US3497742A - Short metal arc tube mounted within a ceramic reflector envelope - Google Patents

Short metal arc tube mounted within a ceramic reflector envelope Download PDF

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Publication number
US3497742A
US3497742A US691399A US3497742DA US3497742A US 3497742 A US3497742 A US 3497742A US 691399 A US691399 A US 691399A US 3497742D A US3497742D A US 3497742DA US 3497742 A US3497742 A US 3497742A
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United States
Prior art keywords
envelope
arc
lamp
metal vapor
tube
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Expired - Lifetime
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US691399A
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English (en)
Inventor
John F Richter
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Excelitas Technologies Illumination Inc
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Varian Associates Inc
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Assigned to ILC TECHNOLOGY, INC, A CORP. OF CALIF. reassignment ILC TECHNOLOGY, INC, A CORP. OF CALIF. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: VARIAN ASSOCIATED INC, A CORP. OF DEL.
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/98—Lamps with closely spaced electrodes heated to incandescence by light-emitting discharge, e.g. tungsten arc lamp
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/52—Cooling arrangements; Heating arrangements; Means for circulating gas or vapour within the discharge space

Definitions

  • a metal vapor arc lamp comprising a sealed arc tube confining an ionizable alkali metal, two spaced electrodes which penetrate the arc tube to define an arc gap there within, and means for heating the alkali metal to enable a voltage impressed across the arc gap to ionize the heated metal vapor and ignite the arc lamp.
  • the are tube is housed in a sealed envelope having a ceramic cylindrical section hermetically closed at each end by envelope membars which respectively comprise a reflector and an optical window.
  • This invention relates to metal vapor arc lamps and particularly to high intensity, short are metal vapor lamps having an integral reflector sealed within a ceramic envelope.
  • a high intensity short arc lamp is disclosed by applicant having a novel envelope comprising a ceramic cylinder hermetically closed at its ends by a reflector and an optical window. Housed within the envelope is an ionizable gas under pressure and two electrodes.
  • This structure provides a high intensity arc lamp having a composite, rugged, integral bulb and reflector devoid of glass-to-metal seals and consisting of material which will not react with the internal atmosphere.
  • the gaseous atmosphere may be an inert gas such as xenon, argon or krypton or a mixture consisting essentially of a metal vapor such as mercury, cesium, rubidium, sodium, potassium or lithium.
  • the present invention is an improvement in the just described lamp where the ionizable gas is a corrosive metal vapor such as cesium, rubidium, sodium and potassium.
  • a corrosive metal vapor such as cesium, rubidium, sodium and potassium.
  • These elements are quite eflicient as a source of radiation in the near infrared region of the spectrum. They must, however, be heated above room temperature before an electrical potential will ionize them and ignite the arc. But as the described lamp contains no heating means, an inert gas must be combined with the metal vapor as an ignition catalyst. This addition, however, alters the spectral emission of the lamp thereby diminishing, and in some applications, destroying its utility.
  • high, total, energy conversion efiiciency requires the high metal vapor pressures which are produced by heating of the vapor to temperatures as high as i000 C.
  • the described lamp has an integral source and reflector, the entire structure has to be heated to achieve the pressure necessary for high conversion efliciency when filled with a corrosive metal vapor.
  • Another object of the invention is to provide a short arc, high intensity metal vapor lamp capable of operat- 14 Claims- 3,497,742 Patented Feb. 24, 1970 ing at temperatures as high as 1000 C. for high energy conversion etiiciency.
  • Yet another object of the invention is to provide an improved metal vapor arc lamp having an envelope comprising a ceramic cylinder hermetically closed at its ends by a reflector and an optical window.
  • the present invention is a metal vapor arc lamp comprising a sealed arc tube confining an ionizable metal selected from the alkali metal group consisting of cesium, sodium, potassium and rubidium. Two spaced electrodes penetrate the arc tube to define an arc gap therewithin. Means are provided for heating the ionizable alkali metal to enable a voltage impressed across the arc gap to ionize the heated metal vapor and ignite the arc lamp.
  • the are tube is housed in a sealed envelope having a ceramic cylindrical section hermetically closed at each end by envelope members which respectively comprise an optical window and a reflector.
  • FIGURE 1 is a side view in cross section of the preferred embodiment of the present invention.
  • FIGURE 2 is a frontal view in elevation of the embodiment shown in FIGURE 1.
  • a metal vapor arc lamp having a ceramic, cylindrical section 10 which is preferably made of polycrystalline alumina and which is brazed to a metallic ring 12 having a flange 14.
  • Ring 12 and flange 14, which preferably are made of Kovar, serve as a section of the lamp envelope and as an exteriorly accessible lamp electrode, respectively.
  • Ring 12 is brazed to a metallic spacer 1-6 which in turn is brazed to window frame 18 also made of Kovar.
  • An optical window 20, in this case glass, is sealed within the window frame.
  • a concentric ring 22 is then joined to frame 16 by heliarc welding to an intermediary ring 23.
  • ceramic section 10 is brazed to another Kovar ring 24 through which a copper tubulation 26 extends.
  • a concentric ring 28 is fitted about ring 24 and brazed to ceramic section 10.
  • the free end of ring 28 is welded by heliarc to the free end of a ring 29 which in turn is brazed to Kovar ring 24.
  • a paraboloidic reflector 30 having an axial aperture is brazed to an inner edge of ring 24.
  • the reflector comprises a metal base having a very thin coating of gold, silver or platinum.
  • the geometry of the reflector produces a beam divergence limited to but 1 to 2.
  • a Kovar tube 32 is brazed to the reflector adjacent the aperture periphery.
  • the other end of tube 32 is welded to a cap 34, which in turn is brazed to a ceramic disc 36 having an aperture coaxial with that of reflector 30.
  • An electrode 38 extending through the aperture of disc 36, is aflixed thereto by means of sealing ring 40 to complete the lamp envelope.
  • a resistive heater wire 42 is wound about a portion of electrode 38. One end of the heater wire is aflixed to the electrode while the other end is aflixed to tube 32. In this manner both electrode 38 and tube 32 serve as exteriorly accessible lamp electrodes, as does flange 14.
  • Electrode 38 extends within the lamp envelope into an arc tube comprising a transparent, sapphire tube 44 sealed at each end by caps 46 which preferably are made of columbium. Electrode 38 terminates within the arc tube adjacent the terminus of another electrode 48 which extends through the other end cap 46 along the axis of electrode 38. The spacing between the electrodes defines an arc gap which approximates the diameter of the electrodes. This geometry places the lamp in the category commonly referred to as short are.
  • the arc tube is filled with cesium, sodium, potassium or rubidium. These alkali metals are in a solid state at room temperature. Upon being heated the metals change into their vapor state and typically assume a pressure of some ten standard atmospheres.
  • the other end of supports 50 are brazed to ring 12 providing electrical connection between electrode 48 and flange 14.
  • the arcuate shape of supports 50 permits stress release during high temperature lamp operation.
  • the envelope is evacuated through means of tubulation 26 which is then sealed.
  • the envelope may be backfilled with an inert gas.
  • the described metal vapor lamp is uniquely suited for use as an intense source of infrared radiation in the spectral region of from 7,500 to 12,000 angstroms.
  • full advantage can be taken of the capability of the metal vapor arc tube to operate at high temperatures to produce high vapor pressures which in turn yield increased infrared radiation at a sacrifice in total luminous emission.
  • a convert source less visible radiation is produced and more energy is converted to infrared radiation.
  • a metal vapor arc lamp comprising an envelope having a ceramic cylindrical section hermetically closed at each end by envelope members, a sealed arc tube housed Within said envelope and confining an ionizable metal selected from the alkali metal group consisting of cesium, sodium, potassium and rubidium, two spaced electrodes penetrating said are tube to define an arc gap therewithin, and means for heating said ionizable alkali metal to enable a voltage impressed across the arc gap to ionize the heated metal vapor and thereby ignite the arc lamp.
  • an ionizable metal selected from the alkali metal group consisting of cesium, sodium, potassium and rubidium
  • heating means comprises a resistor Wound in spaced relation about a portion of at least one of said electrodes.
  • said sealed arc tube comprises a sapphire tube and apertured columbium caps sealed to each end thereof.
  • one of said envelope members comprises an optical Window pervious to the passage of infrared radiation.
  • a metal vapor arc lamp having a sealed envelope comprising a ceramic cylindrical section hermetically closed at each end by envelope members, one of said members comprising a first metallic component and an optical Window and the other of said envelope members comprising a second metallic component and an apertured dielectric body, said envelope housing an arc tube which confines an ionizable metal selected from the alkali metal group consisting of cesium, sodium, potassium and rubidium; said are lamp further comprising a first electrode extending through said aperture dielectric body and into said are tube, a second electrode electrically and mechanically connected within said envelope to said first metallic component and extending into said arc tube adjacent said first electrode to define an arc gap therebetween, and means within said envelope electrically coupled to said second metallic component for heating said metal to ignite the arc lamp.
  • heating means comprises a resistor wound in spaced relation about a portion of said first electrode.
  • a metal vapor arc lamp of claim 7 wherein said are tube comprises a sapphire tube.
  • the metal vapor arc lamp of claim 7 wherein said sealed envelope comprises a reflector defining an aperture and wherein said arc tube extends through said reflector aperture.
  • the metal vapor arc lamp of claim 7 having an arcuate reflector aflixed to said metallic component.

