US2347990A - Electric discharge tube - Google Patents
Electric discharge tube Download PDFInfo
- Publication number
- US2347990A US2347990A US430602A US43060242A US2347990A US 2347990 A US2347990 A US 2347990A US 430602 A US430602 A US 430602A US 43060242 A US43060242 A US 43060242A US 2347990 A US2347990 A US 2347990A
- Authority
- US
- United States
- Prior art keywords
- cathode
- magnetic
- lines
- electrons
- concave
- 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
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
- H01J25/02—Tubes with electron stream modulated in velocity or density in a modulator zone and thereafter giving up energy in an inducing zone, the zones being associated with one or more resonators
- H01J25/32—Tubes with plural reflection, e.g. Coeterier tube
-
- 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
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J3/00—Details of electron-optical or ion-optical arrangements or of ion traps common to two or more basic types of discharge tubes or lamps
- H01J3/02—Electron guns
- H01J3/029—Schematic arrangements for beam forming
Definitions
- high-vacuum electron discharge tubes are required in which narrow, sharply limited electron beams are generated.
- Such tubes are useful in apparatus for oscillography and for television, and in modern transmitting tubes for generating ultra-short waves use is made of narrow electron beams. More particularly in the latter case it is essential that a sharply limited beam having the maximum possible current density should be generated, from which strongly concentrated space-charges can be formed by means of velocity modulation in order to bring about strong current impulses in an oscillatory circuit.
- cathode-ray tubes for television and oscillography attempts have been made to concentrate the electrons emitted by the cathode immediately after they pass out of the emissive surface so that no electrons get lost. It hasbeen suggested that the cathode be surrounded by a coil which is traversed by a current, so that the dispersion of the electrons will be prevented by the magnetic field thus excited. Rather poor results have been obtained in this way, since the magnetic field of such a coil is generally too homogeneous to bring about an eifective concentration of the cathode rays.
- the principal object of the invention is to obtain a strong concentration of the electrons in the form of an electron beam with great current density.
- the cathode is surrounded by a ferro magnetic body which is magnetically polarised in the direction of the electron beam.
- the magnetic field is a non-homogeneous fringe field which forces the electrons to move to the axis of the system.
- the magnetically polarised body may be a permanent hollow magnet, or it may be a ferro magnetic body which is magnetised by a magnet coil or similar means.
- the electrostatic lines of force which also determine the paths of the electrons, are caused to coincide as much as possible with the lines of force of the concentrating magnetic field.
- the emissive surface of the cathode should be arranged near the mouth of the polarised body, 1. e. in the region wherein the axial component of the magnetic field reverses its direction, while it is further desirable to use a concave emissive surface so that the electrostatic field converges sharply.
- An advantageous shape of the electrostatic lines of force may be promoted by giving the magnetic body a potential which is negative relatively to the. cathode so that this body also serves as a Wehnelt cylinder.
- the system is constitutedby. a cathode l, preferably an indirectly heated thermionic cathode, a grid shaped control electrode 2 and a first anode ii.
- the cathode is surrounded by a cylinder or tubular body 4 of term magnetic material whose edge 5 exhibits the properties of a magnetic pole.
- the body l may be a permanent magnet or it may be surrounded by a coil, not shown, which may if desired be outside the wall 6 of the tube, so that it can be traversed by an electric current to magnetise the cylinder 4.
- a potential difierence is preferably set up between the cathode I and the body 4, which renders the latter negative relatively to the cathode and promotes the convergence of the electric lines of force which pass out of the emissive surface of the cathode and are even at their origin directed along the longitudinal axis of the system due to the concave shape of the said cathode surface.
- the magnetic lines of force within the body t run from the edge 5 backwards, i. e., in the figure from the right to the left.
- the magnetic field at the mouth of the body 4 in front of the cathode is a fringing field and very non-homogeneous in contradistinction to the homogeneous field of the conventional magnet coil which has in the past been suggested for a similar purpose.
- the described system is highly adapted to be 1 used in tubes with directional electron beams for generating ultra-short Waves. It may also serve excellently in cathode-ray tubes for the reception of electrically transmitted pictures and more particularly in such tubes which serve for the. a
- An electronldischarge tube comprising a --'target adapted to receive electrons, a cathode having a concave surface with respect to said target'to emit electrons, means adjacent said target to develop-an electrostatic field having 1 lines of force extending in a direction substantially normal to elemental areas of said concave cathode surface, and a tubular ferro-magnetic bodysurrounding said cathode with its end near said cathode surface to develop a magnetic field having over said cathode surface lines of force substantially coincident with the lines of force of 'saidelectrostatic field.
- An electron discharge device comprising a target; an oppositely disposed cathode having an emitting surface concave to said target, a tubular ferro-magnetic body surrounding said cathode positioned with its end adjacent the rim of said surface to develop a magnetic field the fringe lines of which are substantially normal .to elemental areas of saidcathode surface and means adjacent said cathode to develop an electrostatic field having lines of force coincident .cathode, magnetic means surrounding and coextensive with the fringe lines directly adjacent said cathode.
