JP2010009859A - Electrodeless discharge lamp lighting device and lighting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrodeless discharge lamp lighting device capable of reducing an electric stress applied to a circuit component at the time of staring. <P>SOLUTION: There are provided an induction coil that is placed closely to the electrodeless discharge lamp, a direct current power supply circuit that outputs a direct current power, and an inverter circuit that converts the direct current power output from the direct current power supply circuit into an alternating-current power to be supplied to the induction coil. Just after the staring of the electrodeless discharge lamp, the inverter circuit slowly decreases an operating frequency f from an initial value f3 to a constant value f2 so that the amplitude of an output voltage Vx to the induction coil is slowly increased. At the time of staring, the electric stress applied to the circuit component when the inverter circuit starts the output of the voltage Vx to the induction coil is reduced in comparison with the case where the operating frequency f is set to the constant value f2 just after staring. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrodeless discharge lamp lighting device and a lighting fixture using the electrodeless discharge lamp lighting device.

Conventionally, an electrodeless discharge lamp lighting device for lighting an electrodeless discharge lamp in which a discharge gas is sealed in a bulb made of a light-transmitting material such as glass has been provided (for example, Patent Document 1 and Patent Document 2). This type of electrodeless discharge lamp lighting device includes an induction coil disposed close to the electrodeless discharge lamp, and a power supply unit that supplies high-frequency power to the induction coil. An electromagnetic field is generated. When an arc discharge is generated in the bulb of the electrodeless discharge lamp by the high frequency electromagnetic field, the excited discharge gas emits ultraviolet rays. A fluorescent material is applied to the inner surface of the bulb of the electrodeless discharge lamp, and the ultraviolet light is converted into visible light by the fluorescent material, whereby the electrodeless discharge lamp emits light.
JP 2005-158464 A Japanese Patent Laid-Open No. 2005-158459

  Conventionally, when the electrodeless discharge lamp is started, the frequency of the AC power output from the inverter circuit to the induction coil is kept constant for a predetermined period immediately after the start of the output of AC power from the inverter circuit to the induction coil. .

  However, if the frequency of the AC power output from the inverter circuit to the induction coil is the frequency that should be kept constant as described above immediately after the start of the output of AC power from the inverter circuit to the induction coil, Relatively large electrical stress is easily applied.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide an electrodeless discharge lamp lighting device capable of reducing electrical stress applied to circuit components at the time of starting.

  The invention of claim 1 includes an induction coil disposed in proximity to the electrodeless discharge lamp, a power supply circuit that supplies AC power to the induction coil, and a control circuit that controls the power supply circuit, and at the time of starting the electrodeless discharge lamp. Immediately after the output of AC power from the power supply circuit to the induction coil is started, the control circuit gradually increases the power output from the power supply circuit to the induction coil.

  According to the present invention, compared with the case where the power output from the power supply circuit to the induction coil is the increased power immediately after the start, the electrical stress applied to the circuit components at the start is reduced.

  According to a second aspect of the present invention, in the first aspect of the present invention, when the electrodeless discharge lamp is started, the control circuit before the power supplied to the induction coil becomes high enough to cause arc discharge in the electrodeless discharge lamp. The start preparation operation for controlling the power supply circuit is performed so as to maintain the electric power supplied to the induction coil so low that arc discharge does not occur in the electrodeless discharge lamp for a predetermined time.

  According to the present invention, compared with the case where the start preparation operation is not performed, since the change in the characteristics of the load circuit composed of the induction coil and the electrodeless discharge lamp becomes gentle at the start, the DC power supply circuit and the inverter circuit Output is stable.

  According to a third aspect of the present invention, in the second aspect of the present invention, the control circuit includes a voltage detection circuit that outputs a detection voltage that is a DC voltage having a higher voltage value as the amplitude of the voltage output from the power supply circuit to the induction coil increases. Is characterized by performing feedback control for maintaining the output power of the power supply circuit constant based on the detection voltage output by the voltage detection circuit during the start preparation operation.

  According to this invention, compared with the case where feedback control is not performed, the influence of the dispersion | variation in the characteristic of a circuit component and ambient temperature is suppressed.

  Invention of Claim 4 is the electrodeless discharge lamp lighting device of any one of Claims 1-3, the electrodeless discharge lamp and electrodeless discharge lamp lighting device which are lighted by an electrodeless discharge lamp lighting device, And an instrument main body for holding each.

  According to the first aspect of the present invention, at the start of the electrodeless discharge lamp, immediately after the output of AC power from the power supply circuit to the induction coil is started, the control circuit outputs the power output from the power supply circuit to the induction coil. Therefore, the electrical stress applied to the circuit components at the time of starting is reduced as compared with the case where the power output from the power supply circuit to the induction coil is set to the increased power immediately after starting.

  According to the invention of claim 2, when the electrodeless discharge lamp is started, the control circuit supplies the induction coil before the power supplied to the induction coil becomes high enough to cause arc discharge in the electrodeless discharge lamp. The power supply circuit is controlled so that the generated power is kept low enough to prevent arc discharge in the electrodeless discharge lamp for a predetermined time. At times, since the change in the characteristics of the load circuit composed of the induction coil and the electrodeless discharge lamp becomes gradual, the outputs of the DC power supply circuit and the inverter circuit are stabilized.

  According to the invention of claim 3, the control circuit is provided with a voltage detection circuit that outputs a detection voltage that is a DC voltage having a higher voltage value as the amplitude of the voltage output from the power supply circuit to the induction coil is larger. The feedback control that maintains the output power of the power supply circuit at a constant level is performed based on the detection voltage output from the voltage detection circuit. Is suppressed.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
In the present embodiment, as shown in FIG. 2, an induction coil 5 disposed close to an electrodeless discharge lamp, a DC power supply circuit 1 that converts AC power supplied from an AC power supply AC into DC power, and a DC power supply circuit The inverter circuit 2 as a power supply circuit that converts the DC power output from 1 into high-frequency AC power and outputs it to the induction coil 5, and the voltage that the inverter circuit 2 outputs to the induction coil 5 (hereinafter referred to as "coil voltage"). .) A voltage detection circuit 4 that outputs a detection voltage Vxs that is a DC voltage having a higher voltage value as the amplitude of Vx increases, and a control circuit 3 that controls the inverter circuit 2 based on the detection voltage Vxs output by the voltage detection circuit 4 With.

  The induction coil 5 is wound around a cylindrical coupler 50 as shown in FIG. In the example of FIG. 3, the electrodeless discharge lamp lighting device of the present embodiment is housed in a metal case 10 and is electrically connected to the induction coil 5 through a feeder 10 a.

  As shown in FIG. 4, the electrodeless discharge lamp 6 includes a hollow bulb 61 made of a transparent material such as glass and having a recess 60 on the outer surface, and a cylindrical shape made of synthetic resin. And a base 62 attached so as to surround the opening of 60. The coupler 50 is inserted into the recess 60 and is disposed in the vicinity of the induction coil 5. For example, a discharge gas containing an inert gas and metal vapor is sealed in the bulb 61. Further, a convex portion 61 a that is inserted into the coupler 50 protrudes from the bottom surface of the concave portion 60 of the bulb 61. Further, a protective film 62 and a phosphor film 63 are provided on the inner surface of the bulb 61. That is, when arc discharge is generated in the bulb 61 by the high-frequency electromagnetic field generated by the induction coil 5, the generated ultraviolet light is converted into visible light in the phosphor film 63, so that the electrodeless discharge lamp 6 emits light.

  The DC power supply circuit 1 includes a diode bridge DB that full-wave rectifies an AC current supplied from an AC power supply AC, and a series circuit of an inductor L0, a diode D0, and an output capacitor C0 connected between the output terminals of the diode bridge DB. The switching element Q0 connected between the connection point of the inductor L0 and the diode D0 and the output terminal on the low voltage side of the diode bridge DB and the voltage across the output capacitor C0 (that is, the output voltage of the DC power supply circuit 1 below). And a voltage control unit 11 that drives the switching element Q0 on and off with a duty ratio such that Vdc is a constant steady voltage Vs (see FIG. 1). Converter).

