US2030521A - Electric discharge tube - Google Patents

Electric discharge tube Download PDF

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Publication number
US2030521A
US2030521A US744453D US74445334D US2030521A US 2030521 A US2030521 A US 2030521A US 744453 D US744453 D US 744453D US 74445334 D US74445334 D US 74445334D US 2030521 A US2030521 A US 2030521A
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US
United States
Prior art keywords
discharge
metal
vapour
cathode
vessel
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
Application number
US744453D
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English (en)
Inventor
Hertz Gustav Ludwig
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Application granted granted Critical
Publication of US2030521A publication Critical patent/US2030521A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/70—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/04—Electrodes; Screens; Shields

Definitions

  • the invention has reference to a gasfilled electric discharge tube and has for its object the construction of a discharge tube of this kind, in which the light radiated in consequence of the electric discharge, principally shows the spectrum of a metal vapour, so that the spectrum of any metal can be examined and also light of any desired colour for illumination or other purposes can be obtained.
  • the discharge tube according to the invention is provided with a cathode, an anode, a gaseous filling consisting of one or more electro-positive gases and a device for developing metal vapour the density of which in the path of discharge attains such value that the light radiated as a consequence of the discharge substantially shows the spectrum of the vapour.
  • the rare gases may preferably be used for the gaseous filling; instead of the vapour of a single metal also a mixture of vapours maybe developed.
  • path of discharge that part of the interior of the discharge .tube is meant in which the electric discharge is chiefly produced.
  • the discharge may be an independent one, for example an independent glow discharge; in this case the metal vapour is preferably developed in the positive column of the discharge.
  • the discharge tube is preferably provided with an incandescent cathode.
  • a so-called oxide-cathode may be used; it may be constituted by a metal body that is coated on the active surface with a substance which easily emits electrons, and is suspended from one or more heating wires which make metallic contact with the said body and are capable of heating it to the required temperature.
  • means may be provided in order to prevent the volatilized metal from precipitating on the glass wall.
  • the device for developing the metal vapour may be used as the anode; according to the invention there may also be arranged between the cathode and the vessel developing the metal vapour a metal plate that serves as anode and has an opening provided with a grid for letting through the electrons emitted by the cathode.
  • Figure 1 shows a discharge tube, according to l the invention, with its connections.
  • Figure 2 illustrates a modified construction of the discharge tube according to the invention, also with its connections.
  • the device for developing the metal vapour acts as an anode.
  • the constructions shown in the Figures 2 and 3 are identical except that the means provided to prevent the forming of a precipitate on the glass wall differ in the two cases.
  • Fig. 5 represents the cathode structure of the discharge devices of Figs. 2 and 3 on an enlarged scale.
  • the discharge tube according to Figure 1 con- .sists of a vessel I of glass or similar material in which stems 2 and 2 carrying electrodes are sealed.
  • the stem 2 carries a cathode 3 and in the clamped portion 4 of the stem 2 leading-in wires 9 for the cathode are sealed.
  • the stem 2 also carries a metal plate 5 having a central opening 6 on which a grid 22 is placed. A leading-in wire for the metal plate 5 that acts as an anode, is sealed in the clamped portion 4.
  • a battery I is connected to a potentiometer 8, one end of which is connected to the leading-in wire 9 of the cathode 3 and along which the contacts I0 and I I which are in connection respectively with the other end of the cathode 3 and with the anode 5, are slidable.
  • the temperature of the filament and the voltage of the anode can be regulated by sliding respectively the contact Ill and the contact I I.
  • the heating wires l3 and 14 are preferably of a material having a high specific resistance; for example nickel-chromium may be used.
  • the dimensions of the wires I3 and I4 are such that it is not necessary to heat the wire to such an extent that detrimental results occur such as for example, the fusing of the wire.
  • the wires I3 and I4 have a small length.
  • This device for heating the vessel l2 to the required temperature offers the advantages that a high temperature can easily be attained, that the required current can be feeble and that the thermal efiiciency is rather high.
