US3781586A - Long lifetime mercury-metal halide discharge lamps - Google Patents

Long lifetime mercury-metal halide discharge lamps Download PDF

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Publication number
US3781586A
US3781586A US00311943A US3781586DA US3781586A US 3781586 A US3781586 A US 3781586A US 00311943 A US00311943 A US 00311943A US 3781586D A US3781586D A US 3781586DA US 3781586 A US3781586 A US 3781586A
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lamp
sodium
present
iodide
envelope
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Expired - Lifetime
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US00311943A
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English (en)
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P Johnson
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General Electric Co
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General Electric Co
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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
    • H01J61/12—Selection of substances for gas fillings; Specified operating pressure or temperature
    • H01J61/18—Selection of substances for gas fillings; Specified operating pressure or temperature having a metallic vapour as the principal constituent
    • H01J61/22—Selection of substances for gas fillings; Specified operating pressure or temperature having a metallic vapour as the principal constituent vapour of an alkali metal

Definitions

  • the present invention relates to mercury-metallic halide vapor-arc discharge lamps of the type containing mercury and one or more vaporizable metallic halides which are dissociated in the heat of an are between a pair of primary arc electrodes extending into an evacuable envelope wherein the sodium atom is a principal radiating specie. More particularly, this invention relates to such vapor arc. discharge lamps wherein the presence of free iodinedue to chemical and related other mechanisms of clean-up of sodium from the discharge envelope is prevented and the life of the lamp is greatly extended.
  • the emission of a vapor-arc lamp is obtained from the line broadened spectra of one or more metals included within the lamp envelope as the halide thereof, preferably the iodide.
  • sodium iodide is disclosed as the source of one principal radiating specie.
  • the sodium atom as a principal radiating specie is particularly attractive sinee'the excitation potential of the sodium atom is one of the lowest of the materials which have been found to be suitable for additives in halide forms, principally as the iodide.
  • the sodium atom emits an orange ed radiation which is substantially the line broadened characteristic of the sodium D lines
  • the addition of additional iodides as, for example, the iodides of thallium and indium, which emit in the green and blue portions of the visible spectrum, produces a, total emission wherein, the green and blue emissions blend with the emission of the so- 7 dium atom to produce a pleasing white, or near-white spectral rendition.
  • lamps of the type described utilizing sodium as a principal radiating specie are greatly advantageous, the chemical, activity of sodium and. other related effects cause the amount, of sodium within the discharge envelope progressively to. decrease with increasing time of lamp operation; Decreasing sodium content causes an increase in the voltage drop between the arc electrodes and a gradual change, of the spectral. emissivity in. the direction of the blue together with a decrease in efficacy, and constriction and instabilities of the vapor arc.
  • a. principal object of the present; invention is to, provide metallic vaporarc lamps in which sodium is a principal radiating specie having greatly in.- creased lifetimes.
  • Yet another object of the present invention is to provide lamps of the, type described, wherein long useful lifetime is achieved without .loss of efficacy or color rendition.
  • Another object of the present invention is to provide lamps of the typedescribed wherein-sodium is. a principal emitting specie in which the presence of free iodine; is prevented or minimized.
  • I provide a mercury-metallichalid'e vapor are discharge lamp having an evacuable envelope containing a pair of arc electrodes and a vaporizable charge ineluding a quantity of mercury, a quantity of sodium io dide, with or without other iodides, whose spectral emissivity blends with the emissivity of the sodium atom to provide white or near-white spectral rendition and a quantity of elemental thin sufficient to getter any free iodine which would be present within the lamp due to the clean-up of sodium from the sodium iodide charge, thus greatly extending the useful lifetime of the lamp without loss of spectral fidelity or substantial increase in voltage drop between the arc electrodes thereof.
  • a mercury-metallic halide vapor-arc discharge lamp constructed in accord with the present invention includes an exterior evacuable transmissive envelope I mounted upon a screw-type contact-making base 2 and including therein an inner arc containing envelope 3.
  • Inner envelope 3 is lighttransmissive, generally cylindrical in shape, hermetically sealed and is terminated at either end with pinched-off sections 4 and 5 which hermetically seal the interior thereof and through which thermionic arc electrodes 6 and 7 are suspended by means of in leads 8 and 9, respectively.
