JPH11111479A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device eliminating impedance mismatching resulting from the fact that the current flowing in a coaxial cable is adversely affected by a stray capacitance, capable of being stably lighted without increasing the loss of a high frequency power circuit, and capable of surely starting up the discharge lamp. SOLUTION: This device is provided with a high frequency power source circuit 7 contained in first metal case 14 and outputting high frequency power, a matching circuit 9 contained in second metal case 10 connected to the output end of the high frequency power source circuit 7 via a cable, matching impedance between an input and an output, and a load circuit 1 equipped with a discharge lamp connected to the output end of the matching circuit 9, receiving power supply from the high frequency power source circuit 7, and is lighted on. The cable is covered with a metal matter having the same potential as the first case 14 and the second case 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a discharge lamp lighting device in which a matching circuit is interposed between a high-frequency power supply circuit and a load circuit.

[0002]

2. Description of the Related Art A conventional discharge lamp lighting device is shown in FIGS.
5 will be described. FIG. 12 is a block diagram showing the configuration of the discharge lamp lighting device. FIG. 13 is a configuration diagram of the matching circuit. FIG. 14 is a circuit diagram showing a configuration example of a discharge lamp lighting device. FIG. 15 is a structural diagram of the discharge lamp lighting device.

In FIG. 12, a discharge lamp lighting device includes a high-frequency power supply circuit 7 for outputting high-frequency power and a high-frequency power supply circuit 7.
And a second matching circuit 8 that matches impedance between the input and output connected to the output terminal of the second matching circuit 8 and reduces reflection, and an input / output terminal connected to the output terminal of the second matching circuit 8 via a coaxial cable 13. It comprises a first matching circuit 9 for impedance matching and reducing reflection, and a load circuit 1. The load circuit 1 includes a high-frequency power supply coil 2 connected to the output end of the first matching circuit 9 and an inert gas, metal vapor, or the like in a glass bulb disposed close to the high-frequency power supply coil 2. And an electrodeless discharge lamp 1a in which the discharge gas is sealed.

[0004] The first matching circuit 9 and the second matching circuit 8 are an inverted-L type shown in FIG.
, The T type shown in FIG. 13C, and the lattice type shown in FIG. 13D can be used.

A specific circuit will be described with reference to FIG.
The high-frequency power supply circuit 7 includes a transmission circuit 3, a preamplifier 4, a main amplifier 5, and a filter circuit 17.
The oscillating circuit 3 is an oscillating circuit using the crystal oscillator X. A low-Q tuning circuit is formed by the coil L6 and the capacitor C15, and is an unadjusted oscillator. The preamplifier 4 is tuned to the oscillation frequency by the coil L5 and the capacitor C17, and the oscillation output of the oscillation circuit 3 is
It is configured to perform class amplification. Resistance R8 to R10
Constitutes an attenuation circuit, and the resistor R11 is connected to lower the Q of the coil L5.

The main amplifier 5 is connected to a preamplifier 4 by a power MOSFET (hereinafter referred to as a transistor) Q5 or the like.
Is further amplified by high frequency power. The coil L7 is
It is connected to cancel the input capacitance of the transistor Q5, and the resistor R12 is connected to match the input impedance of the transistor Q5 with the output of the preamplifier 4.

The filter circuit 17 includes a coil L3, a capacitor C4, and the like, and prevents a high frequency from returning to a DC power supply.

The electrodeless discharge lamp 1a has a rare gas, mercury vapor, and the like sealed therein, and a high-frequency power supply coil 2, which is an air-core coil having several turns, is located near the outer periphery of the electrodeless discharge lamp 1a. It is provided. The high-frequency power supplied from the first matching circuit 9 is supplied to the high-frequency power supply coil 2, and the electrodeless discharge lamp 1a is turned on.

The first matching circuit 9 includes a capacitor C1
9, C20 and a variable capacitor Cver. The second matching circuit 8 includes capacitors C22, C2
3. It is composed of a coil L10.

The high-frequency power supply circuit 7 has a capacitor C21 inserted therein to remove a DC component from the high-frequency output.

Next, the structure of the discharge lamp lighting device will be described. As shown in FIG. 15, the discharge lamp lighting device has a spherical electrodeless discharge lamp 1a, a high-frequency power supply coil 2 wound around the electrodeless discharge lamp 1a, and a mesh shape surrounding these. And a second metal case 10 that houses the first matching circuit 9 and is mounted on the bottom of the shield case 12, a coaxial cable 13, and a high-frequency power supply circuit 7. And a first metal case 14 in which the second matching circuit 8 is housed.

The operation of the discharge lamp lighting device configured as described above will be described below. First, a high-frequency voltage from the high-frequency power supply circuit 7 is applied to the high-frequency power supply coil 2 disposed close to and along the outer periphery of the electrodeless discharge lamp 1a. Then, the high-frequency power supply coil 2 has a frequency of several MHz to several hundred M.
When a high-frequency current of 1 Hz flows, a high-frequency magnetic field is generated in the high-frequency power supply coil 2, high-frequency power is supplied to the electrodeless discharge lamp 1 a, and a high-frequency plasma current is generated in the electrodeless discharge lamp 1 a to emit ultraviolet or It produces visible light.

[0013]

However, in the discharge lamp lighting devices shown in FIGS. 11 to 15 as described above, the first matching circuit 9 and the second matching circuit 8 are used.
Since the coaxial cable 13 interposed therebetween has a stray capacitance between itself and the ground, the current flowing through the coaxial cable 13 is adversely affected by the stray capacitance. That is, the frequency of the high frequency voltage applied to the electrodeless discharge lamp 1a is generally several MHz to several hundred MHz, and at such a high frequency, the current flowing through the coaxial cable 13 is easily affected by the stray capacitance. Has become.

Therefore, in the above-described discharge lamp lighting device, the first matching circuit 9 and the second matching circuit 8 are adversely affected by the stray capacitance, and the high-frequency power supply circuit 7 and the The impedance matching with the electric lamp 1a is deteriorated, and the reflection of electric power is increased. As a result, the loss of components used in the high-frequency power supply circuit 7 is increased, and it becomes difficult to start the electrodeless discharge lamp 1a. There is a problem that a problem of performing the operation occurs.

In particular, when the discharge lamp lighting device is housed in the lighting equipment, the coaxial cable 13 is arranged in various ways inside the lighting equipment, so that the stray capacitance between the coaxial cable 13 and the lighting equipment is more remarkable. , And the above problem is likely to occur.

The present invention has been made to solve the above problems, and an object of the present invention is to eliminate the impedance mismatch caused by the adverse effect of the stray capacitance on the current flowing through the coaxial cable. An object of the present invention is to provide a discharge lamp lighting device capable of performing stable lighting without increasing the loss of a high-frequency power supply circuit and reliably starting a discharge lamp.

[0017]

According to the present invention, there is provided a high-frequency power supply circuit for outputting high-frequency power housed in a first metal case. A matching circuit housed in a second metal case and connected to an output terminal of the high-frequency power supply circuit via a cable to match impedance between input and output, and the high-frequency power supply circuit connected to an output terminal of the matching circuit A load circuit with a discharge lamp that is lit by receiving power supply from the
, Wherein the cable is covered with a metal object having the same potential as the first metal case and the second metal case.

According to a second aspect of the present invention, the metal object is deformable.

According to a third aspect of the present invention, a high-frequency power supply circuit for outputting high-frequency power stored in a first metal case and a high-frequency power supply circuit stored in a second metal case are provided at an output end of the high-frequency power supply circuit. The matching circuit is mounted in a discharge lamp lighting device having a matching circuit connected via a cable to match impedance between input and output, and a load circuit connected to an output terminal of the matching circuit and having a discharge lamp. Wherein the circuit pattern of the printed circuit board is surrounded by a circuit pattern having the same potential as that of the second metal case.

