US3700909A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for detecting pinhole defects in foil material
Assignee: Columbia Research Corp
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Filing: 1972-03-09
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Granted: 1972-10-24
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Expires: 1992-03-09
Abstract
Abstract A system for detecting the number of pinhole defects in any given segment of advancing foil material. Particularly a narrow width ultra-violet light source and corresponding ultra-violet and photomultiplier unit, as well as associated circuitry for shaping and counting electrical pulses, corresponding to the diameter of the pinhole defects. The system distinguishes from the prior art in that it makes possible the detection of holes in a material having a large density of holes as well as discriminating as to the number of given defects in several different sizes or threshold categories.
Inventors
- 👤 Russell Murray
- 👤 Dominique Gignoux
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:47
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/89; G01N21/892; G01N21/894
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
142 words
Method for detecting pinhole defects in foil material comprising: A. advancing said foil through a detecting plane; B. directing an ultra-violet light source onto a restricted portion of said plane; said ultra-violet light being modulated at a frequency substantially exceeding that of commercial light frequency; C. filtering out non-ultra-violet light from beneath said advancing foil; D. laterally shielding an area after said filtering and receiving the beam of light transmitted through pinhole defects through said area and into photosensitive means to obtain electrical pulses, i. amplifying said pulses; ii. advancing said pulses past a pulse height analyzer, the height of said pulses being measured as proportional to the dimensions of the pinhole defects; iii. diverting pulse signals with respect to a series of height thresholds, and counting the number of defects at each threshold for a certain length oF advancing foil material.
Claim 2
Dependent Claim
142 words
Method for detecting pinhole defects in foil material comprising: A. advancing said foil through a detecting plane; B. directing an ultra-violet light source onto a restricted portion of said plane; said ultra-violet light being modulated at a frequency substantially exceeding that of commercial light frequency; C. filtering out non-ultra-violet light from beneath said advancing foil; D. laterally shielding an area after said filtering and receiving the beam of light transmitted through pinhole defects through said area and into photosensitive means to obtain electrical pulses, i. amplifying said pulses; ii. advancing said pulses past a pulse height analyzer, the height of said pulses being measured as proportional to the dimensions of the pinhole defects; iii. diverting pulse signals with respect to a series of height thresholds, and counting the number of defects at each threshold for a certain length oF advancing foil material.
Claim 3
Dependent Claim
28 words
Method for detecting pinhole defects in foil material as in claim 1, wherein said amplified electrical pulse is directed through an envelope detector, pulse shaper and driver means.
Claim 4
Dependent Claim
19 words
Method for detecting pinhole defects in foil material as in claim 1, wherein said photosensitive means are photomultiplier tubes.
Claim 5
Dependent Claim
21 words
Method for detecting pinhole defects in foil material as in claim 2, wherein said thresholds are representative of pinhole defects diameter.
Claim 6
Dependent Claim
33 words
Method for detecting pinhole defects in foil material as in claim 4, wherein said thresholds are respectively set to detect pinhole defects smaller than one of the following diameters: 0.005, 0.010 and 0.015.
Claim 7
Dependent Claim
38 words
Method for detecting pinhole defects in foil material as in claim 5, wherein detection is performed in a plurality of planes positioned around said advancing foil so as to sense defects in adjacent lineal portions of said foil.
Claim 8
Dependent Claim
33 words
System for detecting pinhole defects in foil material as in claim 5, including collimating ultra-violet light in a series of vertical channels such that said light strikes said foil material at right angles.
Claim 9
Dependent Claim
31 words
System for detecting pinhole defects in foil material as in claim 4, wherein said thresholds are respectively set to detect pinhole defects greater than the following diameters: 0.005, 0.010 and 0.015.
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) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |