US3847689A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming aperture plate for electron microscope
Assignee: National Aeronautics and Space Administration
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Filing: 1973-06-28
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Granted: 1974-11-12
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Expires: 1993-06-28
Abstract
Abstract An electron microscope including an electron source, a condenser lens having either a circular aperture for focusing a solid cone of electrons onto a specimen or an annular aperture for focusing a hollow cone of electrons onto the specimen, and an objective elns having an annular objective aperture, for focusing electrons passing through the specimen onto an image plane. The invention also entails a method of making the annular objective aperture using electron imaging, electrolytic deposition and ion etching techniques.
Inventors
- 👤 J Fletcher
- 👤 K Heinemann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:30
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J2237/00; H01J2237/04; H01J2237/045; H01J2237/0451; H01J2237/0453
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
129 words
A METHOD OF FORMING AN OBJECTIVE APERATURE PLATE FOR AN ELECTRON MICROSCOPE HAVING AN ANNULAR APERTURE, COMPRISING THE STEPS OF: DISPOSING AN ANNULAR APERTURE IN THE CONDENSER APERTURE PLANE TO FORM A HOLLOW CONE OF ELECTRONS; DIPOSING A FIRST METALLIC LAYER IN THE OBJECTIVE APERTURE PLANE OF THE FOCUSED MICROSCOPE AND IN THE PATH OF SAID ELECTRONS TO CAUSE A CONTAMINATION LAYER IN THE AREA MOLECULES TO FORM ON FIRST SAID METALLIC LAYER IN THE AREA ILLUMINATED BY SAID ELECTRONS; DISPOSING A SECOND METALLIC LAYER OVER THAT PORTION OF THE SURFACE OF THE FIRST METALLIC LAYER WHICH IS NOT COVERED BY THE CONTAMINATION LAYER; AND ETCHING THE COMPOSITE STRUCTURE ON THE SIDE OPPOSITE SAID SECOND METALLIC LAYER TO A DEPTH TRANSCENDING SAID FIRST METALLIC LAYER AND SAID CONTAMINATION LAYER.
Claim 2
Independent Claim
129 words
A METHOD OF FORMING AN OBJECTIVE APERATURE PLATE FOR AN ELECTRON MICROSCOPE HAVING AN ANNULAR APERTURE, COMPRISING THE STEPS OF: DISPOSING AN ANNULAR APERTURE IN THE CONDENSER APERTURE PLANE TO FORM A HOLLOW CONE OF ELECTRONS; DIPOSING A FIRST METALLIC LAYER IN THE OBJECTIVE APERTURE PLANE OF THE FOCUSED MICROSCOPE AND IN THE PATH OF SAID ELECTRONS TO CAUSE A CONTAMINATION LAYER IN THE AREA MOLECULES TO FORM ON FIRST SAID METALLIC LAYER IN THE AREA ILLUMINATED BY SAID ELECTRONS; DISPOSING A SECOND METALLIC LAYER OVER THAT PORTION OF THE SURFACE OF THE FIRST METALLIC LAYER WHICH IS NOT COVERED BY THE CONTAMINATION LAYER; AND ETCHING THE COMPOSITE STRUCTURE ON THE SIDE OPPOSITE SAID SECOND METALLIC LAYER TO A DEPTH TRANSCENDING SAID FIRST METALLIC LAYER AND SAID CONTAMINATION LAYER.
Claim 3
Dependent Claim
31 words
A method as recited in claim 1 and further comprising the step of evaporating a third metallic layer over said second metallic layer to add stability to the resultant aperture plate.
Claim 4
Dependent Claim
30 words
A method as recited in claim 1 wherein said first metallic layer is of silver and said second metallic layer is of copper galvanically grown over said first metallic layer.
Claim 5
Dependent Claim
33 words
A method as recited in claim 1 wherein said first metallic layer has a thickness of at least 300 A, and said second metallic layer has a thickness of at least 5,000 A.
Claim 6
Dependent Claim
25 words
A method as recited in claim 1 wherein said etching step is accomplished by bombarding said firSt metallic layer and said contamination layer with ions.
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) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |