US4291938A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for dark field illumination
Assignee: International Business Machines Corp
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Filing: 1979-11-30
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Granted: 1981-09-29
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Expires: 1999-11-30
Abstract
Abstract Apparatus for dark field illumination consisting of light conducting fibers having end faces arranged within an annular region which is coaxial with the optical axis of an optical assembly, such as a microscope objective. The annular region is within the numerical aperture of the optical assembly and is positioned in the rear focal plane thereof so that light emitted by the fibers becomes dark field illumination for the object plane of the optical assembly when viewed through the central aperture of the annular region. Illumination of the object plane through the central aperture also dark field illuminates the object plane when viewed through the fibers. This is true even when the object plane is illuminated in only a small area by forcussing an illumination source through the central aperture and onto the object plane.
Inventors
- 👤 Dietmar Wagner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:11
CPC Classifications
G; G02; G02B; G02B21/00; G02B21/06; G02B21/08; G02B21/10
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
120 words
Dark field illumination apparatus comprising: an optical assembly defining a focal plane on one side thereof and having an object plane on the other side thereof; means dividing the portion of said focal plane which is within the numerical aperture of said optical assembly into an annular region coaxial with the optical axis of said optical assembly and a central aperture region surrounded by said annular region; a plurality of light conducting fibers each having one end face disposed within said annular region and directed toward said optical assembly; and means for illuminating the other end faces of said light conductors, said object plane being dark field illuminated thereby when viewed through said central aperture region of said focal plane.
Claim 2
Dependent Claim
120 words
Dark field illumination apparatus comprising: an optical assembly defining a focal plane on one side thereof and having an object plane on the other side thereof; means dividing the portion of said focal plane which is within the numerical aperture of said optical assembly into an annular region coaxial with the optical axis of said optical assembly and a central aperture region surrounded by said annular region; a plurality of light conducting fibers each having one end face disposed within said annular region and directed toward said optical assembly; and means for illuminating the other end faces of said light conductors, said object plane being dark field illuminated thereby when viewed through said central aperture region of said focal plane.
Claim 3
Dependent Claim
17 words
Dark field illumination apparatus as defined in claim 1 wherein said optical assembly is a lens assembly.
Claim 4
Dependent Claim
19 words
Dark field illumination apparatus as defined in claim 2 wherein said lens assembly consists of a single lens element.
Claim 5
Dependent Claim
19 words
Dark field illumination apparatus as defined in claim 1 wherein said optical assembly is an objective of a microscope.
Claim 6
Dependent Claim
25 words
Dark field illumination apparatus as defined in claim 1 wherein said object plane is in the vicinity of a focal plane of said optical element.
Claim 7
Dependent Claim
125 words
Dark field illumination apparatus comprising: an optical assembly defining a focal plane on one side thereof and having an object plane on the other side thereof; means dividing the portion of said focal plane which is within the numerical aperture of said optical assembly into an annular region coaxial with the optical axis of said optical assembly and a central aperture region surrounded by said annular region; a plurality of light conducting fibers each having one end face disposed within said annular region and directed toward said optical assembly; and means for illuminating at least a portion of said object plane through said central aperture region of said focal plane, said object plane being dark field illuminated thereby when viewed through said light conducting fibers.
Claim 8
Dependent Claim
125 words
Dark field illumination apparatus comprising: an optical assembly defining a focal plane on one side thereof and having an object plane on the other side thereof; means dividing the portion of said focal plane which is within the numerical aperture of said optical assembly into an annular region coaxial with the optical axis of said optical assembly and a central aperture region surrounded by said annular region; a plurality of light conducting fibers each having one end face disposed within said annular region and directed toward said optical assembly; and means for illuminating at least a portion of said object plane through said central aperture region of said focal plane, said object plane being dark field illuminated thereby when viewed through said light conducting fibers.
Claim 9
Dependent Claim
17 words
Dark field illumination apparatus as defined in claim 6 wherein said optical assembly is a lens assembly.
Claim 10
Dependent Claim
19 words
Dark field illumination apparatus as defined in claim 7 wherein said lens assembly consists of a single lens element.
Claim 11
Dependent Claim
25 words
Dark field illumination apparatus as defined in claim 6 wherein said object plane is in the vicinity of a focal plane of said optical element.
Claim 12
Dependent Claim
24 words
Dark field illumination apparatus as defined in claim 6 wherein only a small spot region of said object plane is illuminated at one time.
Claim 13
Dependent Claim
26 words
Dark field illumination apparatus as defined in claim 10 and further comprising means for varying the position in said object plane of said illuminated spot region.
Claim 14
Dependent Claim
37 words
Dark field illumination apparatus as defined in claim 6 wherein said means for illuminating comprises means for causing illumination light coming through said central aperture region to become focussed to a small spot at said object plane.
Claim 15
Dependent Claim
37 words
Dark field illumination apparatus as defined in claim 6 wherein said means for illuminating comprises a point-like source of light and means for imaging said point-like source through said central aperture region and onto said object plane.
Claim 16
Dependent Claim
33 words
Dark field illumination apparatus as defined in claim 6 and further comprising means for varying the position of the image of said point-like source with respect to an object in said object plane.
Claim 17
Dependent Claim
43 words
Dark field illumination apparatus as defined in claim 14 wherein said means for varying the position of the image of said point-like source with respect to the object in said object plane includes means for physically moving said object within said object plane.
References Cited (Backward Citations)
DE34024C
Cited
DE488899C
Cited
DE1622989U
Cited
FR1405241A
Cited
FR2036206A5
Cited
DE2211702A1
Cited
GB1394743A
Cited
DE2301597A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-09-28 | 1985-03-30 | 1985-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-28 | 1989-03-30 | 1989-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-28 | 1993-03-30 | 1993-09-29 | $7700.00 | Window Closed / Lapsed |