JPS5963654A - Metal halide lamp - Google Patents

Abstract

PURPOSE:To make arc discharge to be securely induced between main electrodes when high frequency high voltage is applied by crossing a main discharge path, formed between the main electrodes, and a minor discharge path, formed either between the main electrode and an auxiliary electrode or between a pair of auxiliary electrodes, within the tube. CONSTITUTION:Main electrodes (A) and (A') as well as auxiliary electrodes (C) and (C') are installed facing each other. A main discharge path formed between the main electrodes (A) and (A') crosses a minor discharge path formed between the auxiliary electrodes (C) and (C') almost at the center of the tube. When a commercial power source 1 is put to work, a high-frequency circuit 4 operates first, then high-frequency arc discharge is induced between the auxiliary electrodes (C) and (C') through terminals (p2) and (p3). When the high-frequency arc discharge develops between the electrodes (C) and (C'), since the main and the minor discharge paths cross each other, the conductivity of the main discharge path increases rapidly due to the arc discharge. As a result, arc discharge is produced in the main discharge path by means of the commercial power source 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (81) Field of the Invention This invention relates to a metal halide lamp containing a metal halide such as thallium iodide, which is used as a highly efficient coloring light source.

(b) Background of the Invention Metal halide lamps have the advantage of being a light source with high efficiency and high color rendering properties, but have the disadvantage that restarting is difficult because the internal pressure becomes extremely high after initial startup. Particularly when attempting to restart at a low frequency, it is necessary to apply a voltage of several tens of kilovolts or more with an inter-electrode gap of approximately several tens to several tens of ohms. However, in addition to the above-mentioned advantages as a light source, this type of lamp does not require restarting every half cycle, as is the case with fluorescent lamps, once restarted. In addition, if the restart is performed at a high frequency, the applied voltage can be applied for a few minutes.In view of the above, the present applicant installed a pair of main electrodes facing each other in the tube, With the auxiliary electrode facing each other, a low frequency voltage is applied between the main electrode and a high frequency high voltage is applied between the auxiliary electrode and the main electrode to first generate an arc discharge between the auxiliary type □ pole and the main electrode. Based on this, we proposed a metal halide lamp lighting device that generates an arc discharge between the main electrodes using low frequency and low voltage.

According to this metal halide lamp lighting device, since a high frequency high voltage is first applied between the main electrode and the auxiliary electrode,
Arc discharge easily occurs between both electrodes. When this arc discharge occurs, the conductivity between the main electrodes increases rapidly, and arc discharge is also induced between the main electrodes. When arc discharge occurs between the main electrodes, the highly excited state is maintained thereafter, so that arc discharge due to low frequency and low voltage is maintained between the main electrodes.

In this way, an arc discharge is first generated between the main electrode and the auxiliary electrode, which has the advantage of making restart very easy, but there is a possibility that restart will not occur reliably depending on the atmosphere inside the tube. There is.

That is, even if arc discharge occurs between the main electrode and the auxiliary electrode, the arc discharge may not cause arc discharge due to the low voltage between the main electrodes.

The above disadvantages can be solved by providing a pair of auxiliary electrodes inside the tube, first causing arc discharge between the auxiliary electrodes, and then inducing arc discharge between the pair of main electrodes based on the arc discharge between the auxiliary electrodes. A similar situation may occur.

(C) Purpose of the Invention The purpose of the present invention is to first generate arc discharge due to high frequency and high voltage between the main electrode and the auxiliary electrode or between the auxiliary electrodes, and then generate arc discharge due to low frequency and low voltage between the main electrodes. An object of the present invention is to provide a metal halide lamp in which arc discharge is reliably induced between main electrodes when a high frequency and high voltage is applied.

(d1) Structure of the Invention The present invention can be summarized as follows: A main discharge path formed between the main electrodes in the above-mentioned metal halide lamp lighting device, and a main electrode.

It is characterized in that the auxiliary electrodes or the auxiliary discharge path formed between a pair of auxiliary electrodes intersect within the tube.

(e) Description of Embodiments FIG. 1 shows a schematic diagram of a saw metal halide lamp lighting device using a metal halide lamp according to an embodiment of the present invention.

In the same figure, the voltage of a commercial power source 1 is applied via a current limiting inductor 2 to terminals PI and P4 of a metal 1-ride lamp 3.
given between. Further, the power source 1 directly drives the high frequency high voltage circuit 4. The output voltage of the high frequency high voltage circuit 4 is applied to the terminals P, 2. P,,,3
It is stamped or added in between.

The above terminal P, 1. P4 is connected to the main electrodes A and A' of the metal halide lamp 3, and terminals P2. P'3 is connected to auxiliary electrodes c, c'. The main electrodes A and A and the auxiliary electrodes c and c' face each other, and the main discharge path formed between the main electrodes A and A' is H? 1till Jt heavy tic
, c'nJrJfJtE,j! Secondary release tL! :
'It intersects almost at the center of IFrM. Also,
The gap of the sub-discharge path is shorter than the gap of the main discharge path1
It is set as follows. Note that the molybdenum foils 30a to 31b provided within the support 30.31 are intended to alleviate strain caused by a difference in thermal stress between the electrode line and the support 30.31.

In the above configuration, when the commercial power supply 1 is turned on, the high frequency circuit 4 operates first, and the terminal P2. A high frequency arc discharge is formed between the auxiliary electrodes c and c' via P3. When a high-frequency arc discharge occurs between the auxiliary electrodes C and C, since the main discharge path and the auxiliary discharge path intersect, the conductivity of the main discharge path increases rapidly due to the arc discharge. As a result, the commercial power supply 1 causes an under-discharge to occur in the main discharge path. In this way, the auxiliary electrode C1C
After a high-frequency arc discharge occurs between the main electrodes A and A', the arc discharge &gi will be generated and a low-frequency arc discharge will be induced between the main electrodes A and A'. The probability of induction is extremely high even though the applied voltage is low frequency and low voltage mains voltage. The reason for this is that the sub-discharge path formed between the auxiliary electrodes C and C'' intersects with the above-mentioned main discharge path, so when arc discharge occurs in the sub-discharge path, the ionized ions This is because the discharge path also suddenly becomes highly excited.

In this manner, by intersecting the main discharge path and the sub-discharge path within the metal halide lamp 3, it is possible to almost certainly obtain arc discharge in the main discharge path induced by arc discharge in the sub-discharge path.

FIG. 2 is a circuit diagram showing a specific example of the above-mentioned high frequency high voltage circuit.

Basically, this embodiment consists of an oscillation booster circuit 5 which obtains a constant high frequency high voltage through an oscillation boosting action, and a step-up circuit which boosts its output voltage using a step amplifier.

The oscillation booster circuit 5 is constructed by connecting a series circuit of a thyristor 51 and a nonlinear inductor 52 in parallel to an oscillation capacitor 50, and inserting an intermittent capacitor 53 between the circuit and the commercial power supply 1. . Also,
The step amplifier circuit consists of a step-up transformer 6 in which the turns ratio of the negative side and the secondary side is set appropriately.

In the above configuration, when the commercial power supply 1 is turned on, the oscillation capacitor 50 is charged via the intermittent capacitor 53, and when the terminal voltage reaches the breakover voltage of the thyristor 51, the thyristor 51 becomes conductive and oscillates. A boost oscillation operation is started by the cooperation between the capacitor 50 and the boost nonlinear inductor 52. This operation occurs at the beginning of each half cycle of the mains voltage due to the action of the intermittent capacitor 53.

Due to the above-described operation at the beginning of the multiplication cycle, a high frequency voltage several times the commercial power supply voltage is intermittently generated in the primary winding i of the step-up transformer 6. The high frequency voltage of step-up transformer 6 is further stepped up according to the turns ratio, and capacitor 7
is applied between auxiliary electrodes c and c' of metal halide lamp 3 via.

The turns ratio of the step-up transformer 6 is set to such an extent that the output voltage of the oscillating step-up circuit 5 is stepped up several times.

The oscillation booster circuit 5 used in this embodiment is one that stops the oscillation operation when the impedance between terminals A and C becomes low impedance. In addition, the capacitor 7 is selected to have a voltage drop that is extremely large when arc current flows. Therefore, if arc discharge occurs between the auxiliary electrodes C3C' due to high frequency and high voltage, the impedance between the auxiliary electrodes will drop rapidly, and the operation of the oscillation booster circuit 5 will stop, and if the oscillation operation does not stop. Even though
The voltage drop across the capacitor 7 corresponds to the auxiliary electrode c,
The arc discharge between c' stops. That is, in this embodiment, arc discharge occurs in the sub-discharge path, and at the same time as it is induced to form an arc discharge in the main discharge path, the arc discharge in the sub-discharge path automatically stops. Arc discharge due to the high frequency ml voltage will no longer occur in the sub-discharge path.

FIG. 3 shows another embodiment of the invention.

In the above embodiment, one pair of main electrodes and one pair of auxiliary electrodes were provided, but the lamp of this embodiment has one auxiliary electrode.
Only one was used.

When using only one auxiliary electrode in this way, an arc discharge with high frequency and high voltage is generated between one of the pair of main electrodes and the auxiliary electrode, and based on the arc discharge, a low frequency wave is generated between the main electrodes. Induces arcing due to low voltage. Therefore, in a metal halide lamp not shown in FIG. 3, terminal P3 of auxiliary electrode C and terminal P of main electrode A are
A high frequency high voltage is applied between the terminals PL and P4, and a low frequency low voltage, that is, a commercial power supply voltage is applied between the terminals PL and P4.

As shown in the figure, the discharge path is formed by overlapping a sub-discharge path between the main discharge path formed between the main electrodes A and A'. That is, the electrode arrangement structure is such that the tip of the auxiliary electrode C is located within the main discharge path. Based on the high-frequency arc discharge in the sub-discharge path, the effect of inducing low-frequency arc discharge in the main discharge path is exactly the same as in the above embodiment, and the main electrode A
Due to the high frequency arc discharge in the sub discharge path between the auxiliary electrodes C, the conductivity of the main discharge path increases rapidly, and the arc discharge between the main electrodes A and A' due to the low frequency and low voltage starts. According to the electrode configuration of this embodiment, since the auxiliary electrode C is located in the main discharge path, the auxiliary electrode C is heated during normal lighting. Therefore, a radiator 8 is provided at the auxiliary electrode C.

FIG. 4 shows a third embodiment of the invention.

The metal halide lamp of this embodiment is similar to the embodiment shown in FIG. 1 in that a pair of opposing main electrodes A, A' and a pair of opposing auxiliary electrodes c, c' are provided as electrodes. Also, what is the main discharge path formed between the main electrodes? ili
The same is true in that the sub-discharge path formed between the auxiliary electrodes intersects within the tube, and the gap of the sub-discharge path is set shorter than the gear of the main discharge path. The difference is that the auxiliary electrode c7c' is fixed to dielectric ceramic tubes 9 and 10 attached to the main electrode. therefore,
There are two electrode terminals, and a high frequency high voltage and a low frequency low voltage (commercial power supply voltage) are applied between the electrodes 2124 in a superimposed manner. The starting oscillation booster circuit 5 and step-up circuit shown in FIG. 5 which are suitable for this metal halide lamp are substantially the same as the circuit shown in FIG. The difference is that an intermittent capacitor 53 is connected in series with a nonlinear inductor 52. Another difference is that the oscillating booster circuit 5 is connected to the commercial power supply 1 via the current limiting inductor 2. Due to these differences, the step-up transformer 6
A voltage in which the commercial power supply voltage and high frequency high voltage are superimposed is generated at the secondary output. That is, a superimposed voltage of a commercial power supply voltage and a high frequency high voltage is applied between the terminals PI and P4 of the metal halide lamp 3 in FIG. 4.

When the above superimposed voltage is applied between the terminals PI and P4, the high frequency high voltage is applied to the auxiliary electrode c via the ceramic tubes 9 and 10.
, c'. Since the gap between the auxiliary electrodes c and c' is shorter than the gap between the main electrodes A and A,
First 1. High frequency arc discharge occurs between the auxiliary electrodes. High-frequency arc discharge rapidly increases the conductivity of the main discharge path that intersects with the sub-discharge path, bringing the main discharge path into a highly excited state.

As a result, low frequency arc discharge occurs also in the main discharge path due to the low frequency and low commercial power supply voltage.

Since the oscillating booster circuit 5 is set to stop oscillation due to a decrease in impedance on its output side, it stops oscillating at the same time as arc discharge occurs in the main discharge path. Further, when arc discharge occurs in the sub-discharge path, a sudden voltage drop occurs due to the capacity of the ceramic cylinder 9.10. Therefore, when a high frequency high voltage is applied between the auxiliary electrodes and a high frequency arc discharge is generated in the auxiliary discharge path, a low frequency arc discharge is immediately generated in the main discharge path, and a high frequency high voltage is generated between the auxiliary electrodes. is no longer applied. Then, a low frequency arc discharge occurs in the C1 main discharge path. Thereafter, the high excitation state in the main discharge path is maintained, so that the low frequency arc discharge is maintained. As described above, according to this embodiment, the metal halide lamp only needs two terminals, and the auxiliary electrode is not shown in FIG. (f) Effect of the invention that can prevent wear and tear on the electrodes As described above, according to the present invention, the main discharge path and the sub-discharge path intersect within the tube, so that high-frequency arc discharge can be prevented in the sub-discharge path. When this occurs, the main discharge path will almost certainly suddenly become highly excited, which has the advantage of preventing arc discharge failure in the main discharge path due to low frequency and low voltage.

[Brief explanation of drawings]

