EP1659614A2 - Gasentladung mit Emission im UV-A-Gebiet und Fluoreszenzlampe die diese Gasentladung enthält - Google Patents

Gasentladung mit Emission im UV-A-Gebiet und Fluoreszenzlampe die diese Gasentladung enthält Download PDF

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Publication number
EP1659614A2
EP1659614A2 EP05255050A EP05255050A EP1659614A2 EP 1659614 A2 EP1659614 A2 EP 1659614A2 EP 05255050 A EP05255050 A EP 05255050A EP 05255050 A EP05255050 A EP 05255050A EP 1659614 A2 EP1659614 A2 EP 1659614A2
Authority
EP
European Patent Office
Prior art keywords
radical
radiation
group
generating
radicals
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.)
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Application number
EP05255050A
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English (en)
French (fr)
Other versions
EP1659614A3 (de
Inventor
Joseph Darryl Michael
Nikolai Alexandrovich Timofeev
Mikhail Alexeevich Khodorkovshii
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.)
General Electric Co
Original Assignee
General Electric Co
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
Priority claimed from RU2004125185/09A external-priority patent/RU2336592C2/ru
Application filed by General Electric Co filed Critical General Electric Co
Publication of EP1659614A2 publication Critical patent/EP1659614A2/de
Publication of EP1659614A3 publication Critical patent/EP1659614A3/de
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/12—Selection of substances for gas fillings; Specified operating pressure or temperature
    • H01J61/14—Selection of substances for gas fillings; Specified operating pressure or temperature having one or more carbon compounds as the principal constituents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/38—Devices for influencing the colour or wavelength of the light
    • H01J61/42—Devices for influencing the colour or wavelength of the light by transforming the wavelength of the light by luminescence
    • H01J61/44—Devices characterised by the luminescent material
    • 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
    • H01J61/76—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr having a filling of permanent gas or gases only

