JP2005063861A - Electrodeless discharge lamp lighting apparatus and lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrodeless discharge lamp lighting apparatus and a lighting device which can improve the startup performance of an electrodeless discharge lamp when starting up the discharge lamp at a low temperature or at a dark place, with no excessive stress applied to electronic components constituting the lighting device. <P>SOLUTION: A frequency control circuit CN performs control such that after applying a voltage to an induction coil 1b at a first operating frequency f1 at which the electrodeless discharge lamp 1a does not light up during the startup time of the discharge lamp 1a, the frequency is shifted to a second operating frequency f2 that is lower than the first operating frequency f1 to thereby light up the discharge lamp 1a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrodeless discharge lamp lighting device and an illumination device for lighting an electrodeless discharge lamp that emits light by applying a high-frequency electromagnetic field to a bulb in which a discharge gas is sealed.

  A conventional example of this type is disclosed in Japanese Patent Laid-Open No. 10-208894 (hereinafter referred to as Conventional Example 1). In the conventional example 1, as shown in FIG. 8, the control circuit 6J1 gradually changes the output frequency from the variable frequency oscillation circuit OSC2J1 until the electrodeless discharge lamp 1J1 is lit, and this time when the electrodeless discharge lamp 1J1 is lit. The output frequency is changed in the opposite direction to the lighting, and the frequency is returned to the reference frequency f or the vicinity thereof. Thereafter, the switch SJ1 is switched, and a signal having a constant frequency from the frequency fixed oscillation circuit OSC1J1 is applied to the gates of the switching elements Q1J1 and Q2J1 of the amplifier circuit 5J1 via the transformer TJ1, and the electrodeless discharge lamp 1J1 is kept on. In this way, flickering or instability of the electrodeless discharge lamp during frequency switching is prevented.

Another conventional example is disclosed in Japanese Patent Application Laid-Open No. 2001-118695 (hereinafter referred to as Conventional Example 2). In the conventional example 2, the current value at the moment when the switching circuit 8bJ2 of the high frequency power supply circuit 3J2 is turned on or turned off is set so that the input voltage and the input current of the matching circuit 4J2 are in phase as shown in FIG. The oscillation frequency is controlled so that the detection signal becomes zero. By this, the oscillation frequency is controlled so that the input power of the matching circuit 4J2 is constant at the vicinity of the resonance frequency of the load at the start and at the stable lighting. Thus, an electrodeless discharge lamp lighting device excellent in startability and power consumption stability is realized even when the load state varies due to variations in circuit element values.
JP-A-10-208894 JP 2001-118695 A

In the conventional example 1, when the electrodeless discharge lamp 1J1 is started, the output frequency is gradually changed in the increasing direction of the oscillation frequency of the frequency variable oscillation circuit OSC2J1. However, when the ambient temperature of the electrodeless discharge lamp 1J1 is low, the electrodeless discharge lamp 1J1 is started (hereinafter referred to as a low temperature start) or the electrodeless discharge lamp 1J1. However, when the electrodeless discharge lamp 1J1 is to be started (hereinafter referred to as “dark start”), the electrodeless discharge lamp 1J1 may be difficult to start. It was. Further, when the above-described frequency control is performed to start the electrodeless discharge lamp 1J1, excessive stress may be applied to the electronic components that constitute the electrodeless discharge lamp lighting device.

  In the conventional example 2, the oscillation frequency is increased at the start of the electrodeless discharge lamp 1J2, and the resonance frequency is controlled to be a constant value. However, as in the conventional example 1, the low temperature start and the dark place start are performed. In some cases, the electrodeless discharge lamp 1J1 may be difficult to start, and if the resonance frequency is controlled to be a constant value, excessive stress may be applied to the electronic components constituting the electrodeless discharge lamp lighting device.

  The present invention has been made in view of the above problems, and its purpose is to improve the startability of the electrodeless discharge lamp at the low temperature start or dark start of the electrodeless discharge lamp, An object of the present invention is to provide an electrodeless discharge lamp lighting device and an illuminating device in which excessive stress is not applied to electronic components constituting the electrodeless discharge lamp lighting device.

  In order to solve the above-described problem, in the present invention, the frequency control circuit applies a voltage to the induction coil at a first operating frequency at which the electrodeless discharge lamp does not light up during the start-up period of the electrodeless discharge lamp. Control is performed to shift to the second or third operating frequency lower than the operating frequency of 1 and turn on the electrodeless discharge lamp.

In the electrodeless discharge lamp lighting device of the present invention, before the electrodeless discharge lamp normally lights up, a voltage is applied to the induction coil at the first operating frequency at which the electrodeless discharge lamp does not light up, and the electrodeless discharge lamp lights up. Since the starting voltage is applied to the induction coil at the second operating frequency after making it easy to operate, the electrodeless discharge lamp can be normally lit at a relatively low starting voltage, and the electrodeless discharge lamp lighting device It is possible to prevent an excessive stress from being applied to the electronic components constituting the.

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a circuit diagram of the present embodiment, and FIG. 2 shows a cross-sectional view of an electrodeless discharge lamp 1a. FIG. 3 shows a cross-sectional view of the lighting device, and FIG. 4 shows the relationship between the elapsed time t, the operating frequency f, and the applied voltage V02. 5 shows the frequency characteristics of the input impedance of the circuit composed of the inductor L, the capacitor C, and the capacitors C3 and C4. FIG. 6 shows the relationship between other elapsed time t, operating frequency f, and applied voltage V02. Is shown.

  Next, the configuration of each unit will be described.

  The AC power supply AC is a commercial AC power supply, and the voltage is, for example, 100V, 200V, or 240V.

  The rectifier circuit DB rectifies an alternating voltage from the alternating current power supply AC into a pulsating direct current voltage and outputs the pulsating direct current voltage. When the voltage of the AC power supply AC is 100 V, for example, a voltage doubler rectifier circuit may be used instead of the diode bridge. When the voltage doubler rectifier circuit is used, the voltage of the AC power supply AC can be regarded as substantially equal to 200 V, and the current flowing through the circuit connected after the voltage doubler rectifier circuit is about half that when using the diode bridge. As a result, the efficiency of the electrodeless discharge lamp lighting device can be increased.

The chopper circuit converts the pulsating DC voltage from the rectifier circuit DB into a desired DC voltage and outputs it, and controls the operating frequency of the switching element Sc, the diode Dc, the inductor Lc, the capacitor Cc, and the switching element Sc. And a chopper control circuit CNc. Here, the chopper control circuit CNc is composed of, for example, an integrated circuit MC34261 manufactured by Motorola, and controls the operating frequency by connecting the first pin of the integrated circuit to the gate of the switching element Sc. The capacitor Cc smoothes the output voltage of the chopper circuit, and is composed of, for example, an electrolytic capacitor.
In the present embodiment, a boost chopper circuit is used as the chopper circuit. Of course, the chopper circuit may be a step-up / step-down chopper circuit. In short, any circuit configuration may be used as long as it converts a DC voltage into another DC voltage and outputs it.

  The AC power source AC, the rectifier circuit DB, and the chopper circuit constitute a DC power source E.

Next, the power conversion circuit 2 converts the DC voltage from the capacitor Cc into a rectangular wave voltage by alternately turning on and off the switching elements Q1 and Q2 which are the first and second switching elements. And the series circuit of Q2 are connected in parallel with the capacitor Cc. Switching elements Q1 and Q2 are composed of, for example, field effect transistors. In the present embodiment, a so-called half-bridge type inverter circuit is used as the power conversion circuit 2. Of course, the power conversion circuit 2 may be a full bridge type, a single stone type, or a push-pull type.
The inductor L and the capacitor C constitute a series resonance circuit. Due to the resonance operation of the series resonance circuit, a high voltage of several kV is applied to the electrodeless discharge lamp 1a, which will be described later, at the start, and the electrodeless discharge lamp 1a starts lighting.

