EP0320933A2 - Pulsierend betriebene Metallhalogenlichtquelle - Google Patents

Pulsierend betriebene Metallhalogenlichtquelle Download PDF

Info

Publication number
EP0320933A2
EP0320933A2 EP88120992A EP88120992A EP0320933A2 EP 0320933 A2 EP0320933 A2 EP 0320933A2 EP 88120992 A EP88120992 A EP 88120992A EP 88120992 A EP88120992 A EP 88120992A EP 0320933 A2 EP0320933 A2 EP 0320933A2
Authority
EP
European Patent Office
Prior art keywords
metal halide
mercury
free
pulsed
arc lamp
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.)
Withdrawn
Application number
EP88120992A
Other languages
English (en)
French (fr)
Other versions
EP0320933A3 (de
Inventor
George J. English
Donald F. Garrity Jr.
Harold L. Rothwell Jr.
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 EP0320933A2 publication Critical patent/EP0320933A2/de
Publication of EP0320933A3 publication Critical patent/EP0320933A3/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/82—Lamps with high-pressure unconstricted discharge having a cold pressure > 400 Torr
    • H01J61/827—Metal halide arc lamps

Definitions

  • Conventional metal halide discharge light sources typically comprise a fused silica tube with two electrodes, a rare gas for starting, a charge of mercury, and a fill comprising one or more metal halide salts, generally the iodides.
  • a starting voltage of about 300V is applied across the electrode gap causing the contents of the arc tube to vaporize, resulting in a high temperature, high pressure, wall stabilized arc in a gas, consisting principally of mercury vapor, ionized metal atoms and iodine molecules.
  • the output spectrum (i.e. , the color of the discharge) of metal halide discharge lamps consists predominantly of the spectrum of the added metal halides. Color output for such lamps is tailored by varying the types of metal halides added to the arc tube. See for example, Waymouth, "Electric Discharge Lamps," Chapter 8, MIT Press, (1971).
  • the present invention represents a radical departure from the preexisting technology, namely the discovery of a metal halide arc lamp that does not employ mercury, the source cell of which can be formed from conventional glass, and which operates at near ambient temperature by means of a short duration, high pulse current.
  • the present invention is directed to a metal halide arc lamp which generates a flashing colored, preferably monochromatic, light.
  • the applications for such a source include signal and warning lights as well as applications in the visual aids field.
  • the lamp of the present invention can be easily fabricated from conventional borosilicate or alkali resistant glass (e.g. , Pyrex ® ) and requires no auxiliary heating, even though the emissive material, i.e. , the metal halide fill, is contained as a stable salt.
  • conventional borosilicate or alkali resistant glass e.g. , Pyrex ®
  • the emissive material i.e. , the metal halide fill
  • the pulsed metal halide lamp of the present invention comprises in combination:
  • Figure 1 illustrates a preferred configuration for the arc tube light source prepared according to the present invention.
  • Figure 2 represents the color output of an arc tube light source when lithium bromide is pulsed in accordance with the present invention.
  • Figure 3 illustrates one means for adjusting the color output of an arc source prepared in accordance with the teachings of the present invention, namely, the use of a coated reflector shield.
  • FIG. 1 A schematical drawing of the preferred arc tube light source of the present invention is shown in Figure 1.
  • the source of radiant energy in the lamp of the present invention comprises a light transmissive radiating chamber 10, which is preferably cylindrical, being defined in preferred embodiments by a tubular section of thin walled Pyrex ® glass.
  • Opposing electrodes 12, preferably formed of tungsten, are sealed into either end of the chamber 14, preferably using a vacuum sealing technique.
  • the emissive fill 16 comprises one or more metal halide salts, preferably alkali metal iodides or bromides, and this fill may be added to the radiating chamber 10 after one of the electrodes 12 has been sealed into the end of the chamber 14.
  • this fill is added as described, i.e. , before the addition of a second electrode 12, thus providing a source with no auxiliary tubing on the side.
  • An inert gas preferably argon, is then added to the source, and the second electrode 12 is sealed in place 14.
  • Such a construction is referred to as "tipless" which is generally not possible in traditional metal halide lamps.
  • An outer glass jacket (not illustrated) may be added to provide for convenient handling of the lamp.
