US4447152A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for detecting defects in apertured plates
Assignee: International Business Machines Corp
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Filing: 1981-12-24
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Granted: 1984-05-08
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Expires: 2001-12-24
Abstract
Abstract A method and apparatus for detecting defects in apertures plates such as masks. The plate is illuminated by a collimated light beam and defects or irregularities are signalled by a bright spot of light. A modified microfilm reader or the like can be used to magnify and project an image of that portion of the plate associated with the bright spot of light.
Inventors
- 👤 Robert E. Rainford
- 👤 Mark M. Moser
- 👤 Jon R. Ojala
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:45
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/8803
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
72 words
The method of inspecting an apertured plate comprising: directing an intense polychromatic collimated light beam perpendicular to a major dimension of said plate and parallel to axes of apertures therethrough, viewing the beam passing through the apertures at an angle of between 30° and 60° to the plane of a major dimension of the plate, whereby defects or irregularities in the plate or said apertures result in one or more bright spots.
Claim 2
Independent Claim
72 words
The method of inspecting an apertured plate comprising: directing an intense polychromatic collimated light beam perpendicular to a major dimension of said plate and parallel to axes of apertures therethrough, viewing the beam passing through the apertures at an angle of between 30° and 60° to the plane of a major dimension of the plate, whereby defects or irregularities in the plate or said apertures result in one or more bright spots.
Claim 3
Dependent Claim
32 words
The method of claim 1 which includes a further step of rotating said apertured plate through approximately 360° to observe each of the apertures with respect to said beam at said angle.
Claim 4
Independent Claim
52 words
The method of claims 1 or 2 which includes the further step of: locating at least one said bright spot, locating said apertured plate in a magnifying apparatus and magnififying a selected portion of said plate in the vicinity of said bright spot to produce a magnified image of said selected portion.
Claim 5
Dependent Claim
15 words
The method of claim 3 which further includes comparing said magnified image with a template.
Claim 6
Dependent Claim
28 words
The method of claim 1 or 2 which includes the further step of directing a jet of cleaning fluid at apertures in the vicinity of said bright spot.
Claim 7
Dependent Claim
79 words
An inspection apparatus for inspecting apertured plates comprising: an intense polychromatic light source, collimating means for collimating light emitted from the source and forming a collimated light beam having a designated path, and support means for supporting said apertured plate in the path of and substantially perpendicular to said beam so as to allow said mask to be viewed from a relatively fixed observation location with the mark in at least two different positions relative to said observation location.
Claim 8
Dependent Claim
79 words
An inspection apparatus for inspecting apertured plates comprising: an intense polychromatic light source, collimating means for collimating light emitted from the source and forming a collimated light beam having a designated path, and support means for supporting said apertured plate in the path of and substantially perpendicular to said beam so as to allow said mask to be viewed from a relatively fixed observation location with the mark in at least two different positions relative to said observation location.
Claim 9
Dependent Claim
23 words
The apparatus of claim 6 which further includes projection means for enlarging and projecting the image of a selected portion of said plate.
Claim 10
Dependent Claim
36 words
The apparatus of claim 6 or 7 which further includes a source of a compressed fluid, and means for projecting a fluid jet through an aperture of said plate when contamination is observed in said aperture.
Claim 11
Dependent Claim
25 words
The apparatus of claim 7 which further includes a registering means for locating said apertured plate in a predetermined position relative to said projection means.
Claim 12
Dependent Claim
33 words
The apparatus of claim 9 in which said projection means comprises a projection screen and a viewing lens and said registering means comprises a pen and pointer fixed in relation to each other.
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) | 1987-05-08 | 1987-11-07 | 1988-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-08 | 1991-11-07 | 1992-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-08 | 1995-11-07 | 1996-05-08 | $7700.00 | Window Closed / Lapsed |