US3283195A - Cold-cathode glow-discharge tube - Google Patents

Cold-cathode glow-discharge tube Download PDF

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Publication number
US3283195A
US3283195A US255831A US25583163A US3283195A US 3283195 A US3283195 A US 3283195A US 255831 A US255831 A US 255831A US 25583163 A US25583163 A US 25583163A US 3283195 A US3283195 A US 3283195A
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United States
Prior art keywords
cathode
discharge tube
caesium
gold
tube
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Expired - Lifetime
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US255831A
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Hall Raymond Frederick
Stocker Brian John
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/02—Details
    • H01J17/04—Electrodes; Screens
    • H01J17/06—Cathodes
    • H01J17/066—Cold cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0064—Tubes with cold main electrodes (including cold cathodes)
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0064—Tubes with cold main electrodes (including cold cathodes)
    • H01J2893/0065—Electrode systems
    • H01J2893/0066—Construction, material, support, protection and temperature regulation of electrodes; Electrode cups
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/922—Static electricity metal bleed-off metallic stock
    • Y10S428/9335—Product by special process
    • Y10S428/938—Vapor deposition or gas diffusion
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12771—Transition metal-base component
    • Y10T428/12861—Group VIII or IB metal-base component
    • Y10T428/12889—Au-base component

Definitions

  • the invention relates to a glow discharge tube comprising a caesium-activated cathode. It furthermore relates to a method of producing a glow discharge tube of this kind.
  • the activating layer consists, in accordance with the invention, of gold, the caesium-gold alloy CsAu and caesium oxide.
  • a glow discharge tube comprising a caesium-activated cathode caesium is distilled, in accordance with the invention, on a gold surface in the tube and is alloyed to the gold, after which oxidation is performed.
  • the gold may be provided in the form of a gold plate or it may be applied electrolytically to a metal surface or the gold layer may first be formed in the tube by evaporation on a metal plate, for example of molybdenum or on a molybdenum layer applied by evaporation to the wall, on a nickel layer or on a conductive tin oxide layer.
  • the evaporation of the gold layer may be carried out in vacuo or in a rare gas under low pressure.
  • the gold and the caesium can be alloyed at a temperature of about 100 C. for such a long time that the photo emission of the alloyed layer reaches a maximum value.
  • the oxidation of the caesium-gold layer can be performed by causing a discharge to be produced in a rare gas towards the alloyed layer and by allowing gradually such a quantity of oxygen to enter that the maintaining voltage attains a minimum value, after which the tube is filled with pure rare gas.
  • the oxidation may also take place in vacuo until the thermal emission of the hot layer reaches a maximum at about 100 C.
  • the tubes according to the invention have maintaining voltages which lie considerably below 50 v. not only at the beginning but also after a long operation. This is contrary to the known tubes, also the initial maintaining voltage of which lies above 50 v.
  • FIGS. 1 and 2 are sectional views of a discharge tube according to the invention parallel to and at right angles to the tube axis respectively and FIG. 3 shows the tube in an arrangement suitable -for carrying out the method according to the invention.
  • a filament wire 7 is supported by wires 8.
  • the filament wire has a thickness of 0.1 mm. and is made of molybdenum with a thin layer of platinum.
  • a gold wire 9 of a length of 10 mms. and a diameter of 0.1 mm.
  • Inside the cathode cylinder 5 there is provided the annular anode 17, which is supported by the wire 10.
  • the glass bulb is provided with two glass connections 3 and 4 for connection with the caesium source and with the exhaust pump and gas-filling system respectively.
  • a side bulb 12 is sealed in a vacuum-tight manner via the upper tube to the bulb 11, said side bulb containing a caesium pellet 13; the exhaust tube 14 leads to the pump and the gas-filling system 16.
  • the bulb 11 is surrounded by a high-frequency coil 15.
  • the pellet 13 may consist of two parts of silicon and one part of caesium bichromate or, for example one part of silicon and one part of caesium chrom-ate.
  • the tube is degassified in a furnace at 350 C. and after cooling the filament wire 7 and the gold wire 9 are degassified by passing current at a temperature such that the gold Wire melts and forms a pellet. Then the cathode cylinder 5 is degassified by heating it approximately to red glowing heat by means of high-frequency currents. The caesium pellet is decomposed by means of high-frequency currents, so that the caesium is precipitated in the bulb 12. Then the cathode cylinder 5 is again degassified. After cooking of the cathode cylinder the gold is evaporated in vacuo or in neon of a few mms. pressure.
  • the neon, if any, is pumped away and the caesium is evaporated from the bulb 12 towards the cathode cylinder 5 by heating the bulbs 11 and 12 at a temperature of about C.
  • the caesium alloys with the gold and this process is continued until the photo-emission of the cathode layer attains approximately the maximum value.
  • the time required to this end is about one and a half hours.
  • the bulb 12 is then sealed and the bulb 11 is filled with neon of a pressure of 10 mms.
  • a current of 10 rna. is passed through the tube and pure oxygen is slowly allowed to enter until the maintaining voltage has reached a minimum value.
  • the tube is filled with pure neon of a pressure between 5 and 20 mms.
  • test tubes manufactured by said method had initially maintaining voltages lying between 31 and 33 v. at a current of 10 ma, which value increased by a few volts after about 1000 hours.
  • the ignition voltage could initially even attain the low value of 60 v.
  • the tubes were filled with helium of a pressure between 3 and 20 mms., the maintaining voltages were initially 22 to 25 v., the fluctuation being, however, greater than with the neon filling. It is remarkable in this case that, in helium, maintaining voltages are attainable which are lower than the ionisation voltage of helium of 24.6 v.
  • the cathode may have free caesium.
  • a glow discharge tube comprising an envelope filled UNITED STATES PATENTS wit an ionizable medium and anode and cathode electrodes disposed therein, said cathode comprising a base g g 2? et 3:33 having an activating layer thereon consisting of gold, at 5 2254073 8/1941 i Cesium-gold alloy, and Cesium Oxide.
  • James 3 2.

