WO2008029445A1 - Discharge lamp lighting apparatus - Google Patents

Discharge lamp lighting apparatus Download PDF

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Publication number
WO2008029445A1
WO2008029445A1 PCT/JP2006/317518 JP2006317518W WO2008029445A1 WO 2008029445 A1 WO2008029445 A1 WO 2008029445A1 JP 2006317518 W JP2006317518 W JP 2006317518W WO 2008029445 A1 WO2008029445 A1 WO 2008029445A1
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WO
WIPO (PCT)
Prior art keywords
discharge lamp
lighting
circuit
discharge
inrush current
Prior art date
Application number
PCT/JP2006/317518
Other languages
French (fr)
Japanese (ja)
Inventor
Satoshi Kominami
Toshiaki Kurachi
Kenichirou Takahashi
Original Assignee
Panasonic Corporation
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 Panasonic Corporation filed Critical Panasonic Corporation
Priority to PCT/JP2006/317518 priority Critical patent/WO2008029445A1/en
Publication of WO2008029445A1 publication Critical patent/WO2008029445A1/en

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Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J65/00Lamps without any electrode inside the vessel; Lamps with at least one main electrode outside the vessel
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00Gas-discharge or vapour-discharge lamps
    • H01J61/02Details
    • H01J61/04Electrodes; Screens; Shields
    • H01J61/06Main electrodes
    • H01J61/067Main electrodes for low-pressure discharge lamps
    • H01J61/0672Main electrodes for low-pressure discharge lamps characterised by the construction of the electrode
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14Circuit arrangements
    • H05B41/26Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28Circuit 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
    • H05B41/2806Circuit 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
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Definitions

  • the present invention relates to a lighting device for an external electrode type discharge lamp that is lit by a dielectric barrier discharge, and in particular, a discharge lamp is provided with a lighting period and a non-lighting period, and is adjusted by changing the time ratio between these periods.
  • the present invention relates to a discharge lamp lighting device that performs light lighting.
  • FIG. 8 is a block diagram showing a conventional configuration of a discharge lamp lighting device using dielectric barrier discharge.
  • a conventional discharge lamp lighting device includes a lighting circuit 100 including a DC power source 110, an inverter circuit 120, a dimming control circuit 130, and a step-up transformer 140, and a discharge lamp 150.
  • the inverter circuit 120 includes a rectangular wave signal generation circuit 121, a drive circuit 122, and a switching circuit 123.
  • the drive circuit 122 includes a rectangular wave signal Vp (see FIG. 9A) having a predetermined frequency (for example, 25 kHz) generated by the rectangular wave signal generation circuit 121, and a PWM (Pulse Width Modulation) from the dimming control circuit 130.
  • Vp rectangular wave signal
  • PWM Pulse Width Modulation
  • the switching circuit 123 Based on the drive signal Vd from the drive circuit 122, the switching circuit 123 converts the DC voltage supplied from the DC power supply 110 into a rectangular wave voltage Vr (see FIG. 9 (d)) having a predetermined frequency (for example, 25 kHz), and boosts the voltage. Output to transformer 140. [0005]
  • the step-up transformer 140 boosts the rectangular wave voltage Vr applied to the primary coil to a high voltage (for example, lkV) rectangular wave voltage Vs (see FIG. 9 (e)), so that both electrodes of the discharge lamp 150 Apply between them and turn on the discharge lamp 150.
  • dimming is performed by changing the duty ratio of the PWM signal Vdim.
  • a first period Ton (lighting period) in which the rectangular wave voltage Vs is applied and a second period Toff (light-out period) in which the rectangular wave voltage Vs is not applied are provided.
  • Dimming (hereinafter referred to as “burst dimming”) for adjusting the brightness (light emission luminance) of the discharge lamp 150 by changing the time ratio (ratio) of the period is performed. For example, if the duty ratio TonZ (Ton + Toff) is set to 70%, the rectangular wave voltage Vs is applied only during a period of 70% of the predetermined period (Ton + Toff). Is 70%.
  • Patent Document 1 discloses a technique for suppressing unnecessary radiation noise by grounding an external electrode provided on the surface of a discharge lamp, particularly in a lamp using an internal / external dielectric noria discharge.
  • Patent Document 2 discloses an example of another countermeasure against unnecessary radiation noise. According to Patent Document 2, especially when a plurality of discharge lamps are lit by a plurality of lighting circuits, the phase of the voltage waveform applied to each discharge lamp is asynchronous with each other and the output power to each lamp is adjusted independently. A technique for suppressing unnecessary radiation noise is disclosed. Patent Document 1: JP 2000-106148 A
  • Patent Document 2 JP-A-8-146198 Disclosure of the invention
  • the above-described conventional discharge lamp lighting device is relatively effective in suppressing unwanted radiation noise in a 100% lighting state (hereinafter referred to as “all-light lighting”) that does not require dimming lighting. .
  • all-light lighting a 100% lighting state
  • all-light lighting a 100% lighting state
  • the new radiation that unnecessary radiation noise cannot be sufficiently suppressed. The problem was revealed.
  • the present invention has been made in view of powerful circumstances, and is suitable for a discharge lamp lighting device using a dielectric barrier discharge. Another object of the present invention is to provide a discharge lamp lighting device that can sufficiently suppress unnecessary radiation noise.
  • the inventor of the present invention examined the cause of unnecessary radiation noise generated during dimming in a lighting device using a dielectric barrier discharge. As a result, the rectangular wave voltage was turned off during burst dimming. We found that this is due to the inrush current that occurs when the force changes to ON. Based on this fact, the present inventor has conceived the idea of suppressing the inrush current to the discharge lamp generated during burst dimming in order to suppress unnecessary radiation noise during dimming! did.
  • the discharge lamp lighting device is a device that lights a discharge lamp that emits light by dielectric barrier discharge.
  • the discharge lamp lighting device applies dimming lighting by applying a rectangular wave high-frequency voltage to the discharge lamp, providing the discharge lamp with a lighting period and an extinguishing period, and changing the time ratio between the lighting period and the extinguishing period.
  • an inductive element is connected in series between the discharge lamp and the lighting circuit. With this configuration, inductive elements limit the inrush current that flows each time the discharge lamp re-lights after the extinguishing period when dimming lighting is performed by changing the time ratio between the lighting period and the extinguishing period. Radiation noise is suppressed.
  • the inrush current suppression action can reduce power consumption, and it is possible to suppress unnecessary radiation noise while improving the circuit efficiency of the lighting circuit.
  • the impedance of the inductive element is set so that the value at a measurement frequency of 100 MHz is 200 ⁇ or more and 22 k ⁇ or less.
  • inrush current can be suppressed more efficiently. Therefore, unnecessary radiation noise can be efficiently suppressed.
  • the lighting circuit may include a step-up transformer!
  • an inductive element is connected in series between the discharge lamp and the step-up transformer.
  • the discharge gas sealed in the discharge lamp preferably contains xenon and substantially does not contain mercury. Since the discharge gas sealed in the discharge lamp is xenon, it is excellent in ionization and excitation efficiency during discharge and can be a high-intensity light source. In addition, since the discharge gas does not contain mercury, adverse effects on the environment can be reduced.
  • the inrush current that flows through the discharge lamp every time the discharge lamp re-lights after the extinguishing period is applied to the discharge lamp. It is limited by the inductive element or resistance element (inrush current suppression circuit) connected in series, which can greatly reduce unnecessary radiation noise during dimming.
  • FIG. 1 is a block diagram showing an example of a discharge lamp lighting device according to the present invention.
  • FIG. 2 Cross section of the discharge lamp of the present invention
  • FIG. 3 is a circuit diagram showing an example of a lighting circuit in the discharge lamp of the present invention.
  • FIG. 5 is a diagram showing another configuration example of the discharge lamp
  • FIG. 6 is a diagram showing still another configuration example of the discharge lamp.
  • FIG. 8 is a block diagram showing the configuration of a conventional discharge lamp lighting device
  • FIG. 9 Waveform diagrams at various parts of a conventional discharge lamp lighting device
  • the inventor of the present application conducted extensive research to elucidate the cause of unnecessary radiation noise, and as a result, measured the current I flowing through the discharge lamp with a resolution higher than the resolution for measuring the frequency of the voltage Vs applied to the discharge lamp.
  • the spike-like current described below is the cause of unwanted radiation noise.
  • the inventor of the present application newly noticed the discovery of the spike-like current, and came to the present invention based on this discovery.
  • FIG. 7 is a diagram schematically showing a waveform of a high-pressure rectangular wave voltage Vs applied to a discharge lamp that emits light by dielectric barrier discharge and a flowing current I.
  • Fig. 7 (a) shows 100% luminance, that is, the waveform when all the lights are on
  • Fig. 7 (b) shows the waveform when burst dimming.
  • Fig. 7 (a) when all the lights are on, an almost constant pulse current flows when the polarity of the high-voltage rectangular wave voltage Vs is reversed.
  • spike-like inrush current Isp flows in the first pulse current when the discharge lamp 10 is turned on again after the extinguishing period, and then it is the same as when all lights are turned on. Pulse current Ip flows (see enlarged view A in Fig. 7 (b)).
  • the peak value of the spike-like inrush current shown in Fig. 7 (b) may be 3 to 5 times the peak value of the pulse current.
  • This phenomenon does not occur in other cold cathode lamps or the like, or even if it occurs, a large spike-shaped inrush current does not flow so far.
  • This phenomenon occurs when the voltage applied to the dielectric barrier discharge lamp is a rectangular wave voltage. This phenomenon is considered to be peculiar to discharge lamps. In other words, the cold cathode lamp is a resistive load, but the dielectric barrier discharge lamp is a capacitive load. Therefore, a spike-like inrush current tends to flow at the start of discharge of the charge accumulated in the capacitive load. It is considered to be.
  • spike-like inrush current is one cause of unnecessary radiation noise based on the above-described event.
  • the present inventor has conceived the idea of suppressing spike-like inrush current in order to suppress unnecessary radiation noise, and has devised a discharge lamp lighting device shown below.
  • FIG. 1 is a block diagram showing an embodiment of a discharge lamp lighting device of the present invention.
  • the discharge lamp lighting device is a device that drives a discharge lamp 10 that emits light by dielectric barrier discharge, and has a burst dimming function.
  • the discharge lamp lighting device includes a DC power supply 40, an inverter circuit 50, a dimming control circuit 60,
  • the lighting circuit 20 including the step-up transformer 70 is provided.
  • an inrush current suppression circuit 30 that suppresses an inrush current flowing into the discharge lamp 10 is connected in series between the lighting circuit 20 and the discharge lamp 10.
  • the inrush current suppression circuit 30 limits the inrush current to the discharge lamp 10 and suppresses unnecessary radiation noise.
  • FIG. 2 shows an example of the configuration of the discharge lamp 10.
  • FIG. 2 (a) is a side sectional view
  • FIG. 2 (b) is an axial sectional view at the central portion of the discharge lamp 10.
  • the discharge lamp 10 is a mixed gas containing xenon as a discharge gas in a cylindrical arc tube 11 formed of borosilicate glass, soda glass or the like having excellent transmittance in visible light (wavelength: 380 ⁇ m to 770 nm). Is enclosed and formed.
  • the sealing pressure is set in the range of 5 to 40 kPa, for example.
  • the mixed gas components other than xenon are helium, neon, argon, krypton, etc., and the mixing ratio is 6: 4, for example.
  • a phosphor 15 is applied to the inner surface of the arc tube 11.
  • Inside one end of the arc tube 11 is an internal electrode 12 made of metal such as tungsten or nickel.
  • the lead wire 13 is electrically led out of the arc tube 11.
  • an external electrode 14 made of metal such as aluminum or copper is disposed outside the arc tube 11.
  • the DC power supply 40 is configured by a DC / DC converter using a smoothing rectifier circuit, a chopper circuit, a DC voltage source (battery), etc., and rectifies a commercial AC power supply voltage to generate DC power. Pressure and output to the inverter circuit 50.
  • the inverter circuit 50 includes a rectangular wave signal generation circuit 51, a drive circuit 52, and a switching circuit 53.
  • the rectangular wave signal generation circuit 51 generates a rectangular wave signal Vp having a predetermined frequency and outputs it to the drive circuit 52.
  • the frequency of the rectangular wave signal Vp determines the lighting frequency of the discharge lamp 10 and is set in the range of 10 to: LOOkHz.
  • the drive circuit 52 generates a drive signal Vd based on the rectangular wave signal Vp input from the rectangular wave signal generation circuit 51 and the dimming signal Vdim input from the dimming control circuit 60, and supplies the driving signal Vd to the switching circuit 53. Output.
  • the switching circuit 53 is connected to the DC power supply 40, converts the DC voltage supplied from the DC power supply 40 to the rectangular wave voltage Vr based on the drive signal Vd input from the drive circuit 52, and converts the converted rectangular wave. Apply voltage Vr to the primary side (primary coil) of step-up transformer 70.
  • the step-up transformer 70 boosts the rectangular wave voltage Vr applied to the primary coil to a high-voltage rectangular wave voltage Vs and applies it between both electrodes of the discharge lamp 10 via the inrush current suppression circuit 30. .
  • the voltage value of the high-voltage rectangular wave voltage Vs is about 1 to 3 kV.
  • the dimming control circuit 60 receives an instruction signal Sig for instructing an increase in the emission luminance of the discharge lamp 10 and a decrease in Z, and performs dimming according to the instruction signal Sig.
  • An optical signal Vdim is generated and output to the drive circuit 52.
  • the instruction signal Sig is a signal having a signal level of, for example, 0 to 5 V inputted from the outside, and the signal level indicates a set value of the light emission luminance of the discharge lamp 10.
  • the dimming signal Vdim is a PWM signal with a frequency lower than the frequency of the rectangular wave signal Vp, and its frequency is set to 100 to lkHz.
  • the pulse width of the dimming signal Vdim changes according to the instruction signal Sig.
  • the inrush current suppression circuit 30 is composed of an inductive element.
  • the inrush current suppression circuit 30 suppresses the inrush current that flows through the discharge lamp 10 when the discharge lamp 10 is turned on again after the extinguishing period (OFF) during burst dimming and Thus, it has an impedance that does not affect the current flowing through the discharge lamp 10.
  • inrush current suppression The circuit 30 preferably has an impedance of 200 ⁇ or more at a measurement frequency of 100 MHz.
  • FIG. Figure 3 shows the configuration of a push-pull lighting circuit.
  • FIG. 4 shows voltage waveforms at various parts of the lighting circuit 20 of FIG.
  • the operation of the lighting circuit 20 will be described with reference to FIGS.
  • the rectangular wave signal generation circuit 51 generates a rectangular wave signal Vp having a predetermined frequency (for example, 25 kHz) shown in FIG.
  • the rectangular wave signal generation circuit 51 can be constituted by a timer IC or the like, for example.
  • the drive circuit 52 includes a flip-flop circuit 54, an AND circuit 55, and a NOR circuit 56.
  • the rectangular wave signal Vp from the rectangular wave signal generation circuit 51 is input to the CK terminal as a clock signal
  • the dimming signal Vdim from the dimming control circuit 60 is input to the D terminal as a data signal. Entered.
  • the flip-flop circuit 52 captures the signal level of the data signal (dimming signal Vdim) at the rising edge of the clock signal (rectangular wave signal Vp), holds the captured signal level at other than the rising edge, and outputs a non-inverted output signal.
  • Q and inverted output signal ZQ are output.
  • the AND circuit 55 inputs the non-inverted output signal Q from the flip-flop circuit 54 and the rectangular wave signal Vp from the rectangular wave signal generation circuit 51, and outputs the drive signal Vdl shown in Fig. 4 (c). To do.
  • the NOR circuit 56 inputs the inverted output signal ZQ from the flip-flop circuit 54 and the rectangular wave signal Vp from the rectangular wave signal generation circuit 51, and outputs the drive signal Vd2 shown in FIG. 4 (d).
  • the drive signals Vdl and Vd2 are signals having opposite polarities, and when the drive signal Vdl is high level, the drive signal Vd2 is low level. Conversely, when the drive signal Vdl is low level, the drive signal Vd2 is high level.
  • the switching circuit 53 includes FETs 57 and 58.
  • the drive signals Vdl and Vd2 are input to the gates of the FETs 57 and 58, respectively.
  • the FETs 57 and 58 are alternately turned ON and OFF according to the drive signals Vdl and Vd2, respectively, and the rectangular wave voltages Vrl and Vr2 shown in FIGS. 4 (e) and (f) are applied to the primary side of the step-up transformer 70.
  • the dimming control circuit 60 includes a triangular wave generation circuit 61 and a comparator 62.
  • the triangular wave generation circuit 61 outputs a triangular wave signal of, for example, 250 Hz, which determines the frequency of burst dimming, to the comparator 62.
  • the triangular wave generating circuit 61 can be composed of, for example, an OP amplifier. Co
  • the triangular wave signal from the triangular wave generating circuit 61 is inputted to the inverting input of the comparator 62, and the instruction signal Sig for instructing the increase of the emission luminance Z of the discharge lamp 10 is inputted to the non-inverting input.
  • the comparator 62 compares the triangular wave signal with the instruction signal Sig, and outputs a dimming signal Vdim of 250 Hz having a noise width corresponding to the instruction signal Sig to the drive circuit 52.
  • the step-up transformer 70 is composed of a primary winding and a secondary winding.
  • a DC power supply 40 and FETs 57 and 58 of a switching circuit 53 are connected to the primary side of the step-up transformer 70, and a discharge lamp 10 is connected to the secondary side via an inrush current suppression circuit 30.
  • the step-up transformer 70 uses the rectangular wave voltages Vrl and Vr2 input to the primary side according to the step-up ratio determined by the ratio of the primary and secondary windings to the high voltage rectangle shown in Fig. 4 (g). The voltage is increased to a wave voltage Vs (for example, lkV) and applied to the discharge lamp 10.
  • Vs for example, lkV
  • a rectangular wave voltage is used instead of a sine wave voltage. This is because the xenon excimer emission increases and more ultraviolet rays are emitted when the rectangular wave voltage is used, so that the light emission efficiency is improved.
  • an inrush current suppression circuit 30 is connected in series between the discharge lamp 10 and the step-up transformer 70.
  • the effect of the inrush current suppression circuit 30 will be described.
  • the measurement was performed at 25 kHz, using a liquid crystal backlight unit using two discharge lamps with 2 lkPa of 6: 4 xenon-argon mixed gas in an arc tube with an inner diameter of 2 mm, an outer diameter of 2.6 mm, and a length of 160 mm. It was lit with a square wave of lkV. The frequency of burst dimming is 250Hz.
  • the inrush current suppression circuit 30 is an inductive element with an impedance of 600 ⁇ at a measurement frequency of 100 MHz. Are connected to the discharge lamp 10 in series.
  • Unnecessary radiated noise is regulated in various ways depending on the equipment, but here is the standard for measurement methods complied by the International Special Committee on Radio Interference of the International Electrotechnical Commission (IEC). Unwanted radiation noise was measured by a method compliant with CISPR25. Table 1 shows the results measured by the CISPR25 method.
  • Table 1 shows the results of measuring broadband unwanted radiation noise in each frequency band. Normally, CISPR25 ⁇ koo! /, The regulation of unwanted radiation noise is in the frequency range of 150kHz to 1GHz, and there is a regulation of unwanted radiation noise in a specific discrete frequency range. Only the measured frequency range is displayed as a representative.
  • the impedance value of the inductive element of the inrush current suppression circuit 30 is changed to reduce unnecessary radiation noise.
  • Table 2 shows the measurement results. Except for the impedance value of the inrush current suppression circuit 30, the measurement sample and measurement method are the same as in Table 1.
  • the upper limit value of impedance at 100 MHz that can suppress spike-like inrush current is not limited to 2000 ⁇ .
  • Table 2 the effect of reducing unwanted radiation noise cannot be expected even if the impedance is too high.
  • the impedance at 100 MHz is too large, the normal pulse current waveform may be affected and the luminous efficiency of the discharge lamp 10 may change.
  • the inventor of the present application As a result of the measurement, it was found that the impedance of the inrush current suppression circuit 30 is preferably not less than 200 ⁇ and not more than 22 k ⁇ in practice when the measurement frequency is 100 MHz.
  • the measurement was performed by connecting ten inductive elements (product number: BLM21BD222SN1L, manufactured by Murata Manufacturing Co., Ltd.) having an impedance of 2.2 k ⁇ at 100 MHz as the inrush current suppression circuit 30 in series.
  • the upper limit of the impedance at 100MHz may exceed 22k ⁇ ! /.
  • the reason for specifying the impedance value of the inductive element in the 100 MHz band in the present invention is that the spike-like inrush current is not affected by the pulse current in FIG. It is for suppressing.
  • the inrush current suppression circuit 30 having impedance in the discharge lamp operating frequency band (kHz band, for example, 10 kHz or more and 100 kHz or less) is inserted, the pulse current in FIG. Efficiency is reduced.
  • the pulse current is not intended for the increased pulse current (starting current in this document), which is the subject of JP-A-6-96891. Impedance is specified for spike-like currents that occur in a much shorter time.
  • an inductive element having the above impedance range (value at 100 MHz is 200 ⁇ or more and 22 k ⁇ or less) has a small impedance value in the lighting frequency range (kHz band, for example, 10 kHz or more and 100 kHz or less). This had almost no effect on the luminous efficiency and circuit efficiency.
  • FIG. 2 shows a force that shows a configuration in which one internal electrode 12 is disposed inside the discharge lamp 10 force arc tube 11 and one external electrode 14 is disposed outside the arc tube 11.
  • a rare gas discharge lamp having a plurality of internal electrodes 12 and a rare gas discharge lamp having a plurality of external electrodes 14 are not limited to the configuration shown in FIG.
  • the configuration of the discharge lamp is such that the internal electrode 12 is disposed at one end of the arc tube 11 and a plurality of external electrodes 14a, 14b, as in the discharge lamp 81 shown in FIG. ⁇ 14h emits light
  • a configuration arranged outside the tube 11 may also be used.
  • the internal electrodes 12a and 12b may be disposed at both ends of the arc tube 11, and one external electrode 14 may be disposed outside the arc tube 11.
  • the internal electrodes 12a, 12b are arranged at both ends of the arc tube 11, and a plurality of external electrodes 14a, 14b,.
  • positioned outside may be sufficient.
  • the axial cross section at the center of the discharge lamps 81, 82, 83 is the same as in FIG. 2 (b). Further, three or more internal electrodes 12 may be provided.
  • the shape of the external electrode 14 of the discharge lamp 10 may be away from the arc tube 11 which does not need to be in contact with the outer surface of the arc tube 11, or may be of the planar shape shown in FIG. It is not limited to anything.
  • the external electrode 85 having a concave cross section in the tube axis direction is disposed outside the arc tube 11 so as to partially cover the circumferential direction of the arc tube 11. It may be configured.
  • the external electrode 14 may be wound around the outer surface of the arc tube 11 in a spiral manner.
  • the discharge gas sealed in the arc tube 11 is a mixed gas containing xenon.
  • the discharge gas may not be a mixed gas but may be a gas of 100% xenon.
  • the lighting circuit 20 has been described with the lighting circuit having the push-pull method and the configuration, other methods such as a half-bridge method and a full-bridge method may be used. In this case, it goes without saying that the configuration of the boosting transformer 70 changes.
  • the rectangular wave signal generation circuit 51, the drive circuit 52, and the dimming control circuit 53 may have other configurations, for example, a single microcomputer. Further, a PWM signal may be directly input from the outside as the instruction signal Sig from the outside. In this case, the instruction signal Sig may be input to the drive circuit 52 as the dimming signal Vdim.
  • a force using FETs 57 and 58 as a switching element of the switching circuit 53 may be another switching element, for example, a bipolar transistor.
  • the discharge lamp lighting device can be used as a light source for various purposes, and is particularly useful as a backlight for a liquid crystal display or the like, a light source for reading a document for a scanner or a copy, and the like.

Abstract

A discharge lamp light apparatus, which uses the dielectric barrier discharge, comprises a lighting circuit (20) that applies a high frequency voltage having a rectangular waveform to a discharge lamp (10) to vary a time ratio of lighting-on and lighting-off time periods established for the discharge lamp, thereby providing a modulated light; and an inductive element (30) that is connected in series between the discharge lamp (10) and the lighting circuit (20) and that has an impedance value between 200 ohms and 22 kilo-ohms at a frequency of 100 MHz. The inductive element (30) suppresses the inrush current flowing into the discharge lamp (10) during providing the modulated light, thereby reducing unwanted radiant noise.

Description

明 細 書  Specification
放電ランプ点灯装置  Discharge lamp lighting device
技術分野  Technical field
[0001] 本発明は、誘電体バリア放電により点灯する外部電極式の放電ランプの点灯装置 に関し、特に、放電ランプに点灯期間と消灯期間を設け、それらの期間の時間比を 変化させることにより調光点灯を行う放電ランプ点灯装置に関する。  TECHNICAL FIELD [0001] The present invention relates to a lighting device for an external electrode type discharge lamp that is lit by a dielectric barrier discharge, and in particular, a discharge lamp is provided with a lighting period and a non-lighting period, and is adjusted by changing the time ratio between these periods. The present invention relates to a discharge lamp lighting device that performs light lighting.
背景技術  Background art
[0002] 近年、液晶ディスプレイ等のバックライト用途として、誘電体バリア放電により点灯す る外部電極式の希ガス放電ランプの研究が盛んに行われている。これは、希ガス放 電ランプは水銀が不要であるため、水銀蒸気圧の上昇に伴う発光効率の低下を招く ことなく、また環境上好ましいとの理由に基づくものである。誘電体バリア放電を用い た点灯動作においては、駆動電圧の印加により誘電対層を充電し、駆動電圧が反転 したときに発生する高圧により放電を起こさせる作用を用いるため、駆動電圧として高 周波の矩形波電圧が用いられる。  In recent years, research on external electrode type rare gas discharge lamps that are lit by dielectric barrier discharge has been actively conducted as backlight applications such as liquid crystal displays. This is based on the reason that the rare gas discharge lamp does not require mercury and therefore does not cause a decrease in luminous efficiency due to an increase in mercury vapor pressure and is environmentally preferable. In a lighting operation using a dielectric barrier discharge, the dielectric pair layer is charged by applying a driving voltage, and a discharge is caused by a high voltage generated when the driving voltage is reversed. A square wave voltage is used.
[0003] 図 8は誘電体バリア放電による放電ランプ点灯装置の従来の構成を示すブロック図 である。従来の放電ランプ点灯装置は、直流電源 110、インバータ回路 120、調光制 御回路 130および昇圧トランス 140を含む点灯回路 100と、放電ランプ 150とを備え ている。  FIG. 8 is a block diagram showing a conventional configuration of a discharge lamp lighting device using dielectric barrier discharge. A conventional discharge lamp lighting device includes a lighting circuit 100 including a DC power source 110, an inverter circuit 120, a dimming control circuit 130, and a step-up transformer 140, and a discharge lamp 150.
[0004] インバータ回路 120は、矩形波信号生成回路 121、駆動回路 122、スイッチング回 路 123とから構成される。駆動回路 122は、矩形波信号生成回路 121で生成した所 定周波数 (例えば 25kHz)の矩形波信号 Vp (図 9 (a)参照)と、調光制御回路 130か らの PWM (Pulse Width Modulation)信号 Vdim (図 9 (b)参照)とから、 PWM信号 V dimの ON期間(ノヽィレベル)に対応したバースト波形を生成し、駆動信号 Vdを(図 9 (c)参照)としてスイッチング回路 123に出力する。スイッチング回路 123は駆動回路 122からの駆動信号 Vdに基づいて、直流電源 110から供給される直流電圧を所定 周波数 (例えば 25kHz)の矩形波電圧 Vr (図 9 (d)参照)に変換し、昇圧トランス 140 に出力する。 [0005] 昇圧トランス 140は、 1次コイルに印加された矩形波電圧 Vrを高電圧 (例えば lkV) の矩形波電圧 Vs (図 9 (e)参照)に昇圧して、放電ランプ 150の両電極間に印加し、 放電ランプ 150を点灯させる。 The inverter circuit 120 includes a rectangular wave signal generation circuit 121, a drive circuit 122, and a switching circuit 123. The drive circuit 122 includes a rectangular wave signal Vp (see FIG. 9A) having a predetermined frequency (for example, 25 kHz) generated by the rectangular wave signal generation circuit 121, and a PWM (Pulse Width Modulation) from the dimming control circuit 130. A burst waveform corresponding to the ON period (noise level) of the PWM signal V dim is generated from the signal Vdim (see Fig. 9 (b)), and the drive signal Vd (see Fig. 9 (c)) is generated in the switching circuit 123. Output. Based on the drive signal Vd from the drive circuit 122, the switching circuit 123 converts the DC voltage supplied from the DC power supply 110 into a rectangular wave voltage Vr (see FIG. 9 (d)) having a predetermined frequency (for example, 25 kHz), and boosts the voltage. Output to transformer 140. [0005] The step-up transformer 140 boosts the rectangular wave voltage Vr applied to the primary coil to a high voltage (for example, lkV) rectangular wave voltage Vs (see FIG. 9 (e)), so that both electrodes of the discharge lamp 150 Apply between them and turn on the discharge lamp 150.
[0006] さらに、この構成において、 PWM信号 Vdimのデューティ比を変化させることによる 調光が行われる。一般に、放電ランプ 150を調光する場合、矩形波電圧 Vsを印加す る第 1期間 Ton (点灯期間)と、矩形波電圧 Vsを印加しない第 2期間 Toff (消灯期間 )とを設け、それらの期間の時間的割合 (比率)を変化させることにより、放電ランプ 15 0の発光の明るさ (発光輝度)を調節する調光 (以下「バースト調光」と 、う。 )が行われ る。例えば、デューティ比 TonZ (Ton+Toff)を 70%とすれば、所定周期(Ton+T off)のうちの 70%の期間のみ、矩形波電圧 Vsが印加されるため、放電ランプ 150の 発光輝度は 70%となる。  [0006] Further, in this configuration, dimming is performed by changing the duty ratio of the PWM signal Vdim. In general, when dimming the discharge lamp 150, a first period Ton (lighting period) in which the rectangular wave voltage Vs is applied and a second period Toff (light-out period) in which the rectangular wave voltage Vs is not applied are provided. Dimming (hereinafter referred to as “burst dimming”) for adjusting the brightness (light emission luminance) of the discharge lamp 150 by changing the time ratio (ratio) of the period is performed. For example, if the duty ratio TonZ (Ton + Toff) is set to 70%, the rectangular wave voltage Vs is applied only during a period of 70% of the predetermined period (Ton + Toff). Is 70%.
[0007] 一方、誘電体バリア放電を用いた放電ランプ点灯装置の課題の 1つとして不要輻 射ノイズが大きい点があげられる。これは、誘電体バリア放電を用いた放電ランプが、 従来の放電ランプ、例えば陰極ランプと比較して、大電流でかつパルス状の電流が 流れるためである。不要輻射ノイズは、ラジオ、テレビへの雑音混入さらには電子機 器の誤動作など電磁障害の原因となり得るため、一般に、すべての電子機器は不要 輻射ノイズの基準値が定められており、近年は特に、不要輻射ノイズの抑制に対する 要求が強くなつてきている。  [0007] On the other hand, one of the problems of a discharge lamp lighting device using dielectric barrier discharge is that unnecessary radiation noise is large. This is because a discharge lamp using a dielectric barrier discharge has a larger current and a pulsed current flow than a conventional discharge lamp such as a cathode lamp. Unwanted radiation noise can cause electromagnetic interference such as radio and television noises and malfunctions of electronic equipment.In general, all electronic equipment has a standard value for unwanted radiation noise. There is a growing demand for suppression of unwanted radiation noise.
[0008] 誘電体バリア放電を用いた放電ランプ点灯装置の不要輻射ノイズ対策の一例が、 特許文献 1に開示されている。特許文献 1によれば、特に内部一外部方式の誘電体 ノリア放電を用いたランプにおいて、放電ランプ表面に設けられた外部電極を接地 することにより不要輻射ノイズを抑制する手法を開示している。  An example of measures against unwanted radiation noise in a discharge lamp lighting device using dielectric barrier discharge is disclosed in Patent Document 1. Patent Document 1 discloses a technique for suppressing unnecessary radiation noise by grounding an external electrode provided on the surface of a discharge lamp, particularly in a lamp using an internal / external dielectric noria discharge.
[0009] また、別の不要輻射ノイズ対策の一例が、特許文献 2に開示されている。特許文献 2によれば、特に複数の放電ランプを複数の点灯回路で点灯するときにおいて、各 放電ランプに印加される電圧波形の位相を互いに非同期でかつ各ランプへの出力 電力を独立して調整することにより不要輻射ノイズを抑制する手法を開示している。 特許文献 1 :特開 2000— 106148号公報  [0009] Further, Patent Document 2 discloses an example of another countermeasure against unnecessary radiation noise. According to Patent Document 2, especially when a plurality of discharge lamps are lit by a plurality of lighting circuits, the phase of the voltage waveform applied to each discharge lamp is asynchronous with each other and the output power to each lamp is adjusted independently. A technique for suppressing unnecessary radiation noise is disclosed. Patent Document 1: JP 2000-106148 A
特許文献 2 :特開平 8— 146198号公報 発明の開示 Patent Document 2: JP-A-8-146198 Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0010] 上述した従来の放電ランプ灯点灯装置は、調光点灯をして ヽない 100%点灯の状 態 (以下「全光点灯」という。)においては、比較的不要輻射ノイズ抑制効果がある。し かし、上記のような点灯期間と消灯期間を繰り返しその時間的割合を変化させること により調光を行うバースト調光の場合には、十分に不要輻射ノイズを抑制できな 、と いう新たな課題が判明した。  [0010] The above-described conventional discharge lamp lighting device is relatively effective in suppressing unwanted radiation noise in a 100% lighting state (hereinafter referred to as “all-light lighting”) that does not require dimming lighting. . However, in the case of burst dimming in which dimming is performed by repeating the lighting period and the extinguishing period as described above and changing the time ratio, the new radiation that unnecessary radiation noise cannot be sufficiently suppressed. The problem was revealed.
[0011] 本発明は力かる事情に鑑みてなされたものであり、誘電体バリア放電を用いた放電 ランプ点灯装置にお!、て、全光点灯時のみならず調光点灯時にお!、ても十分に不 要輻射ノイズを抑制できる放電ランプ点灯装置の提供を目的とする。  [0011] The present invention has been made in view of powerful circumstances, and is suitable for a discharge lamp lighting device using a dielectric barrier discharge. Another object of the present invention is to provide a discharge lamp lighting device that can sufficiently suppress unnecessary radiation noise.
課題を解決するための手段  Means for solving the problem
[0012] 本発明の発明者は、誘電体バリア放電を用いた点灯装置において調光時に発生 する不要輻射ノイズの発生原因を検討したところ、不要輻射ノイズがバースト調光時 に矩形波電圧が OFF力 ONへ変化したときに発生する突入電流に起因することを 見出した。そしてその事実に基づき、本発明者は調光時の不要輻射ノイズを抑制す るためにバースト調光時に発生する放電ランプへの突入電流を抑制すればよ!、と!/、 う思想に想到した。  [0012] The inventor of the present invention examined the cause of unnecessary radiation noise generated during dimming in a lighting device using a dielectric barrier discharge. As a result, the rectangular wave voltage was turned off during burst dimming. We found that this is due to the inrush current that occurs when the force changes to ON. Based on this fact, the present inventor has conceived the idea of suppressing the inrush current to the discharge lamp generated during burst dimming in order to suppress unnecessary radiation noise during dimming! did.
[0013] 本発明に係る放電ランプ点灯装置は、誘電体バリア放電によって発光する放電ラ ンプを点灯させる装置である。その放電ランプ点灯装置は、放電ランプに矩形波の 高周波電圧を印加し、放電ランプに点灯期間と消灯期間を設け、点灯期間と消灯期 間の時間比を変化させることにより調光点灯を行う点灯回路を備える。さらに放電ラン プは放電ランプと点灯回路の間に直列に誘導性素子を接続する。この構成により、 点灯期間と消灯期間の時間比を変化させることにより調光点灯した場合の、消灯期 間後に放電ランプが再点灯する毎に流れる突入電流が誘導性素子により制限され、 これにより不要輻射ノイズが抑制される。突入電流抑制作用により、電力消費を軽減 でき、点灯回路の回路効率低下を改善しつつ不要輻射ノイズの抑制が可能となる。  The discharge lamp lighting device according to the present invention is a device that lights a discharge lamp that emits light by dielectric barrier discharge. The discharge lamp lighting device applies dimming lighting by applying a rectangular wave high-frequency voltage to the discharge lamp, providing the discharge lamp with a lighting period and an extinguishing period, and changing the time ratio between the lighting period and the extinguishing period. Provide circuit. In addition, an inductive element is connected in series between the discharge lamp and the lighting circuit. With this configuration, inductive elements limit the inrush current that flows each time the discharge lamp re-lights after the extinguishing period when dimming lighting is performed by changing the time ratio between the lighting period and the extinguishing period. Radiation noise is suppressed. The inrush current suppression action can reduce power consumption, and it is possible to suppress unnecessary radiation noise while improving the circuit efficiency of the lighting circuit.
[0014] 特に、誘導性素子のインピーダンスを、測定周波数 100MHzにおける値が 200 Ω 以上かつ 22k Ω以下に設定する。これにより、突入電流をより効率的に抑制すること ができ、不要輻射ノイズを効率的に抑制できる。 In particular, the impedance of the inductive element is set so that the value at a measurement frequency of 100 MHz is 200 Ω or more and 22 kΩ or less. As a result, inrush current can be suppressed more efficiently. Therefore, unnecessary radiation noise can be efficiently suppressed.
[0015] また、点灯回路は昇圧トランスを含んでもよ!ヽ。この場合、放電ランプと昇圧トランス の間に直列に誘導性素子が接続される。  [0015] The lighting circuit may include a step-up transformer! In this case, an inductive element is connected in series between the discharge lamp and the step-up transformer.
[0016] また、放電ランプに封入された放電用ガスはキセノンを含み、かつ実質的に水銀を 含まないのが好ましい。放電ランプに封入された放電用ガスがキセノンであることによ り、放電時の電離及び励起効率に優れ、高輝度の光源とすることができる。また、放 電用ガスが水銀を含まないことにより環境に対する悪影響を軽減できる。  [0016] The discharge gas sealed in the discharge lamp preferably contains xenon and substantially does not contain mercury. Since the discharge gas sealed in the discharge lamp is xenon, it is excellent in ionization and excitation efficiency during discharge and can be a high-intensity light source. In addition, since the discharge gas does not contain mercury, adverse effects on the environment can be reduced.
発明の効果  The invention's effect
[0017] 本発明によれば、点灯期間と消灯期間の時間比を変化させることにより調光を行う 場合に、消灯期間後に放電ランプが再点灯する毎に放電ランプに流れる突入電流 が放電ランプに直列に接続された誘導性素子または抵抗素子 (突入電流抑制回路) により制限され、これにより調光時の不要輻射ノイズを大幅に低減できる。  [0017] According to the present invention, when dimming is performed by changing the time ratio between the lighting period and the extinguishing period, the inrush current that flows through the discharge lamp every time the discharge lamp re-lights after the extinguishing period is applied to the discharge lamp. It is limited by the inductive element or resistance element (inrush current suppression circuit) connected in series, which can greatly reduce unnecessary radiation noise during dimming.
図面の簡単な説明  Brief Description of Drawings
[0018] [図 1]本発明の放電ランプ点灯装置の一例を示すブロック図 FIG. 1 is a block diagram showing an example of a discharge lamp lighting device according to the present invention.
[図 2]本発明の放電ランプの断面図  [Fig. 2] Cross section of the discharge lamp of the present invention
[図 3]本発明の放電ランプにおける点灯回路の一例を示す回路図  FIG. 3 is a circuit diagram showing an example of a lighting circuit in the discharge lamp of the present invention.
[図 4]点灯回路の各部における電圧波形図  [Figure 4] Voltage waveform diagram at each part of lighting circuit
[図 5]放電ランプの他の構成例を示す図  FIG. 5 is a diagram showing another configuration example of the discharge lamp
[図 6]放電ランプのさらに他の構成例を示す図  FIG. 6 is a diagram showing still another configuration example of the discharge lamp.
[図 7]放電ランプの全光点灯時及び調光点灯時の電圧、電流波形図  [Fig.7] Voltage and current waveforms when the discharge lamp is fully lit and dimmed
[図 8]従来の放電ランプ点灯装置の構成を示すブロック図  FIG. 8 is a block diagram showing the configuration of a conventional discharge lamp lighting device
[図 9]従来の放電ランプ点灯装置の各部における波形図  [Fig. 9] Waveform diagrams at various parts of a conventional discharge lamp lighting device
符号の説明  Explanation of symbols
[0019] 10、 81、 82、 83、 84、 150 放電ランプ [0019] 10, 81, 82, 83, 84, 150 Discharge lamp
11 発光管  11 arc tube
12、 12aゝ 12b 内咅隨極  12, 12a ゝ 12b Inner pole
13、 13aゝ 13b リード線  13, 13a ゝ 13b Lead wire
14、 14a〜14h、 85 外部電極 20、 100 点灯回路 14, 14a-14h, 85 External electrode 20, 100 lighting circuit
30 突入電流抑制回路  30 Inrush current suppression circuit
40 直流電源  40 DC power supply
50 インバータ回路  50 Inverter circuit
60 調光制御回路  60 Dimming control circuit
70 昇圧トランス  70 step-up transformer
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0020] 以下、添付の図面を参照して本発明の放電ランプ点灯装置の実施形態を説明する Hereinafter, embodiments of a discharge lamp lighting device of the present invention will be described with reference to the accompanying drawings.
[0021] 1. 不耍鶴射ノイズの原 の者察 [0021] 1. An insight into the origin of irrational crane noise
最初に、不要輻射ノイズの原因について検討する。  First, the cause of unwanted radiation noise is examined.
本願発明者は、不要輻射ノイズの原因を解明するため鋭意研究をしたところ、放電 ランプに印加される電圧 Vsの周波数を測定する分解能よりも高い分解能で放電ラン プに流れる電流 Iを測定した結果、以下で説明するスパイク状の電流が不要輻射ノィ ズの原因になっていることを新たに発見した。本願発明者は、係るスパイク状の電流 の発見に新たに気づき、この発見を元に本発明に想到するに至った。  The inventor of the present application conducted extensive research to elucidate the cause of unnecessary radiation noise, and as a result, measured the current I flowing through the discharge lamp with a resolution higher than the resolution for measuring the frequency of the voltage Vs applied to the discharge lamp. We have newly discovered that the spike-like current described below is the cause of unwanted radiation noise. The inventor of the present application newly noticed the discovery of the spike-like current, and came to the present invention based on this discovery.
[0022] 図 7は、誘電体バリア放電により発光する放電ランプに印加される高圧の矩形波電 圧 Vsと、流れる電流 Iの波形を模式的に示した図である。図 7 (a)は 100%輝度すな わち全光点灯時の波形、図 7 (b)はバースト調光時の波形を示す。図 7 (a)に示すよ うに全光点灯時には、高電圧の矩形波電圧 Vsの極性が反転するときにほぼ一定形 状のパルス電流が流れる。一方、図 7 (b)に示すバースト調光時には、消灯期間後の 放電ランプ 10が再点灯した時の最初のパルス電流にスパイク状の突入電流 Ispが流 れ、その後、全光点灯時と同等のパルス電流 Ipが流れる(図 7 (b)の拡大図 A参照)。  FIG. 7 is a diagram schematically showing a waveform of a high-pressure rectangular wave voltage Vs applied to a discharge lamp that emits light by dielectric barrier discharge and a flowing current I. Fig. 7 (a) shows 100% luminance, that is, the waveform when all the lights are on, and Fig. 7 (b) shows the waveform when burst dimming. As shown in Fig. 7 (a), when all the lights are on, an almost constant pulse current flows when the polarity of the high-voltage rectangular wave voltage Vs is reversed. On the other hand, during burst dimming shown in Fig. 7 (b), spike-like inrush current Isp flows in the first pulse current when the discharge lamp 10 is turned on again after the extinguishing period, and then it is the same as when all lights are turned on. Pulse current Ip flows (see enlarged view A in Fig. 7 (b)).
[0023] 図 7 (b)に示すスパイク状の突入電流の波高値はパルス電流の波高値の 3〜5倍に もなる場合がある。この現象は、他の冷陰極ランプ等では起こらないか、または起こつ たとしてもここまで大きなスパイク状の突入電流が流れることはない。この現象は、誘 電体バリア放電ランプに印加される電圧が矩形波電圧の場合に生じる、誘電体バリ ァ放電ランプに特有の現象であると考えられる。すなわち、冷陰極ランプは抵抗性負 荷であるが、誘電体バリア放電ランプは容量性負荷であるため、容量性負荷に蓄積 された電荷の放電開始の瞬間にはスパイク状の突入電流が流れやすくなると考えら れる。また、電圧が矩形波であるため、放電ランプに印加される電位が急峻に切り替 わり、スパイク状の突入電流の発生期間(10— 7秒オーダ)は、放電ランプに印加される 電圧の周期(10— 4秒オーダ)。よりも非常に短くノイズとして観測されると推測される。 [0023] The peak value of the spike-like inrush current shown in Fig. 7 (b) may be 3 to 5 times the peak value of the pulse current. This phenomenon does not occur in other cold cathode lamps or the like, or even if it occurs, a large spike-shaped inrush current does not flow so far. This phenomenon occurs when the voltage applied to the dielectric barrier discharge lamp is a rectangular wave voltage. This phenomenon is considered to be peculiar to discharge lamps. In other words, the cold cathode lamp is a resistive load, but the dielectric barrier discharge lamp is a capacitive load. Therefore, a spike-like inrush current tends to flow at the start of discharge of the charge accumulated in the capacitive load. It is considered to be. Further, since the voltage a square wave, the potential is rapidly switched fairly applied to the discharge lamp, the generation period of the spike-like inrush current (10-7 sec order), the period of the voltage applied to the discharge lamp ( 10—on the order of 4 seconds). It is presumed that it will be observed as noise much shorter than that.
[0024] 本発明の発明者は上記の事象に基づき、スパイク状の突入電流が不要輻射ノイズ の一原因であることを見出した。そして、本発明者は不要輻射ノイズを抑制するため にスパイク状の突入電流を抑制すればょ 、と 、う思想に想到し、以下に示す放電ラ ンプ点灯装置を考案した。 The inventor of the present invention has found that spike-like inrush current is one cause of unnecessary radiation noise based on the above-described event. The present inventor has conceived the idea of suppressing spike-like inrush current in order to suppress unnecessary radiation noise, and has devised a discharge lamp lighting device shown below.
[0025] 2. ランプ点、 'rr 置  [0025] 2. Ramp point, 'rr position
図 1は本発明の放電ランプ点灯装置の一実施形態を示すブロック図である。放電ラ ンプ点灯装置は、誘電体バリア放電により発光する放電ランプ 10を駆動する装置で あり、バースト調光機能を有する。  FIG. 1 is a block diagram showing an embodiment of a discharge lamp lighting device of the present invention. The discharge lamp lighting device is a device that drives a discharge lamp 10 that emits light by dielectric barrier discharge, and has a burst dimming function.
[0026] 放電ランプ点灯装置は、直流電源 40と、インバータ回路 50と、調光制御回路 60と [0026] The discharge lamp lighting device includes a DC power supply 40, an inverter circuit 50, a dimming control circuit 60,
、昇圧トランス 70とを含む点灯回路 20を備える。 The lighting circuit 20 including the step-up transformer 70 is provided.
[0027] 特に、放電ランプ点灯装置は、放電ランプ 10へ流入する突入電流を抑制する突入 電流抑制回路 30が点灯回路 20と放電ランプ 10間に直列に接続される。この突入電 流抑制回路 30により放電ランプ 10への突入電流が制限され、不要輻射ノイズが抑 制される。 In particular, in the discharge lamp lighting device, an inrush current suppression circuit 30 that suppresses an inrush current flowing into the discharge lamp 10 is connected in series between the lighting circuit 20 and the discharge lamp 10. The inrush current suppression circuit 30 limits the inrush current to the discharge lamp 10 and suppresses unnecessary radiation noise.
[0028] 図 2に放電ランプ 10の構成の一例を示す。図 2 (a)は側断面図、図 2 (b)は放電ラ ンプ 10の中央部分における軸断面図である。放電ランプ 10は、可視光 (波長: 380η m〜770nm)における透過率が優れたホウケィ酸ガラス、ソーダガラスなどで形成さ れた円筒状の発光管 11に、放電用ガスとしてキセノンを含む混合ガスが封入されて 形成される。その封入圧力は例えば 5〜40kPaの範囲に設定されている。キセノン以 外の混合ガス成分としては、ヘリウム、ネオン、アルゴン、クリプトン等で、混合比を例 えば 6 : 4で混合する。発光管 11の内側表面には蛍光体 15が塗布されている。発光 管 11の一端の内部には、タングステン、ニッケルなどの金属製の内部電極 12が配置 され、リード線 13により、発光管 11の外部に電気的に導出されている。一方、発光管 11の外部には、アルミニウム、銅などの金属製の外部電極 14が配置されている。 FIG. 2 shows an example of the configuration of the discharge lamp 10. FIG. 2 (a) is a side sectional view, and FIG. 2 (b) is an axial sectional view at the central portion of the discharge lamp 10. FIG. The discharge lamp 10 is a mixed gas containing xenon as a discharge gas in a cylindrical arc tube 11 formed of borosilicate glass, soda glass or the like having excellent transmittance in visible light (wavelength: 380 ηm to 770 nm). Is enclosed and formed. The sealing pressure is set in the range of 5 to 40 kPa, for example. The mixed gas components other than xenon are helium, neon, argon, krypton, etc., and the mixing ratio is 6: 4, for example. A phosphor 15 is applied to the inner surface of the arc tube 11. Inside one end of the arc tube 11 is an internal electrode 12 made of metal such as tungsten or nickel. The lead wire 13 is electrically led out of the arc tube 11. On the other hand, an external electrode 14 made of metal such as aluminum or copper is disposed outside the arc tube 11.
[0029] 図 1に戻り、直流電源 40は、平滑整流回路、チヨッパ回路を用いた DC/DCコンパ ータ、直流電圧源 (バッテリ)等で構成され、商用の交流電源電圧を整流して直流電 圧に変換し、インバータ回路 50に出力する。  [0029] Returning to Fig. 1, the DC power supply 40 is configured by a DC / DC converter using a smoothing rectifier circuit, a chopper circuit, a DC voltage source (battery), etc., and rectifies a commercial AC power supply voltage to generate DC power. Pressure and output to the inverter circuit 50.
[0030] インバータ回路 50は矩形波信号生成回路 51と、駆動回路 52と、スイッチング回路 53とで構成される。矩形波信号生成回路 51は所定周波数の矩形波信号 Vpを生成 し、駆動回路 52に出力する。矩形波信号 Vpの周波数は、放電ランプ 10の点灯周波 数を決定し、 10〜: LOOkHzの範囲で設定される。駆動回路 52は、矩形波信号生成 回路 51から入力された矩形波信号 Vpと、調光制御回路 60から入力された調光信号 Vdimとに基づいて、駆動信号 Vdを生成し、スイッチング回路 53へ出力する。スイツ チング回路 53は、直流電源 40に接続されており、駆動回路 52から入力された駆動 信号 Vdに基づいて直流電源 40から供給される直流電圧を矩形波電圧 Vrへ変換し 、変換した矩形波電圧 Vrを昇圧トランス 70の 1次側(1次コイル)に印加する。  The inverter circuit 50 includes a rectangular wave signal generation circuit 51, a drive circuit 52, and a switching circuit 53. The rectangular wave signal generation circuit 51 generates a rectangular wave signal Vp having a predetermined frequency and outputs it to the drive circuit 52. The frequency of the rectangular wave signal Vp determines the lighting frequency of the discharge lamp 10 and is set in the range of 10 to: LOOkHz. The drive circuit 52 generates a drive signal Vd based on the rectangular wave signal Vp input from the rectangular wave signal generation circuit 51 and the dimming signal Vdim input from the dimming control circuit 60, and supplies the driving signal Vd to the switching circuit 53. Output. The switching circuit 53 is connected to the DC power supply 40, converts the DC voltage supplied from the DC power supply 40 to the rectangular wave voltage Vr based on the drive signal Vd input from the drive circuit 52, and converts the converted rectangular wave. Apply voltage Vr to the primary side (primary coil) of step-up transformer 70.
[0031] 昇圧トランス 70は、 1次コイルに印加された矩形波電圧 Vrを高電圧の矩形波電圧 Vsに昇圧して、突入電流抑制回路 30を介して放電ランプ 10の両電極間に印加する 。高圧の矩形波電圧 Vsの電圧値は l〜3kV程度である。  The step-up transformer 70 boosts the rectangular wave voltage Vr applied to the primary coil to a high-voltage rectangular wave voltage Vs and applies it between both electrodes of the discharge lamp 10 via the inrush current suppression circuit 30. . The voltage value of the high-voltage rectangular wave voltage Vs is about 1 to 3 kV.
