JPH06111972A - Electrodeless discharge lamp lighting device - Google Patents

Abstract

(57) [Abstract] [Purpose] To enable good setting of high frequency power supply, lamp load and matching. [Configuration] The load impedance deviation angle viewed from the inverter is (1) the phase angle rises sharply from negative to positive in the vicinity of the operating point, (2) the operating point is set in the slope of this rising, ( 3) The phase of the operating point is positive, (4) There is a dip in the higher frequency part from the above slope,
(5) The operating frequency at the start is set so as to satisfy the condition that the slope of the slope at the operating point is positive.
In addition, tuning is performed with respect to the operating frequency so that the deflection angle of the load impedance viewed from the inverter at the time of start-up satisfies the above five conditions.

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 lighting a lamp by magnetically supplying high frequency power to a plasma ring in the lamp from an excitation coil wound around the electrodeless discharge lamp. In particular, the present invention relates to a device capable of favorably performing impedance matching between a high frequency power supply and a lamp load at the time of starting.

[0002]

2. Description of the Related Art Electrodeless discharge lamps have high efficiency, high brightness,
It is a discharge lamp that has excellent characteristics such as high color rendering and long life. However, in order to efficiently transmit the high frequency power to the excitation means, for example, the excitation coil, the network for performing matching or the like must be set to have extremely low loss and high Q. There is a difficulty that the fluctuation of the response is extremely large. In order to solve this, there is a lighting device having a closed loop system capable of detecting the phases of the load current and the load voltage and controlling the operating frequency (the output frequency of the inverter) so that the phase value becomes an appropriate value. In such a closed loop system, the phase angle of the output can be made constant, so that the element can be protected if it is set in a safe region for the element that constitutes the high frequency power supply section.

[0003]

However, there is no known method for setting the above phase angle. As a result, problems such as insufficient protection of the closed loop system and insufficient supply of power to the lamp may occur.

The present invention has been proposed in order to solve the problems of the above-mentioned conventional techniques, and in particular, the operating point can be set so as to ensure the operational stability at the time of starting. An object of the present invention is to provide an electrodeless discharge lamp lighting device.

[0005]

In order to achieve this object, in the present invention, the deviation angle of the load impedance seen from the inverter is (1) the phase angle rises from negative to positive in the vicinity of the operating point. (2) The operating point is set during this rising slope, (3) the phase of the operating point is positive, (4) there is a dip in the higher frequency part from the above slope, (5) at the operating point The slope of the above slope of is positive,
The operating frequency at the time of start is set so as to satisfy the condition. In addition, tuning is performed with respect to the operating frequency so that the deflection angle of the load impedance viewed from the inverter at the time of start-up satisfies the above five conditions.

The present invention will be specifically described below. When the excitation coil is used as a load, a capacitor 4 is connected in series to the excitation coil 3 as shown in FIG. 1 in order to cancel out the reactance and make the impedance low with respect to the high frequency power source. Furthermore, the capacitor 5 may be connected in parallel to the excitation coil 3, or an inductor, a transformer, or a capacitor may be connected in addition to the excitation coil 3. However, the phase angle of the impedance of the main circuit seen from the inverter as a whole near the operating frequency is zero. You should have. The starting circuit 7 is connected in parallel to the excitation coil 3 or the inverter 1. As long as the starting circuit 7 is operated at a high frequency, the starting circuit 7 cannot be purely resistive and becomes a two-terminal network including an inductance and a capacitance. Similarly, the impedance phase angle must have a zero point. Here, the problems are the zero point of the phase angle of the main circuit and the starting circuit 7 and the relative position of the operating frequency. If the zero point of the main circuit is fixed and the zero point of the starting circuit is gradually shifted, there are four cases shown in (A) to (D) of FIG. In the present invention, the case of (D) is used. How to select the operating frequency (operating phase) for this case (D) will be described with reference to FIG. In the figure, the operating conditions from (1) to (6) satisfy the following conditions only in the case of (3). Condition (1) A sufficient coil current is secured near the zero point of the main circuit. (2) Since it is near the zero point of the starting circuit 7, sufficient electric power can be supplied to the starting circuit 7. However, the starting circuit 7 can be damped,
If this is done, the distance between the zero point and the operating frequency can be made large. (3) The phase curve has a positive slope. (4) The phase angle is positive.

[0007]

EXAMPLE A specific example of the electrodeless discharge lamp lighting device according to the present invention will be described below with reference to FIG. In this embodiment, the phases of the output current and the output voltage of the inverter detected by the phase detector are supplied to the oscillator circuit so that an appropriate operating frequency can be set. Moreover, each circuit constant is shown in FIG. The frequency range is 13.0 MHz to 13.7 MHz.

[0008]

As described above, according to the present invention, a method of setting the impedance phase of the main circuit and the starting circuit seen from the inverter is clarified, and the starting circuit can be operated stably at the time of starting, and it is sufficient. The starting power can be supplied to the lamp.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a basic electrodeless discharge lamp lighting device according to the present invention.

FIG. 2 is a circuit diagram showing a configuration of a specific electrodeless discharge lamp lighting device.

FIG. 3 is a diagram showing circuit constants of the lighting device of FIG.

FIG. 4 is a diagram showing a resonance characteristic curve when the zero point of the phase angle of the starting circuit is shifted.

FIG. 5 is a diagram showing a resonance characteristic curve and an operating point used in the present invention.

[Explanation of symbols]

 1 Inverter 2 Oscillation Circuit 3 Excitation Coil 4 Series Capacitor 5 Parallel Capacitor 7 Starting Circuit 8 Lamp 9 Starting Switch 10 Phase Detector

Claims (5)

[Claims] 1. An inverter for converting a DC power source into a high frequency power source, an electrodeless discharge lamp in which at least a discharge gas or vapor is sealed in a lamp tube, and an excitation coil disposed near the lamp tube or in the lamp tube. A series resonance capacitor that is inserted in series with respect to the excitation coil connected between the output terminals of the inverter, and a series resonance capacitor that is connected between the output terminals of the inverter or in parallel with the excitation coil, and at least a series resonance circuit. In the electrodeless discharge lamp lighting device having a starting circuit for applying a high voltage for starting to the electrodeless discharge lamp when the lamp is started, the deviation angle of the load impedance seen from the inverter is:
(1) The phase angle rapidly rises from negative to positive near the operating point,
(2) The operating point is set during this rising slope,
(3) The phase of the operating point is positive, (4) there is a dip in the higher frequency part from the slope, and (5) the slope of the slope at the operating point is positive. An electrodeless discharge lamp lighting device characterized by setting an operating frequency at the time of starting. 2. An inverter for converting a DC power source into a high frequency power source, an electrodeless discharge lamp in which at least a discharge gas or vapor is sealed in a lamp tube, and an excitation coil arranged near the lamp tube or in the lamp tube. And a series resonance capacitor that is inserted in series with respect to the excitation coil connected between the output terminals of the inverter, and is connected between the output terminals of the inverter or in parallel with the excitation coil and at least a series resonance circuit. And a starting circuit for applying a high voltage for starting to the electrodeless discharge lamp at the time of starting the lamp, in the electrodeless discharge lamp lighting device, the deviation angle of the load impedance seen from the inverter at the time of starting is (1) The phase angle rapidly rises from negative to positive near the operating point. (2) The operating point is set during this rising slope. , (3) the phase of the operating point is a positive, there is a dip in the portion higher further frequencies from (4) above the slope,
(5) An electrodeless discharge lamp lighting device characterized in that tuning is performed with respect to an operating frequency so as to satisfy the condition that the slope of the slope at the operating point is positive. 3. An operating point satisfying the above condition is detected from a load current and a load voltage, and a feedback loop is formed so that the phase becomes a specified value. 2. The electrodeless discharge lamp lighting device according to 2. 4. The electrodeless discharge lamp lighting device according to claim 4, wherein the control operation in the feedback loop lowers the operating frequency when the phase is larger than a specified value and raises the operating frequency when the phase is smaller than the specified value. . 5. The electrodeless discharge lamp lighting device according to claim 3, wherein the operating frequency range is limited so that the operating point does not exist on the positive slope side of the dip.