Description

Nov. 1, 1966 H LL ETAL COLD-CATHODE GLOW-DISCHARGE TUBE Filed Feb. 4, 1963 INVENZQRS 0 F. HALL Z. STOCKER BRIAN BY United States Patent 3,283,195 COLD-CATHODE GLOW-DISCHARGE TUBE Raymond Frederick Hall, Crawley, and Brian John Stacker, Thornton Heath, England, assignors to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware Filed Feb. 4, 1963, Ser. No. 255,831 Claims priority, application Great Britain, Feb. 14, 1962, 5,666/ 62 3 Claims. (Cl. 313185) The invention relates to a glow discharge tube comprising a caesium-activated cathode. It furthermore relates to a method of producing a glow discharge tube of this kind.
With the hitherto known glow discharge tubes of the kind comprising a caesium-activated cathode the activating material consisted of some caesium compound. Thus, it is true, a low value of the maintaining voltage could be attained, but the lifetime was short. The invention has for its object to provide an improvement in this respect.
In a glow discharge tube comprising a caesium-activated cathode, the activating layer consists, in accordance with the invention, of gold, the caesium-gold alloy CsAu and caesium oxide.
In a method of producing a glow discharge tube comprising a caesium-activated cathode caesium is distilled, in accordance with the invention, on a gold surface in the tube and is alloyed to the gold, after which oxidation is performed.
In accordance with the invention the gold may be provided in the form of a gold plate or it may be applied electrolytically to a metal surface or the gold layer may first be formed in the tube by evaporation on a metal plate, for example of molybdenum or on a molybdenum layer applied by evaporation to the wall, on a nickel layer or on a conductive tin oxide layer.
The evaporation of the gold layer may be carried out in vacuo or in a rare gas under low pressure.
In the method according to the invention the gold and the caesium can be alloyed at a temperature of about 100 C. for such a long time that the photo emission of the alloyed layer reaches a maximum value.
In accordance with the invention the oxidation of the caesium-gold layer can be performed by causing a discharge to be produced in a rare gas towards the alloyed layer and by allowing gradually such a quantity of oxygen to enter that the maintaining voltage attains a minimum value, after which the tube is filled with pure rare gas. In accordance with the invention the oxidation may also take place in vacuo until the thermal emission of the hot layer reaches a maximum at about 100 C. The tubes according to the invention have maintaining voltages which lie considerably below 50 v. not only at the beginning but also after a long operation. This is contrary to the known tubes, also the initial maintaining voltage of which lies above 50 v.
The invention will now be described more fully with reference to the drawing, in which FIGS. 1 and 2 are sectional views of a discharge tube according to the invention parallel to and at right angles to the tube axis respectively and FIG. 3 shows the tube in an arrangement suitable -for carrying out the method according to the invention.
Referring to the figures reference numeral 1 designates the glass wall of the discharge tube, having a bottom 2, through which a number of supply pins are taken in a vacuum-tight manner; 5 designates a molybdenum cylinder which constitutes the cathode and which is mounted on supporting wires 6. A filament wire 7 is supported by wires 8. The filament wire has a thickness of 0.1 mm. and is made of molybdenum with a thin layer of platinum. Around the peak of the V-shaped filament wire 7 there is wound a gold wire 9 of a length of 10 mms. and a diameter of 0.1 mm. Inside the cathode cylinder 5 there is provided the annular anode 17, which is supported by the wire 10. The glass bulb is provided with two glass connections 3 and 4 for connection with the caesium source and with the exhaust pump and gas-filling system respectively.
