US3914636A - Discharge lamp - Google Patents

Discharge lamp Download PDF

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Publication number
US3914636A
US3914636A US466647A US46664774A US3914636A US 3914636 A US3914636 A US 3914636A US 466647 A US466647 A US 466647A US 46664774 A US46664774 A US 46664774A US 3914636 A US3914636 A US 3914636A
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United States
Prior art keywords
discharge lamp
thorium
rare earth
earth metal
silicon
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Expired - Lifetime
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US466647A
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English (en)
Inventor
Minoru Sugiura
Kyou-Ichi Maseki
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Iwasaki Denki KK
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Iwasaki Denki KK
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Publication date
Application filed by Iwasaki Denki KK filed Critical Iwasaki Denki KK
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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
    • H01J61/073—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

  • the present invention relates to a so-called additive type mercury discharge lamp, wherein, in addition to mercury and a rare gas, at least one kind of a suitable luminous metal and a halogen in elemental form or in the form of a metal halide are filled and sealed in the transparent arc tube positioned in the-discharge lamp.
  • the additive-type mercury discharge lamp is superior to the usual high pressure mercury vapor discharge lamp in its luminous efficiency and colour rendering and has become an important lighting source for general illumination purposes.
  • Such an additive-type mercury discharge lamp wherein sodium, scandium, thorium and a halogen in elemental form or in the form of a metal halide are filled and sealed in an arc tube together with mercury and a rare gas is well known in the art.
  • This lamp has the advantage that an excellent colour rendering can be obtained owing to the luminescence of the scandium filled in the arc tube, but requires a relatively high starting voltage.
  • thorium oxide For reducing the starting voltage, it has been proposed to apply thorium oxide to each electrode, as an electron emissive material. Such application of thorium oxide, however, lowers the lumen maintenance factor of the lamp. Further, such discharge lamp has serious disadvantages in that a partial transparency loss of the arc tube and a deformation or loss of the tip end of each electrode gradually occur due to the metallic scandium filled in the arc tube and the thorium oxide applied to the electrodes as the electron emissive material.
  • Such a discharge lamp not only has a high lumen maintenance factor but also exhibits substantially no partial transparency loss of the arc tube or deformation or wear of the electrode tip ends. Further, a luminous spectrum analysis of the present discharge lamp shows the presence of scandium, despite the fact that scandium is not sealed therein in its elementary state. This result is due to the fact that the scandium oxide applied to the electrodes reacts with the thorium halide formed during operation of the lamp to form scandium halide, as shown in the following equation, which halide contributes to the total luminescence of the lamp:
  • X represents a halogen atom, for instance, iodine.
  • Scandium oxide as the substance applied to the electrodes may be substituted by one or more rare earth metal oxides.
  • a mixture of scandium oxide and at least one other rare earth metal oxide can also be used for this purpose.
  • Metallic thorium filled in the sealed arc tube may be:
  • a principal object ofthe present invention is to provide an additive type mercury discharge lamp which obviates and overcomes the disadvantages of the conventional one referred to above.
  • a specific object of the present invention is to provide an additive type mercury discharge lamp, which can be operated with a relatively low starting voltage and shows a relatively high lumen maintenance factor, a less partial transparency loss of the arc tube and a less deformation or wear of the electrode tip ends in comparison with any conventional discharge lamp of this type.
  • the objects referred to and the other various objects to be appreciated by studying the specification can be attained by an additive type mercury discharge lamp, wherein the electrodes for the lamp are coated with at least one rare earth metal oxide and a substance that reacts with said oxide, during operation of the lamp, to form a halide of the rare earth metal is filled in the arc tube.
  • FIG. 1 is a longitudinal cross section of an-additi ve type mercury discharge lamp according to the present invention.
  • FIG. 2 is a graph showing thelife performance curves of the discharge lamp according to the present invention and of a conventional one of this type.
  • an additive type mercury discharge lamp is generally designated by reference numeral 10.
  • the arc tube 10 includes a radiation transmitting sealed tubular body 12 of a transparent heat-resisting material, such as quartz glass, a pair of electrodes 14, 16 arranged oppositely at both ends of said tubular body lead-out wires 18, 20, connectors 22, 24 for connecting the electrodes l4, 16 to the lead-out wires 18. 20, respectively and being made of a metallic foil, for instance, molybdenum foil, and lagging members 26, 28 mounted on the end parts of the body so as to surround same near the electrodes l4, 16 from the outside of the tubular body 12.
  • Both ends of the body 12 are pinch-sealed, so that an outer end of each electrode connects electrically to an inner end of each lead-out wire through the respective connector.
  • the structure per se of the discharge lamp is well known in the art, but electric power and dimensions and volume of a typical one are shown as follows: Power: 400 W Dimensions of the Arc Tube: Inner diameter: about 20 mm Distance between electrodes: about 45 mm Inner volume: 16 cc EXAMPLE 1 In such an arc tube as shown in FIG.
  • a conventional discharge lamp was manufactured, by applying thorium oxide to the electrodes and by using an arc tube similar to that illustrated in FIG. 1 and sealing in the arc tube 7mg of mercury iodide, 20mg of sodium iodide, 0.5mg of scandium, 1mg of thorium and argon gas (sealing pressure: 20 mmI-Ig), and then tested to obtain the following results:
  • FIG.. 2 shows curves of the life performances of the discharge lamp according to the present invention and the conventional discharge lamp referred to hereinabove as control".
  • Life performance curve A of the discharge lamp according to the present invention shows no sudden reduction in total luminous flux during operation, but curve B of the conventional discharge lamp shows a sudden reduction in total luminous flux at the initial stage of its operation.
  • EXAMPLE 2 In a tubular body as shown in FIG. 1 and having dimensions as referred to, mg of mercury iodide, 2mg of thallium iodide, 2mg of throium and argon gas (billing pressure: mmHg) were sealed, after having applied dysprosium oxide to each electrode.
  • An additive type mercury discharge lamp (400 W) which comprises the resulting arc tube was tested by lighting the same to obtain the following results:
  • EXAMPLE 3 Various additive type mercury discharge lamps were manufactured as in theprecedingExamples, excepting that, as the substance applied to each electrode, a rare earth metal oxide other than scandium and dysprosium oxides, such as an an oxide of yttrium, holmium, thulium, or erbium, or a mixture of rare earth metal oxides was used for each lamp and excepting that, as the substance reacting with such oxideor oxides, thoriumaluminum, thorium-silicon, throium-aluminum-silicon, aluminum, silicon and aluminum-silicon were used for each lamp. The lamps were tested to obtain results similar to those obtained in Examples 1 and 2.
  • a rare earth metal oxide other than scandium and dysprosium oxides such as an oxide of yttrium, holmium, thulium, or erbium, or a mixture of rare earth metal oxides was used for each lamp and excepting that, as the substance reacting with such oxideor oxides,
  • An additive-type mercury discharge lamp which includes an arc tube comprising a radiationtransmitting sealed tubular body, a pair of electrodes respectively arranged at the opposite ends of said body, a lead-out conductor connected electrically to each electrode, and a discharge-sustaining filling of preselected materials in predetermined amounts enclosed in said body and including mercury, a rare gas, and at least one halogen in elemental form or in the form of a metal halide, at least one of said electrodes being coated with at least one rare earth metal oxide, and said filling also including a substance that reacts with said rare earth metal oxide, during operation of the lamp, to form a halide of said rare earth metal.
US466647A 1973-05-10 1974-05-03 Discharge lamp Expired - Lifetime US3914636A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5117373A JPS5416671B2 (de) 1973-05-10 1973-05-10

