US5764345A
Expired / Lapsed
US
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Methods for detecting inhomogeneities, specifically, striae, infused silica glasses
Assignee: Corning Inc
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Filing: 1996-09-11
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Granted: 1998-06-09
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Expires: 2016-09-11
Abstract
Abstract A process for detecting inhomogeneities, specifically, striae in a sample of fused silica glass is provided which includes the steps of: preparing a digitized phase plot for the sample using an interferometer which produces a beam of light which passes through the sample; applying a high pass filter to the phase plot to remove the effects of the sample's bulk properties; applying a statistical filter to the high pass filtered data to remove outlying data points; and column averaging the statistically filtered data. If present, striae can be readily detected in the column averaged, statistically filtered data.
Inventors
- 👤 David R. Fladd
- 👤 Stephen J. Rieks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:54
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/958; G01M; G01M11/00; G01M11/02; G01M11/0242; G01M11/0271; G01N21/17; G01N21/41; G01N21/45; G01N21/455; G03; G03F; G03F7/00; G03F7/70; G03F7/70483; G03F7/70591; G03F7/706; G03F7/708; G03F7/7095; G03F7/70958
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
174 words
A method for testing a transparent body for the presence of striae comprising the steps of: (a) preparing a digitized phase plot for the transparent body using an interferometer, wherein: (i) the interferometer produces a beam of light which passes through the transparent body; and (ii) the digitized phase plot comprises a set of first values at a set of first locations on the body; (b) applying a high pass filter to the set of first values, said high pass filter producing a set of second values at a set of second locations on the body; (c) applying a statistical filter to the set of second values to remove outlying values, said statistical filter producing a set of third values at a set of third locations on the body; (d) column averaging the set of third values to produce a set of fourth values at the set of second locations on the body; and (e) examining the set of fourth values at the set of second locations to detect striae within the transparent body.
Claim 2
Independent Claim
174 words
A method for testing a transparent body for the presence of striae comprising the steps of: (a) preparing a digitized phase plot for the transparent body using an interferometer, wherein: (i) the interferometer produces a beam of light which passes through the transparent body; and (ii) the digitized phase plot comprises a set of first values at a set of first locations on the body; (b) applying a high pass filter to the set of first values, said high pass filter producing a set of second values at a set of second locations on the body; (c) applying a statistical filter to the set of second values to remove outlying values, said statistical filter producing a set of third values at a set of third locations on the body; (d) column averaging the set of third values to produce a set of fourth values at the set of second locations on the body; and (e) examining the set of fourth values at the set of second locations to detect striae within the transparent body.
Claim 3
Dependent Claim
64 words
The method of claim 1 wherein step (b) is performed by: (i) low pass filtering the set of first values to produce a set of low pass filtered values at the set of second locations; and (ii) subtracting the set of low pass filtered values from the set of first values to produce the set of second values at the set of second locations.
Claim 4
Dependent Claim
20 words
The method of claim 2 wherein the low pass filtering comprises local average filtering of the set of first values.
Claim 5
Dependent Claim
29 words
The method of claim 3 wherein the set of second locations comprises the set of first locations minus locations along the outer edges of the set of first locations.
Claim 6
Dependent Claim
21 words
The method of claim 2 wherein the low pass filtering comprises fitting a Zernike polynomial to the set of first values.
Claim 7
Dependent Claim
20 words
The method of claim 5 wherein the set of first locations and the set of second locations are the same.
Claim 8
Dependent Claim
20 words
The method of claim 1 wherein the set of third locations is a subset of the set of second locations.
Claim 9
Dependent Claim
19 words
The method of claim 1 wherein the set of third locations is identical to the set of second locations.
Claim 10
Dependent Claim
20 words
The method of claim 1 wherein step (e) comprises applying a quality control criterium to the set of fourth values.
Claim 11
Dependent Claim
24 words
The method of claim 9 wherein the set of fourth values is transformed into a line profile before the quality control criterium is applied.
Claim 12
Dependent Claim
12 words
The method of claim 1 wherein the interferometer includes a beam reducer.
Claim 13
Dependent Claim
14 words
The method of claim 1 wherein the transparent body is composed of fused silica.
Claim 14
Independent Claim
62 words
A method for testing a transparent body for the presence of striae comprising the steps of: (a) preparing a digitized phase plot for the body using an interferometer which produces a beam of light which passes through the transparent body; (b) column averaging the digitized phase plot; and (e) examining the column averaged phase plot to detect striae within the transparent body.
Claim 15
Independent Claim
62 words
A method for testing a transparent body for the presence of striae comprising the steps of: (a) preparing a digitized phase plot for the body using an interferometer which produces a beam of light which passes through the transparent body; (b) column averaging the digitized phase plot; and (e) examining the column averaged phase plot to detect striae within the transparent body.
Claim 16
Dependent Claim
24 words
The method of claim 13 including the additional step between steps (a) and (b) of applying a high pass filter to the phase plot.
Claim 17
Dependent Claim
43 words
The method of claim 13 including the additional steps between steps (a) and (b) of: (i) applying a high pass filter to the phase plot; and (ii) applying a statistical filter to the results of the high pass filter to remove statistical outliers.
Claim 18
Dependent Claim
12 words
The method of claim 13 wherein the interferometer includes a beam reducer.
Claim 19
Dependent Claim
14 words
The method of claim 13 wherein the transparent body is composed of fused silica.
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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) | 2001-06-08 | 2001-12-08 | 2002-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-08 | 2005-12-08 | 2006-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-08 | 2009-12-08 | 2010-06-09 | $7700.00 | Window Closed / Lapsed |