Patent US3877814A successfully refreshed from Google Patents.
US3877814A
Expired / Lapsed
US
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Method of and apparatus for detecting concave and convex portions in a specular surface
Assignee: PPG Industries Inc
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Filing: 1973-02-07
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Granted: 1975-04-15
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Expires: 1993-02-07
Abstract
Abstract A method of and apparatus for detecting concave and convex portions in a surface of a glass ribbon are disclosed. A collimated beam of light is directed toward a top surface of the glass ribbon at a preselected angle of incidence to minimize reflections from the bottom surface. A photo sensing detector is displaced across the glass ribbon along the path of the collimated beam to sense changes in intensity of reflected beams from the top surface. Concave and convex portions in the top surface increase and decrease the intensity of the reflected beams, respectively, as compared to beams reflected from flat portions on the surface. By observing the intensity of the reflected beams, concave and convex portions in the surface can be determined.
Inventors
- 👤 Daniel J Hess
- 👤 Robert J Obenreder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 02:31
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/89; G01N21/892; G01N21/896
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
262 words
A Method of sensing concave and convex portions in a first surface of a piece of glass, wherein the piece of glass has a second surface opposite to the first surface, comprising the steps of: directing a collimated beam of light toward the piece of glass at an oblique angle of incidence selected (1) to reflect beams of light from the first surface of the piece of glass as first reflected beams of light; (2) to transmit beams of light through the piece of glass to reflect beams of light from the second surface through the first surface as second reflected beams of light; and (3) to enhance the intensity variations of the first reflected beams of light reflected from concave and convex portions in the first surface of the piece of glass; intercepting the first and second reflected beams of light by photosensing means positioned at a distance from the first surface approximately equal to or less than the focal length, at the selected oblique angle of incidence, of the smallest expected radii of curvature of concave portions in the first surface to differentiate between diverging beams of light from convex portions and converging beams of light from concave portions in the first surface of the piece of glass; and providing relative motion between the piece of glass and the photosensing means to monitor intensity variations of the first and second reflected beams of light wherein intensity variations sensed by the photosensing means are primarily a function of concave and convex portions in the first surface of the piece of glass.
Claim 2
Independent Claim
262 words
A Method of sensing concave and convex portions in a first surface of a piece of glass, wherein the piece of glass has a second surface opposite to the first surface, comprising the steps of: directing a collimated beam of light toward the piece of glass at an oblique angle of incidence selected (1) to reflect beams of light from the first surface of the piece of glass as first reflected beams of light; (2) to transmit beams of light through the piece of glass to reflect beams of light from the second surface through the first surface as second reflected beams of light; and (3) to enhance the intensity variations of the first reflected beams of light reflected from concave and convex portions in the first surface of the piece of glass; intercepting the first and second reflected beams of light by photosensing means positioned at a distance from the first surface approximately equal to or less than the focal length, at the selected oblique angle of incidence, of the smallest expected radii of curvature of concave portions in the first surface to differentiate between diverging beams of light from convex portions and converging beams of light from concave portions in the first surface of the piece of glass; and providing relative motion between the piece of glass and the photosensing means to monitor intensity variations of the first and second reflected beams of light wherein intensity variations sensed by the photosensing means are primarily a function of concave and convex portions in the first surface of the piece of glass.
Claim 3
Dependent Claim
54 words
The method as set forth in claim 1, wherein the angle of incidence of the collimated beam is selected such that the ratio of the fraction of incident energy of the second reflected beams of light to the fraction of incident energy of the first reflected beams of light is between 0 and 0.21.
Claim 4
Independent Claim
248 words
An apparatus for sensing concave and convex portions in a first surface of a piece of glass wherein the piece of glass has a second surface opposite to the first surface comprising: means for directing a collimated beam of light at an oblique angle of incidence selected (1) to reflect beams of light from the first surface of the piece of glass as first reflected beams of light; (2) to transmit beams of light through the piece of glass to reflect beams of light from the second surface through the first surface as second reflected beams of light; and (3) to enhance the intensity variations of the first reflected beams of light reflected from concave and convex portions in the first surface of the piece of glass; photosensing means for monitoring the intensity variations of the first and second reflected beams of light mounted in the path of the first and second reflected beams of light at a distance from the first surface approximately equal to or less than the focal length, at the oblique angle of incidence, of the smallest expected radii of curvature of concave portions in the first surface wherein intensity variations sensed by photosensing means are primarily a function of concave and convex portions in the first surface of the piece of glass; and means for displacing the piece of glass and said photosensing means relative to one another to sense concave and convex portions in the first surface of the piece of glass.
Claim 5
Independent Claim
248 words
An apparatus for sensing concave and convex portions in a first surface of a piece of glass wherein the piece of glass has a second surface opposite to the first surface comprising: means for directing a collimated beam of light at an oblique angle of incidence selected (1) to reflect beams of light from the first surface of the piece of glass as first reflected beams of light; (2) to transmit beams of light through the piece of glass to reflect beams of light from the second surface through the first surface as second reflected beams of light; and (3) to enhance the intensity variations of the first reflected beams of light reflected from concave and convex portions in the first surface of the piece of glass; photosensing means for monitoring the intensity variations of the first and second reflected beams of light mounted in the path of the first and second reflected beams of light at a distance from the first surface approximately equal to or less than the focal length, at the oblique angle of incidence, of the smallest expected radii of curvature of concave portions in the first surface wherein intensity variations sensed by photosensing means are primarily a function of concave and convex portions in the first surface of the piece of glass; and means for displacing the piece of glass and said photosensing means relative to one another to sense concave and convex portions in the first surface of the piece of glass.
Claim 6
Dependent Claim
53 words
The apparatus as set forth in claim 3, wherein said directing means positions the collimated beam of light such that the ratio of the fraction of incident energy of the second reflected beams of light to the fraction of incident energy of the first reflected beams of light is between 0 and 0.21.
Claim 7
Dependent Claim
25 words
The apparatus as set forth in claim 3 including: means acted on by said photosensing means for recording intensity of the reflected beams of light.
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) | 1978-04-14 | 1978-10-14 | 1979-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-14 | 1982-10-14 | 1983-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-14 | 1986-10-14 | 1987-04-15 | $7700.00 | Window Closed / Lapsed |