JPH08315992A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE: To suppress the evaporation and scattering of an electrode and extend the lamp life by supplying a substantially rectangular wave lamp current to a high-pressure discharge lamp at a frequency selected within a range between about 1kHz and about 100kHz. CONSTITUTION: A lighting circuit formed of a DC power source 103, a full-bridge inverter circuit 14, and a starting circuit 15 has such a constitution that transistors 117, 120 and transistors 118, 119 are alternately ON/OFF according to the output signal of a driving circuit 220 to invert the output of a step-down chopper circuit 116 into alternating current, and a rectangular wave lamp current of 4kHz is supplied to a metal halide lamp 210. Thus, the peak value of arc temperature near an electrode which changes timewise is minimized, and the sputtering by positive ion of a cathode is also suppressed. Consequently, the evaporation and scattering of the electrode can be suppressed to suppress the blackening of the lamp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device for lighting a high pressure discharge lamp.

[0002]

2. Description of the Related Art High-pressure discharge lamps that utilize a rare gas such as mercury or argon gas, and a metal halide added to them, and then seal it in a translucent container such as quartz glass to discharge the light are highly efficient. It has characteristics such as brightness and high efficiency, and is widely used for general lighting as well as for overhead projectors, overhead type projection televisions, and projectors. Conventionally, this high-pressure discharge lamp is generally lit by a lighting device that supplies a sin-shaped waveform of a commercial power supply frequency or a rectangular-wave lamp current of a low frequency (several 100 Hz). Such a conventional discharge lamp lighting device is described in No. There is one described in 10. This discharge lamp lighting device will be described in detail with reference to FIG.

FIG. 7 is a basic block diagram of the conventional discharge lamp lighting device. In FIG. 7, 101 is a metal halide lamp which is a high pressure discharge lamp, and 102 is a lighting circuit for starting and lighting the metal halide lamp 101. The lighting circuit 102 includes a DC power supply 103, a full bridge inverter circuit 104 which is an inverter circuit, and a starting circuit 105. The DC power supply 103 receives a commercial AC power supply 106, a rectifying / smoothing circuit 107 that rectifies and smoothes the output of the commercial AC power supply 106, and converts the output to a DC, and outputs the output of the rectifying / smoothing circuit 107 to the metal halide lamp 101.
Transistor 10 for controlling the power supplied to the transistor to a predetermined value
8, the diode 109, the choke coil 110, the capacitor 111, the resistors 112, 113 and 114, and the control circuit 1
15 and the step-down chopper circuit 116, which is composed of resistors 112 and 113.
Output voltage is detected by the resistor 114, the output current is detected by the resistor 114, two detection signals are calculated by the control circuit 115, and the output signal of the control circuit 115 is used so that the output power of the step-down chopper circuit 116 becomes a predetermined value. The transistor 108 is controlled to be turned on / off. At this time, the step-down chopper circuit 116 outputs a predetermined DC voltage. FIG. 8 shows an output voltage waveform of the step-down chopper circuit 116.

The full-bridge inverter circuit 104 is composed of transistors 117, 118, 119 and 120 and a drive circuit 121, and the transistors 117 and 120 and the transistor 1 are output according to the output signal of the drive circuit 121.
Since the output of the step-down chopper circuit 116 is converted into alternating current by alternately turning on and off 18, 18 and 119, as shown in FIG.
The rectangular voltage waveform whose absolute value does not change with time is output from the full-bridge inverter circuit 104. The starting circuit 105 also generates a high-voltage pulse for starting the metal halide lamp 101.

With the above configuration, the starting circuit 105
High-voltage pulse generated from the metal halide lamp 101
Is applied to the metal halide lamp 101,
Metal halide lamp 1 detected by resistors 112 and 113
The signal proportional to the lamp voltage 01 and the signal proportional to the lamp current of the metal halide lamp 101 detected by the resistor 114 are calculated by the control circuit 115, and the metal halide lamp 1
01 is turned on / off so that the power supplied to 01 becomes a predetermined lamp power, and a predetermined DC voltage is output from the step-down chopper circuit 116. The output of the step-down chopper circuit 116 is input to the full-bridge inverter circuit 104 to convert it into a rectangular AC waveform, and the metal halide lamp 101 is supplied with a rectangular lamp current and keeps lighting. The frequency of the alternating current converted by the full bridge inverter circuit 104 is set to 400 Hz.

[0006]

However, in the above-mentioned conventional configuration, when a low-frequency rectangular wave lamp current whose absolute value of the lamp current does not change during the period is supplied to the lamp to be lit, it operates as an anode. At the electrode, it is heated by the collision of accelerated electrons and becomes high temperature, and the evaporation of the electrode is severe,
Further, in the electrode operating as the cathode, the scattering of the electrode is intense due to the collision of positive ions, and as a result, there is a problem that the blackening progresses in the early life of the lamp.

Further, when the lamp current of a sinusoidal waveform is supplied to the high-pressure discharge lamp for lighting, the absolute value of the lamp current changes during the cycle (that is, the crest factor is 1 or more), so the peak value of the electrode temperature is high. However, there is a drawback in that the electrodes are heavily consumed and the arc tube is blackened early in the life of the lamp.

When a high-voltage discharge lamp is lit at a high frequency by a lighting circuit having a starting circuit composed of a pulse transformer connected in series to the high-pressure discharge lamp, the inductance component of the pulse transformer distorts the lamp current waveform, resulting in wave efficiency. Is larger than 1, and as a result, the peak value of the electrode temperature is high, and the arc tube is blackened early in the lamp life.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a discharge lamp lighting device which suppresses evaporation and scattering of electrodes to suppress blackening of the arc tube and prolongs lamp life. .

[0010]

In order to achieve the above-mentioned object, the present invention comprises a high pressure discharge lamp and a lighting circuit for supplying a predetermined lamp current to the high pressure discharge lamp.
The lighting circuit is configured to supply a substantially rectangular wave lamp current at a frequency selected between Hz and about 100 KHz. The high-pressure discharge lamp is filled with Kr gas or Xe gas as a starting rare gas.

Further, at least a lighting circuit is provided between the DC power supply, an inverter circuit connected to the output end of the DC power supply and converting the DC output of the DC power supply into AC, and between the output end of the inverter circuit and the metal halide lamp. It consists of a starting circuit for starting a metal halide lamp, and the starting circuit consists of a pulse transformer whose secondary winding is connected in series with the high-voltage discharge lamp, and a high-voltage discharge lamp at both ends of the primary winding of the pulse transformer. It is configured to short-circuit while it is lit.

[0012]

With the above structure, the present invention makes it possible to suppress the peak value of the arc temperature near the electrode, which changes with time, to a low level, and thus to suppress the rise in the electrode temperature, and also as an anode which is subject to electron collision. Since the operating period is short, the rise in electrode temperature can be suppressed. Since positive ions are much heavier than electrons, the response becomes slow when driven between 1 KHz and 100 KHz, an ion cloud is formed between the electrodes, and sputtering due to positive ions at the cathode is suppressed. As a result, the evaporation and scattering of the electrodes are suppressed and the blackening of the arc tube of the high pressure discharge lamp is suppressed.

Further, Kr gas or Xe gas is enclosed as a starting rare gas, and the starting rare gas is about 1 KHz and about 100 KHz.
If the lighting frequency is selected to be in the range between, the electrode spatter is suppressed, and during lighting of the lamp, the electrode where heavy Kr gas or Xe gas is mainly scattered from the electrode is the wall of the arc tube. It acts as an obstacle to move to and prevents blackening of the arc tube.

In a starting circuit having a pulse transformer in which a secondary winding is connected in series with a high pressure discharge lamp, both ends of the primary winding of the pulse transformer are short-circuited while the high pressure discharge lamp is lit. As a result, the inductance value converted to the secondary side of the pulse transformer decreases,
The lamp current waveform is not distorted due to the influence of the inductance component of the pulse transformer even at a lighting frequency in the range of Hz and about 100 KHz, and therefore a rectangular wave lamp current can be supplied to the high-pressure discharge lamp.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, a first embodiment will be described with reference to FIGS. 1, 2, 3, 4, and 5. FIG. 1 is a circuit diagram showing a configuration of a discharge lamp lighting device according to a first embodiment of the present invention.

In FIG. 1, 210 is an internal volume of 0.8 cc,
It is a 200W metal halide lamp with a main electrode made of tungsten with a diameter of 0.7mm and a diameter of 0.7mm.
200 Torr of Ar gas and 30 mg of mercury, 3 mg of dysprosium iodide, 3 mg of neodymium iodide and 3 mg of cesium iodide were enclosed as a luminescent substance. Again 3
Reference numeral 01 is a lighting circuit for starting and lighting the metal halide lamp 210, which is composed of a DC power supply 103, a full-bridge inverter circuit 14 which is an inverter circuit, and a starting circuit 15 which generates a high-voltage pulse for starting the metal halide lamp 210. ing.

The starting circuit 15 is a metal halide lamp 21.
Discharge gap 2 that starts discharge at a predetermined voltage slightly lower than the voltage output from the DC power supply 103 before 0 starts lighting
02, a resistor 201, a pulse transformer 204, and capacitors 203 and 205. The secondary winding 204b of the pulse transformer 204 is a metal halide lamp 2
10 are connected in series. The series circuit and the capacitor 205 are connected in parallel to the output terminal of the full bridge inverter circuit 14. Further pulse transformer 2
The primary winding 204a of 04 is connected in series with the discharge gap 202, and this series circuit is connected in parallel with the capacitor 203.
The output voltage of the DC power supply 103 is charged via 01. Therefore, when the discharge gap 202 starts discharging, the voltage charged in the capacitor 203 is applied to the primary winding 204a of the pulse transformer 204,
The high-voltage pulse voltage boosted by the pulse transformer 204 is output from the secondary winding 204b of the pulse transformer 204 and applied to the metal halide lamp 210 via the capacitor 205.

The full bridge inverter circuit 14 is composed of transistors 117, 118, 119 and 120 and a drive circuit 220. Drive circuit 220
Is a transistor 117 so that the frequency of the alternating current output from the full-bridge inverter circuit 14 is 4 KHz.
The configuration is such that the 120 and the transistors 118 and 119 are alternately turned on and off. Other configurations are the same as those in FIG.

The operation of this embodiment configured as described above will be described. First, the output of the rectifying / smoothing circuit 107 is input to the step-down chopper circuit 116, and when the transistor 108 is turned on, the capacitor 111 is charged via the transistor 108 and the choke coil 110. Also, the transistor 10
When 8 is turned off, the choke coil 110 tries to keep the current flowing, so that the choke coil 110 and the capacitor 1
11, a current flows through the path of the diode 109 and charges the capacitor 111. The on / off operation of the transistor 108 is controlled by the control circuit 115 and the transistor 1
08 is turned on / off to output a predetermined DC voltage to the output terminal of the step-down chopper circuit 116.

First, before the metal halide lamp 210 starts lighting, the predetermined voltage is a step-down chopper circuit 116.
Is output by the full-bridge inverter circuit 14 and converted into an alternating current having a frequency of 4 KHz, and a voltage is applied to the metal halide lamp 210. At the same time, the capacitor 203 of the starting circuit 15 is charged with the output voltage of the DC power supply 103 via the resistor 201. Capacitor 203
When the charging voltage of reaches a predetermined value (the voltage value at which the discharge gap 202 starts discharging), the discharge gap 202 starts discharging. As a result, the voltage charged in the capacitor 203 is applied to the primary winding 204a, the high-voltage pulse voltage boosted by the pulse transformer 204 is output from the secondary winding 204b of the pulse transformer 204, and the metal halide lamp via the capacitor 205. Applied to 210.

After that, when the metal halide lamp 210 starts lighting, a lamp current flows, so that the resistance 112,
The transistor 108 is turned on / off in response to an output signal from the control circuit 115 which calculates a signal proportional to the lamp voltage of the metal halide lamp 210 detected by 113 and a signal proportional to the lamp current of the metal halide lamp 210 detected by the resistor 114. Controlled, step-down chopper circuit 11
The output voltage of 6 drops. As a result, the charging voltage of the capacitor 203 of the starting circuit 15 is also reduced and the discharge gap 20
2 is no longer discharged, the application of the high voltage pulse to the metal halide lamp 210 is stopped, and the lamp startup is completed.

After the starter circuit 15 stops operating, the signal and resistance proportional to the lamp voltage of the metal halide lamp 210 detected by the resistors 112 and 113 are set so that the power supplied to the metal halide lamp 210 becomes a predetermined lamp power. The transistor 108 is on / off controlled by the output signal of the control circuit 115 that calculates a signal proportional to the lamp current of the metal halide lamp 210 detected by 114, and a predetermined DC voltage is output from the step-down chopper circuit 116. The DC voltage is converted into an AC waveform with a frequency of 4 KHz by the full bridge inverter circuit 14,
The metal halide lamp 210 receives the lamp current and keeps lighting. FIG. 2 shows a lamp current waveform when the metal halide lamp 210 is lit with the configuration of FIG. The waveform is distorted to some extent by the inductance component of the pulse transformer 204, but the lamp current waveform becomes almost a rectangular wave.

Next, the result of measuring the light output characteristics by lighting the metal halide lamp 210 with the configuration of the discharge lamp lighting device of FIG. 1 will be described with reference to FIG. FIG. 3 (a) is shown in FIG.
Showing the waveform of the emission spectrum (output voltage of the photomultiplier tube) and the lamp current waveform of the emission spectrum of the mercury atom in the front surface of the electrode when the metal halide lamp 210 is lit up with a rectangular wave of 4 KHz in the above configuration. Is. Further, FIG. 3B is a diagram showing, for comparison, a light output waveform and a lamp current waveform of a light emission spectrum of a mercury atom having a wavelength of 577 nm when the metal halide lamp 210 is lit with a conventional 400 Hz rectangular wave. As shown in FIG. 3A, in the discharge lamp lighting device of this embodiment, almost no temporal change in light output was observed. However, as shown in FIG. 3 (b), in the case of square wave lighting with a conventional frequency of 400 Hz,
It can be seen that the light output pulsates and has a larger peak value Vp than the light output when a rectangular wave with a frequency of 4 KHz is lit.
Since the emission intensity of mercury atoms depends on the arc temperature, this result means that in the discharge lamp lighting device of the present embodiment, the arc temperature on the front surface of the electrode is lower than in the case of rectangular wave lighting with a frequency of 400 Hz. If the arc temperature on the front surface of the electrode is low, the temperature of the electrode affected by the arc temperature is also low. Therefore, the electrode temperature of the metal halide lamp 210 can be kept low in the discharge lamp lighting device of the present embodiment.

Next, the result of a life test performed by lighting the metal halide lamp 210 with the configuration of the discharge lamp lighting device of FIG. 1 will be described. FIG. 4 is a diagram showing changes in the luminous flux maintenance factor of the metal halide lamp 210 with respect to the lighting time when the metal halide lamp 210 is lit with a rectangular wave of 4 KHz in the configuration of FIG. Conventional 4 for comparison
The change in the luminous flux maintenance factor when the metal halide lamp 210 is turned on with a rectangular wave of 00 Hz is also added. As is clear from FIG. 4, when the conventional low frequency rectangular wave of 400 Hz is lit, the luminous flux maintenance factor of the metal halide lamp 210 becomes 50% or less after about 3000 hours, but the 4 KHz of the configuration of FIG. When the metal halide lamp 210 is lit by the rectangular wave of, the luminous flux of 70% or more is maintained even after 3000 hours have passed. Even by visual observation, the metal halide lamp 210, which was obviously lit with a rectangular wave of 4 KHz, had much less blackening.

As described above with reference to FIG. 3, the result is that the discharge lamp lighting device of this embodiment has a high frequency of 4 KHz,
The peak value of the arc temperature near the electrodes, which changes with time, can be kept low, so the electrode temperature is kept low, and the period of operation as an anode that receives electron collisions is short, and at the same time, between the electrodes. This is because the positive ions are captured and the sputtering due to the positive ions at the cathode is suppressed. Therefore, as is clear from the result of the life test, when the metal halide lamp 210 is lit with a rectangular wave of 4 KHz by the configuration of the discharge lamp lighting device of FIG. 1, the scattering and evaporation of the electrodes are suppressed and the metal halide lamp 210 is suppressed.
Blackening is suppressed and the life is greatly improved.

In the present embodiment, the metal halide lamp 210 is described as an example of a discharge lamp lighting device that lights up with a rectangular wave having a frequency of 4 KHz.
If the frequency for lighting 0 is selected to be higher than about 1 KHz, it may be a frequency other than 4 KHz. FIG. 5 shows the lighting frequency when the metal halide lamp 210 is rated for lighting with a rectangular wave, and the wavelength 5 of the mercury atom in front of the electrode.
It is the experimental result which calculated | required the relationship with the peak value of the light output (output voltage of a photomultiplier tube) waveform of a 77 nm emission spectrum.

As is apparent from FIG. 5, the peak value of the waveform of the light emission (output voltage of the photomultiplier tube) waveform of the emission spectrum of the mercury atom on the front surface of the electrode at the wavelength of 577 nm decreases with the increase of the lighting frequency, and the lighting frequency is The value becomes almost constant above about 1 KHz. A preferred lighting frequency range in which simple, low cost lighting circuits can be used is from about 1 KHz to about 100 KHz. Therefore, the lighting frequency is about 1KH
With a rectangular wave in the range between z and about 100 KHz, the peak value of the arc temperature near the electrode, which changes with time, can be kept low, so that the electrode temperature can be kept low, and electrons and positive ions Evaporation of the electrode due to the collision of
Since the scattering is suppressed, it should be possible to significantly improve the life characteristics of the lamp.

The second embodiment of the present invention will be described below with reference to FIG. FIG. 6 is a circuit diagram of a main part of the discharge lamp lighting device according to the second embodiment of the present invention.

In FIG. 6, reference numeral 302 denotes a lighting circuit for starting and lighting the metal halide lamp 210, which generates a high-voltage pulse for starting the DC power source 103, the full bridge inverter circuit 501 which is an inverter circuit, and the metal halide lamp 210. It is composed of a starting circuit 303 that operates.

The starting circuit 303 is the metal halide lamp 2.
10, a discharge gap 202 that starts discharging at a predetermined voltage slightly lower than the voltage output from the DC power supply 103 before the start of lighting, and a coil 402 that is a means for short-circuiting both ends of the primary winding 204a of the pulse transformer 204 and a contact point. The electromagnetic relay 401 includes a resistor 403, a resistor 201, a pulse transformer 204, and capacitors 203 and 205.

Secondary winding 204b of pulse transformer 204
Is connected in series to the metal halide lamp 210, the series circuit and the capacitor 205 are connected in parallel to the output terminal of the full-bridge inverter circuit 501, and the primary winding 204a of the pulse transformer 204 is connected in series to the discharge gap 202. At the same time, the series circuit is connected in parallel with the capacitor 203, and the capacitor 203 is charged with the output voltage of the DC power supply 103 via the resistor 201. The contact 403 of the electromagnetic relay 401 is connected in parallel to the primary winding 204a of the pulse transformer 204, while the coil 402 of the electromagnetic relay 401 receives a signal proportional to the lamp current detected by the resistor 114. . When a signal is input to the coil 402 and a current flows, the contact 403 is closed.

The full bridge inverter circuit 501 is composed of transistors 117, 118, 119 and 120 and a drive circuit 502. The drive circuit 502 causes the transistor 117 so that the frequency of the alternating current output from the full bridge inverter circuit 501 becomes 20 KHz. , 120
And transistors 118 and 119 are alternately turned on and off. Other configurations are the same as those in FIG.

The operation of this embodiment configured as described above will be described. First, before the metal halide lamp 210 starts lighting, the predetermined voltage is the step-down chopper circuit 116.
Is output from the DC power source 103 via the resistor 201 to the capacitor 203 of the starting circuit 303 at the same time as the voltage is applied to the metal halide lamp 210 by being converted into AC of a frequency of 20 KHz by the full bridge inverter circuit 501. Be charged. When the discharge gap 202 starts discharging, the voltage charged in the capacitor 203 is applied to the primary winding 204a, and the high-voltage pulse voltage boosted by the pulse transformer 204 is output from the secondary winding 204b of the pulse transformer 204. And the metal halide lamp 2 through the condenser 205.
10 is applied.

After that, when the metal halide lamp 210 starts lighting, a lamp current flows, so that the control circuit 11
The transistor 108 is controlled to be turned on / off in response to the output signal of No. 5, the output voltage of the step-down chopper circuit 116 is lowered, the discharge gap 202 of the starting circuit 303 is not discharged, and the high-voltage pulse is not applied to the metal halide lamp 210. Stop and lamp startup is complete.

After the starting circuit 303 stops operating, the transistor 108 is turned on / off by the output signal of the control circuit 115 so that the power supplied to the metal halide lamp 210 becomes a predetermined lamp power, and the step-down chopper is controlled. A predetermined DC voltage is output from the circuit 116, and the DC voltage is converted into an AC waveform (rectangular wave) having a frequency of 20 KHz by the full-bridge inverter circuit 501, and the metal halide lamp 210 receives the lamp current and keeps lighting. . Since the lamp current flows at the same time,
The signal detected by the resistor 114 is input to the coil 402 of the electromagnetic relay 401, a current flows, the contact 403 is closed, and both ends of the primary winding 204a of the pulse transformer 204 are short-circuited. This state is maintained while the metal halide lamp 210 is turned on and the lamp current is flowing.

Both ends of the primary winding 204a are electromagnetic relays 40.
The pulse transformer 20 short-circuited by the contact 403 of No. 1
The value of the inductance converted to the secondary side of 4 is the contact 40
It becomes smaller than when 3 is open, so after all,
While the metal halide lamp 210 in which both ends of the primary winding 204a of the pulse transformer 204 are short-circuited is lit, distortion of the lamp current waveform of the metal halide lamp 210 due to the inductance component of the pulse transformer 204 is suppressed. That is, even at a high lighting frequency of 20 KHz, a substantially rectangular wave lamp current can be supplied to the metal halide lamp 210.

As described above, in the discharge lamp lighting device of the present embodiment shown in FIG. 6, the distortion of the lamp current waveform due to the inductance component of the pulse transformer of the starting circuit can be suppressed, and the discharge current of 20K
Since a rectangular-wave lamp current can be supplied even at a high frequency of Hz, the electrode temperature can be suppressed to a low level, evaporation and scattering of the electrodes can be suppressed, and the lamp life can be extended.

In this embodiment, the electromagnetic relay 401 operates by detecting the lamp current of the metal halide lamp 210. However, the electromagnetic relay 401 operates by detecting other characteristics of the metal halide lamp 210, for example, the lamp voltage. It doesn't matter.

In this embodiment, the pulse transformer 204
The electromagnetic relay 401 has been described as an example of means for short-circuiting both ends of the primary winding 204a, but the means for short-circuiting both ends of the primary winding 204a of the pulse transformer 204 may be another means, for example, a transistor. Absent.

In the first and second embodiments, the metal halide lamp in which Ar gas is filled as the starting rare gas has been described as an example, but K which is heavier than Ar is used.
A metal halide lamp filled with r or Xe gas may be used. In this case, the electrode material in which Kr or Xe is scattered from the electrode acts as an obstacle to move to the tube wall of the arc tube, and another effect of preventing blackening of the arc tube is obtained.

In the first and second embodiments, the metal halide lamp has been described as an example, but it is obvious that the same effect can be obtained with other high pressure discharge lamps. Although the present invention has been described with reference to the preferred embodiment, it goes without saying that such description is not a limitation and various modifications can be made.

[0042]

As described above, according to the present invention, in the high pressure discharge lamp, about 1 KHz and about 100 KHz from the lighting circuit.
By supplying a lamp current with a substantially rectangular wave at a frequency selected in the range between, the peak value of the arc temperature near the electrode that changes with time can be suppressed to a low level, and sputtering by cathode positive ions can be performed. Is suppressed. Therefore, the evaporation and scattering of the electrodes are suppressed, the blackening of the arc tube of the high pressure discharge lamp is suppressed, and a long-life and economical discharge lamp lighting device can be provided.

Further, by enclosing Kr gas or Xe gas as a starting rare gas in the high pressure discharge lamp, the electrode material scattered from the electrode acts as an obstacle to move to the tube wall of the arc tube, and the arc tube It is possible to prevent blackening.

Further, at least a starting circuit for starting the metal halide lamp is provided between the output end of the inverter circuit for converting the DC output of the DC power supply into the AC and the metal halide lamp, and at least the secondary winding has a high pressure discharge lamp. The lamp current waveform caused by the inductance component of the pulse transformer is configured by connecting both ends of the pulse transformer connected in series with the pulse transformer and the primary winding of the pulse transformer while the high-voltage discharge lamp is lit. Can suppress the distortion of about 1KHz and about 100KH
It is possible to provide a highly practical discharge lamp lighting device capable of supplying a substantially rectangular wave lamp current at a lighting frequency in the range between z.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a main part of a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a lamp current waveform diagram of the discharge lamp lighting device according to the first embodiment of the present invention.

3A and 3B are optical output waveform diagrams of the discharge lamp lighting device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between a lighting time and a luminous flux maintenance factor of the discharge lamp lighting device of the first embodiment.

FIG. 5 is a diagram showing a relationship between the lighting frequency and a peak value of a mercury emission line spectrum.

FIG. 6 is a circuit diagram showing a main part of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 7 is a circuit diagram showing a conventional discharge lamp lighting device.

FIG. 8 is an output voltage waveform diagram of a conventional step-down chopper circuit.

FIG. 9 is an output voltage waveform diagram of a conventional full bridge inverter circuit.

[Explanation of symbols]

 14 Full Bridge Inverter Circuit 15 Starting Circuit 104 Full Bridge Inverter Circuit 116 Step-Down Chopper Circuit 202 Discharge Gap 204 Pulse Transformer 204a Pulse Transformer 204 Primary Winding 204b Pulse Transformer 204 Secondary Winding 210 Metal Halide Lamp 220 Drive Circuit 301 Lighting Circuit 302 Lighting circuit 303 Starting circuit 401 Electromagnetic relay 402 Coil 403 Contact 501 Full bridge inverter circuit 502 Drive circuit

Claims (6)

[Claims] 1. A high-pressure discharge lamp and a lighting circuit for supplying the high-pressure discharge lamp with a substantially rectangular wave lamp current at a frequency selected in a range between about 1 KHz and about 100 KHz. Characteristic discharge lamp lighting device. 2. A high-pressure discharge lamp uses K as a starting rare gas.
The discharge lamp lighting device according to claim 1, wherein r gas or Xe gas is enclosed. 3. The lighting circuit includes at least a DC power supply, an inverter circuit connected to the output end of the DC power supply for converting the DC output of the DC power supply into AC, an output end of the inverter circuit and a metal halide lamp. The discharge lamp lighting device according to claim 1 or 2, further comprising: a start circuit for starting the metal halide lamp. 4. A starting circuit comprises a pulse transformer having a secondary winding connected in series with a high pressure discharge lamp, and both ends of a primary winding of the pulse transformer, while the high pressure discharge lamp is lit. The discharge lamp lighting device according to claim 3, further comprising means for short-circuiting. 5. The discharge lamp lighting device according to claim 4, wherein the means for short-circuiting both ends of the primary winding of the pulse transformer comprises a switching element. 6. The high pressure discharge lamp is a metal halide lamp, and at least the metal halide lamp comprises:
6. The discharge lamp lighting device according to claim 1, wherein dysprosium iodide, neodymium iodide and cesium iodide are enclosed.