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  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)
  • Discharge Lamp (AREA)
US691399A 1967-12-18 1967-12-18 Short metal arc tube mounted within a ceramic reflector envelope Expired - Lifetime US3497742A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US69139967A 1967-12-18 1967-12-18

Publications (1)

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US3497742A true US3497742A (en) 1970-02-24

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Country Status (4)

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US (1) US3497742A (de)
DE (1) DE1809443A1 (de)
FR (1) FR1597761A (de)
GB (1) GB1249353A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3684908A (en) * 1970-09-25 1972-08-15 Itt Sealed beam high intensity xenon lamp with cooling structure
US3715615A (en) * 1971-05-14 1973-02-06 Varian Associates Electrode support for arc lamps
US3725714A (en) * 1971-05-13 1973-04-03 Varian Associates Mounting ring and method for referencing members in a short arc lamp
DE3321939A1 (de) * 1982-06-24 1984-01-05 Egyesült Izzólámpa és Villamossági Részvénytársaság, 1340 Budapest Scheinwerfer fuer kraftfahrzeuge
US4724352A (en) * 1985-12-16 1988-02-09 Ilc Technology, Inc. Short-arc lamp with alternating current drive

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2333052A (en) * 1931-03-18 1943-10-26 Raytheon Mfg Co Electrical discharge device
US2820164A (en) * 1955-09-27 1958-01-14 Theodore C Retzer Electric heater for discharge lamps
US2982877A (en) * 1959-10-02 1961-05-02 Engelhard Hanovia Inc Arc lamp with sapphire sleeve
US3138731A (en) * 1962-09-12 1964-06-23 Norman C Beese Sealed beam high-intensity short arc lamp
US3283202A (en) * 1963-04-04 1966-11-01 Bell Telephone Labor Inc Gas discharge spectral lamp of 5350 angstroms
US3364374A (en) * 1964-09-28 1968-01-16 Gen Electric Compact source lamp having electrode construction providing arc stabilization
US3384798A (en) * 1966-04-26 1968-05-21 Gen Electric High pressure saturation vapor sodium lamp containing mercury

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2333052A (en) * 1931-03-18 1943-10-26 Raytheon Mfg Co Electrical discharge device
US2820164A (en) * 1955-09-27 1958-01-14 Theodore C Retzer Electric heater for discharge lamps
US2982877A (en) * 1959-10-02 1961-05-02 Engelhard Hanovia Inc Arc lamp with sapphire sleeve
US3138731A (en) * 1962-09-12 1964-06-23 Norman C Beese Sealed beam high-intensity short arc lamp
US3283202A (en) * 1963-04-04 1966-11-01 Bell Telephone Labor Inc Gas discharge spectral lamp of 5350 angstroms
US3364374A (en) * 1964-09-28 1968-01-16 Gen Electric Compact source lamp having electrode construction providing arc stabilization
US3384798A (en) * 1966-04-26 1968-05-21 Gen Electric High pressure saturation vapor sodium lamp containing mercury

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3684908A (en) * 1970-09-25 1972-08-15 Itt Sealed beam high intensity xenon lamp with cooling structure
US3725714A (en) * 1971-05-13 1973-04-03 Varian Associates Mounting ring and method for referencing members in a short arc lamp
US3715615A (en) * 1971-05-14 1973-02-06 Varian Associates Electrode support for arc lamps
DE3321939A1 (de) * 1982-06-24 1984-01-05 Egyesült Izzólámpa és Villamossági Részvénytársaság, 1340 Budapest Scheinwerfer fuer kraftfahrzeuge
US4724352A (en) * 1985-12-16 1988-02-09 Ilc Technology, Inc. Short-arc lamp with alternating current drive

Also Published As

Publication number Publication date
GB1249353A (en) 1971-10-13
FR1597761A (de) 1970-06-29
DE1809443A1 (de) 1969-07-17

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AS Assignment

Owner name: ILC TECHNOLOGY, INC, A CORP. OF CALIF., CALIFORNIA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:VARIAN ASSOCIATED INC, A CORP. OF DEL.;REEL/FRAME:004003/0869

Effective date: 19820402

Owner name: ILC TECHNOLOGY, INC, 399 JAVA DRIVE, SUNNYVALE, CA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:VARIAN ASSOCIATED INC, A CORP. OF DEL.;REEL/FRAME:004003/0869

Effective date: 19820402