  • the conductive wires 15 and I6 may, as usual, be of nickel.
  • the cathode 3 is preferably an oxide cathode, namely a. wire coated with a metal oxide that emits electrons at a relatively low temperature, for example with oxide of barium.
  • the gaseous filling in the tube 1 consists of an electro-positive gas, preferably a. rare gas or a mixture of rare gases.
  • the pressure of the rare gas must be relatively low, for example of the order of magnitude of one centimeter or less in order that the gas shall be translucent for the spectrum radiated by the ionized vapor in the discharge.
  • the cathode 3 During the operation of the tube the cathode 3 emits electrons which pass through the grid 22 at a certain velocity in consequence of the electric field between the cathode and the anode.
  • the vessel I2 is heated to the required temperature so that the metal vapour is developed, the molecules of which move amidst the molecules of the rare gas.
  • the molecules of the vapour will be excited or ionized by the electrons, so that light is radiated having the spectrum of metal vapour.
  • the rare gaseous filling chiefly serves to prevent the molecules of the vapour from precipitating immediately on the colder parts around the vessel l2.
  • the plate 5, too can retain the molecules of the vapour so that they do not precipitate on the glass wall of the tube.
  • the metal vapour has only in the path of discharge such density that the light radiated in consequence of the discharge, principally shows the spectrum of the vapour.
  • the temperature is low and consequently the partial pressure of the metal vapour is practically equal to zero.
  • the discharge tube according to the invention difiers from the known metal vapour lamps as in the latter the discharge is so intensive and consequently the temperature in the tube so high, that the whole tube is filled with the vapour.
  • the presence of the metal vapour is necessary for initiating the discharge, but in tubes according to the invention the discharge may also pass without depending on the vapour; when however vapour of the required density is developed, its molecules are influenced by the discharge so that light is radiated showing the spectrum of the vapour.
  • the discharge tube shown in the Figures Sand 4 is similar to the one shown in Figure 2; only other means are provided to prevent the metal vapour from precipitating on the glass wall.
  • the cathodes shown in' the Figures 2 and 3 are so called equipotential cathodes", all points of the surface having the same potential.
  • a device for developing metal vapor which has in the path of the discharge a density whereby the light radiated substantiallyshows the spectrum of the vapor, and a screen surrounding the path of the discharge for preventing the volatilized metal from precipitating on the tube wall, said screen consisting of a number of metal plates lying in difierent planes intersecting the axis of the path of the discharge.
  • said means for holding the substance to be vaporized being mounted closely adjacent said discharge means to develop vapor in the discharge at such a high pressure relative to the pressure of the gas filling that the light radiated from the discharge device shows the spectrum of the vapor.
  • An electric discharge device comprising spaced electrodes, a receptacle in the line of discharge between said electrodes, a quantity of sodium in said receptacle and an electric heating device for heating said receptacle to liberate sodium vapor in the discharge path whereby the light radiated shows the spectrum of the vapor.
  • An electric discharge lamp comprising a sealed envelope, spaced electrodes therein adapted to support an electric discharge, means for supplying metal vapor to the discharge path at such rate that the light radiated shows the spectrum of the vapor and means in said envelope for preventing deposition of the metal vapor on the portion of the envelope wall through which the light is transmitted.
  • An electric lamp comprising a light-transmitting bulb, electrodes therein including a.

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  • Hybrid Cells (AREA)
  • X-Ray Techniques (AREA)
  • Particle Accelerators (AREA)
  • Discharge Lamp (AREA)
US744453D 1923-11-20 1934-10-18 Electric discharge tube Expired - Lifetime US2030521A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR577242T 1923-11-20

Publications (1)

Publication Number Publication Date
US2030521A true US2030521A (en) 1936-02-11

Family

ID=8954593

Family Applications (1)

Application Number Title Priority Date Filing Date
US744453D Expired - Lifetime US2030521A (en) 1923-11-20 1934-10-18 Electric discharge tube

Country Status (3)

Country Link
US (1) US2030521A (fr)
FR (1) FR577242A (fr)
GB (1) GB225218A (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4866339A (en) * 1987-12-21 1989-09-12 Gte Laboratories Incorporated Beam mode fluorescent lamp

Also Published As

Publication number Publication date
GB225218A (en) 1925-09-24
FR577242A (fr) 1924-09-02

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