US4028728A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and video system for identifying different light-reflective surface areas on articles
Assignee: AT&T Inc
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Filing: 1976-04-02
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Granted: 1977-06-07
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Expires: 1996-04-02
Abstract
Abstract Article surface defect detection methods and closed-circuit video systems for use therewith are disclosed for discriminating between different types of light-reflective surface areas on articles. Such methods and systems are particularly adapted to ascertain the presence and absence of, as well as condition of, circuit paths and satisfactory versus unsatisfactory soldered connections on printed circuit boards. In order to optimize the contrast between such two-dimensional and three-dimensional light-reflective surface areas, a specially oriented and polarized screen is interposed between the light source and article surface to be examined, and a rotatably adjustable polarized filter is preferably mounted on the camera, with the axis of the lens system thereof being oriented substantially perpendicularly to both the polarized light rays and the exposed article surface to be examined.
Inventors
- 👤 Benny H. Sharp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:39
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956; G01B; G01B11/00; G01B11/02; G01B11/022; G01N21/95684
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
201 words
A video system for selectively ascertaining the presence and absence of, and for discriminating between, at least two distinctively different types of light-reflective surface areas formed on a common, exposed surface of a prepositioned object, one type of surface area being substantially two-dimensional, and the other type being substantially three-dimensional, said system comprising: means for illuminating the exposed surface of said object with polarized light that extends across said surface such that in a direction at least substantially perpendicular thereto: (1) reflected light is minimized from those light-reflective areas on said surface having a substantially smooth, planar, two-dimensional profile, and (2) reflected light is maximized from those light-reflective areas on said surface having a three-dimensional profile; video camera means positioned such that the axis of said lens thereof is oriented substantially perpendicularly to both the exposed surface of the object and the light ray paths of said polarized light for receiving the minimized and maximized patterns of reflected light from said respectively different types of surface areas, and for generating video signals that produce contrasting patterns representative thereof when displayed on the screen of a video monitor, and a video monitor electrically connected to said camera for producing said contrasting patterns.
Claim 2
Dependent Claim
201 words
A video system for selectively ascertaining the presence and absence of, and for discriminating between, at least two distinctively different types of light-reflective surface areas formed on a common, exposed surface of a prepositioned object, one type of surface area being substantially two-dimensional, and the other type being substantially three-dimensional, said system comprising: means for illuminating the exposed surface of said object with polarized light that extends across said surface such that in a direction at least substantially perpendicular thereto: (1) reflected light is minimized from those light-reflective areas on said surface having a substantially smooth, planar, two-dimensional profile, and (2) reflected light is maximized from those light-reflective areas on said surface having a three-dimensional profile; video camera means positioned such that the axis of said lens thereof is oriented substantially perpendicularly to both the exposed surface of the object and the light ray paths of said polarized light for receiving the minimized and maximized patterns of reflected light from said respectively different types of surface areas, and for generating video signals that produce contrasting patterns representative thereof when displayed on the screen of a video monitor, and a video monitor electrically connected to said camera for producing said contrasting patterns.
Claim 3
Dependent Claim
22 words
A video system in accordance with claim 1 further comprising: a polarized lens disposed between said camera and said object being viewed.
Claim 4
Dependent Claim
116 words
A video system in accordance with claim 2 wherein said means for producing polarized light rays comprises at least two mutually disposed light sources having axially disposed, elongated tubular bulbs confining elongated filaments therewithin, each bulb being positioned slightly above and extending in the direction of a different one of two opposed edges of said object, and polarized filter means positioned adjacent to and extending along the mutually opposed sides of said light sources, said filter means, in conjunction with said polarized lens when properly oriented, resulting in at least selected surface regions on any contoured three-dimensional surface areas being highlighted by said polarized light, and represented with maximum definition on the screen of said monitor.
Claim 5
Dependent Claim
31 words
A video system in accordance with claim 3 wherein said polarized filter means comprises a pair of substantially rectangular, planar polarized screens respectively positioned adjacent different ones of said light sources.