[0032] 調光制御回路 60は放電ランプ 10に対してバースト調光を行うために、放電ランプ 1 0の発光輝度の上昇 Z下降を指示する指示信号 Sigを受け、指示信号 Sigに応じた 調光信号 Vdimを生成して駆動回路 52へ出力する。指示信号 Sigは外部より入力さ れる例えば 0〜5Vの信号レベルを有する信号であり、その信号レベルが放電ランプ 10の発光輝度の設定値を示すものである。調光信号 Vdimは矩形波信号 Vpの周波 数より低い周波数の PWM信号であり、その周波数は 100〜lkHzに設定される。調 光信号 Vdimのパルス幅は指示信号 Sigに応じて変化する。  [0032] In order to perform burst dimming on the discharge lamp 10, the dimming control circuit 60 receives an instruction signal Sig for instructing an increase in the emission luminance of the discharge lamp 10 and a decrease in Z, and performs dimming according to the instruction signal Sig. An optical signal Vdim is generated and output to the drive circuit 52. The instruction signal Sig is a signal having a signal level of, for example, 0 to 5 V inputted from the outside, and the signal level indicates a set value of the light emission luminance of the discharge lamp 10. The dimming signal Vdim is a PWM signal with a frequency lower than the frequency of the rectangular wave signal Vp, and its frequency is set to 100 to lkHz. The pulse width of the dimming signal Vdim changes according to the instruction signal Sig.
[0033] 突入電流抑制回路 30は誘導性素子で構成される。突入電流抑制回路 30は、バー スト調光時において、消灯期間(OFF)後、放電ランプ 10が再点灯 (ON)した時に放 電ランプ 10に流れる突入電流を抑制し、かつ再点灯した後は、放電ランプ 10に流れ る電流には影響を与えない程度のインピーダンスを有する。例えば、突入電流抑制 回路 30は、測定周波数 100MHzにおけるインピーダンスが 200 Ω以上であることが 望ましい。 [0033] The inrush current suppression circuit 30 is composed of an inductive element. The inrush current suppression circuit 30 suppresses the inrush current that flows through the discharge lamp 10 when the discharge lamp 10 is turned on again after the extinguishing period (OFF) during burst dimming and Thus, it has an impedance that does not affect the current flowing through the discharge lamp 10. For example, inrush current suppression The circuit 30 preferably has an impedance of 200 Ω or more at a measurement frequency of 100 MHz.
[0034] 点灯回路 20の具体構成例を図 3に示す。図 3はプッシュプル方式の点灯回路の構 成を示す。図 4に、図 3の点灯回路 20の各部における電圧波形を示す。以下、図 3、 図 4を用いて点灯回路 20の動作を説明する。  A specific configuration example of the lighting circuit 20 is shown in FIG. Figure 3 shows the configuration of a push-pull lighting circuit. FIG. 4 shows voltage waveforms at various parts of the lighting circuit 20 of FIG. Hereinafter, the operation of the lighting circuit 20 will be described with reference to FIGS.
[0035] 矩形波信号生成回路 51は図 4 (a)に示す所定周波数 (例えば 25kHz)の矩形波 信号 Vpを生成する。矩形波信号生成回路 51は例えばタイマ IC等で構成できる。  The rectangular wave signal generation circuit 51 generates a rectangular wave signal Vp having a predetermined frequency (for example, 25 kHz) shown in FIG. The rectangular wave signal generation circuit 51 can be constituted by a timer IC or the like, for example.
[0036] 駆動回路 52はフリップフロップ回路 54、 AND回路 55、 NOR回路 56より構成され る。フリップフロップ回路 54は矩形波信号生成回路 51からの矩形波信号 Vpがクロッ ク信号として CK端子に入力され、また、調光制御回路 60からの調光信号 Vdimがデ ータ信号として D端子に入力される。フリップフロップ回路 52は、クロック信号 (矩形波 信号 Vp)の立上がりエッジにおけるデータ信号 (調光信号 Vdim)の信号レベルを取 り込み、立上がりエッジ以外では取り込んだ信号レベルを保持し、非反転出力信号 Q と反転出力信号 ZQを出力する。  The drive circuit 52 includes a flip-flop circuit 54, an AND circuit 55, and a NOR circuit 56. In the flip-flop circuit 54, the rectangular wave signal Vp from the rectangular wave signal generation circuit 51 is input to the CK terminal as a clock signal, and the dimming signal Vdim from the dimming control circuit 60 is input to the D terminal as a data signal. Entered. The flip-flop circuit 52 captures the signal level of the data signal (dimming signal Vdim) at the rising edge of the clock signal (rectangular wave signal Vp), holds the captured signal level at other than the rising edge, and outputs a non-inverted output signal. Q and inverted output signal ZQ are output.
[0037] AND回路 55は、フリップフロップ回路 54からの非反転出力信号 Qと、矩形波信号 生成回路 51からの矩形波信号 Vpとを入力し、図 4 (c)に示す駆動信号 Vdlを出力 する。 NOR回路 56は、フリップフロップ回路 54からの反転出力信号 ZQと矩形波信 号生成回路 51からの矩形波信号 Vpとを入力し、図 4 (d)に示す駆動信号 Vd2を出 力する。駆動信号 Vdl、 Vd2はそれぞれ逆極性の信号であり、駆動信号 Vdlがハイ レベルのときは駆動信号 Vd2がローレベル、逆に駆動信号 Vdlがローレベルのとき は駆動信号 Vd2がハイレベルとなる。  [0037] The AND circuit 55 inputs the non-inverted output signal Q from the flip-flop circuit 54 and the rectangular wave signal Vp from the rectangular wave signal generation circuit 51, and outputs the drive signal Vdl shown in Fig. 4 (c). To do. The NOR circuit 56 inputs the inverted output signal ZQ from the flip-flop circuit 54 and the rectangular wave signal Vp from the rectangular wave signal generation circuit 51, and outputs the drive signal Vd2 shown in FIG. 4 (d). The drive signals Vdl and Vd2 are signals having opposite polarities, and when the drive signal Vdl is high level, the drive signal Vd2 is low level. Conversely, when the drive signal Vdl is low level, the drive signal Vd2 is high level.
[0038] スイッチング回路 53は、 FET57、 58とで構成される。 FET57、 58のゲートには、 駆動信号 Vdl,駆動信号 Vd2がそれぞれ入力される。 FET57、 58は駆動信号 Vdl 、 Vd2に応じてそれぞれ交互に ONZOFFし、図 4 (e)、(f)に示す矩形波電圧 Vrl 、 Vr2を昇圧トランス 70の 1次側に印加する。  The switching circuit 53 includes FETs 57 and 58. The drive signals Vdl and Vd2 are input to the gates of the FETs 57 and 58, respectively. The FETs 57 and 58 are alternately turned ON and OFF according to the drive signals Vdl and Vd2, respectively, and the rectangular wave voltages Vrl and Vr2 shown in FIGS. 4 (e) and (f) are applied to the primary side of the step-up transformer 70.
[0039] 調光制御回路 60は三角波発生回路 61、コンパレータ 62とで構成される。三角波 発生回路 61はバースト調光の周波数を決定する例えば 250Hzの三角波信号をコン パレータ 62に出力する。三角波発生回路 61は例えば OPアンプ等で構成できる。コ ンパレータ 62の反転入力には三角波発生回路 61からの三角波信号が入力され、非 反転入力には放電ランプ 10の発光輝度の上昇 Z下降を指示する指示信号 Sigが入 力される。コンパレータ 62は三角波信号と指示信号 Sigを比較し、指示信号 Sigに応 じたノ ルス幅を有する 250Hzの調光信号 Vdimを駆動回路 52に出力する。 The dimming control circuit 60 includes a triangular wave generation circuit 61 and a comparator 62. The triangular wave generation circuit 61 outputs a triangular wave signal of, for example, 250 Hz, which determines the frequency of burst dimming, to the comparator 62. The triangular wave generating circuit 61 can be composed of, for example, an OP amplifier. Co The triangular wave signal from the triangular wave generating circuit 61 is inputted to the inverting input of the comparator 62, and the instruction signal Sig for instructing the increase of the emission luminance Z of the discharge lamp 10 is inputted to the non-inverting input. The comparator 62 compares the triangular wave signal with the instruction signal Sig, and outputs a dimming signal Vdim of 250 Hz having a noise width corresponding to the instruction signal Sig to the drive circuit 52.
[0040] 昇圧トランス 70は、 1次卷線と 2次卷線から構成される。昇圧トランス 70の 1次側に は直流電源 40、スイッチング回路 53の FET57、 58が接続され、 2次側には突入電 流抑制回路 30を介して放電ランプ 10が接続さる。昇圧トランス 70は 1次卷線と 2次卷 線の比で決定される昇圧比に応じて、 1次側に入力される矩形波電圧 Vrl、 Vr2を図 4 (g)に示す高電圧の矩形波電圧 Vs (例えば lkV)に昇圧し、放電ランプ 10に印加 する。 [0040] The step-up transformer 70 is composed of a primary winding and a secondary winding. A DC power supply 40 and FETs 57 and 58 of a switching circuit 53 are connected to the primary side of the step-up transformer 70, and a discharge lamp 10 is connected to the secondary side via an inrush current suppression circuit 30. The step-up transformer 70 uses the rectangular wave voltages Vrl and Vr2 input to the primary side according to the step-up ratio determined by the ratio of the primary and secondary windings to the high voltage rectangle shown in Fig. 4 (g). The voltage is increased to a wave voltage Vs (for example, lkV) and applied to the discharge lamp 10.
[0041] 上記構成において、放電ランプ 10の内部電極 12と外部電極 14間に高電圧の矩 形波電圧 Vsが印加されると、高電圧の矩形波電圧 Vsの電圧値が変化するとき、す なわち極性が反転するときに両電極間にパルス電流が流れ、発光管 11内に誘電体 バリア放電が生じる。このとき発光管 11が誘電体として作用する。誘電体バリア放電 が開始すると、発光管 11内に封入されたキセノンが電子により励起され、紫外線を放 射する。紫外線は発光管 11の内壁に塗布された蛍光体 15により可視光に変換され 、放電ランプ 10が点灯する。一般に、誘電体バリア放電を用いた点灯動作において は、正弦波電圧よりも矩形波電圧で点灯させる。これは、矩形波電圧を用いる方が、 キセノンのエキシマ発光が増加し、紫外線がより多く放出されるため、発光効率がより 良くなるからである。  [0041] In the above configuration, when a high-voltage rectangular wave voltage Vs is applied between the internal electrode 12 and the external electrode 14 of the discharge lamp 10, the voltage value of the high-voltage rectangular wave voltage Vs changes. In other words, when the polarity is reversed, a pulse current flows between both electrodes, and a dielectric barrier discharge is generated in the arc tube 11. At this time, the arc tube 11 acts as a dielectric. When the dielectric barrier discharge starts, xenon sealed in the arc tube 11 is excited by electrons and emits ultraviolet rays. Ultraviolet light is converted into visible light by the phosphor 15 applied to the inner wall of the arc tube 11, and the discharge lamp 10 is turned on. In general, in a lighting operation using dielectric barrier discharge, a rectangular wave voltage is used instead of a sine wave voltage. This is because the xenon excimer emission increases and more ultraviolet rays are emitted when the rectangular wave voltage is used, so that the light emission efficiency is improved.
[0042] スノイク状の突入電流を抑制するために放電ランプ 10と昇圧トランス 70との間に直 列に、突入電流抑制回路 30が接続されている。以下、突入電流抑制回路 30の効果 について説明する。  In order to suppress the snooping inrush current, an inrush current suppression circuit 30 is connected in series between the discharge lamp 10 and the step-up transformer 70. Hereinafter, the effect of the inrush current suppression circuit 30 will be described.