Publications (1)

Publication Number Publication Date
US3914636A true US3914636A (en) 1975-10-21

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Family Applications (1)

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US466647A Expired - Lifetime US3914636A (en) 1973-05-10 1974-05-03 Discharge lamp

Country Status (5)

Country Link
US (1) US3914636A (de)
JP (1) JPS5416671B2 (de)
DE (1) DE2422576C3 (de)
GB (1) GB1462955A (de)
NL (1) NL182602C (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2485260A1 (fr) * 1980-06-20 1981-12-24 Gen Electric Lampe a decharge a halogenures metalliques perfectionnee
US5691601A (en) * 1993-08-16 1997-11-25 Patent-Treuhand-Gesellschaft F. Elektrische Gluehlampen Mbh Metal-halide discharge lamp for photooptical purposes
EP0834904A2 (de) * 1996-10-07 1998-04-08 Ushiodenki Kabushiki Kaisha Hochdruck Quecksilber-Ultravioletlampe
WO2007026288A2 (en) * 2005-09-02 2007-03-08 Philips Intellectual Property & Standards Gmbh High-pressure gas discharge lamp
CN102484038A (zh) * 2009-09-10 2012-05-30 皇家飞利浦电子股份有限公司 高强度放电灯

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51107682A (ja) * 1975-03-19 1976-09-24 Iwasaki Electric Co Ltd Kinzokujokihodento
JPS5416869A (en) * 1976-10-26 1979-02-07 Japan Storage Battery Co Ltd Metallic vapor discharge lamp
JPS5367972A (en) * 1976-11-30 1978-06-16 Mitsubishi Electric Corp Electrode for elctric discharge lamp
JPS53128172A (en) * 1977-04-14 1978-11-08 Toshiba Corp Metal vapor discharge lamp
JPS5710654Y2 (de) * 1979-10-22 1982-03-02

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3530327A (en) * 1968-03-11 1970-09-22 Westinghouse Electric Corp Metal halide discharge lamps with rare-earth metal oxide used as electrode emission material

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3530327A (en) * 1968-03-11 1970-09-22 Westinghouse Electric Corp Metal halide discharge lamps with rare-earth metal oxide used as electrode emission material

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2485260A1 (fr) * 1980-06-20 1981-12-24 Gen Electric Lampe a decharge a halogenures metalliques perfectionnee
US5691601A (en) * 1993-08-16 1997-11-25 Patent-Treuhand-Gesellschaft F. Elektrische Gluehlampen Mbh Metal-halide discharge lamp for photooptical purposes
EP0834904A2 (de) * 1996-10-07 1998-04-08 Ushiodenki Kabushiki Kaisha Hochdruck Quecksilber-Ultravioletlampe
EP0834904A3 (de) * 1996-10-07 1998-06-03 Ushiodenki Kabushiki Kaisha Hochdruck Quecksilber-Ultravioletlampe
WO2007026288A2 (en) * 2005-09-02 2007-03-08 Philips Intellectual Property & Standards Gmbh High-pressure gas discharge lamp
WO2007026288A3 (en) * 2005-09-02 2007-12-06 Philips Intellectual Property High-pressure gas discharge lamp
CN102484038A (zh) * 2009-09-10 2012-05-30 皇家飞利浦电子股份有限公司 高强度放电灯
CN102484038B (zh) * 2009-09-10 2015-09-23 皇家飞利浦电子股份有限公司 高强度放电灯

Also Published As

Publication number Publication date
NL182602C (nl) 1988-04-05
JPS501573A (de) 1975-01-09
NL7406360A (de) 1974-11-12
JPS5416671B2 (de) 1979-06-23
DE2422576A1 (de) 1974-11-21
GB1462955A (en) 1977-01-26
DE2422576B2 (de) 1979-03-22
DE2422576C3 (de) 1979-11-15
NL182602B (nl) 1987-11-02

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