JPH05144577A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To raise up optical output speedily regardless of a lamp voltage or on/off conditions of lighting, and prevent excessive optical output for a discharge lamp lighting device. CONSTITUTION:When a DC power supply 1 is applied, an inverter circuit 2 oscillates. When an output of the DC power supply 1 reaches a specified voltage, a lighting control circuit 8 receives output of a DC voltage detection circuit 7 and actuates a start circuit 3 for starting a discharge lamp 5. After the discharge lamp 5 is started, output of the DC power supply 1 is controlled by the lighting control circuit 8 in accordance with a lamp voltage when the lamp voltage is lower than a specified voltage, and in accordance with a lighting-off time and a lighting time when the lamp voltage is higher than the specified voltage to set the output larger as the lighting-off time is longer immediately after starting, and set the output gradually smaller as time elapses after starting till lighting at a rated value is achieved.

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 promptly raise the light output of such a lamp, it is already known to use a method of inputting a large lamp power immediately after starting and reducing it to a predetermined lamp power with the passage of time to perform rated lighting. It is known from the 2-10697 publication.

[0003]

However, in the apparatus for carrying out the above method, since the lamp state is not detected, the light output may be excessive or insufficient depending on the lamp state. In the case of a cold lamp, it is good, but if it is turned on for a long time and then turned off and restarted in a short time, if it is turned on for a long time and then turned off and restarted after a while, after it is turned on for a short time If the lamp is warm, such as when it is turned off and restarted in a short time, the specified light output will not be obtained immediately after restarting, but rather the light output will be too high or the temperature of the lamp will rise too much. There is a problem that it has a short life.

The present invention solves the above problems, and provides a discharge lamp lighting device in which the light output is quickly raised regardless of the lamp voltage, the state of turning off the lamp, and the light output is not excessive. It is intended.

[0005]

In order to solve the above problems, a discharge lamp lighting device of the present invention detects a lamp current supply means, a discharge lamp connected to the lamp current supply means, and a lamp voltage. Lamp voltage detecting means, lamp current detecting means for detecting lamp current, a power control circuit for controlling lamp power by receiving outputs of the lamp voltage detecting means and lamp current detecting means, and the lamp voltage detecting means in the lamp starting region. When the lamp voltage is low, the lamp current supply means is controlled to input a large lamp power to the discharge lamp, and when the lamp voltage is high, the lamp current supply means is controlled to generate a small lamp power. Is supplied to the discharge lamp, and after the lamp starting region, there is provided lighting control means for controlling the discharge lamp so as to perform rated lighting.

Further, the lamp current supply means includes a direct current power source and an inverter means driven by the direct current power source to oscillate. In addition, the lighting control means controls the output of the lamp current supply means by controlling the output of the DC power supply, and further detects the output voltage of the DC power supply by the lamp voltage detection means to determine the lamp current. The detection means detects the output current of the DC power supply and controls the output of the DC power supply to control the output of the lamp current supply means.

Further, the lighting control means of the present invention comprises a lamp power calculation means for decreasing the output signal with an increase in the lamp voltage below a predetermined lamp voltage and a lamp power calculation means for making the output signal 0 above a predetermined lamp voltage, and a bias means. The output of the lamp current supply means is controlled by the addition output of the lamp power calculation means and the bias means.

Further, the lighting control means of the present invention has a time constant switching means which is connected to the lamp power calculating means and operates at a predetermined lamp voltage, and when the lamp voltage becomes equal to or higher than a predetermined voltage, the lamp power calculating means. Is configured to switch the time constant in order to increase the time constant of the decrease with respect to the lamp power.

Further, the lighting control means of the present invention is provided for
Immediately after restarting, there is provided a starting initial power setting means for setting the initial lamp power so that a predetermined lamp power larger than the lamp power at least during stable lighting is supplied, and the starting power corresponding to the set initial lamp power and lamp voltage is set. The larger one of the lamp powers is input to the discharge lamp, and the discharge lamp is controlled to be rated after the lamp starting region.

