US3010046A - Cathode structure - Google Patents
Cathode structure Download PDFInfo
- Publication number
- US3010046A US3010046A US273386A US27338652A US3010046A US 3010046 A US3010046 A US 3010046A US 273386 A US273386 A US 273386A US 27338652 A US27338652 A US 27338652A US 3010046 A US3010046 A US 3010046A
- Authority
- US
- United States
- Prior art keywords
- cathode
- barium
- wall
- tube
- cup
- 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
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/13—Solid thermionic cathodes
- H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
- H01J1/28—Dispenser-type cathodes, e.g. L-cathode
Definitions
- cathode structures have been built comprising a closed structure having a porous tungsten wall in one end of the structure. Inside the structure there is a barium-strontium carbonate reservoir. This cathode is satisfactory for some purposes. However, for many purposes the high temperature required during activation and the migration of barium to nearby structures, has been found to cause it to be undesirable.
- the emission mechanism of this structure has been ascribed to the diffusion of barium through the tungsten wall when the barium carbonate was converted to barium oxide and reduced by the tungsten.
- Another object of our invention is to provide a cathode which does not contain materials which require chemical reduction or outgassing.
- Another object of our invention is to provide a cathode having means for producing a high degree of control of the temperatures involved.
- Still another object of our invention is to provide a cathode having a reservoir containing barium which may be readily reactivated after exposure to air.
- An ancillary object of our invention is to provide a new and useful electronic apparatus.
- FIGURE 1 is a cross sectional showing of a cathode embodying our invention
- FIG. 2 is a schematic showing of a cathode in accordance with our invention inside a cathode-ray tube.
- an outer cylindrical wall 4 of electrically conducting material such as molybdenum Inside the outer cylindrical wall there is a cylindrical cup-shaped box 6, the outside dimensions of which near the open end 8 of the cup 6 are substantially equal to the inside dimensions of the outer cylindrical wall 4. At the end of the cup opposite the open end, the cup walls extend inward so as to form a smaller cylindrical cavity 10 which has one open end 12, opening into the main part of the cup-shaped box 6.
- tungsten plug 14 which completely fills the open end 8 of the cup 6.
- a barium slug 18 with a coating 20 of a protecting metal preferably nickel thereon.
- Welds 22 are provided between the barium slug 18 and the wall of the small cavity 10, for maintaining the slug 13 in a fixed position.
- Primary heating coils 23 encircle the small cavity 10 at the bottom of the cup 6 for heating the nickel coated barium 18-, 20 so as to cause evaporation of the barium.
- a secondary heating coil 24 for controlling the temperature of the tungsten plug 14.
- the tungsten plug 14, the wall of the inner cup 6 and the outer cylindrical wall 4 are preferably welded together.
- the present apparatus has the advantage that no materials are present which require chemical reduction or outgassing as was required previously in cathodes of this type.
- two separate heating coils one in the region of the tungsten plug and the other in the region of the barium, it is possible to control the temperature of the emitting surface and the temperature of the barium reservoir independently of each other when desired. Such a control allows a material lengthening of the life of the cathode.
- FIGURE 2 we have shown a cathode-ray tube cornprising an evacuated envelope 26 having therein an anode 2.8 and a cathode 30 of the type shown in FIG. 1 and described above.
- this cathode in a cathode-ray tube, it is nevertheless understood that it may be used in many other types of tubes.
- the resistance of this cathode to back bombardment is excellent, therefore, it should be exceptionally useful in magnetrons and other electron tubes.
- a cathode comprising a molybdenum tube having therein a nickel coated barium slug which is surrounded by a heater coil, a wall of molybdenum across said tube on one side of said barium, and a wall of porous tungsten across said tube on the other side of said barium.
- a cathode structure comprising, a supporting tube across said tube on the other side of said barium, and a heater coil in the region of said tungsten wall for heating said wall.
- a cathode structure comprising, a supporting tube of heat resistant material having an open end, a piece of 4 r 6.
- a cathode comprising a nickel coated barium slug enclosed in a chamber, said chamber having part of its I walls composed of a porous metal, and a heating element near said chamber for heating said siug. 5 References Cited in the file of this patent UNITED STATES PATENTS 'Espe June 21, 193s Lemmens et a1. Feb. 27, 1951
Landscapes
- Solid Thermionic Cathode (AREA)
Description
Nov. 21, 1961 H. J. DAILEY ETAL 3,010,046
CATHODE STRUCTURE Filed Feb. 26, 1952 Fig. I
28 2e Flg. 3Q
wmwzsszs; INVENTORS Hampton J. Bailey and R'odger G. Larson.
rib;
United States 3,010,046 CATHODE STRUCTURE Hampton J. Dailey, Verona, and Rodger G. Larson, East Orange, N.J., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 26, 1952, Scr. No. 273,386 6 Claims. (Cl. 313-346) Our invention relates to electron discharge tubes, and more particularly to a cathode for such tubes.
