JPH06310291A - Electrodeless discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To provide an electrodeless discharge lamp lighting device which can transmit high-frequency power efficiently even if load condition changes. CONSTITUTION:A high-frequency power supply coil 2 is connected between the output terminals of a high frequency power supply 7, and an electrodeless discharge lamp, where discharge gas such as inert gas, metallic steam, or the like is charged in a glass bulb, is arranged in the vicinity of the high-frequency power supply coil 2, and a first impedance rectifying circuit 9 is connected between the high frequency power supply 7 and the high frequency power supply coil 2. And, a coaxial cable 13 is interposed between the high-frequency power supply 7 and the abovementioned first impedance rectifying circuit 9, and a second impedance rectifying circuit 8 is interposed between this coaxial cable 13 and the above-mentioned high-frequency power supply 7.

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 which emits light by applying a high frequency electromagnetic field to an electrodeless discharge lamp.

[0002]

2. Description of the Related Art Conventionally, an electrodeless discharge lamp lighting device of this kind, which emits light by applying a high-frequency electromagnetic field to an electrodeless discharge lamp, is connected between output terminals of a high-frequency power source 7, as shown in FIG. The high frequency power supply coil 2 and an inert gas in a glass bulb which is arranged in the vicinity of the high frequency power supply coil 2;
An electrodeless discharge lamp 1 filled with a discharge gas such as metal vapor,
The impedance matching circuit section 6 is connected between the high frequency power source 7 and the high frequency power supply coil 2 to achieve impedance matching and reduce reflection.

The operating state will be briefly described below. A high-frequency voltage from the high-frequency power source 7 is applied to the high-frequency power supply coil 2 that is arranged in proximity along the spherical outer circumference of the electrodeless discharge lamp 3. Then, several MH is applied to the high frequency power supply coil 2.
By passing a high frequency current of several hundred MHz from z,
A high-frequency electromagnetic field is generated in the high-frequency power supply coil 2,
High frequency power is supplied to the electrodeless discharge lamp 1
A high frequency plasma current is generated in the inside to generate ultraviolet rays or visible light.

FIG. 6 shows a specific structure of such a conventional example. The high frequency power supply 7 is composed of an oscillation circuit 3, a preamplifier 4, a main amplifier 5 and a filter circuit 17. The oscillating circuit 3 is an oscillating circuit using a crystal oscillator X, and a low-Q tuning circuit is formed by the coil L6 and the capacitor C15 to provide an unadjusted oscillator. The preamplifier 4 is configured to tune the oscillation frequency by the coil L5 and the capacitor C17, and amplify the oscillation output of the oscillation circuit 3 in the class C by the transistor Q4. Resistance R
The circuit composed of 8 to R10 constitutes an attenuator, and the resistor R1
1 is connected to lower the Q of the coil L5.

The main amplifier 5 is a power MOSFET.
The output of the preamplifier 4 is further high frequency power amplified by Q5 (hereinafter referred to as a transistor). Coil L
7 is connected to cancel the input capacitance of the transistor Q5, and the resistor R12 is connected to the transistor Q5.
5 are connected to match the input impedance of 5 with the output of preamplifier 4. The filter circuit 17 is composed of a coil L3, a capacitor C4, etc., and prevents a high frequency from returning to the DC power supply.

The electrodeless discharge lamp 1 is one in which a rare gas, mercury vapor and the like are enclosed, and the electrodeless discharge lamp 1 has an air-core coil of several turns on the outer periphery thereof for supplying high frequency power. The coil 2 is provided close to the coil 2, and the high frequency power input from the impedance matching circuit unit 6 is supplied to the coil 2. The luminous gas in the electrodeless discharge lamp 1 is driven by magnetic induction.

The impedance matching circuit 6 is composed of capacitors C18 to C20, etc., and outputs the output of the main amplifier 5 and the electrodeless discharge lamp 1 and the high frequency power supply coil 2 in the subsequent stage.
And impedance matching with.

FIG. 7 (a) is a side view of a conventional electrodeless discharge lamp lighting device, and FIG. 7 (b) is a plan view. Here, the outer case 11 of the apparatus houses a high frequency power supply 7 and an impedance matching circuit 6 inside. The shield case 12 has a mesh shape to prevent noise emitted from the electrodeless discharge lamp 1. This mesh shape is set based on the relationship between the noise prevention effect and the rate of decrease in light output due to the light being shielded.

FIG. 8 shows a conventional example in which a coaxial cable is used. Between the main amplifier 5 and the electrodeless discharge lamp 1, a coaxial cable 13 is connected to both ends of an output transistor Q5 having a relatively low voltage. The reason is,
It is conceivable to connect the coaxial cable 13 to both ends of the capacitor C20 and the variable capacitor Cver of the impedance matching circuit 6, but the voltage across the high frequency power supply coil 2 is the output transistor Q5 of the main amplifier 5.
This is because there is a problem in that the shape of the coaxial cable 13 becomes large because the voltage is higher than the voltage across both ends. In particular, when the electrodeless discharge lamp 1 is started, the voltage across the high frequency power supply coil 2 becomes high. The capacitors connected to both ends of the output transistor Q5 may be connected to the main amplifier 5 side like the capacitor C21 or may be connected to the electrodeless discharge lamp 1 side like the capacitor C18.

[0010]

As described above, in the conventional example in which the coaxial cable is not used, the heat generated by the electrodeless discharge lamp is transmitted to other electronic components in the vicinity, and the temperature rise of the electronic components becomes high. However, since problems such as a decrease in reliability and light emission efficiency occur, problems occur in terms of cost and shape, such as considering a structure that is easily cooled or adopting a large rated electronic component.

Further, in the conventional example using the coaxial cable, since impedance matching is not performed between the main amplifier and the coaxial cable, power reflection occurs and the high frequency power of the high frequency power source is electrodeless. There is a problem that it cannot be efficiently transmitted to the discharge lamp. In order to prevent this, it is necessary to adjust each capacitor by changing the capacitor Cver of the impedance matching circuit for each electrodeless discharge lamp and coaxial cable.

It is an object of the present invention to provide an electrodeless discharge lamp lighting device capable of efficiently transmitting high frequency power even when the load state changes.

[0013]

SUMMARY OF THE INVENTION The present invention is directed to a high frequency power supply coil connected between output terminals of a high frequency power supply, and an inert gas or metal in a glass bulb disposed in the vicinity of the high frequency power supply coil. Lighting of an electrodeless discharge lamp comprising an electrodeless discharge lamp filled with a discharge gas such as steam, and a first impedance matching circuit section connected between the high frequency power supply and the high frequency power supply coil In the apparatus, a coaxial cable inserted between the high frequency power supply and the first impedance matching circuit section, and a second impedance connected between the coaxial cable and the high frequency power supply. And a matching circuit section.

[0014]

According to the present invention, the coaxial cable inserted between the high frequency power source and the first impedance matching circuit section and the second coaxial cable connected between the coaxial cable and the high frequency power source are provided. Since the impedance matching circuit is configured, the coaxial cable can be used, and the electrodeless discharge lamp side, which is the load, and the main amplifier side, which is the high frequency power supply, can be configured separately, and thermal effects can be avoided. And a load side unit including a first impedance matching circuit section and an electrodeless discharge lamp,
Since the impedance matching circuit section and the high-frequency power supply-side unit including the main amplifier can be adjusted for impedance matching separately, any combination of the high-frequency power-supply-side unit and the load-side unit becomes possible, and This has the effect of eliminating the need for troublesome adjustments.

[0015]

FIG. 1 is a block diagram showing an embodiment of the present invention. 5 is different from the conventional example shown in FIG. 5 in that the first impedance matching circuit section 9 is interposed between the coaxial cable 13 and the high frequency power supply coil 2, and the high frequency power supply 7 is provided. The second impedance matching circuit section 8 is interposed between the coaxial cable 13 and the coaxial cable 13. Note that the same portions are denoted by the same reference numerals, and duplicate description will be omitted.

Here, the first impedance matching circuit unit 9 and the second impedance matching circuit unit 8 are shown in FIG.
Any matching circuit as shown in (a), (b), (c) and (d) can be used. FIG. 2A shows an inverted L-type matching circuit,
2B shows a π-type matching circuit, FIG. 2C shows a T-type matching circuit, and FIG. 2D shows a lattice-type matching circuit.

Further, FIG. 3 shows a concrete circuit diagram. Note that the same portions are denoted by the same reference numerals, and duplicate description will be omitted. Here, an example is shown in which the first impedance matching circuit unit 9 uses an inverse L-type matching circuit and the second impedance matching circuit unit 8 uses a Π-type matching circuit. The capacitor C21 of the high frequency power supply 7 is inserted to remove the DC component from the high frequency output.

Further, FIG. 4 shows a structural diagram as an electrodeless discharge lamp lighting device. The electrodeless discharge lamp 1, the high frequency power supply coil 2 wound around the electrodeless discharge lamp 1, the shield case 12 surrounding them, and the load side containing and housing the first impedance matching circuit section 9. Unit 1
0, the high frequency power supply 7 and the second impedance matching circuit section 8 are included and housed in the high frequency power supply side unit 1
4 and a coaxial cable 13.

With this configuration, the coaxial cable
It is possible to use the bull 13 and the electrodeless discharge lamp 1 which is a load.
Side and the main amplifier 5 side, which is the high frequency power supply 7, can be configured separately to prevent thermal influence, and also the load side unit 10 including the first impedance matching circuit section 9 and the electrodeless discharge lamp 1. And the second impedance matching circuit section 8
Since the impedance matching can be adjusted separately for the high frequency power supply 7 side unit 14 including the main amplifier 5, the high frequency power supply 7 side unit 14 and the load 1 side unit 1
This has the effect that any combination with 0 can be made possible and the troublesome adjustment of each item becomes unnecessary.

The input impedance of the load side unit 10 and the output impedance of the high frequency power source side unit 14 are also provided.
By making the dance and the characteristic impedance of the coaxial cable 13 substantially coincide with each other, high-frequency power can be efficiently supplied to the electrodeless discharge lamp 1.

[0021]

According to the present invention, a high-frequency power supply coil connected between output terminals of a high-frequency power supply and a glass bulb disposed in the vicinity of the high-frequency power supply coil are used to discharge an inert gas, a metal vapor or the like. An electrodeless discharge lamp lighting device comprising: an electrodeless discharge lamp filled with gas; and a first impedance matching circuit section connected between the high frequency power supply and the high frequency power supply coil. A coaxial cable inserted between the high frequency power source and the first impedance matching circuit section, and a second impedance matching circuit section connected between the coaxial cable and the high frequency power source. Since it is configured, the coaxial cable can be used, and the electrodeless discharge lamp side that is the load and the main amplifier side that is the high frequency power source can be configured separately, and thermal influence can be prevented and 1 Impey A load-side unit including a Nsu matching circuit portion and an electrodeless discharge lamp, the second Inpi - dance matching circuit and a high frequency power source side unit and each separately Inpi comprising main amplifier - so enabling adjustment of dance matching,
The high-frequency power supply side unit and the load side unit can be arbitrarily combined with each other, and the remarkable effect that the troublesome adjustment of each item is unnecessary.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is an example of a matching circuit showing an embodiment of the present invention.

FIG. 3 is a specific circuit diagram showing an embodiment of the present invention.

FIG. 4 is a structural diagram showing an embodiment of the present invention.

FIG. 5 is a block diagram showing a conventional example of the present invention.

FIG. 6 is a specific circuit diagram showing a conventional example of the present invention.

FIG. 7 is a structural diagram showing a conventional example of the present invention.

FIG. 8 is a specific circuit diagram showing a conventional example of the present invention.

[Explanation of symbols]

 1 Electrodeless discharge lamp 2 High frequency power supply coil 7 High frequency power supply 8 First impedance matching circuit section 9 First impedance matching circuit section 13 Coaxial cable

Claims (2)

[Claims] 1. A high-frequency power supply, a high-frequency power supply coil connected between output terminals of the high-frequency power supply, and an inert gas, metal vapor, or the like in a glass bulb arranged in the vicinity of the high-frequency power supply coil. In an electrodeless discharge lamp lighting device comprising an electrodeless discharge lamp filled with a discharge gas, and a first impedance matching circuit section connected between the high frequency power supply and the high frequency power supply coil, A coaxial cable inserted between the high frequency power source and the first impedance matching circuit section, and a second impedance matching circuit section connected between the coaxial cable and the high frequency power source. An electrodeless discharge lamp lighting device comprising: 2. The first and second impedance matching circuit sections include an input impedance on the electrodeless discharge lamp side as seen from the coaxial cable and an output impedance on the coaxial cable side as seen from the high frequency power source side. 2. The electrodeless discharge lamp lighting device according to claim 1, wherein the characteristic impedance of the coaxial cable and the characteristic impedance of the coaxial cable are substantially matched.