Further, the lighting control means of the present invention is, as the initial power setting means for starting, a light-off time detecting means for detecting a light-off time of the lamp, and at least immediately after starting / restarting according to the output of the light-off time detecting means. Equipped with a starting power signal setting trigger means that can set the initial lamp power so that a greater amount of lamp power will flow when the lighting time is longer than the lighting power, and the starting power according to the lighting time and the starting power according to the lamp voltage. The larger one of the two lamp powers is input to the discharge lamp, and the discharge lamp is controlled to be rated after the lamp starting region.

[0011]

With the above construction, when the lamp voltage detection means detects a low lamp voltage in the starting region of the discharge lamp, the output of the lamp current supply means is controlled to flow a large lamp power, and a high lamp voltage is detected. Controls the output of the lamp current supply means to flow a small lamp power, so that the lamp power can be reliably controlled and the lamp can be lit at the rated lamp power during stable lighting.

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 the rectangular wave alternating current of low frequency, which is harmful to the discharge lamp. Electrophoresis and acoustic resonance phenomena can be reduced or substantially eliminated.

Since the lighting control means controls the output of the lamp current supply means by controlling the output of the direct current power source, the output voltage of the direct current power source is detected instead of the lamp voltage, and the lamp is supplied. Since the output current of the DC power supply is detected instead of the current and the output of the DC power supply is controlled to control the output of the lamp current supply means, the detection and control can be facilitated.

Further, when the voltage is less than the predetermined lamp voltage, the output signal decreases with an increase in the lamp voltage, and when the voltage is higher than the predetermined lamp voltage, there is provided a lamp power calculating means and a biasing means, and the bias power calculating means is provided. Since the output of the lamp current supply means is controlled by the addition output of the bias means and a predetermined lamp voltage in the starting region of the lamp, a large lamp power at the time of starting is input to quickly increase the luminous flux of the discharge lamp. , It lights at the rated power when the lamp voltage is higher than a predetermined level.

Further, when the lamp voltage becomes equal to or higher than a predetermined voltage, the time constant switching means switches the time constant so as to increase the time constant of the decrease of the lamp power in the lamp power calculation means, and the lamp power is changed to a large time constant. Since the rated lighting is gradually changed, the light output after the start can be changed to the stable lighting without a large change after the rated output.

Further, immediately after starting and restarting, the initial lamp power is set so that a predetermined lamp power at least larger than the lamp power at the time of stable lighting is supplied, and particularly at restart, the lamp voltage is set to the lamp voltage at stable lighting. Even in a similar case, by inputting a large lamp power, even if the enclosed metal adheres to the tube wall of the lamp when the lamp is turned off, a light output close to that during stable lighting can be obtained immediately after restart.

Further, the initial lamp power is set so that a predetermined lamp power larger than the lamp power at least during stable lighting is flowed immediately after starting / restarting according to the output of the light-off time detecting means, and when the light-off time is short. By setting the initial lamp power to be larger when the lamp is longer than the lamp, the luminous efficiency does not decrease because the vapor pressure of the enclosed metal does not decrease when the extinguishing time is short, and the enclosed metal In such a case, a large amount of lamp power is not input at the time of restart, and conversely the vapor pressure decreases and the enclosed metal adheres to the pipe wall as the light-off time increases. In this case, a large lamp power can be input at the time of restart since the influence becomes large, and a light output close to that at stable lighting can be obtained immediately after restart.

[0018]

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, reference numeral 1 denotes a DC power supply, and the inverter circuit 2 is driven by the DC power supply 1 to invert the DC voltage at a predetermined frequency and output a rectangular wave voltage. The DC power supply 1 and the inverter 2 form a 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. Furthermore, the output of the DC power supply 1
A direct current voltage detection circuit 6 for detecting a direct current voltage and a direct current detection circuit 7 for detecting a direct current are connected to detect the start-up of the discharge lamp 5 and control the subsequent start-up and rated lighting. 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 changes 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 oscillates at a low frequency of about 400 Hz at which the problem of acoustic resonance does not occur, and the DC voltage detection circuit 7 detects the output voltage of the DC power supply 1 and this voltage is When the voltage reaches a predetermined voltage for starting, the lighting control circuit 8 receives the output of the DC voltage detecting circuit 7 and operates the starting circuit 4 to apply the starting voltage to the discharge lamp 5.
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 8 controls the output of the DC power supply 1 in accordance with the extinction time and the extinction time, and the longer the extinction time is, the larger the output immediately after the start is. The size will be reduced and the rating will be lit soon.

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 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. And a flyback type DC / DC converter. Both ends of the capacitor 13 are the output of the DC power supply 1, and 6 and 7 correspond to the DC voltage detection circuit and the DC current detection circuit of FIG. Reference numeral 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, and a set voltage circuit.
17 and 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 IC15, and the set voltage circuit 17,
The output of 18 is the negative input of the error amplifier EA1, the error amplifier EA
The oscillation outputs E1 and E2 of the IC 15 are input to the gate of the transistor 11 via the buffer circuit 16. 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, is rectified by the diode 12, smoothed by the capacitor 13, and is a DC voltage. Is output. At this time, the output voltage and the output DC are detected by the DC voltage detection circuit 6 and the DC current detection circuit 7, and the error amplifiers EA1 and EA2 set the set voltage circuit 17,
Compared with the output of 18, the duty ratios of the oscillation outputs E1 and E2 are changed and controlled so that the voltage and current do not exceed the set level. 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 and 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 frequency of 400 Hz and outputs a two-phase clock signal which is alternately turned on to the drive circuit 20. Drive circuit
Reference numeral 20 is a circuit for driving the bridge inverter by receiving the output of the oscillation circuit 19, and the outputs are transistors Q1 and Q.
The pair of switching transistors Q1 and Q4, which are connected to the gates of Q2, Q3 and Q4 and are diagonally opposed to each other, and the switching transistors Q2 and Q3, when one Q1 and Q4 are simultaneously turned on, the other Q2 and Q3 are simultaneously turned off. It is configured.

FIG. 4 is a circuit diagram showing a main part of the starting circuit 4. In FIG. 4, the starting circuit 4 includes a pulse transformer 21 having a secondary winding connected to the output of the inverter circuit 2 and a transistor 22 connected to the primary winding of the pulse transformer 21.
And a pulse generator circuit configured to include a series circuit, a oscillator 23 that starts oscillation upon receiving a control signal b from the lighting control circuit 8, and a buffer circuit 24 that switches the transistor 22 by the output of the oscillator 23. .. Pulse transformer
The discharge lamp 5 is connected to the other end of the secondary winding 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 includes a DC power source 1
Lighting discrimination circuit for discriminating lighting of the discharge lamp 5 in response to the output of the DC voltage detection circuit 6a for detecting the output voltage VDC of
25, the output of the DC voltage detection circuit 6b for detecting 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 described later, and the error amplifier EA2 of the IC 15 of the DC power supply 1 The power control circuit 26 that inputs a signal to control the output power of the DC power supply 1, 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 is longer, and the lighting determination circuit 25 A starting power signal setting trigger circuit 28 that triggers the output of the extinction time circuit 27 when the discharge lamp 5 is lit upon receiving the output, and an electric power immediately after the discharge lamp 5 is started by receiving the output of the extinction time circuit 27. After setting the level, the starting power signal circuit 29 that outputs a signal to reduce the starting power level to the power control circuit 26 with the passage of time and the input voltage of the starting power signal circuit 29 when the discharge lamp is started are reset. That a reset circuit 35, a starting power calculation circuit 100 for calculating the starting power corresponding to the output voltage of the DC power source 1 corresponding to the lamp voltage, constant switching circuit when switching the reduction time constant of starting power at a given lamp voltage
Equipped with 108. Further, the turn-off time circuit 27 and the starting power signal setting trigger circuit 28 constitute starting initial power setting means.

The lighting determination circuit 25 determines the output voltage V of the DC power supply 1.
Output voltage and setting of DC voltage detection circuit 6a for detecting DC
Compare the output voltage of the circuit 31 with the comparator COMP1
LO when the output voltage of the DC power supply 1 is higher than a predetermined voltage
W, if the voltage is lower than the predetermined voltage, the HIGH control signal b
Output. This control signal b enters the oscillator 23 of the starting circuit 4.
When activated, it produces a start pulse. Also
Input to the power control circuit 26 when the control signal b is LOW
The output of the DC voltage detection circuit 6b is output by the transistor Q6.
Short circuit and set the output of operational amplifier OP1 to 0V
It is designed to allow a large current to flow even when the voltage rises. This
As a result, during the period when the starting pulse is generated, the DC power supply 1
Operate the error amplifier EA1 in IC15
Can be brought to a constant voltage required for starting. In addition, the control signal b
Is LOW, the transistor Q9 of the reset circuit 35 is
Is turned on, the voltage of the capacitor C29 of the starting power signal circuit 29
V _c29 To reset.

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 discrimination circuit 25 becomes HIGH. Therefore, the operation of the starting circuit 4 is stopped and the starting pulse is stopped. Further, the transistor Q6 of the power control circuit 26 is turned off, and the output of the DC voltage detection circuit 6b in the power control circuit 26 becomes valid. Inputs the output V _6b of the DC voltage detecting circuit 6b, starting power calculation circuit 100 decreases the output signal with the increase of the lamp voltage is less than a predetermined lamp voltage, the predetermined lamp voltage or the output signal to zero.

FIG. 6 shows the input voltage V of the starting power calculation circuit 100.
It is a figure which shows the relationship between _6b and output voltage _Vc29 . Resistance R10
Bias voltage is applied by 1 and R102, and operational amplifier OP
It is inverted and amplified at 5. Above the input voltage V _6b ′ shown in FIG. 6, the output is set to 0V by the diodes 106 and 107. Thus, the higher the lamp voltage, the lower the starting power.

When the control signal b becomes HIGH, the transistor Q7 is turned on in the starting power signal setting trigger circuit 28 for a time determined by the capacitor C28 and the resistor R28.
Then, the trigger signal for setting the output of the starting power signal setting trigger circuit 28 to 0V is output. The starting power signal setting trigger circuit 28 controls the control signal b output from the lighting determination circuit 25.
The trigger signal is output in response to this, but the trigger signal may be output by detecting the turning on of the DC power supply 1. Alternatively, the time from when the DC power supply 1 is turned on until the lamp is lit It's good if it's in between.

The turn-off 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 outputs the output of the bias circuit 32 and the trigger power signal setting trigger with the operational amplifier OP3. The output of the circuit 28 is added, inverted and amplified, and output. Since the output of the starting power signal setting trigger circuit 28 is normally HIGH, the output of the operational amplifier OP3 is negative and does not affect the starting power signal circuit 29 due to the presence of the diode 33, but the starting power signal setting trigger circuit is When the output of 28 becomes 0V, the operation of the bias circuit 32 that outputs a negative bias voltage and the operational amplifier OP3 causes the operational amplifier OP3 to output a higher voltage as the output voltage of the operational amplifier OP2 decreases according to the output of the operational amplifier OP2. That is, as the turn-off time becomes longer and the voltage of the integrating circuit of R27 and C27 becomes lower, the output voltage of the turn-off time circuit 27 can be made higher.

The starting power signal circuit 29 receives the output of the starting power calculation circuit 100 and the output of the extinguishing time circuit 27 to charge the higher voltage to the capacitor C29, and this voltage is supplied to the power via the buffer amplifier OP4. Output to the control circuit 26. Since the lamp voltage of the capacitor C29 is low immediately after starting after the long extinguishing time, the output voltage of the starting power calculating circuit 100 is made high at this time. At this time, since the turn-off time is long, the output voltage of the turn-off time circuit 27 also increases.
The output voltage of 0 is higher. When the extinguishing time is short, the lamp voltage remains high. At this time, the output of the starting power calculation circuit 100 is low, and particularly when it is equal to or higher than the predetermined lamp voltage, it is set to 0V. Even in such a case, the output of the light-off time circuit 27 is equal to or more than a predetermined value
Further, the longer the turn-off time, the larger the value.

Since this is done, when the output of the starting power calculation circuit 100 is small because the turn-off time is short,
The output of the turn-off time circuit 27 controls the power through the starting power signal circuit 29 and the power control circuit 26, and the starting power according to the turn-off time can be input to the discharge lamp. In addition, when the output of the starting power calculation circuit 100 is larger than that of the off time circuit 27 because the turn-off time is long, the starting power calculation circuit 100
It is possible to control the electric power through the starting electric power signal circuit 29 and the electric power control circuit 26 by the output of, and input the starting electric power according to the lamp voltage to the discharge lamp.

FIG. 7 is a characteristic diagram of lamp voltage (V) -lamp power (W). In FIG. 7, a large lamp power is obtained and inputted at a predetermined lamp voltage V ', which is the starting region of the lamp, and the constant lamp power is supplied at a predetermined lamp voltage V', which is the stable lighting region of the lamp. Control to enter. Therefore, the lamp power can be reliably controlled, a large amount of lamp power can be input at the time of starting, and the lamp can be quickly and stably lit, and at the time of stable lighting, the lamp power can be made substantially constant and can be lit at the rated lamp power.

Immediately after starting, the output voltage is output from the starting power calculation circuit 100 or the extinguishing time circuit 27 to charge the capacitor C29, but thereafter, with the passage of time, it is discharged by the resistor R29 and gradually decreases. Therefore, the output of the starting power signal circuit 29 gradually decreases. Also, the time constant switching circuit
By 108, the time constant is switched so that the time constant of the decrease in the lamp power is increased when the lamp voltage exceeds a predetermined voltage. That is, when the lamp voltage is higher than the predetermined voltage, the output of the DC voltage detection circuit 6b and the resistance R
109, the voltage determined by R110 and the comparator COMP2
In comparison, the discharge time constant is increased by turning off the transistor Q8 and releasing the resistor R111. By increasing the time constant when the lamp voltage becomes equal to or higher than the predetermined voltage, the lamp power further slows down the rate of decrease as shown by the alternate long and short dash line in FIG. After the output, it can be switched to stable lighting without a large fluctuation.

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 of the above is inverted and amplified by the operational amplifier OP1, and the output is input to the negative input terminal of the error amplifier EA2 of the IC15 via the respective resistors. 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 control can be performed by this. In 26, a circuit is added to enable power control. By doing so, the power can be controlled by changing the ON duty ratio of the transistor 11 of the DC power supply 1 so that the current input to the negative input terminal of the error amplifier EA2 becomes 0 by these four signals.

The output of the DC current detection circuit 7 shown in FIG.
In addition to the output of the set voltage circuit 18, by inputting the output obtained by inverting and amplifying the divided output of the DC power supply 1 by the operational amplifier OP1, a negative signal corresponding to the DC current and a negative signal corresponding to the DC voltage are added. Positive set voltage circuit with constant result
It is controlled to match the output voltage of 18, and the output of the DC power supply 1 can be made approximately constant power within a certain current / voltage range, and the power input to the discharge lamp 5 via the inverter circuit 2 also becomes constant. be able to.

Further, by inputting the output of the starting power signal circuit 29, the DC voltage detecting circuit 6 corresponding to the lamp voltage at the start is compared with the rated power determined by the set voltage circuit 18.
Depending on the output of the starting power calculation circuit 100 according to the output of b or the output of the turn-off time circuit 27 according to the turn-off / light-on time, whichever is larger, the lower the lamp voltage or the longer the turn-off time is 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 lamp voltage or the extinction / lighting time to promptly start the light output, and the start of the discharge lamp 5 is started. It is possible to prevent the light output from being excessively output by controlling the lamp power to gradually approach the rated power and perform the rated lighting with the passage of time.

The signal corresponding to the DC current and the signal corresponding to the DC voltage are added here, and the result is controlled to a predetermined value so that the lamp can be approximately lit 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 so that the result is a predetermined value so that lighting is performed with a predetermined power. Nor.

The control characteristics of the starting power calculation circuit 100 and the time constants of the turn-off time circuit 27, the starting power signal circuit 29, and the time constant switching circuit 108 are such that the light output rises quickly and the light output after start becomes large. It goes without saying that you need to choose not to pass.

