EP0375402A2 - Lampenquarzkolben mit Molybdanfolie mit Oxydationsbeständiger Fläche, gebildet durch Ionenimplantation - Google Patents

Lampenquarzkolben mit Molybdanfolie mit Oxydationsbeständiger Fläche, gebildet durch Ionenimplantation Download PDF

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Publication number
EP0375402A2
EP0375402A2 EP89313370A EP89313370A EP0375402A2 EP 0375402 A2 EP0375402 A2 EP 0375402A2 EP 89313370 A EP89313370 A EP 89313370A EP 89313370 A EP89313370 A EP 89313370A EP 0375402 A2 EP0375402 A2 EP 0375402A2
Authority
EP
European Patent Office
Prior art keywords
oxidation
lamp
lamp assembly
molybdenum
electrical lead
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.)
Granted
Application number
EP89313370A
Other languages
English (en)
French (fr)
Other versions
EP0375402A3 (de
EP0375402B1 (de
Inventor
Sandra Lee Madden
Mark D. Beschle
Roy C. Martin
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 EP0375402A2 publication Critical patent/EP0375402A2/de
Publication of EP0375402A3 publication Critical patent/EP0375402A3/de
Application granted granted Critical
Publication of EP0375402B1 publication Critical patent/EP0375402B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • H01J61/36—Seals between parts of vessels; Seals for leading-in conductors; Leading-in conductors
    • H01J61/366—Seals for leading-in conductors
    • H01J61/368—Pinched seals or analogous seals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
    • H01J5/32—Seals for leading-in conductors
    • H01J5/38—Pinched-stem or analogous seals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
    • H01J5/46—Leading-in conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/24—Manufacture or joining of vessels, leading-in conductors or bases
    • H01J9/28—Manufacture of leading-in conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/24—Manufacture or joining of vessels, leading-in conductors or bases
    • H01J9/32—Sealing leading-in conductors
    • H01J9/323—Sealing leading-in conductors into a discharge lamp or a gas-filled discharge device
    • H01J9/326—Sealing leading-in conductors into a discharge lamp or a gas-filled discharge device making pinched-stem or analogous seals

