US2530394A - Electrode coating for discharge devices - Google Patents

Electrode coating for discharge devices Download PDF

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Publication number
US2530394A
US2530394A US752698A US75269847A US2530394A US 2530394 A US2530394 A US 2530394A US 752698 A US752698 A US 752698A US 75269847 A US75269847 A US 75269847A US 2530394 A US2530394 A US 2530394A
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US
United States
Prior art keywords
envelope
coating
electrodes
electrode
lamp
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
US752698A
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English (en)
Inventor
Erwin F Lowry
Eric L Mager
Gerald W Keilholtz
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.)
GTE Sylvania Inc
Original Assignee
Sylvania Electric Products Inc
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 BE482916D priority Critical patent/BE482916A/xx
Application filed by Sylvania Electric Products Inc filed Critical Sylvania Electric Products Inc
Priority to US752698A priority patent/US2530394A/en
Priority to FR966907D priority patent/FR966907A/fr
Priority to GB15207/48A priority patent/GB655123A/en
Priority to DES20260A priority patent/DE974434C/de
Application granted granted Critical
Publication of US2530394A publication Critical patent/US2530394A/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
    • H01J61/02—Details
    • H01J61/04—Electrodes; Screens; Shields
    • H01J61/06—Main electrodes
    • H01J61/067—Main electrodes for low-pressure discharge lamps
    • H01J61/0675—Main electrodes for low-pressure discharge lamps characterised by the material of the electrode
    • H01J61/0677—Main electrodes for low-pressure discharge lamps characterised by the material of the electrode characterised by the electron emissive material

