US4030836A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for mapping surfaces with respect to ellipsometric parameters
Assignee: United States Department of the Air Force
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Filing: 1975-10-28
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Granted: 1977-06-21
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Expires: 1995-10-28
Abstract
Abstract Ellipsometric parameters for a given structural member surface area are obtained by scanning the structural member surface area at an oblique angle with a polarized monochromatic light beam and receiving the reflected light beam with a rotating analyzer. The rotating analyzer outputs are detected at its 0°, 45° and 90° azimuth orientations by a photodetector. The photodetector outputs can be plotted in their proper relationship to the scanned surface area boundaries to provide maps useful in nondestructive testing and other applications. Equations are provided that permit the conversion of the photodetector outputs into ellipsometric physical parameter values for refractive index, absorption coefficient and material thickness. Scanning in one embodiment is accomplished by a structural member holding device that can be simultaneously rotated and vertically translated.
Inventors
- 👤 Tennyson Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 03:45
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/21; G01N21/211
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
190 words
The method of mapping and utilizing for nondestructive testing purposes certain ellipsometric parameters of a discrete surface area of a structural member comprising the steps of scanning said discrete surface area from an oblique angle with a polarized monochromatic light beam, analyzing the light beam reflected from said surface area with a rotating analyzer, detecting with detector means the outputs of the rotating analyzer, recording the output values of the detector means for rotating analyzer azimuth orientation of 0°, 45° and 90° at a multiplicity of positions along each sweep of light beam scan, deriving ellipsometric parameters from said recorded output values by means of equations ##EQU2## plotting, for each rotating analyzer azimuth orientation, the ellipsometric parameter values at their appropriate coordinate positions relative to the scanned surface area boundaries, converting the derived ellipsometric parameter values into values of ellipsometric physical parameters for refractive index, absorption coefficient and material thickness, plotting said ellipsometric physical parameter values at their appropriate coordinate positions relative to the scanned surface area boundaries, and correlating said plotted ellipsometric parameter values and said plotted ellipsometric physical parameter values with an S-map of said discrete surface area.
Claim 2
Independent Claim
190 words
The method of mapping and utilizing for nondestructive testing purposes certain ellipsometric parameters of a discrete surface area of a structural member comprising the steps of scanning said discrete surface area from an oblique angle with a polarized monochromatic light beam, analyzing the light beam reflected from said surface area with a rotating analyzer, detecting with detector means the outputs of the rotating analyzer, recording the output values of the detector means for rotating analyzer azimuth orientation of 0°, 45° and 90° at a multiplicity of positions along each sweep of light beam scan, deriving ellipsometric parameters from said recorded output values by means of equations ##EQU2## plotting, for each rotating analyzer azimuth orientation, the ellipsometric parameter values at their appropriate coordinate positions relative to the scanned surface area boundaries, converting the derived ellipsometric parameter values into values of ellipsometric physical parameters for refractive index, absorption coefficient and material thickness, plotting said ellipsometric physical parameter values at their appropriate coordinate positions relative to the scanned surface area boundaries, and correlating said plotted ellipsometric parameter values and said plotted ellipsometric physical parameter values with an S-map of said discrete surface area.
References Cited (Backward Citations)
US2731878A
Cited
GB1089672A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-20 | 1980-12-20 | 1981-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-20 | 1984-12-20 | 1985-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-20 | 1988-12-20 | 1989-06-21 | $7700.00 | Window Closed / Lapsed |