Definitions

  • the present invention relates to discharge lamps having a source of emission in the wavelength range in the UV-A radiation.
  • the present invention relates to fluorescent lamps having a gas discharge UV-A radiation source and emitting in the visible electromagnetic spectrum.
  • Mercury vapor discharge fluorescent lamps have been used extensively for lighting purposes.
  • a small amount of mercury and an inert gas such as argon, krypton, or xenon, are contained in a sealed glass tube having an electrode at each of its ends.
  • an inert gas such as argon, krypton, or xenon
  • a discharge is generated between the electrodes, and the mercury atoms are excited to a high-energy state.
  • the mercury atoms Upon returning to the ground state, the mercury atoms produce ultraviolet (“UV") radiation, which consists essentially of emission at 254 nm and 185 nm.
  • UV radiation ultraviolet
  • one or more phosphors are provided on the inner wall of the glass tube to absorb this UV radiation and emit in the wavelength range.
  • UV-A means UV radiation having wavelengths in the range from about 300 nm to about 400 nm.
  • mercury vapor discharge fluorescent lamps are low because of the large difference between the wavelengths of radiation emitted by mercury and those of light emitted by the phosphors. In addition, mercury in lamps that are finally discarded presents a source of pollution.
  • US Patent 6,040,658 describes a mercury-free discharge lamp wherein UV-A emission having wavelength of about 306 nm is obtained from excited OH radicals, which are formed from dissociation of alkali earth metal hydroxides, such as Ca(OH) 2 or Mg(OH) 2 , or of water vapor. Although the emission of excited OH radicals is closer to the visible emission of most useful phosphors than that of mercury, there still is a large difference.
  • the present invention provides a mercury-free EM radiation source emitting radiation in the wavelength range from about 254 nm to about 410 nm.
  • the radiation source emits in the wavelength range from about 300 nm to about 400 nm.
  • a light source comprises an EM radiation source emitting first EM radiation in the wavelength range from about 254 nm to about 410 nm, and at least a photoluminescent material excitable by the first EM radiation to emit a second EM radiation in the visible wavelength range.
  • visible light is generated by a method that comprises: (a) providing an EM radiation source emitting first EM radiation in the wavelength range from about 254 nm to about 410 nm; and (b) disposing at least a photoluminescent material that absorbs the first EM radiation and emits a second EM radiation in the visible wavelength range.
  • the present invention provides a mercury-free EM radiation source emitting radiation in the wavelength range from about 254 nm to about 410 nm.
  • the radiation source emits in the wavelength range from about 300 nm to about 400 nm.
  • the radiation source is a gas discharge containing materials that are capable of generating at least one of oxygen-, nitrogen-, and carbon-containing radicals.
  • these radicals are generated by bombarding materials containing oxygen, nitrogen, or carbon with charged species that may be generated by, for example, an electrical discharge or a high-frequency EM field.
  • the radicals in the discharge are in high-energy excited state, emitting EM radiation upon returning to a lower energy state.
  • Non-limiting examples of high-energy radicals that emit EM radiation in the range from about 254 nm to about 400 nm are OH, CO, CO + , CO 2 + , CN, CN + , NH, NO, N 2 O + , and C 2 . These radicals exhibit strong emission at the wavelength shown in Table 1, which also shows exemplary sources for the particular species.
  • a fluorescent lamp tube with associated electrodes was evacuated, and then filled with argon, nitrogen, and water vapor, each having an individual vapor pressure of about 2 torr (or 267 Pa), 0.2 torr (or 26.7 Pa), and 0.2 torr (or 26.7 Pa), respectively.
  • An electrical discharge was established in the tube, and emission spectra were obtained at time 0, 5, 7, 9, 25, 30, and 35 minutes after an electrical potential of 200 V was applied to the electrodes.
  • the emission spectra are shown in Figures 1-7. Strong emission is observed at wavelengths of about 306 nm and 336 nm, characteristic of emission from OH and NH radicals, respectively. Emission from these excited radicals continued well after the emission from high-energy argon had essentially stopped.
  • Mercury-free fluorescent lamps using at least one of the excited radicals disclosed above as the source of exciting radiation for photoluminescent materials (or phosphors) can improve the energy efficiency of fluorescent lamps because the wavelength of exciting radiation is closer to the phosphor emission wavelength (smaller Stokes shift) than the wavelength of mercury vapor discharge.
  • phosphors can be selected that strongly absorb exciting radiation from a particular high-energy radical, further increasing the lamp energy efficiency. Many such phosphors absorb strongly in the wavelength range from about 300 nm to about 410 nm, and thus have not been optimally used in conjunction with the mercury emission at 254 nm in conventional mercury discharge-based fluorescent lamps.
  • Non-limiting examples of such phosphors are (1) the blue emitting phosphors (Sr,Ca) 10 (PO 4 ) 6 Cl 2 :Eu 2+ ; Sr 2 P 2 O 7 :Eu 2+ ; (Sr,Mg) 2 P 2 O 7 :Eu 2+ ; and Ba 0.07 Mg 2 Al z O 3/2z+3 :Eu 0.13 2+ , where 14 ⁇ z ⁇ 25; (2) the green emitting phosphors 2SrO ⁇ 0.84P 2 O 5 ⁇ 0.16B 2 O 3 :Eu 2+ ; Sr 2 Si 3 O 8 ⁇ 2SrCl 2 :Eu 2+ ; Sr 4 Al 4 O 25 :Eu 2+ ; and Ba 0.8 Mg 1.93 Al 16 O 27 :EU 0.2 2+ , Mn 2 + ; (3) the green-yellow emitting phosphor Y 2 SiO 5 :Ce 3+ ,Tb 3+ ; and (4) the red emit
  • the construction of a mercury-free fluorescent lamp of the present invention is similar to that of a conventional fluorescent lamp.
  • Figure 8 schematically shows such a lamp.
  • An envelope 10 comprising an optically transparent material, such as glass, is provided with electrodes 20 and 30 comprising a material capable of emitting electrons, such as tungsten, and an end cap 25 at each end.
  • the term "optically transparent" in this disclosure means allowing at least 80 percent of light having wavelengths in the range from about 400 nm to about 800 nm to pass through a specimen having a thickness of 1 mm at an incident angle of less than 10 degrees.
  • Electrical leads 27 are connected to electrodes 20 and 30 to supply a voltage thereto.
  • the tungsten electrode is typically coated with a mixture of alkaline earth oxides to enhance electron emission.
  • a layer 50 of particles of at least a selected phosphor is deposited on the inner surface of the glass envelope to absorb the radiation emitted by the discharge.
  • a layer 40 of scattering particles can be deposited between the inner wall of glass envelope 10 and phosphor layer 50 to enhance light extraction.
  • Glass envelope 10 is evacuated and then charged with an inert gas, such as argon, at a pressure up to about 4000 Pa.
  • an inert gas such as argon
  • Other inert gases such as neon, krypton, and xenon, also may be used.
  • one or more gases that are capable of generating at least one of the radicals disclosed above when such gases are bombarded by charged species of the discharge are disposed in the glass tube at a pressure up to about 2 torr (or 267 Pa). The tube is sealed and is then ready for use.
  • the electrical discharge that provides charged species for generating excited mercury-free charged radicals of the present invention is generated by an induction coil at high frequency.
  • the coil generates a high-frequency magnetic field, which produces a magnetically induced plasma discharge.
  • Such a source of discharge has been put into practice in electrodeless discharge lamps.
  • One or more of the materials, which are listed in Table 1 above, that can generate excited radical species when bombarded by other species of the plasma, which excited radical species emit EM radiation in the UV range upon returning to a less excited state, can be used as a component of the filling gas in such electrodeless lamps to practice the present invention.
  • Frequencies in the range of greater than about 2 MHz, preferably greater than about 2.5 MHz, can be used to generate the magnetically induced plasma discharge.

Landscapes

  • Luminescent Compositions (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
EP05255050A 2004-08-17 2005-08-16 Gasentladung mit Emission im UV-A-Gebiet und Fluoreszenzlampe die diese Gasentladung enthält Withdrawn EP1659614A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
RU2004125185/09A RU2336592C2 (ru) 2004-08-17 2004-08-17 Газовые разряды, излучающие в ультрафиолетовом диапазоне, и люминесцентные лампы, содержащие такие газовые разряды
US11/077,567 US20060038496A1 (en) 2004-08-17 2005-03-11 Gas discharges having emission in UV-A range and fluorescent lamps incorporating same

Publications (2)

Publication Number Publication Date
EP1659614A2 true EP1659614A2 (de) 2006-05-24
EP1659614A3 EP1659614A3 (de) 2009-06-10

Family

ID=36087579

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05255050A Withdrawn EP1659614A3 (de) 2004-08-17 2005-08-16 Gasentladung mit Emission im UV-A-Gebiet und Fluoreszenzlampe die diese Gasentladung enthält

Country Status (1)

Country Link
EP (1) EP1659614A3 (de)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4262231A (en) 1978-10-25 1981-04-14 General Electric Company Helical wire coil in solenoidal lamp tip-off region wetted by alloy forming an amalgam with mercury
US5952791A (en) 1995-10-17 1999-09-14 International Business Machines Corporation Apparatus for detecting abnormal states in a discharge tube circuit and information processing system
US5959405A (en) 1996-11-08 1999-09-28 General Electric Company Electrodeless fluorescent lamp
US6040658A (en) 1995-08-01 2000-03-21 Aktsionernoe Obschestvo Zakkytogo Tipa Nauchno-Tekhniches Koe Agentstvo "Intellekt" Discharge lamp with HO radicals as radiating additives
US6051922A (en) 1994-03-25 2000-04-18 U.S. Philips Corporation Electrodeless low-pressure mercury vapour discharge lamp employing a high frequency magnetic field having a layer of aluminum oxide particles
US6137236A (en) 1997-12-03 2000-10-24 U.S. Philips Corporation Low-pressure discharge lamp and method of manufacturing a low-pressure discharge lamp

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002020745A (ja) * 2000-07-13 2002-01-23 Nec Kansai Ltd 弗化物蛍光体及びこれを使用した蛍光ランプ
GB0105492D0 (en) * 2001-03-06 2001-04-25 Univ Sheffield Discharge lamps using near-UV emitters

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4262231A (en) 1978-10-25 1981-04-14 General Electric Company Helical wire coil in solenoidal lamp tip-off region wetted by alloy forming an amalgam with mercury
US6051922A (en) 1994-03-25 2000-04-18 U.S. Philips Corporation Electrodeless low-pressure mercury vapour discharge lamp employing a high frequency magnetic field having a layer of aluminum oxide particles
US6040658A (en) 1995-08-01 2000-03-21 Aktsionernoe Obschestvo Zakkytogo Tipa Nauchno-Tekhniches Koe Agentstvo "Intellekt" Discharge lamp with HO radicals as radiating additives
US5952791A (en) 1995-10-17 1999-09-14 International Business Machines Corporation Apparatus for detecting abnormal states in a discharge tube circuit and information processing system
US5959405A (en) 1996-11-08 1999-09-28 General Electric Company Electrodeless fluorescent lamp
US6137236A (en) 1997-12-03 2000-10-24 U.S. Philips Corporation Low-pressure discharge lamp and method of manufacturing a low-pressure discharge lamp

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
R.W.B. PEARSE; A.G. GAYDON: "THE IDENTIFICATION OF MOLECULAR SPECTRA", 1976, CHAPMAN AND HALL

Also Published As

Publication number Publication date
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