US2259994A - Electron microscope - Google Patents
Electron microscope Download PDFInfo
- Publication number
- US2259994A US2259994A US367138A US36713840A US2259994A US 2259994 A US2259994 A US 2259994A US 367138 A US367138 A US 367138A US 36713840 A US36713840 A US 36713840A US 2259994 A US2259994 A US 2259994A
- Authority
- US
- United States
- Prior art keywords
- magnetic
- elements
- electron
- members
- tubular
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000004907 flux Effects 0.000 description 6
- 230000004048 modification Effects 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000010894 electron beam technology Methods 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000008358 core component Substances 0.000 description 2
- 239000000696 magnetic material Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000306 component Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000003302 ferromagnetic material Substances 0.000 description 1
- -1 for example Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
- H01J37/10—Lenses
- H01J37/14—Lenses magnetic
- H01J37/141—Electromagnetic lenses
Definitions
- the present invention relates to improvements in focused beam discharge devices'and is' primarily applicable in connection with so called electron microscopes.
- v j
- the electron microscope is a device in which magnification effects, analogousto those realized with an optical microscope, are obtained by appropriate refraction of an electron beam which is caused to be reflected from, or projected through, the object to be magnified.
- the desired electron refraction may be obtained bypassing the elec tron beam through an electrostatic or magnetic field of such character as to produce strong focusing of the beam.
- FIG. 1 represents a discharge tube embodying the invention
- Fig. 2 is afragmentary view indicating a possible modification of the invention
- Fig. 3 is a transverse cross-section of a second modification
- Figs. 4 and 5 conjointly illustrate still a third modification.
- a discharge device of the cathode ray type which is provided at one end with-means for producing the impingement of electrons thereof, and thus to provide a visible image Whose nature is determinedby the characterof the impinging electron stream.
- these elements are constituted of a ferro-magneticmaterial, for example, iron or ironchrome alloy, and are positioned in end-to-end relationship so as to be traversed successively by the electron beam.
- tubular elements l1 and I8 are respectively providedwith inwardly tapered portions 19 and 20 which converge toward central aperturesZl' and 22. It is the function of the elements and of the tapered portions thereof to provide pole'piecesfor the establishment of an axial magnetic field in the gap which separates the two elements. Due to the axial symmetry of the elements, the field thus provided is itself axiallysymmetrical and is, therefore, well adapted to the-purposesof focusing an electron stream in such fashion as to produce magnification effects.
- a metal ring 25 which is of non-magnetic character and of such form as snugly to engage the surfaces of the elements.
- the metal ring 25' is shown as being provided with a removable member, showndiagrammettically at 26, which serves for the introduction into the tube of a mounting fixture for an object which is to be investigated by the use of the electron microscope. The presence of such a mounting is illustrated diagrammatically at 21.
- a coil 30 having a suificient number of turns to permit the establishment of a strong magnetic field upon energization thereof.
- a low reluctance path for the flux established by the coil 30 is provided by means of a U-shaped core structure 3
- the function of this core which should be of magnetic material, is to permit a strong magnetic field to :be established in the gap between the magneticelements l1 and !8 in spite of the fact thatthe exciting coil itself is appreciably displaced from the gap.
- FIG. 2 represents the central portion of a cathode ray tube-ethat is, a tube with the electrode structure and theviewing win: dow and its associated bulb removed. It is the purpose of this figure to show an arrangement by which a series of magnetic lenses having the characteristics of my invention may be arranged in cascade. This may be accomplished in one way by the use of a generally cylindrical magnetic. member in combination with two additional elements 35 and 31 of similar cross-section, which are positioned adjacent the respective extremities of the element 35.
- the magnetic lenses which are formed by these elements, and especially by the inwardly tapered end portions thereof, are energized by a pair of magnetic coils 39 and 45.
- a further aspect of the invention which is also illustrated in Fig. 2 comprises the utilization of articulated joints in the magnetic structure, as indicated at and 4.3.
- FIG. 3 represents a transverse cross-section taken through a discharge device of the general character of that shown in Fig. 1.
- the element represents in section a tubular magnetic part such as the part I! of- Fig. 1.
- a number of magnetic core components indicated respectively at 5
- additional core components to 58 inclusive which extend perpendicularly thereto.
- Each of the core structures is assumed to be closed by the provision of additional leg portions which respectively connect with a second cylindrical element positioned in end-to-end relationship with the element 50.
- each of the core portions 55 to 58 is provided with a coil winding as shown at 60, BI, 62 and 63.
- the resultant construction therefore, represents a multiplication of the arrangement of Fig. 1 in which four U-shaped'core structures, each excited by its own exciting coil, are provided at ninety degree positions around the axis of the discharge device and in which all such structures contribute to the energizae tion of a single magnetic lens of which the element 5B constitutes one component.
- FIGs. 4 and 5 illustrate a still further variation of the invention.
- tubular pole pieces f extending cylinder 69 of magnetic material are illustrated.
- a discharge device including means for producing a beam of moving charges, a vacuum-tight discharge enclosure providing an elongated chamber to be traversed bythe beam, said enclosure being-iormed in part of a pair of tubular magnetic members positionedv n mu u y c en -end e ation t p vide a lens space between them, magnetic fieldproducing means associated with the members for establishinga magnetic, flux through the said lens space to produce a desired focusing efiect on the said beam, and means externally closing the gap between the members to maintain the vacuum-tight quality of the enclosure.
- a, discharge device includ: ing means for producing a beam of moving charges, a vacuum-tight discharge enclosure providing a relatively elongated chamber to be traversed by the beam, said enclosure being formed in part of a pair of tubular magnetic members positioned in mutually spaced end-to-end relation to provide a lens space between them, a magnetic structure externally connected between the members for establishing'a mag'netic flux through the said space to produce a desired focusing effect on the said beam, and non-magnetic means peripherally sealing the gap between the members to maintain the vacuum -tight quality of the enclosure.
- a discharge device including means for producing a beam of moving charges, a vacuum-tight discharge enclosure formed in part of a pair of tubular magnetic members arranged to be successively traversed by the beam, said members having conically tapered extremities which are positioned in juxtaposed relation to provide a lens space between them, magnetic field-producing means associated with the'said members for establishing a magnetic flux through the lens space adapted to produce a desired focusing efiect on the said beam, and a ring of nonmagnetic material interposed between the'opposed conically tapered faces of said members for hermetically sealing the gap between them.
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2259994X | 1939-03-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2259994A true US2259994A (en) | 1941-10-21 |
Family
ID=7992787
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US367138A Expired - Lifetime US2259994A (en) | 1939-03-17 | 1940-11-25 | Electron microscope |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US2259994A (fr) |
| NL (1) | NL59196C (fr) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2619607A (en) * | 1951-03-10 | 1952-11-25 | Glaser Steers Corp | Internal focusing device |
| US2847607A (en) * | 1953-04-29 | 1958-08-12 | Bell Telephone Labor Inc | Magnetic focusing system |
-
0
- NL NL59196D patent/NL59196C/xx active
-
1940
- 1940-11-25 US US367138A patent/US2259994A/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2619607A (en) * | 1951-03-10 | 1952-11-25 | Glaser Steers Corp | Internal focusing device |
| US2847607A (en) * | 1953-04-29 | 1958-08-12 | Bell Telephone Labor Inc | Magnetic focusing system |
Also Published As
| Publication number | Publication date |
|---|---|
| NL59196C (fr) |
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