JP2010055829A - Metal halide lamp lighting device, and headlight and vehicle using the same - Google Patents

Abstract

A high-frequency noise from a metal halide lamp is rapidly reduced by promoting generation of free iodine in the metal halide lamp.
A lamp power control unit 6 measures a cumulative lighting time measuring unit 61 that measures a cumulative lighting time of a metal halide lamp La, and controls a magnitude of lamp power according to a measurement result of the cumulative lighting time measuring unit 61. And a control unit 62. The control unit 62 sets the lamp power to a value higher than the rated value during the aging period until the cumulative lighting time reaches zero to a certain time, and sets the lamp power to the rated value during the normal period after the aging period. To do. Thereby, in the aging period, the reaction between the metal halide generated in the metal halide lamp La and the glass is promoted, and free iodine is generated at an accelerated rate.
[Selection] Figure 1

Description

  The present invention relates to a metal halide lamp lighting device for lighting a metal halide lamp, a headlamp using the same, and a vehicle.

  Conventionally, as a metal halide lamp lighting device for lighting a metal halide lamp that is a kind of high-intensity discharge lamp used for spotlights, projector light sources, vehicle headlamps, etc., avoiding acoustic resonance, etc. For this purpose, it is known that a metal halide lamp is lit by a low-frequency rectangular wave.

  This type of metal halide lamp lighting device includes a main circuit that generates a lamp voltage that has a rectangular wave shape and reverse polarity, and the lamp is output by applying the lamp voltage output from the main circuit to the metal halide lamp. .

However, in the method of lighting a metal halide lamp with a rectangular wave in this way, the current that flows through the metal halide lamp (hereinafter referred to as the lamp current) instantaneously becomes zero when the polarity of the lamp voltage is reversed. There is a problem that high-frequency noise is generated during the process. In order to reduce this high-frequency noise, there is an experimental result that it is effective to raise the electrode temperature in order to facilitate re-ignition. FIG. 10 shows the lamp current waveform with the horizontal axis as the time axis. Thus, a countermeasure is considered in which the lamp current is temporarily increased before polarity inversion (FIG. 10A) and before and after polarity inversion (FIGS. 10B to 10D) (for example, Patent Document 1, 2). For example, when the lamp current is increased before polarity inversion as shown in FIG. 10A, it is confirmed that the electrode temperature at the time of polarity inversion can be kept high, and high frequency noise generated from the metal halide lamp at the time of polarity inversion can be reduced. ing.
Japanese National Patent Publication No. 10-501919 JP 2002-110392 A

  However, if the control is performed to increase the lamp current when the polarity of the lamp voltage is inverted as described above, the light output of the metal halide lamp varies instantaneously while the lamp current is increasing. As a result, if the metal halide lamp itself is stationary, the increase or decrease of the light output will not be recognized, but if the metal halide lamp itself moves at high speed, such as in a car, it will cause flickering etc. It becomes. As another means of reducing high frequency noise generated from a metal halide lamp, it is conceivable to suppress the temperature drop of the electrode by increasing the speed of polarity reversal, but in this case, the increase in noise generated from the main circuit or As a result, the burden on the circuit elements increases and the reliability of the main circuit cannot be ensured.

  By the way, it has been found that the high frequency noise generated when the polarity of the lamp voltage is reversed is reduced as the cumulative lighting time of the metal halide lamp elapses. FIG. 11 is considered to be caused by the polarity inversion of the lamp voltage for three types of on-vehicle metal halide lamps (lamp 1 to lamp 3) in which sodium iodide (NaI) is sealed in the arc tube as a metal halide (metal halide). It shows an example of a time-dependent change of high-frequency noise (about 400 kHz), and shows that the noise peak value (vertical axis) decreases as the cumulative lighting time (horizontal axis) elapses. Such a decrease in noise level is released with the progress of the reaction between the metal halide (here, sodium iodide) and the glass forming the arc tube in the arc tube of the metal halide lamp as the cumulative lighting time elapses. Due to an event that iodine (hereinafter referred to as free iodine) increases, the arc generated in the arc tube becomes thinner, the hot spot (bright spot) formed on the cathode side electrode becomes smaller, and the spot temperature rises Presumed to be. That is, when free iodine increases, the electrode temperature increases, so that hot spots are likely to be formed during polarity reversal, and high-frequency noise is reduced.

  The present invention has been made in view of the above reasons, and a metal halide lamp lighting device capable of promptly reducing high-frequency noise from a metal halide lamp by promoting the generation of free iodine in the metal halide lamp and the use thereof. The purpose is to provide a headlamp and a vehicle.

