US4414474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrector for axial aberrations in electron optic instruments
Assignee: University Patents Inc
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Filing: 1982-02-17
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Granted: 1983-11-08
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Expires: 2002-02-17
Abstract
Abstract Means for compensating for third and higher order aberrations in an electron optic system comprises two sextupoles and a field lens, the latter being spaced intermediate the sextupoles. The resolving power of the optic system can be reduced to the range of about 0.5 Angstrom unit.
Inventors
- 👤 Albert V. Crewe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:09
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/153
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
71 words
In an electron optic system, having a source of electrons, the improvement in the system for correction of third-order aberrations such that the point resolving power is reduced to less than 1.0 Angstrom unit, comprising: aligned first and second spaced sextupole means and an intermediately disposed magnetic field lens means, all interposed between first and second conventional condenser lens means, such that the respective sextupole means are imaged on each other.
Claim 2
Dependent Claim
71 words
In an electron optic system, having a source of electrons, the improvement in the system for correction of third-order aberrations such that the point resolving power is reduced to less than 1.0 Angstrom unit, comprising: aligned first and second spaced sextupole means and an intermediately disposed magnetic field lens means, all interposed between first and second conventional condenser lens means, such that the respective sextupole means are imaged on each other.
Claim 3
Dependent Claim
32 words
The system of claim 1, for additional correction of fifth-order aberrations, wherein decapole means are disposed adjacent the respective sextupole means, such that the respective decapole means are imaged on each other.
Claim 4
Dependent Claim
27 words
The system of claim 1 wherein the optic system comprises a scanning transmission electron microscope having an electron source with a voltage greater than about 150 kolovolts.
Claim 5
Dependent Claim
29 words
The system of claim 1 wherein the length of each of the respective sextupole means is within the range from about 0.05 to about 0.1 of the distance therebetween.
Claim 6
Dependent Claim
29 words
The system of claim 4 wherein the length of each of the respective sextupole means is within the range from about 0.07 to about 0.1 of the distance therebetween.
Claim 7
Dependent Claim
23 words
The system of claim 1, having an objective lens whose focal length is within the range from about 3 to about 10 mm.
References Cited (Backward Citations)
US3952198A
Cited
US4303864A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-11-07 | 1987-05-09 | 1987-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-07 | 1991-05-09 | 1991-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-07 | 1995-05-09 | 1995-11-08 | $7700.00 | Window Closed / Lapsed |