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 / DC converter are used.
Other DC power supplies such as a converter may be used, and the inverter circuit may be an inverter of another type such as a half-bridge type or push-pull type.

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 has been shown, but the present invention is not limited to this, as long as the discharge lamp does not cause harmful phenomena such as electrophoresis and acoustic resonance. Other lighting devices such as a high frequency lighting device and a direct current lighting device may be used.

[0041]

As described above, according to the present invention, when the lamp voltage detecting means detects a low lamp voltage in the starting region of the discharge lamp, the output of the lamp current supplying means is controlled to generate a large lamp power. When a high lamp voltage is detected, a small lamp power is supplied by controlling the output of the lamp current supply means, so that the lamp power can be reliably controlled and the lamp can be lit at the rated lamp power during stable lighting.

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. Since harmful electrophoretic and acoustic resonance phenomena can be reduced or substantially eliminated, and the lighting control means controls the output of the lamp current supply means by controlling the output of the DC power supply. Furthermore, the output voltage of the DC power supply is detected instead of the lamp voltage, the output current of the DC power supply is detected instead of the lamp current, and the output of the DC power supply is controlled to control the output of the lamp current supply means. Since it is set, detection and control can be facilitated.

Further, when the voltage is less than the predetermined lamp voltage, the output signal decreases with an increase in the lamp voltage, and when the voltage is higher than the predetermined lamp voltage, there is provided lamp power calculating means and bias means, and the lamp power calculating means. Since the output of the lamp current supply means is controlled by the addition output of the bias means and a predetermined lamp voltage in the starting region of the lamp, a large lamp power at the time of starting is input to quickly increase the luminous flux of the discharge lamp. , It lights at the rated power when the lamp voltage is higher than a predetermined level.

Further, when the lamp voltage becomes equal to or higher than a predetermined voltage, the time constant switching means switches the time constant so as to increase the time constant of the decrease of the lamp power in the lamp power calculation means, and the lamp power is changed to a large time constant. Since the rated lighting is gradually changed, the light output after the start can be changed to the stable lighting without a large change after the rated output.

Further, immediately after starting and restarting, the initial lamp power is set so that a predetermined lamp power that is at least larger than the lamp power during stable lighting is flown, and particularly when restarting, the lamp voltage is set to the lamp voltage during stable lighting. Even in a similar case, by inputting a large lamp power, even if the enclosed metal adheres to the tube wall of the lamp when the lamp is turned off, a light output close to that during stable lighting can be obtained immediately after restart.

Further, the initial lamp power is set so that a predetermined lamp power larger than the lamp power at least during stable lighting is input immediately after starting / restarting according to the output of the lighting-off time detecting means, and the turning-off time is short. By setting the initial lamp power to be larger when the lamp is longer than when it is used, the luminous efficiency does not decrease because the vapor pressure of the enclosed metal does not decrease when the extinguishing time is short, and the enclosed lamp is also enclosed. Since the degree of adhesion of metal to the tube wall is low, in such a case, a large amount of lamp power is not supplied at the time of restart, and conversely the vapor pressure decreases and the adhered metal adheres to the tube wall as the extinguishing time increases. In this case, a large lamp power can be input at the time of restart since the influence becomes large, and a light output close to that at stable lighting can be obtained immediately after restart.

[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 diagram showing a main part of a DC power source in the discharge lamp lighting device according to the embodiment of the present invention.

FIG. 3 is a circuit diagram showing a main part of an inverter circuit in a discharge lamp lighting device according to an embodiment of the present invention.

FIG. 4 is a circuit diagram showing a main part of a starting circuit in the discharge lamp lighting device according to the embodiment of the present invention.

FIG. 5 is a circuit diagram showing a main part of a lighting control circuit in the discharge lamp lighting device according to the embodiment of the present invention.

FIG. 6 is a characteristic diagram of a starting power calculation circuit in the lighting control circuit.

FIG. 7 is a lamp voltage-lamp power characteristic diagram of the lighting control circuit.

