US4455500A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sensitivity and capacitance adjustment method for piezoelectric accelerometers
Assignee: Ion Geophysical Corp
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Filing: 1983-07-28
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Granted: 1984-06-19
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Expires: 2003-07-28
Abstract
Abstract A dual-transducer accelerometer, having a liquid inertia mass is disclosed. Each transducer consists of a ceramic PZT piezo-electric wafer glued to a flexible substrate. Certain characteristics of sensitivity and capacitance of one transducer can be matched to similar characteristics of an arbitrarily-selected standard by laser-trimming the ceramic wafer.
Inventors
- 👤 Carl H. Savit
- 👤 Robert C. Shopland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:39
CPC Classifications
G; G01; G01P; G01P21/00; Y; Y10; Y10T; Y10T29/00; Y10T29/42
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
69 words
In a piezo-electric crystal transducer assembly including ceramic-wafer electroded sensing element, a method for adjusting the sensitivity and capacitance of the assembly relative to an arbitrarily-selected standard, comprising: laser-trimming a symmetrical pattern of vaporization spots on a ceramic wafer, the spots having desired dimensions of trim depth, trim area and trim-pattern distance and location, that are selected in accordance with a desired degree of adjustment in sensitivity and capacitance.
Claim 2
Dependent Claim
69 words
In a piezo-electric crystal transducer assembly including ceramic-wafer electroded sensing element, a method for adjusting the sensitivity and capacitance of the assembly relative to an arbitrarily-selected standard, comprising: laser-trimming a symmetrical pattern of vaporization spots on a ceramic wafer, the spots having desired dimensions of trim depth, trim area and trim-pattern distance and location, that are selected in accordance with a desired degree of adjustment in sensitivity and capacitance.
Claim 3
Dependent Claim
59 words
The method as defined by claim 1, comprising the steps of: laser-trimming a symmetrical pattern of vaporization spots on the ceramic wafer, said spots all having substantially constant depths and cross-sectional areas; and adjusting the sensitivity of said crystal assembly by adjusting the dimension and location of the spot pattern with respect to the center of said ceramic wafer.
Claim 4
Dependent Claim
77 words
The method as defined by claim 2, comprising the steps of: defining a critical distance for said ceramic wafer; increasing the sensitivity of a crystal transducer assembly in relationship to the distance of said spot pattern from said center when said spot pattern lies outboard of said critical distance; and decreasing the sensitivity of the crystal transducer assembly in relationship to the distance of said spot pattern when said spot pattern lies inboard of said critical distance.
Claim 5
Dependent Claim
60 words
The method as defined by claim 1, comprising the steps of: laser-trimming a spot pattern on a ceramic wafer, said spots having a substantially constant shallow trim depth, said spot pattern having a selected distance from center; and decreasing the sensitivity and capacitance, relative to said standard, of a crystal transducer assembly in relationship to the areas of said spots.
Claim 6
Dependent Claim
64 words
The method as defined by claim 1, comprising the steps of: laser-trimming a spot pattern on a ceramic wafer, said spots having a substantially constant intermediate trim depth, said spot pattern having a constant selected distance from center; and decreasing the capacitance, relative to said standard, of a crystal transducer assembly in relation to the areas of said spots without substantially altering the sensitivity.
Claim 7
Dependent Claim
70 words
The method as defined by claim 1, comprising: laser-trimming a spot pattern on a ceramic wafer, said spots having a substantially constant deep trim depth, said spot pattern having a selected constant distance from center; and decreasing the capacitance of a crystal transducer assembly relative to a standard in relation to the spot areas; increasing the sensitivity of the assembly relative to the standard in relationship to the spot areas.
Claim 8
Dependent Claim
59 words
The method as defined by claim 1, comprising the further steps of: laser-trimming a pattern of spots on a ceramic wafer, said spots having a substantially constant area, the spot pattern being positioned around a constant selected radius; and increasing the sensitivity, relative to the standard, of a crystal transducer assembly in relation to the depths of said spots.
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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) | 1987-06-19 | 1987-12-19 | 1988-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-19 | 1991-12-19 | 1992-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-19 | 1995-12-19 | 1996-06-19 | $7700.00 | Window Closed / Lapsed |