The matching circuit 3 matches impedance between the power conversion circuit 2 and an induction coil 1b described later, and efficiently transmits high-frequency power from the power conversion circuit 2 to the induction coil 1b. Consists of capacitors C3 and C4.
The electrodeless discharge lamp 1a is disposed close to an induction coil 1b described later and is lit by high-frequency power. Here, the electrodeless discharge lamp 1a will be described in more detail with reference to FIG.
The electrodeless discharge lamp 1a includes a substantially spherical bulb 41 having a hollow portion 45 having a concave cross section, in which a discharge gas containing at least mercury and a rare gas is enclosed, and a discharge disposed in the hollow portion 45. An induction coil 1b for supplying a high-frequency electromagnetic field to gas, a magnetic core around which the induction coil 1b is wound, a cylindrical core 43, and a member of a thermally conductive material that is inside the core 43 and contacts the core 43 42.
The bulb 41 has a substantially spherical shape, in which a discharge gas containing at least mercury and a rare gas is sealed, and a hollow portion having a bottom and a concave cross section is formed on the lower end side of the bulb 41. 45 is provided. The material of the bulb 41 is a translucent material such as quartz glass, and the discharge gas is mercury, a rare gas, and a metal halide. The inside of the bulb 41 is coated with a phosphor 36 and a protective film 37. The phosphor 36 converts ultraviolet rays emitted from mercury into visible light. The phosphor 36 is made of calcium halophosphate, red phosphor (Y, Gd) BO3: Eu, green phosphor. Some CaPO4 and blue phosphor BaMgAll4O23: Eu are used. The protective film 37 improves the luminous flux maintenance factor of the bulb 41 by suppressing the reaction between mercury and quartz glass which is the material of the bulb 41. As a material of the protective film 37, fine particles such as alumina (Al2O3), silica (SiO2), titania (TiO2), ceria (CeO2), yttria (Y2O3), magnesia (MgO), and the like are used. The protective film 37 is preferably formed thinner on the inner surface of the bulb 41 than the phosphor 36 because the normal bulb 41 preferably has a higher transmittance.

  The induction coil 1b supplies a high-frequency electromagnetic field that oscillates at 13.56 MHz to the discharge gas inside the bulb 41. One is wound around a core 43 to be described later, and the other is connected to the matching circuit 3. Yes. In this embodiment, a high frequency electromagnetic field of 13.56 MHz is supplied to the discharge gas. However, if the frequency is about 2.6 MHz to 15 MHz, which can reduce the adverse effects of radiation noise on other electrical devices, even at other frequencies. Good. Here, the induction coil 1b is formed by winding a strip of copper or a copper alloy a predetermined number of times. When the power conversion circuit 2 is operated in the induction coil 1b, a high-frequency current flows, and a high-frequency electromagnetic field is generated around the induction coil 1b. Next, the electrons in the bulb 41 are accelerated by the generated high-frequency electromagnetic field, collide with the atoms of the discharge gas, ionize the discharge gas, and generate new electrons. The electrons generated in this way receive energy by the high-frequency electromagnetic field generated around the induction coil 1b, and collide with the discharge gas atoms to give energy. Atoms in the discharge plasma are ionized and excited. The excited atom emits light when returning to the ground state. This light emission is used as light energy.

  The member 42 has a substantially convex cross section, and is provided so that the core 43 contacts the outside of the convex portion 42 a of the member 42.

  The core 43 has a substantially cylindrical shape and a substantially cylindrical member in which the other end of the core 43 is fixed to the base 48 so that one end of the core 43 faces the center of the valve 41 inside the hollow portion 45. It is provided so as to be in contact with the outer surface of the convex portion 42a of 42. In the present embodiment, nickel zinc (NiZn) phyllite, which is a soft magnetic material having a magnetic permeability of about 150, is used as the material of the core 43. Of course, any material including manganese zinc (Mn—Zn) ferrite and soft magnetic metal may be used. Alternatively, a soft magnetic metal alone may be used. Here, the soft magnetic material has a coercive force Hc in the bulk state of about 10 Oe or less.

The base 48 is a bottomed substantially cylindrical body formed by aluminum die casting and having a top opening. The above-described member 42 is fixed to the bottom of the base 48 so as to face the center of the valve 41. ing. Further, a lid (not shown) is provided at the bottom.
Reference numeral 21 denotes an electrodeless discharge lamp lighting device including a rectifier circuit DB, a chopper circuit, and the like. In the present embodiment, the electrodeless discharge lamp lighting device 21 is housed in the base 48. Of course, the electrodeless discharge lamp lighting device 21 may be provided outside the base 48.
The electrodeless discharge lamp 1a and the electrodeless discharge lamp lighting device 21 constitute an illumination device as shown in FIG. In this lighting device, the upper portion of the bulb 41 can be freely removed, and a shield case 40 that absorbs radiation noise from the electrodeless discharge lamp 1a is covered, and a member 42 is fixed upright on the base 48. . Of course, the lighting device for lighting the electrodeless discharge lamp 1a is not limited to this.

The frequency control circuit CN includes a clock signal generator (not shown) that generates a reference clock signal, and a drive unit (not shown) that receives the reference clock signal and outputs a drive signal to the gates of the switching elements Q1 and Q2. It is configured.
The clock signal generator controls the frequency of the switching elements Q1 and Q2 (hereinafter referred to as the operating frequency) when the electrodeless discharge lamp 1a is started and lit. In this embodiment, NEC Corporation A company-made μPC1934 is used. This μPC 1934 is a low-voltage input 2-output DC-DC converter control IC, and the capacitance value of the capacitor connected to the first pin (not shown) or the resistance value of the resistor connected to the second pin (not shown) is set. The frequency of the reference clock signal output from the 7th pin (not shown) or the 10th pin (not shown) can be changed only by changing. Then, this reference clock signal is input to the drive unit.
The drive unit outputs a drive signal to the gates of the switching elements Q1 and Q2 to alternately turn on and off the switching elements Q1 and Q2 based on the reference clock signal from the clock signal generation unit. In the embodiment, a high voltage half-bridge driver M63991 manufactured by Mitsubishi Electric Corporation is used. When the frequency of the reference clock signal changes, the frequency of the drive signal to the gates of the switching elements Q1 and Q2 changes, and the output of the electrodeless discharge lamp 1a can be changed.
The voltage detection circuit 9 applies the voltage to the induction coil 1b so that the electrodeless discharge lamp 1a does not light up during the start-up period of the electrodeless discharge lamp 1a, and then applies the starting voltage to the induction coil 1b. The voltage between both ends of the induction coil 1b is detected when the transition is made (here, the voltage between both ends of the induction coil 1b is equal to the voltage applied to the electrodeless discharge lamp 1a. Hereinafter, this voltage is referred to as an overvoltage V02. .) That is, the overprint voltage V02 at a level at which the electrodeless discharge lamp 1a does not light is small, but the overprint voltage V02 is also large when the starting voltage is applied to the electrodeless discharge lamp 1a. The voltage detection circuit 9 detects the magnitude of this overvoltage V02.
The voltage detection circuit 9 includes resistors R92 to R94, diodes D92 and D93, capacitors C91 to C95, a Zener diode ZD91, and a transistor Q91. Further, as a voltage detection mode, in the starting state of the electrodeless discharge lamp 1a, since the overvoltage V02 is large, the voltage of the capacitor C92 via the capacitor C94, the diode D92, and the resistor R92 is the ON state of the zener diode ZD91. When the voltage exceeds the ON voltage of the Zener diode ZD91 in this way, the transistor Q91 is turned ON and a low signal is input to the frequency switching means CNf. On the contrary, in the weak discharge state of the electrodeless discharge lamp 1a, since the overvoltage V02 is small, the voltage of the capacitor C92 cannot reach the ON voltage of the Zener diode ZD91, and a high signal is input to the frequency switching means CNf. The
In the present embodiment, one end of the capacitor C94 is connected to one end of the induction coil 1b. However, the point where the one end of the capacitor C94 is connected may be a connection point between the capacitors C1 and C2. In short, as long as the voltage is proportional or reflected to the overprint voltage V02, the voltage at any point may be detected.
The frequency switching means CNf receives the detection signal from the voltage detection circuit 9 and detects that the electrodeless discharge lamp 1a has shifted to the weak discharge state, and the frequency signal of the reference clock signal is sent to the clock signal generation unit of the frequency control circuit CN. A change signal is transmitted. In this embodiment, a microcomputer provided with an arithmetic circuit (CPU) constituted by a microprocessor or the like, a memory, and an interface circuit is used. The ST72G series manufactured by STMicroelectronics is used as this type of microcomputer. When such a microcomputer is used, the above-described control can be performed simply by setting a program.

