Patent US4687931A successfully refreshed from Google Patents.
US4687931A
Expired / Lapsed
US
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Scanning electron microscope
Assignee: Hitachi Ltd
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Filing: 1986-04-29
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Granted: 1987-08-18
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Expires: 2006-04-29
Abstract
Abstract Herein disclosed is a scanning electron microscope in which an electron beam is finely focused into a small beam diameter and irradiated on a specimen so that the focused electron beam may scan two-dimensionally to obtain an image with signals of secondary electrons generated from the specimen. The scanning electron microscope is equipped with means for making the moving speed of a specimen stage, which is movable two-dimensionally in response to electric control signals, automatically variable in association with the magnification of the image.
Inventors
- 👤 Satoru Fukuhara
- 👤 Hideo Todokoro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:50
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/20; H01J37/26; H01J37/28
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
91 words
A scanning electron microscope comprising: electron beam focusing means for focusing and irradiating a focused electron beam on a specimen; deflecting means for two-dimensionally scanning said electron beam; detecting means for detecting a secondary electron signal generated from said specimen to form an image; moving means for two-dimensionally moving a specimen stage on which said specimen is carried; and control means making variable the two-dimensional moving speed of said specimen stage in association with the magnification of said image by controlling said moving means in accordance with an electric control signal.
Claim 2
Dependent Claim
91 words
A scanning electron microscope comprising: electron beam focusing means for focusing and irradiating a focused electron beam on a specimen; deflecting means for two-dimensionally scanning said electron beam; detecting means for detecting a secondary electron signal generated from said specimen to form an image; moving means for two-dimensionally moving a specimen stage on which said specimen is carried; and control means making variable the two-dimensional moving speed of said specimen stage in association with the magnification of said image by controlling said moving means in accordance with an electric control signal.
Claim 3
Dependent Claim
70 words
A scanning electron microscope according to claim 1, wherein said control means makes the moving speed V of said specimen stage so automatically variable in association with the magnification of said image as is expressed by V*=M.V= constant if: the moving speed of said specimen stage is denoted at V; the magnification of said image is denoted at M; and the moving speed of said image is denoted at V*.
Claim 4
Dependent Claim
62 words
A scanning electron microscope according to claim 1, wherein said control means includes: a basic pulse generation circuit for generating pulses; a frequency control circuit for varying the frequency of the pulses of said basic pulse generation circuit in association with a magnification; and a pulse motor adapted to be driven in the frequency of the output of said frequency control circuit.
References Cited (Backward Citations)
US4233510A
Cited
US4393309A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-17 | 1991-02-16 | 1991-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-17 | 1995-02-16 | 1995-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-17 | 1999-02-16 | 1999-08-18 | $7700.00 | Window Closed / Lapsed |