US4950990A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for photoinductive imaging
Assignee: Iowa State University Research Foundation Inc
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Filing: 1989-07-21
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Granted: 1990-08-21
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Expires: 2009-07-21
Abstract
Abstract A system for photoinductive imaging for flaw detection of materials and for calibrating eddy-current probes includes positioning an eddy-current probe adjacent to a specimen to be analyzed or to be used as a calibration fixture. A source of thermal energy is modulated and focused to a localized area on the specimen. Thermal energy is then scanned across at least a portion of the detection area of the eddy-probe. The resulting signal from the eddy-current probe is recorded and can depict either thermal-influenced components of the specimen or the response pattern of the eddy-current probe. The record can therefore be used to image flaws or physical holes or shapes of the specimen or calibrate the eddy-current probe.
Inventors
- 👤 John C. Moulder
- 👤 James H. Rose
- 👤 Donald O. Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:01
CPC Classifications
B; B82; B82Y; B82Y15/00; G; G01; G01R; G01R35/00; G01R35/005
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
114 words
A method of photoinductive imaging for materials comprising: positioning a specimen material adjacent an eddy-current probe means having a detection area; generating a modulated thermal source; directing the modulated thermal source onto the specimen at a localized area on the specimen; scanning the localized area across the specimen coincident with at least a portion of the detection area of the probe means to cause generation of thermal waves which in turn cause temperature changes in the specimen; detecting with the probe means changes in electrical conductivity in the localized areas caused by localized temperature changes in the specimen; and recording the detected changes in electrical conductivity to create an image of the detection area.
Claim 2
Independent Claim
114 words
A method of photoinductive imaging for materials comprising: positioning a specimen material adjacent an eddy-current probe means having a detection area; generating a modulated thermal source; directing the modulated thermal source onto the specimen at a localized area on the specimen; scanning the localized area across the specimen coincident with at least a portion of the detection area of the probe means to cause generation of thermal waves which in turn cause temperature changes in the specimen; detecting with the probe means changes in electrical conductivity in the localized areas caused by localized temperature changes in the specimen; and recording the detected changes in electrical conductivity to create an image of the detection area.
Claim 3
Dependent Claim
32 words
The method of claim 1 further comprising raster scanning thermal source across the specimen to obtain an image of a portion of the specimen related to thermally absorbing features of the specimen.
Claim 4
Dependent Claim
31 words
The method of claim 2 further comprising raster scanning the thermal source across the specimen to obtain an image of the specimen including voids, cracks, holes, or geometries of the specimen.
Claim 5
Dependent Claim
16 words
The method of claim 1 further comprising scanning the probe and specimen past the thermal source.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein the thermal source comprises a beam of electromagnetic radiation.
Claim 7
Dependent Claim
68 words
A means of photoinductive imaging of a specimen comprising: an eddy-current probe positionable adjacent the specimen; a modulated thermal means for directing modulated thermal energy onto a localized area of the specimen; means for scanning the thermal energy across the specimen; and means for receiving signals from the eddy-current probe corresponding to changes in electrical conductivity in the localized areas caused by localized temperature changes in the specimen.
Claim 8
Dependent Claim
68 words
A means of photoinductive imaging of a specimen comprising: an eddy-current probe positionable adjacent the specimen; a modulated thermal means for directing modulated thermal energy onto a localized area of the specimen; means for scanning the thermal energy across the specimen; and means for receiving signals from the eddy-current probe corresponding to changes in electrical conductivity in the localized areas caused by localized temperature changes in the specimen.
References Cited (Backward Citations)
US4513384A
Cited
US4581576A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-20 | 1994-02-19 | 1994-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-20 | 1998-02-19 | 1998-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-20 | 2002-02-19 | 2002-08-21 | $7700.00 | Window Closed / Lapsed |