WO2001039555A1 - Lampes sans electrode autoreglables - Google Patents

Lampes sans electrode autoreglables Download PDF

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Publication number
WO2001039555A1
WO2001039555A1 PCT/US2000/030154 US0030154W WO0139555A1 WO 2001039555 A1 WO2001039555 A1 WO 2001039555A1 US 0030154 W US0030154 W US 0030154W WO 0139555 A1 WO0139555 A1 WO 0139555A1
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WO
WIPO (PCT)
Prior art keywords
oscillator
amplifier
circuit
feedback
lamp
Prior art date
Application number
PCT/US2000/030154
Other languages
English (en)
Inventor
Donald A. Maclennan
Douglas A. Kirkpatrick
Peter Tsai
James T. Dolan
Yongzhang Leng
Paul Finch
John J. Nagel
Bruce H. Harkness
George W. Raffoul
Richard Liu
Original Assignee
Fusion Lighting, Inc.
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 Fusion Lighting, Inc. filed Critical Fusion Lighting, Inc.
Priority to JP2001540569A priority Critical patent/JP2003515875A/ja
Priority to AU15809/01A priority patent/AU1580901A/en
Priority to DE10085223T priority patent/DE10085223T1/de
Publication of WO2001039555A1 publication Critical patent/WO2001039555A1/fr

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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
    • 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
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/2806—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices and specially adapted for lamps without electrodes in the vessel, e.g. surface discharge lamps, electrodeless discharge lamps
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Definitions

  • the present invention pertains to the operation of oscillator-driven loads which have changing resonant frequency, an example of which is an electrodeless lamp.
  • a radio frequency (RF)-driven load may have changing characteristics which affect the resonant frequency.
  • the resonant frequency may vary considerably through a start up phase of operation of the load.
  • the resonant frequency of the load changes in the post-start up phases of operation.
  • Examples of such RF- driven loads include radio frequency antennae.
  • oscillators have been employed in connection with RF-driven loads operating in certain low power, low frequency environments. Such known types of oscillators include the Colpitts (Clapp) oscillator, the Hartley oscillator, and the Armstrong oscillator. These known types of oscillators were employed years ago, primarily for transmitters. See, e.g., Mandl, Electronics Handbook, Reston Publishing Company, Inc., 1983, pages 73 - 77.
  • An electrodeless lamp is an example of an RF-driven load which, by contrast, utilizes high power and high frequencies. Some electrodeless lamps are capable of generating high brightness levels over more than 10,000 hours of operation without requiring replacement. Electrodeless lamps have no internal electrodes, but rather rely upon external structures to achieve breakdown and excitation of a fill material for emission of light. Typically electrodeless lamps are classified as inductively coupled (H discharge), capacitance coupled (E discharge), microwave discharge, and traveling wave discharge. Certain basic principles of electrodeless lamps, as well as each of these classifications, are discussed in the literature. See, e.g., Wharmby, D.O., "Electrodeless Lamps For Lighting: A Review", IEEE Proceedings- A, Vol. 140, No. 6, November 1993, pp.
  • An inductively coupled electrodeless lamp can be analogized to an electrical transformer.
  • the fill material e.g., plasma
  • a discharge vessel serves as a single turn secondary coil
  • a primary (exciter) coil is connected via suitable impedance matching to a power source.
  • the primary (exciter) coil can be outside the discharge vessel; inside the vessel; within a reentrant; or wrapped around part of the tubular lamp forming a torus.
  • the magnetic field can be provided by a coil with an air core, or a magnetic core.
  • an alternating current in the coil causes a changing magnetic field, which induces an electric field which drives a current in the plasma.
  • Certain electrical properties and phenomena involved with inductively coupled electrodeless lamps have been documented, e.g., by Piejak, R.B. et al., "A Simple Analysis of An Inductive RF Discharge", Plasma Sources Sci. Technlol. 1 (1992), pages 179 - 186. Examples of structures and operating techniques for inductively coupled electrodeless lamps are provided in PCT Publication No.
  • the plasma-filled bulb comprises the RF-driven load.
  • the cold plasma After start up and until ignited, the cold plasma has an infinite impedance, with the power supply (oscillator) seeing a nearly reactive load.
  • the resistance and inductance of the bulb's plasma significantly and continuously changes, thereby changing the resonant frequency of the lamp head. Since the resistance and inductance of the plasma are reflected back into the primary or driving circuit, both the frequency and Q of the driving circuit are affected. Typically this means that special frequency adjusting circuitry is required to minimize the effect of the changing resonant frequencies attributable to startup, operation, and aging. Otherwise, lamp-out or high reflected power due to poor matching can occur.
  • a RF source provides RF energy at a certain frequency to a lamp head, the lamp head being part of a separate resonant circuit which is designed to resonate at the frequency of the provided energy.
  • both frequency matching (tuning) and impedance matching are important for optimizing overall system efficiency.
  • PCT Publication No. WO 99/36940 describes, e.g., lamp systems of this type with a novel RF source which can efficiently provide RF power at high power (e.g., 70 watts or more) at frequencies above 300 MHz (e.g., 700 - 900 MHz) to the lamp head resonant circuit.
  • electrodeless lamps which employ separate RF source and control circuits include additional components and circuitry for, among other things, frequency tuning, with associated manufacturing costs and complexity.
  • Electrodeless lamps are configured with the lamp being part of the RF source, e.g., part of a tank circuit of an oscillator, so that the lamp influences, at least in part, the operating frequency of the oscillator circuit.
  • the lamp can be either inductively coupled or capacitively coupled.
  • Respective examples of these coupling techniques are disclosed in United States Patent 4,010,400 to Hollister and United States Patent 4,485,333 to Goldberg.
  • Self-tuning oscillator circuits presuming the conditions for oscillation are met) are taught, but in the context of low frequency applications.
  • the effective integration of the load e.g., the lamp head
  • impedance matching is important to optimizing overall system efficiency.
  • a self-tuned system includes a gain element (active element) together with an RF-driven load configured as an oscillator which uses the RF-driven load as a frequency determining element for the system.
  • the gain element comprises, for example, an amplifier which may be single stage, dual stage, or other configuration.
  • the oscillator-driven load is a lamp head circuit for an electrodeless lamp.
  • the lamp head circuit of the electrodeless lamp comprises an excitation coil proximate an envelope enclosing a fill, the fill forming a plasma discharge when ignited.
  • the lamp head circuit includes a high power capacitance and a matching capacitance.
  • Various oscillator configurations can be used with the load, including modified Hartley, modified Colpitts (Clapp), and modified Armstrong configurations.
  • the oscillator comprises a feedback system connected between the oscillator-driven load and the amplifier.
  • various embodiments of clamping circuits can also be utilized to limit a feedback signal applied by the feedback system to a region tolerated by the amplifier, as well as various locations for the clamping circuits.
  • the feedback system comprises plural segments having different impedances, with the clamping circuit being connected to one of the plural segments which has an impedance that overcomes limitations of an element of the clamping circuit (e.g., high dynamic impedance of a Shottky diode comprising the clamping circuit).
  • the feedback system is, in one embodiment, a dual path feedback system.
  • the self-tuned systems of the invention operate at high frequency and high power.
  • various inventive techniques are disclosed for, e.g., providing sufficient gain and for enhancing ignition/self-starting (e.g., reducing start time).
  • Techniques and arrangements for ensuring sufficient gain for the self-tuned systems of the invention include choice of oscillator configuration, multi-stage amplification (when required), and feedback system configuration. For example, a Hartley oscillator configuration is preferred over a Colpitts oscillator configuration when the active element is a low gain device for maintaining oscillation at a high frequency while transferring significant power to bulbs of self-tuned lamps. Further, an additional stage(s) of amplification can be added. Moreover, a feedback system with dual feedback delay lines promotes greater gain.
  • the present invention also addresses improved ignition/reduced start times for the loads of self-tuned systems.
  • Self-ignition can be achieved in numerous ways, such as (for example) using a low pressure rare gas fill for the lamp bulb.
  • Another technique is to increase current in the excitation coil.
  • a self- tuned system can include both a starting oscillator and a power oscillator, with the starting oscillator having an impedance/operating frequency matched/tuned to the cold tank. After the self-tuned system starts, the impedance of the tank has a better match to the power oscillator. The start oscillator is turned off when it is sensed that the power oscillator has started to draw high power.
  • Fig. 1 is a schematic view of a resonant system including an oscillator and an oscillator-driven load.
  • Fig. 2 is a schematic view of a lamp head circuit for an inductively coupled electrodeless lamp.
  • Fig. 3 is a schematic view of a lamp head circuit for a capacitively coupled electrodeless lamp.
  • Fig. 4 is a diagrammatic depiction of a partial cross-section of a lamp head for the inductively coupled electrodeless lamp of Fig. 2.
  • Fig. 5 - Fig. 7 are schematic views of resonant circuits which employ differing oscillators for driving an electrodeless lamp head circuit as a load.
  • Fig. 8 - Fig. 10 are schematic views of resonant circuits which correspond to the circuits of Fig. 5 - Fig. 7, but wherein two stage amplification is provided in the differing oscillators.
  • Fig. 11 , Fig. 12, and Fig. 13 are schematic views of clamping circuits according to differing embodiments the present invention.
  • Fig. 14, Fig. 15, and Fig. 16 show cross-sectional views of example differing coil configurations with which the invention can be used.
  • Fig. 17 is a cross-sectional view showing a coil with integral tap for use in a modified Hartley oscillator included in a resonant system of the invention.
  • Fig. 18 is a schematic view of a circuit layout for one example implementation of a resonant system utilizing a modified Hartley type oscillator in conjunction with a electrodeless lamp head circuit.
  • Fig. 19 is a partial cross section representation of the oscillator taken along line 19-19 of Fig. 18.
  • Fig. 20 is a schematic view showing a first location for connecting a clamping circuit to the circuit layout of Fig. 18.
  • Fig. 21 is a schematic view showing a second location for connecting a clamping circuit to the circuit layout of Fig. 18.
  • Fig. 22 and Fig. 23 are schematic views of yet other resonant circuit variations in accordance with the present invention.
  • Fig. 24 is a schematic view of a self-tuned system that includes both a power oscillator and a starting oscillator
  • Fig. 25, Fig. 26, Fig. 27, and Fig. 28 are schematic views showing equivalent circuits for various Colpitts-type oscillator variations.
  • Fig. 29 is a schematic view showing equivalent circuits for an Armstrong-type oscillator variation.
  • Fig. 1 shows a self-tuning system which includes a generic oscillator 30 which drives a load 32.
  • the load 32 is of a type which provides a reflection to oscillator 30.
  • the oscillator 30 includes an amplifier 34 having an amplification factor A and a feedback delay or matching element 36 having a feedback factor B (the feedback factor B being phase change or delay adjustment as well as matching and attenuation).
  • the load 32 provides a reflection at the amplifier plane. In the self- tuning system of Fig. 1 feedback comes from load 32 (as indicated by the dashed line) rather than directly from the oscillator output.
  • a load which can be used in a self-turning system such as that of Fig. 1 is an electrodeless lamp.
  • electrodeless lamps can fall into various classifications.
  • Fig. 2 depicts basic aspects of a lamp head circuit for an inductively coupled (H discharge) electrodeless lamp.
  • Fig. 3 depicts basic aspects of a lamp head circuit for a capacitance coupled (E discharge) electrodeless lamp.
  • H discharge inductively coupled
  • E discharge capacitance coupled
  • the representative illustration of the lamp head circuit of an inductively coupled (H discharge) electrodeless lamp as shown in Fig. 2 includes an excitation coil 40 situated proximate an envelope or bulb 42 enclosing a fill 44.
  • the lamp head circuit of the inductively coupled electrodeless lamp of Fig. 2 includes a high power capacitance C1 connected to a first end of the excitation coil 40 and a matching capacitance C2 connected to a second end of excitation coil 40 and to electrical ground.
  • RF input 43 is applied to the lamp head circuit at a point between the high power capacitance C1 and the matching capacitance C2.
  • the inductively coupled electrodeless lamp of Fig. 2 operates at an elevated frequency in the range of 100 to 3000+ MHz.
  • the fill 44 forms a plasma discharge 46, thereby providing illumination.
  • Fig. 4 being a cross-sectional view of Fig. 2, shows plasma discharge 46 as having an essentially toroidal or annular shape.
  • the excitation coil 40 has an inductance and resistance. Once ignited the plasma has a respective inductance and resistance.
  • Fig. 5 - Fig. 7 illustrate three example embodiments showing how, in accordance with the present invention, the lamp head circuit of an electrodeless lamp is incorporated as load 32 into the self-tuning circuit of Fig. 1.
  • the illustrations of Fig. 5 - Fig. 7 particularly show an inductively coupled lamp as being representative of electrodeless lamps generally (including, e.g., electrodeless lamps of other classifications).
  • elements in Fig. 5 - Fig. 7 which are comparable to those in Fig. 1 and Fig. 2 have comparable numerical identifiers, alphabetical suffixes A, B, and C are provided in order to distinguish the elements as belonging to Fig. 5, Fig. 6, or Fig. 7, respectively.
  • Fig. 5 particularly shows oscillator 30A, which drives the lamp head circuit of the electrodeless lamp, taking the form of a modified Hartley oscillator.
  • the oscillator 30A includes amplifier 34A which has an input terminal and an output terminal. The output terminal of amplifier 34A is connected between high power capacitance C1 and matching capacitance C2. A tap 60 is connected to the excitation coil 40. Feedback element 36A and blocking capacitance 62 are connected in series between tap 60 and the input terminal of amplifier 34A.
  • the modified Hartley oscillator of Fig. 5 thus has a grounded source and grounded excitation coil 40.
  • B represents various tuning adjustments that are made including the length of the coil tap inductance.
  • the oscillator 30A of Fig. 5 provides high feedback, which is beneficial for relatively lower gain single transistor amplifiers.
  • Fig. 8 shows a modification, particularly oscillator 130A, which employs two stage amplifier 134A.
  • Fig. 6 shows oscillator 30B taking the form of a modified Colpitts (Clapp) oscillator.
  • the oscillator 30B includes amplifier 34B.
  • Amplifier 34B has an input terminal and an output terminal, the output terminal of the amplifier being connected between high power capacitance C1 and matching capacitance C2.
  • a third capacitance C3 is connected between matching capacitance C2 and ground.
  • Feedback element 36B has a first end connected between matching capacitance C2 and third capacitance C3, and a second end connected to the input terminal of amplifier 34B.
  • a significant difference between oscillator 30B of Fig. 5 and oscillator 30A of Fig. 6 is that oscillator 30B has less feedback.
  • a two stage amplifier version of the modified Colpitts (Clapp) oscillator embodiment shown as oscillator 130B in Fig. 9 with two stage amplifier 134B, is preferred in view, e.g., of the feedback parameters.
  • Fig. 7 shows oscillator 30C taking the form of a modified Armstrong oscillator.
  • the oscillator 30C includes amplifier 34C.
  • Amplifier 34C has an input terminal and an output terminal, the output terminal of the amplifier being connected between high power capacitance C1 and matching capacitance C2.
  • oscillator 30C features a pick-up coil 64 arranged co-axially to excitation coil 40.
  • Pick-up coil 64 has a first end and a second end, the first end of pick-up coil 64 being connected to electrical ground.
  • Feedback element 36C is connected between the second end of pick-up coil 64 and the input terminal of amplifier 34C.
  • the modified Armstrong oscillator 30C of Fig. 7 obtains its feedback signal from pick-up coil 64.
  • Fig. 10 shows an embodiment wherein the modified Armstrong oscillator 130C includes two stage amplifier 134C.
  • the self-tuning RF oscillator for an oscillator-driven lamp head circuit follows the frequency requirements of the lamp head circuit by taking its input signal from the lamp head circuit.
  • the modified Hartley (Fig. 5, 8), Colpitts (Fig. 6, 9), and Armstrong (Fig. 7, 10) oscillators are example oscillators which can be employed to fulfill this function.
  • Fig. 11 , Fig. 12, and Fig. 13 respectively show first, second, and third embodiments of clamping circuits 100A, 100B, 100C that can be utilized with embodiments of the invention for voltage protection.
  • the clamping circuits 100A, 100B, 100C limit the feedback signal of an oscillator 30 of the invention to a region tolerated by the active element(s) of the oscillator 30, e.g., amplifier 34. Such being the case, the clamping circuits 100A, 100B, 100C are connected either directly or via a feedback system to a gate of amplifier 34. In general terms, the clamping circuits should provide high current carrying capability, present low capacitance and inductance, and utilize short line lengths. In the ensuing discussion, general reference to clamping circuit 100 can refer to either clamping circuit 100A of Fig. 1 1 , clamping circuit 100B of Fig. 12, clamping circuit 100C of Fig. 13, or to equivalents or variations thereof.
  • clamping circuit 100A comprises a series pair of switching diodes, e.g., Shottky diodes 102 and 104, with the anode of Shottky diode 104 and the cathode of Shottky diode 102 being connected to fixed voltages, -V B and +V B , which should not exceed the maximum rated voltage for the active device and are typically 70 - 80% of such rating.
  • the 12 also has switching diodes (e.g., Shottky diodes 102, 104), but further has a regulating diode (e.g., Zener diodes 106, 108) connected between each Shottky diode 102, 104 and ground.
  • a regulating diode e.g., Zener diodes 106, 108
  • the anode of Zener diode 108 is connected to the anode of Shottky diode 104, with the cathode of Zener diode 108 being connected to ground.
  • the cathode of Zener diode 106 is connected to the cathode of Shottky diode 102, with the anode of Zener diode 106 being connected to ground.
  • the Shottky diodes 102, 104 can be a series pair MA4CS102B (with a max C, of 1.0 pF); the Zener diodes 106, 108 can be 16 volt TVS/Zener IN6276, for example.
  • the clamping circuit 100C of Fig. 13 differs from that of Fig. 12 in having a small capacitance connected in parallel with each of Zener diodes 106, 108.
  • the coils of an electrodeless lamp can take a variety of configurations.
  • Fig. 14, Fig. 15, and Fig. 16 show three examples of coil cross-sectional configurations.
  • Fig. 14 shows what has been termed an "Omega" coil 140 with leads bent tangential to the coil loop;
  • Fig. 16 shows a "DCC" coil with leads extending approximately radially from the coil;
  • Fig. 15 shows a modified coil with one tangential lead and one radial lead.
  • the present invention can be used with any type of coil including those illustrated.
  • a modified Hartley oscillator such as that shown in Fig. 5 or Fig.
  • the tap 60 be located at a proper position on and formed integral with the excitation coil 40. Positioning the junction of the tap 60 to the excitation coil 40 can be selected to increase current in the excitation coil, thereby assisting with self-ignition of the electrodeless lamp.
  • the modified Hartley oscillator involves connection of the feedback system to the excitation coil via the tap (see, e.g., tap 60 in Fig. 5).
  • the tap is embedded or connected to the excitation coil in one assembly, e.g., there being no welded or soldered connections of the tap to the excitation coil.
  • the excitation coil and tap can be formed from one solid piece (e.g., of copper).
  • the tap can be stamped and formed to the excitation coil, or the entire assembly formed by casting.
  • Fig. 17 shows one such coil formed with the tap being integral.
  • the feedback voltage increases as the angle ⁇ of the tap with respect to the ground lead increases and coil losses also increase as the angle ⁇ increases. If the angle is too large, a high feedback signal is obtained but the losses may be too great to sustain a discharge.
  • the tap preferably positioned at an angle which provides sufficient feedback voltage while minimizing the corresponding losses. Higher angles may be required for low gain devices.
  • the tap 60 is positioned about 15-30% around the single turn of excitation coil 40 relative to the ground lead in order to facilitate sufficient feedback through the tap while maintaining satisfactory current through the excitation coil.
  • Fig. 18 shows a circuit board layout for one example implementation of a self- tuning system utilizing a modified Hartley type oscillator 230.
  • Fig. 19 is a partial cross section representation of the oscillator 230 taken along line 19-19 of Fig. 18.
  • Fig. 18 and Fig. 19 show excitation coil 240 having a first end connected (soldered) to a ground pad 280.
  • a second end of excitation coil 240 is connected via high power capacitance C1 and a transmission line 281 (approximately 10 ohm) to a drain 282 of amplifier 234.
  • the tap 260 of oscillator 230 extends from excitation coil 240 to blocking capacitance 262.
  • the blocking capacitance 262 is situated on a feedback pad 284 which connects to a dual feedback system comprising feedback system 286A and feedback system 286B.
  • the feedback system 286A and feedback system 286B are essentially identical mirror images of one another, each comprising various segments including a 15 ohm transmission line segment 288A,B; a 93 ohm transmission line segment 290A.B; an adjustable capacitance 292A.B; and a 24 ohm transmission line segment 294A.B.
  • the transmission line segment 294A.B connects to the gate 283 of amplifier 234. In the oscillator 230 of Fig.
  • the 93 ohm transmission line segments 290A.B are of narrower width than the other transmission lines constituting the feedback systems 286A.B to give good electrical length (to get the correct phase).
  • the adjustable capacitances 292A.B are approximately between 1 pF and 3 pF.
  • the amplifier 234 can be, for example, Motorola part MRF184 or MRF373.
  • the feedback system 286A.B with its dual feedback delay line thus incorporates a section (93 ohm transmission line segment 290A.B) of higher impedance for delay adjustment, and a short low impedance section ( transmission line 281) from the transistor drain to the high voltage capacitor for coil-transistor separation.
  • a section 93 ohm transmission line segment 290A.B
  • a short low impedance section transmission line 281 from the transistor drain to the high voltage capacitor for coil-transistor separation.
  • the duality aspect of feedback system 286A,B provides both stability and robustness.
  • clamping circuits 100 of the present invention can be connected on the gate of the amplifier 34 of the oscillators 30 of the present invention, it is preferred to locate the clamping circuits 100 on a part of the feedback system with a higher impedance.
  • gate 283 may be 2 to 3 ohms or even 0.3 to 1 ohm (e.g., for a Motorola MRF-184 amplifier in the range of 700 to 1000 MHz)
  • the feedback transmission line segments 288, 290, and 294 have impedances of 15, 93, and 24 ohms, respectively.
  • Fig. 20 thus shows how the clamping circuit 100 (which, as mentioned above, can be, e.g., either clamping circuit 100A of Fig.
  • clamping circuit 100B of Fig. 12, or clamping circuit 100C of Fig. 13 can be connected to the 93 ohm transmission line segment 290A, B of feedback system 286A.B.
  • Fig. 21 shows how the clamping circuit 100 can be connected to 24 ohm transmission line segment 294A.B.
  • the clamping circuit 100 is connected to a point on the feedback system 286 at which the high dynamic impedance (approximately 5 ohms) of the Shottky diodes 102, 104 do not present a problem (e.g., the 93 ohm transmission line segment 290 in Fig. 20 and the 24 ohm transmission line segment 294 in Fig. 21).
  • Fig. 22 shows a modified Hartley-type oscillator variation 330 for bulb 342.
  • the excitation coil 340 has a tap 360 formed therewith, which is connected via blocking capacitance 362 to a gate of amplifier 334.
  • a clamping circuit 100B is also connected to the gate of amplifier 334, the clamping circuit 100B being essentially the same as that illustrated in Fig. 12.
  • Element 390 shown in Fig. 22 is an RF choke (RFC), having 5 turns, 20 AWG, inner diameter of 0.126 inch.
  • RFC RF choke
  • Fig. 23 shows yet another self-tuning circuit variation.
  • the excitation coil 440 is in proximity to bulb 442, and is connected via the high power capacitance C1 (on the order of about 6pF) to the output of amplifier 434.
  • the capacitances 494 and 495 have values between about 20 and 40 pF; capacitance 496 is large enough to handle feedback.
  • a driving current i 1 is shown.
  • a clamping circuit 100A (similar to that shown in Fig. 1 1) can be connected to the gate of amplifier 434.
  • the amplifier 434 must have sufficient gain, and may include plural stages, if necessary. However, the size must be small to preclude phase change around the loop.
  • aspects of the invention also provide various arrangements and techniques for providing sufficient gain for the self-tuned lamps of the invention.
  • a Hartley oscillator configuration (such as that shown in Fig. 5 or Fig. 18) is preferred over a Colpitts oscillator configuration when the active element is a low gain device in view, e.g., of the fact that the Hartley oscillator configuration requires less feedback.
  • a feedback system (such as feedback system 486 in Fig. 18) with dual feedback delay lines promotes greater gain.
  • an additional stage(s) of amplification can be added.
  • oscillators such as those shown in Fig. 5, Fig. 6, and Fig. 7 can have single stage amplification
  • a second stage amplification can also be added (as shown in Fig. 8 - Fig. 10, respectively) in order to boost the loop gain.
  • the feedback signal can be clamped to a region tolerated by the active element(s).
  • a self-tuned system can include both a power oscillator 501 and a starting oscillator 502, both connected to a tank circuit 503 of a self-tuned system such as a self-tuned lamp. Feedback 508 from tank circuit 503 is applied to power oscillator 501. Power is applied via power sense circuit 504 both to power oscillator 501 and starting oscillator 502.
  • Starting oscillator 502 has a high impedance Z out1 (on output 506) matched to the tank circuit 503 when tank circuit 503 is cold and an operating frequency tuned to tank circuit 503 when tank circuit 503 is cold.
  • Z, n on input 507 of the tank circuit 503 is pulled down so that it has a better match to power oscillator 501.
  • Power sense circuit 504 turns off the starting oscillator 502 when power oscillator 501 starts drawing high power.