  • a pulsed metal halide source prepared according to the present invention must have its cathode (negative (-) electrode) completely covered with the metal halide salt.
  • the metal halide salt is typically added as a granular or powdered fill which is thereafter melted and recrystallized around and over the cathode.
  • a natural gas torch is used to lightly heat up the cathode end of the cell during fabrication, causing melting of the metal halide salt around the cathode. Upon cooling, a solid mass of recrystallized (or fused) metal halide salt surrounds the cathode.
  • the cathode should be covered by at least about 0.5 mm of solidified metal halide salt. Lesser amounts will still work (providing the cathode is covered), but this represents a best estimate for the minimum amount of coverage required for consistently good performance.
  • the gap remaining between the anode and the top of the salt layer should range from about 3 to 10 mm for conventional arc tubes (about 10-15 mm x 3 mm).
  • a 1-2 kV potential with a time duration of a few microseconds (e.g. , 1-100, preferably 1-50, most preferably 1-10) is initially applied across the electrodes, which readily produces a low level of ionization of the argon and subsequent glow in the arc tube between the bare anode and the salt covering the cathode.
  • About a 300-400 volt potential is sustained across the gap between the anode and the salt during the high current pulse.
  • Figure 2 typifies what is observed when a cell prepared in accordance with the teachings of the present invention, and containing a preferred salt, lithium bromide, is pulsed in accordance with the above described procedures.
  • the arc glows a bluish-white color, while away from the central core 20, the color shifts toward blue-green, mixed with red.
  • a red colored light is emitted from the lithium vapor, as well as from the LiBr salt 24.
  • ionized argon atoms are accelerated toward the bottom electrode since that electrode is preferably the cathode.
  • Many collisions between the argon and metal halide salt occur as the argon migrates toward the bottom electrode. Some of these collisions will produce dissociation of the metal from the halide and eventual excitation of the metal. The resulting emission from the excited metal provides the desired effect, i.e. , colored light output.
  • such a metal rich region forms slightly above the salt level.
  • the metal can become excited so that emission is observed everywhere around the bottom electrode.
  • the lithium generates its resonance radiation at 610 and 670 nanometers wavelength, which is observed as a red color by the human eye.
  • lithium bromide emissive source In addition to the preferred lithium bromide emissive source, other metal halide salt systems such as sodium iodide and thallium iodide have been tested, and they exhibit a similar effect.
  • metal halide salt systems such as sodium iodide and thallium iodide have been tested, and they exhibit a similar effect.
  • the glow from the argon can be masked leaving visible only the emission from the salt region.
  • a mask 26 can be prepared from a reflector or a coated shield, which would be used to reflect energy back into the cell's interior as depicted in Figure 3. Since the pressure of the argon is only a fraction of an atmosphere and the preferred electrode gap is less than about 1 cm, the glow transfers into an arc within several microseconds.
  • the cell material can be Pyrex ® or alkali resistant glass which is more easily worked than fused silica which requires high heat for forming. Moreover, the geometry of the cell apparently does not affect the performance. Ellipsoidal, tubular, and spherical shaped cells have been utilized in the present invention, all with success.
  • the absence of a tip-off greatly improves the light distribution of the source in the present lamp.
  • the source also has fairly uniform light output in the horizontal plane.
  • the radiating region is effectively cylindrical so that no preforming of the glass is necessary; merely a straight section of glass tubing is sufficient.
  • the energy conservation with this source should be improved over an externally heated system since bulk vaporization of the salt will not be necessary.
  • the cell is basically cold.
  • Electrode maintenance should be improved since a diffuse contact at the cathode is guaranteed because of the salt coverage.
  • the salt disperses the plasma flow and provides many current paths to the electrode. Normally a gas arc will terminate on the cathode as a high current density spot which increases the local temperature of the electrode and contributes to erosion of the electrode.

Landscapes

  • Discharge Lamp (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
EP88120992A 1987-12-18 1988-12-15 Pulsierend betriebene Metallhalogenlichtquelle Withdrawn EP0320933A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US13540587A 1987-12-18 1987-12-18
US135405 1987-12-18

Publications (2)

Publication Number Publication Date
EP0320933A2 true EP0320933A2 (de) 1989-06-21
EP0320933A3 EP0320933A3 (de) 1990-05-23

Family

ID=22467964

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88120992A Withdrawn EP0320933A3 (de) 1987-12-18 1988-12-15 Pulsierend betriebene Metallhalogenlichtquelle

Country Status (2)

Country Link
EP (1) EP0320933A3 (de)
CA (1) CA1316975C (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4035561A1 (de) * 1989-11-08 1991-05-16 Matsushita Electric Works Ltd Lampe mit hochintensitaets-entladungsroehre
DE102008013607B3 (de) * 2008-03-11 2010-02-04 Blv Licht- Und Vakuumtechnik Gmbh Quecksilberfreie Metallhalogenid-Hochdruckentladungslampe

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA577060A (en) * 1959-06-02 W. L. Cumming Harry Electric discharge lamps
US3622217A (en) * 1969-06-30 1971-11-23 Xerox Corp Light producing system
US3840767A (en) * 1973-08-23 1974-10-08 Gen Electric Selective spectral output metal halide lamp
US4389201A (en) * 1979-03-12 1983-06-21 General Electric Company Method of manufacturing a lamp

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4035561A1 (de) * 1989-11-08 1991-05-16 Matsushita Electric Works Ltd Lampe mit hochintensitaets-entladungsroehre
DE102008013607B3 (de) * 2008-03-11 2010-02-04 Blv Licht- Und Vakuumtechnik Gmbh Quecksilberfreie Metallhalogenid-Hochdruckentladungslampe

Also Published As

Publication number Publication date
CA1316975C (en) 1993-04-27
EP0320933A3 (de) 1990-05-23

Similar Documents

Publication Publication Date Title
CA1201756A (en) Discharge lamp
JP2004172056A (ja) 放電ランプ装置用水銀フリーアークチューブ
JPS5954167A (ja) 低出力の高圧放電ランプ
US4874988A (en) Pulsed metal halide arc discharge light source
EP0330268B1 (de) Elektrische Lampe
EP0583122A1 (de) Bogenröhre und Entladungslampe
JP4037142B2 (ja) メタルハライドランプおよび自動車用前照灯装置
EP1363313A2 (de) Elektrische Lampe mit Kondensatreservoir und Verfahren zum Betrieb derselben
JP2775694B2 (ja) 放電ランプ
US20050122047A1 (en) Metal halide lamp, metal halide lamp operating device, and headlamp device for automobiles
US4850918A (en) Pulsed metal halide source
US4625149A (en) Metal vapor discharge lamp including an inner burner having tapered ends
GB2165392A (en) Arc tubes
EP0320933A2 (de) Pulsierend betriebene Metallhalogenlichtquelle
EP0183247A2 (de) Hochdruckmetallhalogenidbogenlampe mit Xenonpuffergas
JP2001313001A (ja) メタルハライドランプおよび自動車用前照灯装置
EP0101519B1 (de) Metal-dampf entladungs lampe
KR920010056B1 (ko) 편밀봉형 금속증기 방전등
CA1281761C (en) Metal halide arc tube and lamp having improved uniformity of azimuthal luminous intensity
JP4777594B2 (ja) 高圧放電灯およびこれを用いたランプユニット
GB2080020A (en) Electrical Light Source with a Metal Halide Discharge Tube and a Tungsten Filament Connected in Series with the Discharge Tube
JPH10283998A (ja) 直流ショートアークランプ
US5136208A (en) Metal halide lamp maintaining a high lumen maintenance factor over an extended operation period
KR100332636B1 (ko) 메탈헬라이드램프
JPH01264163A (ja) パルス作動メタルハライド光源

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19890111

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): BE DE FR GB NL

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): BE DE FR GB NL

17Q First examination report despatched

Effective date: 19920601

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19930507