Patent US3748467A successfully refreshed from Google Patents.
US3748467A
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US
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Scanning electron microscope
Assignee: Jeol Ltd
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Filing: 1971-09-07
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Granted: 1973-07-24
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Expires: 1991-09-07
Abstract
Abstract Disclosed is a scanning electron microscope which comprises the means for periodically changing the focal distance of the final condenser lens at two stages and the means for simultaneously displaying two scanning images corresponding to the two focal distances.
Inventors
- 👤 T Suganuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:44
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/153; H01J37/147; H01J37/15; H01J37/26; H01J37/28
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
99 words
A scanning electron microscope comprising a means for generating an electron beam, an electron lens for focusing the said electron beam on a specimen, a deflector for scanning the electron beam over the specimen, a detector for detecting the signal emitted by irradiating the electron beam on the specimen, a stigmator for correcting astigmatism of the said electron lens, the improvement comprising means for adjusting said stigmator including means for changing the focal distance of the electron lens automatically and periodically between two selected distances, and means for displaying two scanning images corresponding to each of said focal distances.
Claim 2
Dependent Claim
99 words
A scanning electron microscope comprising a means for generating an electron beam, an electron lens for focusing the said electron beam on a specimen, a deflector for scanning the electron beam over the specimen, a detector for detecting the signal emitted by irradiating the electron beam on the specimen, a stigmator for correcting astigmatism of the said electron lens, the improvement comprising means for adjusting said stigmator including means for changing the focal distance of the electron lens automatically and periodically between two selected distances, and means for displaying two scanning images corresponding to each of said focal distances.
Claim 3
Dependent Claim
28 words
A scanning electron microscope according to claim 1 wherein two cathode ray tubes comprise the means for displaying scanning images corresponding to each focal distance separately and individually.
Claim 4
Dependent Claim
36 words
A scanning electron microscope according to claim 2, comprising means for alternately providing a cut-off potential to the control grids of either one of the cathode ray tubes, the means being synchronized with the lens focus.
Claim 5
Dependent Claim
51 words
A scanning electron microscope according to claim 2, wherein the lens focus changing means includes a switching signal generator, a power source for alternately generating negative or positive D. C. currents according to the output signal of the said generator, and an auxiliary lens coil excited by the said power source.
Claim 6
Dependent Claim
43 words
A scanning electron microscope according to claim 2, wherein the lens focus changing means includes a switching signal generator and a means for changing the exciting current of the electron lens between two selected distances according to output signal of the said generator.
Claim 7
Dependent Claim
22 words
A scanning electron microscope according to claim 4, wherein the switching signal generator synchronizes with the deflector for the scanning electron beam.
Claim 8
Dependent Claim
29 words
A scanning electron microscope according to claim 1, wherein one cathode ray tube displays different scanning images on different areas of its screen corresponding to the two focal distances.
Claim 9
Dependent Claim
52 words
A scanning electron microscope according to claim 7, comprising means for supplying a deflecting current to the deflecting coil of the cathode ray tube, the deflecting current consisting of a horizontal scanning signal current and of a D. C. bias positive or negative signal current synchronized with the said horizontal scanning signal.
Claim 10
Dependent Claim
43 words
A scanning electron microscope according to claim 7, wherein the lens focus changing means comprises a switching signal generator and means responsive to the output signal of the said generator for changing the exciting current of the electron lens between two selected distances.
Claim 11
Dependent Claim
50 words
A scanning electron microscope according to claim 7, wherein the lens focus changing means comprises a switching signal generator, a power source for alternately generating negative or positive D. C. current according to the output signal of the said generator, and an auxiliary lens coil excited by the power source.
Claim 12
Dependent Claim
23 words
A scanning electron microscope according to claim 9, wherein the switching signal generator is synchronized with the deflector for the scanning electron beam.
Claim 13
Dependent Claim
34 words
A scanning electron microscope according to claim 1, wherein the means for displaying the scanning images provides two scanning images alternately displayed at time intervals on the screen of a single cathode ray tube.
Claim 14
Dependent Claim
43 words
A scanning electron microscope according to claim 12, wherein the lens focus changing means comprises a switching signal generator and a means responsive to the output signal of the generator for changing the exciting current of the electron lens between two selected distances.
Claim 15
Dependent Claim
50 words
A scanning electron microscope according to claim 12, wherein the lens focus changing means comprises a switching signal generator, a power source for alternately generating negative or positive D. C. current according to the output signal of the said generator, and an auxiliary lens coil excited by said power source.
Claim 16
Dependent Claim
23 words
A scaning electron microscope according to claim 13, wherein the switching signal generator is synchronized with the deflector for scanning the electron probe.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |