US3889114A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron microscope for dark-field illumination
Assignee: US Philips Corp
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Filing: 1974-03-11
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Granted: 1975-06-10
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Expires: 1994-03-11
Abstract
Abstract In an electron microscope dark-field illumination is obtained by including an annular diaphragm between the electron source and the second condenser lens and by varying the energisation of the condenser lenses whilst retaining imaging of the electron source on the specimen. The specimen is illuminated by a beam in the form of a hollow cone of varying apical angle. By means of a known objective diaphragm those electrons are selected from the scattered beam for the purpose of image formation which leave the specimen within a narrow cone about the optical axis, irrespective of the angle of incidence.
Inventors
- 👤 Van Oostrum Karel Jan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 04:04
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/26; H01J37/261; H01J37/265
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
102 words
Electron microscope having an annular diaphragm which is arranged about an optical axis and serves to illuminate a specimen at an angle to the optical axis, characterized in that the electron microscope includes, viewed in the direction of propagation of the electron beam, after an electron source a first condenser lens and a second condenser lens for imaging the electron source on the specimen, in that the condenser system is provided with a supply source which is individually adjustable for each of the condenser lenses, and in that the annular diaphragm is disposed between the electron source and the second condenser lens.
Claim 2
Dependent Claim
102 words
Electron microscope having an annular diaphragm which is arranged about an optical axis and serves to illuminate a specimen at an angle to the optical axis, characterized in that the electron microscope includes, viewed in the direction of propagation of the electron beam, after an electron source a first condenser lens and a second condenser lens for imaging the electron source on the specimen, in that the condenser system is provided with a supply source which is individually adjustable for each of the condenser lenses, and in that the annular diaphragm is disposed between the electron source and the second condenser lens.
Claim 3
Dependent Claim
41 words
Electron microscope as claimed in claim 1, characterized in that in the condenser supply source the energisation for the two condenser lenses is coupled for automatic adjustment for source imaging on the specimen with varying energisation of the first condenser lens.
Claim 4
Dependent Claim
23 words
Electron microscope as claimed in claim 1 characterized in that the annular diaphragm is included in the construction of the first condenser lens.
Claim 5
Dependent Claim
23 words
Electron microscope as claimed in claim 1, characterized in that the supply source for the condenser system is provided with a programmable timer.
Claim 6
Dependent Claim
29 words
Electron microscope as claimed in claim 4, characterized in that it includes a television camera tube coupled to the timer and an image recording device connectd to said tube.
Claim 7
Dependent Claim
22 words
Electron microscope as claimed in claim 5, characterized in that a chromatiser and a colour monitor are associated with the recording device.
References Cited (Backward Citations)
US2464419A
Cited
US3795813A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |