JPH07320884A - Lighting device for electrodeless electric discharge lamp, lighting device for the lamp and lighting device using the lamp - Google Patents

Abstract

PURPOSE:To restrain the occurrence of a jamming radio wave and prevent the breakdown of an element by selecting one of a stationary oscillation means and a voltage control oscillation means, depending on the output of a voltage or current detection means. CONSTITUTION:One of output signals from a crystal oscillator 1 and a voltage control oscillator 3 is selected by a switch 4, and sent to a power amplifier 5. This amplifier 5 has a switching element for switching operation, and the output thereof is fed to an electrodeless electric discharge lamp 7 via a coupling means 6. This lighting device is provided with a selector means 9, and this means 9 controls the switch 4 in response to an output signal from a detection means 2. Namely, when control voltage outputted from the means 2 agrees to the preset voltage value, then, the means 9 controls the switch 4 for the selection thereof at the oscillator 1. Also, when the control voltage outputted from the means 2 is different from the preset value, the means 9 controls the switch 4 for the selection thereof at the oscillator 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for lighting an electrodeless discharge lamp and an electrodeless discharge lamp lighting device using the lighting device.

[0002]

2. Description of the Related Art Conventionally, a lighting device for lighting an electrodeless discharge lamp receives an output of a frequency fixed oscillator such as a crystal oscillator and operates a switching element of an inverter.
The output of this inverter is supplied to an excitation coil or the like that is magnetically coupled to an electrodeless discharge lamp, and the discharge lamp is called, for example, the ISM band (industrial / scientific and medical frequency) 1
It was configured to illuminate in the frequency band around 3.56 MHz.

Since the above lighting device performs a switching operation by receiving a fixed frequency, the frequency related to the output is stable and the oscillation frequency falls within the required frequency range. Therefore, it has an excellent feature that an interfering radio wave is not output in a frequency band used in radio communication or the like.

However, according to the above-mentioned lighting device, the frequency characteristics of the electrodeless discharge lamp having the inductance or capacitance component change, for example, when the discharge lamp is started,
Alternatively, the impedances of the lighting device and the discharge lamp do not match due to changes due to changes over time, and the phase relationship between the voltage and current output from the lighting device changes.

Particularly, in the case of an electrodeless discharge lamp, mega Hz
Since it is excited by an electromagnetic wave having a short wavelength such as a band, its impedance characteristic becomes steep, and if the above impedance mismatch occurs, the luminous efficiency is, of course, lowered, and in the worst case, There is a problem that a large amount of reactive current flows and the elements of the lighting device are destroyed.

Therefore, the inventors of the present invention have filed Japanese Patent Application No. 4-172.
As shown in No. 100, the invention invented a device that detects a phase difference between a current and a voltage output from a lighting device and changes a lighting frequency so as to keep the phase difference constant.

According to this, there is an advantage that the generation of interfering radio waves can be suppressed to a level that does not cause a problem, and the element can be prevented from being destroyed by appropriately responding to the frequency fluctuation of the electrodeless discharge lamp.

[0008]

However, in the above, circuit components such as a current detector, a voltage detector, and a phase comparator are indispensable, so that the circuit configuration tends to be complicated.

The present invention has been made in order to solve the above-mentioned conventional problems, and an object thereof is to suppress the generation of interfering radio waves to a level that does not pose a problem with a simple circuit configuration, and An object of the present invention is to provide a lighting device for an electrodeless discharge lamp, which can prevent damage to the element by appropriately responding to changes in the frequency characteristics of the electrode discharge lamp, and an electrodeless discharge lamp lighting device using the same.

[0010]

A lighting device for an electrodeless discharge lamp according to claim 1 oscillates at a fixed oscillating means oscillating at a fixed frequency and at a frequency different from the frequency oscillated by the fixed oscillating means. Second oscillating means, fixed oscillating means, and power amplifying means capable of amplifying the output of the second oscillating means,
Coupling means for supplying the output of the power amplifying means to the electrodeless discharge lamp, detection means for detecting a voltage or current according to the power supplied to the coupling means, and fixed oscillation means or a first oscillating means depending on the output of the detecting means. And selecting means for selecting one of the outputs of the oscillating means and supplying it to the power amplifying means.

The electrodeless discharge lamp lighting device according to claim 2 is
An electrodeless discharge lamp lighting device according to claim 1 and an electrodeless discharge lamp activated by an output of the electrodeless discharge lamp lighting device.

A lighting device for an electrodeless discharge lamp according to a third aspect of the present invention includes an oscillating means capable of oscillating at a plurality of frequencies, a power amplifying means for amplifying an output supplied from the oscillating means, and an output of the power amplifying means. The oscillating means transiently oscillates the oscillation frequency according to the output of the detecting means, and the connecting means supplies the electrode discharge lamp and the detecting means for detecting the voltage or the current according to the electric power supplied to the connecting means. It is characterized in that it is configured to change.

An electrodeless discharge lamp lighting device according to a fourth aspect of the present invention is an electrodeless discharge lamp lighting device according to the third aspect, and an electrodeless discharge lamp energized by the output of the electrodeless discharge lamp lighting device. An electrodeless discharge electrodeless discharge lamp lighting device, comprising:

An electrodeless discharge lamp lighting device according to claim 5 is
A fixed oscillating means for oscillating at a fixed frequency, a second oscillating means for oscillating at a frequency different from the frequency oscillated by the fixed oscillating means, and an output supplied from the fixed oscillating means and the second oscillating means. Possible power amplification means, coupling means for radiating electromagnetic waves to the output of the power amplification means, detection means for detecting voltage or current according to the power supplied to the coupling means, and fixed according to the output of the detection means Selection means for selecting either the output of the oscillating means or the second oscillating means and supplying it to the power amplifying means, the electrodeless discharge lamp that emits light by the output of the coupling means, and the emission of the electrodeless discharge lamp is reflected or transmitted. And a light control means for emitting the light to the outside.

The electrodeless discharge lamp lighting device according to claim 6 is:
Oscillating means for oscillating at a plurality of frequencies, power amplifying means for amplifying the output supplied from the oscillating means, coupling means for radiating electromagnetic waves from the output of the power amplifying means, and voltage according to the power supplied to the coupling means. Alternatively, the control means for outputting to the oscillating means a signal capable of transiently changing the oscillation frequency of the oscillating means based on the current, the electrodeless discharge lamp which emits light by the output of the coupling means, and the emission of the electrodeless discharge lamp is reflected or transmitted. And a light control means for emitting the light to the outside.

Here, in the above description, transiently changing the oscillation frequency means changing the oscillation frequency to a frequency different from a substantially steady state.

Here, in the above description, the light control means for reflecting or transmitting the light emitted from the electrodeless discharge lamp and radiating it outward is typically, for example, emitted from the discharge lamp in order to obtain a desired light distribution. A reflective member such as a reflector or a louver that reflects light, a so-called optical filter or an optical interference member that changes the spectral characteristics, and a translucent member that transmits substantially all the light without changing the spectral characteristics. Collectively.

[0018]

In the electrodeless discharge lamp, the impedance characteristics of the electrodeless discharge lamp greatly change, for example, in a state before starting lighting and in a stable lighting state. Therefore, when power is supplied from the lighting device, it responds to the impedance change. The voltage or current changes. That is, in the state before the start of lighting,
The impedance of the discharge lamp is substantially infinite, while the impedance of the discharge lamp after the start of lighting is small, so that the Q of the equivalent circuit including the discharge lamp as a load at the start of starting is lowered. . Therefore,
At the start of starting the discharge lamp, the voltage of the electric power supplied from the lighting device drops. Further, if the impedances of the electrodeless discharge lamp and the lighting device are not matched, the Q of the equivalent circuit including the discharge lamp as a load changes as described above, and the voltage or current also changes. .

According to the present invention, the detecting means detects the voltage or the current associated with the variation of the impedance characteristics without detecting the phase difference between the current and the voltage which complicates the circuit, and outputs the output of the detecting means. Accordingly, the selection means or the frequency control means changes the oscillation frequency supplied to the power amplifier. Then, since the electrodeless discharge lamp is a load having an impedance or capacitance component, the impedance changes according to the frequency of the power supplied, and the impedance mismatch between the lighting device and the discharge lamp can be improved. become.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows configurations of an electrodeless discharge lamp lighting device and an electrodeless discharge lamp lighting device according to an embodiment of the present invention.

In this embodiment, a crystal oscillator 1 that oscillates at a frequency fixed to 13.56 MHz and a voltage controlled oscillator (VCO) 3 that oscillates at a frequency according to the control voltage output from the detection means 2 are provided. Has been. One of the outputs of the crystal oscillator 1 and the voltage controlled oscillator 3 is selected by the switch 4 and is given to the power amplifier 5. The power amplifier 5 includes a switching element, receives an oscillation output, and is switched, and the output is supplied to the electrodeless discharge lamp 7 via a coupling means 6 configured of, for example, an excitation coil.

A voltage pickup unit 8 is provided on the line from the power amplifier 5 to the coupling means 6, and the power amplifier 5
A voltage corresponding to the voltage supplied to the coupling means 6 is taken out from. Then, the extracted voltage is given to the detecting means 2 and used for detecting the impedance variation of the electrodeless discharge lamp 7 magnetically coupled to the coupling means 6. That is, when the impedance characteristic of the electrodeless discharge lamp 7 changes, the voltage amount of the power related to the output of the power amplifier 5 changes due to the deviation of the matching state. Therefore, the detecting means 2 detects the change in the voltage amount and outputs the control voltage according to the result. Specifically, for example, when the detected voltage exceeds a predetermined voltage value, the voltage controlled oscillator 3
On the other hand, a level that oscillates a frequency of 15 MHz, which is higher than that of the crystal oscillator 1, is output, and as the detected voltage approaches the predetermined voltage value, the control voltage is transited to lower the oscillation frequency.

Further, the lighting device is provided with selecting means 9, which inputs the output of the detecting means 2 and controls the switch 4 in response to the output of the detecting means 2. . That is, when the control voltage output from the detection means 2 matches a predetermined voltage value, the switch 4 is controlled to switch to the crystal oscillator 1 side, and the control voltage output from the detection means 2 is set to the predetermined voltage. When the voltage value is different from the voltage value of, the switch 4 is controlled to be switched to the voltage controlled oscillator 3 side so that one output of each of the oscillators 1 and 3 is supplied to the power amplifier 5.

By the above operation, when there is an impedance mismatch between the lighting device and the electrodeless discharge lamp, the power of the frequency corresponding to the voltage detected by the detection means is supplied to the lighting device and the discharge device. The impedance mismatch with the electric lamp can be improved. It should be noted that such an operation is for a short time such as when the electrodeless discharge lamp is started, and even if an interfering radio wave is generated, its influence on the radio wave communication or the like is almost negligible.

Further, when the matching is maintained, since the power of the fixed frequency is supplied, it is possible to suppress the interference wave which is an advantage of the oscillation at the fixed frequency. Next, a lighting device according to another embodiment of the present invention will be described with reference to FIG. Here, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, a high-pass filter 10 for detecting a transient change in the power supplied to the coupling means 6 is provided, and only when there is a transient change in the voltage extracted by the voltage pickup unit 8. In addition, the voltage signal is input to the detection means 2.

When the voltage signal input through the high-pass filter 10 is zero, the detecting means 2 controls the voltage-controlled oscillator 3 so that the voltage-controlled oscillator 3 oscillates at a predetermined fixed frequency, for example, 13.56 MHz. When a voltage signal is given through the high pass filter 10, a control voltage that raises the oscillation frequency of the voltage controlled oscillator 3 is output according to the voltage signal. That is, the voltage-controlled oscillator 3 as the oscillating means is configured to transiently change its oscillation frequency according to the output of the detecting means 2.

With the above configuration, when the impedance of the electrodeless discharge lamp 7 largely changes transiently, the oscillation frequency is changed by the voltage controlled oscillator 3 to cause impedance mismatch between the lighting device and the discharge lamp. When the electrodeless discharge lamp 7 is stably lit and the impedances are matched, it is possible to suppress the interfering radio waves, similarly to the fixed oscillating means in the above embodiment.

Next, an embodiment of the electrodeless discharge lamp lighting device of the present invention will be described with reference to FIGS. That is, in the present embodiment, the electrodeless discharge lamp 7 includes an electrodeless discharge lamp body 7a in which a light-emitting metal such as krypton gas and sodium iodide is hermetically sealed in a hollow quartz glass sphere.
The starting thin tube 7b made of a tubular glass tube is joined to the above. When the discharge lamp 7 is started, a high voltage is applied to the starting thin tube 7b to cause glow discharge and plasma is induced in the discharge lamp main body 7a, so that the discharge lamp main body 7a emits lighting power as electromagnetic waves. Electric power is supplied from the excitation coil 6 as a coupling means to the starter circuit configured by connecting the coil L1, the capacitor C2, and the resistor R1 in parallel via the capacitor C1.
The excitation coil 6 is arranged so as to surround the discharge lamp main body 7a, and is formed by integrally forming a conductive metal such as aluminum into a coil shape so as to be wound two to three turns. Further, the switch SW indicates a switch for activation.

530 pF from the excitation coil 6 to the power supply side
A capacitor Cp and a capacitor Cs having a certain capacity are connected so as to form a T circuit and function as a matching circuit. A connection point of a pair of field effect transistors (FET) T1 and T2 for switching and one transistor T
The output of the power amplifier 5 from between the two sources is supplied to the excitation coil 6 as the coupling means via the matching circuit. Source of transistor T1 and transistor T2
A power supply voltage VDD is applied to the drains of the transistors, and a high frequency for switching is supplied from the driver 11 to the gates of the transistors T1 and T2.

Further, in this embodiment, the excitation coil 6
The voltage supplied to is taken in by dividing the drain-source voltage of the transistor T1 by the capacitors C3 and C4. The voltage taken in from the detection end 8 is output to the control means 14 including a high pass filter 10, a comparator 12 and a low pass filter 13. That is, the high-pass filter 1 is the same as in the above embodiment.
The output of the high pass filter 10 is input to one terminal of the comparator 12 via 0 when the voltage transiently changes. A DC voltage corresponding to the normal operation of the electrodeless discharge lamp 7 is applied to the other terminal of the comparator 12 as a reference voltage VREF.

The output of the comparator 12 is given to the low-pass filter 13, and this low-pass filter 13
The output of the comparator 12 is integrated to create a DC voltage signal.
Then, this DC voltage signal is configured to be supplied to the voltage controlled oscillator 3 as a control voltage.
Further, here, the control means 14 controls the high-pass filter 10
When the voltage signal input via the is zero, a DC voltage signal is output so that the voltage controlled oscillator 3 oscillates at a predetermined fixed frequency of, for example, 13.56 MHz, and is output via the high-pass filter 10. When a voltage signal is applied, a DC voltage signal that raises the oscillation frequency of the voltage controlled oscillator 3 according to the voltage signal is output. That is, the control means 14 controls the excitation coil 6
The oscillation frequency of the voltage controlled oscillator 3 is transiently changed based on the voltage corresponding to the power output to the electrodeless discharge lamp 7
When is lit stably, a DC voltage signal is output so that the oscillation frequency is fixed.

A light control means for reflecting or transmitting the light emitted from the electrodeless discharge lamp and radiating it outward will be described with reference to FIG. As shown in the main part of the figure, the socket 15 for supporting the discharge lamp 7 by mechanically fixing the starting thin tube 7b of the electrodeless discharge lamp 7 has a bowl-shaped reflecting shade whose inner surface exhibits a reflecting surface. It is attached to the center of 16. In addition, a front glass plate 17 having a metal mesh (not shown) embedded therein is disposed in the opening of the reflection shade 16 in order to prevent electromagnetic waves from leaking to the outside. The front glass plate 17 constitutes a light control means.

Next, the operation of the electrodeless discharge lamp lighting device configured as described above will be described focusing on the lighting device portion. When the switch SW is closed, power is supplied to the resonance circuit including the capacitor C2, the coil L1, and the resistor R1 via the capacitor C1 to cause resonance. The resonance power is supplied to the starting thin tube 7b attached to the electrodeless discharge lamp 7 to cause glow discharge. This glow discharge, together with the electromagnetic wave radiation from the excitation coil 6 to the electrodeless discharge lamp 7, induces a plasma discharge of the electrodeless discharge lamp 7, and ring-shaped plasma is generated to reach a starting state.

The impedance characteristic of the electrodeless discharge lamp 7 changes from the start to the lighting of the electrodeless discharge lamp 7, and accordingly, the drain-source voltage of the transistor T1 is divided by the voltage dividing capacitor C3. The voltage divided by C4 and taken in varies. Then, the voltage taken in from the detection end 8 is passed through the high-pass filter 10, and when the voltage transiently changes, the high-pass filter 1
The output of the high-pass filter 10 is input to one terminal of the comparator 12, and the reference voltage VRE corresponding to when the electrodeless discharge lamp 7 operates normally is input.
Compared to F. Further, the output of the comparator 12 is given to the low pass filter 13, and the low pass filter 1
3 integrates the output of the comparator 12 to create a DC voltage signal, and this DC voltage signal is supplied to the voltage controlled oscillator 3 as a control voltage. Therefore, when the impedance of the electrodeless discharge lamp 7 does not change, the voltage signal input through the high-pass filter 10 is zero, so that the control unit 14 sets a predetermined value, for example, 13.56.
A DC voltage signal is output so that the voltage controlled oscillator 3 oscillates at a frequency fixed to MHz. In addition, the electrodeless discharge lamp 7
When a transitional impedance fluctuation occurs at the time of starting, etc., a voltage signal is given through the high-pass filter 10, and a DC voltage that raises the oscillation frequency of the voltage controlled oscillator 3 according to the voltage signal. Acts to output a signal. That is, the control means 14 transiently changes the oscillation frequency of the voltage-controlled oscillator 3 based on the voltage corresponding to the power output to the excitation coil, and when the electrodeless discharge lamp 7 is stably lit, its oscillation is generated. A DC voltage signal is output so that the frequency is fixed.

As described above, when the impedance of the electrodeless discharge lamp fluctuates transiently, the voltage controlled oscillator changes the oscillation frequency to suppress the impedance mismatch between the lighting device and the discharge lamp. Thus, when the electrodeless discharge lamp is stably lit and the impedances are matched, it is possible to suppress the interfering radio waves as in the fixed oscillating means.

In the above-mentioned embodiment, the one in which the voltage supplied to the coupling means is detected or the oscillating means is controlled based on the voltage is specifically described.
A current detection unit may be provided in the current path reaching the coupling unit to detect the current, and similarly the oscillation unit may be controlled based on the current.

Further, in the above, the coupling means and the power amplifier are connected by an extension cable having a fixed characteristic impedance such as a coaxial cable to separate the electric circuit portion and the lamp portion including the electrodeless discharge lamp. You can also In this case, the circuit constant of the matching circuit composed of the capacitor Cp and the capacitor Cs may be changed so as to match the characteristic impedance of the cable. Specifically, for example, the capacitor C
An auxiliary capacitor may be connected in parallel to each of p and the capacitor Cs via a switch to control ON / OFF of the switch. Furthermore, the starting time or lighting state of the discharge lamp may be detected by existing means, and the circuit constant of the matching circuit may be changed according to the operating state of the discharge lamp.

[0038]

As described above, according to the present invention, the generation of interfering radio waves can be suppressed to a degree that does not pose a problem with a simple circuit structure, and the frequency characteristics of the electrodeless discharge lamp can be accurately adjusted. Accordingly, it is possible to provide an electrodeless discharge lamp lighting device, an electrodeless discharge lamp lighting device and an electrodeless discharge lamp lighting device using the same, which are capable of preventing element destruction.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing an embodiment of a lighting device for an electrodeless discharge lamp and a lighting device for an electrodeless discharge lamp according to the present invention.

FIG. 2 is a circuit block diagram showing another embodiment of the lighting device for an electrodeless discharge lamp according to the present invention.

FIG. 3 is a diagram showing a circuit of an embodiment of the electrodeless discharge lamp lighting device of the present invention.

FIG. 4 is a schematic view showing a light control means of an embodiment of the electrodeless discharge lamp lighting device of the present invention.

[Explanation of symbols]

1 Crystal Oscillator (Fixed Oscillation Means) 2 Detecting Means 3 Voltage Controlled Oscillator 5 Power Amplifier 6 Coupling Means, Excitation Coil 7 Electrode Discharge Lamp 9 Selection Means 14 Control Means 16 Reflector Shade (Light Control Means) 17 Front Glass (Light Control Means) )

Claims (6)

[Claims] 1. Fixed oscillating means oscillating at a fixed frequency; second oscillating means oscillating at a frequency different from the frequency oscillated by the fixed oscillating means; fixed oscillating means and second
Power amplifying means capable of amplifying the output of the oscillating means; coupling means for supplying the output of the power amplifying means to the electrodeless discharge lamp; and detecting means for detecting a voltage or current according to the power supplied to the coupling means. A selection means for selecting either the fixed oscillation means or the output of the second oscillation means according to the output of the detection means and supplying it to the power amplification means; Lighting device for electric lights. 2. An electrodeless discharge lamp lighting device according to claim 1, and an electrodeless discharge lamp which is energized by an output of the electrodeless discharge lamp lighting device. Electrode discharge lamp lighting device. 3. Oscillation means capable of oscillating at a plurality of frequencies; power amplification means for amplifying an output supplied from the oscillation means;
A coupling means for supplying the output of the power amplification means to the electrodeless discharge lamp; a detection means for detecting a voltage or a current according to the power supplied to the coupling means; and the oscillation means according to the output of the detection means. A lighting device for an electrodeless discharge lamp, which is configured to transiently change the oscillation frequency. 4. An electrodeless discharge lamp lighting device according to claim 3, and an electrodeless discharge lamp which is energized by an output of the electrodeless discharge lamp lighting device. Electrode discharge lamp lighting device. 5. Fixed oscillating means oscillating at a fixed frequency; second oscillating means oscillating at a frequency different from the frequency oscillated by the fixed oscillating means; fixed oscillating means and second
Power amplifying means capable of amplifying the output supplied from the oscillating means; coupling means for radiating an electromagnetic wave from the output of the power amplifying means; and detecting means for detecting a voltage or current according to the power supplied to the coupling means. Selecting means for selecting either the fixed oscillating means or the output of the second oscillating means for supply to the power amplifying means according to the output of the detecting means; and an electrodeless discharge lamp that emits light by the output of the coupling means; An electrodeless discharge lamp lighting device, comprising: a light control unit that reflects or transmits the light emitted from the electrodeless discharge lamp and emits the light outward. 6. Oscillating means for oscillating at a plurality of frequencies; power amplifying means for amplifying an output supplied from the oscillating means; coupling means for radiating an electromagnetic wave from an output of the power amplifying means; Control means for outputting to the oscillating means a signal capable of transiently changing the oscillating frequency of the oscillating means based on voltage or current according to the electric power; electrodeless discharge lamp emitting light by the output of the coupling means; An electrodeless discharge lamp illuminating device comprising: a light control means for reflecting or transmitting emitted light and radiating it outward.