US2898502A - Cold cathode electric discharge tubes - Google Patents

Cold cathode electric discharge tubes Download PDF

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Publication number
US2898502A
US2898502A US582596A US58259656A US2898502A US 2898502 A US2898502 A US 2898502A US 582596 A US582596 A US 582596A US 58259656 A US58259656 A US 58259656A US 2898502 A US2898502 A US 2898502A
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United States
Prior art keywords
discharge
gap
cathode
tube
envelope
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
US582596A
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English (en)
Inventor
Beck Arnold Hugh William
Jackson Thomas Meirion
Lytollis John
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.)
International Standard Electric Corp
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International Standard Electric Corp
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Filing date
Publication date
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
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Publication of US2898502A publication Critical patent/US2898502A/en
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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
    • H01J17/02—Details
    • H01J17/30—Igniting arrangements

Definitions

  • One method commonly used in glow discharge tubes to eliminate the statistical delay of firing is that of photoelectric priming, in which light from a source external or internal to the tube liberates photo-electrons from the cathode of the discharge gap in question.
  • the efliciency of this method depends on the wavelength of the irradiating source and its relation to the photoelectric threshold of the cathode material.
  • the work function of the metal is so high that irradiation by ultra-violet light is required, which light is so attenuated by the glasses normally used for tube envelopcs, that the light source must be placed inside the envelope; an appreciable amount of power is then required for its production, While precautions may have to be taken to prevent excessive ionisation which would unduly lower the striking voltage of the discharge gap.
  • an auxiliary discharge gap is arranged in such manner that, not only is there little danger of encountering the difficulties just mentioned, but it serves the further function of controlling the potential at the inner envelope wall of a discharge tube.
  • a cold cathode gas-filled electric glow discharge tube comprising an envelope of insulating material enclosing discharge gap electrodes spaced therefrom, a conductive coating on the inside of the envelope, and a separate lead connected to the coating for setting up a discharge through the gas between the coating or the said lead and one of the aforementioned discharge gap electrodes or a lead connected thereto.
  • Fig. 1 shows a front elevational cross-section through a tube embodying the invention
  • Fig. 2 shows a side elevation, in partial section, of the tube of Fig. 1;
  • Fig. 3 shows a typical circuit using a pair of the above tubes
  • FIG. 4 is a graph showing the voltage-current characteristic of the auxiliary discharge gap in the tubes of Figs. 1 and 2.
  • the tube of Figs. 1 and 2 has a glass envelope 1 formed at one end into'a press 2 through which are sealed electrodeleads 3.
  • a cathode 4 mounted on respective ones of the leads 3 are a cathode 4 in the form of a flat plate, and two pairs of anode rods, 5 and 6, disposed symmetrically with respect to the cathode, the rods of each pair being disthe cathode plate.
  • the lead 7 carrying the cathode is surrounded within and above the press 2 by a glass head 8 sealed into the press and, immediately below the cathode plate, by a glass sleeve 9.
  • Each pair of anodev rods is formed of a single length of rod bent into the shape of a U.
  • a portion of the interior of the glass envelope is coated with silver, as indicated at 10 in Fig. 2.
  • a metal ring 11 (Fig. -l-) is a spring fit against the coating 10 and surrounds the upper ends of the leads carrying the anode rod
  • the cathode plate 4 is formed of molybdenum and the envelope is filled with helium at a pressure of 60 mm. of mercury. After processing, a film,
  • a pair of tubes as justdescribed is indicated at 13 and 13.
  • the electrodes of these tubes are indicated by the same reference numerals as in Figs. 1 and 2. Except for the auxiliary priming gap the circuit and its operation is essentially the same as that described with reference to Fig. 2 of the aforementioned patent.
  • the transformers 14 and 15- couplethe circuit with an audio frequency line. In the presence of glow dischargebetween the cathodes 4 and the respective anodes Sand 6, a low-loss path-isestablished between-the centre-tapped windings of transformers 14 andlSthrough the gap between each set of anodes.
  • cathode 4 of each tube is connected to earth through a choke 16 and rectifier 17 and each cathode is also connected through aresistor 18 to a pulse input terminal 19.
  • a source of positive supply voltage is connected to terminals 20 from which current is fed through-therespective transformer windings to the pairs ofanodesthereafter maintained by the supply source connected to terminal-19.
  • the speech path is broken, when desired, by raising the potential of both cathodes 4 and/ or lowering the potential of all anodes so that the anode-cathode voltage isheld below the maintaining potential long enough for deionisation of the gas to prevent refiring on re-establishing the maintaining voltage.
  • each ring 11, and hence the associated envelope coating 10 is connected through a high value resistor 24 to a source of negative potential applied to terminal 25. Care must be taken that the stray capacity across this circuit is kept to a minimum so that a continuous discharge takes place between each ring- 11 and the adjacent lead supporting the anode rods 6; It ispreferred that this priming discharge pass to the pair of anodes to which the circuit-making starting pulse is applied.
  • this priming discharge pass to the pair of anodes to which the circuit-making starting pulse is applied.
  • resistors 24 are each 50 megohms and in a typical tube, the priming current to ring 11 is one rnicroampere, the voltage drop across the auxiliary discharge gap being 260.
  • the maintaining voltage is about 154.
  • the discharge is sub-normal, i.e. as the discharge current is decreased the interelectrode voltage must be increased to maintain the discharge.
  • the operating point of 260 volts, 1 ,uA. is seen to be Well in the sub-normal discharge region. At this discharge current the potential of the coating 'is 60 volts.
  • a cold cathode electric discharge tube comprising an envelope of insulating material filled with an ionizable gas, a plurality of electrodes within said envelope defining a main discharge gap therebetween, conductive current carrying means for carrying space discharge current to given of said main gap electrodes, a conductive coating on the inside of said envelope and defining a priming discharge gap with said conductive carrying means, and additional current carrying means coupled to saidcoating for carrying space discharge current to said coating, said primary, discharge gap adapted to provide an ionization coupling with said main discharge 7 gap thereby to eliminate statistical delay in firing of said main gap upon application of current to said first current carrying means.
  • a glow discharge tube comprising a main 7 cathode in the form of a flat plate and two pairs of anode rods symmetrically disposed with respect to the said plate,
  • the rods of each said pair being disposed symmetrically one on each side of and parallel to the plate, said separate lead comprising a resilient metal ring contacting the said conductive coating on the inside of the envelope, the said cathode and the anode rods being mounted slightly eccentrically with respect to the said ring so that one of the said anode rods is closer to the said ring than any other discharge gap electrode.
  • a glow discharge tube in which each pair of anode rods is mounted on a lead sealed through a glass press, the said cathode is mounted on a rod sealed through the said press in substantially the plane containing the said further rods and the said ring is positioned about the said further rods.
  • a glow discharge tube is defined between a main cathode in the form of a flat plate and two pairs of anode rods, each pair mounted on a separate connecting lead symmetrically disposed with respect to the said plate, the rods of each said pair being disposed symmetrically, one on each side of and parallel to the plate, said separate lead comprising a resilient metal ringcontacting the said conductive coating on the inside of the envelope, the said cathode and 3 the anode rods being mounted slightly eccentrically with respect to the said ring so that one of the connecting leads of said anode'rods is closer to the said ring than another discharge gap electrode.
  • a circuit arrangement comprising a glow discharge tube according to claim 2, in which the statistical delay of firing of a gap or gaps, between the said discharge gap electrodes, is eliminated by passage of a steady sub-normal discharge from said metal ring.

