EP0063393B1 - Method of producing a low-pressure mercury vapour discharge lamp - Google Patents

Method of producing a low-pressure mercury vapour discharge lamp Download PDF

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Publication number
EP0063393B1
EP0063393B1 EP82200395A EP82200395A EP0063393B1 EP 0063393 B1 EP0063393 B1 EP 0063393B1 EP 82200395 A EP82200395 A EP 82200395A EP 82200395 A EP82200395 A EP 82200395A EP 0063393 B1 EP0063393 B1 EP 0063393B1
Authority
EP
European Patent Office
Prior art keywords
amalgam
container
discharge vessel
bismuth
indium
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
Application number
EP82200395A
Other languages
German (de)
French (fr)
Other versions
EP0063393A1 (en
Inventor
Antonius Johannes Alberta Van Stratum
Pieter Hokkeling
Johannes Gerardus Van Os
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.)
Koninklijke Philips NV
Original Assignee
Philips Gloeilampenfabrieken NV
Koninklijke Philips Electronics NV
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 Philips Gloeilampenfabrieken NV, Koninklijke Philips Electronics NV filed Critical Philips Gloeilampenfabrieken NV
Publication of EP0063393A1 publication Critical patent/EP0063393A1/en
Application granted granted Critical
Publication of EP0063393B1 publication Critical patent/EP0063393B1/en
Expired 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
    • H01J61/70—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr
    • H01J61/72—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr having a main light-emitting filling of easily vaporisable metal vapour, e.g. mercury
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/24—Means for obtaining or maintaining the desired pressure within the vessel
    • H01J61/28—Means for producing, introducing, or replenishing gas or vapour during operation of the lamp