Next, the operation of the present embodiment will be described with reference to FIGS.
When the AC power supply AC is turned on at t = 0, power is supplied to the chopper control circuit CNc, the frequency control circuit CN, and the frequency switching means CNf to start the operation, and the starting period of the electrodeless discharge lamp 1a starts. Then, according to the first reference clock signal from the frequency switching means CNf, the operating frequency of the switching elements Q1 and Q2 is the first operation for applying the overvoltage V02 to the induction coil 1b to such an extent that the electrodeless discharge lamp 1a is not lit. The operation starts at the frequency f1. At the same time as the switching elements Q1 and Q2 operate, the capacitor C92 is charged via the diode D92 and the resistor R92, using the divided voltage of the capacitors C94 and C95 as a power source. When the voltage of the capacitor C93 exceeds the ON voltage of the Zener diode ZD91, the transistor Q91 is turned ON, and a low signal is input to the frequency switching means CNf.
By the way, before the electrodeless discharge lamp 1a is turned on, if a voltage that does not light the electrodeless discharge lamp 1a is applied to the induction coil 1b, the high frequency electromagnetic field from the induction coil 1b causes the inside of the bulb 41 to be turned on. Energy is given to the free electrons. At this time, even if an impurity gas (for example, HI) generated by a halide such as iodide brought into the bulb 41 attempts to capture the free electrons, the free electrons activated by being given energy. Is not captured by the impure gas, and the valve 41 is in a state where there are many free electrons. If a starting voltage is applied to the electrodeless discharge lamp 1a in this state, the startability is improved. Further, due to the high frequency electromagnetic field from the induction coil 1b, the ionization of mercury or a rare gas occurs to some extent, and the number of free electrons in the bulb 41 is further increased. Furthermore, it is considered that impure gas molecules such as HI may be dissociated by the high frequency electromagnetic field from the induction coil 1b. The dissociated impure gas molecules are likely to adhere to the tube wall of the bulb 41, and therefore the amount of impure gas in the discharge space is reduced. Due to the above reasons, if a voltage that does not light the electrodeless discharge lamp 1a is applied to the induction coil 1b before the electrodeless discharge lamp 1a is turned on, the startability of the electrodeless discharge lamp 1a is improved. Can be improved.
Next, when a low signal is input to the frequency switching means CNf at t = t1, the frequency switching means CNf is discrete from the first reference clock frequency to the second reference clock frequency lower than the first reference clock frequency. Start to change. In response to the change in the reference clock signal from the frequency switching means CNf, the frequency control circuit CN changes the operating frequency of the switching elements Q1 and Q2 from the first operating frequency f1 to the first as shown in FIG. To the second operating frequency f2 lower than the operating frequency f1. At this time, since the operating frequency is lowered, the applied voltage V02 is increased as shown in FIG.
Here, a setting condition of the second operating frequency f2 is considered. FIG. 5 shows the frequency characteristics of the input impedance of a circuit composed of the inductor L, the capacitor C, and the capacitors C3 and C4. | Z | represents the absolute value of the input impedance, and θ represents the phase angle of the input impedance. As can be seen from FIG. 5, there are three resonance frequencies at which θ = 0. Let the lowest resonance frequency be F0, the second highest resonance frequency, and f0 the highest resonance frequency. When a half-bridge type inverter circuit is used as the power conversion circuit 2 as in the present embodiment, when the impedance of the electrodeless discharge lamp 1a viewed from the power conversion circuit 2 becomes capacitive, the switching elements Q1 and Q2 At the same time, a large current flows from the AC power supply AC, and an excessive stress may be applied to the components constituting the electrodeless discharge lamp lighting device.
In order to avoid such a case, the impedance of the electrodeless discharge lamp 1a viewed from the power conversion circuit 2 must be inductive (θ> 0) or resistive (θ = 0). In the case of the input impedance shown in FIG. 5, the frequency f at which the impedance becomes capacitive is F0 <f <f0. That is, when the second operating frequency f2> resonance frequency f0 is set, the impedance does not become capacitive.
Next, when the electrodeless discharge lamp 1a is lit at t = t2, the operating point of the electrodeless discharge lamp lighting device shifts from the no-load resonance curve shown in FIG. 5 to the resonance curve at the time of lighting. The voltage V02 applied to 1a is smaller than the applied voltage V02 in the period (t2-t1).
Finally, at t = t3, the operating frequency is adjusted by the frequency control circuit CN so that the electrodeless discharge lamp 1a is rated-lit. In FIG. 5, the operating frequency f2 at t = t2 and the operating frequency f2 at t = t3 are equal, but they may not be equal. For example, although not shown, a circuit for detecting the current flowing through the induction coil 1b, the voltage applied to the induction coil 1b, and the phase difference between them is provided separately in FIG. 1, and the period shown in FIG. At (t4-t3), the electric power of the electrodeless discharge lamp 1a is measured. Then, the rated power of the electrodeless discharge lamp 1a preliminarily stored in the memory of the frequency control circuit CN may be compared, and the operating frequency may be appropriately controlled so that they match after t = t4. After the electrodeless discharge lamp 1a is lit in this way, when the power of the electrodeless discharge lamp 1a is measured again and the power of the electrodeless discharge lamp 1a is readjusted, each electronic component constituting the electrodeless discharge lamp lighting device varies. Even in this case, the electrodeless discharge lamp 1a can always be lit at the rated power.

  Here, a secondary winding may be provided in the inductor L, the number of turns of the secondary winding may be set as appropriate, and a voltage generated in the secondary winding may be directly input to the frequency switching means CNf. In this way, it is not necessary to provide the voltage detection circuit 9 that detects the high voltage generated at both ends of the induction coil 1b. Furthermore, the wiring length of the signal input to the frequency switching means CNf can be shortened, and noise due to the wiring can be suppressed.

If a timer circuit is separately provided, or a timer function is added to the frequency switching means CNf having a microcomputer function by programming, and the electrodeless discharge lamp 1a does not light even if the frequency change is repeated for a certain period of time, the electrodeless discharge is not performed. The electric power lighting device may be regarded as being in an abnormal state and the power conversion circuit 2 or the chopper circuit may be stopped. Further, without using the timer circuit, the frequency variable frequency may be counted, and the power conversion circuit 2 or the chopper circuit may be stopped when the frequency change frequency reaches a certain frequency.
Furthermore, in the present embodiment, only the frequency switching means CNf is microcomputerized, but of course, the chopper control circuit CNc, frequency control circuit CN and voltage detection circuit 9 may all be microcomputerized. Thus, if all the control circuits are made into microcomputers, the electrodeless discharge lamp lighting device can be made compact.
Note that if the operating frequency is less than several tens of kHz, the loss in the induction coil 1b becomes very large and it becomes difficult to maintain lighting, which is not practical. Further, when the operating frequency is several tens of MHz or more, not only the loss of the power conversion circuit 2 and the like increases, but also the copper loss due to the winding of the induction coil 1b becomes very large due to the skin effect, and the luminous efficiency is lowered. . Therefore, the operating frequency is preferably several tens of kHz to several tens of MHz. Further, depending on the type of the electrodeless discharge lamp 1a, the operating frequency for outputting the rated power of the electrodeless discharge lamp 1a may be the second operating frequency f2, but the second operating frequency f2 is set to 150 kHz or less. If set, noise countermeasures in the Electrical Appliance and Material Safety Law may be facilitated, and it is desirable to set the operating frequency when the electrodeless discharge lamp 1a is turned on to 150 kHz or less in consideration of noise countermeasures.

  As described above, according to the present embodiment, before the electrodeless discharge lamp 1a is normally lit, the electrodeless discharge lamp 1a is weakly discharged at the first operating frequency f1 so that the electrodeless discharge lamp 1a is easily lit. Later, since the starting voltage is applied to the electrodeless discharge lamp 1a, the electrodeless discharge lamp 1a can be normally lit with a relatively low starting voltage, and the electronic components constituting the electrodeless discharge lamp lighting device are excessively charged. It can prevent stress. Further, it is possible to improve startability when the ambient temperature of the electrodeless discharge lamp 1a is low or when starting in a dark place.