In accordance with the prior art, of which we are aware, cathode structures have been built comprising a closed structure having a porous tungsten wall in one end of the structure. Inside the structure there is a barium-strontium carbonate reservoir. This cathode is satisfactory for some purposes. However, for many purposes the high temperature required during activation and the migration of barium to nearby structures, has been found to cause it to be undesirable.
The emission mechanism of this structure has been ascribed to the diffusion of barium through the tungsten wall when the barium carbonate was converted to barium oxide and reduced by the tungsten.
It is accordingly an object of our invention to provide an improved cathode for use in another electron discharge device.
Another object of our invention is to provide a cathode which does not contain materials which require chemical reduction or outgassing.
Another object of our invention is to provide a cathode having means for producing a high degree of control of the temperatures involved.
Still another object of our invention is to provide a cathode having a reservoir containing barium which may be readily reactivated after exposure to air.
An ancillary object of our invention is to provide a new and useful electronic apparatus.
The novel features which we consider characteristic of our invention are set forth with more particularity in the appended claims. The invention, however, with respect to both the organization and the operation thereof, together with other objects and advantages may be best understood from the following description of specific embodiments when read in connection with the accompanying drawing, in which:
FIGURE 1 is a cross sectional showing of a cathode embodying our invention,
FIG. 2 is a schematic showing of a cathode in accordance with our invention inside a cathode-ray tube.
In accordance with our invention, we provide an outer cylindrical wall 4 of electrically conducting material such as molybdenum. Inside the outer cylindrical wall there is a cylindrical cup-shaped box 6, the outside dimensions of which near the open end 8 of the cup 6 are substantially equal to the inside dimensions of the outer cylindrical wall 4. At the end of the cup opposite the open end, the cup walls extend inward so as to form a smaller cylindrical cavity 10 which has one open end 12, opening into the main part of the cup-shaped box 6.
Across the open end 8 of the cup-shaped box 6 there is a sintered porous tungsten plug 14 which completely fills the open end 8 of the cup 6. On the outer side of the tungsten plug 14 that plug has a concave surface 16 for providing focusing of electrons emitted from the Patented Nov. 21, 1961 tungsten wall. In the small cavity 10 at the bottom of the cup 6, there is a barium slug 18 with a coating 20 of a protecting metal preferably nickel thereon. Welds 22 are provided between the barium slug 18 and the wall of the small cavity 10, for maintaining the slug 13 in a fixed position.
The present apparatus has the advantage that no materials are present which require chemical reduction or outgassing as was required previously in cathodes of this type. By employing two separate heating coils, one in the region of the tungsten plug and the other in the region of the barium, it is possible to control the temperature of the emitting surface and the temperature of the barium reservoir independently of each other when desired. Such a control allows a material lengthening of the life of the cathode.
By controlling the rate of evaporation of the barium which may be achieved by controlling the rate of evolution from the slug and by using the getter action of the barium, it is relatively easy to reactivate the cathode after exposure to air.
In FIGURE 2 we have shown a cathode-ray tube cornprising an evacuated envelope 26 having therein an anode 2.8 and a cathode 30 of the type shown in FIG. 1 and described above.
While we have shown this cathode in a cathode-ray tube, it is nevertheless understood that it may be used in many other types of tubes. For example, the resistance of this cathode to back bombardment is excellent, therefore, it should be exceptionally useful in magnetrons and other electron tubes.
Although we have shown and described specific embodiments of our invention, we are aware that other modifications thereof are possible. Our invention, therefore is not to be restricted except insofar as is necessitated by the prior art and the spirit of the invention.
We claim as our invention:
1. A cathode comprising a molybdenum tube having therein a nickel coated barium slug which is surrounded by a heater coil, a wall of molybdenum across said tube on one side of said barium, and a wall of porous tungsten across said tube on the other side of said barium.
2. A cathode structure comprising, a supporting tube across said tube on the other side of said barium, and a heater coil in the region of said tungsten wall for heating said wall.
