Patent US3989387A successfully refreshed from Google Patents.
US3989387A
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Method and apparatus for detecting optical defects in transparent sheets
Assignee: Saint Gobain Industries SA
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Filing: 1974-12-11
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Granted: 1976-11-02
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Expires: 1994-12-11
Abstract
Abstract Apparatus for detecting and measuring imperfections such as wedge, combing and lack of planarity in transparent sheets such as glass comprises an extended luminous source, focusing means to form a convergent beam containing an image of the source, a differential photoelectric cell positioned to receive that image after passage of that beam through, or reflection thereof at, the sheet, and circuit means connected with the cell for producing a changed output upon shift of the image on the cell due to changed refraction or reflection of the beam at the sheet produced by a defect. The beam of focused light is limited or stopped so that a cross-sectional dimension thereof is of the same order of magnitude as the width of typical defects in the sheets. According to the method of the invention the sheet is advanced in its own plane relatively to the source, focusing means, cell and stop, in a direction parallel to the width dimension of the defects in the sheet, this direction of motion being parallel to the said cross-sectional dimension of the beam.
Inventors
- 👤 Stephane Hategan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:07
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/89; G01N21/892; G01N21/896
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
109 words
Apparatus for testing a body for optical defects, said apparatus comprising: a. an extended luminous source, b. focusing means for forming, from light from said source, an image of said source at an image location, c. means to support said body in the path of the beam at a position between said focusing means and sasd image location, d. a photoelectric cell disposed substantially at said image location, said cell having an extended light-sensitive element and being responsive to the positional shift of said image on said element, and e. circuit means connected with said cell for producing an output signal upon displacement of said image on said element.
Claim 2
Dependent Claim
109 words
Apparatus for testing a body for optical defects, said apparatus comprising: a. an extended luminous source, b. focusing means for forming, from light from said source, an image of said source at an image location, c. means to support said body in the path of the beam at a position between said focusing means and sasd image location, d. a photoelectric cell disposed substantially at said image location, said cell having an extended light-sensitive element and being responsive to the positional shift of said image on said element, and e. circuit means connected with said cell for producing an output signal upon displacement of said image on said element.
Claim 3
Dependent Claim
24 words
Apparatus according to claim 1 further including indicator means responsive to said output signal, said indicator means being electrically connected to said circuit means.
Claim 4
Dependent Claim
48 words
Apparatus according to claim 1 wherein said image-forming means includes at least one focusing element, to form said image of said extended luminous source and at least one anamorphic element positioned between said position where the body is supported and said cell to render said image substantially equidimensional.
Claim 5
Dependent Claim
50 words
Apparatus according to claim 1 including a stop having an extended aperture to stop down said beam so that the area illuminated by said beam on said body is in at least one direction of a dimension of the same order of magnitude as the short dimension of said defect.
Claim 6
Dependent Claim
55 words
Apparatus according to claim 1 in which said apparatus includes means for supporting said source, image-forming means and cell on said apparatus, in position so that rays from said source are received from said body on said element, and means for moving one of said support means relative to the other to scan said body.
Claim 7
Dependent Claim
25 words
Apparatus according to claim 1 in which said apparatus includes means for supporting said source, image-forming means and cell on one side of said body.
Claim 8
Dependent Claim
73 words
Apparatus according to claim 6 further including reflecting means, said means for supporting said source, image-forming means and cell mounting said reflecting means in fixed relation with said luminous source, with said focusing means and with said cell so that said rays are received from said body by said reflecting means and are diverted by said reflecting means to said element, said reflecting means being supported on the other side of said body.
Claim 9
Dependent Claim
44 words
Apparatus according to claim 1 wherein said photoelectric cell includes at least one electrode disposed on one side of said element and in electrical contact therewith and a plurality of electrodes disposed on the other side of said element and in electrical contact therewith.
Claim 10
Dependent Claim
22 words
Apparatus according to claim 8 further including an insulating strip for insulating said electrodes of said plurality of electrodes from each other.
Claim 11
Independent Claim
101 words
A method of testing a body for optical defects comprising the steps of focusing light rays from an extended luminous source toward an image location, interposing said body in the path of said focused rays at a position between said source and said image location to illuminate said object over an area limited in at least one direction by a dimension of the same order of magnitude as the short dimension of a typical defect, advancing said body with a motion including a component parallel to said direction, and detecting shifts of the image of said source at said image location.
Claim 12
Independent Claim
101 words
A method of testing a body for optical defects comprising the steps of focusing light rays from an extended luminous source toward an image location, interposing said body in the path of said focused rays at a position between said source and said image location to illuminate said object over an area limited in at least one direction by a dimension of the same order of magnitude as the short dimension of a typical defect, advancing said body with a motion including a component parallel to said direction, and detecting shifts of the image of said source at said image location.
Claim 13
Dependent Claim
35 words
A method according to claim 10 wherein said focused rays are stopped in said direction to a dimension of the same order of magnitude as the short dimension of a typical defect in said body.
Claim 14
Dependent Claim
211 words
Apparatus for testing a body for optical defects, said apparatus comprising an extended luminous source, focusing means to form an image of said source at an image location, means to support said body in the path of a beam formed by said focusing means from light from said source at a position between said focusing means and said image location, a stop having an extended aperture and disposed in the path of said beam at a position between said focusing means and said position where the body is supported to stop down said beam so that the short dimension of the area illuminated by said beam on said body is of the same order of magnitude as the short dimension of a typical defect, a photoelectric cell disposed substantially at said image location, said cell having an extended light-sensitive element and being responsive to the positional shift of said image, an anamorphic element disposed in the path of said beam between said position where said body is supported and said cell to reduce the dimension of said image in a direction transverse to the long dimension of said element, said apparatus including circuit means connected with said cell for producing an output signal upon displacement of said image on said element.
Claim 15
Dependent Claim
211 words
Apparatus for testing a body for optical defects, said apparatus comprising an extended luminous source, focusing means to form an image of said source at an image location, means to support said body in the path of a beam formed by said focusing means from light from said source at a position between said focusing means and said image location, a stop having an extended aperture and disposed in the path of said beam at a position between said focusing means and said position where the body is supported to stop down said beam so that the short dimension of the area illuminated by said beam on said body is of the same order of magnitude as the short dimension of a typical defect, a photoelectric cell disposed substantially at said image location, said cell having an extended light-sensitive element and being responsive to the positional shift of said image, an anamorphic element disposed in the path of said beam between said position where said body is supported and said cell to reduce the dimension of said image in a direction transverse to the long dimension of said element, said apparatus including circuit means connected with said cell for producing an output signal upon displacement of said image on said element.
Claim 16
Dependent Claim
23 words
Apparatus according to claim 12 wherein said image has an intensity of illumination sufficiently great to saturate the illuminated area of said element.
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) | 1979-11-02 | 1980-05-03 | 1980-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-02 | 1984-05-03 | 1984-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-02 | 1988-05-03 | 1988-11-02 | $7700.00 | Window Closed / Lapsed |