Definitions

  • This invention relates to electric gaseous discharge devices and more particularly to fluorescent lamps and the composition of the coating material with which the lamp electrodes are provided.
  • An object of this invention is to provide an eiiicient electrode coating for electric gaseous discharge devices.
  • Another object is to provide an electrode coating which will eifect a lengthening of the life of the device in which the electrode is employed.
  • a further object is to provide an electrode coating which will enhance the lumens per watt maintenance of the device in which the electrode is employed.
  • a further oblect is to provide a new coating composition for fluorescent lamp electrodes.
  • a further object is to provide a coating composition for iluorescent lamp electrodes which will have a. beneficial eiiect in reducing various types and forms of discoloration which sometimes develop on the wall oi the lamp during'life.
  • a light-transmitting tubular envelope I. of glass or the like is coated on its inner. wall with a iluorescent material 2 such'as tungstates or silicates, for example, magnesium tungstate or zinc beryllium silicate.
  • a iluorescent material 2 such'as tungstates or silicates, for example, magnesium tungstate or zinc beryllium silicate.
  • the envelope 2 is provided, at each end, with a stem 3, through which lead wires 4 and 5 extend.
  • the outer ends of the lead wires 4 and 5 are connected topinslandloiabasewhichissecuredto the ends of the envelope l.
  • the sealed envelope is provided with a illllng of inert gas at a low pressure, such as argon at about 3 mm., and'a small quantity of mercury Il to provide mercury vapor.
  • the lamp is ordinarily operated at a mercury vapor pressure of between 1 to 20 microns.
  • the electrodes comprise a coiled lament oi tungsten wire.
  • the electrodes are usually provided with a coating of an electron-emissive material.
  • the electrode wire can be wound into a minor coil and the latter itself then wound into a major coil to form a coiled-coil with the electron-emisslve coating material illing the space within the minor coil only.
  • a fluorescent lamp electrode In the case of a fluorescent lamp electrode.
  • the electron emissive material usually coin- 2 prises an oxide oi one or more of the alkaline earth metals.
  • the alkaline earth metals are usually applied in the iorm of a carbonate which breaks down to the oxide when the lamp is processed.
  • discoloration oi' various types and forms appears on the wall oi the lamp near the ends thereof and in proximity to the electrodes. It is an object of this invention to reduce the irequency of occurrence and intensity of these discolorations.
  • Three types of discoloratlons which are aiected by the new electrode coating coinposition of our invention are, electrode spots, end bands, and multiples.
  • Electrode spots are dark gray or black spots which appear on the inner wall of the lamp near the ends thereof, and are usually found approximately opposite the electrodes.
  • End bands are rings of discoloration, usually light yellow, brownish or black, which usually extend completely around the periphery oi the inner wall of the lamp. End bands are usually deiined by a sharp edge on the side near the electrode and a diliused edge on the side near the longitudinal center of the lamp. End bands are usually round forward of the electrodes with the sharp edge located opposite the end of the positive column discharge. Multiples are narrow crescente of discoloration, usually light yellow, brownish, or black, which appear near the ends of the lamp on both sides of the electrodes, i. e., on the base side of the electrode as well as the side near the longitudinal center of the lamp. l
  • zirconium dioxide in proper amounts to the basic electron emlssive material with which the electrodes are coated will not only reduce the frequency of appearance and intensity of the above described discolorations but will also extend the useful life of the lamp and increase the lumens per watt maintenance during life.
  • the basic electron emissive material we preier to use a triple carbonate, of the alkaline earth metals, i. e., SrCO:l, BaCOa. and CaCOs.
  • a douille or single carbonate may be employed without departing from the spirit of our invention.
  • the carbonates may be prepared in any suitable manner well known in the art.
  • the triple carbonate we have found the following composition to be very satisfactory: about 35% SrCOz, about of ZrOz may vary from between about 1% t0 about 20% by weight based on the total weight oi' the carbonates to which it is added. We have found that the addition o! about 5% by weight based on the weight of the carbonates gives exceptionaliy good results.
  • Table I shows, in percent, the number of lamps. of the hundreds which were checked, which were free of any discoloration atl00, 300, and 500 hours of operation.
  • Tests A, B and C represent 40 ⁇ watt fluorescent lamps in which the electrode coating contained no ZrOz.
  • Test D about 5% ZrO-i was added to the velectrode coating material.
  • Table II shows the average L. P. W. of lamps late in life.
  • ve lamps had no ZrOa in the electrode coating
  • ilve lamps had 5% ZrOz in the electrode coating
  • ilve lamps had 10% ZrOz in the electrode coating.
  • Table III shows the time at which the lamps of Table II failed.
  • the average life of the lamps with no ZrOz in the electrode coating was about 4200-4300 hours; the first failure of the lamps with ZrOz in the electrode coating did not occur until almost 6000 hours; and the '7000 hour mark has been passed without a single failure among the five lamps with 5% ZrOz in the electrode coating material.
  • the tungsten wire illamentary electrodes of uorescent lamps are usually provided with an electron-emissive coating of the oxide of one or more of the alkaline earth metals.
  • this material is usually applied to the electrodes in the form 'of a carbonate which is later broken down to give the oxide. ⁇ For this reason, therefore, the proportions given above with reference to the amount of ZrOz which is added (1% to 20%) are based on the weight of the mixed carbonates to which the ZrO'. ⁇ is added.
  • Thefpreierential amount oi.' ZrO which has been described as about 5% by weight based on the weight of the mixed carbonates is slightly less than 5% by weight of the total batch after mixing and is slightly more than 6% oi' the total weight of the mixed oxides ilnally obtained.
  • the 10% ZrOa in Table III is based on the total weight of the mixed carbonates to which the zirconium dioxide is added. This is equivalent to about 11% of the iinal weight of the mixed oxide, the carbonate being converted to oxides during the lamp processing, as previously explained.
  • a 'coating material for electric gaseous discharge device electrodes comprising at least one oxide of an valkaline earth metal and a quantity of zirconium dioxide equal to about 6% by weight of the total weight of all the oxides.