Claim 6
Dependent Claim
116 words
A video system in accordance with claim 2 wherein said means for producing polarized light rays comprises at least one light source with a substantially annular bulb dimensioned so as to circumscribe at least a predetermined surface portion of said object, and being positioned so as to overly the exposed surface to be examined, and polarized filter means of at least substantially cylindrical configuration positioned adjacent the inner circumference side of said light source, said filter means, in conjunction with said polarized lens when properly oriented, resulting in at least selected surface regions on any contoured three-dimensional surface areas being highlighted by said polarized light, and represented with maximum definition on the screen of said monitor.
Claim 7
Dependent Claim
43 words
A video system in accordance with claim 5 wherein at least said one light source comprises a fluorescent type lamp which is dimensioned to circumscribe the periphery of said object, and wherein said polarized lens is mounted on said camera and rotatably adjustable.
Claim 8
Dependent Claim
68 words
A video system in accordance with claim 4 wherein said light sources are of the incandescent filament type, and wherein said means for producing polarized light further includes a different reflector positioned adjacent the outer side of each of said light sources, and formed with an inner concave wall portion to direct concentrated reflected light across said exposed surface of said object at a desired angle relative thereto.
Claim 9
Dependent Claim
56 words
A video system in accordance with claim 5 wherein said means for producing polarized light further includes a cylindrical reflector positioned adjacent the outer side of said annular light source, and formed with a concave-defining inner wall portion to direct reflected light therefrom across the exposed surface of said object at a desired angle relative thereto.
Claim 10
Dependent Claim
53 words
A video system in accordance with claim 7 further comprising: an indexable table mounted beneath said light source, and wherein said object comprises a printed circuit board mounted on said table so as to allow selective portions of said circuit board to be positioned within the focused and reflected-light-receiving range of said camera.
Claim 11
Dependent Claim
53 words
A video system in accordance with claim 8 further comprising: an indexable table mounted beneath said light source, and wherein said object comprises a printed circuit board mounted on said table so as to allow selective portions of said circuit board to be positioned within the focused and reflected-light-receiving range of said camera.
Claim 12
Dependent Claim
39 words
A video system in accordance with claim 9 further comprising: means to selectively displace said circuit board and the combination of said light source, polarized screens and reflector relative to each other so as to alter the spacing therebetween.
Claim 13
Dependent Claim
40 words
A video system in accordance with claim 10 further comprising: means to selectively displace said circuit board and the combination of said light source, polarized filter means and reflector relative to each other so as to alter the spacing therebetween.
Claim 14
Dependent Claim
100 words
A video system in accordance with claim 11 wherein said surface areas on the printed circuit board having a substantially smooth, two-dimensional profile selectively comprise patterned circuit paths and terminals, which paths and terminals appear as dark gray areas on the screen of said monitor when operated in a black and white mode, whereas said surface areas having a contoured three-dimensional profile, such as satisfactory solder fillets, any abnormal solder bridges and icicles appearing randomly, and any scratches and pits in said normally smooth planar profiled surface areas, selectively and respectively appear as discrete, bright areas on said monitor screen.
Claim 15
Dependent Claim
100 words
A video system in accordance with claim 12 wherein said surface areas on the printed circuit board having a substantially smooth, two-dimensional profile selectively comprise patterned circuit paths and terminals, which paths and terminals appear as dark gray areas on the screen of said monitor when operated in a black and white mode, whereas said surface areas having a contoured, three-dimensional profile, such as satisfactory solder fillets, any abnormal solder bridges and icicles appearing randomly, and any scratches and pits in said normally smooth planar profiled surface areas, selectively and respectively appear as discrete, bright areas on said monitor screen.
Claim 16
Dependent Claim
69 words
A video system in accordance with claim 13 wherein a standard reference pattern, identifying the desired spatial locations of at least said circuit paths and desired solder connection areas associated therewith, is formed on a suitable medium which is mounted on said monitor, said reference pattern and medium being such as to allow direct, overlying comparison thereof with the circuit pattern being examined and displayed on said monitor screen.