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  • Lasers (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Gas-Filled Discharge Tubes (AREA)
US582596A 1955-05-13 1956-05-03 Cold cathode electric discharge tubes Expired - Lifetime US2898502A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB342296X 1955-05-13

Publications (1)

Publication Number Publication Date
US2898502A true US2898502A (en) 1959-08-04

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ID=10363013

Family Applications (1)

Application Number Title Priority Date Filing Date
US582596A Expired - Lifetime US2898502A (en) 1955-05-13 1956-05-03 Cold cathode electric discharge tubes

Country Status (5)

Country Link
US (1) US2898502A (de)
BE (1) BE547792A (de)
CH (1) CH342296A (de)
FR (1) FR69995E (de)
GB (1) GB778433A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3093767A (en) * 1961-05-10 1963-06-11 Gen Electric Gas generating switching tube

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2089677A (en) * 1932-04-29 1937-08-10 Kramolin Leon Ladislaus Von Devices for tracing the movements of objects
US2095930A (en) * 1932-12-24 1937-10-12 Houtermans Fritz Georg Electric discharge tube
US2275242A (en) * 1939-10-07 1942-03-03 Fides Gmbh Glow discharge tube
US2291965A (en) * 1939-08-30 1942-08-04 Gen Electric Electrical discharge device
US2654042A (en) * 1949-07-29 1953-09-29 Gen Electric Integrally capacitively ballasted discharge lamp

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2089677A (en) * 1932-04-29 1937-08-10 Kramolin Leon Ladislaus Von Devices for tracing the movements of objects
US2095930A (en) * 1932-12-24 1937-10-12 Houtermans Fritz Georg Electric discharge tube
US2291965A (en) * 1939-08-30 1942-08-04 Gen Electric Electrical discharge device
US2275242A (en) * 1939-10-07 1942-03-03 Fides Gmbh Glow discharge tube
US2654042A (en) * 1949-07-29 1953-09-29 Gen Electric Integrally capacitively ballasted discharge lamp

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3093767A (en) * 1961-05-10 1963-06-11 Gen Electric Gas generating switching tube

Also Published As

Publication number Publication date
CH342296A (de) 1959-11-15
FR69995E (fr) 1959-01-30
GB778433A (en) 1957-07-10
BE547792A (de)

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