  • Envelope l may be any suitable high temperature, hard, light-transmissive glass as, for example, Pyrex or ⁇ (ycor.
  • Envelope 3 may be any similar lighttransmissive, but higher temperature resistant material such as fused quartz, Lucalox, (U.S. Pat. No. 3,026,210) or high-density yttria, (Yttralox U.S. Pat. No. 3,545,987), or other similar high denisty, light-transmissive, or light-transparent ceramics. Since,
  • the coolest portion of theinner wall of discharge envelope 3 is approximately at least 5009C, and preferably at least 600C, the hotter portions thereof immediately adjacentthe arc, generally are of the order of 1,000C, at least, and may be higher. Accordingly, envelope 3 should be of such materials as set forth hereinbefore as to withstand such temperatures without losing mechanical strength or suffering loss of transmissivity.
  • Arc electrodes 6 and 7 are spaced a predetermined distance apart depending upon the power rating of the lamp so as to sustain a high current electric are therebetween for the vaporization of the vaporizable constituents contained therein and the production of a highintensity radiation of appropriate wavelengths.
  • a startingelectrode 10 is located within one end of inner envelope. 3i and is sealed through pinched region 5 of inner envelope thereof. Starting electrode 10 is connectedthrough a voltage dropping resistance 11 to a lead and support member 12 which is at the same electrical potential with another lead and support member l3',,both of which are connected to one contact member of connecting base 2. It will be appreciated, however, that other means than starting electrode 10 may be utilized to start the lamp.
  • outer envelope l contains a starting gas as, for example, one of the noble gases such as argon, generally at a pressure of approximately 5 to 50 torr and preferably of approximately torr. This gas is utilized in starting the lamp by serving as the conducting specie of an initial are which vaporizes the main arc specie.
  • a starting gas as, for example, one of the noble gases such as argon, generally at a pressure of approximately 5 to 50 torr and preferably of approximately torr. This gas is utilized in starting the lamp by serving as the conducting specie of an initial are which vaporizes the main arc specie.
  • Discharge envelope 3 also contains a charge 19 which containsthe vaporizable materials from which the light emitting specie are derived.
  • Charge 19 is generally in the form of a globule containing mercury and one or more iodides, including sodium iodide, which are the iodides of the radiating metallic specie specifically chosen to produce the spectral emissivity desired from the lamp. For general purposes, it is desirable that white light be obtained and one such charge ideally suited to produce white light constitutes the iodides of sodium, thallium, and indium.
  • Charge 19 also contains, in accord with the invention, a quantity of elemental tin. The quantity of mercury, the various iodides, and tin within charge 19 vary with the power rating of the lamp.
  • a 400 watt lamp may have a discharge envelope of approximately 20 cc, while for a 1,000 watt lamp the volume thereof. is approximately 35 cc, generally.
  • the vapor pressure of the respective materials within the discharge envelope during operation of the lamp is usually within the same range.
  • mercury is present within the range of l to 20 atmospheres partial pressure.
  • a sufficient quantity of mercury is therefore provided in the charge which, at lamp operating temperatures, (wherein the minimum interior bulb wall temperature is maintained at a value of at least 500C, and preferably at least 600C) is sufficient to provide a quantity of mercury vapor to establish such a pressure, leaving a residual amount of mercury in the charge with the unvaporized halides and tin.
  • Sufficient sodium halide and any other halides utilized is added in order to produce a saturated vapor pressure of these materials at lamp operating temperatures.
  • Such vapor pressure is generally of the order of 0.05 to 25 torr for sodium iodide, 0.1 lOO torr for indium iodide, and 0.1 to torr for thallium iodide.
  • free tin added to charge 19 is vaporized along with the iodides and mercury of charge 19 and, although the tin radiation is not significant as comapred with the sodium radiation, the elemental tin serves to maintain a thermodynamic equilibrium with the iodine freed by sodium clean-up so that, in the discharge envelope within and surrounding the metallic vapor arc, tin iodide, rather than free iodine, is present and constriction of the are, together with all of .the attendant disadvantages thereof, is avoided.
  • Lamps constructed in accord with the present invention show a remarkable improvement over similar lamps which do not contain elemental tin in the charge from which the light emitting specie is eventually evolved.
  • a standard prior art 400 watt mercury-metallic iodide vapor arc lamp using sodium iodide, thallium iodide, and indium iodide, typically has a maximum useful normal lifetime of approximately 8,000 hours and may under normal performance specifications have a lifetime of as short as 4,000 hours. Lamps of the same rating constructed in accord with the present invention, on the other hand, routinely have lifetimes of 20,000 hours or greater.
