Patent US3737665A successfully refreshed from Google Patents.
US3737665A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for automatically detecting defects and irregularities in glass sheet
Assignee: Central Glass Co Ltd
•
Filing: 1971-10-20
•
Granted: 1973-06-05
•
Expires: 1991-10-20
Abstract
Abstract Method for automatically detecting defects and irregularities contained in or on the surface of glass sheet. The method includes scanning laser beams on the glass sheet and with a laser detector, detecting the presence of defects by measuring the decrease of light input reaching the laser detector as a result of dispersion of the laser beam by the defects. Apparatus for carrying out method.
Inventors
- 👤 Y Nagae
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 00:53
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/89; G01N21/892; G01N21/896
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
184 words
Apparatus for detecting irregularities contained in glass sheet, comprising laser beam projecting means mounted adjacent to and substantially aligned with one longitudinal edge of said glass sheet for directing a laser beam transversely across a longitudinally moving elongated sheet of glass from a point beyond one longitudinal edge of said sheet in the direction of the width of said sheet, means for periodically oscillating said beam about said point in an acute arc to scan the whole width of said sheet, said beam intersecting said sheet at an acute angle over the whole width of said sheet as it moves from one edge of the sheet to the other, receiving means fixedly positioned alongside the opposite longitudinal edge of said sheet for receiving a portion of said beam from said sheet during said scanning to generate a signal corresponding to the intensity of said beam and detection circuit means connected to receive said receiving means output signal for detecting variations in the amplitude thereof with respect to a predetermined level during each said scan and for issuing a defect signal indicative of said variations.
Claim 2
Dependent Claim
184 words
Apparatus for detecting irregularities contained in glass sheet, comprising laser beam projecting means mounted adjacent to and substantially aligned with one longitudinal edge of said glass sheet for directing a laser beam transversely across a longitudinally moving elongated sheet of glass from a point beyond one longitudinal edge of said sheet in the direction of the width of said sheet, means for periodically oscillating said beam about said point in an acute arc to scan the whole width of said sheet, said beam intersecting said sheet at an acute angle over the whole width of said sheet as it moves from one edge of the sheet to the other, receiving means fixedly positioned alongside the opposite longitudinal edge of said sheet for receiving a portion of said beam from said sheet during said scanning to generate a signal corresponding to the intensity of said beam and detection circuit means connected to receive said receiving means output signal for detecting variations in the amplitude thereof with respect to a predetermined level during each said scan and for issuing a defect signal indicative of said variations.
Claim 3
Dependent Claim
44 words
The apparatus of claim 1, wherein the point from which said beam is directed across such sheet is spaced from the plane of said sheet such that said beam is projected during scanning in a direction nearly parallel to the width of said sheet.
Claim 4
Dependent Claim
24 words
The apparatus of claim 2, wherein said beam intersects said sheet at approximately the same acute angle over the whole width of said sheet.
Claim 5
Dependent Claim
41 words
The detecting apparatus according to claim 1, wherein said laser beam projecting means includes a laser oscillator for generating a laser beam and at least one oscillating mirror operatively aligned with said laser oscillator for deflecting said laser toward said sheet.
Claim 6
Dependent Claim
38 words
The detecting apparatus according to claim 1, wHerein said laser beam projecting means includes a laser oscillator for generating a laser beam and a polyhedral rotary mirror mounted for rotation to deflect said laser beam toward said sheet.
Claim 7
Dependent Claim
42 words
The detecting apparatus according to claim 1, wherein said laser projecting means is spaced obliquely from said one edge of said sheet such that during said scanning said beam is incident on said sheet at an acute angle to the surface thereof.
Claim 8
Dependent Claim
35 words
The detecting apparatus according to claim 1, wherein said light beam receiving means includes a fiber optic element and a photoelectric converter for receiving the light from said beam conducted by said fiber optic element.
Claim 9
Dependent Claim
35 words
The apparatus of claim 7, wherein said fiber-optic element has a receiving end which is disposed adjacent to said opposite edge to subtend the arc swept out by said beam during scanning of said sheet.
Claim 10
Dependent Claim
21 words
The apparatus of claim 8, wherein the length of said receiving end is substantially less than the width of said sheet.
Claim 11
Dependent Claim
80 words
The detecting apparatus according to claim 1, wherein said detection circuit means includes a discriminator circuit operatively receiving the output of said light receiving means for comparison thereof with a predetermined signal level, said discriminator circuit generating an output pulse when said predetermined signal level exceeds said light receiving means output during each said scan, and an output circuit connected to be energized by said discriminator circuit output pulse for generating a defect signal for a predetermined period of time.
