US2351616A - Electric discharge device - Google Patents

Electric discharge device Download PDF

Info

Publication number
US2351616A
US2351616A US439896A US43989642A US2351616A US 2351616 A US2351616 A US 2351616A US 439896 A US439896 A US 439896A US 43989642 A US43989642 A US 43989642A US 2351616 A US2351616 A US 2351616A
Authority
US
United States
Prior art keywords
discharge
disc
thermionic
envelope
starting
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
US439896A
Other languages
English (en)
Inventor
Walter J Karash
Lemmers Eugene
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
Priority to FR961336D priority Critical patent/FR961336A/fr
Application filed by General Electric Co filed Critical General Electric Co
Priority to US439896A priority patent/US2351616A/en
Priority to GB6140/43A priority patent/GB566300A/en
Application granted granted Critical
Publication of US2351616A publication Critical patent/US2351616A/en
Priority to ES0178779A priority patent/ES178779A1/es
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01J61/06—Main electrodes
    • H01J61/067—Main electrodes for low-pressure discharge lamps
    • H01J61/0672—Main electrodes for low-pressure discharge lamps characterised by the construction of the electrode
    • 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
    • Y10S315/00—Electric lamp and discharge devices: systems
    • Y10S315/05—Starting and operating circuit for fluorescent lamp

Definitions

  • This invention relates to electric discharge devices, and is useful in devices producing radiation for various purposes.
  • the invention facilitates the operation of discharge devices, makes it possible to dispense with certain usual accessories, and also affords means of increasing the radiant or luminous output. It is particularly adapted for positive column discharge devices characterized by low operating pressure and a diffuse discharge, and is hereinafter explained with reference to fluorescent lamps or tubes of this character. It has proved very advantageous with respect to the starting of such lamps.
  • the early fluorescent lamp were of cold-startin type, having activated electrodes or cathodes at their ends which were heated only by the discharge between them, as exemplified by U. S.
  • Patent 2,114,842 to Inman Such lamps were somewhat subject to blackening by deposits of material thrown off (whether vaporized or sputtered) from their cathodes during the starting.
  • the electron emission from the hot electrode (s) when functio'ningas cathode (s) lowers the voltage drop and reduces the severity of ion bombardment during starting, and likewise reduces the tendency toward sputtering of cathode material.
  • these hot-starting fluorescent lamps have the disadvantage of requiring extra wiring and starting devices to enable them to be preheated and then started as described. Automatic starter of this character are themselves liable to derangement, which results in putting out of service the lamps with which they are associated, and requires troublesome replacements, besides tending to discredit the lamps themselves.
  • Positive column discharge devices include fluorescent lamps. of that type
  • this sequence of cathodic glow, dark space, and positive column glow likewise'takes place from opposite ends of the device alternately; but by persistence of vision,
  • the Faraday dark space phenomenon is due to an excess of positive ions in the region, which reduce the negative charge and field strength there, so that the voltage gradient across this space does not maintain the electron velocity at a level suiflcient to produce luminous or other radiation,-such as the 2537 A. line of mercury vapor that is mainly relied 'on to excite theluminescent materials or phosphors in ordinary fluorescent lamps.
  • the region of the Faraday dark space is externally more or less deficient in luminosity in the cas of fluorescent positive column lamps coated with phosphors, as well as in the case of non-fluorescent discharge lamps. In all discharge tubes, therefore, the Faradaydark' space represents an essentially ineffective fraction of the tube length.
  • the invention also permits of virtually abolishing or greatly ameliorating the Faraday dark space phenomenon, thus increasing the useful radiation from the device.
  • Fig. 1 is a tilted side view of a positive column electric discharge tube embodying the invention 7 in a form suitable for a fluorescent lamp,a midportion of the device being broken out and omitted to permit the drawing to be made on a larger b I scale, and suitable circuit connections for the device being diagrammatically shown.
  • Fig. 2 is a tilted side view of the end portion of a similar discharge tube, showing a modification; and Fig. 3 is a circuit diagram for the modification illustrated in Fig. 2.
  • the discharge device comprises an envelope tube III with electrodes II at its opposite ends, each of which acts as cath-- ode and anode alternately, during successive half cycles, whenthe device is operated on A. C., and is connected by current leads l2, l2 to the contact terminals
  • the electrodes II are spaced apart lengthwise of theenvelopetube I. sufliciently phosphor 5 on the cylindrical tube wall.
  • the cathodes II are connected (through a lead I2 and terminal ll of each, and through an external circuit l1, l1) across the secondary of a step-up leakage-reactance autotransformer T, whose primary is connected across the A. C. power-supply circuit P.
  • a transformer T connected in this manner gives a sufllciently high open-circuit voltage for starting the discharge, and a suitably lower operating voltage when discharge current is drawn from it after starting.
  • any other suitable current supply and discharge-starting circuit means may be employed to produce discharge-initiating voltage between the electrodes I while they are cold,
  • each cathode comprises a thermionic cathode member 2
  • may be ac: tivated with refractory oxides for more abundant emission of electrons.
  • discs oi polygonal or other non-circular outlines might also be used, and might-be rather more eillcient than a circular disc if the tube "were of correspondingnon-circular cross-section.
  • disc 22 is imperforate as shown, nor even of sheet metal: on the contrary, a disc pierced with a multitude of small holes (e. g., about 1 inch in diameter), or of wire mesh (e. g., wires of 10 mil diameter 1 inch apart both ways) has been found just as eifective, as regards both cold starting and amelioration of the Faraday dark space.
  • wire mesh or other perforate constructions have not shown any advantages beyond the obvious structural ones, such as lightness and economy of metal.
  • an electrode disc 22 and other parts proportioned and arranged as hereinafter indicated at least as close to the other electrode of the device as front of the self-heating thermionic member 2
  • This part 22 is illustrated and generally referred to as a flat disc, since that is the most convenient form for it commercially, though by no means the only practicable form.
  • the disc 22 is shown of suflicient size to obstruct the direct discharge path and largely occlude the tube Ill, and is fairly close to the thermionic member 2
  • the disc 22 may be mounted across the envelope III by means of a support wire 22 welded to it and to one of the leads l2, l2.
  • of a device with cathodes ll of this character at both ends is heated by resistance heating on both the positive and the negative A. C. half-cycles, while on the positive or anode half-cycles there is substantially no discharge to either member 2
  • is heated to efiective emission by the energy that it receives from the discharge current under these conditions.
  • each cathode may have a coil 2
  • may be activated in the usual way with a mixture of refractory oxides such as commonly used for cathode coils of fluorescent lamps of similar wattage.
  • Each electrode disc 22 may be a flat disc of sheet nickel 20 mils thick and 1 inch in diameter, and may be mounted coaxial with the tube l0 about inch in front of the coil 2
