GB720776A - Improvements relating to magnetic focusing devices for electron beams - Google Patents
Improvements relating to magnetic focusing devices for electron beamsInfo
- Publication number
- GB720776A GB720776A GB5911/53A GB591153A GB720776A GB 720776 A GB720776 A GB 720776A GB 5911/53 A GB5911/53 A GB 5911/53A GB 591153 A GB591153 A GB 591153A GB 720776 A GB720776 A GB 720776A
- Authority
- GB
- United Kingdom
- Prior art keywords
- washers
- cylinder
- magnets
- pole pieces
- annular
- 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
Links
- 238000010894 electron beam technology Methods 0.000 title abstract 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract 8
- 229910052742 iron Inorganic materials 0.000 abstract 4
- 239000000696 magnetic material Substances 0.000 abstract 3
- 230000004048 modification Effects 0.000 abstract 2
- 238000012986 modification Methods 0.000 abstract 2
- 230000004907 flux Effects 0.000 abstract 1
- 230000035699 permeability Effects 0.000 abstract 1
- 230000000717 retained effect Effects 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
- H01J29/58—Arrangements for focusing or reflecting ray or beam
- H01J29/64—Magnetic lenses
- H01J29/68—Magnetic lenses using permanent magnets only
Landscapes
- Particle Accelerators (AREA)
- Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
Abstract
720,776. Electron beam apparatus. GENERAL ELECTRIC CO. March 3, 1953 [March 4, 1952], No. 5911/53. Class 39 (1) A focussing magnet assembly for a cathode-ray tube comprises a hollow cylinder 13 of magnetic material provided at its ends with radially extending annular pole pieces 14, 15, and a permanent magnet or plurality of permanent magnets 17, 18 extending between the pole pieces. The cylinder 13 is secured within the end of the cylindrical second anode 11 of the electron gun structure. The anode cylinder is of non-magnetic material. Iron washers 20, 21 provide extensions of the pole pieces outside the anode cylinder 11. Three magnets, equally spaced circumferentially, only two of which 17, 18 are shown, are retained in position by washers 24, 25 provided with suitable openings for receiving the ends of the magnets. The wall 16a of the cylinder 13 is graduated in thickness to establish a desired distribution of magnetomotive force along the magnet structure; the thickness of the wall is graduated by provided annular recesses 26 of varying depths. By making the depths of these recesses longer than their widths, the focussing field is shielded effectively from the fields of the magnets. The structure is designed to be free from spherical abberration or to introduce a desired spherical abberation compensating for spherical abberration introduced by the electron gun. The strength of the magnetic lens may be adjusted by means of an axially movable shunt outside the envelope of the tube. In a modification, Fig. 4 (not shown), the pole pieces 14, 15 and the washers 20, 21 seat together, the structure being supported on top of the anode cylinder 11. Non-magnetic washers are interposed between the pole pieces and the washers to ensure an even distribution of the magnetic flux across the interfaces. The washers have shaped flanges for retaining magnets. In another modification, Fig. 7 (not shown), the focussing field is shielded from the fields of the magnets by annular soft iron members provided inside and outside the anode cylinder 11. The inner wall of cylinder 13 is graduated in thickness, but not provided with recesses. In another arrangement, Fig. 6, the focussing assembly comprises an annular stack including soft iron pole pieces 44, 45 separated by a plurality of washers 46 of non-magnetic material with interposed washers 47 of high permeability iron, and by an annular magnet 48. The whole assembly is clamped together by an eyelet 49. The washers are graduated in thickness towards the centre of the assembly.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US274785A US2681421A (en) | 1952-03-04 | 1952-03-04 | Magnetic focusing structure for electron beams |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB720776A true GB720776A (en) | 1954-12-29 |
Family
ID=23049602
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB5911/53A Expired GB720776A (en) | 1952-03-04 | 1953-03-03 | Improvements relating to magnetic focusing devices for electron beams |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US2681421A (en) |
| GB (1) | GB720776A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1491388B1 (en) * | 1964-12-10 | 1970-01-15 | Philips Patentverwaltung | Klystron, preferably high-performance multi-chamber klystron, with at least one permanent magnet system with adjustable magnetic auxiliary connections |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL207373A (en) * | 1953-05-30 | |||
| US2925508A (en) * | 1955-07-28 | 1960-02-16 | Sperry Rand Corp | Electron beam focusing structure |
| US2915662A (en) * | 1956-08-24 | 1959-12-01 | Nat Video Corp | Centering arrangement and method for beams of cathode ray tubes |
| US3047758A (en) * | 1959-12-01 | 1962-07-31 | Machlett Laboraotries Inc | Cathode ray tubes |
| US3238715A (en) * | 1963-09-27 | 1966-03-08 | Paul D Reader | Electrostatic ion engine having a permanent magnetic circuit |
| US4162992A (en) * | 1978-01-03 | 1979-07-31 | Monsanto Company | Oxidation and ammoxidation catalysts |
| EP2827357A1 (en) | 2013-07-18 | 2015-01-21 | Fei Company | Magnetic lens for focusing a beam of charged particles |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2188579A (en) * | 1933-05-27 | 1940-01-30 | Loewe Radio Inc | Cathode ray tube, more particularly for television purposes |
| US2159534A (en) * | 1935-07-23 | 1939-05-23 | Firm Fernseh Ag | Cathode ray focusing coil |
| BE424327A (en) * | 1936-10-30 | |||
| DE973258C (en) * | 1938-03-08 | 1959-12-31 | Siemens Ag | Magnetic pole shoe lens with a small focal length for electron-optical enlargements in electron microscopes |
| GB515308A (en) * | 1938-05-25 | 1939-12-01 | Miller Harold | Improvements in or relating to magnetic electron lenses |
| US2418349A (en) * | 1945-12-13 | 1947-04-01 | Rca Corp | Method of and means for correcting for distortion in electron lens systems |
| US2503173A (en) * | 1946-10-18 | 1950-04-04 | Rca Corp | Permanent magnetic electron lens system |
-
1952
- 1952-03-04 US US274785A patent/US2681421A/en not_active Expired - Lifetime
-
1953
- 1953-03-03 GB GB5911/53A patent/GB720776A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1491388B1 (en) * | 1964-12-10 | 1970-01-15 | Philips Patentverwaltung | Klystron, preferably high-performance multi-chamber klystron, with at least one permanent magnet system with adjustable magnetic auxiliary connections |
Also Published As
| Publication number | Publication date |
|---|---|
| US2681421A (en) | 1954-06-15 |
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