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CA1241365A - Unsaturated vapor high pressure sodium lamp arc tube fabrication process - Google Patents

Unsaturated vapor high pressure sodium lamp arc tube fabrication process

Info

Publication number
CA1241365A
CA1241365A CA000448916A CA448916A CA1241365A CA 1241365 A CA1241365 A CA 1241365A CA 000448916 A CA000448916 A CA 000448916A CA 448916 A CA448916 A CA 448916A CA 1241365 A CA1241365 A CA 1241365A
Authority
CA
Canada
Prior art keywords
arc tube
getter
oxygen
electrode
high pressure
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
CA000448916A
Other languages
French (fr)
Inventor
John A. Scholz
Philip J. White
Robert S. White
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
Application granted granted Critical
Publication of CA1241365A publication Critical patent/CA1241365A/en
Expired legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00Apparatus 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
    • H01J9/38Exhausting, degassing, filling, or cleaning vessels
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00Gas-discharge or vapour-discharge lamps
    • H01J61/02Details
    • H01J61/24Means for obtaining or maintaining the desired pressure within the vessel
    • H01J61/26Means for absorbing or adsorbing gas, e.g. by gettering; Means for preventing blackening of the envelope

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Discharge Lamp (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)

Abstract

UNSATURATED VAPOR HIGH PRESSURE SODIUM LAMP ARC TUBE
FABRICATION PROCESS

ABSTRACT

An arc tube fabricating process wherein an oxygen-absorbing getter is affixed to at least one of a pair of electrodes, one of the electrodes is sealed into the end of a tubular ceramic envelope a dosage is deposited in the tubular ceramic envelope and the other one of the pair of electrodes is sealed into the other end of the tubular ceramic envelope.

Description

UNSATURATED VAPOR HIGH PRESSURE SODIUM LAP ARC TUBE
FABRICATION PROCESS

CROSS REYERENCE JO OTHER APPLICATIONS

The following concurrently filed Canadian Patent application relate to unsaturated vapor pressure type high pressure sodium lamps and the fabrication thereof:
448.953-5; 44%.9~-1; 448,954-3; and 448,915-2.

TEC~ICAL FrELD

This invention relates to high pressure sodium lamp of the unsaturated vapor type and more particularly to a process for fabricating arc tubes or unsaturated vapor high pressure sodium lamp.

BACKGROUND ART

In toe field of high p~es~ure sodium lamps, the bet known configuration includes a tubular ceramic arc tube disposed within an evacuated glass envelope. The arc tube is filled or dozed with a ware gay and an exce~ive amount of sodium and mercury. In other
- 2 -words. the arc tube ~a6 a saturated ~odiu~ fill because of the vell known tendency whereby large a~ount6 of sodium are lout during operation of the lamp. ~o~eover, such 6aturated type high pressure sodium lamp leave such to be desired due to the undesired variations in color lendition and operational voltage6 which are encountered.
In order to eliminate or a least reduce the above-mentioned undesirable characteristics. the so-called unsaturated vapor type high pressure sodium lamp way developed. Herein the co~truction i6 somewhat similar to the 6aturated type lamp except that the dotage of sodium, in particular. is greatly reduced. HoreoYer~ it was found that such a reduction in sodium content was possible so long as provision way jade for absorbing the excel oxygen which undesirably accompanied the Jill or rare gay which was di6pen6ed into the arc tube.
One of the techniques for effecting this absorption of undesired oxygen within the arc tube is to enclose an oxygen-ab~orbing getter therein along with toe usual dosage of sodium, mercury and a rare gay. One such structure is 6et forth and described in a concurrently filed application bearing Canadian Serial No.
~48,953-5, assigned to the As~igneee of the pre&ent application.
A jet forth therein, a getter material it located within the arc tube and in contact with the gases therein. T~u~, any undesired oxygen within the arc tube occurring during the sodium or mercury vaporization process or accompanying the admitted rare gay is absorbed by ths getter material and compound reformation it inhibited.
However, it has been found that even though the above-described technique ha provided great improvement over prior known unsaturated vapor high pressure sodium lamp construction and fabrication, there are still areas which leave something to be desired. More specifically, it has been found that direct contact between the enclosed getter material and the hotter portions of the tubular ceramic envelope of the arc tube wend to cause what appears to be a chemical reaction therebetween and an undesired darkened area of the ceramic envelope. Obviously, arc tube darkening is not a desirable condition.

OBJECTS AND SUMMARY OF THE INVENTION
..
An object of the present invention is to provide an improved unsaturated vapor type high pressure sodium lamp. Another object of the invention is to enhance an unsaturated vapor high pressure sodium lamp by improving the arc tube therein. Still another object of the invention is to provide an improved process for fabricating an arc tube employed in an unsaturated vapor type high pressure sodium lamp. A further object of the invention is to provide a process for fabricating an arc tube for an unsaturated vapor type h;gh pressure sodium lamp wherein undesired envelope discoloration is inhibited.
These and other objects, advantages and capabilities are ; achieved ir one aspect of the invention by a process for fabricating arc tubes for unsaturated vapor type high pressure sodium lamps wherein an oxygen-absorbing getter is affixed to one of a pair of electrodes, a tubular ceramic envelope is dosed with mercury, sodium and a rare gas and the electrodes are each sealed into an end of the tubular ceramic envelope with the getter therein and spaced from the envelope.

BRIEF DESCRIPTION OF THE DRAWINGS f FIG. l is an elevational view of a preferred form of unsaturated vapor type high pressure sodium lamp of the invention;
FIG. 2 is an exploded sectional view of an electrode Formed for attachment of an oxyyen-absorbing getter thereto and placement thereof within an arc tube; and FIG. 3 is a flow chart illustratin3 the process steps of fabricating an embodiment of an arc tube of the high pressure sodium lamp of FIG. l.

.
,, ' _4~ 3~3 BEST MODE FOR CARRYING OUT THE INVENTION

For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in conjunction with the accompanying drawings.
Referring to the drawings, FIG. 1 illustrates an unsaturated vapor high pressure sodium lamp having a hermetically sealed and evacuated glass envelope 5 formed to fit into an ordinary screw-type base member 7. A glass stem member 9 is sealed to the envelope 5 and projects therein. Electrical conductors, 11 and 13 respectively, are sealed into and pass through the stem member 9 to provide electrical connections from the interior to the exterior ox the glass envelope 5.
An electrically conductive support member 15 is affixed to one of the electrical conductors 11 and has a pair of crossbars 17 and lg affixed thereto at either end. Also, a plurality of spring-like members 21 are affixed to the support member 15 and formed for contact with the glass envelope 5. Moreover, a pair of getters 23 and 25 are attached to the support member 15 and serve to insure the ' 20 integrity of the evacuated envelope 5.
Disposed within the glass envelope 5 and supported by the crossbars 17 and 19 is an arc tube 27. This arc tube 27, preferably of a material such as polycrystalline alumina for example, includes ' an electrode 29 and 31 at either end thereof. One electrode 29 is affixed to and supported by the crossbar 17 while the other electrode 31 is insulatingly supported by the other crossbar 19, but electrically connected to the electrical conductor 13 passing through the stem member 9. Heat conserving elements 33 may be wrapped about the arc tube 27 at each end thereof in the vicinity of the electrodes 29 and 31 in order to reduce the heat differential thereat from the center of the arc tube 27.
Referring more specifically to FIX. 2 and the placement of an o~ygen-absorbing getter 37 therein, it is to be noted that the getter 37 is preferably in the form of a support member or substrate D-83-1~036 _5_ l 3~

