EP0136726A2 - Matériau émettant pour appareil de décharge à vapeur de sodium à haute intensité - Google Patents

Matériau émettant pour appareil de décharge à vapeur de sodium à haute intensité Download PDF

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Publication number
EP0136726A2
EP0136726A2 EP84111973A EP84111973A EP0136726A2 EP 0136726 A2 EP0136726 A2 EP 0136726A2 EP 84111973 A EP84111973 A EP 84111973A EP 84111973 A EP84111973 A EP 84111973A EP 0136726 A2 EP0136726 A2 EP 0136726A2
Authority
EP
European Patent Office
Prior art keywords
discharge device
oxide
pair
high intensity
electrodes
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.)
Withdrawn
Application number
EP84111973A
Other languages
German (de)
English (en)
Other versions
EP0136726A3 (fr
Inventor
Philip J. White
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.)
Osram Sylvania Inc
Original Assignee
GTE Products Corp
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 GTE Products Corp filed Critical GTE Products Corp
Publication of EP0136726A2 publication Critical patent/EP0136726A2/fr
Publication of EP0136726A3 publication Critical patent/EP0136726A3/fr
Withdrawn legal-status Critical Current

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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
    • H01J61/073—Main electrodes for high-pressure discharge lamps
    • H01J61/0735—Main electrodes for high-pressure discharge lamps characterised by the material of the electrode
    • H01J61/0737—Main electrodes for high-pressure discharge lamps characterised by the material of the electrode characterised by the electron emissive material

Definitions

  • This invention relates to high intensity sodium vapor discharge devices and more particularly to emissive materials for high intensity sodium vapor discharge devices.
  • High pressure sodium lamps having an elongated arc tube filled with large amounts of sodium and mercury and disposed within an evacuated glass envelope are well known in the art. Also well known is the fact that sodium loss has long been a problem in such lamps. Moreover, such undesirable features as increased voltage drop across the lamp and a reduction in the period of useful "life” have been traced to this undesired loss of sodium. Thus, it is a common practice to load or "saturate" high pressure sodium lamps with large amounts of sodium in order to compensate for the uncontrolled sodium losses during operational use of the discharge device.
  • An object of the present invention is to provide an enhanced high pressure sodium lamp. Another object of the invention is to improve the stability of a high pressure sodium lamp. Still another object of the invention is to reduce the sodium losses in a high pressure sodium lamp. A further object of the invention is to provide an improved unsaturated vapor high pressure sodium lamp.
  • a high pressure sodium lamp having an elongated ceramic tube filled with sodium and noble gases with leads extending therethrough and coupled to electrodes therein.
  • the leads are connected to electrical conductors within an envelope, and at least one of the electrodes within the arc tube includes therein or has an emissive material thereon which has a free energy of formation per mole of oxygen more negative than that of barium oxide (BaO).
  • BaO barium oxide
  • a high pressure sodium lamp includes an elongated outer glass envelope 3 attached to a normal screw-type base 5.
  • the lamp has a glass stem portion 7 hermetically sealed to the envelope 3, and a pair of electrical leads 9 and 11 are sealed into and pass through the glass stem portion 7 of the lamp.
  • An electrically conductive support member 13 is affixed to one of the electrical leads 9 and extends along the longitudinal axis of the envelope 3.
  • a pair of cross-members 15 and 17 are attached to opposite ends and extend normal to the longitudinal axis of the electrically conductive support member 13.
  • heat insulating sleeves 29 and 31 are wrapped about the opposite ends of the arc tube 19 in the vicinity of the electrodes 25 and 27.
  • the glass envelope 3 is evacuated and one or more getters 24, preferably barium, are positioned therein.
  • a lamp fill gas preferably sodium and mercury, is disposed within the arc tube 19.
  • This lamp fill gas may be of an amount sufficient to "saturate” or provide an excess amount of sodium therein, but preferably only sufficient fill gas is added to provide a lamp of the unsaturated vapor type.
  • the "saturated" lamp includes a gas phase saturated with sodium and mercury and a pool of excess sodium and mercury while the "unsaturated” does not include a pool of excess sodium and mercury.
  • a material having a free energy of formation more negative than about -180 K cal/mole at 1200° or more negative than barium oxide (BaO) is a preferred electrode emissive material.
  • thorium oxide (Th0 2 ) coatings are appropriate: scandium oxide (Sc 2 O 3 ): yttrium oxide (Y 2 O3); beryllium oxide (BeO); lanthanum oxide (La 2 O 3 ); cerium oxide (Ce 0 ) and hafnium oxide (HfO 2 ).
  • tungsten containing one or more of these emissive materials as inclusions in the tungsten, such as thoriated tungsten, is also an appropriate material for the electrodes 25 and 27.
  • test group (A) employed thorium oxide (ThO 2 ) as the emissive material and the control group (B) employed di-barium calcium tungstate as the emissive material.
  • ThO 2 thorium oxide
  • control group (B) employed di-barium calcium tungstate as the emissive material.
  • the test group (A) using Th0 2 as the emissive material, maintained a substantially constant level of sodium over an extended time period.
  • the control group (B) using di-barium calcium tungstate as an emissive material indicated an almost complete loss of sodium content within a relatively short operating time, about 400 minutes.
  • test results have indicated that high pressure sodium lamps, saturated and preferably unsaturated, are enhanced by the utilization of an emissive material having a free energy of formation per mole of oxygen more negative than that of barium oxide (BaO). Also, observation of unsaturated high pressure sodium lamps made with both di-barium calcium tungstate and with thorium oxide emissive materials indicates a very definite reduction in end blackening when thorium oxide is used as the emissive material. Both tests are indicative of the reduced loss of sodium within lamps employing an emissive material with a free energy of formation per mole of oxygen more negative than about -180 K cal/mole at about 1200° C.

Landscapes

  • Discharge Lamp (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
EP84111973A 1983-10-06 1984-10-05 Matériau émettant pour appareil de décharge à vapeur de sodium à haute intensité Withdrawn EP0136726A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US53960583A 1983-10-06 1983-10-06
US539605 1983-10-06

Publications (2)

Publication Number Publication Date
EP0136726A2 true EP0136726A2 (fr) 1985-04-10
EP0136726A3 EP0136726A3 (fr) 1986-01-22

Family

ID=24151917

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84111973A Withdrawn EP0136726A3 (fr) 1983-10-06 1984-10-05 Matériau émettant pour appareil de décharge à vapeur de sodium à haute intensité

Country Status (2)

Country Link
EP (1) EP0136726A3 (fr)
CA (1) CA1227521A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0647964A1 (fr) * 1993-10-07 1995-04-12 Koninklijke Philips Electronics N.V. Lampe à décharge à halogénure métallique haute pression
WO1998039791A3 (fr) * 1997-03-05 1999-03-04 Marcus Thielen Electrode froide pour decharges gazeuses
CN104183460A (zh) * 2013-05-28 2014-12-03 海洋王照明科技股份有限公司 陶瓷金卤灯电极及陶瓷金卤灯
CN104183456A (zh) * 2013-05-28 2014-12-03 海洋王照明科技股份有限公司 陶瓷金卤灯电极及陶瓷金卤灯

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL175771B (nl) * 1975-06-20 1984-07-16 Philips Nv Hogedrukgasontladingslamp en een werkwijze voor de vervaardiging hiervan.

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0647964A1 (fr) * 1993-10-07 1995-04-12 Koninklijke Philips Electronics N.V. Lampe à décharge à halogénure métallique haute pression
BE1007595A3 (nl) * 1993-10-07 1995-08-16 Philips Electronics Nv Hogedruk-metaalhalogenide-ontladingslamp.
US5530317A (en) * 1993-10-07 1996-06-25 U.S. Philips Corporation High-pressure metal halide discharge lamp with electrodes substantially free of thorium oxide
CN1069440C (zh) * 1993-10-07 2001-08-08 皇家菲利浦电子有限公司 高压金属卤化物放电灯
WO1998039791A3 (fr) * 1997-03-05 1999-03-04 Marcus Thielen Electrode froide pour decharges gazeuses
US6417607B1 (en) 1997-03-05 2002-07-09 Marcus Thielen Cold electrode for gas discharges
CN104183460A (zh) * 2013-05-28 2014-12-03 海洋王照明科技股份有限公司 陶瓷金卤灯电极及陶瓷金卤灯
CN104183456A (zh) * 2013-05-28 2014-12-03 海洋王照明科技股份有限公司 陶瓷金卤灯电极及陶瓷金卤灯

Also Published As

Publication number Publication date
EP0136726A3 (fr) 1986-01-22
CA1227521A (fr) 1987-09-29

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Legal Events

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19841005

AK Designated contracting states

Designated state(s): BE DE FR GB NL

PUAL Search report despatched

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AK Designated contracting states

Designated state(s): BE DE FR GB NL

17Q First examination report despatched

Effective date: 19871119

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19890503

RIN1 Information on inventor provided before grant (corrected)

Inventor name: WHITE, PHILIP J.