  • the electrode disc 22 When suitably placed and proportioned, the electrode disc 22 (whether integral 'as in Fig. 1, or divided as in Fig. 2) produces several bene- Not only is its position such that it would shield the tube wall III in front of it from any particles of material that "might be thrown off from the thermionic member 2
  • the action of the electrode disc 22 appears to be that it takes discharge current at starting without being materially affected by the concomitant positive ion bombardment, owing to its very large surface area as compared with the fine thermionic cathode member 2
  • the discharge current By taking a large part of the discharge current during starting, it lowers the voltage in the tube and the velocity of such ions as do reach the member 2
  • the discharge to the disc 22 has produced abundance of ions in the tube, however, the discharge shifts over from the disc to the thermionic member 2
  • the disc 22 does not heat up sufficiently to become emissive, owing to its relatively large size and mass. It is difficult to assess the benefit amongst these several factors. or to be sure that there is no other action of the" disc 22 which may be more or less responsible; but therexis no doubt that the disc'does prevent sputtering of the thermionic member .2
  • the disc 22 is effective by trapping out and eliminating the causative surplus of positive ions (wholly or partially) from. the region(s) that would otherwise be dark, without shading or blanketing apprecia-.
  • the disc 22 Being at a negative potential relative to the discharge at the point where it is situated, the disc 22 can be highly effective in collecting positive ions. Without impairing the desired even distribution of the discharge in the tube III, the disc 22 must be of relatively small thickness, in order that the discharge may spread out around the barrier offered by the disc 22, rather than canalize itself in one single path of least resistance, or jump around spasmodically over a variety of paths. In
  • any thickness of the disc 22 consistent with desirable lightness will answer; Discs about 30 mils thick are satisfactory inl'a tube'of the dimensions above indicated operating on current up to 0.5 ampere, though for higher currents. the disc should be thinner; 1
  • a disc 22 of any relative size at all comparable to those shown in the drawing will produce some beneficial effects, as regards both cold starting and the Faraday dark space, if it is located in front 'of the thermionic member 2
  • a disc of suitable size properly placed is effective to reduce or virtually eliminate the Fara- .day dark space for current densities over a considerable range; e. g., from about 0.2 ampere to about 0.5 ampere for the 1% inch tube hereinbefore referred to.
  • a disc 22 does not affect the Faraday dark space if it is locatedon the outer boundary of this dark space, remote from the thermionic member 2
  • the disc 22 For a tube such as mentionedabove, it is found advantageous to place the disc 22 about /4 inch from the cathode member 22, or even closer.
  • is where the flat disc face and the member 2
  • a disc 22 that is inch in diameter will reduce the dark space in a tube ll of 1% inches internal diameter to a minor fraction of its normal extent lengthwise oi' the tube, if it is well placed; a disc 1 inch in diamter will reduce the dark space to look like a mere dark line across the tube, only somewhat thicker to the eye than the disc itself; a disc still larger than this produces no better eflect. but does tend, on the other hand, to reduce the discharge current in the device for a given discharge voltage. From this it is to be concluded that the maximum benefit as regards reduction of the dark space is obtained with a disc whose projected area is about half the internal crosssectlonal area of the discharge envelope II, more or less, or rather less.
  • a cold-starting positive column electric discharge device characterized by low pressure and a difluse discharge therein during operation, said device comprising a discharge envelope with an ionizable operating atmosphere therein, and
  • oneof said electrodes which functions as cathode, comprising a selfheating thermionic member so flne as to be heatharge, and also comprising an electrode disc electrically connected to said thermionic member and mounted across the envelope in front of said member,
  • a cold-starting positive column electric discharge device characterized by low pressure and a diffuse discharge therein during operation, said device comprising a discharge envelope with an ionizable operating atmosphere therein, and coacting discharge electrodes in said envelope spaced apart to provide for a positive column discharge between them; one of said electrodes, which functions as cathode, comprising a self-heating thermionic member so fine as to be heated to eflective emission by the discharge, and also comprising an electrode disc electrically connected to said thermionic member and mounted across the envelope in front of said member, within substantially the inner boundary of where the Faraday dark space would otherwise be, and occupying as much as approximately half the cross-sectional area of the envelope where it is located.
  • a cold-starting positive columnelectric discharge device characterized by low pressure and a diffuse discharge therein during operation, said device comprising a discharge envelope with an ionizable operating atmosphere therein, and coacting discharge electrodes in said envelope spaced apart to provide for a positive column discharge between them; one of said electrodes, which functions as cathode, comprising a self-heating thermionic member so fine as to be heated to effective emission by the discharge, and having in operation only a single current supply connection, and also comprising an electrode disc electrically connected to said current supply connection only through said thermionic member and mounted across the envelope in front of said member, and of such ample surface area, as compared with the cross-section of the envelope where it is located and with the thermionic member, that no substantial sputtering from said member occurs during starting.
  • a positive column electric discharge device characterized by low pressure and a diil'use discharge therein during operation, said device comprising a discharge envelope with an ionizable operating atmosphere therein, and coacting discharge electrodes in said envelope spaced apart to provide for a positive column discharge between them, and functioning alternately as anode and as cathode during A.
  • At least one of said electrodes comprising both a thermionic member having in operation only a current supply connection to one point thereing of such ample surface area, as compared with the thermionic member and with the envelope cross-section where the disc is located, that the discharge goes to the thermionic member and to the disc, respectively, on the cathode and anode half-cyclesof the discharge, and there is substantially no discharge ,to the thermionic member during the anode half-cycles, while the discharge current flows in the thermionic memher during both of these half-cycles; and said thermionic member being proportioned to be beated to eflective emission by the energy which it receives from the discharge current.
  • a cold-starting positive column electric discharge device characterized by low pressure and a diffuse discharge therein during operation, said device comprising a discharge envelope with an ionizable operating atmosphere therein, and co acting discharge electrodes in said envelope spaced apart to provide for a positive column discharge between them; one of said electrodes, which functions as cathode, comprising a.
  • self-heating thermionic member so fine as to be heated to effective emission by the discharge, and having current leads to both ends thereof only one of which is a current supply connection in operation, and also comprising an electrode disc mounted across the envelope in front of said thermionic member and divided into segments each of which is connected to one of said leads independently of said thermionic member, said electrode disc segments having such ample surface area, as compared with the cross-section of the envelope where they are located and with the thermionic member, that no substantial sputtering from said member occurs during starting.
  • a positive column electric discharge device characterized by low pressure and a diffuse discharge therein during operation, said device comprising a discharge envelope with an ionizable operating atmosphere therein, and coacting discharge electrodes spaced apart in said envelope to provide for a positive column discharge between them, one of said electrodes comprising a self-heating thermionic cathode member so fine as to be heated to effective emission by the discharge: of current supply and discharge-starting circuit means connected to said electrodes for producing discharge-initiating voltage between them while they are cold, followed by lower discharge-maintaining voltage; and an electrode disc electrically connected to said thermionic member and mounted across the envelope in front of said member substantially within the outer boundary of where the Faraday dark space would otherwise be, and of such ample surface area, as compared with the cross-section of the envelope where it is located and with the thermionic member, that no substantial sputtering from the latter occurs during cold starting as aforesaid, while the Faraday dark space during subsequent operation is substantially
  • a positive column electric discharge device characterized by low pressure and a diffuse discharge therein during operation, said device comprising a discharge envelope with an ionizable operating atmosphere therein, and coacting discharge electrodes spaced apart in said envelope to provide for a positive column discharge between them, one of said electrodes member so fine as to be heated to eflective emission by the discharge; of current supply and discharge-starting circuit means connected to said electrodes for producing dischargeeinitiating voltage between them while they are cold, followed by lower discharge-maintaining voltage, through a single current supply connection only; and an electrode disc mounted across the envelope in front of said thermionic member substantially within the outer boundary of where the Faraday dark space would otherwise be and electrically connected to said current supply connection only through said member, and of such ample surface area, as compared with the cross-section of the envelope where it is located and with the thermionic member, that no substantial sputtering from the latter occurs during cold starting as aforesaid, while the Faraday dark space during
  • a positive column electric discharge device characterized by low pressure and a diffuse discharge therein during operation, said device comprising a discharge envelope with an ionizable operating atmosphere therein, and coacting discharge electrodes spaced apart in said envelope to provide for a positive column discharge between them, one of said electrodes comprising a self-heating thermionic cathode member so fine as to be heated to efiective emission by the discharge; of current supply and discharge-starting circuit means connected to said electrodes for producing discharge-initiating voltage between them while they are cold, followed by lower discharge-maintaining voltage, through a single current supply connection only; and an electrode disc mounted across the envelope in front 0!
  • said thermionic member substantially within the outer boundary of where the Faraday dark space would otherwise be and divided into segments one of which only is elec- H trically connected to said current supply connection through said member, said electrod disc segments having such ample surface area, as compared with the cross-section of the envelope where they are located and with the thermionic member, that no substantial sputtering from the latter occurs during cold starting as aforesaid, while the Faraday dark space during subsequent operation is substantially abolished.
  • a cold-starting positive column electric discharge device characterized by low pressure and a diffuse discharge therein during operation, said device comprising a discharge envelope with an ionizable operating atmosphere therein, and coacting discharge electrodes in said envelope spaced apart to provide for a positive column discharge between them; one of said electrodes, which functions as cathode, comprising a selfheating activated thermionic member so fine as to'be heated to efiective emission by the discharge, and also comprising an electrode electrically connected to said thermionic'member and mounted across the envelope in front of said member, substantially within the outer boundary of where the Faraday dark space would otherwise be, and cocupying as much as approximately half the crosssectional area of the envelope where it is located.