- An electron discharge tube comprising a target, a concave cathode facing said target and aligned along the axis of said cathode therewith, a ferro-magnetic body having a tubular pole piece surrounding and adjacent the rim of said cathode to develop a magnetic field having a fringing field directed toward said axis immediately adjacent the concave surface of said cathode, and an apertured electrode in said fringing field and adjacent said cathode having a concave surface substantially conforming to that of said cathode to develop an electrostatic field having lines of force substantially coincident with thelines of force of said magnetic fringing 4.
- An electron discharge device comprising an indirectly heated cathode having a concave emitting surface positioned to direct an electron beam along'an axis extending through said said cathode and having one of its poles substantially flush with the rim of the concave emitting surface of said cathode todevelop a magnetic fringe field extending fora short distance in the direction ofsaid axis and intercepting said cathode surface and a mesh electrode substantially equidistant from the concave surface of said cathodeto direct electrons along paths intercepting said axis along the fringe field developed by said magnetic means.
- a cathode ray'tube comprising an evacuated envelope, a concave cathode, a target optially flush with the rim edge of the concave portion of said cathode.
Landscapes
- Cold Cathode And The Manufacture (AREA)
- Electrodes For Cathode-Ray Tubes (AREA)
- Discharge Lamp (AREA)
- Microwave Tubes (AREA)
- Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL219503X | 1940-07-03 |
Publications (1)
Publication Number | Publication Date |
---|---|
US2347990A true US2347990A (en) | 1944-05-02 |
Family
ID=19779267
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US430602A Expired - Lifetime US2347990A (en) | 1940-07-03 | 1942-02-12 | Electric discharge tube |
Country Status (8)
Country | Link |
---|---|
US (1) | US2347990A (xx) |
BE (1) | BE442068A (xx) |
CH (1) | CH219503A (xx) |
DE (1) | DE862039C (xx) |
FR (1) | FR874922A (xx) |
GB (2) | GB554828A (xx) |
NL (1) | NL60887C (xx) |
SE (1) | SE106343C1 (xx) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2619607A (en) * | 1951-03-10 | 1952-11-25 | Glaser Steers Corp | Internal focusing device |
US2727171A (en) * | 1951-01-11 | 1955-12-13 | Hartford Nat Bank & Trust Co | Ion trap for a cathode ray tube |
US2748307A (en) * | 1952-03-06 | 1956-05-29 | Gen Electric | Magnetically forcused electron discharge device |
US3217200A (en) * | 1962-01-23 | 1965-11-09 | Gen Electric | Internal magnetic lens for electron beams |
US5109179A (en) * | 1989-01-17 | 1992-04-28 | Thomson Tubes Electroniques | Electron gun provided with a device producing a magnetic field in the neighborhood of a cathode |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL254372A (xx) * | 1930-07-02 | |||
DE961735C (de) * | 1953-03-19 | 1957-04-11 | Fernseh Gmbh | Verfahren zur Zentrierung des Elektronenstrahls, insbesondere fuer Fernsehbildroehren, mit einem die Strahlachse ringfoermig umgebenden Permanentmagneten und Anordnung zur Durchfuehrung des Verfahrens |
DE1059565B (de) * | 1955-01-15 | 1959-06-18 | Sebel S A | Elektronische Lampe fuer Beleuchtungszwecke |
NL215805A (xx) * | 1956-02-24 | |||
NL278366A (xx) * | 1961-05-27 | |||
NL282676A (xx) * | 1961-08-31 | |||
DE2856244A1 (de) * | 1978-12-27 | 1980-07-03 | Kernforschungsanlage Juelich | Elektronenstosspektrometer |
-
0
- NL NL60887D patent/NL60887C/xx active
- BE BE442068D patent/BE442068A/xx unknown
-
1941
- 1941-07-01 DE DEN2330D patent/DE862039C/de not_active Expired
- 1941-07-02 CH CH219503D patent/CH219503A/de unknown
- 1941-07-03 SE SE413541A patent/SE106343C1/xx unknown
- 1941-08-28 FR FR874922D patent/FR874922A/fr not_active Expired
- 1941-11-17 GB GB14786/41A patent/GB554828A/en not_active Expired
-
1942
- 1942-02-12 US US430602A patent/US2347990A/en not_active Expired - Lifetime
-
1945
- 1945-11-06 GB GB29544/45A patent/GB603939A/en not_active Expired
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2727171A (en) * | 1951-01-11 | 1955-12-13 | Hartford Nat Bank & Trust Co | Ion trap for a cathode ray tube |
US2619607A (en) * | 1951-03-10 | 1952-11-25 | Glaser Steers Corp | Internal focusing device |
US2748307A (en) * | 1952-03-06 | 1956-05-29 | Gen Electric | Magnetically forcused electron discharge device |
US3217200A (en) * | 1962-01-23 | 1965-11-09 | Gen Electric | Internal magnetic lens for electron beams |
US5109179A (en) * | 1989-01-17 | 1992-04-28 | Thomson Tubes Electroniques | Electron gun provided with a device producing a magnetic field in the neighborhood of a cathode |
Also Published As
Publication number | Publication date |
---|---|
SE106343C1 (xx) | 1943-01-19 |
FR874922A (fr) | 1942-08-31 |
NL60887C (xx) | |
GB603939A (en) | 1948-06-25 |
CH219503A (de) | 1942-02-15 |
GB554828A (en) | 1943-07-21 |
DE862039C (de) | 1953-01-08 |
BE442068A (xx) |
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