Claim 12
Dependent Claim
165 words
Apparatus for detecting defects and irregularities contained in glass sheet drawn from a melting furnace and transferred via at least one pair of opposing take-up rolls, comprising laser beam projecting means mounted adjacent to one longitudinal edge of said glass sheet between said melting furnace and a first pair of said take-up rolls for projecting a laser beam into the surface of said sheet during transfer thereof and repeatedly scanning said beam across the surface of said sheet, laser beam receiving means operatively mounted adjacent the other longitudinal edge of said sheet between said melting furnace and said first pair of take-up rolls to receive a portion of the light in said beam from said sheet surface during said scanning for generating a signal corresponding to the intensity of the light thus received, and a detection circuit operatively connected to said receiving means for detecting variations of the amplitude of said receiving means output signal and for issuing a defect signal indicative of said variations.
Claim 13
Dependent Claim
165 words
Apparatus for detecting defects and irregularities contained in glass sheet drawn from a melting furnace and transferred via at least one pair of opposing take-up rolls, comprising laser beam projecting means mounted adjacent to one longitudinal edge of said glass sheet between said melting furnace and a first pair of said take-up rolls for projecting a laser beam into the surface of said sheet during transfer thereof and repeatedly scanning said beam across the surface of said sheet, laser beam receiving means operatively mounted adjacent the other longitudinal edge of said sheet between said melting furnace and said first pair of take-up rolls to receive a portion of the light in said beam from said sheet surface during said scanning for generating a signal corresponding to the intensity of the light thus received, and a detection circuit operatively connected to said receiving means for detecting variations of the amplitude of said receiving means output signal and for issuing a defect signal indicative of said variations.
Claim 14
Dependent Claim
63 words
The apparatus of claim 11, wherein said beam projecting means includes means for directing said beam transversely across said sheet from a point beyond said one edge in the direction of the width of said sheet and spaced from the plane of said sheet such that said beam is projected during scanning in a direction nearly parallel to the width of said sheet.
Claim 15
Dependent Claim
11 words
The apparatus of claim 11, wherein said receiving means is stationary.
Claim 16
Dependent Claim
46 words
The apparatus of claim 11, wherein said receiving means includes a fiber-optic element having a receiving end fixedly positioned to subtend the arc swept out by said beam during scanning and a photoelectric converter for receiving the light from said beam conducted by said fiber-optic element.
Claim 17
Dependent Claim
25 words
The apparatus of claim 14, wherein the length of said receiving end of said fiber-optic element is substantially less than the width of said sheet.
Claim 18
Independent Claim
143 words
A method of automatically detecting defects and irregularities contained in glass sheet, comprising the steps of directing a laser beam transversely across a longitudinally moving elongated sheet of glass from a point substantially aligned with and beyond one longitudinal edge of said sheet in the direction of the width of said sheet, periodically oscillating said beam about said point in an acute arc to scan the whole width of said sheet, said beam intersecting said sheet at an acute angle over the whole width of said shEet as it moves from one edge of the sheet to the other, receiving at a stationary location along the opposite edge of said sheet a portion of said laser beam from said sheet during said scanning, and continuously detecting the presence and absence of irregularities in said sheet from variations of intensity of the received beam.
Claim 19
Independent Claim
143 words
A method of automatically detecting defects and irregularities contained in glass sheet, comprising the steps of directing a laser beam transversely across a longitudinally moving elongated sheet of glass from a point substantially aligned with and beyond one longitudinal edge of said sheet in the direction of the width of said sheet, periodically oscillating said beam about said point in an acute arc to scan the whole width of said sheet, said beam intersecting said sheet at an acute angle over the whole width of said shEet as it moves from one edge of the sheet to the other, receiving at a stationary location along the opposite edge of said sheet a portion of said laser beam from said sheet during said scanning, and continuously detecting the presence and absence of irregularities in said sheet from variations of intensity of the received beam.
Claim 20
Dependent Claim
24 words
The method of claim 16, wherein said beam is projected across said sheet in a direction nearly parallel to the width of said sheet.
Claim 21
Dependent Claim
24 words
The method of claim 17, wherein said beam intersects said sheet at approximately the same acute angle over the whole width of said sheet.
Claim 22
Dependent Claim
31 words
The method of claim 16, wherein the step of receiving a portion of said beam from said sheet includes receiving the portion of said beam transmitted through said sheet during scanning.
Claim 23
Dependent Claim
35 words
The method of claim 16, wherein the step of receiving the portion of said beam from said sheet includes receiving the portion of said beam reflected from the surface of said sheet during said scanning.
Claim 24
Dependent Claim
22 words
The method of claim 16, further comprising the step of detecting the time within each scanning period at which said variations occur.
Claim 25
Dependent Claim
35 words
The method of claim 16, wherein said point is spaced from the plane of said sheet such that said beam is projected in a direction nearly parallel to the width of said sheet during scanning.
References Cited (Backward Citations)
US2993402A
Cited
US3199401A
Cited
US3174046A
Cited
US3188478A
Cited
US3524988A
Cited
US3510664A
Cited
US3612702A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |