JPH0567496A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To rise light output speedily regardless of a lighting or lights-out condition, and also prevent the excessive light output in a discharge lamp lighting device to control lighting of a discharge lamp. CONSTITUTION:When a direct current electric power supply 1 is turned on, an inverter circuit 2 oscillates. When output of the direct current electric power supply 1 reaches prescribe voltage, a lighting control circuit 8 receives output of a direct current voltage detecting circuit 7, and operates a startup circuit 4. Thereby, a discharge lamp 5 is started, and when an electric current is flowed to the lamp, voltage on both ends of the discharge lamp 5 is lowered, and voltage of the direct current electric power supply 1 is also lowered. From this voltage drop, a direct current voltage detecting circuit 6 detects the fact that the discharge lamp 5 is started, and stops operation of the startup circuit 4. After the discharge lamp 5 is started, the lighting control circuit 8 controls the output of the direct current electric power supply 1 according to a lighting time and a lights-out time, and the output immediately after the lamp is started is increased as the lights-out time becomes long, and after the lamp is once started, the output is decreased with the lapse of time, and rated lighting can be carried out soon.

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 controlling the lighting of a discharge lamp such as a metal halide lamp.

[0002]

2. Description of the Related Art When a high pressure discharge lamp such as a metal halide lamp is started from a cold state, the light output does not easily increase with the same electric power unless the vapor pressure of the light emitting metal rises with time. For this reason, in order to quickly raise the light output of such a lamp, it is already known to use a method in which a large lamp current is passed immediately after the start, and the rated lighting is performed by reducing it to a predetermined lamp current over time. -10697 publication.

[0003]

However, in the apparatus for carrying out the above method, the case of a cold lamp is good,
If you turn on the lamp for a long time, then turn it off, and start again in a short time,
If the lamp is warm, such as when it is turned on for a long time and then turned off, then restarted after a while, when it is turned on for a short time and then restarted in a short time There is a problem that the light output does not occur, but rather the light output is excessive and the temperature rise of the lamp is large, so that the lamp has a short life.

[0004]

In order to solve the above-mentioned problems, a discharge lamp lighting device according to the present invention comprises a lamp current supply means, a discharge lamp connected to the lamp current supply means, a turn-off time and a lighting time. The lighting control means controls the output of the lamp current supply means in accordance with the above, and increases the output immediately after the start as the extinguishing time is longer, and decreases the output with the lighting time after the start to perform the rated lighting control. Is.

Further, the lamp current supply means includes a DC power supply and an inverter means driven by the DC power supply to oscillate, and the lighting control means controls the output of the DC power supply to output the lamp current supply means. Is controlled.

Further, the lighting control means sets the output current level or the output power level of the lamp current supply means immediately after the start of the discharge lamp immediately after the power is turned on and immediately after the start of the discharge lamp. It is provided with means for controlling the level or output power level so as to reduce the rated lighting.

[0007]

With the above structure, the output of the lamp current supply means is controlled according to the extinction time and the extinction time, and the longer the extinction time is, the larger the output immediately after the start is made. Control so that
It is possible to quickly start the light output regardless of whether it is turned off or turned on and prevent the light output from being excessive.

Further, since the lamp current supply means is provided with the direct current power source and the inverter means driven by the direct current power source to oscillate, the discharge lamp can be lit with a rectangular wave alternating current of a low frequency, and the discharge lamp can be used. Detrimental electrophoretic and acoustic resonance phenomena can be reduced or substantially eliminated. Further, since the lighting control means controls the output of the lamp current supply means by controlling the output of the DC power supply, detection and control can be facilitated.

Further, the lighting control means sets the output current level or the output power level of the lamp current supply means immediately after the start of the discharge lamp after the power is turned on and immediately after the start of the discharge lamp. Since the means for controlling the level or the output power level to be reduced and the rated lighting is provided, the control can be reliably performed without the influence of noise and the like.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the basic configuration of a discharge lamp lighting device according to an embodiment of the present invention. In FIG. 1, 1 is a DC power supply, and an inverter circuit 2 is driven by the DC power supply 1 to invert a DC voltage at a predetermined frequency,
Output square wave voltage. The DC power supply 1, the inverter 2, and the inverter form the lamp current supply means 3. The inverter circuit 2 has a starting circuit 4 including an inductance component as a load circuit, and a discharge lamp 5 such as a metal halide lamp. Further, the output of the DC power supply 1 detects the start of the discharge lamp 5, and the DC voltage detection circuit 6 for detecting the DC voltage and the DC current detection circuit 7 for detecting the DC current in order to control the subsequent start and rated lighting. Is provided. The output signals of the DC voltage detection circuit 6 and the DC current detection circuit 7 are input to the lighting control circuit 8, and the lighting control circuit 8 varies the oscillation frequency of the DC power supply 1 or its duty ratio based on these signals, and the discharge lamp 5 Control the lighting operation of.

Next, the operation of the above configuration will be described. When the DC power supply 1 is turned on, the inverter circuit 2 first oscillates at a high frequency of about 5 kHz, and the DC voltage detection circuit 7
Detects the output voltage of the DC power supply 1, and when this voltage reaches a predetermined voltage for starting, the lighting control circuit 8 receives the output of the DC voltage detection circuit 7 and operates the starting circuit 3 to cause the discharge lamp 5 to operate. Apply the starting voltage. The discharge lamp 5 is started by this starting voltage, and when a current flows through the discharge lamp 5, the voltage across the discharge lamp 5 decreases and the output voltage of the DC power supply 1 also decreases. By detecting this voltage drop in the DC voltage detection circuit 6, it is detected that the discharge lamp 5 has started, and the operation of the start circuit 4 is stopped. After the discharge lamp 5 is started, the lighting control circuit controls the output of the DC power supply 1 according to the extinction time and the extinction time, and the longer the extinction time is, the larger the output immediately after the start is. Eventually, the rated light is turned on. Also, when the output approaches the rated value, the oscillation frequency of the inverter is lowered to a low frequency of about 400 Hz, and the inverter is lit stably without the problem of acoustic resonance.

FIG. 2 is a circuit diagram showing a main part of the DC power supply 1. In FIG. 2, the DC power supply 1 is composed of a series circuit of a flyback transformer 10 and a transistor 11 connected to a battery 9, and a series circuit of a diode 12 and a capacitor 13 connected to a secondary winding of the flyback transformer 10. It has a configuration of a flyback type DC / DC converter. Both ends of the capacitor 13 are outputs of the DC power supply 1, 6 is a DC voltage detection circuit, 7 is a DC current detection circuit, and 14 is a control circuit for controlling the output of the DC power supply 1. The control circuit 14 includes a switching regulator control IC 15, a buffer circuit 16, a set voltage circuit 17,
18, the outputs of the DC voltage detection circuit 6 and the DC current detection circuit 7 are connected to the positive input of the error amplifier EA1 and the negative input of the error amplifier EA2 of the IC 15, and the set voltage circuit 1
The outputs of 7 and 18 are connected to the negative input of the error amplifier EA1 and the negative input of the error amplifier EA2, and the oscillation output E of the IC 15 is output.
1 and E2 pass through the buffer circuit 16 and the transistor 11
Has been entered into the gate. As a result, when the battery 9 is turned on, a current flows through the flyback transformer 10 due to the switching of the transistor 11, a voltage is generated in this secondary winding, rectified by the diode 12, smoothed by the capacitor 13, and a DC voltage is generated. Output. At this time, the output voltage and the output current are detected by the DC voltage detection circuit 6 and the DC current detection circuit, and compared with the outputs of the set voltage circuits 17 and 18 by the error amplifiers EA1 and EA2 so that the voltage and the current do not exceed the set level. Control is performed by changing the duty ratio of the oscillation outputs E1 and E2. As a result, the output of the DC power supply 1 stabilizes at the lower value of the voltage and current setting values.

FIG. 3 is a circuit diagram showing a main part of the inverter circuit 2. In FIG. 3, the inverter circuit 2 has a structure of a bridge inverter composed of four transistors Q1, Q2, Q3, Q4 for supplying a rectangular wave alternating current to the discharge lamp 5 via the starting circuit 4. Reference numeral 19 denotes an oscillator, which oscillates at a predetermined frequency in response to a signal from the lighting control circuit 8 and outputs a two-phase clock signal which is alternately turned on to the drive circuit 20. The drive circuit 20 is a circuit for receiving the output of the oscillation circuit 19 and driving the bridge inverter,
The output is connected to the gates of transistors Q1, Q2, Q3, Q4,
A pair of diagonally opposed switching transistors Q ₁ , Q ₄
The switching transistors Q ₂ and Q ₃ are configured such that when one of Q ₁ and Q ₄ is turned on at the same time, the other Q ₂ and Q ₃ are turned off at the same time. As a result, when there is a control input a from the lighting control circuit 8, the oscillation frequency of the inverter is 5 kHz.
When the control input is absent, the oscillation frequency of the inverter can be set to about 400 Hz. Furthermore, a time constant can be added to the frequency setting circuit of the oscillator 19 to gradually change it.

FIG. 4 is a circuit diagram showing a main part of the starting circuit 2. In FIG. 4, the starting circuit is the output VDC of the DC power supply 1.
A pulse circuit including a series circuit of a pulse transformer 21 and a transistor 22 connected to the oscillator, an oscillator 23 which starts oscillation upon receiving a control signal b from the lighting control circuit 8 and a buffer circuit 24 which switches the transistor 22 by the output of the oscillator 23. It has a configuration of a generation circuit. The discharge lamp 5 is connected to the secondary winding of the pulse transformer 21 and receives the control signal b from the lighting control circuit 8 to start the discharge lamp 5 by a high-voltage pulse generated in the secondary winding.

FIG. 5 is a circuit diagram showing a main part of the lighting control circuit 8. In FIG. 5, the lighting control circuit 8 receives the output of the DC voltage detection circuit 6a that detects the output voltage VDC of the DC power supply 1 and determines whether the discharge lamp 5 is lit.
5, the output VDC of the DC power supply 1, the output of the DC current detection circuit 7 and the output of the starting power signal circuit 29, and the DC power supply 1
The power control circuit 26 that inputs a signal to the error amplifier EA2 of the IC 15 to control the output power of the DC power supply 1 and the turn-off time circuit 27 that receives the output of the lighting determination circuit 25 and outputs a larger signal as the turn-off time increases. And a starting power setting trigger circuit 28 that triggers the output of the extinguishing time circuit 27 when the discharge lamp 5 lights up in response to the output of the lighting determination circuit 25, and the discharge lamp 5 receives the output of the extinction time circuit 27. After the power level is set immediately after the start of, the start power signal circuit 29 outputs a signal for reducing the start power level to the power control circuit 26 with the passage of time, and the output of the start power signal circuit 29 determines the start period. Then, the oscillator 19 of the inverter 2 is oscillated at a high frequency, and the control signal a is output so that the oscillator 19 oscillates at a low frequency when the starting period ends Consisting of the road 30.

The lighting discrimination circuit 25 compares the output voltage of the DC voltage detection circuit 6a for detecting the output voltage VDC of the DC power supply 1 with the output voltage of the setting circuit 31 by the comparator COMP1 so that the output voltage of the DC power supply 1 is lower than a predetermined voltage. When it is high, LOW is output, and when it is lower than a predetermined voltage, a HIGH control signal b is output. This control signal b is generated by the oscillator 2 of the starting circuit 4.
3 is input to generate a starting pulse when LOW.
Further, when the control signal b is LOW, the output of the DC voltage detection circuit 6b input to the power control circuit 26 is short-circuited by the transistor Q6 so that the output of the operational amplifier OP1 is set to 0V so that a large current can flow even if the DC voltage becomes high. There is. As a result, I of the DC power supply 1 is maintained during the period in which the start pulse is generated.
The error amplifier EA1 in C15 can be operated to bring the DC voltage to the constant voltage required for starting.

When the discharge lamp 5 is started, a large DC current flows, the DC voltage drops, and the control signal b output from the lighting determination circuit 25 becomes HIGH. Therefore, the starting circuit 4
Operation stops and the start pulse stops. Further, the transistor Q6 is turned off, and the output of the DC voltage detection circuit 6b in the power control circuit 26 becomes valid. In addition, the control signal b is HI
When it becomes GH, in the power signal setting trigger circuit 28, the transistor Q7 is turned on for a time determined by the capacitor C28 and the resistor R28, and the trigger signal that the output of the power signal setting trigger circuit 28 becomes 0V is output. Although the power signal setting trigger circuit 28 receives the control signal b which is the output of the lighting determination circuit 25 and outputs the trigger signal, the power signal setting trigger circuit 28 detects the turning on of the DC power supply 1 and outputs the trigger signal. Alternatively, it may be from the time when the DC power supply 1 is turned on to the time when the lamp is turned on.

The extinguishing time circuit 27 receives the control signal b, integrates it with the resistor R27 and the capacitor C27, outputs this integrated output via the buffer amplifier OP2, and the operational amplifier OP3 outputs the bias circuit 32 and the power signal setting trigger circuit. The output of 28 is added, inverted and amplified, and output. Since the output of the power signal setting trigger circuit 28 is normally HIGH, the output of the operational amplifier OP3 is negative and the diode 33
However, when the output of the power signal setting trigger circuit 28 becomes OV, the operation of the bias circuit 32 that outputs a negative bias voltage and the operational amplifier OP3 causes the output of the operational amplifier OP2. Accordingly, as the output voltage of the operational amplifier OP2 is lower, the operational amplifier OP3 outputs a higher voltage. That is, the turn-off time becomes longer and R2
7, the lower the voltage of the integration circuit of C27, the higher the output voltage of the extinction time circuit 27 can be.

In the starting power signal circuit 29, the turn-off time circuit 2
The capacitor 29 is charged by receiving the output of 7 and outputs this voltage to the power control circuit 26 via the buffer amplifier OP4. Immediately after the discharge lamp 5 is started, the voltage of the capacitor 29 is charged by the output voltage from the extinguishing time circuit 27 due to the signal of the power signal setting trigger circuit 28, but thereafter, it is discharged by the resistor R29 with the passage of time and gradually. descend. Therefore, the output of the starting power signal circuit 29 gradually decreases.

The output of the starting power signal circuit 29 is input to the power control circuit 26, and the output of the DC current detection circuit 7, the output of the set voltage circuit 18, and the output voltage VDC of the DC power supply 1 are detected by the DC voltage detection circuit 6b. The output obtained by inverting and amplifying the output of the
Is input to the negative input terminal of the error amplifier EA2. The error amplifier EA2 of the control circuit 14 shown in FIG. 2 shows an example of a circuit in which the output of the set voltage circuit 18 and the output of the DC current detection circuit 7 are input, and the current can be controlled by this.
In the power control circuit 26, a circuit is added to enable power control. By doing this, these 4
Transistor 11 of the DC power supply 1 so that the current input to the negative input terminal of the error amplifier EA2 becomes zero by the two signals.
The power can be controlled by changing the ON duty ratio of. In addition to the output of the DC current detection circuit 7 and the output of the set voltage circuit 18 shown in FIG.
By inputting the output that is inverted and amplified by, the control is performed so that the result of adding the negative signal corresponding to the DC current and the negative signal corresponding to the DC voltage matches the output voltage of the constant positive set voltage circuit 18. Therefore, the output of the DC power supply 1 can be approximately constant power within a certain current / voltage range, and the power input to the discharge lamp 5 via the inverter circuit 2 can also be constant. Further, by inputting the output of the starting power signal circuit 29, compared to the rated power determined by the set voltage circuit 18, the light-off time circuit 27 outputs the light-off time according to the light-off / light-up time at the time of start-up so that the light-off time up to that time is long. The shorter is, the larger the starting power can be made to flow to the discharge lamp 5, and the large power is input to the discharge lamp 5 according to the turn-off / lighting time to promptly start the light output,
It is possible to prevent the light output from being excessively output by controlling the lamp power to gradually approach the rated power and to be rated lighting with the passage of time after the start of the discharge lamp 5.

Here, the signal according to the DC current and the signal according to the DC voltage are added, and the result is controlled to be a predetermined value, so that the lighting can be approximately performed with the predetermined power. It goes without saying that more accurate power control can be achieved by multiplying the signal according to the DC current and the signal according to the DC voltage and controlling the result to a predetermined value so that the lamp is lit with a predetermined power. Nor.

The starting period determining circuit 30 compares the output of the starting power signal circuit 29 with the voltage of the set voltage circuit 34 by the comparator COMP2 and determines that the starting period is reached when the output of the starting power signal circuit 29 is high. Then, the control signal a is output, the oscillator 19 of the inverter 2 is oscillated at a high frequency, and when the output of the starting power signal circuit 29 is low, it is considered that the starting period has ended and the oscillator is oscillated at a low frequency. Since the control is performed in this manner, by increasing the frequency of the inverter during the starting period, the inductance of the starting circuit 4 can have a voltage, and the DC voltage can be increased even with the same output power, and the lamp voltage during the starting period can be increased. Even if it is low, the re-ignition voltage necessary for AC inversion can be secured, and the lighting can be reliably maintained during this period. Further, after completion of the starting period, the discharge lamp 5 can be lit with a rectangular wave alternating current of a low frequency, and electrophoretic and acoustic resonance phenomena harmful to the discharge lamp 5 can be reduced or substantially eliminated. However, it goes without saying that the frequency need not necessarily be changed during the starting period as long as a sufficient re-ignition voltage can be obtained at a low frequency.

FIG. 6 is a circuit diagram showing the essential parts of another embodiment of the starting power signal circuit and the extinguishing time circuit. 6 is different from the circuit of FIG. 5 in that the time constant circuit corresponding to the extinguishing time / lighting time and the time constant circuit for lowering the control signal so as to gradually decrease the starting power after starting the discharge lamp are commonly used. That is, the signal setting trigger circuit is omitted.

The starting power signal circuit 35 is a lighting discrimination circuit 25.
When the discharge lamp 5 is lit by receiving the output of, that is, when the output of the starting power signal circuit 35 is HIGH, the capacitor C35 is charged through the resistor R35a and the diode 36, and the discharge lamp 5 is turned off. That is, when the output of the starting power signal circuit 35 is LOW, the resistance R35
b, the capacitor C35 is discharged through the diode 37. Further, similarly to the buffer amplifier OP2, the bias circuit 32 and the operational amplifier OP4 in FIG. 5, the buffer amplifier OP5, the bias circuit 38 and the operational amplifier OP6 are connected to output the integrated output of the capacitor C35 via the buffer amplifier OP5, and the operational amplifier OP6. Thus, the output of the bias circuit 38 is added, inverted and amplified, and output. By the operation of the bias circuit 38 that outputs a negative bias voltage and the operational amplifier OP6,
According to the output of the operational amplifier OP5, the lower the output voltage of the operational amplifier OP5, the higher the operational amplifier OP6 outputs. That is, the longer the extinguishing time is or the shorter the lighting time is, the lower the voltage of C35 becomes, and the starting power signal circuit 3
It is possible to increase the output voltage of the discharge lamp 5 and increase the starting power immediately after the discharge lamp 5 is started. Further, after the discharge lamp 5 is started, the output of the lighting determination circuit 31 becomes HIGH, and the voltage of the capacitor C35 rises with the lapse of time. Therefore, the output of the starting power signal circuit 35 drops and eventually becomes 0V. For this reason, the starting power is reduced and the discharge lamp 5 comes on at the rated power. The diodes 39 and 40 are used in place of the diode 33 of FIG. 5, whereby the operational amplifier OP6 can perform the inverting amplification of the absolute value without the influence of the forward voltage of the diode. As described above, the starting power signal circuit 35 of FIG. 6 enables power control according to the turn-off / light-on time with a simple circuit. In this embodiment, the time constant according to the turn-off time and the time constant according to the turn-on time are independently changed by the resistors R35a and R35b, but if the same time constant is acceptable, the diode 36,
37 is unnecessary and the resistance may be common. Further, the discharging resistor R35b may be provided in parallel with the capacitor C35.

Needless to say, it is necessary to select the time constants of the light-off time circuit and the starting power signal circuit so that the optical output rises promptly and the optical output after starting does not become too large.

In the above embodiments, the flyback type DC / DC converter is used as the DC power source, but a forward type DC / DC converter and a push-pull type DC converter are used.
A DC power source such as a / DC converter may be used, and the inverter circuit may be an inverter of another type such as a half bridge type or a push pull type.

Further, in the above embodiment, the DC power source 1
However, it goes without saying that the inverter circuit 2 may be controlled, and the output of the lamp current supply means may be controlled regardless of these configurations.

Further, in the above embodiments, an example of a low frequency rectangular wave lighting device is shown, but the present invention is not limited to this, and if the discharge lamp does not cause harmful phenomena such as electric permanence and acoustic resonance. Other lighting devices such as a high frequency lighting device, a direct current lighting device, etc. may be used.

As described above, the output of the lamp current supply means is controlled according to the turn-off time and the turn-on time, the output immediately after the start is increased as the turn-off time is longer, and the output is decreased with the turn-on time after the start, and the rated turn-on is performed. Therefore, it is possible to promptly start the light output regardless of whether it is turned off or turned on and prevent the light output from being excessive.

Further, since the lamp current supply means is provided with the direct current power source and the inverter means driven by the direct current power source to oscillate, the discharge lamp can be lit with a rectangular wave alternating current of a low frequency, and the discharge lamp can be used. Detrimental electrophoretic and acoustic resonance phenomena can be reduced or substantially eliminated.

Further, since the lighting control means controls the output of the lamp current supply means by controlling the output of the DC power supply, detection and control can be facilitated.

Further, the lighting control means sets the output current level or the output power level of the lamp current supply means immediately after the start of the discharge lamp after the power is turned on and immediately after the start of the discharge lamp. Alternatively, since the means for controlling the output power level to be reduced and the rated lighting is provided, the control can be surely performed without the influence of noise and the like.

The starting circuit for applying a high voltage to the discharge lamp to start the discharge lamp by being driven by the lamp current supply means, and the lighting control means, after the power is turned on, until the discharge lamp is lit. Since the means for controlling the output voltage level of the lamp current supply means to be constant is provided, the discharge lamp can be reliably started without being affected by the current at the time of lighting the discharge lamp and the power control means.

Further, the lighting control means is provided with a discriminating circuit for discriminating that the discharge lamp is in the starting period, and means for controlling by the output of the discriminating circuit to increase the frequency of the inverter during the starting period. The start-up period can be reliably determined, and the lighting can be reliably maintained during this period. After the start-up period, the lamp can be lit with a low frequency rectangular wave alternating current,
Electrophoretic and acoustic resonance phenomena harmful to discharge lamps can be reduced or substantially eliminated.

[0036]

As described above, according to the present invention, the output of the lamp current supply means is controlled according to the extinguishing time and the lighting time, the output immediately after starting is increased as the extinguishing time becomes longer, and the lighting time after starting is increased. At the same time, the output is controlled to be reduced and the rated lighting is performed. Therefore, it is possible to promptly start the light output regardless of the turned-off / lighting state and prevent the light output from being excessive.

Further, since the lamp current supply means is provided with the direct current power source and the inverter means driven by the direct current power source to oscillate, the discharge lamp can be lit by the rectangular wave alternating current of a low frequency, and the discharge lamp can be used. Detrimental electrophoretic and acoustic resonance phenomena can be reduced or substantially eliminated. Further, since the lighting control means controls the output of the lamp current supply means by controlling the output of the DC power supply, detection and control can be facilitated.

Further, the lighting control means sets the output current level or the output power level of the lamp current supply means immediately after the start of the discharge lamp after the power is turned on and immediately after the start of the discharge lamp. Alternatively, since the means for controlling the output power level to be reduced and the rated lighting is provided, the control can be surely performed without the influence of noise and the like.

[Brief description of drawings]

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

FIG. 2 is a circuit configuration diagram showing a main part of a DC power supply according to an embodiment of the present invention.

FIG. 3 is a circuit configuration diagram showing a main part of an inverter circuit according to another embodiment of the present invention.

FIG. 4 is a circuit configuration diagram showing a main part of a starting circuit according to another embodiment of the present invention.

FIG. 5 is a circuit configuration diagram showing a main part of a lighting control circuit according to another embodiment of the present invention.

FIG. 6 is a circuit configuration diagram of a main part of a power control signal circuit according to an embodiment of the present invention.

[Explanation of symbols]

 1 DC power supply 2 Inverter circuit 3 Lamp current supply means 4 Starting circuit 5 Discharge lamp 6 DC voltage detection circuit 7 DC current detection circuit 8 Lighting control circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeru Horii 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Koji Miyazaki, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Atsuo Waki, 1006 Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A lamp current supply means, a discharge lamp connected to the lamp current supply means, and an output of the lamp current supply means is controlled according to a turn-off time and a lighting time. The discharge lamp lighting device is provided with a lighting control means that controls the lighting so that the output is increased and the output is decreased with the lapse of time after starting. 2. The lamp current supply means comprises a DC power supply and an inverter means driven and oscillated by the DC power supply, and the lighting control means controls the output of the DC power supply to control the output of the lamp current supply means. The discharge lamp lighting device according to claim 1, configured as described above. 3. The lighting control means sets an output current level or an output power level of the lamp current supply means immediately after the start of the discharge lamp after the power is turned on and immediately after the start of the discharge lamp. The discharge lamp lighting device according to claim 1, further comprising means for controlling the current level or the output power level so as to reduce the current level or the rated power level.