JPH1145792A - Electrodeless discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure an electrodeless discharge lamp to be lighted, prevent excessive current through a high-frequency power supply circuit from damaging elements, and ensure the electrodeless discharge lamp to start, by providing priority for one of actions of the high-frequency power supply circuit and a starter circuit than an action of a direct current power supply circuit when the electrodeless discharge lamp is started. SOLUTION: A direct current power supply circuit 4 which supplies direct current to a high-frequency power supply circuit 3 is provided, and a commercial power supply circuit AC is connected with the input terminal of the direct current power supply circuit 4. A starter circuit 5 has a starter electrode 7 near an electrodeless discharge lamp 1, and supports starting of the electrodeless discharge lamp 1 due to supply of high voltage. High-frequency current flows from the high-frequency power supply circuit 3 to an induction coil 2 to generate high-frequency magnetic field. During starting, the direct current power supply circuit 4, the starter circuit 5, the high-frequency power supply circuit 3, and a matching exchange circuit 6 are operated in this order. The electrodeless discharge lamp 1 can be certainly lighted without losing impedance matching for the high-frequency power supply circuit 3 and the induction coil 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeless discharge lamp lighting device for inducing a high-frequency electromagnetic field in an induction coil disposed near an electrodeless discharge lamp to light the electrodeless discharge lamp. In particular, when starting an electrodeless discharge lamp.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a conventional electrodeless discharge lamp lighting device. The electrodeless discharge lamp 1 is configured such that a rare gas or a substance or metal vapor which is excited and emitted by discharge of a rare gas is sealed in a bulb hermetically formed of a translucent material such as quartz or ceramics. Is coated with a phosphor as needed. On the outer periphery of the electrodeless discharge lamp 1, a high-frequency electromagnetic field applying means (induction coil 2) formed of a metal having good conductivity is arranged in close proximity. The high frequency power supply circuit 3 is connected to this induction coil 2 via a matching circuit 9
Is connected. The high-frequency power supply circuit 3 is connected to the DC power supply E and generates high-frequency power. By passing a high-frequency current of several MHz to several hundred MHz from the high-frequency power supply circuit 3 to the induction coil 2, a high-frequency electromagnetic field is generated in the induction coil 2, high-frequency power is supplied to the electrodeless discharge lamp 1, and electrodeless discharge is performed. A high frequency plasma current is generated in the electric lamp 1 to generate ultraviolet light or visible light. Here, the matching circuit 9 sets the load impedance as viewed from the high-frequency power supply circuit 3 to an appropriate value when the lighting of the electrodeless discharge lamp 1 is stable so that high-frequency power can be efficiently transmitted when the lighting of the electrodeless discharge lamp 1 is stable. It is designed to be. The igniter circuit 5 has a starting electrode 7 in the vicinity of the electrodeless discharge lamp 1 and is a circuit for supplying a high voltage to this electrode to assist in starting the electrodeless discharge lamp 1.

FIG. 7 shows a specific example of a conventional electrodeless discharge lamp lighting device.
It is a circuit diagram. In the figure, reference numeral 31 denotes an oscillation using the crystal unit X.
Circuit, coil L₆And capacitor C_FifteenLow Q
A tuning circuit is configured to be an unadjusted oscillator. Oscillation times
The preamplifier 32 that amplifies the oscillation output of the path 31
Jista Q_FourClass C amplification by the coil L_FiveWhen
Capacitor C₁₇Tuned to the oscillation frequency by
doing. Resistance R₈~ R_TenConsists of an attenuator
And the resistance R₁₁Is the coil L_FiveTo lower the Q of
Has been entered. The filter circuit 33 includes a choke coil L
_Three, Capacitor C_FourHigh frequency DC power supply
Prevents returning to E. Output of preamplifier 32
The main amplifier 34, which amplifies the power further with high frequency power, is
-MOSFET (hereinafter referred to as transistor) Q_FiveBy
Amplifier. Coil L ₇Is the transistor Q
_FiveInserted to counteract the input capacitance of
And the resistance R₁₂Is the transistor Q_FiveInput impedance of
Connected to match the output of the preamplifier 32.
You. The matching circuit 9 is a capacitor C₁₈~ C₂₀Etc.
And the output of the main amplifier 34 and the subsequent electrodeless discharge lamp 1
And impedance matching with induction coil 2
You.

[0004] As described above, the electrodeless discharge lamp lighting device includes:
A matching circuit 9 is provided for efficiently supplying the high-frequency output of the high-frequency power supply circuit 3 to the induction coil 2 serving as a load and the electrodeless discharge lamp 1 (hereinafter referred to as a load Lp). However, the input impedance of the load Lp viewed from the matching circuit 9 greatly changes depending on the state of the electrodeless discharge lamp 1. That is, when the electrodeless discharge lamp 1 is turned off (during start-up), the load Lp is substantially only the induction coil 2,
While the induction component increases, the induction coil 2 is coupled to plasma (plasma resistance) generated inside the electrodeless discharge lamp 1 when the electrodeless discharge lamp 1 is lit (during lighting). , The resistance component becomes larger than at the start.
Then, for example, when the matching circuit 9 is designed to perform impedance matching between the load Lp and the high-frequency power supply circuit 3 in a state where the electrodeless discharge lamp 1 is turned on, at the time of starting, the load Lp and the high-frequency power supply circuit 3 The impedance matching of the main amplifier 34 is not matched, and a reflected power is applied to the high-frequency power supply circuit 3. Therefore, a stress is applied to the high-frequency power supply circuit 3, and particularly, an excessive stress is applied to the transistor Q ₅ of the main amplifier 34.

To solve this problem, as shown in FIG. 8, a matching circuit whose impedance is matched at the time of starting and a matching circuit whose impedance is matched at the time of lighting are provided.
Means for switching between them has been devised (Japanese Utility Model Application Laid-Open No. 5-20297). Hereinafter, this is called a matching switching circuit 6. In FIG. 8, Sw indicates a switch, and by switching the switch Sw, impedance matching between startup and lighting can be achieved.

[0006]

However, even in the prior art described above, for example, when the DC power supply E is constituted by a complete smoothing circuit of a capacitor input, the output voltage thereof becomes a predetermined value when the power is turned on. When the high-frequency power is supplied from the high-frequency power supply circuit 3 to the induction coil 2 and the starting voltage from the starting circuit 5 is applied to the electrodeless discharge lamp 1 during the rising time, Even if the impedance matching at the time of starting is performed by the matching switching circuit 6, since the power supply voltage input to the high-frequency power supply circuit 3 has changed, the output power from the high-frequency power supply circuit 3 also changes. , Matching switching circuit 6
However, since the electrodeless lamp 1 is forcibly started even though the impedance matching is not accurately performed, there is a problem that a large loss is given to components used in the high-frequency power supply circuit 3.

[0007] As described in Japanese Patent Application No. 8-31512, a configuration including a variable matching circuit for continuously changing the matching in accordance with the impedance of a load has an electrodeless discharge lamp 1 and an induction coil 2. When the load is used, the impedance changes rapidly and steeply at the time of starting, so that a continuous change in matching cannot be followed, and in this case, there still remains a problem that impedance matching cannot be accurately performed.

Further, as another means for matching the impedance between the induction coil 2 and the high-frequency power supply circuit 3 at the time of starting the electrodeless discharge lamp 1, there is a method of changing the frequency of the high-frequency power supply circuit 3 only at the time of start-up. However, in this method, the frequency must be changed in a short time at the time of starting the electrodeless discharge lamp 1 to ensure the impedance matching between the induction coil 2 and the high-frequency power supply circuit 3, but the frequency of the high-frequency power supply circuit 3 is high. Therefore, there is a drawback that it is easily affected by noise, very difficult to control, and the circuit configuration becomes complicated.

Accordingly, an object of the present invention is to provide an electrodeless discharge lamp lighting device having a DC power supply circuit, a high-frequency power supply circuit, a matching circuit and a starting circuit, in which the electrodeless discharge lamp does not light or an excessive current is generated. An object of the present invention is to provide an electrodeless discharge lamp lighting device that can start an electrodeless discharge lamp reliably without flowing into a high-frequency power supply circuit and destroying elements, and can be further reduced in size.

[0010]

According to the present invention, in order to solve the above-mentioned problems, as shown in FIG. 1, an electrodeless discharge lamp 1 and an electrodeless discharge lamp 1 are disposed in close proximity to the electrodeless discharge lamp 1. Induction coil 2, a high-frequency power supply circuit 3 for supplying high-frequency power to the induction coil 2, a DC power supply circuit 4 for supplying DC power to the high-frequency power supply circuit 3, and assists in starting the electrodeless discharge lamp 1. And a matching switching circuit 6 disposed between the induction coil 2 and the high-frequency power supply circuit 3 to enable impedance matching between the induction coil 2 and the high-frequency power supply circuit 3 when the electrodeless discharge lamp 1 is started and lit. In the electrodeless discharge lamp lighting device, when the electrodeless discharge lamp 1 is started, one of the operation of the high-frequency power supply circuit 3 and the starting circuit 5 has a higher priority than the operation of the DC power supply circuit 4. It is.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 shows a first embodiment of the present invention. The basic circuit configuration of the present embodiment is the same as that of the conventional example of FIG. 5, and a discharge gas such as an inert gas or a metal vapor is provided in a light-transmitting glass bulb or a glass bulb having a phosphor applied to the inner surface. , A high-frequency power supply circuit 3 connected to the induction coil 2 and supplying high-frequency power to the induction coil 2, A matching switching circuit 6 that matches the impedance of the induction coil 2 and the high-frequency power supply circuit 3 at the time of lighting and at the time of lighting and efficiently transmits high-frequency power to the electrodeless discharge lamp 1 is provided. In the present embodiment, a DC power supply circuit 4 (for example, a step-up chopper circuit) for supplying DC power to the high-frequency power supply circuit 3 is provided, and a commercial power supply AC is connected to an input terminal of the DC power supply circuit 4. The starting circuit 5 has a starting electrode 7 near the electrodeless discharge lamp 1, and supplies a high voltage to this electrode to assist the starting of the electrodeless discharge lamp 1. Then, a high-frequency current of several hundred KHz to several hundred MHz is supplied from the high-frequency power supply circuit 3 to the induction coil 2 to generate a high-frequency electromagnetic field in the induction coil 2 and supply high-frequency power to the electrodeless discharge lamp 1. A high-frequency plasma current is generated to generate ultraviolet light or visible light.

The DC power supply circuit 4 at the time of starting according to the present embodiment.
Output voltage, high-frequency power supply circuit 3 output voltage, starting circuit 5
FIG. 2 is a diagram for explaining the operation of the output voltage and the state of the matching switching circuit 6 (whether it is on the starting side or on the lighting side).
Hereinafter, FIG. 2 will be described. At the time of startup, when the commercial power supply AC is turned on at t ₁ , first, the DC power supply circuit 4
(Step-up chopper circuit) and the starting circuit 5 operate, and the starting circuit 5 applies a high voltage to the starting electrode 7. At this time,
The state of the matching switching circuit 6 is on the starting side (the induction coil 2 and the high-frequency power supply circuit 3 are in an impedance matching state during the starting state). When the output voltage of the DC power supply circuit 4 is substantially desired voltage, high-frequency power supply circuit 3 is operated at t _2. As a result, the electrodeless discharge lamp 1 is turned on at t ₃ , and the matching switching circuit 6 is switched from the starting side to the lighting side (in the lighting state, the induction coil 2 and the high-frequency
Is brought into an impedance matching state).

In this embodiment, when the electrodeless discharge lamp 1 is started, the DC power supply circuit 4, the starting circuit 5, the high-frequency power supply circuit 3, and the matching switching circuit 6 are operated in this order. Since the high-frequency power supply circuit 3 and the matching switching circuit 6 operate after the voltage becomes constant, the impedance matching between the high-frequency power supply circuit 3 and the induction coil 3 does not shift, and the electrodeless discharge lamp 1 is reliably turned on. Can be.

In this embodiment, the operation of the next circuit is started when the output voltage of the DC power supply circuit 4 is stabilized at a certain desired value. You may move on to the operation.

(Embodiment 2) The basic circuit configuration of a second embodiment of the present invention is the same as that of the first embodiment, and only the operation is different. Therefore, a duplicate description will be omitted, and the circuit operation will be described. The difference between the first embodiment and the present embodiment is the operation order of the high-frequency power supply circuit 3 and the starting circuit 5. FIG. 3 is a diagram illustrating the operation of the DC power supply circuit 4, the high-frequency power supply circuit 3, the starting circuit 5, and the matching switching circuit 6 at the time of starting.

FIG. 3 will be described below. At the time of starting, when the commercial power supply AC is turned on at t ₁ , the starting circuit 5 operates first, and the starting circuit 5 applies a high voltage to the starting electrode 7. At this time, the state of the matching switching circuit 6 is
It is on the starting side (the induction coil 2 and the high-frequency power supply circuit 3 are in an impedance matching state during the starting state). Thereafter, the DC power supply circuit 4 (step-up chopper circuit) at t ₂ is operated. When the output voltage of the DC power supply circuit 4 is substantially desired voltage, high-frequency power supply circuit 3 is operated at t _3. Thereby, the electrodeless discharge lamp 1 at t ₄ is lit, the process proceeds to the matching switching circuit 6 is turned side from the starting side (induction coil 2 and the high-frequency power supply circuit 3 is in the impedance matching state when the lighting state) .

(Embodiment 3) The basic circuit configuration of the third embodiment of the present invention is the same as that of the first embodiment, and only the operation is different. Therefore, a duplicate description will be omitted and the circuit operation will be described. The difference between the first embodiment and the present embodiment is the operation order of the high-frequency power supply circuit 3 and the starting circuit 5. FIG. 4 is a diagram illustrating the operation of the DC power supply circuit 4, the high-frequency power supply circuit 3, the starting circuit 5, and the matching switching circuit 6 at the time of starting.

FIG. 4 will be described below. At the start, when the commercial power source AC is turned by t _1, first with the DC power supply circuit 4 (step-up chopper circuit) is operated, the high-frequency power supply circuit 3 is operated. At this time, the state of the matching switching circuit 6 is on the starting side (the induction coil 2 is in the starting state).
And the high frequency power supply circuit 3 is in an impedance matching state)
It is in. When the output voltage of the DC power supply circuit 4 reaches a substantially desired voltage, the starting circuit 5 operates at t ₂ to apply a high voltage to the starting electrode 7. Thereby, the electrodeless discharge lamp 1 is lit at t _3, the process proceeds to the matching switching circuit 6 is turned side from the starting side (induction coil 2 and the high-frequency power supply circuit 3 is impedance matching state when the lighting state) .

(Embodiment 4) The basic circuit configuration of the fourth embodiment of the present invention is the same as that of the first embodiment, and only the operation is different. Therefore, a duplicate description will be omitted and the circuit operation will be described. The difference between the first embodiment and the present embodiment is the operation order of the high-frequency power supply circuit 3 and the starting circuit 5. FIG. 5 is a diagram for explaining the operation of the DC power supply circuit 4, the high-frequency power supply circuit 3, the starting circuit 5, and the matching switching circuit 6 at the time of starting.

FIG. 5 will be described below. At the start, when the commercial power source AC is turned by t _1, first high-frequency power supply circuit 3 is operated. At this time, the state of the matching switching circuit 6 is on the starting side (the induction coil 2 and the high-frequency power supply circuit 3 are in an impedance matching state during the starting state). Thereafter, the DC power supply circuit 4 (step-up chopper circuit) at t ₂ is operated. When the output voltage of the DC power supply circuit 4 reaches a substantially desired voltage, the starting circuit 5 operates at t ₃ to apply a high voltage to the starting electrode 7. Thereby, the electrodeless discharge lamp 1 at t ₄ is turned, the matching switching circuit 6
Shifts from the starting side to the lighting side (in the lighting state, the induction coil 2 and the high-frequency power supply circuit 3 are in an impedance matching state).

[0021]

According to the present invention, an electrodeless discharge lamp, an induction coil disposed close to the electrodeless discharge lamp, a high frequency power supply circuit for supplying high frequency power to the induction coil,
A DC power supply circuit for supplying DC power to the high-frequency power supply circuit, a starting circuit for assisting the starting of the electrodeless discharge lamp, and an electrodeless electrode disposed between the induction coil and the high-frequency power supply circuit. In the electrodeless discharge lamp lighting device having a matching switching circuit that is enabled at the time of starting and lighting of the discharge lamp, when the electrodeless discharge lamp is started, one of the high-frequency power supply circuit and the starting circuit operates by direct current. Since the priority is given to the operation of the power supply circuit, when starting the electrodeless discharge lamp, the impedance matching between the high-frequency power supply circuit and the induction coil can be reliably performed by the matching switching circuit, and the electrodeless discharge lamp does not light up, Alternatively, it is possible to reliably start the electrodeless discharge lamp without causing an excessive current to flow to the high-frequency power supply circuit and destroying the element. Can provide-type capable electrodeless discharge lamp lighting device.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the first embodiment of the present invention.

FIG. 3 is an operation explanatory diagram of a second embodiment of the present invention.

FIG. 4 is an operation explanatory diagram of a third embodiment of the present invention.

FIG. 5 is an operation explanatory view of Embodiment 4 of the present invention.

FIG. 6 is a block circuit diagram showing the entire configuration of Conventional Example 1.

FIG. 7 is a circuit diagram showing a specific circuit configuration of Conventional Example 1.

FIG. 8 is a circuit diagram showing a specific circuit configuration of Conventional Example 2.

[Explanation of symbols]

 Reference Signs List 1 electrodeless discharge lamp 2 induction coil 3 high frequency power supply circuit 4 DC power supply circuit 5 starting circuit 6 matching switching circuit

Claims (9)

[Claims] 1. An electrodeless discharge lamp, an induction coil disposed close to the electrodeless discharge lamp, a high-frequency power supply circuit for supplying high-frequency power to the induction coil, and a direct-current power supply to the high-frequency power supply circuit A DC power supply circuit, a starting circuit that assists in starting the electrodeless discharge lamp, and an impedance matching circuit disposed between the induction coil and the high-frequency power supply circuit for impedance matching between the two when starting and lighting the electrodeless discharge lamp. In the electrodeless discharge lamp lighting device provided with a matching switching circuit that enables the operation, when the electrodeless discharge lamp is started, one of the operation of the high-frequency power supply circuit and the starting circuit has priority over the operation of the DC power supply circuit. An electrodeless discharge lamp lighting device, characterized in that: 2. When starting the electrodeless discharge lamp,
2. The electrodeless discharge lamp lighting device according to claim 1, wherein the operation of the high-frequency power supply circuit has a higher priority than the operation of the starting circuit. 3. When starting the electrodeless discharge lamp,
2. An electrodeless discharge lamp lighting device according to claim 1, wherein the operation of said starting circuit is given priority over the operation of said high frequency power supply circuit. 4. When starting the electrodeless discharge lamp,
2. The electrodeless discharge lamp lighting device according to claim 1, wherein the DC power supply circuit and the starting circuit operate substantially simultaneously. 5. When starting the electrodeless discharge lamp,
The electrodeless discharge lamp lighting device according to claim 1, wherein the DC power supply circuit and the high-frequency power supply circuit operate substantially simultaneously. 6. The operating frequency of the high-frequency power supply circuit is several hundred kHz to several hundred MHz.
6. The electrodeless discharge lamp lighting device according to any one of claims 1 to 5. 7. The electrodeless discharge lamp lighting device according to claim 1, wherein the DC power supply circuit is a step-up chopper circuit. 8. The electrodeless discharge lamp lighting device according to claim 1, wherein the high-frequency power supply circuit includes a quartz oscillator. 9. The DC power supply circuit, the high-frequency power supply circuit,
The electrodeless discharge lamp lighting device according to any one of claims 1 to 8, further comprising a housing that houses a starting circuit and a matching switching circuit.