Patent US4794265A successfully refreshed from Google Patents.
US4794265A
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Surface pit detection system and method
Assignee: QC Optics Inc
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Filing: 1987-05-08
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Granted: 1988-12-27
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Expires: 2007-05-08
Abstract
Abstract An apparatus and method for uniquely detecting pits on a smooth surface by irradiating an area of the surface; separately sensing radiation scattered from the surface in the near-specular region indicative of a pit and in the far-specular region indicative of a flaw and producing signals representative thereof; normalizing the near-specular signal with respect to the far-specular signal to indicate a pit; and discriminating the near-specular components of the normalized signal representative of surface pits.
Inventors
- 👤 George S. Quackenbos
- 👤 Jay L. Ormsby
- 👤 Eric T. Chase
- 👤 Sergey V. Broude
- 👤 Koichi Nishine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:01
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/9506
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
84 words
A detection system for uniquely defining pits on a smooth surface comprising: means for directing a beam of radiation to a surface; means for separately sensing radiation scattered from the surface in the near-specular region and in the far-specular region and producing signals representative thereof; means, responsive to said means for sensing, for normalizing the near-specular signal with respect to the far-specular signal to provide a normalized near-specular signal; and means for discriminating the near-specular components of said normalized signal representative of surface pits.
Claim 2
Dependent Claim
84 words
A detection system for uniquely defining pits on a smooth surface comprising: means for directing a beam of radiation to a surface; means for separately sensing radiation scattered from the surface in the near-specular region and in the far-specular region and producing signals representative thereof; means, responsive to said means for sensing, for normalizing the near-specular signal with respect to the far-specular signal to provide a normalized near-specular signal; and means for discriminating the near-specular components of said normalized signal representative of surface pits.
Claim 3
Dependent Claim
18 words
The device of claim 1 in which said means for directing includes lens means and a radiation source.
Claim 4
Dependent Claim
14 words
The device of claim 2 in which said radiation source provides a collimated beam.
Claim 5
Dependent Claim
14 words
The device of claim 2 in which said radiation source provides a coherent beam.
Claim 6
Dependent Claim
13 words
The device of claim 2 in which said radiation source is a laser.
Claim 7
Dependent Claim
18 words
The device of claim 1 further including means for providing relative motion between said beam and the surface.
Claim 8
Dependent Claim
25 words
The device of claim 6 in which said means for providing relative motion moves said beam and surface in two directions relative to one another.
Claim 9
Dependent Claim
27 words
The device of claim 7 in which said means for providing relative motion includes means for rotating said surface and translating said surface relative to said beam.
Claim 10
Dependent Claim
39 words
The device of claim 1 in which said means for sensing includes means for separating radiation scattered in the near-specular region from other radiation and a sensor for receiving said near-specular scattered radiation and producing a signal representative thereof.
Claim 11
Dependent Claim
32 words
The device of claim 9 in which said means for separating includes means for directing specular radiation to one destination, far-specular radiation to a second destination and near-specular radiation to said sensor.
Claim 12
Dependent Claim
74 words
A detector apparatus for uniquely defining pits on a smooth surface, comprising: means for separately sensing radiation scattered from the surface in the near-specular region and in the far-specular region and producing signals representative thereof; and means, responsive to said means for sensing, for normalizing the near-specular signal with respect to the far-specular signal to provide a near-specular signal; and means for discriminating the near-specular components of said normalized signal representative of surface pits.
Claim 13
Dependent Claim
74 words
A detector apparatus for uniquely defining pits on a smooth surface, comprising: means for separately sensing radiation scattered from the surface in the near-specular region and in the far-specular region and producing signals representative thereof; and means, responsive to said means for sensing, for normalizing the near-specular signal with respect to the far-specular signal to provide a near-specular signal; and means for discriminating the near-specular components of said normalized signal representative of surface pits.
Claim 14
Dependent Claim
28 words
The device of claim 11 in which said means for separately sensing includes a first sensor for sensing near-specular radiation and a second sensor for sensing far-specular radiation.
Claim 15
Dependent Claim
14 words
The device of claim 11 in which said means for normalizing includes a comparator.
Claim 16
Dependent Claim
30 words
The device of claim 13 in which said comparator receives said near-specular signal as a first polarity and said far-specular signal as a second opposite polarity and sums the signals.
Claim 17
Dependent Claim
17 words
The device of claim 13 in which said comparator subtracts said near-specular signal from said far-specular signal.
Claim 18
Dependent Claim
30 words
The device of claim 14 in which said means for discriminating the near-specular components includes a first detector circuit for detecting components of said first polarity of said normalized signal.
Claim 19
Dependent Claim
21 words
The device of claim 11 further including means for discriminating far-specular components of said normalized signal representative of other surface flaws.
Claim 20
Dependent Claim
44 words
The device of claim 14 further including means for discriminating far-specular components of said normalized signal representative of other surface flaws, said means for discriminating the far-specular components including a second detector circuit for detecting components of said second polarity of said normalized signal.
Claim 21
Dependent Claim
27 words
The device of claim 11 further including a size determination circuit for classifying the near-specular component of said normalized signal into one of a plurality of sizes.
Claim 22
Dependent Claim
25 words
The device of claim 11 further including means for locating the position of the surface pit represented by said near-specular component of said normalized signal.
Claim 23
Independent Claim
69 words
A method of uniquely detecting pits on a smooth surface, comprising: irradiating an area of a surface; separately sensing radiation scattered from the surface in the near-specular region indicative of a pit and in the far-specular region indicative of a flaw and producing signals representative thereof; normalizing the near-specular signal with respect to the far-specular signal; and discriminating the near-specular components of the normalized signal representative of surface pits.
Claim 24
Independent Claim
69 words
A method of uniquely detecting pits on a smooth surface, comprising: irradiating an area of a surface; separately sensing radiation scattered from the surface in the near-specular region indicative of a pit and in the far-specular region indicative of a flaw and producing signals representative thereof; normalizing the near-specular signal with respect to the far-specular signal; and discriminating the near-specular components of the normalized signal representative of surface pits.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-27 | 1992-06-27 | 1992-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-27 | 1996-06-27 | 1996-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-27 | 2000-06-27 | 2000-12-27 | $7700.00 | Window Closed / Lapsed |