49 whereon an oxygen-absorbing metal alloy 51 is affixed as by sintering. Preferably, the substrate 49 is of a material such as nickel plated iron and the sintered getter material is an alloy of metals selected from the group consisting of zirconium, aluminum, titanium9 scandium, ceriurn, lanthanum, thorium or yttrium. However, other rare earth oxides are suitable gettering materials for attachment to the substrate 49.
In the process of fabricating the previously-discussed arc tube?
27 of FIG. 1, an oxygen-absorbing gettering material or metal alloy 51 is sintered to a substrate 49 which is preferably in the form of a slitted apertured disc or getter 37. This getter is peferably formed for attachment to the shank portion 43 of the electrode member 39 such as by slipping the slitted apertured d;sc 37 onto the shank portion 43.
lS In the arc tube assembly, one of the electrodes 31 is sealed into one end of the ceramic envelope of the arc tube 27. Following, a dosing of sodium, mercury and a rare gas is deposited within thè
ceramic envelope of the arc tube 27. This dosing includes sodium and mercury in an amount which will become totally vaporized to provide a desired unsaturated vapor type high pressure sodium lamp.
Preferably, a sodium-mercury amalgam, which witl decompose within the arc tube 27, is deposited therein, and a rare gas is admitted into one end of the arc tube 27.
Thereafter, the other electrode, 29 of FIG. 1, having the oxygen-absorbing getter 37 affixed thereto is sealed into the other end of the arc tube 27. Moreover, this sealing of the electrodes 29 and 31 into the opposite ends of the tubular ceramic envelope of the arc tube 27 is preferably, not necessarily, effected by a frit I--sealing technique. Therein, a ceramic wafer, 41 of FIG. 2, is affixed to the electrode 39 and a glass frit material, not shown but preferably in the form of a wafer with a central hole, is utilized to effect the desired frit sealing of the electrodes 29 and 31 into the ends of the arc tube 27 in a manner such that the cathode portion 45 and the getter 37 are within the arc tube 27.
Referring to the flow chart of FIG. 3, it can be seen that the arc tube fabrication process is readily effected by sealing an , electrode into one end of a tubular ceramic envelope of the arc tube. Then a dose of sodium, mercury and rare gas is deposited into the envelope in an amount sufficient for vaporization and provision of an unsaturated. vapor type high pressure sodium lamp. Thereafter the other end of the tubular ceramic envelope is sealed with an electrode to which is affixed an oxygen gettering material to provide the desired arc tube.
Thus, a process has been provided for fabricating an arc tube for an unsaturated vapor type high pressure sodium lamp. Although one technique for affixing the getter within and spaced from the envelope has been provided, it is obvious that other methods of attachment could be used. For example, the getter could be welded to the cathode shank or dispensed or affixed to the cathode portion 45 of the electrode. In any event, the getter is spaced from the ceramic envelope of the arc tube.
While there has been shown and described what ;s at present considered the preferred embodiments of the invent;on, it w;ll be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention as dPfined by the appended claims.

.

. . ,

Claims (11)

WHAT IS CLAIMED IS:
1. In an unsaturated vapor type high pressure sodium lamp, an arc tube fabricating process comprising the steps of:
affixing an oxygen-absorbing getter to at least one of a pair of electrodes;
sealing one of said pair of electrodes into one end of a tubular ceramic envelope;
depositing a dosing of mercury, sodium and rare gas within said envelope; and sealing the other of said pair of electrodes having a getter affixed thereto into the other end of said tubular ceramic envelope to form an arc tube for an unsaturated vapor type high pressure sodium lamp.
2. The arc tube fabricating process of Claim 1 wherein said depositing of said dosing within said envelope includes the depositing of a sodium-mercury amalgam therein.
3. The arc tube fabricating process of Claim 1 wherein said oxygen-absorbing getter is in the form of a sintered metal affixed to a substrate and said getter is contiguous to at least one of said electrodes.
4. The process of Claim 1 including the steps of forming said oxygen-absorbing getter by sintering a metal to an apertured disc support, splitting said disc support and attaching said split disc support to said electrode with said electrode passing through said apertured disc.
5. The process of Claim 1 wherein said getter is in the form of a metal alloy selected from the group consisting of aluminum, zirconium, titanium, scandium, hafnium, cerium, lanthanum, thorium and yttrium.
6. The process of Claim 1 wherein said oxygen-absorbing getter is contiguous to at least one of said electrodes within and spaced from said tubular ceramic envelope.
7. The process of Claim 1 wherein said oxygen-absorbing getter is in the form of a zirconium-aluminum alloy sintered to an apertured split nickel plated iron substrate and said getter is affixed to an electrode by means of said apertured split substrate.
8. An arc tube fabricating process for unsaturated vapor type high pressure sodium lamps comprising the steps of:
sealing a first electrode into one end of a tubular ceramic envelope;
dosing said tubular ceramic envelope with a sodium-mercury amalgam and a rare gas;
attaching an oxygen-absorbing getter to a second electrode; and sealing said second electrode having an attached getter into the other end of said tubular ceramic envelope to provide an arc tube for an unsaturated vapor type high pressure sodium lamp.
9. The arc tube fabricating process of Claim 8 wherein said oxygen-absorbing getter is in the form of an apertured split supporting disc with an oxygen-absorbing material sintered thereto.
10. The arc tube fabricating process of Claim 8 wherein said step of attaching said oxygen-absorbing getter to said second electrode includes the step of spacing said getter from said tubular ceramic envelope.
11. The arc tube fabricating process of Claim 8 including the step of sintering a metal alloy selected from the group consisting of zirconium, aluminum, titanium, scandium, hafnium, cerium, lanthanum, thorium and yttrium to a substrate and affixing said substrate to said electrode.
CA000448916A 1983-03-10 1984-03-06 Unsaturated vapor high pressure sodium lamp arc tube fabrication process Expired CA1241365A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US47389483A 1983-03-10 1983-03-10
US473,894 1983-03-10

Publications (1)

Publication Number Publication Date
CA1241365A true CA1241365A (en) 1988-08-30

Family

ID=23881459

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000448916A Expired CA1241365A (en) 1983-03-10 1984-03-06 Unsaturated vapor high pressure sodium lamp arc tube fabrication process

Country Status (5)

Country Link
EP (1) EP0122050B1 (en)
JP (1) JPS59169036A (en)
AU (1) AU570434B2 (en)
CA (1) CA1241365A (en)
DE (1) DE3475854D1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8623296D0 (en) * 1986-09-27 1986-10-29 Emi Plc Thorn Hydrogen getter
US20070096649A1 (en) * 2005-10-28 2007-05-03 Roels Timothy J Electrode-mounted getter

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3384798A (en) * 1966-04-26 1968-05-21 Gen Electric High pressure saturation vapor sodium lamp containing mercury
US3453477A (en) * 1967-02-16 1969-07-01 Gen Electric Alumina-ceramic sodium vapor lamp
GB1211176A (en) * 1967-02-16 1970-11-04 Gen Electric High-pressure sodium vapor lamp
NL154865B (en) * 1967-03-31 1977-10-17 Philips Nv ELECTRIC GAS DISCHARGE LAMP WITH A COVER OF TIGHTLY INSERTED ALUMINUM OXIDE AND METHOD FOR MANUFACTURING SUCH GAS DISCHARGE LAMP.
NL7108465A (en) * 1970-06-24 1971-12-28
US3821585A (en) * 1973-04-30 1974-06-28 Westinghouse Electric Corp Tungsten halogen incandescent lamp with group iva metal getter and method of manufacture
JPS5818742B2 (en) * 1974-09-09 1983-04-14 日本電池株式会社 High pressure sodium lamp and its manufacturing method
US4075530A (en) * 1976-04-21 1978-02-21 Japan Storage Battery Company Limited High pressure sodium vapor lamp of unsaturated vapor pressure type
DE2704323A1 (en) * 1977-02-02 1978-08-03 Shigeru Suga Xenon lamp with constant light output - has ring shaped magnets behind electrode adsorbing metallic vapour and volatile matter
JPS53101874A (en) * 1977-02-18 1978-09-05 Hitachi Ltd High pressure sodium lamp
DE2848891C2 (en) * 1978-11-10 1982-12-30 Heimann Gmbh, 6200 Wiesbaden Flashlight
CA1214196A (en) * 1983-02-14 1986-11-18 Jack M. Strok Color rendition high pressure sodium arc tubes having an oxygen getter

Also Published As

Publication number Publication date
JPH0452582B2 (en) 1992-08-24
AU570434B2 (en) 1988-03-17
JPS59169036A (en) 1984-09-22
EP0122050A1 (en) 1984-10-17
DE3475854D1 (en) 1989-02-02
AU2547184A (en) 1984-09-13
EP0122050B1 (en) 1988-12-28

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