  According to the first aspect of the present invention, the main circuit for lighting the metal halide lamp by applying a lamp voltage to the metal halide lamp so that the direction of the current flowing between the pair of electrodes of the metal halide lamp is alternately reversed, and the cumulative lighting of the metal halide lamp A lamp power control unit that variably controls the power supplied to the metal halide lamp according to the time, and the lamp power control unit is configured to perform an aging period from zero to a certain time after the aging period ends. The supplied power is controlled such that the amount of power supplied to the metal halide lamp per unit time is larger than that in the normal period.

  According to this configuration, the power control unit is configured to supply the metal halide lamp to the metal halide lamp during the aging period until the cumulative lighting time of the metal halide lamp reaches a certain time from zero, compared to the regular period after the aging period ends. Since the supplied power is controlled so as to increase the amount of power per hit, the reaction between the metal halide and the glass generated in the arc tube of the metal halide lamp is promoted during the aging period. That is, since the degree of reaction in the arc tube of the metal halide lamp is strongly dependent on the operating temperature of the metal halide lamp, increasing the amount of power supplied to the metal halide lamp can accelerate the reaction and accelerate the generation of free iodine. it can. As a result, the noise level of the high frequency noise generated at the time of reversing the polarity of the lamp voltage can be quickly reduced during the aging period, and the high frequency noise can be maintained at a low level during the subsequent normal period.

  According to a second aspect of the present invention, in the first aspect of the invention, the lamp power control unit sets the power supplied to the metal halide lamp to a rated value during the regular period, and is higher than the rated value during the aging period. It is characterized by setting.

  According to this configuration, since the power supplied to the metal halide lamp is set to the rated value during the normal period, it is possible to avoid excessive reaction from proceeding in the arc tube of the metal halide lamp after the aging period ends. There are advantages.

  According to a third aspect of the present invention, in the first aspect of the invention, the lamp power control unit is configured so that the power supplied to the metal halide lamp is lower than the rated value in the startup operation from the start of the metal halide lamp to the transition to steady lighting. The holding power is held at a high starting power for the holding time, and is lowered to the rated value after the holding time has elapsed. The holding time is set longer in the aging period than in the normal period.

  According to this configuration, in the start-up operation from the start of the metal halide lamp to the transition to steady lighting, the reaction within the arc tube of the metal halide lamp is promoted by controlling the power supplied to the metal halide lamp. The control of the power supplied by the lamp power control unit does not affect the lighting state of the metal halide lamp during steady lighting.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the lamp power control unit is configured to change electricity in relation to the cumulative lighting time of the metal halide lamp among the electrical characteristics of the metal halide lamp. It has a cumulative lighting time discriminating unit for monitoring the characteristics and discriminating the cumulative lighting time from the monitoring result.

  According to this configuration, since the cumulative lighting time is determined from the monitoring result of the electrical characteristics of the metal halide lamp, the cumulative lighting time is reset when the lamp is replaced without providing a function for resetting the cumulative lighting time. Simplification can be achieved.

  According to a fifth aspect of the present invention, there is provided the metal halide lamp lighting device according to any one of the first to fourth aspects, the metal halide lamp that is turned on when a lamp voltage is applied from the metal halide lamp lighting device, and the metal halide lamp. And a lamp body to be held.

  According to this configuration, in the headlamp, high-frequency noise from the metal halide lamp can be quickly reduced by promoting the generation of free iodine in the metal halide lamp, so that the lamp current at the time of polarity reversal of the lamp voltage can be reduced. There is no problem that the light output of the metal halide lamp fluctuates and flickers during running as in the conventional example in which the high frequency noise is reduced by increasing.

  The invention of claim 6 is characterized in that the headlamp according to claim 5 is provided in a vehicle body.

  According to this configuration, in the vehicle, high-frequency noise from the metal halide lamp can be quickly reduced by promoting the generation of free iodine in the metal halide lamp, so that the lamp current at the time of reversing the polarity of the lamp voltage is increased. Thus, unlike the conventional example in which high frequency noise is reduced, there is no problem that the light output of the metal halide lamp fluctuates and flickering is felt during traveling.

  According to the present invention, the amount of power supplied to the metal halide lamp within the predetermined time period during the aging period until the cumulative lighting time of the metal halide lamp reaches a predetermined time from zero is less than the normal period thereafter. Since the supplied power is controlled so as to increase, the reaction between the metal halide (metal halide) generated in the arc tube of the metal halide lamp and the glass is promoted during the aging period. As a result, there is an advantage that the noise level of the high frequency noise generated at the time of reversing the polarity of the lamp voltage can be quickly reduced, and the high frequency noise can be maintained at a low level in the subsequent normal period.