FIG. 1 shows a schematic diagram of a metal halide lamp lighting device using a metal halide lamp according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing a specific example of a high frequency high voltage circuit. FIG. 3 is a schematic diagram of a metal halide lamp according to another embodiment of the present invention. FIG. 4 is a schematic diagram of a metal halide lamp according to still another embodiment of the present invention. FIG. 5 is a circuit diagram of a lighting device for lighting the metal halide lamp shown in FIG. 4. l - commercial power supply, 3 - metal halide lamp, 4 - high frequency high voltage circuit, 5 - high frequency voltage generating circuit, 6 - stiso amplifier circuit, A (A') - main electrode, C (C') - auxiliary electrode. Dismissal Person: ShinNippon Electric Co., Ltd. Agent Patent Attorney Hisao Komori Figure 1, -2 Figure 2 Figure 5 Procedural Amendment 1. Display of the case 1982 Patent Application No. 178597 2 Name of the invention Metal Hawaii Playing Card 3 Person making the amendment Relationship to the case Patent Applicant contact information Shin Nihon 2-9-1 Seiran, Otsu City, Shiga Prefecture 520 Denki Co., Ltd. Patent Department Phone: Otsu (0775) 37-2100 Tokyo Contact information: Tokyo (03) 454-snti (1) Full text of the specification (2) Drawing 6, contents of amendments (1) Attached corrected specification As of. (2) As per the attached corrected drawing. Amendment Name of the Invention High Intensity Discharge Lamp 2, Detailed Description of the Claimed Invention □ (a) Technical field to which the invention relates This invention is used as a high-efficiency white □ light source. The present invention relates to a high-intensity discharge lamp, typically a metal halide lamp, in which scandium, sodium, and water are sealed in an arc tube. (b) Background of the Invention Although metal haphid lamps have the advantage of being a light source with high efficiency and high color rendering properties, they have the disadvantage that restarting is difficult because the internal pressure becomes extremely high after initial startup. In other words, with ordinary metal halide lamps, first a low-pressure glow discharge is generated between the main electrode and the auxiliary electrode, so the starting voltage is low and initial starting is very easy.
When the inside of the arc tube reaches a high temperature and high pressure, the starting voltage reaches more than several 1' OKV with an interelectrode gap of several to several tens of degrees. In view of the early ripening, the applicant placed a pair of main electrodes facing each other in the arc tube, and also set one main electrode and a high-frequency electrode facing each other, and applied a low-frequency voltage between the main electrodes and a high-frequency electrode. First, apply a high voltage and a high wave voltage between the main electrodes.
We have proposed a starting/lighting device for metal halide lamps that generates high-frequency arc discharge between a high-frequency electrode and the main electrode, and based on this generates a low-frequency, low-voltage arc discharge between the main electrodes. According to this metal halide pump starting/lighting device, since a high frequency high voltage is first applied between the main electrode and the high frequency electrode, high frequency arc discharge occurs relatively easily between the two electrodes. The reason for this is that the starting voltage is lowered by the high frequency and that a large amount of energy can be applied to the electrodes per unit time. When this high frequency arc discharge occurs, the conductance between the main electrodes increases rapidly, and low frequency arc discharge is induced between the main electrodes. When a low frequency arc discharge occurs between the main electrodes, the highly excited state is maintained thereafter, so that the arc discharge due to the low frequency and low voltage is maintained between the main electrodes. In this way, since high frequency arc discharge is first generated between the main electrode and the high frequency electrode, there is an advantage that not only starting but also restarting becomes very easy. However, with this method, depending on the type of lamp, the high-frequency glow discharge between the main electrode and the high-frequency electrode may not lead to low-frequency arc discharge due to the low voltage between the main electrodes. (c) Purpose of the Invention The purpose of the present invention is to first develop a method for generating a high frequency signal between a pair of high frequency electrodes. Alternatively, a high-frequency lamp such as a metal lever wide lamp that generates high-frequency arc discharge by high-frequency high voltage between one high-frequency electrode and one main electrode, and then generates arc discharge by low-frequency voltage between the main electrodes. An object of the present invention is to provide a high-intensity discharge lamp in which low-frequency arc discharge is reliably induced between main electrodes when high-frequency and high voltage is applied. (d) Structure of the Invention In summary, the present invention provides the following: In the above-mentioned high-intensity discharge lamp, a low-frequency main discharge path is formed between the main electrodes, and a low-frequency main discharge path is formed between the main electrode, a high-frequency high voltage, or a pair of high-frequency electrodes. The electrodes are arranged so that the high-frequency auxiliary discharge paths intersect within the tube. (e) Description of Embodiments FIG. 1 shows a schematic diagram of a starting and lighting device for a metal halide lamp using a metal halide pump according to an embodiment of the present invention. In the figure, the voltage of a commercial power supply 1 is applied between terminals PI' and P4 of a metal halide lamp 3 via a current limiting inductor 2. Further, the power source 1 directly drives the high frequency high voltage circuit 4. The output voltage of the high frequency high voltage circuit 4 is the terminal P2 of the metal halide lamp 8. It is applied between p+a. The terminals p3 to p4 are connected to the main electrodes A and A' of the meta IL//S seat lamp 3, and the terminals P'2. P3 is connected to high frequency type 4mC, C'. All electrodes A L, A