  • Z out2 (on output 505) is approximately equal to Z ⁇ n when the tank circuit 503 is hot and Z out2 is much less than Z, n when the tank circuit 503 is cold.
  • the bulb 42 may be formed of any suitable material, such as quartz, sapphire, or polycrystalline alumina (for example). While the bulb 42 has a spherical shape in the illustrated embodiments, other shapes for bulb 42 are possible, such as cylindrically shaped and pill-box shaped bulbs, for example.
  • the bulb 42 can be an aperture bulb. An aperture bulb is surrounded with a reflecting ceramic jacket, except in a region of an aperture through which light is emitted.
  • the amount of quartz or other material utilized for the bulb 42 is as small as possible.
  • An electrodeless lamp bulb must reach a temperature such that the coldest part of the lamp quartz envelope is sufficiently hot so as to provide a vapor fill of correct density.
  • the inventors have performed calculations and experiments pertaining to heat capacity of the quartz bulb, the results of which are shown in Table 1 - Table 4.
  • Table 1 deals with bulbs having 6 cm inner diameters and various bulb wall thicknesses;
  • Table 2 deals with bulbs having 7 cm outer diameters and various bulb wall thicknesses;
  • Table 3 deals with bulbs having 6 cm outer diameters and various bulb wall thicknesses;
  • Table 4 deals with bulbs having 5 cm outer diameters and various bulb wall thicknesses.
  • the Power in is 90 watts; the heat coupled into the plasma in the initial three seconds is 18 Joules/sec; the initial temperature is 25°C; the final temperature is 900°C; the bulb cp is 1250 J/kg-C; the bulb density is 2.20E+03 kg/m 3 (i.e., 2.20E-06 kg/mm 3 ). From the results reflected in Table 1 - Table 4, the inventors have concluded that start-up time can be proportional to the mass of bulb 42. Therefore, an aspect of the present invention is utilization of a lower quartz mass to effect shorter start-up time of an electrodeless lamp.
  • Another way to assist self-igniting is to maximize the coil current just prior to ignition.
  • This coil current maximization may be important, for example, in systems having a single stage amplification (e.g., 12 to 15 dB) which otherwise loads the lamp head circuit (low Q) and therefore provides lower initial coil voltage.
  • One technique for maximizing coil current is to positionally lower (i.e. reduce the angle ⁇ shown in Fig. 17) the location at which tap 60 (in a modified Hartley self-tuning lamp) joins excitation coil 40.
  • the present invention is not fill-dependent, it appears preferable to use a low pressure rare-gas fill in order to assist self-igniting of the electrodeless lamp.
  • the pressure should preferably be in a range from about 5 to 30 Torr or less, and more preferably below 20 Torr.
  • Example fills include Indium Bromide (1 mg/cc), Argon, and a small amount of Krypton 85.
  • coils such as the coil 40 have been illustrated as having a single turn. It should be understood, however, that the phenomena described herein and principles of the invention are equally applicable to coils having plural turns with the coil size/wavelength relationship being as discussed in the aforementioned PCT Publication No. WO 99/36940. Moreover, coils of differing types of geometries may be employed where advantageous (e.g., to minimize arcing, optimum sizing for quadrature driving, etc.).
  • the lamps described herein and lamps within the scope of the invention can operate in low, mid, and high power ranges.
  • the signals applied to the lamps illustrated herein are preferably in the 200 MHz to 2000 MHz band, with 300 MHz to 900 MHz band being the most preferred frequency band.
  • the basic embodiments shown in Fig. 5, Fig. 6, and Fig. 7 are but examples. As explained below, other oscillator configurations and variations of these basic embodiments are within the scope of the present invention.
  • Fig. 25, Fig. 26, Fig. 27, and Fig. 28 show various Colpitts-type oscillator variations.
  • Fig. 25 shows an equivalent schematic where a high voltage input is added at point 505.
  • the oscillator of Fig. 25 includes amplifier 534 and feedback element 536 connected around high voltage capacitance C1.
  • the feedback element 536 can be a phase shifting element.
  • the excitation coil 540 is shown in series with the load Z (the load being the bulb and plasma).
  • Fig. 26 shows an equivalent schematic for an oscillator driving an electrodeless lamp head circuit where a low voltage input is added at point 606.
  • the oscillator of Fig. 26 primarily differs from that of Fig. 25 by placement of the capacitances and addition of a third capacitance (namely capacitance 664).
  • the high voltage capacitance C1 is much less than the capacitances C2 and 664.
  • the equivalent schematic of Fig. 27 is similar to that of Fig. 26, but shows that amplifier 734 is a high gain transistor or FET with emitter connected both between capacitances C2 and 764 and through resistance 766 to ground.
  • the equivalent schematic of Fig. 28 is similar to that of Fig.
  • Fig. 28 shows an Armstrong -type oscillator variation with its pick-up coil 964 which generates feedback from the resonant excitation coil 940.
  • the amplifier 934 can be a one stage amplifier, or a two stage amplifier (as shown in Fig. 29 as including a first stage amplifier 980.
  • a clamping circuit can be connected, e.g., at point 982 in Fig. 29, to protect one or more of the amplifiers of the oscillator.
  • feedback for oscillation is derived from a choke used in separating DC current from the RF current in the power oscillator.
  • An extra winding is wound on the choke that is used to generate the feedback signal.
  • the level of feedback is controlled by the ratio of this winding to the windings on the choke.
  • the invention employs a self-tuning system to remain at a changing resonant frequency during starting and long term operation of the load (e.g., the lamp head circuit of an electrodeless lamp).
  • the load e.g., the lamp head circuit of an electrodeless lamp.
  • the use of less quartz in the lamp bulb and a higher initial power contribute to self-ignition and reduced start up time.
  • reliable lamp ignition is achieved by increasing coil current prior to ignition.
  • a lower pressure fill can be employed.
  • the system is simplified and the need for frequency adjusting circuits during start up and operation is precluded. Moreover, the lamp will continue to operate with well matched conditions as the lamp ages.
  • Such a self-tuned lamp system prevents the lamp from extinguishing due to the input power being out of resonance with the lamp system.
  • a self-tuned lamp also allows wider manufacturing tolerances, thereby raising yield and lower manufacturing cost.

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

Abstract

Cette invention se rapporte à un système autoréglé, qui comprend un oscillateur (30) et une charge excitée par oscillateur et qui utilise cette charge excitée par oscillateur comme élément de détermination de fréquence du système résonant. Dans un mode de réalisation, la charge excitée par l'oscillateur est constituée par un circuit de tête pour une lampe sans électrode. Le circuit de tête de la lampe sans électrode comprend une bobine d'excitation (40) proche d'une enveloppe ou d'une ampoule (42) renfermant un espace, lequel forme une décharge de plasma, lorsqu'il est allumé. On peut utiliser avec la charge diverses configurations d'oscillateur, telles que des configurations de Hartley modifiées (30A), des configurations de Colpitts (Clapp) modifiées (30P) et des configurations de Armstrong modifiées (30C). On peut également utiliser divers modes de réalisation des circuits de calage (100) pour limiter le signal de réaction appliqué par le système de réaction à une région tolérée par l'amplificateur. Des systèmes autoréglés fonctionnant à haute fréquence et avec une grande puissance sont d'un intérêt particulier pour cette invention. Cette invention présente des exemples de réalisation de lampes sans électrode à haute fréquence et de grande puissance, ainsi que diverses techniques inventives, par exemple pour assurer un gain suffisant et pour améliorer l'allumage/l'auto-démarrage (par exemple réduire le temps de démarrage) de systèmes autoréglés à haute fréquence et de grande puissance. Les techniques et les agencements assurant un gain suffisant pour les systèmes autoréglés de cette invention consistent à choisir la configuration de l'oscillateur, l'amplification multiétage (si nécessaire) et la configuration du système de réaction. L'auto-allumage de la charge est obtenu de nombreuses façons, par exemple à l'aide d'un oscillateur de démarrage spécial; au moyen d'un espace de gaz rare sous basse pression pour l'ampoule de la lampe; et par augmentation du courant dans la bobine d'excitation (par exemple par positionnement sélectif d'une jonction au niveau d'une dérivation (60) de la bobine d'excitation).
PCT/US2000/030154 1999-11-23 2000-11-22 Lampes sans electrode autoreglables WO2001039555A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2001540569A JP2003515875A (ja) 1999-11-23 2000-11-22 自己同調型無電極ランプ
AU15809/01A AU1580901A (en) 1999-11-23 2000-11-22 Self-tuning electrodeless lamps
DE10085223T DE10085223T1 (de) 1999-11-23 2000-11-22 Selbstabstimmende elektrodenlose Lampen

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US16699799P 1999-11-23 1999-11-23
US60/166,997 1999-11-23

Publications (1)

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WO2001039555A1 true WO2001039555A1 (fr) 2001-05-31

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AU (1) AU1580901A (fr)
DE (1) DE10085223T1 (fr)
TW (1) TW480535B (fr)
WO (1) WO2001039555A1 (fr)

