US3746855A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron microscopes
Assignee: Associated Electrical Industries Ltd
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Filing: 1971-10-27
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Granted: 1973-07-17
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Expires: 1991-10-27
Abstract
Abstract In an electron microscope comprising an electromagnetic objective lens and at least three separate electromagnetic projector lenses, the rotations produced by the lenses are mutually balanced out, so that the final image has a substantially constant orientation with changes in magnification. Preferably, magnification is set by a single control knob. Preferably, the microscope has two modes of operation, for different magnification ranges, the rotations being balanced out in both ranges.
Inventors
- 👤 D Hilditch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:43
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/153
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
132 words
An electron microscope comprising: a. an electromagnetic objective lens for producing a first electron image of an object; b. at least three separate electromagnetic projector lenses disposed electron optically in series for producing a magnified electron image of said first electron image; and c. supply means for applying excitation currents to said lenses; d. said supply means having a control which when operated causes the magnification of the microscope to be varied by varying the amplitudes of the excitation currents applied to at least two of said lenses the variations in amplitude being in opposite senses; e. whereby changes in beam rotation in said lenses are in opposite senses and tend to balance out so that the magnified image but substantially constant orientation, at least over a range of values of magnification.
Claim 2
Dependent Claim
132 words
An electron microscope comprising: a. an electromagnetic objective lens for producing a first electron image of an object; b. at least three separate electromagnetic projector lenses disposed electron optically in series for producing a magnified electron image of said first electron image; and c. supply means for applying excitation currents to said lenses; d. said supply means having a control which when operated causes the magnification of the microscope to be varied by varying the amplitudes of the excitation currents applied to at least two of said lenses the variations in amplitude being in opposite senses; e. whereby changes in beam rotation in said lenses are in opposite senses and tend to balance out so that the magnified image but substantially constant orientation, at least over a range of values of magnification.
Claim 3
Dependent Claim
79 words
An electron microscope according to claim 1 wherein said control has a first range of operation over which it causes the magnification of the microscope to be varied by varying the amplitudes of the excitation currents applied to a first combination of said lenses, and a second range of operation over which it causes the magnification of the microscope to be varied by varying the amplitudes of the excitation currents applied to a second, different combination of said lenses.
Claim 4
Dependent Claim
24 words
An electron microscope according to claim 1 wherein said control is operative to vary the amplitudes of said excitation currents simultaneously with each other.
Claim 5
Independent Claim
114 words
A method of operating an electron microscope comprising an electromagnetic objective lens for producing a first electron image of an object, at least three separate electromagnetic projector lenses disposed electron optically in series for producing a magnified electron image of said first electron image, and supply means for applying excitation currents to said lenses, the method comprising the step of adjusting said supply means to vary the amplitudes of the excitation currents applied to at least two of said lenses the variations in amplitude being in opposite senses, whereby changes in beam rotation in said lenses are in opposite senses and tend to balance out so that the magnified image has substantially constant orientation.
Claim 6
Independent Claim
114 words
A method of operating an electron microscope comprising an electromagnetic objective lens for producing a first electron image of an object, at least three separate electromagnetic projector lenses disposed electron optically in series for producing a magnified electron image of said first electron image, and supply means for applying excitation currents to said lenses, the method comprising the step of adjusting said supply means to vary the amplitudes of the excitation currents applied to at least two of said lenses the variations in amplitude being in opposite senses, whereby changes in beam rotation in said lenses are in opposite senses and tend to balance out so that the magnified image has substantially constant orientation.
Claim 7
Dependent Claim
32 words
A method of operating an electron microscope according to claim 4, further comprising the step of adjusting said supply means to set the net rotation of said magnified image substantially to zero.
Claim 8
Dependent Claim
125 words
A method of operating an electron microscope according to claim 4, comprising the steps of: a. adjusting said supply means to vary the amplitudes of the excitation currents applied to a first combination of said lenses, the variations in amplitudes being in opposite senses, whereby changes in beam rotation in said lenses are in opposite senses and tend to balance out so that the magnifiied image has a substantially constant orientation; and b. adjusting said supply means to vary the amplitudes of the excitation currents applied to a second, different combination of said lenses in respective opposite senses whereby changes in beam rotation in said lenses are in opposite senses and tend to balance out so that the magnified image has a substantially constant orientation.
Claim 9
Dependent Claim
102 words
A method of operating an electron microscope according to claim 4 crmprising the steps of: a. adjusting said supply means to vary the amplitudes of the excitation currents applied to two or more of said projector lenses to vary the magnification of the microscope; and b. adjusting said supply means to vary the amplitudes of the excitation current applied to the objective lens to keep the object in focus; c. whereby changes in beam rotation in said projector lenses and said objective lens are in opposite senses and tend to balance out so that the magnified image has a substantially constant orientation.
References Cited (Backward Citations)
US3597608A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |