JP2003229292A - Magnetron driving power source device for electrodeless light source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetron driving power source for an electrodeless light source capable of maintaining stable light emission, dispensing with a waiting time up to re-lighting without turning off the electrodeless light source lamp even when an instantaneous stop of the commercial power supply or an abnormal voltage drop are generated. <P>SOLUTION: The magnetron driving power source for an electrodeless light source comprises a power source voltage detecting circuit 14 detecting the generation of an instantaneous stop of the commercial power supply 1 or an abnormal voltage drop, and a power reduction signal circuit 16 installed at the inside of a power control signal circuit 15, reducing and controlling the output power of a high voltage circuit 6 to the extent of the minimum power by which, the electrodeless light source lamp 11 can maintain a lighting state, when an abnormality in the commercial power supply 1 is detected by the power source voltage detecting circuit 14. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron drive power supply device for an electrodeless light source that lights an electrodeless light source lamp by using microwave energy and utilizes the light.

[0002]

2. Description of the Related Art A conventional magnetron drive power supply device for an electrodeless light source will be described below with reference to the drawings. Figure 3
Shows a main circuit configuration diagram of a conventional magnetron drive power supply device for an electrodeless light source. In the figure, a magnetron drive power supply device 2 for an electrodeless light source connected to a commercial AC power supply 1 is shown.
Then, the AC voltage supplied from the commercial AC power supply 1 is rectified by the rectifier circuit 3 and then operates at a high power factor through the power factor control circuit 4, but as it is, it has a high ripple output and is smoothed by the electrolytic capacitor 5. Converted to DC voltage. The DC voltage thus converted is boosted by the high voltage circuit 6 and applied to the magnetron 7. Here, the high-voltage circuit 6 has a switching element 9 that is on / off controlled by a power control signal circuit 8, and the direct current supplied to the magnetron 7 is controlled by the switching operation of the switching element 9, and the microwave output of the magnetron 7 is Controlled. In this way the magnetron 7
The microwave 71 generated from the electromagnetic wave passes through the waveguide 10 and reaches the electrodeless light source lamp 11. Inside the electrodeless light source lamp 11, there is provided a bulb 12 filled with a solid substance made of a mixture of sulfur, indium, etc. and a gas such as argon gas.
2 and irradiate the bulb 12 with microwave energy
The substance inside becomes plasma and emits as visible light or UV light.

[0003]

However, in the electrodeless light source device having the conventional structure as described above, when the commercial AC power supply is momentarily interrupted or an abnormal voltage drop occurs, the magnetron does not normally oscillate and the electrodeless light source lamp is used. Turns off. Then, the inside of the bulb 12 in the high temperature state is in a high pressure state due to the vaporized substance, and in this state, the vaporized substance is returned to the original state because it does not emit light even if microwave is irradiated again. It took time to cool the valve to reduce the pressure. Therefore, in the conventional magnetron drive power supply device for an electrodeless light source, when the electrodeless light source lamp 11 is once turned off due to a momentary power failure of the commercial AC power supply or an abnormal voltage drop, it is connected to the power control signal circuit 8 for relighting. By the timer 13 of
The operation of the magnetron was stopped for the time required to cool the valve 12.

The present invention can maintain a stable light emission state without waiting for re-lighting without turning off the electrodeless light source lamp even when a momentary power failure of the commercial AC power source or an abnormal voltage drop occurs. An object of the present invention is to provide a magnetron drive power supply device for an electrodeless light source.

[0005]

In order to solve the above-mentioned problems, a magnetron drive power supply device for an electrodeless light source according to the present invention has a rectification circuit for rectifying an AC voltage of a commercial AC power supply and an output from the rectification circuit. A power factor control circuit for controlling voltage and current to obtain a high power factor, an electrolytic capacitor for smoothing the output voltage of the power factor control circuit and converting it to a DC voltage, and a DC voltage converted by the electrolytic capacitor to a magnetron drive voltage. A high-voltage circuit for boosting up to, a magnetron for generating microwaves by the power supplied from the high-voltage circuit, a power control signal circuit for controlling output power of the high-voltage circuit, and a waveguide for transmitting microwave energy, An electrodeless light source lamp that emits visible light or UV light by converting the substance inside the bulb into plasma by microwave energy In the electrodeless light source device, a power supply voltage detection circuit for detecting that the AC voltage of the commercial AC power supply has momentarily stopped or dropped, and the power control signal circuit for supplying the power supply voltage detection circuit to the commercial AC power supply And a power down signal circuit for controlling to reduce the output power of the high voltage circuit to the minimum power that can maintain the lighting state of the electrodeless light source lamp when a power failure or abnormal voltage drop is detected.

With this configuration, when the commercial AC power source experiences an instantaneous power failure or abnormal voltage drop, the power source voltage detection circuit detects that the voltage is lower than a predetermined voltage. When this signal enters the power down signal circuit, the output power of the high voltage circuit is controlled to be reduced, and the microwave output generated from the magnetron is reduced. The current supplied from the high voltage circuit to the magnetron at this time is the minimum current at which the substance in the bulb of the electrodeless light source lamp can maintain the plasma state. That is, the electrodeless light source lamp emits a minimum amount of light and can maintain the lighting state. By controlling the reduction of the current supplied from the high-voltage circuit to the magnetron in this manner, the electric charge charged in the electrolytic capacitor does not suddenly decrease, and it is possible to prevent the electrodeless light source lamp from being turned off.

Further, if the electrodeless light source lamp emits a minimum amount of light and the substance inside the bulb maintains the plasma state, when the abnormal voltage detection signal from the power supply voltage detection circuit is stopped, the power down signal circuit is used. Stop the reduction control of the output power of the high voltage circuit, switch to the control by the power control signal circuit and restore the output of the high voltage circuit to normal power,
The electrodeless light source lamp can also be immediately returned to the normal light emitting state. Since the electrodeless light source lamp is not turned off in this way, a waiting time for cooling the bulb before relighting is unnecessary, and the light emitting state can be maintained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a main circuit configuration diagram showing an embodiment of a magnetron drive power supply device for an electrodeless light source according to the present invention, and FIG. 2 shows a power supply voltage detection circuit and a power control signal circuit shown in FIG. It is a circuit block diagram which shows one Embodiment. In the figure, the same components as those of the conventional one are designated by the same reference numerals and the description thereof is omitted.

As shown in FIG. 1, the magnetron drive power supply device for an electrodeless light source according to the present invention includes a power supply voltage detection circuit 14 for detecting the occurrence of an instantaneous power failure or abnormal voltage drop of the commercial AC power supply 1, and a power supply. When the power supply voltage detection circuit 14 detects an abnormality in the commercial AC power supply 1 inside the control signal circuit 15, the power for controlling the output power of the high voltage circuit 6 to the minimum power at which the electrodeless light source lamp 11 can maintain the lighting state. A down signal circuit 16 is provided. That is, when the power supply voltage detection circuit 14 detects that the voltage is lower than the predetermined voltage, a signal that the voltage drop has been detected enters the power down signal circuit 16 and controls the switching element 9 of the high voltage circuit 6 so that the magnetron 7 outputs the signal. Reduce the microwave power generated. At this time, the high voltage circuit 6 to the magnetron 7
Is supplied to the bulb 1 of the electrodeless light source lamp 11.
It is the minimum electric power with which the substance inside 2 can maintain the plasma state.
That is, the electrodeless light source lamp 11 enters the minimum light emitting state and maintains the lighting state.

As described above, even when the commercial AC power supply 1 is momentarily cut off or an abnormal voltage drop occurs, the electric current supplied from the high voltage circuit 6 to the magnetron 7 is controlled to be reduced, so that the electrolytic capacitor 5 is charged. It is possible to prevent the electrodeless light source lamp 11 from being extinguished because the electric charge does not decrease sharply.

Further, if the electrodeless light source lamp 11 is in the minimum light emitting state and the substance in the bulb 12 is maintained in the plasma state, the power is not supplied when the abnormal voltage detection signal from the power supply voltage detection circuit 14 is stopped. The power control signal circuit 1 is stopped by stopping the output power reduction control by the down signal circuit 16.
The output of the high-voltage circuit 6 can be returned to normal power by switching to the normal control by 5, and the electrodeless light source lamp 11 can be immediately returned to the normal light emitting state.

Further, as shown in FIG. 2, in the power control signal circuit, the output setting volume voltage 18 for the reference voltage source 17 divided into a predetermined voltage value from a DC power source (not shown) on the circuit is set. The difference is amplified by the error amplifier 19, and the amplified signal is converted into P by the PWM converter 20.
Convert to a WM (pulse width modulation) signal. The PWM signal turns on / off the switching element 9 of the high-voltage circuit 6 to control the output power. The power supply voltage detection circuit 14 also includes a diode bridge 21 that rectifies the voltage of the commercial AC power supply 1, a smoothing capacitor 22 that smoothes the rectified voltage, a voltage dividing resistor 23 that smoothes the abnormal voltage threshold, and a smoothing capacitor. The voltage comparator 24 compares the generated voltage with the threshold value of the abnormal voltage. Further, the power down signal circuit 16 is a switch 25 which is turned on / off by the output of the power supply voltage detection circuit 14 and a current supplied from the high voltage circuit 6 to the magnetron 7 causes the substance in the bulb 12 of the electrodeless light source lamp 11 to maintain a plasma state. It is configured with a power down voltage 26 so that the minimum power is possible.

Therefore, when the voltage of the commercial AC power supply 1 decreases and the smoothed voltage in the power supply voltage detection circuit 14 becomes smaller than the preset abnormal voltage threshold value, the voltage comparator 24 applies a voltage to the switch 25. An abnormal detection signal is output. This detection signal causes the switch 25
Is turned on, the voltage of the power-down voltage 26 becomes the input of the error amplifier 19, and the bulb 12 of the electrodeless light source lamp 11 is turned on.
The minimum power that allows the internal substance to maintain the plasma state is supplied to the magnetron 7. Next, when the abnormal voltage detection signal from the power supply voltage detection circuit 14 stops, the switch 25
Is turned off, and the output setting volume voltage 18 changes to the error amplifier 1
It becomes the input of 9 and returns to the normal power control.

As described above, by completely extinguishing the electrodeless light source lamp in the event of a momentary power failure or abnormal voltage drop, there is no need for a waiting time for cooling the bulb before re-lighting, and a light emitting state is maintained. Is possible.

[0016]

As described above, according to the present invention,
By providing the power supply voltage detection circuit and the power-down signal circuit, the electrodeless light source lamp can maintain the minimum light-emission state and prevent complete extinction even in the event of a momentary power failure or abnormal voltage drop of the commercial AC power supply. . Further, when the commercial AC power supply returns to a normal voltage, the electrodeless light source lamp can immediately return from the minimum light emitting state to the normal light emitting state.

[Brief description of drawings]

FIG. 1 is a main circuit configuration diagram of a magnetron drive power supply device for an electrodeless light source according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram showing an embodiment of a power supply voltage detection circuit and a power control signal circuit shown in FIG.

FIG. 3 is a main circuit configuration diagram of a conventional magnetron drive power supply device for an electrodeless light source.

[Explanation of symbols]

14 Power supply voltage detection circuit 15 Power control signal circuit 16 Power-down signal circuit 17 Reference voltage source 18 Output setting volume voltage 19 Error amplifier 20 PWM converter 21 diode bridge 22 Smoothing capacitor 23 division resistance 24 voltage comparator 25 switch 26 Power-down voltage

Claims (3)

[Claims] 1. A rectifier circuit for rectifying an AC voltage of a commercial AC power supply, a power factor control circuit for controlling a voltage and a current output from the rectifier circuit to obtain a high power factor, and an output voltage of the power factor control circuit. , A high-voltage circuit for boosting the direct-current voltage converted by the electrolytic capacitor to a magnetron drive voltage, a magnetron for generating microwaves by the power supplied from the high-voltage circuit, It is composed of a power control signal circuit for controlling the output power of the high voltage circuit, a waveguide for transmitting microwave energy, and an electrodeless light source lamp that emits visible light or UV light by causing the substance inside the bulb to be plasma by the microwave energy. The electrodeless light source device detects that the AC voltage of the commercial AC power supply has momentarily stopped or dropped. A power supply voltage detection circuit and a power control signal circuit, in which the electrodeless light source lamp lights the output power of the high voltage circuit when the power supply voltage detection circuit detects an instantaneous power failure or abnormal voltage drop of the commercial AC power supply. And a power-down signal circuit for controlling the reduction to the minimum power that can maintain the above. 2. The power supply voltage detection circuit includes a diode bridge that rectifies the voltage of the commercial AC power supply, a smoothing capacitor that smoothes the voltage rectified by the diode bridge, and a voltage dividing resistor that sets a threshold value of the abnormal voltage. 2. The magnetron drive power supply device for an electrodeless light source according to claim 1, further comprising a voltage comparator that compares the smoothed voltage with a threshold value of the abnormal voltage. 3. The power down signal circuit is a switch that is turned on and off by the output of the power supply voltage detection circuit, and the current supplied from the high voltage circuit to the magnetron is the minimum current that allows the substance in the bulb of the electrodeless light source lamp to maintain a plasma state. The magnetron drive power supply device for an electrodeless light source according to claim 1, wherein the power down setting voltage source is as follows.