According to a fourth aspect of the present invention, a high-frequency power supply circuit for outputting high-frequency power stored in a first metal case and a high-frequency power supply circuit stored in a second metal case are provided at an output end of the high-frequency power supply circuit. A discharge lamp lighting device comprising: a matching circuit connected via a cable to match impedance between input and output; and a load circuit connected to an output terminal of the matching circuit and including a discharge lamp. A discharge lamp lighting device, wherein a circuit pattern of a printed circuit board to be mounted is surrounded by a circuit pattern having the same potential as a first metal case.

According to a fifth aspect of the present invention, one end of the cable is attached to a non-mounting surface of a printed circuit board on which the high-frequency power supply circuit is mounted.

According to a sixth aspect of the present invention, the other end of the cable is attached to a non-mounting surface of a printed circuit board on which the matching circuit is mounted.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a discharge lamp lighting device according to the present invention is shown in FIGS. 1 and 2, a second embodiment is shown in FIGS. Based on FIGS. 5 and 6, the fourth embodiment is based on FIG. 7, the fifth embodiment is based on FIGS. 8 and 9, and the sixth embodiment is based on FIG. A seventh embodiment will be described with reference to FIG.

[First Embodiment] FIG. 1 is a circuit diagram showing a configuration example of a discharge lamp lighting device. FIG. 2 is a sectional view of the coaxial cable. In FIG. 1, the same parts as those of the discharge lamp lighting device described in the above-described conventional technique are denoted by the same reference numerals, and the detailed description of the same parts will be omitted.

The discharge lamp lighting apparatus of the present embodiment shown in FIG. 1 is different from the discharge lamp lighting apparatus described in the prior art described above in the following features.

That is, the coaxial cable described in the prior art is covered with a metal having the same potential as the first metal case 14 and the second metal case 10 to form a coaxial cable 18.

More specifically, as shown in FIG.
8a and a first insulator 18b covering the first conductor 18a
A second conductor 18c covering the first insulator 18b, a second insulator 18d covering the second conductor 18c, and a third conductor 18e having plasticity covering the second insulator 18d;
The coaxial cable 18 is constituted by the third insulator 18f covering the third conductor 18e. And the first conductor 1
8a and the second conductor 18c are connected to the second matching circuit 8 at points A and B in FIG. 1, and connected to the first matching circuit 9 at points A 'and B'. The third conductor 18e is connected to the first metal case 14 at point C, and is connected to the second metal case 10 at point C '. The third conductor 18e has the same potential as the first metal case 14 and the second metal case 10.

In the discharge lamp lighting device having the above configuration,
Even if the discharge lamp lighting device is housed in a lighting fixture, the third conductor 18e of the coaxial cable 18 is set to the same potential as the first metal case 14 and the second metal case 10 to reduce the electric influence from the surroundings. Therefore, impedance mismatch between the high-frequency power supply circuit 7 and the electrodeless discharge lamp 1a is unlikely to occur.

Further, since the third conductor 18e has plasticity, the first metal case 14 and the second metal case 10 are required when the discharge lamp lighting device is housed in a lighting fixture.
Can be disposed at desired positions, and the coaxial cable 18 can be freely pulled and arranged.

[Second Embodiment] FIG. 3 is a circuit diagram showing a configuration example of a discharge lamp lighting device. FIG. 4 is a sectional view of the coaxial cable. In FIG. 3, the same parts as those of the discharge lamp lighting device described in the above-described conventional technique are denoted by the same reference numerals, and the detailed description of the same parts will be omitted.

The discharge lamp lighting device according to the present embodiment shown in FIG. 3 is different from the discharge lamp lighting device described in the above-mentioned prior art and has the following features.

That is, the aluminum foil 19 or the copper foil 19 ′ is wound around the coaxial cable 13 so as to cover the outer skin of the coaxial cable 13. The aluminum foil 19 or copper foil 19 '
Has one end connected to the first metal case 14,
The other end is connected to the second metal case 10.

Therefore, the aluminum foil 19 or the copper foil 19 'has the same potential as the first metal case 14 and the second metal case 10.

In the discharge lamp lighting device having the above configuration,
Even if the discharge lamp lighting device is housed in a lighting fixture, the aluminum foil 19 or the copper foil 19 ′ is set to the same potential as the first metal case 14 and the second metal case 10 and is affected by the surroundings. Therefore, impedance mismatch between the high-frequency power supply circuit 7 and the electrodeless discharge lamp 1a is less likely to occur.

[Third Embodiment] FIG. 5 is a circuit diagram showing a configuration example of a discharge lamp lighting device. FIG. 6 is a sectional view of the coaxial cable. In FIG. 5, the same reference numerals are given to the same parts as those of the discharge lamp lighting device described in the above-described conventional technique, and the detailed description of the same parts will be omitted.

The discharge lamp lighting device according to the present embodiment shown in FIG. 3 is different from the discharge lamp lighting device described in the above-mentioned prior art in that it has the following features.

That is, the configuration is such that the coaxial cable 13 is inserted into the pipe 20 and the outer cover of the coaxial cable 13 is covered by the pipe 20. The pipe 20 is formed of a conductive material such as iron, and has one end connected to the first metal case 14 and the other end connected to the second metal case 10.

Therefore, the pipe 20 is the first metal case 1
It has the same potential as the fourth and second metal cases 10.

In the discharge lamp lighting device having the above configuration,
Even when the discharge lamp lighting device is housed in a lighting fixture, the pipe 20 is made to have the same potential as the first metal case 14 and the second metal case 10 and is less susceptible to electric influence from the surroundings. Power supply circuit 7 and electrodeless discharge lamp 1
The impedance mismatch with respect to “a” hardly occurs.

[Fourth Embodiment] FIG. 7 is a circuit diagram showing a configuration example of a discharge lamp lighting device. In FIG. 7, the same parts as those of the discharge lamp lighting device described in the above-described conventional technique are denoted by the same reference numerals, and detailed description of the same parts will be omitted.

The discharge lamp lighting device according to the present embodiment shown in FIG. 7 is different from the discharge lamp lighting device described in the above-mentioned prior art and has the following features.

That is, without providing the second matching circuit 8,
Further, the coaxial cable 13 is inserted through a flexible tube 21 having flexibility, and the flexible tube 21 is inserted.
With this configuration, the outer skin of the coaxial cable 13 is covered. The flexible tube 21 is formed of a conductive material, and has one end connected to the first metal case 14 and the other end connected to the second metal case 10.

Accordingly, the flexible tube 21 has the same potential as the first metal case 14 and the second metal case 10.

In the discharge lamp lighting device having the above configuration,
Even if this discharge lamp lighting device is housed in a lighting fixture, the flexible tube 21 is made to have the same potential as the first metal case 14 and the second metal case 10 and is less susceptible to electric influence from the surroundings. Impedance mismatch between the high-frequency power supply circuit 7 and the electrodeless discharge lamp 1a is less likely to occur.

[Fifth Embodiment] FIG. 8 is a circuit diagram showing a configuration example of a discharge lamp lighting device. FIG. 9 is a plan view showing a circuit pattern of a printed circuit board on which the first matching circuit is mounted. In FIG. 8, the same parts as those of the discharge lamp lighting device described in the first embodiment are denoted by the same reference numerals, and the detailed description of the same parts will be omitted.

The discharge lamp lighting device of the present embodiment shown in FIG. 8 is different from the discharge lamp lighting device described in the first embodiment in the following features.

That is, first, the first matching circuit 9 is of a π type constituted by capacitors C19, C20 and C25, and the ground side of the first matching circuit 9 and the second metal case 10 are connected by a capacitor C24. It is a connected configuration.

Second, as shown in FIG. 9, the circuit pattern P1 of the first matching circuit 9 on the printed circuit board 22 on which the first matching circuit 9 is mounted is replaced with the second metal case 1.
This is a configuration surrounded by a circuit pattern P2 having the same potential as 0.

In the discharge lamp lighting device having the above configuration,
First conductor 18a and second conductor 1 of coaxial cable 18
Since the connection point between the first matching circuit 8c and the first matching circuit 9 is surrounded by the circuit pattern P2, the connection point is less susceptible to electrical influences from the surroundings, and the higher frequency power supply circuit 7 and the electrodeless discharge lamp 1a And the impedance mismatch between them is hard to occur.

[Sixth Embodiment] FIG. 10 is a plan view showing a circuit pattern of a printed circuit board on which a second matching circuit is mounted. In FIG. 10, the same parts as those of the discharge lamp lighting device described in the first embodiment are denoted by the same reference numerals, and the detailed description of the same parts will be omitted.

The discharge lamp lighting device of the present embodiment shown in FIG. 10 is different from the discharge lamp lighting device described in the first embodiment in the following features.

That is, as shown in FIG. 10, the high-frequency power supply circuit on which the high-frequency power supply circuit and the second matching circuit 8 are mounted and the circuit pattern P3 of the second matching circuit 8 are connected to the first metal case. 14 is surrounded by a circuit pattern P4 having the same potential as that of the circuit pattern P14.

In the discharge lamp lighting device having the above configuration,
First conductor 18a and second conductor 1 of coaxial cable 18
Since the connection point between the second matching circuit 8c and the second matching circuit 8 is surrounded by the circuit pattern P4, the connection point is hardly affected by the surroundings, and the high frequency power supply circuit 7 and the electrodeless discharge lamp 1a And the impedance mismatch between them is hard to occur.

FIG. 11 is a side view of a printed circuit board of a discharge lamp lighting device. In FIG. 11, the same parts as those of the discharge lamp lighting device described in the above-described conventional technique are denoted by the same reference numerals, and the detailed description of the same parts will be omitted.

The discharge lamp lighting apparatus according to the present embodiment shown in FIG. 11 is different from the discharge lamp lighting apparatus described in the above-mentioned conventional technique in that it has the following features.

That is, one end of the coaxial cable 13 is attached to the non-mounting surface 23a of the printed circuit board 23 on which the high-frequency power supply circuit 7 and the second matching circuit 8 are mounted.

According to this configuration, there is an effect that adverse effects on other electronic components due to noise generated from a connection portion between the coaxial cable 13 and the second matching circuit 8 and the high-frequency power supply circuit 7 can be minimized.

In this embodiment, the coaxial cable 1
3 is attached to the non-mounting surface 23a of the printed circuit board 23, but the other end of the coaxial cable 13 is connected to the non-mounting surface 22a of the printed circuit board 22 on which the first matching circuit 9 is mounted. It may be attached to.

[0059]

Since the discharge lamp lighting device of the present invention is constructed as described above, according to the first aspect of the present invention, the cable has the same potential as the first metal case and the second metal case. Since the current flowing through the coaxial cable is adversely affected by stray capacitance, impedance mismatch is less likely to occur, and stable lighting can be performed without increasing the loss of the high-frequency power supply circuit. This has the effect that the discharge lamp can be started quickly.

According to the second aspect of the present invention, since the metal object is deformable, the degree of freedom in the arrangement of the high-frequency power supply circuit and the load circuit is increased when the discharge lamp lighting device is housed in a lighting fixture. The effect that it can be made to play is produced.

According to the third aspect of the present invention, since the circuit pattern of the printed circuit board on which the matching circuit is mounted is surrounded by a circuit pattern having the same potential as the second metal case, the printed circuit board on which the matching circuit is mounted is mounted. The connection point between the circuit pattern and the cable is less susceptible to electrical influences from the surroundings, and has the effect of making it more difficult for impedance mismatching to occur.

According to the fourth aspect of the present invention, since the circuit pattern of the printed circuit board on which the high-frequency power supply circuit is mounted is surrounded by a circuit pattern having the same potential as that of the first metal case, the printed circuit on which the high-frequency power supply circuit is mounted is provided. The connection point between the circuit pattern of the board and the cable is less susceptible to electrical influences from the surroundings, and has the effect of making it more difficult to cause impedance mismatching.

According to the fifth aspect of the present invention, since one end of the cable is attached to the non-mounting surface of the printed circuit board on which the high-frequency power supply circuit is mounted, the cable is generated from the connection between the cable and the high-frequency power supply circuit. This has the effect of minimizing adverse effects on other electronic components due to noise.

In the invention according to claim 6, since the other end of the cable is attached to the non-mounting surface of the printed circuit board on which the matching circuit is mounted, the cable is generated from a connection portion between the cable and the matching circuit. This has the effect of minimizing adverse effects on other electronic components due to noise.

[Brief description of the drawings]

FIG. 1 is a circuit diagram illustrating a configuration example of a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a coaxial cable.

FIG. 3 is a circuit diagram illustrating a configuration example of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a coaxial cable.

FIG. 5 is a circuit diagram showing a configuration example of a discharge lamp lighting device according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a coaxial cable.

FIG. 7 is a circuit diagram illustrating a configuration example of a discharge lamp lighting device according to a fourth embodiment of the present invention.

FIG. 8 is a circuit diagram illustrating a configuration example of a discharge lamp lighting device according to a fifth embodiment of the present invention.

FIG. 9 is a plan view showing a circuit pattern of a printed circuit board on which a first matching circuit is mounted.

FIG. 10 is a plan view illustrating a circuit pattern of a printed circuit board on which a second matching circuit according to a sixth embodiment of the present invention is mounted.

FIG. 11 is a side view of a printed circuit board of a discharge lamp lighting device according to a seventh embodiment of the present invention.

FIG. 12 is a block diagram showing a configuration of a conventional discharge lamp lighting device.

FIG. 13 is a configuration diagram of a matching circuit.

FIG. 14 is a circuit diagram illustrating a configuration example of a discharge lamp lighting device.

FIG. 15 is a structural diagram of a discharge lamp lighting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Load circuit 1a Discharge lamp 7 High frequency power supply circuit 9 Matching circuit 10 Second metal case 13 Cable 14 First metal case 18 Cable 18e Metal object 22 Printed circuit board 23 Printed circuit board P1 Circuit pattern P2 Circuit pattern P3 Circuit pattern P4 Circuit pattern

Claims (6)

[Claims] A high-frequency power supply circuit for outputting high-frequency power stored in a first metal case; and a high-frequency power supply circuit stored in a second metal case and connected to an output terminal of the high-frequency power supply circuit via a cable for input / output. A discharge lamp lighting device, comprising: a matching circuit that matches impedance between the two; and a load circuit that is connected to an output terminal of the matching circuit and has a discharge lamp that receives power from the high-frequency power supply circuit and lights. Is covered with a metal object having the same potential as the first metal case and the second metal case. 2. The discharge lamp lighting device according to claim 1, wherein the metal object is deformable. 3. A high-frequency power supply circuit for outputting high-frequency power stored in a first metal case, and a high-frequency power supply circuit stored in a second metal case and connected to an output terminal of the high-frequency power supply circuit via a cable to input and output. A discharge lamp lighting device having a matching circuit for matching impedance between the two, and a load circuit connected to an output terminal of the matching circuit and having a discharge lamp. A discharge lamp lighting device, which is surrounded by a circuit pattern having the same potential as that of the metal case. 4. A high-frequency power supply circuit for outputting high-frequency power stored in a first metal case, and a high-frequency power supply circuit stored in a second metal case and connected to an output terminal of the high-frequency power supply circuit via a cable for input / output. A discharge lamp lighting device comprising: a matching circuit for matching impedance between the matching circuit; and a load circuit having a discharge lamp connected to an output terminal of the matching circuit. A discharge lamp lighting device, which is surrounded by a circuit pattern having the same potential as one metal case. 5. The discharge lamp lighting device according to claim 1, wherein one end of the cable is attached to a non-mounting surface of a printed circuit board on which the high-frequency power supply circuit is mounted. . 6. The discharge lamp lighting device according to claim 1, wherein the other end of the cable is attached to a non-mounting surface of a printed circuit board on which the matching circuit is mounted. .