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Publication number Priority date Publication date Assignee Title
DE102007014553A1 (de) 2007-03-27 2008-10-02 Schöbel, Jörg, Prof. Dr.-Ing. Elektrodenlose Gasentladungslampe
US7459899B2 (en) 2005-11-21 2008-12-02 Thermo Fisher Scientific Inc. Inductively-coupled RF power source
US8222822B2 (en) 2009-10-27 2012-07-17 Tyco Healthcare Group Lp Inductively-coupled plasma device
US8575843B2 (en) 2008-05-30 2013-11-05 Colorado State University Research Foundation System, method and apparatus for generating plasma
US8994270B2 (en) 2008-05-30 2015-03-31 Colorado State University Research Foundation System and methods for plasma application
US9028656B2 (en) 2008-05-30 2015-05-12 Colorado State University Research Foundation Liquid-gas interface plasma device
US9272359B2 (en) 2008-05-30 2016-03-01 Colorado State University Research Foundation Liquid-gas interface plasma device
US9288886B2 (en) 2008-05-30 2016-03-15 Colorado State University Research Foundation Plasma-based chemical source device and method of use thereof
US9532826B2 (en) 2013-03-06 2017-01-03 Covidien Lp System and method for sinus surgery
US9555145B2 (en) 2013-03-13 2017-01-31 Covidien Lp System and method for biofilm remediation

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102014019645B4 (de) 2014-12-24 2016-10-06 Bernd Hillerich Photoionisationsdetektor mit stabilisierter UV-Quelle

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US4010400A (en) * 1975-08-13 1977-03-01 Hollister Donald D Light generation by an electrodeless fluorescent lamp
US4245178A (en) * 1979-02-21 1981-01-13 Westinghouse Electric Corp. High-frequency electrodeless discharge device energized by compact RF oscillator operating in class E mode
US4485333A (en) * 1982-04-28 1984-11-27 Eg&G, Inc. Vapor discharge lamp assembly
US5103142A (en) * 1990-05-14 1992-04-07 Hella Kg Hueck & Co. Circuit arrangement for ignition and operation of a high pressure gas discharge lamp for motor vehicles
EP0489532A1 (fr) * 1990-12-04 1992-06-10 General Electric Company Lampe à décharge sans électrodes
GB2305311A (en) * 1995-09-18 1997-04-02 Gen Electric Self oscillating drive circuit for an electrodeless discharge lamp
WO1999036940A2 (fr) * 1998-01-13 1999-07-22 Fusion Lighting, Inc. Lampe inductive haute frequence et oscillateur de puissance
US5982108A (en) * 1996-08-14 1999-11-09 U.S. Philips Corporation DC/AC converter for a discharge lamp having a DC offset at the switching element to reduce power loss

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4010400A (en) * 1975-08-13 1977-03-01 Hollister Donald D Light generation by an electrodeless fluorescent lamp
US4245178A (en) * 1979-02-21 1981-01-13 Westinghouse Electric Corp. High-frequency electrodeless discharge device energized by compact RF oscillator operating in class E mode
US4485333A (en) * 1982-04-28 1984-11-27 Eg&G, Inc. Vapor discharge lamp assembly
US5103142A (en) * 1990-05-14 1992-04-07 Hella Kg Hueck & Co. Circuit arrangement for ignition and operation of a high pressure gas discharge lamp for motor vehicles
EP0489532A1 (fr) * 1990-12-04 1992-06-10 General Electric Company Lampe à décharge sans électrodes
GB2305311A (en) * 1995-09-18 1997-04-02 Gen Electric Self oscillating drive circuit for an electrodeless discharge lamp
US5982108A (en) * 1996-08-14 1999-11-09 U.S. Philips Corporation DC/AC converter for a discharge lamp having a DC offset at the switching element to reduce power loss
WO1999036940A2 (fr) * 1998-01-13 1999-07-22 Fusion Lighting, Inc. Lampe inductive haute frequence et oscillateur de puissance

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7459899B2 (en) 2005-11-21 2008-12-02 Thermo Fisher Scientific Inc. Inductively-coupled RF power source
DE102007014553A1 (de) 2007-03-27 2008-10-02 Schöbel, Jörg, Prof. Dr.-Ing. Elektrodenlose Gasentladungslampe
US9028656B2 (en) 2008-05-30 2015-05-12 Colorado State University Research Foundation Liquid-gas interface plasma device
US8575843B2 (en) 2008-05-30 2013-11-05 Colorado State University Research Foundation System, method and apparatus for generating plasma
US8994270B2 (en) 2008-05-30 2015-03-31 Colorado State University Research Foundation System and methods for plasma application
US9272359B2 (en) 2008-05-30 2016-03-01 Colorado State University Research Foundation Liquid-gas interface plasma device
US9288886B2 (en) 2008-05-30 2016-03-15 Colorado State University Research Foundation Plasma-based chemical source device and method of use thereof
US9287091B2 (en) 2008-05-30 2016-03-15 Colorado State University Research Foundation System and methods for plasma application
US8878434B2 (en) 2009-10-27 2014-11-04 Covidien Lp Inductively-coupled plasma device
US8222822B2 (en) 2009-10-27 2012-07-17 Tyco Healthcare Group Lp Inductively-coupled plasma device
US9532826B2 (en) 2013-03-06 2017-01-03 Covidien Lp System and method for sinus surgery
US10524848B2 (en) 2013-03-06 2020-01-07 Covidien Lp System and method for sinus surgery
US9555145B2 (en) 2013-03-13 2017-01-31 Covidien Lp System and method for biofilm remediation

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JP2003515875A (ja) 2003-05-07
DE10085223T1 (de) 2002-10-31
TW480535B (en) 2002-03-21

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