the substrate in the overlap region of the interleaved comb electrodes.
Claim 20
Dependent Claim 76 words
In a tuning fork gyroscope having interleaved comb electrodes defining an overlap region and a substrate surface with a gap defined therebetween, a method for alleviating undesirable effects of substrate voltage transients on gyroscope operation comprising the step of: increasing the gap between the interleaved comb electrodes and the substrate surface by forming a trench in the substrate substantially between the interleaved comb electrodes and the substrate in the overlap region of the interleaved comb electrodes.
Claim 21
Dependent Claim 66 words
In a tuning fork gyroscope having interleaved comb electrodes and a substrate surface with a gap defined therebetween, and a support flexure, a method for alleviating undesirable effects of substrate voltage transients on gyroscope operation comprising the step of: increasing the gap between the interleaved comb electrodes and the substrate surface by forming trenches below the interleaved comb electrodes and forming trenches below the support flexure.
Claim 22
Dependent Claim 66 words
In a tuning fork gyroscope having interleaved comb electrodes and a substrate surface with a gap defined therebetween, and a support flexure, a method for alleviating undesirable effects of substrate voltage transients on gyroscope operation comprising the step of: increasing the gap between the interleaved comb electrodes and the substrate surface by forming trenches below the interleaved comb electrodes and forming trenches below the support flexure.
Claim 23
Dependent Claim 34 words
The method of claim 17 wherein said step of forming the trench is accomplished by a technique selected from the group consisting of reactive ion etching, chlorine etching, SF 6 etching and anisotropic etching.

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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2002-09-13 2003-03-15 2003-09-14 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2006-09-13 2007-03-15 2007-09-14 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2010-09-13 2011-03-15 2011-09-14 $7700.00 Window Closed / Lapsed

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