[Explanation of symbols]

 1 DC power supply 2 Inverter circuit 3 Lamp current supply means 4 Starting circuit 5 Discharge lamp 6, 6a, 6b DC voltage detection circuit 7 DC current detection circuit 8 Lighting control circuit 25 Lighting discrimination circuit 26 Power control circuit 27 Off time circuit 28 Starting power Signal setting trigger circuit 29 Starting power signal circuit 35 Reset circuit 100 Starting power calculation circuit 108 Time constant switching 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 Nobuhisa Yoshikawa 1006, Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Saito Takeshi Kadoma, Osaka Prefecture 1006 Kadoma, Matsushita Electric Industrial Co., Ltd. (72) Inventor Kazuhiko Ito Osaka 1006 Kadoma, Kadoma-shi, Matsushita Electric Industrial Co., Ltd. (72) Inventor Masayoshi Kyoten, 1006 Kadoma, Kadoma-shi, Osaka Prefecture (72) In Matsushita Electric Industrial Co., Ltd. Denki Sangyo Co., Ltd.

Claims (8)

[Claims] 1. A lamp current supply means, a discharge lamp connected to the lamp current supply means, a lamp voltage detection means for detecting a lamp voltage, a lamp current detection means for detecting a lamp current, and a lamp voltage detection means. And a power control means for controlling the lamp power by receiving the output of the lamp current detection means, and the output voltage of the lamp voltage detection means in the lamp starting region is input, and controls the lamp current supply means when the lamp voltage is low. Large lamp power is input to the discharge lamp, and when the lamp voltage is high, the lamp current supply means is controlled to input a small lamp power to the discharge lamp,
A discharge lamp lighting device, comprising: lighting control means for controlling the discharge lamp to be rated lighting after the lamp starting region. 2. The discharge lamp lighting device according to claim 1, wherein the lamp current supply means includes a DC power supply and an inverter means driven by the DC power supply to oscillate. 3. The discharge lamp lighting device according to claim 2, wherein the lighting control means controls the output of the lamp current supply means by controlling the output of the DC power supply. 4. The output of the lamp current supply means is controlled by detecting the output voltage of the DC power supply by the lamp voltage detection means, detecting the output current of the DC power supply by the lamp current detection means, and controlling the output of the DC power supply. The discharge lamp lighting device according to claim 3, wherein 5. The lighting control means includes a lamp power calculation means for decreasing the output signal with an increase in the lamp voltage when the voltage is less than a predetermined lamp voltage, and a zero for the output signal when the voltage is higher than the predetermined lamp voltage, and a bias means. 5. The discharge lamp lighting device according to claim 1, wherein the output of the lamp current supply means is controlled by the addition output of the lamp power calculation means and the bias means. 6. The lighting control means has a time constant switching means which is connected to the lamp power calculation means and operates at a predetermined lamp voltage, and when the lamp voltage becomes equal to or higher than a predetermined voltage, the lamp power of the lamp power calculation means. 6. The discharge lamp lighting device according to claim 5, wherein the time constant is switched so as to increase the time constant of decrease with respect to. 7. The lighting control means comprises a starting initial power setting means for setting the initial lamp power so that a predetermined lamp power larger than the lamp power at least during stable lighting is flowed immediately after starting and restarting. 2. The discharge lamp lighting according to claim 1, wherein the larger one of the initial lamp power and the starting power according to the lamp voltage, whichever is larger, is input to the discharge lamp, and the discharge lamp is controlled to be rated after the lamp starting region. apparatus. 8. The starting initial power setting means is greater than the lamp power at the time of stable lighting immediately after starting / restarting according to the output of the extinguishing time detecting means for detecting the extinguishing time of the lamp and the output of the extinguishing time detecting means. The lighting control means is provided with a starting power signal setting trigger means capable of setting the initial lamp power so that a larger lamp power is supplied as the turning-off time becomes longer, and the lighting control means has a larger starting power depending on the turning-off time and the starting voltage. The discharge lamp lighting device according to claim 7, wherein the other lamp power is input to the discharge lamp, and the discharge lamp is controlled to be rated after the lamp starting region.