(Embodiment 1)
A metal halide lamp lighting device (hereinafter simply referred to as “lighting device”) A according to the present embodiment converts a DC voltage from a DC power source 1 into a magnitude required by the metal halide lamp La, as shown in FIG. DC-DC converter 2, inverter circuit 3 that converts the output (DC voltage) of DC-DC converter 2 into a low-frequency rectangular wave lamp voltage, and an igniter that generates a voltage of several tens of kV when the metal halide lamp La is started The main circuit includes a circuit 4 and a drive unit 5 that monitors the output voltage (lamp voltage) and output current (lamp current) of the inverter circuit 3 and controls the DC-DC converter 2 so that the output power becomes the target power. ing.

  Here, the DC-DC converter 2 is a flyback converter, and a series circuit of the primary winding P1 of the transformer T1 and the switching element Q1 is connected between both ends of the DC power source 1, and the secondary winding of the transformer T1. A series circuit of a diode D1 and a smoothing capacitor C1 is connected between both ends of the line S1. The diode D1 prevents the current generated in the secondary winding S1 of the transformer T1 from flowing into the smoothing capacitor C1 when the switching element Q1 is turned on and a voltage is applied to the primary winding P1 of the transformer T1. Inserted in the direction.

  The inverter circuit 3 is a full bridge circuit configured by connecting a series circuit of switching elements Q2 and Q4 and a series circuit of switching elements Q3 and Q5 in parallel between both ends of the smoothing capacitor C1 of the DC-DC converter 2. Consists of. Thus, by alternately turning on the group of switching elements Q2 and Q5 and the group of switching elements Q3 and Q4, an alternating voltage is generated between the connection point of switching elements Q2 and Q4 and the connection point of switching elements Q3 and Q5. (Lamp voltage) is generated. However, before starting the metal halide lamp La, the switching elements Q2 and Q5 are fixed to the on state and the switching elements Q3 and Q4 are fixed to the off state.

  The igniter circuit 4 includes a transformer T2, a spark gap SG1 connected in series with the primary winding P2 of the transformer T2, and a capacitor Cs. The igniter circuit 4 is connected between the output terminals of the inverter circuit 3 (the switching elements Q2 and Q4). A series circuit of the primary winding P2 of the transformer T2 and the spark gap SG1 and the capacitor Cs are connected in parallel between the connection point and the connection point of the switching elements Q3 and Q5. Here, the secondary winding S <b> 2 of the transformer T <b> 2 is connected in series with the metal halide lamp La, and is connected between the output ends of the inverter circuit 3.

  Next, the basic operation of the lighting device A configured as described above will be described.

  When the lighting device A is turned on and the switching element Q1 of the DC-DC converter 2 is turned on, a current flows through a series circuit of the primary winding P1 of the transformer T1 and the switching element Q1. At this time, since the current that attempts to flow through the secondary winding S1 of the transformer T1 is blocked by the diode D1, the energy generated by the current flowing through the primary winding P1 is stored in the transformer T1. Next, when the switching element Q1 is turned off, a current flows through the path of the secondary winding S1, the smoothing capacitor C1, and the diode D1 of the transformer T1, and the energy stored in the transformer T1 is transferred to the smoothing capacitor C1.

  Here, since the metal halide lamp La is in an open state before the metal halide lamp La is started (before discharge is started), the output voltage of the DC-DC converter 2 (the voltage across the smoothing capacitor C1) is obtained by repeating the above operation. Gradually rises. At this time, since the switching elements Q2 and Q5 are fixed in the inverter circuit 3 and the switching elements Q3 and Q4 are turned off, the voltage across the capacitor Cs also increases. When the voltage across the capacitor Cs reaches the breakdown voltage of the spark gap SG1, the spark gap SG1 breaks down, a voltage is instantaneously applied to the primary winding P2 of the transformer T2, and the secondary winding S2 of the transformer T2 Therefore, a high voltage obtained by multiplying the above voltage by the turns ratio of the transformer T2 is generated. This high voltage (about several tens of kV) causes the metal halide lamp La to break down. At that moment, a current flows from the DC-DC converter 2 to the metal halide lamp La via the inverter circuit 3, and the metal halide lamp La shifts to arc discharge.