  The inverter circuit 2 has one end at the connection point between the switching elements Q1 and Q2 and the series circuit of the switching elements Q1 and Q2 and the detection resistor Rd connected between the output ends of the DC power supply circuit 1, that is, between both ends of the output capacitor C0. The connected inductor Ls, a series capacitor Cs having one end connected to the other end of the inductor Ls and the other end connected to one end of the induction coil 5, and one end connected to a connection point between the inductor Ls and the series capacitor Cs. A parallel capacitor Cs whose other end is connected to a connection point between the detection resistor Rd and the induction coil 5 and a drive unit 21 for alternately turning on and off the switching elements Q1 and Q2 are provided. That is, the switching elements Q1 and Q2 are alternately turned on and off to switch the connection between the resonance circuit formed by the inductor Ls, the series capacitor Cs, the parallel capacitor Cs, and the induction coil 5 and the DC power supply circuit 1, and this resonance. Due to the resonance of the circuit, the DC power output from the DC power supply circuit 1 is converted into high-frequency AC power and supplied to the induction coil 5. The switching elements Q1 and Q2 are each composed of an N-channel FET, and the drive unit 21 outputs a rectangular wave driving signal to the gates of the switching elements Q1 and Q2, respectively. Q2 is driven on and off, respectively. Furthermore, the drive unit 21 has a control terminal CON, and the higher the control current Io flowing out from the control terminal CON, the higher the frequency (hereinafter referred to as “operation frequency”) f at which the switching elements Q1 and Q2 are turned on / off. To do. Normally, as shown in FIG. 5, the operating frequency f is in a range higher than the resonance frequency (hereinafter simply referred to as “resonance frequency”) f0 of the above-described resonance circuit, and the control current Io is reduced. As the operating frequency f decreases, the amplitude of the coil voltage Vx increases and the power supplied from the inverter circuit 2 to the induction coil 5 increases. In FIG. 5, the upper curve A shows the relationship between the amplitude | Vx | of the coil voltage Vx and the operating frequency f when the DC voltage Vdc is the steady voltage Vs and the electrodeless discharge lamp 6 is turned off. The lower curve B shows the relationship between the amplitude | Vx | of the coil voltage Vx and the operating frequency f when the DC voltage Vdc is the steady voltage Vs and the electrodeless discharge lamp 6 is lit. ing.

  The voltage detection circuit 4 includes a rectifying diode, a voltage dividing resistor, and a smoothing capacitor, and outputs a detection voltage Vxs that is a DC voltage having a higher voltage value as the amplitude of the coil voltage Vx increases.

  The control circuit 3 also includes a sweep circuit 31 that performs a sweep operation that gradually increases the output power from the inverter circuit 2 to the induction coil 5 by gradually decreasing the operating frequency f when the electrodeless discharge lamp 6 is started. .

  The sweep circuit 31 includes an operational amplifier OP1 having an inverting input terminal connected to the output terminal via the feedback resistor R3 and connected to the output terminal of the voltage detection circuit 4 via the input resistor R4. The output terminal of the operational amplifier OP1 is connected to the control terminal CON of the drive unit 21 via a series circuit of a backflow prevention diode D1 and an output resistor R5. The sweep circuit 31 includes a series circuit of a resistor R1 and a resistor R11, each having a constant voltage Vd input thereto, and one end connected to the other end of the series circuit (one end of the resistor R11) and the other end connected to the circuit ground. And a parallel circuit of a resistor R2 and a capacitor C1, and a non-inverting input terminal of the operational amplifier OP1 has two resistors R1 and R11 constituting the series circuit. Connected to the connection point. In the sweep circuit 31 of the present embodiment, since the inverting input terminal of the operational amplifier OP1 is connected to the output terminal of the voltage detection circuit 4 via the input resistor R4 as described above, the larger the amplitude of the coil voltage Vx, that is, the inverter The more power supplied from the circuit 2 to the induction coil 5, the lower the output voltage of the operational amplifier OP1 and the current flowing from the control terminal CON of the drive unit 21 into the sweep circuit 31 (hereinafter referred to as “sweep current”). As Isw increases and the operating frequency f increases, the power supplied from the inverter circuit 2 to the induction coil 5 decreases. That is, the sweep circuit 31 also performs a feedback operation using the detection voltage Vxs output from the voltage detection circuit 4. Further, in the sweep circuit 31, when considering the operation in a state in which the voltage across the capacitor C1 is stable, the non-inversion of the operational amplifier OP1 is greater when the switch SW is on than when the switch SW is off. Since the input voltage Vc1 to the input terminal is lowered, the output voltage of the operational amplifier OP1 is lowered, the sweep current Isw is increased, and the operating frequency f is increased, the power supplied from the inverter circuit 2 to the induction coil 5 is reduced. When the switch SW is switched from on to off, the output voltage of the operational amplifier OP1 gradually increases and the sweep current Isw gradually decreases due to the time constant of the circuit formed by the resistors R1 and R2 and the capacitor C1. Thus, a sweep operation is performed in which the operating frequency f is gradually lowered and the power supplied from the inverter circuit 2 to the induction coil 5 is gradually increased.

  The control circuit 3 includes a feedback circuit 32 that controls the operating frequency f based on the voltage at the connection point between the low-side switching element Q2 and the detection resistor Rd in the inverter circuit 2, that is, the current flowing through the inverter circuit 2. The feedback circuit 32 includes an operational amplifier OP2 in which a predetermined reference voltage Vr1 is input to a non-inverting input terminal and an output terminal is connected to a control terminal CON of the drive unit 21 via a diode D2 and an input resistor R6. The inverting input terminal of the operational amplifier OP2 is connected to the output terminal of the operational amplifier OP2 through a parallel circuit of the resistor R7 and the capacitor C2, and is connected to a connection point between the switching element Q2 and the detection resistor Rd through the resistor R8. ing. That is, the current (hereinafter referred to as “feedback current”) Ifb flowing from the control terminal CON of the drive unit 21 into the feedback circuit 32 increases as the current flowing through the induction coil 5 increases (that is, the power supplied to the induction coil 5). The higher the frequency, the more the power supplied to the induction coil 5 decreases, and the feedback circuit 32 operates so that the power supplied from the inverter circuit 2 to the induction coil 5 is kept constant. Each of the sweep circuit 31 and the feedback circuit 32 has an operating frequency f in the state where the switch SW is turned off in the sweep circuit 31 and the voltage across the capacitor C1 is stable. Electric power sufficient to generate electromagnetic field discharge or inductively coupled discharge) is a lighting frequency f1 (see FIG. 5) that is supplied from the inverter circuit 2 to the induction coil 5 and is switched in the sweep circuit 31. In a state where the SW is turned on and the voltage across the capacitor C1 is stable, the operating frequency f is such that E discharge (glow discharge, also called high frequency electric field discharge or capacitively coupled discharge) occurs in the electrodeless discharge lamp 6. Designed to have a turn-off frequency f2 such that power is supplied from the inverter circuit 2 to the induction coil 5. To have. Due to the feedback of the sweep circuit 31 and the feedback circuit 32, the operating frequency f is lowered when the DC voltage Vdc is lower than the steady voltage Vs, and conversely when the DC voltage Vdc is higher than the steady voltage Vs. The operating frequency f is set higher than the above. That is, the target value of the power supplied to the induction coil 5 (the amplitude of the coil voltage Vx) is H in the electrodeless discharge lamp 6 when the switch SW is turned off in the sweep circuit 31 and the voltage across the capacitor C1 is stable. When the switch SW is turned on in the sweep circuit 31 and the voltage across the capacitor C1 is stable, the electrodeless discharge lamp 6 does not generate H discharge and E discharge occurs. The In FIG. 5, the voltage Vx1 indicates the amplitude | Vx | of the coil voltage Vx at which the H discharge (arc discharge) is generated in the electrodeless discharge lamp 6.

  Hereinafter, the operation of the present embodiment will be described with reference to FIG. Each of the four graphs in FIG. 1 has time t as the horizontal axis, and the top graph shows the absolute value of the input voltage from the AC power supply AC (ie, the output voltage of the diode bridge DB. Hereinafter, simply referred to as “input voltage”). ) Vin is the vertical axis, the second graph from the top is the output voltage Vdc of the DC power supply circuit 1 is the vertical axis, the third graph from the top is the operating frequency f of the inverter circuit 2 is the vertical axis, and the bottom In the graph, the vertical axis represents the coil voltage Vx.

  Here, the voltage control unit 11 of the DC power supply circuit 1 and the drive unit 21 of the inverter circuit 2 are connected to the other ends of capacitors Cc and Ci each having one end connected to the ground. The voltage control unit 11 and the drive unit 21 monitor the supply of power from the AC power supply AC, respectively, and the timing at which the supply of power from the AC power supply AC is started (hereinafter referred to as “on time”). At t0, charging of the capacitors Cc and Ci connected to itself starts. Then, driving of the switching elements Q0 to Q2 is started at a timing when the both-end voltages of the capacitors Cc and Ci connected to itself reach a predetermined voltage. The DC voltage Vdc gradually increases from the above timing determined based on the voltage across the capacitor Cc by the operation of the voltage control unit 11 until reaching the steady voltage Vs, and after reaching the steady voltage Vs, When the input of power from the AC power supply AC is stopped, the steady voltage Vs is maintained until t4. In the example of FIG. 1, the timing at which the drive unit 21 of the inverter circuit 2 starts to drive the switching elements Q1 and Q2 (that is, the timing at which the output of AC power to the induction coil 5 is started. .) T1 is after the timing when the voltage control unit 11 of the DC power supply circuit 1 starts driving the switching element Q0.

  In the control circuit 3, the switch SW of the sweep circuit 31 is on / off controlled by a switch control unit (not shown), and is turned on at least at the start time t1 when the driving of the switching elements Q1, Q2 of the inverter circuit 2 is started. It is switched to the OFF state at a timing (hereinafter referred to as “preparation time end point”) t2 when a predetermined preparation time has elapsed from the start time t1. That is, arc discharge does not occur in the electrodeless discharge lamp 6 with the target value of the power supplied to the induction coil 5 during the period from the start time t1 to the end time t2 of the preparation time (hereinafter referred to as “start preparation period”). A start preparation operation that is kept low is performed, and feedback control is performed by the sweep circuit 31 and the feedback circuit 32 during the start preparation operation. As a result, the operation frequency becomes the extinguishing frequency f2. Thereafter, the operating frequency f gradually decreases to the lighting frequency f1 through the sweep operation by the sweep circuit 31 from the preparation time end point t2. Then, H discharge (arc discharge) is started in the electrodeless discharge lamp 6 at a certain time point (hereinafter referred to as “lighting time point”) after the operating frequency f becomes the lighting frequency f1, and the circuit is accordingly generated. 5 changes from the characteristic indicated by the curve A in FIG. 5 to the characteristic indicated by the curve B, whereby the amplitude of the coil voltage Vx becomes small. Thereafter, the switch SW of the sweep circuit 31 is maintained in the OFF state until the light is extinguished, and the operating frequency f is maintained at the lighting frequency f1.

  Here, when the light is extinguished, the input of the voltage Vd for charging the capacitor C1 is stopped in the sweep circuit 31, and the capacitor C1 is discharged through the resistor R2. As a result, the operating frequency f becomes a starting frequency f3 higher than the extinguishing frequency f2 at the starting time t1, and the preparation time after the operating frequency f gradually decreases to the extinguishing frequency f2 by charging the capacitor C1 during the starting preparation period. The extinction frequency f2 is maintained until the end time t2.

  According to the above configuration, the operating frequency f is started from the starting point frequency f3 higher than the extinguishing frequency f2 at the time of starting, so that compared with the case where the operating frequency f is started from the extinguishing frequency f2, the time immediately after the starting time t1 is increased. Since the rise of the amplitude of the coil voltage Vx becomes gentle, the electrical stress applied to the circuit components is reduced.

  Further, compared to the case where the operating frequency f is set to the lighting frequency f1 from the beginning without performing the start preparation operation, the change in the characteristics of the load circuit composed of the induction coil 5 and the electrodeless discharge lamp 6 is moderated at the start. Therefore, the amplitude of the coil voltage Vx and the DC voltage Vdc are stabilized.