[0043] 不要輻射ノイズ測定を行った結果の一例を以下に示す。測定は、内径 2mm、外形 2. 6mm、長さ 160mmの発光管に 6 :4のキセノン—アルゴン混合ガスを 2 lkPa封入 した放電ランプを 2本使用した液晶用バックライトユニットを用いて、 25kHz、 lkVの 矩形波で点灯して行った。バースト調光の周波数は 250Hzである。突入電流抑制回 路 30としては誘導性素子で測定周波数 100MHzにおけるインピーダンスが 600 Ω のものを放電ランプ 10に直列に接続している。不要輻射ノイズの規定は機器によりさ まざまであるが、ここでは国際電気標準会議 (IEC)の国際無線障害特別委員会 (Int ernational Special Committee on Radio Interference)により疋めりれた測定方法の規 格の 1つである CISPR25に準拠した方法で不要輻射ノイズを測定した。 CISPR25 の方法で測定した結果を表 1に示す。 An example of the result of unnecessary radiation noise measurement is shown below. The measurement was performed at 25 kHz, using a liquid crystal backlight unit using two discharge lamps with 2 lkPa of 6: 4 xenon-argon mixed gas in an arc tube with an inner diameter of 2 mm, an outer diameter of 2.6 mm, and a length of 160 mm. It was lit with a square wave of lkV. The frequency of burst dimming is 250Hz. The inrush current suppression circuit 30 is an inductive element with an impedance of 600 Ω at a measurement frequency of 100 MHz. Are connected to the discharge lamp 10 in series. Unnecessary radiated noise is regulated in various ways depending on the equipment, but here is the standard for measurement methods complied by the International Special Committee on Radio Interference of the International Electrotechnical Commission (IEC). Unwanted radiation noise was measured by a method compliant with CISPR25. Table 1 shows the results measured by the CISPR25 method.
[表 1]  [table 1]
[0044] 表 1は、各周波数帯域での広帯域不要輻射ノイズを測定した結果を示す。なお、通 常 CISPR25〖こお!/、て不要輻射ノイズの規定は 150kHz〜 1GHzの周波数範囲で、 離散的な特定の周波数範囲で不要輻射ノイズの規制があるが、ここでは双円錐アン テナで測定した周波数範囲のみ代表して表示する。 [0044] Table 1 shows the results of measuring broadband unwanted radiation noise in each frequency band. Normally, CISPR25 〖koo! /, The regulation of unwanted radiation noise is in the frequency range of 150kHz to 1GHz, and there is a regulation of unwanted radiation noise in a specific discrete frequency range. Only the measured frequency range is displayed as a representative.
[0045] 表 1から明らかなように、全光点灯時(100%輝度)においては、突入電流抑制回路 30の有無にかかわらずノイズレベルに大きな差は見られない。し力し、調光時(50% 輝度)においては突入電流抑制回路 30を入れることにより 20(1Β /ζ VZm以上もの顕 著な低減が見られる。このとき、パルス状の突入電流を比較すると、波高値がほぼ半 減していた。このことから、このノルス状の突入電流が不要輻射ノイズの一因であると 考えられる。なお、調光点灯時は約 5%輝度の深い調光条件まで、調光度合いを種 々変えながら不要輻射ノイズの測定をしたが、 V、ずれの調光条件にお!、てもほぼ同 様の傾向を示し、不要輻射ノイズの大幅な低減が確認できた。  As is clear from Table 1, when all lights are on (100% luminance), there is no significant difference in noise level regardless of the presence or absence of the inrush current suppression circuit 30. However, during dimming (50% brightness), a significant reduction of 20 (1ζ / ζ VZm or more) can be seen by inserting an inrush current suppression circuit 30. At this time, when comparing the pulsed inrush current, This indicates that the Norse inrush current is considered to be a cause of unnecessary radiation noise, and the dimming condition with about 5% brightness when dimming is on. Until now, unnecessary radiation noise was measured while varying the dimming level.However, even under the dimming conditions of V and deviation, it shows almost the same trend, and it can be confirmed that the unnecessary radiation noise is greatly reduced. It was.
[0046] 次に、突入電流抑制回路 30の誘導性素子のインピーダンス値を変えて不要輻射ノ ィズを測定した結果を表 2に示す。突入電流抑制回路 30のインピーダンス値以外は 、測定サンプル、測定方法ともに表 1の場合と同じである。 [0046] Next, the impedance value of the inductive element of the inrush current suppression circuit 30 is changed to reduce unnecessary radiation noise. Table 2 shows the measurement results. Except for the impedance value of the inrush current suppression circuit 30, the measurement sample and measurement method are the same as in Table 1.
[表 2]  [Table 2]
[0047] 表 2において、突入電流抑制回路 30の測定周波数 100MHzにおけるインピーダ ンスが 100 Ωまでは、ほとんど不要輻射ノイズに顕著な低減効果は見られないが、突 入電流抑制回路 30の測定周波数 100MHzにおけるインピーダンスが 200 Ω以上で は急激に不要輻射ノイズの低減効果が見られた。また、突入電流抑制回路 30の測 定周波数 100MHzにおけるインピーダンスを 2000 Ωとしても、突入電流抑制回路 3 0の測定周波数 100MHzにおけるインピーダンスが 200 Ωの場合と大きな差はなか つた。このことから、 100MHzにおけるインピーダンスが 200 Ω以上であれば、スパイ ク状の突入電流を抑制でき、不要輻射ノイズを低減できると考えられる。 [0047] In Table 2, when the impedance at the measurement frequency of 100 MHz of the inrush current suppression circuit 30 is up to 100 Ω, there is almost no significant reduction effect in unwanted radiation noise, but the measurement frequency of the inrush current suppression circuit 30 is 100 MHz. When the impedance at 200 Ω was 200 Ω or higher, the effect of reducing unwanted radiation noise was abruptly observed. Moreover, even if the impedance at the measurement frequency 100 MHz of the inrush current suppression circuit 30 is 2000 Ω, there is no significant difference from the case where the impedance at the measurement frequency 100 MHz of the inrush current suppression circuit 30 is 200 Ω. Therefore, if the impedance at 100 MHz is 200 Ω or more, it is considered that spike-like inrush current can be suppressed and unnecessary radiation noise can be reduced.
[0048] なお、スパイク状の突入電流を抑制できる 100MHzにおけるインピーダンスの上限 値は、 2000 Ωに限定されない。表 2で示すように、インピーダンスを余り大きくしすぎ ても、不要輻射ノイズの低減効果はあまり期待できないからである。但し、 100MHz におけるインピーダンスが大きすぎると、通常のパルス電流波形にも影響が出てきて 放電哑ランプ 10の発光効率が変わってしまう可能性がある。本願発明者は、種々の 、て測定した結果、突入電流抑制回路 30のインピーダンスは、 測定周波数 100MHzの時の値が 200 Ω以上かつ 22k Ω以下が実用的には望まし いことが判明した。なお、測定は、突入電流抑制回路 30として、 100MHzのときのィ ンピーダンスが 2. 2k Ωの誘導性素子(村田製作所製、品番 BLM21BD222SN1L )を 10個直列に接続して行った。但し、放電ランプ点灯装置における効率や光束値 等に与える影響が実用的に許容範囲内であれば、 100MHzにおけるインピーダン スの上限値は 22k Ωを上回っても差し支えな!/、。 [0048] Note that the upper limit value of impedance at 100 MHz that can suppress spike-like inrush current is not limited to 2000 Ω. As shown in Table 2, the effect of reducing unwanted radiation noise cannot be expected even if the impedance is too high. However, if the impedance at 100 MHz is too large, the normal pulse current waveform may be affected and the luminous efficiency of the discharge lamp 10 may change. The inventor of the present application As a result of the measurement, it was found that the impedance of the inrush current suppression circuit 30 is preferably not less than 200 Ω and not more than 22 kΩ in practice when the measurement frequency is 100 MHz. The measurement was performed by connecting ten inductive elements (product number: BLM21BD222SN1L, manufactured by Murata Manufacturing Co., Ltd.) having an impedance of 2.2 kΩ at 100 MHz as the inrush current suppression circuit 30 in series. However, if the effect on the efficiency and luminous flux value of the discharge lamp lighting device is practically acceptable, the upper limit of the impedance at 100MHz may exceed 22kΩ! /.
[0049] なお、本発明にお!/、て、誘導性素子のインピーダンスの値を 100MHz帯で規定し て 、る理由は、図 7におけるパルス電流に影響を与えずにスパイク状の突入電流を 抑制するためである。放電ランプの点灯周波数帯域 (kHzの帯域。例えば 10kHz以 上 100kHz以下)でインピーダンスを有する突入電流抑制回路 30を挿入した場合、 図 7 (b)におけるパルス電流も抑制してしまい、発光効率や回路効率が低下する。す なわち、本発明では、例えば、特開平 6— 96891号公報が課題としている始動時に 増加したノ ルス電流 (本文献での「尖頭電流」 )を対象として 、るのではなく、パルス 電流よりも遙かに短い時間に発生するスパイク状の電流を対象としてインピーダンス を規定している。以上のように、スパイク状の突入電流の抑制に効果的な周波数帯 域での誘導性素子のインピーダンス値を規定することで、発光効率や回路効率に影 響を与えることなぐスパイク状の突入電流を抑制でき、不要輻射ノイズを効果的に削 減できる。なお、上記のインピーダンス範囲(100MHzの時の値が 200 Ω以上かつ 2 2k Ω以下)を有する誘導性素子は、点灯周波数範囲 (kHzの帯域。例えば 10kHz 以上 100kHz以下)において小さなインピーダンス値となるため、発光効率や回路効 率にほとんど影響がな力つた。 Note that the reason for specifying the impedance value of the inductive element in the 100 MHz band in the present invention is that the spike-like inrush current is not affected by the pulse current in FIG. It is for suppressing. When the inrush current suppression circuit 30 having impedance in the discharge lamp operating frequency band (kHz band, for example, 10 kHz or more and 100 kHz or less) is inserted, the pulse current in FIG. Efficiency is reduced. In other words, in the present invention, for example, the pulse current is not intended for the increased pulse current (starting current in this document), which is the subject of JP-A-6-96891. Impedance is specified for spike-like currents that occur in a much shorter time. As described above, by defining the impedance value of the inductive element in the frequency band that is effective for suppressing spike-like inrush current, spike-like inrush current that does not affect the light emission efficiency or circuit efficiency Can be suppressed, and unnecessary radiation noise can be effectively reduced. An inductive element having the above impedance range (value at 100 MHz is 200 Ω or more and 22 kΩ or less) has a small impedance value in the lighting frequency range (kHz band, for example, 10 kHz or more and 100 kHz or less). This had almost no effect on the luminous efficiency and circuit efficiency.
[0050] 放電ランプの構成に関し、図 2では、放電ランプ 10力 発光管 11の内部に 1つの内 部電極 12と、発光管 11の外部に 1つの外部電極 14とを備える構成を示した力 内部 電極 12が複数配置された形態の希ガス放電灯、外部電極 14が複数配置された形 態の希ガス放電灯であってもよぐ図 2に示した構成に限定されるものではない。  [0050] Regarding the configuration of the discharge lamp, FIG. 2 shows a force that shows a configuration in which one internal electrode 12 is disposed inside the discharge lamp 10 force arc tube 11 and one external electrode 14 is disposed outside the arc tube 11. A rare gas discharge lamp having a plurality of internal electrodes 12 and a rare gas discharge lamp having a plurality of external electrodes 14 are not limited to the configuration shown in FIG.
[0051] 例えば、放電ランプの構成は、図 5 (a)に示す放電ランプ 81のように、内部電極 12 が発光管 11の一端に配置され、かつ複数の外部電極 14a、 14b、 · · · ·、 14hが発光 管 11の外部に配置された構成でもよい。または、図 5 (b)に示す放電ランプ 82のよう に、内部電極 12a、 12bが発光管 11の両端に配置され、かつ 1つの外部電極 14が 発光管 11の外部に配置された構成でもよい。または、図 5 (c)に示す放電ランプ 83 のように、内部電極 12a、 12bが発光管 11の両端に配置され、複数の外部電極 14a 、 14b、 · · · ·、 14hが発光管 11の外部に配置された構成であってもよい。放電ランプ 81、 82、 83の中央部分における軸断面は、図 2 (b)と同様である。また、内部電極 1 2を 3つ以上設けてもよい。 [0051] For example, the configuration of the discharge lamp is such that the internal electrode 12 is disposed at one end of the arc tube 11 and a plurality of external electrodes 14a, 14b, as in the discharge lamp 81 shown in FIG. · 14h emits light A configuration arranged outside the tube 11 may also be used. Alternatively, as in the discharge lamp 82 shown in FIG. 5 (b), the internal electrodes 12a and 12b may be disposed at both ends of the arc tube 11, and one external electrode 14 may be disposed outside the arc tube 11. . Or, like the discharge lamp 83 shown in FIG. 5 (c), the internal electrodes 12a, 12b are arranged at both ends of the arc tube 11, and a plurality of external electrodes 14a, 14b,. The structure arrange | positioned outside may be sufficient. The axial cross section at the center of the discharge lamps 81, 82, 83 is the same as in FIG. 2 (b). Further, three or more internal electrodes 12 may be provided.
[0052] また、放電ランプ 10の外部電極 14の形状についても、発光管 11の外表面に接触 している必要はなぐ発光管 11から離れていてもよいし、図 2に示した平面形状のも のに限定されるものではない。例えば、図 6に示す放電ランプ 84のように、管軸方向 の断面が凹状の外部電極 85が、発光管 11の外部に、発光管 11の円周方向を部分 的に覆うように配置された構成でもよい。また、外部電極 14が発光管 11の外面に螺 旋状に卷回されて配置された構成でもよい。  [0052] Also, the shape of the external electrode 14 of the discharge lamp 10 may be away from the arc tube 11 which does not need to be in contact with the outer surface of the arc tube 11, or may be of the planar shape shown in FIG. It is not limited to anything. For example, like the discharge lamp 84 shown in FIG. 6, the external electrode 85 having a concave cross section in the tube axis direction is disposed outside the arc tube 11 so as to partially cover the circumferential direction of the arc tube 11. It may be configured. Alternatively, the external electrode 14 may be wound around the outer surface of the arc tube 11 in a spiral manner.
[0053] また、発光管 11に封入される放電用ガスはキセノンを含む混合ガスとしたが、混合 ガスでなくてもキセノン 100%のガスであってもよい。  [0053] The discharge gas sealed in the arc tube 11 is a mixed gas containing xenon. However, the discharge gas may not be a mixed gas but may be a gas of 100% xenon.
[0054] また、点灯回路 20はプッシュプル方式と構成の点灯回路で説明したが、他の方式 、例えば、ハーフブリッジ方式、フルブリッジ方式等であってもよい。この場合、昇圧ト ランス 70の構成が変わるのは言うまでもない。  Further, although the lighting circuit 20 has been described with the lighting circuit having the push-pull method and the configuration, other methods such as a half-bridge method and a full-bridge method may be used. In this case, it goes without saying that the configuration of the boosting transformer 70 changes.
[0055] また、矩形波信号生成回路 51、駆動回路 52、調光制御回路 53は他の構成でもよ ぐ例えば 1つのマイコンで構成してもよい。また、外部からの指示信号 Sigとして、直 接外部から PWM信号を入力してもよい。この場合、指示信号 Sigを調光信号 Vdim として、駆動回路 52に入力すればよい。  [0055] The rectangular wave signal generation circuit 51, the drive circuit 52, and the dimming control circuit 53 may have other configurations, for example, a single microcomputer. Further, a PWM signal may be directly input from the outside as the instruction signal Sig from the outside. In this case, the instruction signal Sig may be input to the drive circuit 52 as the dimming signal Vdim.
[0056] また、スイッチング回路 53のスィッチ素子として FET57、 58を用いた力 他のスイツ チ素子でもよぐ例えばバイポーラトランジスタでもよ 、。  [0056] Further, a force using FETs 57 and 58 as a switching element of the switching circuit 53 may be another switching element, for example, a bipolar transistor.
[0057] また、突入電流抑制回路 30以外に、一般的な不要輻射ノイズ対策であるプリント基 板の配線パターンの最適化、シールディング等を組み合わせればさらに不要輻射ノ ィズの低減になることは言うまでもな 、。  [0057] In addition to the inrush current suppression circuit 30, combining the optimization of the printed circuit board wiring pattern, which is a general countermeasure against unnecessary radiation noise, and shielding can further reduce unnecessary radiation noise. Needless to say.
[0058] 本発明は、特定の実施形態について説明されてきたが、当業者にとっては他の多 くの変形例、修正、他の利用が明らかである。それゆえ、本発明は、ここでの特定の 開示に限定されず、添付の請求の範囲によってのみ限定され得る。なお、本出願は 日本国特許出願、特願 2005— 131576号(2005年 4月 28日提出)に関連し、それ らの内容は参照することにより本文中に組み入れられる。 [0058] Although the present invention has been described with respect to particular embodiments, many others will be apparent to those skilled in the art. Many variations, modifications, and other uses are apparent. Accordingly, the invention is not limited to the specific disclosure herein, but can be limited only by the scope of the appended claims. This application is related to Japanese patent application, Japanese Patent Application No. 2005-131576 (submitted on April 28, 2005), the contents of which are incorporated herein by reference.
産業上の利用可能性 Industrial applicability
本発明に係る放電ランプ点灯装置は、様々な用途の光源として用いることが可能で あるが、特に、液晶ディスプレイ等のバックライト、スキャナやコピーの原稿読み取り用 光源等に有用である。  The discharge lamp lighting device according to the present invention can be used as a light source for various purposes, and is particularly useful as a backlight for a liquid crystal display or the like, a light source for reading a document for a scanner or a copy, and the like.

Claims

請求の範囲 The scope of the claims
[1] 誘電体バリア放電によって発光する放電ランプを点灯させる装置であって、  [1] A device for lighting a discharge lamp that emits light by dielectric barrier discharge,
前記放電ランプに矩形波の高周波電圧を印加し、前記放電ランプに点灯期間と消 灯期間を設け、前記点灯期間と前記消灯期間の時間比を変化させることにより調光 点灯を行う点灯回路と、  A lighting circuit that applies dimming lighting by applying a rectangular wave high-frequency voltage to the discharge lamp, providing a lighting period and a lighting period in the discharge lamp, and changing a time ratio between the lighting period and the lighting period;
前記放電ランプと前記点灯回路の間に直列に接続された、測定周波数 100MHz におけるインピーダンス値が 200 Ω以上かつ 22k Ω以下である誘導性素子と 備えたことを特徴とする放電ランプ点灯装置。  A discharge lamp lighting device comprising: an inductive element connected in series between the discharge lamp and the lighting circuit and having an impedance value of 200 Ω or more and 22 kΩ or less at a measurement frequency of 100 MHz.
[2] 前記点灯回路は昇圧トランスを含み、前記放電ランプと前記昇圧トランスの間に直 列に前記誘導性素子を接続することを特徴とする請求項 1記載の放電ランプ点灯装 置。 2. The discharge lamp lighting device according to claim 1, wherein the lighting circuit includes a step-up transformer, and the inductive element is connected in series between the discharge lamp and the step-up transformer.
[3] 前記放電ランプに封入された放電用ガスがキセノンを含み、かつ水銀を実質的に 含まないことを特徴とする請求項 1記載の放電ランプ点灯装置。  3. The discharge lamp lighting device according to claim 1, wherein the discharge gas sealed in the discharge lamp contains xenon and does not substantially contain mercury.
[4] 前記高周波電圧の周波数が 10kHz以上かつ 100kHz以下であることを特徴とする 請求項 1記載の放電ランプ点灯装置。  4. The discharge lamp lighting device according to claim 1, wherein the frequency of the high-frequency voltage is 10 kHz or more and 100 kHz or less.
PCT/JP2006/317518 2006-09-05 2006-09-05 Discharge lamp lighting apparatus WO2008029445A1 (en)

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JP2011120450A (en) * 2009-10-30 2011-06-16 Tdk Corp Wireless power feeder, wireless power transmission system, and table and table lamp using the same
JP2011120451A (en) * 2009-10-28 2011-06-16 Tdk Corp Wireless power feeder, wireless power transmission system, and table and table lamp using the same
US8772977B2 (en) 2010-08-25 2014-07-08 Tdk Corporation Wireless power feeder, wireless power transmission system, and table and table lamp using the same
US8829727B2 (en) 2009-10-30 2014-09-09 Tdk Corporation Wireless power feeder, wireless power transmission system, and table and table lamp using the same
WO2018235307A1 (en) * 2017-06-22 2018-12-27 株式会社東芝 Ozone generation device and power supply for ozone generation device

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* Cited by examiner, † Cited by third party
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JP2011120451A (en) * 2009-10-28 2011-06-16 Tdk Corp Wireless power feeder, wireless power transmission system, and table and table lamp using the same
JP2011120450A (en) * 2009-10-30 2011-06-16 Tdk Corp Wireless power feeder, wireless power transmission system, and table and table lamp using the same
US8829727B2 (en) 2009-10-30 2014-09-09 Tdk Corporation Wireless power feeder, wireless power transmission system, and table and table lamp using the same
US8772977B2 (en) 2010-08-25 2014-07-08 Tdk Corporation Wireless power feeder, wireless power transmission system, and table and table lamp using the same
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JP2019006620A (en) * 2017-06-22 2019-01-17 株式会社東芝 Ozone generation apparatus and power apparatus for ozone generation apparatus

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