Claim 17
Dependent Claim
69 words
A video system in accordance with claim 14 wherein a standard reference pattern, identifying the desired spatial locations of at least said circuit paths and desired solder connection areas associated therewith, is formed on a suitable medium which is mounted on said monitor, said reference pattern and medium being such as to allow direct, overlying comparison thereof with the circuit pattern being examined and displayed on said monitor screen.
Claim 18
Dependent Claim
87 words
A video system in accordance with claim 13 further comprising defect marking means, including indexable dot carrying transport means and vacuum controlled means, for successively picking up colored marking dots of suitable material from said transport means, and after transferring said vacuum-held dots respectively to each area on said circuit board identified as being defective by the particular reflected light pattern representative thereof displayed on said monitor, depositing each picked-up dot adjacent a different defective area by adjusting the magnitude of said vacuum applied against said dot.
Claim 19
Dependent Claim
86 words
A video system in accordance with claim 14 further comprising defect marking means, including indexable dot carrying transport means and vacuum controlled means, for successively picking up colored marking dots of suitable material from said transport means and transferring said dots respectively to each area on said circuit board identified as being defective by the particular reflected light pattern representative thereof displayed on said monitor, and depositing each picked-up dot adjacent a different defective area by adjusting the magnitude of said vacuum applied against said dot.
Claim 20
Dependent Claim
179 words
A video system for discriminating between two-dimensional and three-dimensional light-reflective patterned surface areas formed on an exposed, and at least substantially planar, surface of an article, said system comprising: means for illuminating the exposed planar surface of said article with polarized light that extends across said surface such that in a direction at least substantially perpendicular thereto: (1) reflected light is minimized from those light-reflective areas on said patterned surface having a substantially smooth, two-dimensional profile, and (2) reflected light is maximized from those light-reflective areas on said surface having a three-dimensional profile; video camera means positioned such that the axis of said lens thereof is oriented substantially perpendicularly to both the exposed planar surface of the article and the light ray paths of said polarized light, for receiving the minimized and maximized patterns of reflected light from said respectively different types of surface areas, and for generating video signals that produce contrasting patterns representative thereof when displayed on the screen of a video monitor; and a video monitor electrically connected to said camera for producing said contrasting patterns.
Claim 21
Dependent Claim
179 words
A video system for discriminating between two-dimensional and three-dimensional light-reflective patterned surface areas formed on an exposed, and at least substantially planar, surface of an article, said system comprising: means for illuminating the exposed planar surface of said article with polarized light that extends across said surface such that in a direction at least substantially perpendicular thereto: (1) reflected light is minimized from those light-reflective areas on said patterned surface having a substantially smooth, two-dimensional profile, and (2) reflected light is maximized from those light-reflective areas on said surface having a three-dimensional profile; video camera means positioned such that the axis of said lens thereof is oriented substantially perpendicularly to both the exposed planar surface of the article and the light ray paths of said polarized light, for receiving the minimized and maximized patterns of reflected light from said respectively different types of surface areas, and for generating video signals that produce contrasting patterns representative thereof when displayed on the screen of a video monitor; and a video monitor electrically connected to said camera for producing said contrasting patterns.
Claim 22
Dependent Claim
201 words
A video system in accordance with claim 19 wherein said means for producing polarized light comprises at least two mutually disposed light sources having axially disposed, elongated tubular bulbs confining elongated filaments therewithin, each bulb being positioned slightly above and extending in the direction of a different one of two opposed edges of said article, and polarized filter means positioned adjacent to and extending along the mutually opposed sides of said light sources, and wherein said video system further includes: reflector means positioned adjacent the outer sides of said light sources, and formed with an inner concave wall portion dimensioned so as to direct concentrated reflected light across said exposed surface of said article at an angle relative thereto that results in at least selected regions on any contoured three-dimensional surface areas producing a substantial amount of reflected light toward said camera and, thereby, producing respective bright areas representative thereof on the screen of said monitor; a rotatably adjustable polarized lens disposed between said camera and said article being viewed, and means to selectively displace said article and the combination of said light source, polarized filter means and reflector means relative to each other so as to alter the spacing therebetween.