  Furthermore, in the present embodiment, as already described, the extinction frequency f2 is set to such an extent that E discharge (glow discharge) is generated in the electrodeless discharge lamp 6, so that the operating frequency f is set to the lighting frequency f1 from the beginning. Or, compared with the case where the turn-off frequency f2 is made lower, the amplitude of the coil voltage Vx from when the operating frequency f is set to the turn-on frequency f1 to when H discharge (arc discharge) is actually started in the electrodeless discharge lamp 6 Since the period during which is relatively large is shortened, the electrical stress applied to the circuit components at the time of starting is reduced.

  Further, the feedback control of the sweep circuit 31 and the feedback circuit 32 suppresses the influence of variations in circuit component characteristics and the ambient temperature.

  By the way, when a general commercial power source is used as the AC power source AC, the input voltage Vin becomes zero or the input voltage Vin decreases for a very short time as in the period t4 to t0 ′ shown in FIG. Instantaneous low power may occur. When the electrodeless discharge lamp 6 is turned off by such an instantaneous low power, and then restarted at the timing t0 ′ when the supply of power from the AC power supply AC is normalized, the duration of the instantaneous low power is If the voltage across the capacitor C1 of the sweep circuit 31 is not lowered due to the short period, the operating frequency f immediately after the start is lower than that at the normal start, and therefore the amplitude of the coil voltage Vx is relatively large. Electrical stress on circuit components tends to increase. However, in the present embodiment, the operation frequency f when starting output of AC power from the inverter circuit 2 to the induction coil 5 is configured to be lower than that in the conventional example. Even after electricity, the electrical stress on the circuit components can be suppressed.

  Further, when the resistance R11 between the non-inverting input terminal of the operational amplifier OP1 and the capacitor C1 is not provided in the sweep circuit 31, the extinguishing frequency f2 is lowered to the same extent as described above, and the amplitude of the coil voltage Vx during the start preparation period is increased. In order to ensure, it is necessary to increase the resistance value of the resistor R10 connected in series with the switch SW. In this case, the discharge of the capacitor C1 after the light is turned off is delayed. On the other hand, in the present embodiment, by providing the resistor R11, both the low extinction frequency f2 and the discharge speed of the capacitor C1 are achieved.

(Embodiment 2)
Since the basic configuration of the present embodiment is the same as that of the first embodiment, common portions are denoted by the same reference numerals and description thereof is omitted.

  In the present embodiment, as shown in FIG. 6, the control circuit 3 detects a non-lighting of the electrodeless discharge lamp 6 based on the detection voltage Vxs output from the voltage detection circuit 4 and performs a predetermined protection operation. The point provided with 33 and the configuration of the sweep circuit 31 are different from those of the first embodiment.

  First, the sweep circuit 31 will be described. The resistor R11 between the non-inverting input terminal of the operational amplifier OP and the capacitor C1 is omitted, and the series circuit of the switch SW1 and the resistor R12, as compared with the first embodiment. Is added and connected in parallel to the capacitor C1. In addition, the sweep circuit 31 has a switch control unit (not shown) that controls on and off of the two switches SW and SW1. That is, the switch control unit turns on both the switches SW and SW1 of the sweep circuit 31 from the time when the electrodeless discharge lamp 6 is extinguished to the start time t1, thereby operating at the start time t1 as shown in FIG. The frequency f is set to a starting frequency f3 higher than the extinguishing frequency f2, and only one switch SW1 is turned off at the starting time point t1, so that the operating frequency f is gradually increased to the extinguishing frequency f2 by the time constant of the capacitor C1 and the resistors R2 and R10. Further, by turning off the other switch SW at the end time t2 of the preparation time, the operating frequency f is gradually lowered to the lighting frequency f1 by the time constant of the capacitor C1 and the resistor R2. Since such a switch control unit can be realized by a known technique, illustration and detailed description thereof are omitted.

  Next, the protection circuit 33 will be described. The protection circuit 33 includes a comparator CP1 having a non-inverting input terminal connected to the output terminal of the voltage detection circuit 4 and a reference voltage Vr2 input to the inverting input terminal. The protection circuit 33 detects the non-lighting based on the capacitor C3 charged by the output voltage of the comparator CP1 input through the resistor R9 and the voltage across the capacitor C3, and when the non-lighting is detected. A protection control unit 33a that stops the voltage control unit 11 of the DC power supply circuit 1 and the drive unit 21 of the inverter circuit 2 is provided.

  Specifically, the protection control unit 33a monitors the voltage across the capacitor C3, and detects that the electrodeless discharge lamp 6 is not lit at t5 when the voltage across the capacitor C3 exceeds a predetermined determination voltage. To start the protection operation. As shown in FIG. 7, the protection operation is an operation of stopping the voltage control unit 11 of the DC power supply circuit 1 and the drive unit 21 of the inverter circuit 2 for a predetermined time. After the protection operation is completed, the same operation as that at the normal start time is performed. The protection control unit 33a counts the number of protection operations, and when non-lighting is detected again after the protection operation is performed three times, the electrodeless discharge lamp 6 is disposed near the induction coil 5. It is determined that there is no load, and thereafter, the voltage control unit 11 of the DC power supply circuit 1 and the drive unit 21 of the inverter circuit 2 are kept stopped to protect the circuit. That is, after the first protection operation, intermittent oscillation is performed up to three times with two protection operations in between.

  According to the above configuration, the circuit can be protected by the protection operation or the subsequent stop. Further, the startability is improved as compared with the case where the DC power supply circuit 1 and the inverter circuit 2 are stopped without performing the intermittent oscillation as described above when non-lighting is detected.

  As the protective operation, instead of stopping the voltage control unit 11 of the DC power supply circuit 1 and the drive unit 21 of the inverter circuit 2 as described above, the amplitude of the coil voltage Vx is the amplitude at the end of the preparation period t2. The voltage control unit 11 of the DC power supply circuit 1 and the drive unit 21 of the inverter circuit 2 may be controlled so as to be smaller. By adopting this configuration, the increase width of the amplitude of the coil voltage Vx becomes small at the starting time t1 after the end of the protection operation, so that the electrical stress applied to the circuit components is further reduced.

  In each of the first and second embodiments, the DC power supply circuit 1 is another well-known DC power supply circuit such as a step-up / down converter in which a step-down converter (buck converter) and a step-up converter are combined. Also good. Further, a battery may be used as the power source of the DC power supply circuit 1 in place of the AC power supply AC. In this case, the diode bridge DB can be omitted. Further, a known integrated circuit may be used for the control circuit 3.

  The electrodeless discharge lamp lighting device of the first and second embodiments constitutes a lighting fixture 7 by being held by an appropriately shaped fixture body 71 together with the electrodeless discharge lamp 6 and the coupler 50 as shown in FIGS. can do. Since such a fixture main body 71 and the lighting fixture 7 can be realized by a well-known technique, detailed illustration and description thereof will be omitted.

  Also, in general, the electrodeless discharge lamp 6 has a longer life and is less likely to fail than a discharge lamp having an electrode inside, so that it is used in places where maintenance work is difficult such as in tunnels. It is suitable as a light source. Therefore, the above electrodeless discharge lamp lighting device may be used for the lighting device 7 for tunnel illumination having a structure as shown in FIGS. Hereinafter, the lighting fixture 7 of FIGS. 10A to 10C will be described in detail, with reference to FIG. 10A as the reference for the vertical and horizontal directions, and the vertical direction of FIG.