Definitions

  • the invention relates to a method of producing a low-pressure mercury vapour discharge lamp having a discharge vessel, said method comprising the steps of
  • the invention has for its object to provide a method for producing a low-pressure mercury vapour discharge lamp which mitigates the above drawbacks, wherein the release of unwanted gases is prevented from occurring when said container is opened.
  • said method is characterized in that said amalgam of indium and bismuth is formed in the closed metal container by heating a spherical member of bismuth substantially wholly enveloped by a ductile mass of indium amalgam.
  • the container is tightly enclosing the indium-bismuth amalgam. Unwanted trapping of gas is avoided.
  • a further advantage of said method is that no separate heating step for making a syrupy amalgam liquid in the container is necessary.
  • the temperature of the discharge vessel is relatively high due to other steps in said process, such as the sealing and pumping steps of the discharge vessel.
  • a spherical bismuth member is positioned on a ductile tablet of indium amalgam present in the container. After heating for some time, a proper mixing of said elements results.
  • Said spherical members and tablets can be mass-produced in a simple way. Further the spheres and tablets can be easily positioned in the container in a mechanized process.
  • the method can be used with great advantage in small discharge lamps, for example in lamps having a shape as described in DE-A 2,940,563.
  • the temperature in the discharge vessel is rather high during operation.
  • the presence of an outer envelope reduces the heat discharge from the discharge vessel.
  • An opening of the container is performed, as mentioned in the foregoing, wholly separately from the further operations on the lamp, it is optionally possible to market discharge vessels which are closed in a vacuum-tight manner, but which still include a closed container.
  • This container may then be opened later at a suitable moment, for example by the buyer of these "lamps".
  • This operation is namely so simple (particularly if high-frequency inductive heating or a converging laser beam is used) that a buyer can perform these operations without elaborate equipment. All this has the advantage that during transportation of the "lamps” the amalgam-forming metal or the amalgam-forming alloy cannot become detached from the lamp wall; should these "lamps" containing amalgams break during transportation no mercury vapour can be released into the environment.
  • the invention therefore also relates to discharge vessels of this type.
  • reference numeral 1 denotes the wall of a tubular discharge vessel of a low-pressure mercury vapour discharge lamp, stems 2 and 3 with electrodes 4 and 5, respectively being provided one at each end.
  • the inteior wall of the discharge vessel is coated with a luminescent layer 6 consisting, for example, of a mixture of trivalent europium-activated yttrium-oxide and trivalent terbium-activated cerium magnesium aluminate.
  • a metal wire 7, which is connected to a metal container 8 located behind the electrodes is welded to one of the current supply wires of electrode 4.
  • the wall portion near said container (the foot 9 of the stem 2) is provided with an amalgam. Said amalgam is applied by means of a method in accordance with the invention.
  • the amalgam is provided in a cool spot, which is advantageous for the control of the mercury vapour pressure in the discharge vessel, behind the electrode 4.
  • the interior wall of a tube is first coated by means of a known method with a luminescent layer, whereafter the stems are connected in a vacuum-tight manner to the wall of the tube.
  • Said stems have a closed metal container 8 which contains an amalgam.
  • the discharge vessel is exhausted (by means of an exhaust tube 10 connected to one of the stems), the rare gas atmosphere is established and the discharge vessel is closed in a vacuum-tight manner by sealing the exhaust tube.
  • the metal container 8 opened by directing a focussed laser beam onto the wall of the container so as to make an opening therein. At least a portion of the amalgam leaves the container through the opening as a syrupy liquid and moves to the foot 9 of the stem, where it adheres.
  • Fig. 2 shows one end of a discharge vessel at the moment at which all operations on the lamps except the release of the amalgam have been finished.
  • Said amalgam is in the container 8 which is still in the closed condition.
  • the container 8 is formed by two sheet metal portions 8a and 8b (for example consisting of iron or nickel) which are welded together, 8b having been provided with a recess in which an amalgam 11 consisting of indium, bismuth and mercury is provided.
  • the amalgam is obtained by heating a small sphere of bismuth which is enclosed by a quantity of ductile alloy of indium and mercury. It has been found that the bismuth is then very rapidly absorbed by the alloy and forms a homogenous somewhat liquid compound.
  • the metal portions 8a and 8b fit around amalgam 11 in such a way that no unwanted gasses are trapped in the container.
  • the container 8 is opened by means of a laser arranged outside the discharge vessel. An opening is drilled in a portion 12 of 8a by focussing the laser beam. The temperature then increases to such a value that a portion of the amalgam flows from the container 8.
  • the wall portion 9 where a portion of the amalgam arrives is located at only a few mm (for example 2 mm) from portion 12.
  • the use of a converging laser beam to form the opening has the advantage that the further portions (for example 1 and 2) of the glass wall of the discharge vessel are not attacked by the laser light.
  • the energy of the laser light can be concentrated such that even amalgam-forming components having a low.vapour pressure (such as indium or bismuth) become syrupy when the opening is formed.
  • the container is inductively heated, a weak spot having been provided in the container wall where the container is opened.
  • a practical embodiment of a lamp shown in Fig. 1 produced by means of a method in accordance with the invention contained 26.8 mg Bi, 13.2 mg In and 3.0 mg Hg (in wt.% 62.3% Bi, 30.7% In, 7% Hg).
  • the container was formed of two metal portions which are welded together and one of which is provided with a recess. An opening (diameter 0.47 mm) was formed in the container by means of a pulsed Nd-YAG laser (pulse energy approximately 2 J).
  • the lamp having argon, 267 Pa, as rare gas filling

Landscapes

  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)

Description

  • The invention relates to a method of producing a low-pressure mercury vapour discharge lamp having a discharge vessel, said method comprising the steps of
    • - providing in the discharge vessel and near a portion of its interior wall a closed container to be opened after the discharge vessel has been closed in a vacuum-tight manner
    • - establishing thereafter the desired gas atmosphere in the discharge vessel and
    • - closing said discharge vessel in a vacuum-tight manner,

    an amalgam of indium and bismuth being present in the closed container in order that an amount of bismuth-indium alloy leaves it when it is opened and moved towards the neighbouring portion of the interior wall.
  • In EP-A-0 050 509, which is relevant in pursuance of Article 54(3) EPC, such a method for producing a low-pressure mercury vapour discharge lamp is described in which a mercury dispenser is used comprising two metallic walls shaped and sealed together so as to form a heat- rupturable container for mercury or an amalgam. The walls of said container form a part of the cathode disintegration shield of the cathode. In said method the amalgam-forming metal or alloy (such as the indium-bismuth alloy) are not exposed to a hot, oxygen-containing atmosphere during the lamp production process, so that no oxide layer is formed on said alloy or metal, respectively. Namely, during the entire production process the metal or the alloy is located in the still closed container which is not opened until the discharge vessel has been closed in a vacuum-tight manner.
  • However in said container also unwanted gases, such as oxygen, nitrogen etc. are present. If said container is opened (after closing the discharge vessel) releasing the amalgam or the amalgam forming matter said gases are introduced in the discharge vessel as well. Such gases have a bad influence on the light output and the ignition of the clamp.
  • The invention has for its object to provide a method for producing a low-pressure mercury vapour discharge lamp which mitigates the above drawbacks, wherein the release of unwanted gases is prevented from occurring when said container is opened.
  • According to the invention said method is characterized in that said amalgam of indium and bismuth is formed in the closed metal container by heating a spherical member of bismuth substantially wholly enveloped by a ductile mass of indium amalgam.
  • In the method according to the invention the container is tightly enclosing the indium-bismuth amalgam. Unwanted trapping of gas is avoided. A further advantage of said method is that no separate heating step for making a syrupy amalgam liquid in the container is necessary. During the high-speed lamp-making process the temperature of the discharge vessel is relatively high due to other steps in said process, such as the sealing and pumping steps of the discharge vessel.
  • In a practical embodiment of the method a spherical bismuth member is positioned on a ductile tablet of indium amalgam present in the container. After heating for some time, a proper mixing of said elements results. Said spherical members and tablets can be mass-produced in a simple way. Further the spheres and tablets can be easily positioned in the container in a mechanized process.
  • In low-pressure mercury vapour discharge lamps produced by means of the method the mercury vapour pressure remains reasonably stable of a wide temperature range around 6 x 10-3 Torr (0.8 Pascal). Lamps of this type, having an amalgam, are, for example, suitable for use in places where the ambient temperature is high.
  • In addition, the method can be used with great advantage in small discharge lamps, for example in lamps having a shape as described in DE-A 2,940,563. In this type of lamp the temperature in the discharge vessel is rather high during operation. The presence of an outer envelope reduces the heat discharge from the discharge vessel.
  • An opening of the container is performed, as mentioned in the foregoing, wholly separately from the further operations on the lamp, it is optionally possible to market discharge vessels which are closed in a vacuum-tight manner, but which still include a closed container. This container may then be opened later at a suitable moment, for example by the buyer of these "lamps". This operation is namely so simple (particularly if high-frequency inductive heating or a converging laser beam is used) that a buyer can perform these operations without elaborate equipment. All this has the advantage that during transportation of the "lamps" the amalgam-forming metal or the amalgam-forming alloy cannot become detached from the lamp wall; should these "lamps" containing amalgams break during transportation no mercury vapour can be released into the environment. The invention therefore also relates to discharge vessels of this type.
  • The invention will now be further described by way of example with reference to a drawing in which