Claim 23
Dependent Claim
201 words
A video system in accordance with claim 19 wherein said means for producing polarized light comprises at least one light source with a substantially annular bulb dimensioned so as to circumscribe at least a predetermined surface area of said article, and being positioned so as to overly the exposed surface to be examined, and polarized filter means of at least substantially cylindrical configuration positioned adjacent the inner circumference side of said light source, and wherein said video system further includes: cylindrical reflector means positioned adjacent the outer side of said annular light source, and formed with a concave-defining inner wall portion to direct reflected light therefrom across the exposed surface of said object at a desired angle relative thereto that results in at least selected regions on any contoured three-dimensional surface areas producing a substantial amount of reflected light toward said camera and, thereby, producing respective bright areas representative thereof on the screen of said monitor; a rotatably adjustable polarized lens disposed between said camera and said article being viewed; and means to selectively displace said article and the combination of said light source, polarized filter means and reflector means relative to each other so as to alter the spacing therebetween.
Claim 24
Dependent Claim
148 words
A video system in accordance with claim 20, further comprising: an indexable table mounted beneath said light source, and wherein said article comprises a printed circuit board mounted on said table so as to allow selected portions of said circuit board to be positioned within the focused and reflected light-receiving range of said camera, and wherein said surface areas on the printed circuit board having a substantially smooth, planar two-dimensional profile selectively comprise patterned circuit paths and terminals, which paths and terminals appear as dark gray areas on the screen of said monitor when operated in a black and white mode, whereas said surface areas having a contoured three-dimensional profile, such as satisfactory soldered fillets, any abnormal solder bridges and icicles appearing randomly, and any scratches and pits in said normally smooth planar profiled surface areas, selectively and respectively appear as discrete, bright areas on said monitor screen.
Claim 25
Dependent Claim
148 words
A video system in accordance with claim 21 further comprising: an indexable table mounted beneath said light source, and wherein said article comprises a printed circuit board mounted on said table so as to allow selected portions of said circuit board to be positioned within the focused and reflected light-receiving range of said camera, and wherein said surface areas on the printed circuit board having a substantially smooth, planar two-dimensional profile selectively comprise patterned circuit paths and terminals, which paths and terminals appear as dark gray areas on the screen of said monitor when operated in a black and white mode, whereas said surface areas having a contoured three-dimensional profile, such as satisfactory soldered fillets, any abnormal solder bridges and icicles appearing randomly, and any scratches and pits in said normally smooth planar profiled surface areas, selectively and respectively appear as discrete, bright areas on said monitor screen.
Claim 26
Independent Claim
197 words
A method of discriminating between two-dimensional and three-dimensional light-reflective patterned surface areas formed on an exposed surface of an article, said method comprising the steps of: illuminating the exposed surface of said article with polarized light that extends across said surface such that in a direction at least substantially perpendicular thereto: (1) reflected light is minimized from those light-reflective areas on said patterned surfaces having a substantially smooth, two-dimensional profile, and (2) reflected light is maximized from those light-reflective areas on said surface having a three-dimensional profile; positioning a video camera above the exposed surface of the article, with the axis of the camera lens being oriented substantially perpendicularly to both the exposed surface and the light ray paths of said polarized light, for receiving the minimized and maximized patterns of reflected light from said respectively different types of surface areas, and for generating video signals, when energized, that are of the type to produce contrasting patterns representative of said respectively different types of surface areas on the screen of a video monitor, and connecting a video monitor to the camera, energizing said monitor, and applying said video signals thereto so as to produce said contrasting patterns.