  By the way, the lighting device A of the present embodiment controls lamp power control for controlling the power supplied to the metal halide lamp La (hereinafter referred to as lamp power) according to the cumulative lighting time of the metal halide lamp La as shown in FIG. Part 6 is provided.

  The lamp power control unit 6 controls the magnitude of the lamp power according to the cumulative lighting time measuring unit 61 that measures the cumulative lighting time of the metal halide lamp La and the measurement result (cumulative lighting time) in the cumulative lighting time measuring unit 61. And a reset switch 63 for resetting the cumulative lighting time measured by the cumulative lighting time measuring unit 61 to zero when the metal halide lamp La is replaced. Here, the cumulative lighting time measuring unit 61 monitors the operating time of the inverter circuit 2 and measures the cumulative lighting time on the assumption that the cumulative value is equal to the cumulative lighting time of the metal halide lamp La. In addition, the control unit 62 controls the magnitude of the lamp power by changing the lamp current by controlling the switching elements Q2 to Q5 of the inverter circuit 2.

  Here, as shown in FIG. 2, the control unit 62 converts the lamp power into the rated power value (rated value) of the metal halide lamp La during the period until the cumulative lighting time reaches a certain time from zero (hereinafter referred to as the aging period t1). ), The lamp power is decreased when the predetermined time is reached, and the lamp power is set to the rated power value of the metal halide lamp La in the subsequent period (hereinafter referred to as the regular period t2).

  Thereby, in the aging period t1, the amount of electric power per a certain time supplied to the metal halide lamp La is larger than that in the regular period t2 after the aging period t1, and the metal halide generated in the arc tube of the metal halide lamp La. The reaction between the sodium iodide (herein referred to as sodium iodide) and the glass forming the arc tube is promoted to liberate iodine (hereinafter referred to as free iodine) at an accelerated rate. At this time, as shown in FIG. 3, the lamp voltage rises steeply as free iodine is rapidly generated, and during the subsequent normal period t2, the rate of increase at the rated lighting at the rated power is relatively slow. To rise.

  Here, the noise level of the high frequency noise generated in the metal halide lamp La at the time of reversing the polarity of the lamp voltage rapidly decreases during the aging period t1 set at the beginning of lighting as shown in FIG. 4, and during the subsequent regular period t2. It has been confirmed that a low noise level is maintained. After such a low noise state is realized, the lamp power is set to the rated value in order to avoid excessive generation of free iodine, so that it is possible to avoid a practical problem.

  That is, the degree of the reaction that occurs in the arc tube of the metal halide lamp La strongly depends on the operating temperature of the metal halide lamp La. Therefore, as described above, during the aging period t1, the amount of electric power supplied to the metal halide lamp La is reduced. By increasing the operating temperature of the metal halide lamp La, it is possible to accelerate the reaction and generate free iodine at an accelerated rate. As free iodine increases, the arc generated in the arc tube becomes thinner, and the hot spot (bright spot) formed on the cathode electrode becomes smaller and the spot temperature rises. Therefore, hot spots are easily formed during polarity reversal. It is considered that high frequency noise is reduced. On the other hand, in the regular period t2, it is possible to avoid the generation of free iodine by excessive reaction by lowering the lamp power to the rated value and lowering the operating temperature of the metal halide lamp La.

  When the metal halide lamp La is replaced and the reset switch 63 is operated, the accumulated lighting time is reset and counted again from zero, so that the lamp power control shown in FIG. 2 is repeated. In this embodiment, the cumulative lighting time is reset by the operation of the reset switch 63. However, for example, a means for detecting the attachment / detachment of the metal halide lamp La is provided, and the cumulative lighting time is automatically reset when the lamp is replaced. It is also possible.

  In the present embodiment, the lighting device A for lighting the metal halide lamp La in which sodium iodide (NaI) is enclosed in the arc tube as the metal halide (metal halide) is illustrated, but the present invention is not limited to sodium iodide. The present invention can be applied to a lighting device A used for lighting a metal halide lamp La enclosing various metal halides. Even when a general metal halide lamp La in which a metal halide other than sodium iodide is sealed is used, according to the present invention, the reaction in the arc tube is promoted to generate free halogen (free halogen). Can be promoted.

(Embodiment 2)
The lighting device A of the present embodiment is different from the lighting device A of the first embodiment in that the lamp power control unit 6 controls the lamp power in the startup operation from the start of the metal halide lamp La to the steady lighting. Is different.