As is shown in FIG. 3 a side bulb 12 is sealed in a vacuum-tight manner via the upper tube to the bulb 11, said side bulb containing a caesium pellet 13; the exhaust tube 14 leads to the pump and the gas-filling system 16. The bulb 11 is surrounded by a high-frequency coil 15.
The pellet 13 may consist of two parts of silicon and one part of caesium bichromate or, for example one part of silicon and one part of caesium chrom-ate.
First the tube is degassified in a furnace at 350 C. and after cooling the filament wire 7 and the gold wire 9 are degassified by passing current at a temperature such that the gold Wire melts and forms a pellet. Then the cathode cylinder 5 is degassified by heating it approximately to red glowing heat by means of high-frequency currents. The caesium pellet is decomposed by means of high-frequency currents, so that the caesium is precipitated in the bulb 12. Then the cathode cylinder 5 is again degassified. After cooking of the cathode cylinder the gold is evaporated in vacuo or in neon of a few mms. pressure. Subsequently the neon, if any, is pumped away and the caesium is evaporated from the bulb 12 towards the cathode cylinder 5 by heating the bulbs 11 and 12 at a temperature of about C. The caesium alloys with the gold and this process is continued until the photo-emission of the cathode layer attains approximately the maximum value. The time required to this end is about one and a half hours. The bulb 12 is then sealed and the bulb 11 is filled with neon of a pressure of 10 mms. A current of 10 rna. is passed through the tube and pure oxygen is slowly allowed to enter until the maintaining voltage has reached a minimum value. Then the tube is filled with pure neon of a pressure between 5 and 20 mms.
It has been found that test tubes manufactured by said method had initially maintaining voltages lying between 31 and 33 v. at a current of 10 ma, which value increased by a few volts after about 1000 hours. Dependent upon the arrangement of the electrodes the ignition voltage could initially even attain the low value of 60 v. If the tubes were filled with helium of a pressure between 3 and 20 mms., the maintaining voltages were initially 22 to 25 v., the fluctuation being, however, greater than with the neon filling. It is remarkable in this case that, in helium, maintaining voltages are attainable which are lower than the ionisation voltage of helium of 24.6 v. Instead of oxidizing the cathode during a glow discharge, it may be oxidized in vacuo, in which case the attainment of the maximum of the thermal emission at 100 C. indicates the correct degree of oxidation.
From investigations it appeared that the cathode may have free caesium.
What is claimed is: References Cited by the Examiner 1t.l A glow discharge tube comprising an envelope filled UNITED STATES PATENTS wit an ionizable medium and anode and cathode electrodes disposed therein, said cathode comprising a base g g 2? et 3:33 having an activating layer thereon consisting of gold, at 5 2254073 8/1941 i Cesium-gold alloy, and Cesium Oxide. James 3 2. A glow discharge tube as claimed in claim 1, where- 2:773:730 12/1956 Lewin 316 8 in the ionizable medium consists of neon or helium.
3. A glow discharge tube as claimed in claim 2, wherein JAMES LAWRENCE, Primary E a i 10 a 1S i P P Q F and a v. LAFRANCHI, Assistant Examiner. lower voltage 15 required to m-amtaln ionization.