Definitions

  • This invention relates to electric lamps that utilize quartz lamp envelopes and, more particularly, to quartz lamp envelopes that utilize molybdenum components which are treated to inhibit oxidation.
  • Quartz is commonly used as a lamp envelope material in metal halide lamps and tungsten halogen incandescent lamps.
  • the quartz envelope defines a sealed lamp interior containing a filament or discharge electrodes and a suitable chemical fill. Electrical energy is supplied to the filament or to the electrodes by means of electrical feedthroughs which pass through the lamp envelope and are hermetically sealed to the quartz. It is critical to lamp operation that the seal remain intact throughout the life of the lamp.
  • quartz lamp envelopes It has been customary in quartz lamp envelopes to utilize a feedthrough configuration including a molybdenum ribbon, or foil, which passes through a press or pinch seal region of the quartz envelope.
  • the molybdenum foil is sufficiently wide to conduct the required lamp current and is extremely thin. Since the molybdenum foil is very thin, its thermal expansion is extremely small. Thus, the probability of seal failure due to differential thermal expansion is small.
  • the quartz is press sealed to the molybdenum foil, and a molybdenum electrical lead is welded to the external end of the foil.
  • the molybdenum foil and the molybdenum electrical lead have a tendency to oxidize to form MoO2 and MoO3 molybdenum oxides.
  • the molybdenum oxides initially form on the external electrical leads.
  • the oxidation then progresses to the molybdenum foil and causes a significant amount of stress on the press seal.
  • the stress is evident from Newton rings which appear at the point at which the leads are welded to the molybdenum foil.
  • the quartz press seal cracks, thereby causing the lamp to fail.
  • chromium is deposited on the molybdenum in a very high temperature pack cementation process. This is a very dangerous and inconvenient process. Pure hydrogen is passed through a tube furnace at 1200°C to initiate a reaction. The yield is very low, and devices are often damaged.
  • a lamp assembly comprising a quartz lamp envelope that encloses a sealed lamp interior, the lamp envelope including a press seal, and at least one molybdenum foil electrical feedthrough extending through the press seal to the lamp interior.
  • the molybdenum foil has an oxidation-inhibiting material embedded in a surface layer thereof.
  • the oxidation-inhibiting material is applied to the molybdenum foil feedthrough by ion implantation.
  • the oxidation-inhibiting material can be selected from the group consisting of chromium, aluminum, silicon, titanium, tantalum, palladium and combinations of these elements. Preferred materials include chromium and aluminum.
  • the thickness of the surface layer is typically in the range of about 20 to 100 angstroms.
  • the lamp assembly typically includes an external molybdenum electrical lead connected to the molybdenum foil.
  • the electrical lead has an oxidation-inhibiting coating thereon.
  • the oxidation-inhibiting coating is preferably formed by plasma-enhanced chemical vapor deposition.
  • Preferred materials include silicon carbide, silicon nitride and combinations thereof. Since the molybdenum electrical lead does not extend into the press seal, the added thickness is not detrimental to seal integrity.
  • the electrical lead has an oxidation-inhibiting material embedded into a surface layer thereof.
  • the surface layer can be formed by ion implantation of the materials identified above in connection with the treatment of the molybdenum foil feedthrough.
  • a method for making a lamp assembly comprises the steps of ion implanting an oxidation-inhibiting material into a surface layer of a molybdenum foil strip, and sealing the molybdenum foil strip into a press seal of a quartz lamp envelope to form an electrical feedthrough to a sealed lamp interior.
  • the method preferably includes the additional steps of forming an oxidation-inhibiting coating on an external electrical lead by plasma-enhanced chemical vapor deposition and attaching the coated electrical lead to the molybdenum foil strip.
  • a quartz lamp assembly in accordance with the present invention is shown in FIG. 1.
  • a lamp assembly 10 includes a quartz lamp envelope 12 which encloses a sealed lamp interior 14.
  • An incandescent filament 16 is mounted within the lamp interior 14 and is connected to electrical feedthroughs 18 and 20 which extend through a press seal region 22 of the lamp envelope 12 for connection to an external source of electrical energy.
  • the feedthrough 18 includes a molybdenum ribbon, or foil, 24 and a molybdenum electrical lead 26.
  • the feedthrough 20 includes a molybdenum foil 30 and a molybdenum electrical lead 32.
  • the electrical leads 26 and 32 are typically welded to molybdenum foils 24 and 30, respectively.
  • Opposite ends of filament 16 are electrically connected to foils 24 and 30.
  • the quartz of the lamp envelope 12 is sealed to foils 24 and 30 using a conventional press seal process so that the lamp interior 14 is isolated from the external environment.
  • a metal halide discharge lamp utilizing a quartz lamp envelope is shown in FIG. 2.
  • a generally cylindrical quartz lamp envelope 40 includes press seals 42 and 44 at opposite ends thereof.
  • Discharge electrodes 46 and 48 are coupled by electrode rods 50 and 52 to molybdenum foils 54 and 56, respectively.
  • Molybdenum electrical leads 58 and 60 which are coupled to molybdenum foils 54 and 56, respectively, provide means for connection of the electrodes to an external electrical source.
  • the molybdenum foils 54 and 56 are located in press seals 42 and 44, respectively.
  • quartz lamp assemblies can have various sizes, shapes and electrode or filament configurations.
  • a common feature is a press or pinch seal with a molybdenum foil which acts as an electrical feedthrough.
  • the width of the molybdenum foil is selected to carry the lamp operating current; and the thickness of the molybdenum foil is typically about 0.013-inch.
  • An oxidation-inhibiting material is preferably embedded in a surface layer of molybdenum foils 24, 30, 54, 56.
  • the oxidation-inhibiting material is embedded in the surface of the molydenum rather than forming a separate coating or surface layer. Therefore, the oxidation-ihibiting material does not increase the thickness of the molybdenum foils. As noted hereinabove, an increase in thickness is detrimental to seal integrity since it increases the probability of cracking caused by differential thermal expansion.
  • the oxidation-inhibiting material is embedded in the surface layer of the molybdenum foils by ion implantation.
  • Ion implantation is a well-known technique for introducing impurities into a bulk material such as a semiconductor or a metal.
  • a beam of ions is generated in a source and is directed with varying degrees of acceleration toward the target.
  • the momentum of the ions causes them to be embedded in the material of the target.
  • the depth of penetration depends on the energy of the ions.
  • An important advantage of ion implantation is that the ions of the oxidation-inhibiting material penetrate into the bulk of the molybdenum and do not increase its thickness.
  • Suitable oxidation-inhibiting materials include chromium, aluminum, silicon, titanium, tantalum, palladium and combinations of those metals. Preferred materials include chromium, aluminum and combinations thereof.
  • the surface layer in which the oxidation-inhibiting material is embedded has a thickness in the range of about 20 to 100 angstroms. The ion energy during implantation is selected to achieve the desired surface layer thickness. In an example of the ion implantation procedure, chromium ions are embedded into the molybdenum foil at an energy of 50 KeV and a dose of 1 x 1017/cm2.
  • Quartz press seals with molybdenum ribbons treated with chromium and aluminum have remained unchanged for over 100 hours at 650°C, while untreated control foils failed at an average of 5 to 10 hours.
  • a press seal is considered to have failed when a crack forms through the seal.
  • the molybdenum electrical leads 26, 32, 58, 60 that are attached to the external ends of the molybdenum foils can be provided with an oxidation-inhibiting surface layer using ion implantation in the same manner described hereinabove in connection with the molybdenum foils. It is important to provide oxidation-resistant surfaces on the electrical leads 26, 32, 58 and 60 even though the leads are outside the press seal, since oxidation progresses along the leads to the press seal, thereby causing seal failure.
  • an oxidation-inhibiting coating is applied to the molybdenum electrical leads by plasma-enhanced chemical vapor deposition (PECVD).
  • PECVD is a known process in which a coating is deposited on the surface of a substrate by means of a plasma. The thickness of the coating is determined by the deposition time, and the composition is determined by the plasma composition.
  • One advantage of the PECVD process is that the coating is uniformly applied to the surface of the electrical leads.
  • Suitable materials for PECVD coating of molybdenum electrical leads include silicon carbide and silicon nitride.
  • the oxidation-inhibiting coating has a thickness in the range of about 50 to 1000 angstroms.
  • the preferred coating is silicon carbide.
  • Silicon carbide coating of components by PECVD can be obtained from Spire Corporation of Bedford, Massachusetts. Molybdenum samples coated with silicon carbide have withstood temperatures up to 700°C in air for over 150 hours without any change, while untreated control samples of molybdenum last for only one hour under the same conditions before oxidizing.
  • the quartz lamp envelope is fabricated with molybdenum foils that are ion implanted with chromium, aluminum or combinations thereof to a depth of 20 to 100 angstroms.
  • the molybdenum electrical leads have a coating of silicon carbide deposited by PECVD. This combination provides very high resistance to oxidation and does not require changes in the lamp production process.
  • the oxidation-inhibiting materials are applied to the foils and to the electrical leads prior to the lamp assembly process. Oxidation of the molybdenum lamp components is significantly reduced, thereby allowing the lamp to have a much longer life with considerably fewer failures caused by molybdenum oxidation.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Semiconductor Lasers (AREA)
  • Physical Vapour Deposition (AREA)
EP19890313370 1988-12-21 1989-12-20 Lampenquarzkolben mit Molybdanfolie mit Oxydationsbeständiger Fläche, gebildet durch Ionenimplantation Expired - Lifetime EP0375402B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US28775588A 1988-12-21 1988-12-21
US287755 1988-12-21

Publications (3)

Publication Number Publication Date
EP0375402A2 true EP0375402A2 (de) 1990-06-27
EP0375402A3 EP0375402A3 (de) 1991-03-27
EP0375402B1 EP0375402B1 (de) 1998-03-18

Family

ID=23104197

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890313370 Expired - Lifetime EP0375402B1 (de) 1988-12-21 1989-12-20 Lampenquarzkolben mit Molybdanfolie mit Oxydationsbeständiger Fläche, gebildet durch Ionenimplantation

Country Status (4)

Country Link
EP (1) EP0375402B1 (de)
JP (1) JPH02267850A (de)
CA (1) CA2006129C (de)
DE (1) DE68928611T2 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5542867A (en) * 1993-12-08 1996-08-06 Ushiodenki Kabushiki Kaisha Process for connection of a molybdenum foil to a molybdenum lead portion and method of producing a hermetically enclosed part of a lamp using the process
WO2000010193A1 (en) * 1998-08-13 2000-02-24 Koninklijke Philips Electronics N.V. Electric lamp having a coated external current conductor
EP2107595A3 (de) * 2004-09-30 2009-10-28 Koninklijke Philips Electronics N.V. Elektrische Lampe und Metallfolie

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007012995A2 (en) 2005-07-26 2007-02-01 Philips Intellectual Property & Standards Gmbh Lamp and method of manufacturing a lamp
DE102007059340B4 (de) 2006-12-19 2019-10-24 Osram Gmbh Stromzuführungssystem

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7501272A (nl) * 1975-02-04 1976-08-06 Philips Nv Electrische lamp.
JPS5544786A (en) * 1978-09-27 1980-03-29 Hitachi Ltd Pressure sensor
NL183794B (nl) * 1979-02-26 Philips Nv Hogedrukkwikontladingslamp.
GB8429740D0 (en) * 1984-11-24 1985-01-03 Emi Plc Thorn Lead wires in pinch seals
WO1988002097A2 (en) * 1986-09-20 1988-03-24 Fraunhofer-Gesellschaft Zur Förderung Der Angewand Process for extending the resolution of a line or matrix camera

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5542867A (en) * 1993-12-08 1996-08-06 Ushiodenki Kabushiki Kaisha Process for connection of a molybdenum foil to a molybdenum lead portion and method of producing a hermetically enclosed part of a lamp using the process
EP0657912A3 (de) * 1993-12-08 1996-11-20 Ushio Electric Inc Verfahren zur Verbindung einer Molybden Folie mit einem Teil eines Molybden Leiters und Herstellungsmethode eines hermetisch eingeschossenen Lampenteils unter Verwendung dieser Verfahrens.
WO2000010193A1 (en) * 1998-08-13 2000-02-24 Koninklijke Philips Electronics N.V. Electric lamp having a coated external current conductor
US6265817B1 (en) * 1998-08-13 2001-07-24 U.S. Philips Corporation Electric lamp having a coated external current conductor
EP2107595A3 (de) * 2004-09-30 2009-10-28 Koninklijke Philips Electronics N.V. Elektrische Lampe und Metallfolie

Also Published As

Publication number Publication date
CA2006129C (en) 1994-03-08
EP0375402A3 (de) 1991-03-27
EP0375402B1 (de) 1998-03-18
JPH02267850A (ja) 1990-11-01
CA2006129A1 (en) 1990-06-21
DE68928611T2 (de) 1998-11-12
DE68928611D1 (de) 1998-04-23

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