  • a coating material for electric gaseous dis- 60 charge device electrodes comprising oxides of at least two of the alkaline earth metals and a quantity of zirconium dioxide equal to about 6% by weight of the total weight of all the oxides.
  • a coating material for electric gaseous dis- 05 charge device electrodes comprising oxides or tium and calcium and a quantity of zirconium dioxide in an amount more than about 1% but not more than 11% by weight of the total weight of all the oxides.
  • a iluorescent lamp comprising a sealed lighttransmitting envelope, a coating of iiuorescent material on the inner wall of said envelope, a quantity of mercury in said envelope, a lling of inert gas in said envelope, iilamentary electrodes in said envelope, and a coating on said electrodes, said coating comprising at least one oxide of an alkaline earth metal and a quantity of zirconium dioxidel equal to about 6% by weight of the total weight of all the oxides.
  • a fluorescent lamp comprising a sealed lighttransmitting envelope, a coating of fluorescent material on the inner wall of said envelope, a quantity oi mercury in said envelope, a iilling of inert gas in said envelope, lamentary electrodes in said envelope. and a coating on said electrodes, said coating comprising oxides of at least two of the alkaline earth metals and a quantity of zirconium dioxide equal to about 6% by weight of the total weight of all the oxides.
  • a fluorescent lamp comprising a sealed lighttransmitting envelope, a coating of iiuorescent material on the inner wall of said envelope, a quantity of mercury in said envelope, a iilling of inert gas in said envelope, illamentary electrodes in said envelope, and a coating on said electrodes, said coating comprising oxides of barium, strontium and calcium and a quantity of zirconium dioxide equal to about 6% by weight of the total weight of all the oxides.
  • a fluorescent lamp comprising a sealed lighttransmitting envelope, a coating of fluorescent material on the inner Wall of said envelope, a quantity of mercury in said envelope, a lllng of inert gas in said envelope, fllarnentary electrodes in said envelope, and a coating on said electrodes, said coating comprising at least one oxide of an alkaline earth metal and a quantity of zirconium dioxide in an amount more than about 1% but not more than 11% by weight of the total weight of all the oxides.
  • a fluorescent lamp comprising a sealed lighttransmitting envelope, a coating of iluorescent material on the inner wall of said envelope, a quantity oi' mercury in said envelope, a filling of inert gas in said envelope, iilamentary electrodes in said envelope, and a coating on said electrodes, said coating comprising oxides of at least two of the alkaline earth metals and a quantity of zirconium dioxide in an amount more than about 1% but not more than 11% by weight of the total weight of all the oxides.
  • a iiuorescent lamp comprising a sealed light-transmitting envelope, a coating of fluorescent material on the inner wall of said envelope, a quantity of mercury in said envelope, a filling of inert gas in said envelope, lamentary electrodes in said envelope, and a coating on said electrodes, said coating consisting essentially of at least one oxide of an alkaline earth metal and a quantity of zirconium dioxide in an amount more than about 1% but not more than 11% by weight of the total weight of all the oxides.
  • a iluorescent lamp comprising a sealed light-transmitting envelope, a coating of fluorescent material on the inner wall of said envelope, a quantity of mercury in said envelope, a filling of inert gas in said envelope, fllamentary electrodes in said envelope, and a coating on said electrodes, said coating consisting essentially of oxides of at least two or the alkaline earth metals ,of barium, strontium and calcium and a quantity of zirconium dioxide in an amount more than about 1% but not more than 11% by weight of the total weight of all the oxides.
  • a low-pressure iluorescent lamp comprising an elongated sealed light-transmitting envelope, a coating of uorescent material on the inner wall of said envelope, a quantity of mercury in said envelopes, a fllamentary electrode of coiled tungsten wire at each end of said envelope, and an electron-emissive material carried by said electrode and comprising at least one oxide of an al kaline earth metal and a quantity of zirconium dioxide in an amount between about 1% and 11% by weight of the total weight of all the oxides carried by said electrode.
  • a fluorescent lamp comprising a sealed light-transmitting envelope, a coating of fluorescent material on the inner wall of said envelope, a quantity of mercury of said envelope, a filling of inert gas in said envelope, lamentary electrodes in said envelope, and a coating on said electrodes, said coating comprising atleast one oxide of an alkaline earth metal and a quantity of zirconium dioxide in a critical amount between zero percent and eleven percent of the total weight of -all the oxides, and corresponding to an amount therebetween giving substantially maximum cathode life within sad range.
  • a iluorescent lamp comprising a sealed light-transmitting envelope, a coating of iluorescent material on the inner wall of said envelope, a quantity of mercury in said envelope, a filling of inert gas in said envelope, illamentary electrodes in said envelope, and a coating on said electrodes, said coating consisting essentially of oxides and including at least one oxide of an alkaline earth metal and a quantity of zirconium dioxide in a critical amount, between zero percent and eleven percent of the total weight of all the oxides, and corresponding to an amount therebetween giving substantially maximum cathode life within said range.
  • a uorescent lamp comprising a sealed light-transmitting envelope, a coating of iluorescent material on the inner wall of said envelope, a quantity of mercury in said envelope, a filling of inert gas in said envelope, a iliamentary electrode of coiled tungsten wire at each end of said envelope, and an electron-emissive material carried by said electrode and consisting essentially of oxides and including at least one oxide of an alkaline earth metal and a quantity of zirconium dioxide in a critical amount, between zero percent and eleven percent of the total weight of all the oxides, and corresponding to an amount therebetween giving substantially maximum cathode life within said range.
  • a iluorescent lamp comprising a sealed elongated light-transmitting tubular envelope, a coating of iluorescent material on the inner wall of said envelope, a quantity of mercury in said envelope, a filling of inert gas at low pressure within said envelope, a iilamentary electrode at each end of said envelope and wound into a minor coil with the latter wound into a major coil to form a. coiled-coil, and aneleetron-emissive oosting material filling the space within said minor coil only and" comprising at least-one oxide of an alkaline-earth metal and a. quantity of zireonium dioxide. in a critical amount between zero and eleven percent of the total weight of all the oxides and corresponding to an amount therebetween giving substantially maximum cathode life within said range.

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  • Discharge Lamp (AREA)
US752698A 1947-06-05 1947-06-05 Electrode coating for discharge devices Expired - Lifetime US2530394A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE482916D BE482916A (en(2012)) 1947-06-05
US752698A US2530394A (en) 1947-06-05 1947-06-05 Electrode coating for discharge devices
FR966907D FR966907A (fr) 1947-06-05 1948-05-28 Perfectionnements au revêtement d'électrodes pour dispositifs à décharge
GB15207/48A GB655123A (en) 1947-06-05 1948-06-04 Electrode coating for discharge devices
DES20260A DE974434C (de) 1947-06-05 1950-10-03 Elektrische Niederdruck-Entladungslampe

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US752698A US2530394A (en) 1947-06-05 1947-06-05 Electrode coating for discharge devices

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US2530394A true US2530394A (en) 1950-11-21

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US752698A Expired - Lifetime US2530394A (en) 1947-06-05 1947-06-05 Electrode coating for discharge devices

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US (1) US2530394A (en(2012))
BE (1) BE482916A (en(2012))
DE (1) DE974434C (en(2012))
FR (1) FR966907A (en(2012))
GB (1) GB655123A (en(2012))

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2724070A (en) * 1953-02-09 1955-11-15 Westinghouse Electric Corp Cathode coating for electrical discharge devices and method for making the same
DE1011073B (de) * 1952-11-22 1957-06-27 Westinghouse Electric Corp Elektronenemittierender UEberzug fuer Elektroden von elektrischen Gasentladungsgefaessen
US2806970A (en) * 1954-03-01 1957-09-17 Westinghouse Electric Corp Electron emission coatings and method of preparing air stabilized barium oxide
DE966927C (de) * 1951-09-23 1957-09-19 Quarzlampen Gmbh Elektrische Hochdruckentladungslampe
US2831137A (en) * 1955-02-23 1958-04-15 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Cathode coating
US2935637A (en) * 1957-03-05 1960-05-03 Thomas M Cortese Fluorescent lamp
US3069580A (en) * 1953-10-28 1962-12-18 Sylvania Electric Prod Fluorescent lamp
US5471110A (en) * 1991-12-23 1995-11-28 Philips Electronics North America Corporation High pressure discharge lamp having filament electrodes
CN1068708C (zh) * 1992-12-02 2001-07-18 松下电工株式会社 荧光灯用电极
US20060214591A1 (en) * 2003-07-29 2006-09-28 Koninklijke Philips Electronics N.V. Low-pressure mercury vapor discharge lamp having determined probability of failure

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE518639A (en(2012)) * 1952-03-24
NL95838C (en(2012)) * 1952-04-24
NL193963C (nl) * 1994-05-04 2001-03-02 Matsushita Electric Works Ltd Elektrode voor toepassing in een fluorescerende lamp en werkwijze ter vervaardiging daarvan.

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US1821359A (en) * 1928-04-13 1931-09-01 Rca Corp Wehnelt-cathode
US1823984A (en) * 1926-05-13 1931-09-22 Communications Patents Inc Cathode for thermionic devices
US1903144A (en) * 1928-06-19 1933-03-28 Electrons Inc Rectifying tube
US2238595A (en) * 1938-09-29 1941-04-15 Westinghouse Electric & Mfg Co Oxide coated cathode
US2249672A (en) * 1936-12-10 1941-07-15 Gen Electric Discharge device

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DE597580C (de) * 1928-05-01 1934-05-26 Osram G M B H Komm Ges Elektrische Leucht- oder Ultraviolett-Bestrahlungsroehre
US1925648A (en) * 1928-09-21 1933-09-05 Hans J Spanner Lighting device
DE627617C (de) * 1928-09-21 1936-03-19 Osram G M B H Zuendvorrichtung fuer elektrische Gasentladungslampen mit langgestrecktem Entladungsweg
US1883898A (en) * 1928-12-14 1932-10-25 Westinghouse Electric & Mfg Co Thermionic cathode
US2097261A (en) * 1929-04-30 1937-10-26 Spanner Hans Joachim Lighting device
DE627520C (de) * 1929-05-05 1936-03-17 Osram G M B H Komm Ges Elektrische Entladungsroehre beliebiger Fuellung mit Gluehelektroden und Entladung durch die positive Saeule
FR694941A (fr) * 1929-07-02 1930-12-09 Tubes à décharge, en particulier tubes luminescents et irradiants
DE624620C (de) * 1929-08-19 1936-01-24 Linde Eismasch Ag Verfahren zur Ausscheidung von Daempfen aus Gasen
NL35601C (en(2012)) * 1930-06-16
DE581872C (de) * 1930-06-17 1933-08-04 Osram G M B H Komm Ges Elektrische Entladungsroehre
DE696506C (de) * 1930-12-07 1940-09-23 Osram G M B H Komm Ges Elektrische Hochdruckentladungsroehre fuer Beleuchnd Zusatz eines verdampfbaren Metalls
DE606407C (de) * 1932-12-06 1934-12-01 Patra Patent Treuhand Gluehkathode fuer elektrische Leuchtroehren, die zwei uebereinanderliegende Lagen verschiedener Erdalkalimetalloxyde aufweist
BE481787A (en(2012)) * 1940-11-23

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1823984A (en) * 1926-05-13 1931-09-22 Communications Patents Inc Cathode for thermionic devices
US1821359A (en) * 1928-04-13 1931-09-01 Rca Corp Wehnelt-cathode
US1903144A (en) * 1928-06-19 1933-03-28 Electrons Inc Rectifying tube
US2249672A (en) * 1936-12-10 1941-07-15 Gen Electric Discharge device
US2238595A (en) * 1938-09-29 1941-04-15 Westinghouse Electric & Mfg Co Oxide coated cathode

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE966927C (de) * 1951-09-23 1957-09-19 Quarzlampen Gmbh Elektrische Hochdruckentladungslampe
DE1011073B (de) * 1952-11-22 1957-06-27 Westinghouse Electric Corp Elektronenemittierender UEberzug fuer Elektroden von elektrischen Gasentladungsgefaessen
US2724070A (en) * 1953-02-09 1955-11-15 Westinghouse Electric Corp Cathode coating for electrical discharge devices and method for making the same
DE967713C (de) * 1953-02-09 1957-12-05 Westinghouse Electric Corp Emissionselektrode fuer elektrische Entladungsroehren und Verfahren zur Herstellung dieser Elektrode
US3069580A (en) * 1953-10-28 1962-12-18 Sylvania Electric Prod Fluorescent lamp
US2806970A (en) * 1954-03-01 1957-09-17 Westinghouse Electric Corp Electron emission coatings and method of preparing air stabilized barium oxide
US2831137A (en) * 1955-02-23 1958-04-15 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Cathode coating
US2935637A (en) * 1957-03-05 1960-05-03 Thomas M Cortese Fluorescent lamp
US5471110A (en) * 1991-12-23 1995-11-28 Philips Electronics North America Corporation High pressure discharge lamp having filament electrodes
CN1068708C (zh) * 1992-12-02 2001-07-18 松下电工株式会社 荧光灯用电极
US20060214591A1 (en) * 2003-07-29 2006-09-28 Koninklijke Philips Electronics N.V. Low-pressure mercury vapor discharge lamp having determined probability of failure
US7358677B2 (en) * 2003-07-29 2008-04-15 Koninklijke Philips Electronics, N.V. Low-pressure mercury vapor discharge lamp having determined probability of failure

Also Published As

Publication number Publication date
GB655123A (en) 1951-07-11
DE974434C (de) 1960-12-22
BE482916A (en(2012))
FR966907A (fr) 1950-10-20

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