    • Fig. 1 shows an embodiment of a low-pressure mercury vapour discharge lamp produced by means of a method in accordance with the invention and
    • Fig. 2 shows one end, partly in cross-sectional view, of a discharge vessel containing a container still to be opened.
  • In Fig. 1 reference numeral 1 denotes the wall of a tubular discharge vessel of a low-pressure mercury vapour discharge lamp, stems 2 and 3 with electrodes 4 and 5, respectively being provided one at each end. The inteior wall of the discharge vessel is coated with a luminescent layer 6 consisting, for example, of a mixture of trivalent europium-activated yttrium-oxide and trivalent terbium-activated cerium magnesium aluminate. A metal wire 7, which is connected to a metal container 8 located behind the electrodes is welded to one of the current supply wires of electrode 4. The wall portion near said container (the foot 9 of the stem 2) is provided with an amalgam. Said amalgam is applied by means of a method in accordance with the invention. The amalgam is provided in a cool spot, which is advantageous for the control of the mercury vapour pressure in the discharge vessel, behind the electrode 4.
  • During the production of the lamp the interior wall of a tube is first coated by means of a known method with a luminescent layer, whereafter the stems are connected in a vacuum-tight manner to the wall of the tube. Said stems have a closed metal container 8 which contains an amalgam. Thereafter the discharge vessel is exhausted (by means of an exhaust tube 10 connected to one of the stems), the rare gas atmosphere is established and the discharge vessel is closed in a vacuum-tight manner by sealing the exhaust tube. Not until thereafter is the metal container 8 opened by directing a focussed laser beam onto the wall of the container so as to make an opening therein. At least a portion of the amalgam leaves the container through the opening as a syrupy liquid and moves to the foot 9 of the stem, where it adheres.
  • Fig. 2 shows one end of a discharge vessel at the moment at which all operations on the lamps except the release of the amalgam have been finished. Said amalgam is in the container 8 which is still in the closed condition. The container 8 is formed by two sheet metal portions 8a and 8b (for example consisting of iron or nickel) which are welded together, 8b having been provided with a recess in which an amalgam 11 consisting of indium, bismuth and mercury is provided. The amalgam is obtained by heating a small sphere of bismuth which is enclosed by a quantity of ductile alloy of indium and mercury. It has been found that the bismuth is then very rapidly absorbed by the alloy and forms a homogenous somewhat liquid compound. The metal portions 8a and 8b fit around amalgam 11 in such a way that no unwanted gasses are trapped in the container. The container 8 is opened by means of a laser arranged outside the discharge vessel. An opening is drilled in a portion 12 of 8a by focussing the laser beam. The temperature then increases to such a value that a portion of the amalgam flows from the container 8.
  • In a practical embodiment, the wall portion 9 where a portion of the amalgam arrives is located at only a few mm (for example 2 mm) from portion 12. The use of a converging laser beam to form the opening has the advantage that the further portions (for example 1 and 2) of the glass wall of the discharge vessel are not attacked by the laser light. Moreover, the energy of the laser light can be concentrated such that even amalgam-forming components having a low.vapour pressure (such as indium or bismuth) become syrupy when the opening is formed.
  • In an alternative embodiment the container is inductively heated, a weak spot having been provided in the container wall where the container is opened.
  • A practical embodiment of a lamp shown in Fig. 1 produced by means of a method in accordance with the invention contained 26.8 mg Bi, 13.2 mg In and 3.0 mg Hg (in wt.% 62.3% Bi, 30.7% In, 7% Hg). The container was formed of two metal portions which are welded together and one of which is provided with a recess. An opening (diameter 0.47 mm) was formed in the container by means of a pulsed Nd-YAG laser (pulse energy approximately 2 J). At an applied power of 13 W the lamp (having argon, 267 Pa, as rare gas filling) had a luminous flux of approximately 900 Lumen.