  10 (a) to 10 (c), the fixture body 71 is composed of a rectangular parallelepiped body 71a made of, for example, stainless steel, and a transparent material such as tempered glass. A cover 71b for closing and opening the 71a. Further, a U-shaped reflecting plate 71c made of, for example, aluminum and distributing light of the electrodeless discharge lamp 6 forward is fixed to the inner bottom surface of the body 71a, and the electrodeless electrode housed in the instrument body 71 is fixed. The light from the discharge lamp 6 is emitted forward through the cover 71b. Further, the inner surface of the body 71a is electrically connected to the coupler 50 to which the electrodeless discharge lamp 6 is attached, the case 10 housing the electrodeless discharge lamp lighting device, and the DC power supply circuit 1 in the case 10. Terminal blocks 8 are fixed to each other. The terminal block 8 is connected to the other end of an electric wire (not shown) having one end connected to the AC power supply AC. The DC power supply circuit 1 is connected to the AC power supply via the electric wire and the terminal block 8. Electrically connected to AC. In addition, an electric wire insertion hole 71d for inserting an electric wire connected to the terminal block 8 is vertically provided in the lower wall of the body 71a. Further, the cover 71b is connected to the upper end portion of the body 71a via the hinge 71e at the upper end portion, so that the cover 71b is closed at the closed position and the closed position as shown in FIGS. It can rotate with respect to the body 71a in the plane seen from the left-right direction between the open position where the lower end of the body is directed forward and the body 71a is released. A latch 71f that locks the lower end of the cover 71b in the closed position is provided at the lower end of the body 71a. Since the hinge 71e and the latch 71f as described above can be realized by a well-known technique, detailed illustration and description are omitted. Furthermore, on the rear surface of the body 71a, two mounting legs 71g made of, for example, a steel plate and fixed to the mounting surface (not shown) such as a wall surface are fixed side by side. Yes. The upper and lower end portions of each mounting foot 71g protrude vertically from the body 71a as viewed from the front, and screw insertion holes 71h are provided through the protruding portions in the front-rear direction. The instrument body 71 is screwed and fixed to the mounting surface by a screw (not shown) that is inserted into the screw insertion hole 71h and screwed into the mounting surface.

  Further, in the various lighting fixtures 7 described above, a battery (not shown) may be housed in the fixture main body 71, and the DC power supply circuit 1 may use the battery as a power source during a power failure. Since such a lighting fixture 7 can be realized by a known technique, detailed illustration and description thereof are omitted.

It is explanatory drawing which shows operation | movement of Embodiment 1 of this invention. It is a circuit block diagram which shows the same as the above. It is a perspective view which shows an example of the usage pattern same as the above. It is explanatory drawing which shows an example of the structure of an electrodeless discharge lamp. It is explanatory drawing which shows the relationship between an operating frequency and a coil voltage. It is a circuit block diagram which shows Embodiment 2 of this invention. It is explanatory drawing which shows operation | movement same as the above. It is the partially broken front view which shows an example of the lighting fixture using the same. It is a front view which shows another example of the lighting fixture using the same as the above. (A)-(c) shows another example of the lighting fixture using each same as the above, (a) is a front view, (b) is a bottom view, (c) is a left view.

Explanation of symbols

1 DC power circuit 2 Inverter circuit (Power circuit in claims)
DESCRIPTION OF SYMBOLS 3 Control circuit 4 Voltage detection circuit 5 Induction coil 6 Electrodeless discharge lamp 7 Lighting fixture 71 Appliance main body

Claims (4)

An induction coil disposed close to the electrodeless discharge lamp;
A power supply circuit for supplying AC power to the induction coil;
A control circuit for controlling the power supply circuit,
When starting the electrodeless discharge lamp, immediately after the output of AC power from the power supply circuit to the induction coil is started, the control circuit gradually increases the power output from the power supply circuit to the induction coil. An electrodeless discharge lamp lighting device.   The control circuit, when starting the electrodeless discharge lamp, before the electric power supplied to the induction coil becomes so high that arc discharge occurs in the electrodeless discharge lamp, the power supplied to the induction coil over a predetermined time, 2. The electrodeless discharge lamp lighting device according to claim 1, wherein a starting preparation operation for controlling the power supply circuit is performed so as to maintain the electrodeless discharge lamp so low that arc discharge does not occur. A voltage detection circuit that outputs a detection voltage that is a DC voltage having a higher voltage value as the amplitude of the voltage output from the power supply circuit to the induction coil increases,
3. The electrodeless discharge lamp lighting device according to claim 2, wherein the control circuit performs feedback control for maintaining the output power of the power supply circuit constant based on the detection voltage output from the voltage detection circuit during the start preparation operation. .   The instrument main body which hold | maintains the electrodeless discharge lamp lighting device of any one of Claims 1-3, and the electrodeless discharge lamp and electrodeless discharge lamp lighting device which are lighted by an electrodeless discharge lamp lighting device A lighting fixture comprising:

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