  • the saturation pressure of sodium which is approximately 0.05 to 25 torr, depending upon the operating temperature of the lamp, may be maintained within the discharge envelope and a sufficient quantity of sodium iodide may be added to the charge in order to continue the saturation pressure until the 20,000 hour lifetime of the lamp, due to the expiration of other components thereof, has arrived.
  • the amount of tin which'must he added to the charge is that which is sufficient over the operating lifetime of the lamp to prevent the existence within the discharge envelope of any free iodine.
  • a maximum of one-half mole of free tin should be added for each mole of sodium iodide present initially in charge 19.
  • the amount of sodium iodide added to lamps in accord with the present invention generally range from approximately 2 to 6 milligrams thereof per cubic centimet er of discharge tube volume.
  • sodium iodide is present in the charge in a range of approximately 40 to 120 milligrams.
  • the amount of mercury is generally chosen so as to be sufficient upon near total vaporization thereof to form a partial pressure of mercury in the discharge envelope of approximately 1 to 20 atmospheres.
  • the amount of other halides added in lamps of this type as, for example, thallium iodide and indium iodide, are not involved in the free iodine and the sodium clean up mechanism, the amount of such other halides, specifically the iodides, may be added as is conventional in mercurymetallic iodide lamps in order to achieve the desired emission, generally white or near-white.
  • the amount of thallium iodide and indium iodide in such lamps may be such as to establish'a partial pressure thereof under lamp operating conditions of approximately 0.1 to torr each within the envelope.
  • the amount of tin added is chosen to be adequate to compensate for the amount of sodium cleaned up, not the total amount of sodium present.
  • a larger molar fraction of tin is added than when a large quantity of sodium is added for spectral fidelity purposes.
  • the ultimate criterion is to provide sufficient tin to preclude the presence of free iodine within the discharge envelope during useful lamp life.
  • Such a charge of the typical 400 watt mercury-metallic halide lamp may be completed by adding from 0.5 to 5.0 milligrams of thallium iodide and 0.5 to 5.0 milligrams of indium iodide.
  • One such lamp utilized the following specific charge 80 mgs sodium iodide 80 mgs mercury 20 mgs tin 2 mgs thallium iodide 1 mg indium iodide 20 torr argon This lamp had an initial interelectrode voltage drop of 135 volts and, after 20,000 hours of operation, still had a relatively low interelectrode drop of 150 volts and emitted substantially white light with only barely observable constriction of the are.
  • a line voltage of 220 or 440 volts isapplied to a conventional mercury-metallic halide ballast transformer, such as a General Electric Ballast Cat. No. 9SA20H1 l, 22 and applied by means of leads 23 and 24 to the base of the lamp and thence to the respective arc electrodes 6 and 7 and to starter electrode 10.
  • An initial arc is striken between starter electrode 10 and main electrode 7, and is sufficient to cause the ionization of the low pressure inert gas within the envelope, thus facilitating a breakdown between main electrodes 6 and 7.
  • Such an initial breakdown in the inert gas heats the mercury of the charge so that a sufficient amount of mercury is vaporized to cause a mercury discharge to be established between arc electrodes 6 and 7.
  • the resistance 16 in the circuit to starter electrode is sufficient to extinguish the auxiliary are between starter electrode and main electrode 7.
  • the mercury are established between the main electrodes 6 and 7 generates a sufficient quantity of heat to vaporize the respective halides, as, for example, the iodides of thallium, sodium, and indium, and elemental tin to cause the sodium, thallium, and indium to be dissociated and cause the establish-ment of a sodium, thallium, and indium arc discharge, for example.
  • any iodine which tends to be released in the discharge envelope by virtue of clean-up of sodium is immediately combined with the tin vapor to form tin iodide which precludes the constriction of the arc discharge and attendant instabilities thereof, as well as preventing substantial increase of the interelectrode voltage drop and adverse heating of the discharge envelope, while at the same time maintaining color fidelity throughout the normal lifetime of the lamp as determined by the lifetime of other lamp constituents as, for example, the cathode.
  • Lamps constructed in accord with the present invention exhibit lifetimes of at least 20,000 hours, as compared with the 4,000 to 8,000 hours normally achievable with mercury-metallic vapor arc discharge lamps of the prior art.
  • a high pressure metal vapor electric discharge lamp comprising:
  • d. means connected to said arc-electrodes for applying thereto a voltage having current capacity sufficient to establish an electric discharge within said lamp envelope which maintains the coolest portion of the inner wall thereof at a temperature of at least 500C to provide sufficient vaporization of said fill to provide high efficacy substantially white visible radiation.
  • said charge contains at least one additional vaporizable dissociable halide of 10.
  • said discharge envelope also contains. quantities of thallium iodide and indium iodide sufficient to cause the spectral emission a light emitting metal which combines with the emis- 5 from Said p to be essentially White lightsion of sodium to provide a desired spectral rendition.

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US00311943A 1972-12-04 1972-12-04 Long lifetime mercury-metal halide discharge lamps Expired - Lifetime US3781586A (en)

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US31194372A 1972-12-04 1972-12-04

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US (1) US3781586A (it)
JP (1) JPS4988377A (it)
BE (1) BE808033A (it)
DE (1) DE2359138A1 (it)
NL (1) NL7315893A (it)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3958145A (en) * 1973-03-06 1976-05-18 U.S. Philips Corporation High pressure, mercury vapor, metal halide discharge lamp
US4135110A (en) * 1975-02-13 1979-01-16 Thorn Electrical Industries Limited Electrical discharge lamp
US4171498A (en) * 1976-12-06 1979-10-16 Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh High pressure electric discharge lamp containing metal halides
US4197480A (en) * 1978-09-11 1980-04-08 Westinghouse Electric Corp. Reflector-type hid sodium vapor lamp unit with dichroic reflector
FR2469798A1 (fr) * 1979-11-13 1981-05-22 Gen Electric Lampe a decharge d'arc a halogenures metalliques comportant un getter pour l'iode
US4298813A (en) * 1978-10-23 1981-11-03 General Electric Company High intensity discharge lamps with uniform color
EP0057093A1 (en) * 1981-01-23 1982-08-04 North American Philips Lighting Corporation High intensity discharge lamps
US4581557A (en) * 1979-01-02 1986-04-08 General Electric Company Stabilized high intensity discharge lamp
US4717852A (en) * 1982-08-30 1988-01-05 Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh Low-power, high-pressure discharge lamp
US4929869A (en) * 1987-11-12 1990-05-29 Kabushiki Kaisha Toshiba High intensity discharge lamp containing iron and silver in the arc tube filling
EP0543624A1 (en) * 1991-11-21 1993-05-26 General Electric Company Metal halide discharge lamp
US5229686A (en) * 1991-10-09 1993-07-20 Gte Products Corporation Mercury vapor discharge lamp containing means for reducing mercury leaching
US5434473A (en) * 1993-03-09 1995-07-18 Tungsram Co., Ltd. High pressure sodium vapor discharge lamp
US5438244A (en) * 1994-09-02 1995-08-01 General Electric Company Use of silver and nickel silicide to control iodine level in electrodeless high intensity discharge lamps
US6107742A (en) * 1997-04-03 2000-08-22 Matsushita Electronics Corporation Metal halide lamp
US6362571B1 (en) * 1998-04-08 2002-03-26 U.S. Philips Corporation Metal-halide lamp with ionizable filling and oxygen dispenser to avoid blackening and extend lamp life
DE10101508A1 (de) * 2001-01-12 2002-08-01 Philips Corp Intellectual Pty Hochdruckentladungslampe
WO2010133987A1 (en) * 2009-05-18 2010-11-25 Koninklijke Philips Electronics, N.V. Design spaces for high wattage ceramic gas discharge metal halide lamp to minimize arc bending
US20140252945A1 (en) * 2011-10-20 2014-09-11 Osram Gmbh Mercury vapor short arc lamp for dc operation with circular process

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1541437A (en) * 1975-02-13 1979-02-28 Thorn Electrical Ind Ltd Electrical discharge lamp

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3958145A (en) * 1973-03-06 1976-05-18 U.S. Philips Corporation High pressure, mercury vapor, metal halide discharge lamp
US4135110A (en) * 1975-02-13 1979-01-16 Thorn Electrical Industries Limited Electrical discharge lamp
US4171498A (en) * 1976-12-06 1979-10-16 Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh High pressure electric discharge lamp containing metal halides
US4197480A (en) * 1978-09-11 1980-04-08 Westinghouse Electric Corp. Reflector-type hid sodium vapor lamp unit with dichroic reflector
US4298813A (en) * 1978-10-23 1981-11-03 General Electric Company High intensity discharge lamps with uniform color
US4581557A (en) * 1979-01-02 1986-04-08 General Electric Company Stabilized high intensity discharge lamp
FR2469798A1 (fr) * 1979-11-13 1981-05-22 Gen Electric Lampe a decharge d'arc a halogenures metalliques comportant un getter pour l'iode
EP0057093A1 (en) * 1981-01-23 1982-08-04 North American Philips Lighting Corporation High intensity discharge lamps
US4360758A (en) * 1981-01-23 1982-11-23 Westinghouse Electric Corp. High-intensity-discharge lamp of the mercury-metal halide type which efficiently illuminates objects with excellent color appearance
US4717852A (en) * 1982-08-30 1988-01-05 Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh Low-power, high-pressure discharge lamp
US4929869A (en) * 1987-11-12 1990-05-29 Kabushiki Kaisha Toshiba High intensity discharge lamp containing iron and silver in the arc tube filling
US5229686A (en) * 1991-10-09 1993-07-20 Gte Products Corporation Mercury vapor discharge lamp containing means for reducing mercury leaching
EP0543624A1 (en) * 1991-11-21 1993-05-26 General Electric Company Metal halide discharge lamp
US5434473A (en) * 1993-03-09 1995-07-18 Tungsram Co., Ltd. High pressure sodium vapor discharge lamp
US5438244A (en) * 1994-09-02 1995-08-01 General Electric Company Use of silver and nickel silicide to control iodine level in electrodeless high intensity discharge lamps
US6107742A (en) * 1997-04-03 2000-08-22 Matsushita Electronics Corporation Metal halide lamp
US6362571B1 (en) * 1998-04-08 2002-03-26 U.S. Philips Corporation Metal-halide lamp with ionizable filling and oxygen dispenser to avoid blackening and extend lamp life
DE10101508A1 (de) * 2001-01-12 2002-08-01 Philips Corp Intellectual Pty Hochdruckentladungslampe
WO2010133987A1 (en) * 2009-05-18 2010-11-25 Koninklijke Philips Electronics, N.V. Design spaces for high wattage ceramic gas discharge metal halide lamp to minimize arc bending
US20140252945A1 (en) * 2011-10-20 2014-09-11 Osram Gmbh Mercury vapor short arc lamp for dc operation with circular process

Also Published As

Publication number Publication date
BE808033A (fr) 1974-03-15
JPS4988377A (it) 1974-08-23
DE2359138A1 (de) 1974-06-12
NL7315893A (it) 1974-06-06

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