(Second Embodiment)
The second embodiment of the present invention will be described below with reference to FIG. FIG. 7 shows the relationship between the elapsed time t, the operating frequency f, and the applied voltage V02. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the present embodiment, as shown in FIG. 7, a voltage is applied to the induction coil 1b at the first operating frequency f1 until t = t1, and the operating frequency is set to the first operating frequency f1 at t = t1. The third operating frequency f3 is discretely shifted to a lower operating frequency f2 than the second operating frequency f2. Thereafter, during the period (t2-t1), the third operating frequency f3 is continuously shifted to the second operating frequency f2, and the electrodeless discharge lamp 1a is turned on.

  As described above, before the electrodeless discharge lamp 1a is normally lit, the electrodeless discharge lamp 1a is weakly discharged at the first operating frequency f1 so that the electrodeless discharge lamp 1a is easily lit. By lowering the operating frequency at t1), that is, by increasing the applied voltage V02, the electrodeless discharge lamp 1a can be normally lit more reliably than in the first embodiment, and the electrodeless discharge can be performed. The startability when the ambient temperature of the electric lamp 1a is low or when starting in a dark place can be improved.

  Note that the operations and effects not particularly mentioned in the present embodiment are the same as those in the first embodiment.

1 is a circuit diagram showing a first embodiment. FIG. It is sectional drawing of an electrodeless discharge lamp. It is sectional drawing of an illuminating device. It is a characteristic view which shows the relationship between the elapsed time t, the operating frequency f, and the applied voltage V02. It is a figure which shows the frequency characteristic of input impedance. It is a characteristic view which shows the relationship between other elapsed time t, the operating frequency f, and the applied voltage V02. In 2nd Embodiment, it is a characteristic view which shows the relationship between the elapsed time t, the operating frequency f, and the applied voltage V02. It is a circuit diagram which shows a 1st prior art example. It is a circuit diagram which shows a 2nd prior art example.

Explanation of symbols

E DC power supply Q1 First switching element Q2 Second switching element 2 Power conversion circuit 3 Matching circuit 1b Inductive coil 1a Electrodeless discharge lamp CN Frequency control circuit f1 First operating frequency f2 Second operating frequency f3 Third Operating frequency 45 Cavity 41 Valve 43 Core 42 Member

Claims (6)

DC power supply, power conversion circuit having first and second switching elements that convert DC power supply to high-frequency power and alternately turn on / off, matching circuit that matches high-frequency power from power conversion circuit, and matching circuit An induction coil to which high-frequency power from is applied, an electrodeless discharge lamp that is disposed in proximity to the induction coil and is lit by high-frequency power, and a frequency control circuit that controls the operating frequency of the first and second switching elements. The second operating frequency lower than the first operating frequency after applying a voltage to the induction coil at the first operating frequency at which the electrodeless discharge lamp does not light up during the starting period of the electrodeless discharge lamp by the frequency control circuit The electrodeless discharge lamp lighting device is characterized in that it controls to turn on the electrodeless discharge lamp. After a voltage is applied to the induction coil at the first operating frequency, a transition is made to a third operating frequency that is lower than the first operating frequency and higher than the second operating frequency, and from the third operating frequency to the second operating frequency. The electrodeless discharge lamp lighting device according to claim 1, wherein control is performed to continuously shift to an operating frequency and turn on the electrodeless discharge lamp. 3. The electrodeless discharge lamp lighting device according to claim 1, wherein an operating frequency is controlled by a frequency control circuit so that the electrodeless discharge lamp is rated-lit after the electrodeless discharge lamp is turned on. 4. The electrodeless electrode according to claim 1, wherein the first operating frequency is greater than 150 kHz and several tens of MHz or less, and the second operating frequency is greater than several tens kHz and 150 kHz or less. 5. Discharge lamp lighting device. An electrodeless discharge lamp includes a substantially spherical bulb having a hollow portion with a concave cross section in which a discharge gas containing at least mercury and a rare gas is enclosed, and a high-frequency electromagnetic field disposed in the hollow portion. An induction coil to be supplied; a cylindrical core made of a magnetic material around which the induction coil is wound; and a member made of a heat conductive material that is inside the core and contacts the core. The electrodeless discharge lamp lighting device according to any one of claims 1 to 4. An illuminating device comprising the electrodeless discharge lamp lighting device according to any one of claims 1 to 5.

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