JPH09199286A - Starting method for electrodeless high intensity discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the influence of reflection wave energy resulting from mismatching between a power source circuit and a load, and prevent the damage of a power source device with ease by starting a lamp using pulse-like high frequency at a lamp starting time, and lighting the lamp using continuous high frequency after lamp starting. SOLUTION: In a lighting method for an electrodeless high intensity discharge lamp 6 using a high frequency power source, at a lamp 6 starting time, the output of a power amplification circuit 3 is formed into pulse-like high frequency by a puls modulation circuit 7, and the same is used. After lamp starting, the lamp 6 is lighted by a continuous high frequency. The pulse like high frequency for starting the lamp is a repetition wave composed of a high frequency segment T1 and a rest segment T2. The frequency of the high frequency segment T1 is 100Hz to 600kHz, and the duty ratio of the high frequency segment T1 to the rest segment T2 is set in a range of 1/10 to 1/3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for starting an electrodeless high-intensity discharge lamp using electrodeless discharge at high pressure.

[0002]

2. Description of the Related Art Generally, a method of applying a high frequency generated by a high frequency power source to an electrodeless discharge lamp through a load matching circuit to light the lamp is well known.

When the lamp is lit by such a method, if the lamp is one using electrodeless discharge at a low pressure, for example, an electrodeless fluorescent lamp, the starting is simple and the time required for starting is extremely short. There is little need to consider damage to the power supply due to reflected wave energy caused by the mismatch between the load and the load.

However, when the lamp uses electrodeless discharge at high pressure, for example, an electrodeless high-intensity discharge lamp, the time to start is long, about several seconds, which is caused by the mismatch between the power supply circuit and the load. The reflected wave energy may damage the power supply device, and thus parts having high resistance must be used for the power supply device, resulting in high cost.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and reduces the influence of reflected wave energy generated by the mismatch between the power supply circuit and the load by a relatively simple means. Therefore, it is possible to prevent damage to the power supply device without using parts having high resistance to the power supply device, and to provide a starting method of an electrodeless high-intensity discharge lamp that can be economically provided with a low-cost device. To do.

[0006]

In order to achieve the above object, according to the invention of claim 1, in a method of lighting an electrodeless high-intensity discharge lamp with a high frequency power supply, when starting the lamp, a pulsed high frequency is used. After starting, the lamp is lit by continuous high frequency after starting the lamp.

Further, in the invention of claim 2, the pulsed high frequency for starting the lamp is a repetitive wave of the high frequency section and the rest section, and the frequency of the high frequency section is 100 Hz to 6 Hz.
The duty ratio of the high frequency section to 00 kHz and the rest section is 1/10 to 1/3.

Further, in the invention of claim 3, a direct current source,
The high frequency generated by a high frequency power supply consisting of a high frequency oscillation circuit that converts direct current to high frequency and a power amplification circuit that amplifies high frequency energy is applied to an electrodeless high-intensity discharge lamp via a load matching circuit to light the lamp. In the method, a pulse modulation circuit is connected to the power amplification circuit, and the lamp is started by the pulsed high frequency wave generated by the pulse modulation circuit.

[0009]

1 is a block diagram showing a device for starting and lighting an electrodeless high-intensity discharge lamp according to the present invention. In the figure, 1
Is a direct current source, 2 is a high frequency oscillation circuit for converting direct current to high frequency, 3 is a power amplifier circuit for amplifying high frequency energy generated by the high frequency oscillation circuit, 4 is no amplified high frequency energy via the high frequency coil 5. A load matching circuit for applying to the electrode high-intensity discharge lamp 6 and a pulse modulation circuit 7 connected to the power amplification circuit.

In the above block diagram, specific configuration examples of the high frequency oscillation circuit 2, the power amplification circuit 3, the load matching circuit 4, and the pulse modulation circuit 7 are shown in FIGS. 4, 5 and 6, respectively. In addition, an electrodeless high-intensity discharge lamp 6
For example, in a spherical quartz bulb having a diameter of about 25 mm, about 10 mg of a metal halide such as NaI and a rare gas such as Xe are sealed at a pressure of about 13300 Pascal.
A 00 W lamp is used.

When the electrodeless high-intensity discharge lamp is started by using the above-mentioned device, the pulse modulation circuit 7 makes the output of the power amplification circuit 3 a pulsed high frequency as shown in FIG. Then, this is applied to the electrodeless high-intensity discharge lamp 6 via the load matching circuit 4 and the high-frequency coil 5. The pulsed high frequency wave in FIG. 2 is a repetitive wave of the high frequency section T ₁ and the rest section T ₂ , and the frequency of the high frequency section T ₁ is 1
The duty ratio of 00 Hz to 600 kHz and the high frequency section T ₁ with respect to the rest section T ₂ is selected in the range of 1/10 to 1/3.

If the frequency of the high-frequency section T ₁ of pulsed high frequency is less than 100 Hz, the Xe gas plasma once generated is cooled until the next high-frequency section, so that the startability is deteriorated. On the other hand, if the frequency exceeds 600 kHz, the transient loss of the resonant circuit at the beginning and end of the high frequency section cannot be ignored. Further, if the duty ratio of the high frequency section T _{1 to} the rest section T ₂ is smaller than 1/10, the temperature of the lamp will start but the temperature of the lamp will not rise so much that the time until lighting becomes long. On the contrary, 1/3
If it is larger, the heat generated in the load matching circuit increases, the resistance of the coil increases, the voltage generated at both ends of the coil decreases, and the startability deteriorates. The startability of the lamp in the lighting device is determined by the peak value of the high frequency output, but the peak value sufficient to start the lamp is:
Approximately 600 when using a 2.5 turn high frequency coil
0V.

After the lamp has been started as described above,
The lamp is kept on by a continuous high frequency as shown in FIG. The switching of the pulse modulation circuit is performed in the idle period T
_This can be done by bringing ₂ close to zero. In the case of a lamp that is difficult to start, the output in the high frequency range is set higher than the average output when the lamp is lit, so it is necessary to adjust the gain of the power amplification circuit so that the rated power is supplied to the lamp at the same time. is there.

It is also possible to provide a so-called dimming function of changing the brightness of the lamp by changing the duty ratio of the pulse modulating circuit when the lamp is turned on. Further, since the secondary circuit (secondary coil by the Xe gas discharge path) exists in the lamp, the duty ratio of the pulse modulation circuit is brought close to 1, so that electric power can be quickly supplied into the lamp. This makes it possible to instantly perform rated light emission.

[0015]

According to the present invention, when the lamp is started, it is started by the pulsed high frequency wave, and after the lamp is started, the lamp is lit by the continuous high frequency wave. Therefore, the reflection is caused by the mismatch between the power supply circuit and the load. Even if wave energy is generated, the reflected wave energy will be reduced as a whole when averaged over time, and it is not necessary to use parts with high resistance to the power supply device, so an economically low-cost device can be used. Can be provided. Further, by using the pulse modulation circuit as described above, there is an advantage that the lighting device can have a dimming function and a blinking function.

[Brief description of drawings]

FIG. 1 is a block diagram of a lighting device used in the present invention.

FIG. 2 shows a pulsed high frequency waveform applied when the lamp is started.

FIG. 3 shows a continuous high frequency waveform applied after the lamp has started.

FIG. 4 shows an example of a high-frequency oscillator circuit used in the present invention.

FIG. 5 shows an example of a power amplification circuit and a pulse modulation circuit used in the present invention.

FIG. 6 shows an example of a load matching circuit used in the present invention.

[Explanation of symbols]

1 DC source 2 High-frequency oscillation circuit 3 Power amplification circuit 4 Load matching circuit 5 High-frequency coil 6 Electrode-free high-intensity discharge lamp 7 Pulse modulation circuit T ₁ Pulse high-frequency high-frequency section T ₂ Pulse high-frequency pause section Vp High-frequency voltage peak value

Claims (3)

[Claims] 1. A method of lighting an electrodeless high-intensity discharge lamp with a high-frequency power supply, wherein when the lamp is started, it is started with a pulsed high-frequency wave, and after the lamp is started, the lamp is lit with a continuous high-frequency wave. A method for starting an electrodeless high-intensity discharge lamp, which is characterized in that: 2. The pulsed high frequency for starting the lamp is a repetitive wave of a high frequency section and a rest section, the frequency of the high frequency section is 100 Hz to 600 kHz, and the duty ratio of the high frequency section to the rest section is 1 /. 10/1 /
3. The method for starting an electrodeless discharge lamp according to claim 1, wherein the starting point is 3. 3. A high frequency generated by a high frequency power source comprising a direct current source, a high frequency oscillating circuit for converting direct current into a high frequency, and a power amplifying circuit for amplifying high frequency energy is passed through a load matching circuit to obtain electrodeless high brightness. In the method of applying a voltage to a discharge lamp to turn on the lamp, a pulse modulation circuit is connected to the power amplification circuit, and the lamp is started by a pulsed high frequency wave generated by the pulse modulation circuit. How to start a brightness discharge lamp.