4. A cathode structure comprising, a supporting tube of heat resistant material having an open end, a piece of 4 r 6. A cathode comprising a nickel coated barium slug enclosed in a chamber, said chamber having part of its I walls composed of a porous metal, and a heating element near said chamber for heating said siug. 5 References Cited in the file of this patent UNITED STATES PATENTS 'Espe June 21, 193s Lemmens et a1. Feb. 27, 1951
Claims (1)
1. A CATHODE COMPRISING A MOLYBDENUM TUBE HAVING THEREIN A NICKEL COATED BARIUM SLUG WHICH IS SURROUNDED BY A HEATER COIL, A WALL OF MOLYBDENUM ACROSS SAID TUBE ON ONE SIDE OF SAID BARIUM, AND A WALL OF POROUS TUNGSTEN ACROSS SAID TUBE ON THE OTHER SIDE OF SAID BARIUM.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US273386A US3010046A (en) | 1952-02-26 | 1952-02-26 | Cathode structure |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US273386A US3010046A (en) | 1952-02-26 | 1952-02-26 | Cathode structure |
Publications (1)
Publication Number | Publication Date |
---|---|
US3010046A true US3010046A (en) | 1961-11-21 |
Family
ID=23043705
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US273386A Expired - Lifetime US3010046A (en) | 1952-02-26 | 1952-02-26 | Cathode structure |
Country Status (1)
Country | Link |
---|---|
US (1) | US3010046A (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3284657A (en) * | 1963-06-03 | 1966-11-08 | Varian Associates | Grain-oriented thermionic emitter for electron discharge devices |
US3320463A (en) * | 1962-07-23 | 1967-05-16 | Gen Electric | Electron discharge tube having an improved electrode mounting structure |
US3441779A (en) * | 1966-04-06 | 1969-04-29 | Siemens Ag | Cathode having an end face carrier for an emission substance and the production thereof |
US3441780A (en) * | 1966-03-29 | 1969-04-29 | Siemens Ag | Indirectly heated dispenser cathode for electronic discharge devices |
US3454816A (en) * | 1966-08-05 | 1969-07-08 | Siemens Ag | Indirectly heated dispenser cathode for electric discharge tube |
US3474282A (en) * | 1965-06-30 | 1969-10-21 | Siemens Ag | Electron gun for electron tubes in cathode heater device |
US3911309A (en) * | 1972-09-18 | 1975-10-07 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Electrode comprising a porous sintered body |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2121589A (en) * | 1934-06-28 | 1938-06-21 | Westinghouse Electric & Mfg Co | Emissive incandescent cathode |
US2543728A (en) * | 1947-11-26 | 1951-02-27 | Hartford Nat Bank & Trust Co | Incandescible cathode |
-
1952
- 1952-02-26 US US273386A patent/US3010046A/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2121589A (en) * | 1934-06-28 | 1938-06-21 | Westinghouse Electric & Mfg Co | Emissive incandescent cathode |
US2543728A (en) * | 1947-11-26 | 1951-02-27 | Hartford Nat Bank & Trust Co | Incandescible cathode |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3320463A (en) * | 1962-07-23 | 1967-05-16 | Gen Electric | Electron discharge tube having an improved electrode mounting structure |
US3284657A (en) * | 1963-06-03 | 1966-11-08 | Varian Associates | Grain-oriented thermionic emitter for electron discharge devices |
US3474282A (en) * | 1965-06-30 | 1969-10-21 | Siemens Ag | Electron gun for electron tubes in cathode heater device |
US3441780A (en) * | 1966-03-29 | 1969-04-29 | Siemens Ag | Indirectly heated dispenser cathode for electronic discharge devices |
US3441779A (en) * | 1966-04-06 | 1969-04-29 | Siemens Ag | Cathode having an end face carrier for an emission substance and the production thereof |
US3454816A (en) * | 1966-08-05 | 1969-07-08 | Siemens Ag | Indirectly heated dispenser cathode for electric discharge tube |
US3911309A (en) * | 1972-09-18 | 1975-10-07 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Electrode comprising a porous sintered body |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2543728A (en) | Incandescible cathode | |
US2107945A (en) | Cathode structure | |
US2147447A (en) | Glow cathode | |
US2741717A (en) | Dispenser type cathode having gettercoated parts | |
US3010046A (en) | Cathode structure | |
US2201731A (en) | Discharge tube electrode assembly | |
US3902090A (en) | Short-arc gas discharge lamp | |
US2135941A (en) | Electrode structure | |
US2518879A (en) | Hydrogen thyratron | |
US2233917A (en) | Black coating for electron discharge devices | |
US2167852A (en) | Electron discharge device | |
US1874753A (en) | Controlled arc discharge apparatus | |
US2241345A (en) | Electron emissive cathode | |
US2959702A (en) | Lamp and mount | |
US2845567A (en) | Indirectly heated thermionic cathode | |
US2189636A (en) | Long life cathode for electron tubes | |
US3361922A (en) | Cathode-grid assembly with means for preventing the formation of electron emissive materials upon the grid element | |
US2961566A (en) | Fluorescent lamp | |
US2381632A (en) | Electron discharge device | |
US2283639A (en) | Electric discharge device | |
US1961814A (en) | Electrical discharge device | |
US2995674A (en) | Impregnated cathodes | |
US2027241A (en) | Thermionic discharge device | |
US2892115A (en) | Cathode structures | |
US2459997A (en) | Partially indirectly heated cathode structure for gas tubes |