Claims (1)

1. A GLOW DISCHARGE TUBE COMPRISING AN ENVELOPE FILLED WITH AN IONIZABLE MEDIUM AND ANODE AND CATHODE ELECTRODES DISPOSED THEREIN, SAID CATHODE COMPRISING A BASE HAVING AN ACTIVATING LAYER THEREON CONSISTING OF GOLD, A CESIUM-GOLD ALLOY, AND CESIUM OXIDE.
US255831A 1962-02-14 1963-02-04 Cold-cathode glow-discharge tube Expired - Lifetime US3283195A (en)

Applications Claiming Priority (1)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3467878A (en) * 1966-06-27 1969-09-16 Gen Electric Electron discharge device with arrangement for replenishing emissive material on a smooth cathode surface
US3553521A (en) * 1967-02-17 1971-01-05 Philips Corp Indirectly heated cathode for an electron discharge tube with an insulated heating element
US4275330A (en) * 1979-03-08 1981-06-23 General Electric Company Electric discharge lamp having a cathode with cesium metal oxide
DE19701816B4 (en) * 1996-01-12 2005-06-16 Epcos Ag Gas-filled discharge path and surge arrester

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1869342A (en) * 1930-06-14 1932-07-26 G M Lab Inc Photo-electric tube
US2088070A (en) * 1930-05-31 1937-07-27 Raytheon Production Corp Photoelectric tube
US2254073A (en) * 1938-03-07 1941-08-26 Emi Ltd Photoelectrically sensitive surface
US2431401A (en) * 1940-06-25 1947-11-25 Rca Corp Method of manufacturing photoelectric tubes
US2773730A (en) * 1953-12-17 1956-12-11 Tungsol Electric Inc Preparation of light sensitive surfaces

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2088070A (en) * 1930-05-31 1937-07-27 Raytheon Production Corp Photoelectric tube
US1869342A (en) * 1930-06-14 1932-07-26 G M Lab Inc Photo-electric tube
US2254073A (en) * 1938-03-07 1941-08-26 Emi Ltd Photoelectrically sensitive surface
US2431401A (en) * 1940-06-25 1947-11-25 Rca Corp Method of manufacturing photoelectric tubes
US2773730A (en) * 1953-12-17 1956-12-11 Tungsol Electric Inc Preparation of light sensitive surfaces

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3467878A (en) * 1966-06-27 1969-09-16 Gen Electric Electron discharge device with arrangement for replenishing emissive material on a smooth cathode surface
US3553521A (en) * 1967-02-17 1971-01-05 Philips Corp Indirectly heated cathode for an electron discharge tube with an insulated heating element
US4275330A (en) * 1979-03-08 1981-06-23 General Electric Company Electric discharge lamp having a cathode with cesium metal oxide
DE19701816B4 (en) * 1996-01-12 2005-06-16 Epcos Ag Gas-filled discharge path and surge arrester

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