US4928527A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and device for nondestructive evaluation
Assignee: Nokia Bell Labs
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Filing: 1988-04-29
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Granted: 1990-05-29
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Expires: 2008-04-29
Abstract
Abstract Ultrasonic surface examination, of interest in a variety of manufacturing and maintenance situations, is facilitated by a method which involves localized sensing of a surface wave by optical-fiber interferometry. The method is particularly applicable for examination of surfaces in confined spaces and wherever line-of-sight examination is difficult.
Inventors
- 👤 Christian P. Burger
- 👤 Thomas D. Dudderar
- 👤 John A. Gilbert
- 👤 Bruce R. Peters
- 👤 James A. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:27
CPC Classifications
G; G01; G01N; G01N21/00; G01N29/00; G01N29/22; G01N29/24; G01N29/2418; G01H; G01H9/00; G01H9/004; G01H9/006; G01N21/84; G01N21/88; G01J; G01J9/00; G01J9/02; G01J2009/0226; G01N2291/00; G01N2291/04; G01N2291/042; G01N2291/0423
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
171 words
In the manufacture or maintenance of an article, a method for examining at least a portion of a surface of said article with respect to inhomogeneity of a surface property, said method comprising (i) providing energy to said surface, and (ii) sensing a surface wave at least at a point of said portion, characterized in that sensing of said surface wave comprises fiber-optical interferometry between first and second optical signals here designated as reference and object signals, said reference and object signals being derived from an optical signal here designated as laser signal and having been transmitted by an optical fiber, said first optical signal being derived from said laser signal by internal reflection of a first portion of the power of said laser signal at the end of said optical fiber, and said second optical signal being derived from said laser signal by emission of a second portion of the power of said laser signal from the end of said fiber, followed by reflection from said surface at said point.
Claim 2
Dependent Claim
171 words
In the manufacture or maintenance of an article, a method for examining at least a portion of a surface of said article with respect to inhomogeneity of a surface property, said method comprising (i) providing energy to said surface, and (ii) sensing a surface wave at least at a point of said portion, characterized in that sensing of said surface wave comprises fiber-optical interferometry between first and second optical signals here designated as reference and object signals, said reference and object signals being derived from an optical signal here designated as laser signal and having been transmitted by an optical fiber, said first optical signal being derived from said laser signal by internal reflection of a first portion of the power of said laser signal at the end of said optical fiber, and said second optical signal being derived from said laser signal by emission of a second portion of the power of said laser signal from the end of said fiber, followed by reflection from said surface at said point.
Claim 3
Dependent Claim
14 words
The method of claim 1 in which said energy is provided by piezoelectric means.
Claim 4
Dependent Claim
14 words
The method of claim 1 in which said energy is provided by optical means.
Claim 5
Dependent Claim
15 words
The method of claim 3 in which said energy is provided via an optical fiber.
Claim 6
Dependent Claim
15 words
The method of claim 1 in which fiber-optical interferometry comprises use of a single-mode fiber.
Claim 7
Dependent Claim
17 words
The method of claim 1 in which a lens is used to collimate light at said point.
Claim 8
Dependent Claim
24 words
The method of claim 1 in which a bidirectional optical coupler is used to couple radiation returning from said point into an interferometric analyzer.
Claim 9
Dependent Claim
17 words
The method of claim 1 in which reference and object signals are transmitted by different optical fibers.
Claim 10
Independent Claim
172 words
A device for examining at least a portion of a surface of an article with respect to inhomogeneity of a surface property, said device comprising (i) first means for providing energy to said surface, and (ii) second means for sensing a surface wave at least at a point of said portion, characterized in that said second means comprises a fiberoptical interferometer comprising a laser, an optical fiber disposed to accept an optical signal from said laser, and analyzing means for interferometrically analyzing first and second optical signals derived from an optical signal transmitted by said fiber and here designated as laser signal, said first optical signal being derived from said laser signal by internal; reflection of a first portion of the power of said laser signal at the end of said optical fiber, and said second optical signal being derived from said laser signal by emission of a second portion of the power of said laser signal from the end of said fiber, followed by reflection from said surface at said point.
Claim 11
Independent Claim
172 words
A device for examining at least a portion of a surface of an article with respect to inhomogeneity of a surface property, said device comprising (i) first means for providing energy to said surface, and (ii) second means for sensing a surface wave at least at a point of said portion, characterized in that said second means comprises a fiberoptical interferometer comprising a laser, an optical fiber disposed to accept an optical signal from said laser, and analyzing means for interferometrically analyzing first and second optical signals derived from an optical signal transmitted by said fiber and here designated as laser signal, said first optical signal being derived from said laser signal by internal; reflection of a first portion of the power of said laser signal at the end of said optical fiber, and said second optical signal being derived from said laser signal by emission of a second portion of the power of said laser signal from the end of said fiber, followed by reflection from said surface at said point.
Claim 12
Dependent Claim
14 words
The device of claim 9 in which said first means comprises a piezoelectric transducer.
Claim 13
Dependent Claim
16 words
The device of claim 9 in which said first means comprises a source of electromagnetic radiation.
Claim 14
Dependent Claim
18 words
The device of claim 11 in which said first means comprises an optical fiber coupled to said source.
Claim 15
Dependent Claim
14 words
The device of claim 9 in which said second means comprises a single-mode fiber.
Claim 16
Dependent Claim
13 words
The device of claim 9 in which said second means comprises collimating means.
Claim 17
Dependent Claim
15 words
The device of claim 9 in which said second means comprises a bidirectional optical coupler.
Claim 18
Dependent Claim
14 words
The device of claim 9 in which said second means comprises two optical fibers.
References Cited (Backward Citations)
US4381676A
Cited
US4619529A
Cited
US4572949A
Cited
US4652744A
Cited
US4723448A
Cited
US4824251A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-05-28 | 1993-11-27 | 1994-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-28 | 1997-11-27 | 1998-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-28 | 2001-11-27 | 2002-05-29 | $7700.00 | Window Closed / Lapsed |