Patent US3976383A successfully refreshed from Google Patents.
US3976383A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Visual method of locating faults in printed circuit boards
Assignee: Bendix Corp
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Filing: 1975-02-28
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Granted: 1976-08-24
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Expires: 1995-02-28
Abstract
Abstract A method of visually detecting defects in a printed circuit board comprising preparing a mask with a light blocking pattern corresponding to the desired printed circuit, illuminating the printed circuit board through the mask with the light of a color complimentary to the color of the printed circuit board and with the light blocking pattern in registry with the printed circuit and inspecting the printed circuit board for light reflected from defects in the printed circuit not present in the light blocking pattern on the mask. The defects are readily apparent as bright spots on a dark background.
Inventors
- 👤 Oliver Albert Olsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:44
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/2801; G01R31/2806; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/8803; G01R31/302; G01R31/308; G01R31/309
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
90 words
A method of visually detecting defects in a printed circuit on a printed circuit board, comprising preparing a mask with a light blocking pattern corresponding to the desired printed circuit, illuminating the printed circuit board through the mask with a light of a color complimentary to the color of the printed circuit board and with the light blocking pattern in registry with the printed circuit, and inspecting the printed circuit board for light reflected from defects in the printed circuit not present in the light blocking pattern on the mask.
Claim 2
Independent Claim
90 words
A method of visually detecting defects in a printed circuit on a printed circuit board, comprising preparing a mask with a light blocking pattern corresponding to the desired printed circuit, illuminating the printed circuit board through the mask with a light of a color complimentary to the color of the printed circuit board and with the light blocking pattern in registry with the printed circuit, and inspecting the printed circuit board for light reflected from defects in the printed circuit not present in the light blocking pattern on the mask.
Claim 3
Dependent Claim
56 words
A method of visually detecting defects in a printed circuit on a printed circuit board as described in claim 1 in which the light blocking pattern on the mask has the same dimensions as the printed circuit and the mask is overlayed on the printed circuit board with the pattern in registry with the printed circuit.
Claim 4
Dependent Claim
47 words
A method of visually detecting defects in a printed circuit on a printed circuit board as described in claim 1 in which the light blocking pattern on the mask is projected by a projector and imaged on the printed circuit board in registry with the printed circuit.
Claim 5
Dependent Claim
48 words
A method of visually detecting defects in a printed circuit on a printed circuit board as described in claim 3 in which the circuit pattern on the mask is substantially smaller than the printed circuit and the projected pattern is enlarged to the size of the printed circuit.
Claim 6
Dependent Claim
41 words
A method of visually detecting defects in a printed circuit on a printed circuit board as described in claim 1 in which the mask is illuminated by white light and the mask filters the white light to provide the complimentary color.
Claim 7
Dependent Claim
42 words
The method of visually detecting defects in a printed circuit on a printed circuit board as described in claim 1 in which a source of white light is used and a separate filter filters the white light to provide the complimentary color.
Claim 8
Dependent Claim
32 words
A method of visually detecting defects in a printed circuit on a printed circuit board as described in claim 1 in which a source of light having a complimentary color is used.
References Cited (Backward Citations)
US3711205A
Cited
US3713741A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |