EP0641510B1 - Lampe a decharge sans electrodes comportant un reseau d'adaptation d'impedance et de filtrage - Google Patents

Lampe a decharge sans electrodes comportant un reseau d'adaptation d'impedance et de filtrage Download PDF

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Publication number
EP0641510B1
EP0641510B1 EP93911322A EP93911322A EP0641510B1 EP 0641510 B1 EP0641510 B1 EP 0641510B1 EP 93911322 A EP93911322 A EP 93911322A EP 93911322 A EP93911322 A EP 93911322A EP 0641510 B1 EP0641510 B1 EP 0641510B1
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EP
European Patent Office
Prior art keywords
induction coil
electrodeless discharge
network
filter
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.)
Expired - Lifetime
Application number
EP93911322A
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German (de)
English (en)
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EP0641510A4 (fr
EP0641510A1 (fr
Inventor
Roger Siao
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Diablo Research Corp
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Diablo Research Corp
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Publication date
Priority claimed from US08/064,779 external-priority patent/US5541482A/en
Application filed by Diablo Research Corp filed Critical Diablo Research Corp
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Publication of EP0641510A4 publication Critical patent/EP0641510A4/fr
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    • 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

  • the embodiment described above may nonetheless produce unacceptable RFI levels owing to the close physical proximity of the components.
  • the power amplifier, the impedance matching and filter network and the induction coil share a common circuit ground, harmonic currents generated by the amplifier may circulate around the small grounding surface, which contains a finite impedance. As a result, a surface voltage potential develops along the grounding area. Since one end of the induction coil is either directly or capacitively connected to this circuit ground, it will act as a transmitting antenna and radiate a wide range of harmonics to free space.
  • Fig. 9 illustrates a cross-sectional view of the electronic components of an electrodeless discharge lamp positioned inside a metal chassis shield.
  • Figs. 12, 13 and 14 illustrate equivalent circuits useful in determining the voltages at the inputs to the induction coil in the embodiment of Fig. 11.
  • an electrodeless discharge lamp operates in essentially two stages, referred to respectively as the start-up and steady-state stages.
  • an electric field generated by the induction coil causes some of the atoms in the gaseous mixture to become ionized. As more and more electrons are freed in this process, a plasma of circulating charged particles is formed.
  • the lamp should turn on (i.e., the H-field ionization process should begin) at a specified DC voltage for a given magnetic flux across the induction coil.
  • the specified voltage should be as low as possible and is normally defined in terms of a required input power (P min ) to the series L-C induction network.
  • induction coil 14 When energized by an oscillating signal, induction coil 14 acts as an antenna and transmits electromagnetic radiation into the surrounding environment.
  • Amplifier 12 may be a Class D or Class E amplifier which delivers an output that may be rich in harmonics.
  • the basic frequency of the oscillator may be set at a frequency which is within a frequency band approved by the FCC, but the harmonics may be within bands that are forbidden for electrodeless discharge lamps. For example, electrodeless discharge lamps are frequently operated at 13.56 MHz, which is approved for industrial, scientific and medical (ISM) uses.
  • the second harmonic (27.12 MHz) and third harmonic (40.68 MHz) are also approved for ISM uses, but the fourth and fifth harmonics are fairly close to television channels 2 and 4, respectively.
  • the prohibited frequencies above the third harmonic must in particular be filtered to avoid radio frequency interference (RFI) problems, and RF radiation at the lower frequencies should also be minimized.
  • RFID radio frequency interference
  • Lamp turn-on occurs at 60 ⁇ V in ⁇ 100 volts DC.
  • the steady-state DC supply voltage is 130 volts and 19 RF watts is delivered to the induction coil network.
  • the attenuation must be 40 dB or more for f ⁇ 3f o where f o is the oscillator frequency which is equal to 13.56 MHz.
  • the induction coil is designed to have an inductance of 5.3 ⁇ H and an equivalent series resistance (ESR) of 2 ⁇ .
  • the lamp can be constructed to satisfy the FCC requirements as to permissible RFI emissions.
  • Inputs c and d of impedance matching and filter network 13 are directly connected to the single-ended output of amplifier 12, which may be rich in harmonics.
  • amplifier 12 may be rich in harmonics.
  • a Class D or Class E power amplifier may have an efficiency of 80% or higher but may have outputs which deviate substantially from a pure sine wave and are therefore very "noisy". Designing an effective filtering network for such an amplifier to fit into a very small space, such as is available in an electrodeless lamp, with adequate isolation between components, is very difficult.
  • Fig. 5 shows that if induction coil 14 is not Faraday-shielded, it will become a radio frequency transmitting antenna, which is fed by generators G o and G n . Even if the frequency of G o falls within an FCC-approved band (e.g., the band for ISM uses), the frequency of G n would contain the even and odd harmonics of the fundamental frequency. In order to meet the FCC limits, the harmonics produced by generator G n must be either eliminated or substantially reduced before they reach induction coil 14. According to this invention, a method is provided for separating, filtering and isolating generator G n . This is accomplished by connecting filters to all input and output terminals of amplifier 12 and oscillator 11, and by the addition of a conductive Faraday shield around these components.
  • FCC-approved band e.g., the band for ISM uses
  • symmetrical matching filters 13A and 13B converts the single-ended outputs e and f (circuit ground) of amplifier 12 into double-ended outputs which are identified in Fig. 6 as nodes g and h when referenced to virtual ground (the metal chassis 100). If the symmetrical matching filters 13A and 13B are exactly balanced (each corresponding component is a perfect match), the output signal of filters 13A and 13B will become signals equal in magnitude but opposite in phase at g and h, with respect to virtual ground. The difference between the signals at nodes g and h is equal to the magnitude of output signal of filter 13.
  • the embodiment described above provides excellent shielding of the harmonic frequencies produced by amplifier 12, and allows the components to be positioned adjacent each other in a closely confined space such as within an electrodeless discharge lamp. Unless further precautions are taken however, the fundamental frequency will still be radiated by induction coil 14. An arrangement for minimizing radiation of the fundamental frequency will now be described.
  • Point P in Fig. 10A represents a point well removed from coil 14 in relation to its length D.
  • ⁇ is the wavelength of the signal emitted by coil 14
  • X is the distance between point P and coil 14. With ⁇ >> D, and X >> D, point P sees coil 14 essentially as a point source.
  • Fig. 11 illustrates the portion of lamp 60 (Fig. 6) which includes amplifier 12 filters 13A and 13B and capacitors 16A and 16B.
  • induction coil 14 is shown as split into equal halves 14A and 14B inside an induction coil unit 120.
  • Resistors 121A and 121B together represent the reflected resistance from the induced plasma in the sealed vessel (not shown).
  • the point labelled z represents the physical center of coil 14.
  • Fig. 12 illustrates an equivalent circuit in which the voltage outputs at points g and h have been replaced by equivalent signal sources G a and G b which have impedances R a and R b , respectively.
  • the impedance of resistors R a and R b can be made much smaller than the impedances of capacitors 16A and 16B, inductors 14A and 14B, and resistors 121A and 121B. Therefore, the variation in the impedance of resistors R a and R b as a result of temperature changes and differences in the component values of filters 13A and 13B becomes insignificant to the balanced circuit network of Fig. 12 and can be ignored. Accordingly, the equivalent circuit of Fig.
  • the voltage at point s is of equal magnitude but opposite phase to the voltage at point t.
  • point z at the midpoint between coils 14A and 14B acts as a virtual ground, and the combination of coils 14A and 14B acts as a dipole antenna. If, as described above, the electrical length of coils 14A and 14B is small in relation to the wavelength of the RFI emitted by the "antenna", a point removed from coils 14A and 14B will not experience any net electrical field as a result of the radio frequency signal which is applied to coils 14A and 14B.
  • Fig. 14 illustrates the circuitry shown in Figs. 7 and 11, including in particular inductors L 3A and L 3B , capacitors 16A and 16B, inductors 14A and 14B, and resistors 121A and 121B.
  • symmetrical filter While a particular form of symmetrical filter is illustrated in Fig. 7, it will be understood by those skilled in the art that a wide variety of symmetrical filters can be designed, some containing, for example, Baluns transformers, conventional transformers, and frequency traps. The broad principles of this aspect of the invention are intended to cover all such variations.
  • amplifier illustrated in Figs. 4 and 6 is a single-ended Class D amplifier, other types of single-ended or double-ended (push-pull) amplifiers may be used to provide the input signal to the filter network of this invention.
  • oscillator 11 and amplifier 12 are supplied by a power supply 63, which preferably includes a power factor controller as described in the above mentioned Application Serial No. 07/886,718.
  • a line filter 62 is included.
  • Line filter 62 which is of a structure known to those skilled in the art, also protects the electronic components in lamp 60 against surges and other transients in the 60 Hz AC supply voltage.

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  • Circuit Arrangements For Discharge Lamps (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)

Claims (21)

  1. Lampe à décharge sans électrode (10) comprenant :
    un amplificateur haute fréquence (12) comportant deux bornes de sortie ;
    un réseau de bobine d'induction (14, 16) comportant deux bornes d'entrée ; et
    un réseau de filtre (13) connecté entre ledit amplificateur (12) et ledit réseau de bobine d'induction (14, 16),
       caractérisée en ce que :
    ledit réseau de filtre (13) comprend :
    un premier filtre (13A) et un second filtre (13B), ledit premier filtre (13A) comportant une première borne d'entrée connectée à une première borne de sortie (e) dudit amplificateur (12) et comportant une borne de sortie connectée à une première borne d'entrée (g) dudit réseau de bobine d'induction (14, 16), ledit second filtre (13B) comportant une première borne d'entrée connectée à une seconde borne de sortie (f) dudit amplificateur (12) et comportant une borne de sortie connectée à une seconde borne d'entrée (h) dudit réseau de bobine d'induction (14, 16), chacun desdits premier et second filtres (13A, 13B) comportant une seconde borne d'entrée, lesdites secondes bornes d'entrée des filtres étant jointes ensemble en un noeud commun (66), dans lequel lesdits premier et second filtres (13A, 13B) sont approximativement symétriques de telle sorte que les signaux de sortie des filtres (13A, 13B) soient sensiblement d'amplitudes égales et de phases opposées.
  2. Lampe à décharge sans électrode selon la revendication 1, comprenant un blindage conducteur pour ledit amplificateur (12), ledit noeud commun (66) étant couplé audit blindage conducteur.
  3. Lampe à décharge sans électrode selon la revendication 2, dans laquelle lesdits premier et second filtres (13A, 13B) et ledit amplificateur (12) sont refermés par ledit blindage et ledit réseau de bobine d'induction (14, 16) comprend une bobine d'induction (14), ladite bobine d'induction (14) étant positionnée à l'extérieur dudit blindage.
  4. Lampe à décharge sans électrode selon l'une quelconque des revendications 1 à 3, dans laquelle ledit réseau de bobine d'induction (14, 16) comprend un premier condensateur (16A) connecté entre ledit premier filtre (13A) et une/ladite bobine d'induction (14) et un second condensateur (16B) connecté entre ledit second filtre (13B) et ladite bobine d'induction (14).
  5. Lampe à décharge sans électrode selon la revendication 4, dans laquelle lesdits premier et second condensateurs (16A, 16B) sont sensiblement similaires.
  6. Lampe à décharge sans électrode selon l'une quelconque des revendications 1 à 5, dans laquelle ledit premier filtre (13A) comprend une première inductance (L1A) et une seconde inductance (L2A) et ledit second filtre (13B) comprend une troisième inductance (L1B) et une quatrième inductance (L2B), lesdites première et troisième inductances étant enroulées sur un premier noyau toroïdal commun et lesdites seconde et quatrième inductances étant enroulées sur un second noyau toroïdal commun.
  7. Lampe à décharge sans électrode selon la revendication 6, dans laquelle le couplage magnétique entre les première et troisième inductances (L1A, L1B) est inférieur à 0,4 et le couplage magnétique entre les seconde et quatrième inductances (L2A, L2B) est inférieur à 0,4.
  8. Lampe à décharge sans électrode selon la revendication 7, dans laquelle ledit premier filtre (13A) comprend des premier et second condensateurs (C1A, C2A) et ledit second filtre (13B) comprend des troisième et quatrième condensateurs (C1B, C2B), chacun desdits condensateurs étant joint audit noeud commun (66).
  9. Lampe à décharge sans électrode selon la revendication 2 et selon l'une quelconque des revendications 3 à 8 si elle dépend de la revendication 2, dans laquelle, pendant le fonctionnement de ladite lampe, ledit blindage et un point central (Z) de ladite bobine (14) sont maintenus à une masse de châssis (100).
  10. Lampe à décharge sans électrode selon la revendication 9, contenant deux condensateurs adaptés (16A, 16B), l'un (16A) desdits condensateurs étant connecté à une entrée (s) de ladite bobine (14) et l'autre (16B) desdits condensateurs étant connecté à l'autre entrée (t) de ladite bobine (14).
  11. Lampe à décharge sans électrode selon l'une quelconque des revendications 1 à 10, comprenant :
    une alimentation (63) ;
    un oscillateur haute fréquence (11) ;
    un amplificateur (12),
    ladite bobine d'induction (14) étant adaptée pour transmettre un signal haute fréquence délivré par ledit amplificateur (12) de manière à créer un plasma de particules chargées dans un gaz ;
    lesdits premier et second filtres (13A, 13B) étant connectés entre ledit amplificateur (12) et ladite bobine d'induction (14) de manière à inhiber le passage d'une interférence haute fréquence (RFI) sur ladite bobine d'induction (14) ; et
    un filtre supplémentaire (62) étant connecté entre ladite alimentation (63) et un contact d'alimentation (61) de ladite lampe de manière à inhiber le passage d'un signal de bruit sur ledit contact d'alimentation (61).
  12. Lampe à décharge sans électrode selon l'une quelconque des revendications 1 à 10, comprenant :
    un boítier en métal (100), ledit boítier en métal (100) renfermant ledit amplificateur haute fréquence (12), ladite bobine d'induction (14) étant positionnée à l'extérieur dudit boítier en métal (100), ledit boítier en métal (100) et le centre (Z) de ladite bobine (14) étant maintenus à une masse virtuelle.
  13. Lampe à décharge sans électrode selon l'une quelconque des revendications 1 à 12, dans laquelle ledit réseau de filtre (13) est adapté pour assurer une adaptation d'impédance, ladite adaptation d'impédance assurant deux transformations d'impédance présélectionnées pour ledit réseau de bobine d'induction (14, 16) dans des conditions de fonctionnement différentes de ladite lampe (10).
  14. Lampe à décharge sans électrode selon la revendication 13, dans laquelle l'une desdites conditions de fonctionnement se produit approximativement lorsque ladite lampe (10) est mise en marche et l'autre desdites conditions de fonctionnement est le fonctionnement en régime établi de ladite lampe (10).
  15. Lampe à décharge sans électrode selon la revendication 13 ou 14, dans laquelle ledit réseau d'adaptation d'impédance et de filtre (13) comprend un moyen de filtrage des harmoniques des signaux haute fréquence générés par ledit amplificateur (12) pour inhiber le passage desdits harmoniques sur ledit réseau de bobine d'induction (14, 16).
  16. Lampe à décharge sans électrode selon la revendication 14 ou 15, dans laquelle ledit réseau de bobine d'induction comprend une/la bobine d'induction (14) et en outre un récipient (15) contenant un gaz sélectionné, ladite bobine d'induction (14) fonctionnant pour créer un plasma de particules chargées dans ledit gaz après que ladite lampe (10) a été mise en marche ;
    dans laquelle ledit réseau de bobine d'induction (14, 16) présente une première impédance inhérente mesurée au niveau d'une paire de bornes d'entrée dudit réseau (14, 16) lorsque ladite lampe (10) est initialement mise en marche et une seconde impédance inhérente au niveau desdites bornes d'entrée lorsque ladite lampe (10) étant dans une condition de marche en régime établi ; et
    dans laquelle ledit réseau d'adaptation d'impédance et de filtre (13) est connecté audit réseau de bobine d'induction (14, 16), comporte une paire de bornes d'entrée et fonctionne pour transformer ladite première impédance inhérente selon une première impédance souhaitée mesurée au niveau de ses bornes d'entrée lorsque ladite lampe (10) est initialement mise en marche et pour transformer ladite seconde impédance inhérente selon une seconde impédance souhaitée mesurée au niveau de ses bornes d'entrée lorsque ladite lampe (10) est dans une condition de marche en régime établi.
  17. Lampe à décharge sans électrode selon la revendication 16, dans laquelle ladite seconde impédance inhérente est au égale à au moins dix fois ladite première impédance inhérente.
  18. Lampe à décharge sans électrode selon l'une quelconque des revendications 1 à 17, dans laquelle ledit réseau de filtre (13) comprend une pluralité de composants électriques et une masse, ladite masse présentant une impédance faible et lesdits composants étant isolés électriquement les uns des autres.
  19. Lampe à décharge sans électrode selon l'une quelconque des revendications 16 à 18, dans laquelle ledit récipient est un récipient scellé (15) qui contient un gaz ionisable, un plasma de particules chargées étant formé dans ledit récipient (15) lorsque ladite lampe (10) est en fonctionnement ; ladite bobine d'induction (14) étant positionnée à proximité dudit récipient scellé (15) sans une structure de blindage positionnée autour dudit plasma.
  20. Lampe à décharge sans électrode selon l'une quelconque des revendications 13 à 19, dans laquelle lesdites deux transformations d'impédance présélectionnées diffèrent d'un facteur d'au moins dix.
  21. Lampe à décharge sans électrode selon l'une quelconque des revendications 1 à 20, dans laquelle ledit amplificateur (12) est adapté pour générer un signal électrique qui présente une fréquence d'au moins 20 kHz, un filtre supplémentaire ou ledit filtre supplémentaire étant un filtre de ligne (62) connecté à une alimentation (63) de ladite lampe et à un contact d'alimentation (61) de ladite lampe de manière à inhiber le passage d'un signal de bruit sur ledit contact d'alimentation (61).
EP93911322A 1992-05-20 1993-05-20 Lampe a decharge sans electrodes comportant un reseau d'adaptation d'impedance et de filtrage Expired - Lifetime EP0641510B1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US88716692A 1992-05-20 1992-05-20
US887166 1992-05-20
US08/064,779 US5541482A (en) 1992-05-20 1993-05-19 Electrodeless discharge lamp including impedance matching and filter network
US64779 1993-05-19
PCT/US1993/004607 WO1993023975A1 (fr) 1992-05-20 1993-05-20 Lampe a decharge sans electrodes comportant un reseau d'adaptation d'impedance et de filtrage

Publications (3)

Publication Number Publication Date
EP0641510A1 EP0641510A1 (fr) 1995-03-08
EP0641510A4 EP0641510A4 (fr) 1995-05-17
EP0641510B1 true EP0641510B1 (fr) 1999-03-03

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP93911322A Expired - Lifetime EP0641510B1 (fr) 1992-05-20 1993-05-20 Lampe a decharge sans electrodes comportant un reseau d'adaptation d'impedance et de filtrage

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EP (1) EP0641510B1 (fr)
AU (1) AU4249893A (fr)
CA (1) CA2136086A1 (fr)
DE (1) DE69323742T2 (fr)
MX (1) MX9302912A (fr)
PH (1) PH29972A (fr)
WO (1) WO1993023975A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9407133D0 (en) * 1994-04-11 1994-06-01 Ge Lighting Ltd Emi suppression for an electrodeless discharge lamp
DE19734885C1 (de) * 1997-08-12 1999-03-11 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Verfahren zum Erzeugen von Impulsspannungsfolgen für den Betrieb von Entladungslampen und zugehörige Schaltungsanordnung
EP1198824A2 (fr) 1999-07-02 2002-04-24 Fusion Lighting, Inc. Lampe a rendement eleve et a forte brillance
EP1157592A1 (fr) * 1999-12-02 2001-11-28 Koninklijke Philips Electronics N.V. Systeme de lampe a induction et lampe a induction
US8487544B2 (en) * 2010-09-29 2013-07-16 Osram Sylvania Inc. Power splitter circuit for electrodeless lamp

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0221864A2 (fr) * 1985-11-05 1987-05-13 Lumalampan Aktiebolag Culot pour lampe à décharge électrique compacte
US5200672A (en) * 1991-11-14 1993-04-06 Gte Products Corporation Circuit containing symetrically-driven coil for energizing electrodeless lamp

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4383203A (en) * 1981-06-29 1983-05-10 Litek International Inc. Circuit means for efficiently driving an electrodeless discharge lamp
US4631449A (en) * 1984-08-06 1986-12-23 General Electric Company Integral crystal-controlled line-voltage ballast for compact RF fluorescent lamps
US4864194A (en) * 1987-05-25 1989-09-05 Matsushita Electric Works, Ltd. Electrodeless discharge lamp device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0221864A2 (fr) * 1985-11-05 1987-05-13 Lumalampan Aktiebolag Culot pour lampe à décharge électrique compacte
US5200672A (en) * 1991-11-14 1993-04-06 Gte Products Corporation Circuit containing symetrically-driven coil for energizing electrodeless lamp
WO1993010649A1 (fr) * 1991-11-14 1993-05-27 Gte Products Corporation Circuit contenant une bobine d'induction excitee symetriquement pour la mise sous tension d'une lampe a decharge sans electrodes

Also Published As

Publication number Publication date
WO1993023975A1 (fr) 1993-11-25
CA2136086A1 (fr) 1993-11-25
DE69323742T2 (de) 1999-07-01
MX9302912A (es) 1994-02-28
EP0641510A4 (fr) 1995-05-17
DE69323742D1 (de) 1999-04-08
AU4249893A (en) 1993-12-13
PH29972A (en) 1996-10-03
EP0641510A1 (fr) 1995-03-08

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