  In general, in the start-up operation of the metal halide lamp La, as illustrated in FIG. 5, the lamp power higher than the rated power value (hereinafter referred to as starting power) from the start (discharge start) of the metal halide lamp La to a predetermined holding time. When the holding time has elapsed, the lamp power is controlled to be swept from the starting power to the rated power value of the metal halide lamp La. In particular, in the case of an in-vehicle metal halide lamp La used for a headlamp or the like, a high-speed start-up is required, and a holding time of about several seconds from the start of the metal halide lamp La is used as a starting power that is nearly twice the rated power value. It is controlled so that it is supplied over the range.

  In this embodiment, the reaction in the arc tube of the metal halide lamp La is promoted by lengthening the holding time of the starting power in the start-up operation described above in the aging period t1 set at the beginning of lighting. Thereby, since a reaction is accelerated | stimulated during start-up operation, there exists a merit that the influence on a user can be made small compared with the case where a reaction is accelerated | stimulated during steady lighting.

  Specifically, as illustrated in FIG. 6, during the period until the cumulative lighting time of the metal halide lamp La reaches a certain time from zero (aging period t1), the holding time of the starting power in the start-up operation is rated. When the time T ′ is set longer than T and the cumulative lighting time reaches the predetermined time, the holding time of the starting power in the start-up operation is changed to the rated value T in the subsequent period (normal period t2). Here, the starting power is set to twice the rated power, and the holding time becomes longer in the aging period t1 as shown by the broken line in FIG. 5, thereby effectively promoting the reaction in the arc tube of the metal halide lamp La. It becomes possible.

  Here, an example in which the holding time of the starting power is lengthened has been shown. However, the present invention is not limited to this example, and any configuration that can promote the reaction in the arc tube by controlling the lamp power during the start-up operation may be used. The reaction can also be promoted by means such as reducing the reduction rate of the lamp power after holding the power for the holding time (that is, increasing the time until the lamp power reaches the rated power value).

  Other configurations and functions are the same as those of the first embodiment.

(Embodiment 3)
As shown in FIG. 7, the lighting device A of the present embodiment includes an electrical characteristic measurement unit 64 that measures electrical characteristics of the metal halide lamp La (hereinafter, referred to as lamp electrical characteristics), and from the measurement result of the electrical characteristic measurement unit 64. The difference from the lighting device A of the first embodiment is that a cumulative lighting time discriminating unit 65 that determines the cumulative lighting time of the metal halide lamp La is provided in place of the cumulative lighting time measuring unit 61. The control unit 62 controls the lamp power according to the determination value (cumulative lighting time) in the cumulative lighting time determination unit 65.

  Here, the lamp electrical characteristic to be measured by the electrical characteristic measuring unit 64 only needs to be correlated with the cumulative lighting time of the metal halide lamp La. For example, the lamp voltage value or the lamp at the time of re-ignition of the metal halide lamp La is used. An example is the peak value of the voltage. It is also possible to measure electrical characteristics that are directly correlated with a reduction in high-frequency noise from the metal halide lamp La.

  According to the above configuration, the cumulative lighting time of the metal halide lamp La is not actually measured, but the cumulative lighting time is estimated from the lamp electrical characteristics. Therefore, when replacing the lamp, the electrical characteristics of the metal halide lamp La after the replacement are estimated. Accordingly, the cumulative lighting time is reset, and there is an advantage that the operation of the reset switch and the means for detecting the attachment / detachment of the metal halide lamp La become unnecessary.

  Other configurations and functions are the same as those in the first or second embodiment.

(Embodiment 4)
The lighting device A of the present embodiment is different from the lighting device A of the first embodiment in that an AC power source (commercial power source) AC is used as a power source instead of the DC power source 1 as shown in FIG.

  The lighting device A includes an AC-DC converter 7 that converts the output of the AC power source AC into a DC voltage and applies the DC voltage to the DC-DC converter 2. The AC-DC converter 7 connects a parallel circuit of a primary winding P3 of a transformer T3 and a capacitor C2 to an AC power source AC, and an inductor L1 and a capacitor C4 are connected between both ends of the secondary winding S3 of the transformer T3. A series circuit is connected, and the voltage across the capacitor C4 is full-wave rectified by a diode bridge DB, and then boosted by a boost chopper circuit.

  The step-up chopper circuit is connected between the capacitor C5 connected between the output ends of the diode bridge DB, the series circuit of the inductor L2 connected between both ends of the capacitor C5 and the switching element Q6, and both ends of the switching element Q6. A series circuit of a diode D2 and a capacitor C6 is provided, and the voltage across the capacitor C6 is applied to the subsequent DC-DC converter 2 as an output voltage. In FIG. 8, the DC-DC converter 2 employs a flyback converter as in the first embodiment, but a step-down chopper circuit may be employed instead.