Landscapes

  • Discharge Lamps And Accessories Thereof (AREA)
  • Discharge Lamp (AREA)
US439896A 1942-04-21 1942-04-21 Electric discharge device Expired - Lifetime US2351616A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
FR961336D FR961336A (xx) 1942-04-21
US439896A US2351616A (en) 1942-04-21 1942-04-21 Electric discharge device
GB6140/43A GB566300A (en) 1942-04-21 1943-04-16 Improvements in and relating to electric discharge devices
ES0178779A ES178779A1 (es) 1942-04-21 1947-07-04 Un tubo de descarga eléctrica

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US439896A US2351616A (en) 1942-04-21 1942-04-21 Electric discharge device

Publications (1)

Publication Number Publication Date
US2351616A true US2351616A (en) 1944-06-20

Family

ID=23746578

Family Applications (1)

Application Number Title Priority Date Filing Date
US439896A Expired - Lifetime US2351616A (en) 1942-04-21 1942-04-21 Electric discharge device

Country Status (4)

Country Link
US (1) US2351616A (xx)
ES (1) ES178779A1 (xx)
FR (1) FR961336A (xx)
GB (1) GB566300A (xx)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2438579A (en) * 1942-06-16 1948-03-30 Gen Electric Electric gas discharge tube
US2446152A (en) * 1946-05-29 1948-07-27 Sylvania Electric Prod Electrical apparatus for gaseous discharge devices
US2464643A (en) * 1945-04-05 1949-03-15 Eugene R Kulka Holder for gaseous discharge lamps
US2512282A (en) * 1945-08-17 1950-06-20 Gen Electric Electric discharge lamp
US2561898A (en) * 1948-05-13 1951-07-24 Gen Electric Electric discharge lamp
US2757318A (en) * 1953-05-18 1956-07-31 Gen Electric Rectifying circuit for discharge lamps
DE966001C (de) * 1950-05-20 1957-07-04 Pintsch Electro G M B H Dampf- oder/und gasgefuellte Entladungslampe, insbesondere Leuchtstoffroehre
US3039022A (en) * 1954-11-05 1962-06-12 Arcy Ellis W D Motion picture projector

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2438579A (en) * 1942-06-16 1948-03-30 Gen Electric Electric gas discharge tube
US2464643A (en) * 1945-04-05 1949-03-15 Eugene R Kulka Holder for gaseous discharge lamps
US2512282A (en) * 1945-08-17 1950-06-20 Gen Electric Electric discharge lamp
US2446152A (en) * 1946-05-29 1948-07-27 Sylvania Electric Prod Electrical apparatus for gaseous discharge devices
US2561898A (en) * 1948-05-13 1951-07-24 Gen Electric Electric discharge lamp
DE966001C (de) * 1950-05-20 1957-07-04 Pintsch Electro G M B H Dampf- oder/und gasgefuellte Entladungslampe, insbesondere Leuchtstoffroehre
US2757318A (en) * 1953-05-18 1956-07-31 Gen Electric Rectifying circuit for discharge lamps
US3039022A (en) * 1954-11-05 1962-06-12 Arcy Ellis W D Motion picture projector

Also Published As

Publication number Publication date
ES178779A1 (es) 1947-09-01
GB566300A (en) 1944-12-21
FR961336A (xx) 1950-05-10

Similar Documents

Publication Publication Date Title
US3121184A (en) Discharge lamp with cathode shields
US2262177A (en) Lighting and radiating tube
US2351616A (en) Electric discharge device
US2530990A (en) Electric discharge device
US2549355A (en) Fluorescent lamp
US4461970A (en) Shielded hollow cathode electrode for fluorescent lamp
US4879493A (en) Low-pressure discharge lamp
US2429118A (en) Electrode for fluorescent tubes
US2733371A (en) Internally conducttvely coated
US2724070A (en) Cathode coating for electrical discharge devices and method for making the same
US1990175A (en) Gaseous electric discharge device
US2241362A (en) Electron emissive cathode
US2185189A (en) Gaseous discharge tube
US3013175A (en) High output discharge lamp
US3029359A (en) Thermionic electrode for discharge lamps
US2488716A (en) Electric high-pressure discharge tube
US3328622A (en) Electric discharge device having primary and secondary electrodes
US3069580A (en) Fluorescent lamp
US2313646A (en) Gaseous discharge lamp
US2241345A (en) Electron emissive cathode
US3069581A (en) Low pressure discharge lamp
US2094668A (en) Electric metal vapor lighting tube
US2329126A (en) Electric discharge device and electrode therefor
US2496374A (en) Tubular electric lamp
US2009211A (en) Gaseous electric discharge device