Patent US4040748A successfully refreshed from Google Patents.
US4040748A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inspection tool
Assignee: International Business Machines Corp
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Filing: 1976-03-25
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Granted: 1977-08-09
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Expires: 1996-03-25
Abstract
Abstract This patent discloses an improved inspection tool for rapidly inspecting miniature electronic conductor patterns, circuits and the like. The tool focuses a laser beam to a small laser spot that raster scans a large conductor pattern area on the workpiece being inspected. Reflected laser light from the workpiece impinges upon a light detector that generates electrical signals according to the presence or absence of conductor pattern material on the workpiece at the momentary X and Y coordinate of the scanning laser spot. The light detector signals are compared with a previously encoded data image of the correct circuit pattern for the X and Y coordinates of the scanning laser spot. When the signals and the data agree at all X and Y coordinate points the workpiece is accepted. If the signals and the data do not agree at one or more X and Y coordinate points a defect in the circuit pattern is indicated. A defect may indicate out-of-tolerance dimensions, possible electrical short circuits, and/or open circuits. The extent of a defect may be determined by adjacent X and Y coordinate points and suitable computer programming, while workpieces having extended or out-of-tolerance defects are rejected. The improved disclosed inspection tool includes apparatus for automatically compensating for variations in the workpieces, and to effect registration for the scanning laser spot.
Inventors
- 👤 James Garman Belleson
- 👤 Kendall Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:17
CPC Classifications
G; G07; G07C; G07C3/00; G07C3/14; G01; G01B; G01B11/00; G01B11/002; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/89; G01N21/892; G01N21/898; G01R; G01R31/00; G01R31/26; G01R31/265; G01R31/2656; G01R31/28; G01R31/302; G01R31/308; G01R31/309; G01N21/95; G01N21/956
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
238 words
An inspection tool comprising: means to position a workpiece in a work zone, said workpiece having a pattern to be inspected; a source of coherent light and means to effect a sweep of said coherent light across said work zone; first light detector means positioned adjacent said work zone to receive light reflected from said workpiece from said sweep of coherent light; a grating having a plurality of interdigitated light receiving and light transmitting lines thereon; means to reflect at least a portion of said coherent light onto said grating to intercept said lines on said grating at an oblique angle; second light detector means positioned to receive light transmitted by said light transmitting lines of said grating so that the position of said sweep of coherent light across said work zone may be determined; means to adjust the angle of said coherent light interception of said lines on said grating responsive to the light received by said first and second light detector means as compared with the position of a pattern on a nominal workpiece; means to provide relative movement between said workpiece and said sweep of coherent light across said work zone in a path substantially perpendicular to said sweep of coherent light; and means interconnecting the means to provide relative movement and said means to effect said sweep for synchronizing said sweep of coherent light to said relative movement of a workpiece in said path.
Claim 2
Dependent Claim
238 words
An inspection tool comprising: means to position a workpiece in a work zone, said workpiece having a pattern to be inspected; a source of coherent light and means to effect a sweep of said coherent light across said work zone; first light detector means positioned adjacent said work zone to receive light reflected from said workpiece from said sweep of coherent light; a grating having a plurality of interdigitated light receiving and light transmitting lines thereon; means to reflect at least a portion of said coherent light onto said grating to intercept said lines on said grating at an oblique angle; second light detector means positioned to receive light transmitted by said light transmitting lines of said grating so that the position of said sweep of coherent light across said work zone may be determined; means to adjust the angle of said coherent light interception of said lines on said grating responsive to the light received by said first and second light detector means as compared with the position of a pattern on a nominal workpiece; means to provide relative movement between said workpiece and said sweep of coherent light across said work zone in a path substantially perpendicular to said sweep of coherent light; and means interconnecting the means to provide relative movement and said means to effect said sweep for synchronizing said sweep of coherent light to said relative movement of a workpiece in said path.
Claim 3
Dependent Claim
25 words
An inspection tool in accordance with claim 1 wherein said light transmitting lines on said grating are transparent and said light receiving lines are opaque.
Claim 4
Dependent Claim
57 words
An inspection tool in accordance with claim 2 wherein said lines on said grating are positioned at an oblique angle relative to said reflected portion of said sweep of coherent light, and lens means intermediate said grating and said second light detector means for focussing the light passing through said grating onto said second light detector means.
Claim 5
Dependent Claim
34 words
An inspection tool in accordance with claim 3 including frame means mounting said grating for rotation about a pivot point, and grating actuator means connected to said frame for effecting rotation of said grating.
Claim 6
Dependent Claim
46 words
An inspection tool in accordance with claim 3 including a frame; a sub-frame interiorly of said frame and mounting said grating; actuator means interconnecting said sub-frame and said frame to effect changes in the position of said sub-frame and thus said grating relative to said frame.
Claim 7
Dependent Claim
28 words
An inspection tool in accordance with claim 5 including means to support said frame for rotation about a pivot point, and second actuator means for effecting said rotation.
Claim 8
Dependent Claim
47 words
An inspection tool in accordance with claim 3 including counter means connected to said second light detector means so that as the sweep of reflected light is transmitted by said light transmitting lines, said second light detector means receives pulses of light for counting by said counter.
Claim 9
Dependent Claim
56 words
An inspection tool in accordance with claim 7 including comparing means connected to said counter, means for connecting said first light detector means to said comparing means, and means for comparing the light received from a workpiece at a predetermined coordinate thereon to the light that should be received from a nominal workpiece at that coordinate.
Claim 10
Dependent Claim
51 words
An inspection tool in accordance with claim 8 wherein said means to provide relative movement between a workpiece and said sweep of coherent light comprises a cylinder mounted for rotation, and said means to position a workpiece in said work zone comprises means carried by said cylinder for gripping a workpiece.
Claim 11
Dependent Claim
58 words
An inspection tool in accordance with claim 9 wherein said means to effect a sweep of said coherent light across said work zone comprises a mirror; means supporting said mirror for rotation in the intended path of the beam of coherent light from said source of coherent light, and first drive means for effecting rotation of said mirror.
Claim 12
Dependent Claim
44 words
An inspection tool in accordance with claim 10 wherein said means interconnecting said means to effect a sweep for synchronizing said sweep to said relative movement of a workpiece in said path comprises a gear train interconnecting said first drive means to said cylinder.
Claim 13
Dependent Claim
39 words
An inspection tool in accordance with claim 11 including a differential gear means in said gear train, and second drive means connected to said differential gear means whereby variations in the rotational speed of said cylinder may be obtained.
Claim 14
Dependent Claim
30 words
An inspection tool in accordance with claim 12 including means to actuate said second drive means responsive to differences in the length of a workpiece relative to a nominal workpiece.
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) | 1980-08-08 | 1981-02-07 | 1981-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-08 | 1985-02-07 | 1985-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-08 | 1989-02-07 | 1989-08-09 | $7700.00 | Window Closed / Lapsed |