  Here, the present invention for controlling the lamp power in accordance with the cumulative lighting time is a specific circuit configuration for a lighting device that turns on the metal halide lamp La with a rectangular wave and increases the output in synchronization with the rectangular wave. It is useful regardless of the input voltage value and the like, and even the lighting device A of the present embodiment can be expected to have the same effects as those of the first or second embodiment. As another circuit configuration, a circuit configuration using both the DC-DC converter 2 and the inverter circuit 3 is also known, and the same effect can be obtained by applying the present invention to such a circuit configuration. it can.

  Other configurations and functions are the same as those in the first or second embodiment.

  By the way, the lighting device A of each embodiment mentioned above comprises the headlamp 8 for vehicles as shown in FIG. 9 with the metal halide lamp La and the lamp body (not shown) holding the metal halide lamp La, for example. . This headlamp 8 is mounted on the vehicle body of the vehicle 9 as a pair of left and right, and is connected to a headlamp control device 10 provided separately on the left and right, so that a control signal from the low beam switch 11 is sent to the headlamp. Lights up in response to the control device 10.

  In the lighting device A used for this kind of vehicle-mounted metal halide lamp La, there are very strict regulations regarding safety and noise. By adopting the lighting device A of the present invention, noise is reduced. However, since the flicker due to the fluctuation of the light output of the metal halide lamp La can be suppressed as compared with the case where the control for increasing the current at the time of polarity reversal is performed as in the conventional configuration, the headlamp 8 has improved safety. In addition, the vehicle 9 can be realized.

It is a schematic circuit diagram which shows the structure of Embodiment 1 of this invention. It is explanatory drawing which shows the change of lamp electric power same as the above. It is explanatory drawing which shows the time change of a lamp voltage same as the above. It is explanatory drawing which shows the time change of a lamp current same as the above. It is explanatory drawing which shows control of the lamp electric power in the starting operation | movement of Embodiment 2 of this invention. It is explanatory drawing which shows the change of holding time same as the above. It is a schematic circuit diagram which shows the structure of Embodiment 3 of this invention. It is a schematic circuit diagram which shows the structure of Embodiment 4 of this invention. It is the schematic which shows the headlamp and vehicle which used the metal halide lamp lighting device of this invention. It is explanatory drawing which shows operation | movement of a prior art example. It is a graph which shows the change of the noise peak value with respect to accumulation lighting time.

Explanation of symbols

6 Lamp power control unit 8 Headlight 9 Vehicle 64 Cumulative lighting time discriminating unit A Metal halide lamp lighting device La Metal halide lamp t1 Aging period t2 Regular period

Claims (6)

  A main circuit for lighting the metal halide lamp by applying a lamp voltage to the metal halide lamp so that the direction of the current flowing between the pair of electrodes of the metal halide lamp is alternately reversed, and to the metal halide lamp according to the cumulative lighting time of the metal halide lamp A lamp power control unit that variably controls the supply power of the metal halide lamp in the aging period until the cumulative lighting time reaches a fixed time from zero compared to the regular period after the end of the aging period The metal halide lamp lighting device is characterized in that the supplied power is controlled so that the amount of power supplied per unit time is increased.   2. The metal halide lamp according to claim 1, wherein the lamp power control unit sets power supplied to the metal halide lamp to a rated value during the normal period and higher than a rated value during the aging period. Lighting device.   In the start-up operation from the start of the metal halide lamp to the transition to steady lighting, the lamp power control unit holds the power supplied to the metal halide lamp at a start power higher than the rated value for the holding time and after the holding time has elapsed. 2. The metal halide lamp lighting device according to claim 1, wherein the holding time is set longer in the aging period than in the normal period.   The lamp power control unit monitors an electrical characteristic that changes in relation to the cumulative lighting time of the metal halide lamp among the electrical characteristics of the metal halide lamp, and includes a cumulative lighting time determination unit that determines the cumulative lighting time from the monitoring result. The metal halide lamp lighting device according to claim 1, wherein the metal halide lamp lighting device is provided.   A metal halide lamp lighting device according to any one of claims 1 to 4, a metal halide lamp that is turned on when a lamp voltage is applied from the metal halide lamp lighting device, and a lamp body that holds the metal halide lamp. A headlamp characterized by that. A vehicle comprising the headlamp according to claim 5 in a vehicle body.

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