EP0702886A1 - Suppression des interferences electromagnetiques dans une lampe a decharge sans electrode - Google Patents

Suppression des interferences electromagnetiques dans une lampe a decharge sans electrode

Info

Publication number
EP0702886A1
EP0702886A1 EP95914457A EP95914457A EP0702886A1 EP 0702886 A1 EP0702886 A1 EP 0702886A1 EP 95914457 A EP95914457 A EP 95914457A EP 95914457 A EP95914457 A EP 95914457A EP 0702886 A1 EP0702886 A1 EP 0702886A1
Authority
EP
European Patent Office
Prior art keywords
excitation coil
signal
circuit arrangement
lamp
discharge 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Withdrawn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
EP95914457A
Other languages
German (de)
English (en)
Inventor
Ian Macdonald Green
Martin Christopher Steel
Francis Robert Trumble
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.)
GE Lighting Ltd
Original Assignee
GE Lighting Ltd
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 GE Lighting Ltd filed Critical GE Lighting Ltd
Publication of EP0702886A1 publication Critical patent/EP0702886A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/24—Circuit arrangements in which the lamp is fed by high frequency ac, or with separate oscillator frequency

Definitions

  • Electroless discharge fluorescent lamps are considered to be key elements in efforts to reduce energy demand stemming from the use of lighting products.
  • electrodeless discharge lamps offer significant energy efficiency advantages over a conventional incandescent lamp and further offer life expectance advantages even over the popular compact fluorescent lamps now being heavily promoted.
  • An example of an electrodeless fluorescent lamp can be found in US Patent No. 4,010,400 in which the basic principles of such lamp are described. This patent discusses that an ionizable medium can be contained in a lamp envelope and excited to a discharge state by the introduction of an RF signal in close proximity to the lamp envelope, which lamp envelope contains the appropriate phosphor coatings to allow the discharge energy to be converted to visible light.
  • a circuit arrangement for an electrodeless discharge lamp which circuit arrangement has EMI suppression features and which is effective for providing an RF signal which is inductively coupled to an ionizable medium contained in a lamp envelope portion of said electrodeless discharge lamp so as to excite such ionizable medium to a discharge state.
  • the electrodeless discharge lamp further includes a base portion in which is housed a drive circuit which is receptive of line power and is effective for converting such line power into a drive signal for driving the circuit arrangement to thus generate the RF signal.
  • the circuit arrangement of the present invention includes a core member which extends into a re-entrant cavity portion of the lamp envelope and has wound thereon, an excitation coil extending into the re-entrant cavity as well so as to be in close proximity to the ionizable medium.
  • a first tuning capacitor is series connected on one end to a first end of the excitation coil whereas a second tuning capacitor having the same capacitive value as the first tuning capacitor is series connected on one end to a second end of the excitation coil opposite to the first end.
  • Figure 1 is an elevational view in section of an electrodeless discharge lamp constructed in accordance with the present invention.
  • Figure 2 is a circuit diagram illustrating the theory behind the cause of conducted radio frequency interference in an electrodeless lamp.
  • Figure 3 is a circuit diagram of a prior art solution to the problem defined in fig. 2.
  • FIG. 4 is a circuit diagram of an EMI suppression arrangement constructed in accordance with the teachings of the present invention.
  • a low pressure electrodeless fluorescent lamp 10 includes a lamp envelope 12 having a lower portion which fits within a housing base assembly 17.
  • a conventional threaded screw base 19 is mounted on the housing base assembly 17 for connecting line power to a ballast circuit arrangement 24 disposed within housing base arrangement 17.
  • the ballast circuit arrangement 24 includes an RF coil portion 16 which extends within a re-entrant cavity portion 15 of the lamp envelope 12.
  • the RF coil portion includes a core and a winding portion which are disposed around the exhaust tube 14 extending down from the top of the re-entrant cavity 15 and into the region of the base housing assembly 17 in which the ballast circuit arrangement 24 is disposed.
  • the ballast circuit arrangement 24 When energized, the ballast circuit arrangement 24 is effective for generating an RF signal which is inductively coupled to a fill contained within lamp envelope 12 so as to produce discharge 23.
  • Discharge 23 is effective in a conventional manner for converting energy into visible light in cooperation with the fluorescent coating 20 disposed on the interior wall surface of lamp envelope 12.
  • the capacitive reactance, -jX can result in excessive interference if Z and -jX have similar magnitudes.
  • the conductive current (i) through excitation coil 16' and the displacement current to ground (i g ) are also indicated in fig. 2.
  • the effect of stray capacitive current has been neglected since for practical coils, the former is significantly less than the latter.
  • V1 can be expressed as:
  • V1 is also the voltage across loaded coil 16' whose impedance is Z; thus:
  • an embodiment of the present invention presents a solution to the RFI problem without incurring the additional costs and complexity of the circuit of fig. 3.
  • tuning capacitors 26 and 27, having the same capacitance value (-jX/2) are connected to the respective ends of excitation coil 16. Since one end of excitation coil 16 is no longer grounded as in the circuit of fig. 2, the two displacement paths shown in dotted lines in fig. 4 must be added together to give the total leakage current. Despite splitting the original single tuning capacitor 21, the present circuit remains electrically the same except for the additional stray capacitance.
  • Equation 7 can be simplified to:

Abstract

Montage de circuit pour lampe fluorescente sans électrode permettant de supprimer les interférences électromagnétiques et destiné à produire un signal HF d'excitation du contenu d'une envelope (12) de la lampe sans électrode. Le montage de circuit comprend un circuit de protection (24) pouvant être alimenté par le secteur et destiné à convertir l'alimentation du secteur en un signal HF permettant de provoquer la décharge (23) à l'intérieur de l'enveloppe (12). Le circuit de protection (24) comprend une bobine d'excitation (16) traversant une cavité rentrante (15) formée dans l'enveloppe (12). Un premier condensateur d'accord (26) est connecté par l'une de ses bornes à une première extrémité de la bobine d'excitation tandis qu'un deuxième condensateur d'accord (27) est connecté par l'une de ses bornes à l'autre extrémité de la bobine d'excitation (16), les valeurs capacitives du premier condensateur d'accord et du second condensateur d'accord étant sensiblement les mêmes. Le montage capacitif séparé coopère avec la bobine d'excitation pour produire un signal HF et permet de réduire les interférences électromagnétiques qui pourraient être émises par une charge non équilibrée à travers la bobine d'excitation.
EP95914457A 1994-04-11 1995-04-06 Suppression des interferences electromagnetiques dans une lampe a decharge sans electrode Withdrawn EP0702886A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB9407133 1994-04-11
GB9407133A GB9407133D0 (en) 1994-04-11 1994-04-11 Emi suppression for an electrodeless discharge lamp
PCT/GB1995/000798 WO1995028070A1 (fr) 1994-04-11 1995-04-06 Suppression des interferences electromagnetiques dans une lampe a decharge sans electrode

Publications (1)

Publication Number Publication Date
EP0702886A1 true EP0702886A1 (fr) 1996-03-27

Family

ID=10753344

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95914457A Withdrawn EP0702886A1 (fr) 1994-04-11 1995-04-06 Suppression des interferences electromagnetiques dans une lampe a decharge sans electrode

Country Status (5)

Country Link
EP (1) EP0702886A1 (fr)
JP (1) JPH08511651A (fr)
CA (1) CA2164710A1 (fr)
GB (1) GB9407133D0 (fr)
WO (1) WO1995028070A1 (fr)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
PH29972A (en) * 1992-05-20 1996-10-03 Diablo Res Corp Electrodeless discharge lamp including impedance matching and filter network
CA2137289A1 (fr) * 1992-06-05 1993-12-23 Derek Bray Lampe a decharge sans electrode comportant un amplificateur classe e symetrique et une bobine bifilaire

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9528070A1 *

Also Published As

Publication number Publication date
GB9407133D0 (en) 1994-06-01
JPH08511651A (ja) 1996-12-03
WO1995028070A1 (fr) 1995-10-19
CA2164710A1 (fr) 1995-10-19

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