Claim 27
Independent Claim
197 words
A method of discriminating between two-dimensional and three-dimensional light-reflective patterned surface areas formed on an exposed surface of an article, said method comprising the steps of: illuminating the exposed surface of said article with polarized light that extends across said surface such that in a direction at least substantially perpendicular thereto: (1) reflected light is minimized from those light-reflective areas on said patterned surfaces having a substantially smooth, two-dimensional profile, and (2) reflected light is maximized from those light-reflective areas on said surface having a three-dimensional profile; positioning a video camera above the exposed surface of the article, with the axis of the camera lens being oriented substantially perpendicularly to both the exposed surface and the light ray paths of said polarized light, for receiving the minimized and maximized patterns of reflected light from said respectively different types of surface areas, and for generating video signals, when energized, that are of the type to produce contrasting patterns representative of said respectively different types of surface areas on the screen of a video monitor, and connecting a video monitor to the camera, energizing said monitor, and applying said video signals thereto so as to produce said contrasting patterns.
Claim 28
Dependent Claim
96 words
A method in accordance with claim 24 further comprising the steps of: highlighting any region of a light-reflective surface area on the exposed article surface having a three-dimensional profile, and within the focused range of the camera, by interposing a polarized lens between said camera and the exposed surface of said article, and gradually rotating said polarized lens until the maximum amount of reflected light from any given three-dimensional surface area region is received by said camera, and converted in said camera and monitor into a vivid, brightly illuminated area on the screen of the latter.
Claim 29
Dependent Claim
115 words
A method in accordance with claim 25 further comprising the steps of: selectively displacing the article surface to be examined along an X-Y coordinate plane relative to the camera so as to allow magnified, predetermined sectionalized areas thereof to be examined and, thereby, displayed with greater resolution on the screen of said monitor; and selectively changing the spacing between the exposed article surface and the camera so as to selectively adjust the focus of said camera and to allow for a suitable marking to be made on the exposed surface of the article adjacent any two-dimensional or three-dimensional area thereof that appears on the monitor with an abnormal degree of brightness indicative of a defect.
Claim 30
Dependent Claim
53 words
A method in accordance with claim 26 further comprising the step of: comparing a pre-formed standard composite reference pattern against the monitor-displayed contrasting patterns, representative of the camera-viewed composite pattern on the surface of said article, so as to readily ascertain all correspondingly similar patterned areas, as well as any dissimilar patterned areas.
Claim 31
Dependent Claim
92 words
A method in accordance with claim 26 further comprising the steps of: picking up successively under vacuum control colored marking dots of suitable material from a dot-carrying support; transferring said dots respectively to each area on said exposed article surface that is identified on said monitor as exhibiting particular light-reflective characteristics that make such an area of interest thereafter in the subsequent use of said article, and depositing each picked-up dot adjacent a different one of said areas of particular interest by adjusting the magnitude of the vacuum applied against said dot.
Claim 32
Independent Claim
112 words
A method of detecting a projection extending from a reference surface, wherein the projection has a reflecting surface that extends at least in part in a non-orthogonal direction toward said reference surface, which comprises the steps of: projecting an annular array of polarized light rays toward said projection, with said polarized light rays being oriented in vertical and radially extending planes with respect to said reference surface, to reflect certain of said polarized light rays from said reflecting surface; and generating a light image from at least a portion of the light rays of said polarized array thereof that are reflected, whereby said reflecting surface is readily discernable in said light image.
Claim 33
Independent Claim
112 words
A method of detecting a projection extending from a reference surface, wherein the projection has a reflecting surface that extends at least in part in a non-orthogonal direction toward said reference surface, which comprises the steps of: projecting an annular array of polarized light rays toward said projection, with said polarized light rays being oriented in vertical and radially extending planes with respect to said reference surface, to reflect certain of said polarized light rays from said reflecting surface; and generating a light image from at least a portion of the light rays of said polarized array thereof that are reflected, whereby said reflecting surface is readily discernable in said light image.
References Cited (Backward Citations)
US3713741A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-06 | 1980-12-06 | 1981-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-06 | 1984-12-06 | 1985-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-06 | 1988-12-06 | 1989-06-07 | $7700.00 | Window Closed / Lapsed |