Claims (1)

  1. Method of producing a low-pressure mercury vapour discharge lamp having a discharge vessel, said method comprising the steps of
    - providing in the discharge vessel and near a portion of its interior wall a closed container to be opened after the discharge vessel has been closed in a vacuum-tight manner
    - establishing thereafter the desired gas atmosphere in the discharge vessel and
    - closing said discharge vessel in a vacuum-tight manner,

    an amalgam of indium and bismuth being present in the closed container in order that an amount of bismuth-indium alloy leaves it when it is opened and moves towards the neighbouring portion of the interior wall, said method being characterized in that said amalgam of indium and bismuth is formed in the closed metal container by heating a spherical member of bismuth substantially wholly enveloped by a ductile mass of indium amalgam.
EP82200395A 1981-04-16 1982-03-31 Method of producing a low-pressure mercury vapour discharge lamp Expired EP0063393B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL8101885A NL8101885A (en) 1981-04-16 1981-04-16 METHOD FOR MANUFACTURING A LOW-PRESSURE MERCURY DISCHARGE LAMP AND LOW-PRESSURE MERCURY DISCHARGE LAMP Manufactured by that method.
NL8101885 1981-04-16

Publications (2)

Publication Number Publication Date
EP0063393A1 EP0063393A1 (en) 1982-10-27
EP0063393B1 true EP0063393B1 (en) 1986-06-18

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ID=19837367

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Application Number Title Priority Date Filing Date
EP82200395A Expired EP0063393B1 (en) 1981-04-16 1982-03-31 Method of producing a low-pressure mercury vapour discharge lamp

Country Status (5)

Country Link
EP (1) EP0063393B1 (en)
JP (1) JPS57180040A (en)
CA (1) CA1194096A (en)
DE (1) DE3271746D1 (en)
NL (1) NL8101885A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7952286B2 (en) 2006-11-03 2011-05-31 Osram Gesellschaft mit beschränkter Haftung Mercury source

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5274305A (en) * 1991-12-04 1993-12-28 Gte Products Corporation Low pressure mercury discharge lamp with thermostatic control of mercury vapor pressure
US5374871A (en) * 1992-07-21 1994-12-20 General Electric Company Annular dosing capsule for electric discharge lamp and method of dosing the lamp using the capsule
GB9424262D0 (en) * 1994-12-01 1995-01-18 Masonlite Ltd Apparatus for providing radiation
GB2295721B (en) * 1994-12-01 1998-11-11 Masonlite Ltd Apparatus for providing radiation
US7625258B2 (en) 2006-03-16 2009-12-01 E.G.L. Company Inc. Lamp electrode and method for delivering mercury
EP2147458A1 (en) * 2007-05-09 2010-01-27 Koninklijke Philips Electronics N.V. Low-pressure mercury vapor discharge lamp with amalgam capsule having amalgam chamber
RU2465081C1 (en) * 2011-06-24 2012-10-27 Открытое акционерное общество Акционерная холдинговая компания "Всероссийский научно-исследовательский и проектно-конструкторский институт металлургического машиностроения имени академика Целикова" (ОАО АХК "ВНИИМЕТМАШ") Method of making cold-rolled sheets from aluminium and its alloys
JP7072786B2 (en) * 2017-09-29 2022-05-23 岩崎電気株式会社 Low-pressure mercury lamp and its manufacturing method

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0050509A1 (en) * 1980-10-22 1982-04-28 Sale Tilney Technology Plc Mercury dispenser for electric discharge lamps, article and method for manufacturing such a dispenser and electric discharge lamp provided therewith

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB967685A (en) * 1962-03-28 1964-08-26 Hivac Ltd Improvements in or relating to gas discharge tubes
GB1419099A (en) * 1972-08-11 1975-12-24 Thorn Electrical Ind Ltd Manufacturing electric devices having sealed envelopes
JPS5045476A (en) * 1973-08-29 1975-04-23
AR206705A1 (en) * 1974-03-21 1976-08-13 Philips Nv METHOD OF MANUFACTURING A MERCURY VAPOR DISCHARGE LAMP AND A LAMP MADE BY SUCH METHOD
US3860852A (en) * 1974-04-04 1975-01-14 Gte Sylvania Inc Fluorescent lamp containing amalgam-forming material
NL183687C (en) * 1978-10-11 1988-12-16 Philips Nv LOW-PRESSURE MERCURY DISCHARGE LAMP.

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0050509A1 (en) * 1980-10-22 1982-04-28 Sale Tilney Technology Plc Mercury dispenser for electric discharge lamps, article and method for manufacturing such a dispenser and electric discharge lamp provided therewith

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7952286B2 (en) 2006-11-03 2011-05-31 Osram Gesellschaft mit beschränkter Haftung Mercury source

Also Published As

Publication number Publication date
JPS57180040A (en) 1982-11-05
DE3271746D1 (en) 1986-07-24
EP0063393A1 (en) 1982-10-27
NL8101885A (en) 1982-11-16
CA1194096A (en) 1985-09-24

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