US3668456A - Lamp having improved press seal - Google Patents

Lamp having improved press seal Download PDF

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Publication number
US3668456A
US3668456A US67699A US3668456DA US3668456A US 3668456 A US3668456 A US 3668456A US 67699 A US67699 A US 67699A US 3668456D A US3668456D A US 3668456DA US 3668456 A US3668456 A US 3668456A
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US
United States
Prior art keywords
ribbon
lamp
slot
rod
seal
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 - Lifetime
Application number
US67699A
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English (en)
Inventor
John W Anderson
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.)
GTE Sylvania Inc
Original Assignee
Sylvania Electric Products Inc
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 Sylvania Electric Products Inc filed Critical Sylvania Electric Products Inc
Application granted granted Critical
Publication of US3668456A publication Critical patent/US3668456A/en
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
    • 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

Definitions

  • Such lamp envelopes are usually sealed by a press seal at one or both ends thereof.
  • the press seal is formed by heating the open end of a tubular lamp envelope to the softening point of the glass and pressingthe softened end between a pair of aws.
  • lamps having press seals of the type to which this invention relates are tungsten halogen lamps and the arc tubes of arc discharge lamps, such as high pressure mercury vapor lamps and metal halide lamps.
  • the lamp envelopes of such lamps utilize press seals in order to prevent seal failures due either to thermal expansion of the glass or of the metal conductor embedded therein.
  • the high operating temperature of the lamps obviates the use of stem seals, such as are generally used in incandescent and fluorescent lamps, which have much lower operating temperatures;
  • the ribbon is connected to the lead-in wire by partial brazing or tacking.
  • a thin sheet of a suitable'm'etaL'usually platinum is placed between the ribbon and the lead-in wire, and the assembly is placed between a pair of resistance welding electrodes. The assembly is pressed between the electrodes and sufiicient electric current passed therethrough to heat and tack the elements together, with at least partial melting of the platinum sheet.
  • the bond between the ribbon and lead-in wire may be imroved during the press sealing operation if the silica glass is hot enough to melt additional platinum.
  • the brazing or tacking process may cause recrystallization of part of the molybdenum ribbon that is directly between the resistance welding electrodes. Recrystallization results in weakening of the ribbon which can then physically rupture because of thermal cycling that occurs during normal lamp operation. Or the recrystallization can cause high resistance electrical contact between the lead-in wire and the ribbon; the heat generated by the high resistance contact causes further degradation with resultant arcing and finally failure of the press sea].
  • a second disadvantage is that there may be insufiicient flow of the brazing metal to insure an adequately low electrical contact resistance. Point contact, as distinguished from a desired area contact, can result in the failure mentioned above.
  • Still another disadvantage of the prior art seal is the possibility of reaction of the brazing metal with materials present in the lamp fill. Such a reaction is possible because the glass does not form a hermetic seal with the lead-in wires; the hermetic seal is formed only in the region of the thin ribbon. Consequently it is possible for materials in gaseous form to penetrate the minuscule passage-that exists around the lead-in wire, as far as the ribbon connection at the end of the lead-in wire.
  • the arc tubes of metal halide lamps have a fill including light emitting metals such as are shown in US. Pat. 'Nos. 3,234,421, 3,334,261 and 3,407,327.
  • the metals are present in a gaseous state, as the halide.
  • the metallic halides can penetrate the seal and may react with the brazing metal to form an alloy having a eutectic temperature lower than the actual operating temperature of the seal.
  • a particular light emitting metal such as scandium iodide, could react with the glass to form silicon iodide, which, in turn, could react deleteriously with the platinum to form a platinum-silicon material. The latter material could cause seal failure in the manner mentioned above.
  • a lamp having a press seal in accordance with this invention has a refractory metalwire or rod, usually tungsten, disposed within a high silica glass enclosure which can be the lamp envelope of a high temperature incandescent lamp or the are longitudinal slot therein; securely held within the slot is one end of a thin refractory meta] ribbon, the ribbon itself being completely embedded within the press seal.
  • the ribbon is held within the slot by clamping pressure exerted by the sides of the a slot.
  • a longitudinal slot is formed in one end of the refractory metal wire.
  • the slot can be formed, for example, by grinding, machining, electrical disintegration, sonic cavitation or laser beam, although other methods may be equally suitable.
  • the slotmust have a sufficient opening to permit insertion of the ribbon therein and must have sufiicient depth to provide adequate contact area between the sides of the slot and the ribbon. Adequate contact area is necessary in order to provide low electrical contact resistance.
  • the sides of the slot are physically pressed together, preferably with heat but at a temperature lower than the recystallization temperature of the metals involved.
  • the pressureexerted must be sufficient to deform and close the slot but must not be so great as to crush or rupture the metal having the lower yield strength.
  • the metal having the higher yield strength is preferably heated to a higher temperature than the other metal.
  • the heating and joining are done in an inert or reducing atmosphere, in order to prevent oxidation of the metal.
  • the lamp has a high silica glass envelope 1 having press seals 2 at either end thereof. Disposed within envelope 1 are electrodes 3 at either end thereof, the electrodes consisting of tungsten coils 6 mounted on tungsten rods 7. In addition, starter electrode 4 is disposed at one end of envelope 1 adjacent one electrode 3. Starter electrode 4 comprises the inwardly projecting end of a tungsten or tantalum rod 8.
  • Embedded within press seals 2 are thin molybdenum ribbons 5, one ribbon for each electrode. Connection between each ribbon 5 and its respective tungsten rod 7 is established, prior to formation of press seal 2, by inserting the end of ribbon 5 into a slot at the end of the rod and pressing the sides of the slot together. The other end of each ribbon can then be connected to external lead-in wires by the same method.
  • prior art brazing methods may also be used in connecting the ribbon to the external lead-in wire, since the operating temperature of the seal thereat may be low enough to permit such a connection. For the same reason, brazing may be used toconnect the ribbon to the starter electrode 4.
  • envelope 1 is exhausted, filled and sealed by methods known to the art.
  • each tungsten rod 7 was 45 mils in diameter.
  • slot 9 was diametrically formed at one end of rod 7, the slot being 6 mils thick and about 60 to 80 mils deep.
  • Molybdenum ribbon 5 was rectangular, measuring about 3/16 inch by inch, and was about 1.3 mils thick at its center. A long end of ribbon 5 was centrally inserted into slot 9 and the rod was then placed between two socalled welding electrodes. The welding electrodes were made of thoriated tungsten and had a diameter at their tip of about 1/16 inch.
  • Rod 7 was so aligned between the welding electrodes that when the latter were closed, they exerted a substantially normal closing force on each side 10 of slot 9.
  • a closing force of 7 pounds was applied between the welding electrodes while sufficient electric current was passed therebetween to heat the slotted portion of rod 7 to about 1,500 or l,600 C.
  • the heat and pressure were sufficient to deform the sides of the slot and close them securely against the molybdenum ribbon, as shown in FIG. 4, while being insufiicient to cause recrystallization in the tungsten rod.
  • the pressure sufficient to extrude or crack the molybdenum ribbon.
  • Prior to closure of the slot there was poor heat transfer between rod 7 and ribbon 5, so ribbon 5 was not heated to the same extent as was rod 7.
  • the assembly was blanketed with forming gas percent hydrogen, 85 percent nitrogen) in order to prevent oxidation of any of the metal.
  • FIG. 2 shows an example of a tungsten halogen lamp utilizing a seal in accordance with the present invention.
  • the lamp has a high silica glass envelope 1 1 having a press seal 12 at one end thereof, a coiled tungsten filament 13 disposed within envelope l1 and a lamp fill including halogen.
  • Filament 13 has a coiled leg 14 at each end thereof, both legs 14 extending into press seal 12.
  • Each coiled leg 14 has a tungsten rod 16 securely inserted therein, the end of rod 16 protruding slightly beyond the end of leg 14 and being slotted.
  • Embedded within press seal 12 are two spaced apart molybdenum ribbons 15. Each ribbon 15 is fastened within the slot of a rod 16 in the manner described above. An external lead-in wire 18 is connected to each ribbon 15 in order to provide for connection to an external power source.
  • a lamp comprising: a high silica glass envelope having a press seal; a thin refractory metal ribbon entirely embedded within said press sea; a rod embedded within said press seal and extending interiorly into said envelope, said rod having a slot at the embedded end thereof, the sides of said slot being physically deformed in order to be securely closed on one end of said ribbon, thereby establishing a low resistance electrical connection between said ribbon and said rod.

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  • Vessels And Coating Films For Discharge Lamps (AREA)
US67699A 1970-08-28 1970-08-28 Lamp having improved press seal Expired - Lifetime US3668456A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US6769970A 1970-08-28 1970-08-28

Publications (1)

Publication Number Publication Date
US3668456A true US3668456A (en) 1972-06-06

Family

ID=22077777

Family Applications (1)

Application Number Title Priority Date Filing Date
US67699A Expired - Lifetime US3668456A (en) 1970-08-28 1970-08-28 Lamp having improved press seal

Country Status (6)

Country Link
US (1) US3668456A (de)
AU (1) AU3273371A (de)
CA (1) CA940584A (de)
DE (1) DE2142687A1 (de)
GB (1) GB1302340A (de)
ZA (1) ZA715437B (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3906275A (en) * 1973-05-04 1975-09-16 Philips Corp Electric lamp with electrolysis preventing apparatus
US4045645A (en) * 1976-03-05 1977-08-30 Gte Sylvania Incorporated Welding process for slotted tungsten rod
US4703221A (en) * 1986-04-18 1987-10-27 Ochoa Carlos G Electric lamp and method of making
US5038010A (en) * 1989-11-29 1991-08-06 Samsung Electron Devices Co., Ltd. Apparatus for welding leads to the electrodes of an ultrahigh voltage mercury vapor lamp
US6222647B1 (en) * 1995-10-30 2001-04-24 Seiko Epson Corporation Lamp unit and image reading apparatus using the same
EP1563524A2 (de) * 2002-11-07 2005-08-17 Advanced Lighting Technologies, Inc. Oxidationsgesch tzte metallfolie in verfahren
EP1635378A2 (de) * 2004-09-10 2006-03-15 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Elektrische Lampe mit Molybdänfolienabdichtung
WO2006046166A2 (en) * 2004-10-25 2006-05-04 Koninklijke Philips Electronics N.V. Electric lamp
US20090295291A1 (en) * 2002-11-07 2009-12-03 Tryggvi Emilsson Apparatus and methods for use of refractory abhesives in protection of metallic foils and leads
DE102006047389B4 (de) * 2006-10-06 2017-11-09 Osram Gmbh Lampe mit Metallfolienabdichtung, die einen geschlitzten Metallstift und eine damit verbundene Metallfolie umfasst

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8429740D0 (en) * 1984-11-24 1985-01-03 Emi Plc Thorn Lead wires in pinch seals

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US648516A (en) * 1899-06-29 1900-05-01 Karl Ochs Electric lamp with burner of the second class.
US2876377A (en) * 1955-09-01 1959-03-03 Westinghouse Electric Corp Ribbon seal and method of fabrication
US2883571A (en) * 1958-03-03 1959-04-21 Gen Electric Electric incandescent lamp
US3048741A (en) * 1960-08-24 1962-08-07 Duro Test Corp Arc lamp with self-ballasted arc tube and improved lumen maintenance
US3073985A (en) * 1960-04-21 1963-01-15 Westinghouse Electric Corp Arc tube and method
US3093769A (en) * 1959-05-15 1963-06-11 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Mixed-light electric lamp
CA683858A (en) * 1964-04-07 J. Kreps Thomas Electric lamp filament connection
US3360765A (en) * 1966-05-27 1967-12-26 British Lighting Ind Ltd Mounting of tungsten-halogen lamps

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA683858A (en) * 1964-04-07 J. Kreps Thomas Electric lamp filament connection
US648516A (en) * 1899-06-29 1900-05-01 Karl Ochs Electric lamp with burner of the second class.
US2876377A (en) * 1955-09-01 1959-03-03 Westinghouse Electric Corp Ribbon seal and method of fabrication
US2883571A (en) * 1958-03-03 1959-04-21 Gen Electric Electric incandescent lamp
US3093769A (en) * 1959-05-15 1963-06-11 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Mixed-light electric lamp
US3073985A (en) * 1960-04-21 1963-01-15 Westinghouse Electric Corp Arc tube and method
US3048741A (en) * 1960-08-24 1962-08-07 Duro Test Corp Arc lamp with self-ballasted arc tube and improved lumen maintenance
US3360765A (en) * 1966-05-27 1967-12-26 British Lighting Ind Ltd Mounting of tungsten-halogen lamps

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3906275A (en) * 1973-05-04 1975-09-16 Philips Corp Electric lamp with electrolysis preventing apparatus
US4045645A (en) * 1976-03-05 1977-08-30 Gte Sylvania Incorporated Welding process for slotted tungsten rod
US4703221A (en) * 1986-04-18 1987-10-27 Ochoa Carlos G Electric lamp and method of making
US5038010A (en) * 1989-11-29 1991-08-06 Samsung Electron Devices Co., Ltd. Apparatus for welding leads to the electrodes of an ultrahigh voltage mercury vapor lamp
US6222647B1 (en) * 1995-10-30 2001-04-24 Seiko Epson Corporation Lamp unit and image reading apparatus using the same
EP1563524A4 (de) * 2002-11-07 2008-12-10 Advanced Lighting Tech Inc Oxidationsgesch tzte metallfolie in verfahren
US20070082576A1 (en) * 2002-11-07 2007-04-12 Tryggvi Emilsson Oxidation-protected metallic foil and methods
EP1563524A2 (de) * 2002-11-07 2005-08-17 Advanced Lighting Technologies, Inc. Oxidationsgesch tzte metallfolie in verfahren
US20090295291A1 (en) * 2002-11-07 2009-12-03 Tryggvi Emilsson Apparatus and methods for use of refractory abhesives in protection of metallic foils and leads
US8264147B2 (en) 2002-11-07 2012-09-11 Advanced Lighting Technologies, Inc. Oxidation-protected metallic foil and methods
US8277274B2 (en) 2002-11-07 2012-10-02 Advanced Lighting Technologies, Inc. Apparatus and methods for use of refractory abhesives in protection of metallic foils and leads
EP1635378A2 (de) * 2004-09-10 2006-03-15 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Elektrische Lampe mit Molybdänfolienabdichtung
US20060055328A1 (en) * 2004-09-10 2006-03-16 Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh Electric lamp
EP1635378A3 (de) * 2004-09-10 2006-09-06 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Elektrische Lampe mit Molybdänfolienabdichtung
WO2006046166A2 (en) * 2004-10-25 2006-05-04 Koninklijke Philips Electronics N.V. Electric lamp
WO2006046166A3 (en) * 2004-10-25 2006-11-23 Koninkl Philips Electronics Nv Electric lamp
DE102006047389B4 (de) * 2006-10-06 2017-11-09 Osram Gmbh Lampe mit Metallfolienabdichtung, die einen geschlitzten Metallstift und eine damit verbundene Metallfolie umfasst

Also Published As

Publication number Publication date
CA940584A (en) 1974-01-22
GB1302340A (de) 1973-01-10
ZA715437B (en) 1972-05-31
DE2142687A1 (de) 1972-03-02
AU3273371A (en) 1973-03-01

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