', and the high frequency electrodes c and c' are facing each other, and the low frequency main discharge path formed between the main electrodes A and "A' is the high frequency auxiliary discharge path formed between the high frequency electrodes C and C/. They intersect at approximately the center of the tube.Also, the gear 1 of the high frequency auxiliary discharge path is set shorter than the gear 1 of the low frequency main discharge path. Electron radioactive material is attached if necessary.Also, molybdenum foils 80a to 81b provided in the support 80.81
is a known means for alleviating the strain caused by the difference in thermal stress between the electrode wire and the support 80.81. In the above configuration, when the commercial power supply 1 is turned on, the high frequency high voltage circuit 4 operates and a high frequency high voltage is applied between the high frequency electric currents tFMc and c' through the terminals P2 and P8. High frequency arc discharge occurs relatively easily due to the reduction in starting voltage and the application of large energy per unit time. High frequency electrode C1C
When a high-frequency arc discharge occurs between . As a result, low frequency arc discharge is generated by the commercial power supply 1 in the low frequency main discharge path. In this way, after a high-frequency arc discharge occurs between the high-frequency electrodes c and c', a low-frequency arc discharge is induced between the main electrodes A' and A' due to the high-frequency arc discharge. The probability of low frequency arc discharge occurring in the low frequency main discharge path of is extremely high regardless of the applied voltage being low frequency and low voltage commercial voltage. The reason for this is that the high-frequency auxiliary discharge path formed between the high-frequency electrodes c and c′ intersects with the low-frequency main discharge path, so when high-frequency arc discharge occurs in the high-frequency auxiliary discharge path, the ionization This is because the low-frequency main discharge path is also suddenly brought into a highly excited state by the ions generated. This is a low-frequency circuit diagram in the main discharge path induced by high-frequency arc discharge in the auxiliary discharge path due to the intersection of the low-frequency main discharge path and the high-frequency auxiliary discharge path in the metal halide lamp 3. Basically, in this embodiment, the oscillating booster circuit 5! obtains a constant high frequency and high voltage by the oscillating boosting action. ! :, and a step-up circuit that boosts its output voltage using a step-up circuit. The oscillating external pressure circuit 5 has the following characteristics for the oscillating capacitor 50:
It is constructed by connecting a series circuit of a thyristor 51 and a nonlinear inductor 52 in parallel, and inserting an intermittent oscillation capacitor 58 between the circuit and the commercial power supply 1. Further, the step, amplifier, and amplifier circuits each include a step-up transformer 6 in which the turns ratio of the negative side and the secondary side is appropriately set. In the above configuration, when the commercial power supply 1 is turned on, the oscillation capacitor 50 is charged via the intermittent oscillation capacitor 58, and when the terminal voltage reaches the breakover voltage of the thyristor 51, the thyristor 51 becomes conductive. A step-up oscillation operation is started by the cooperative action of the oscillation capacitor 50 and the step-up nonlinear inductor 52. This operation is
Due to the action of the intermittent oscillation capacitor 58, this occurs at the beginning of each half cycle of the mains voltage. Due to the above operation at the beginning of the magnification cycle, a large-amplitude current flows through the primary winding of the step-up transformer 6. The external pressure transformer 6 further boosts the induced voltage due to the high frequency current according to the turns ratio, and applies it between the high frequency electrodes c and c' of the metal halide lamp 8 via the capacitor 7. The turns ratio of the step-up transformer 6 is set to such an extent that the output voltage of the oscillating step-up circuit 5 is stepped up several times. As a result, not only a high voltage but also a single voltage with a high frequency is applied between the high frequency electric currents *c and C', and therefore initial starting/restarting is facilitated through high frequency discharge. The oscillation booster circuit 5 used in this embodiment is one that stops oscillation when the impedance between terminals A and C becomes low and the lamp voltage becomes less than the breakover voltage of the thyristor 51. ing. Further, as the capacitor 7, a capacitor whose voltage drop becomes extremely large when a low frequency arc current flows is selected. Therefore, when an arc discharge occurs due to high frequency and high voltage between the high frequency electrodes c and c', the impedance between the high frequency electrodes, and thus between the main electrodes, decreases, so that the operation of the oscillating booster circuit 5 stops, and Even if the oscillation operation does not stop, the voltage drop across the capacitor 7 causes a low frequency voltage between the high frequency electrodes C1C',
discharge stops. That is, in this embodiment, high-frequency arc discharge occurs in the auxiliary discharge path, and induced by it, low-frequency arc discharge is formed in the main discharge path, and at the same time, the high-frequency arc discharge in the auxiliary discharge path is automatically stopped. . Therefore, arc discharge due to high frequency and high voltage will not occur in the auxiliary discharge path from now on. FIG. 8 shows another embodiment of the invention. In the above embodiment, a pair of main electrodes and a pair of high-frequency electrodes were provided, but the lamp of this embodiment uses only one high-frequency electrode. In this case, when only one high-frequency electrode is used, either of the pair of main electrodes generates an arc discharge due to high frequency and high voltage between the other one and the high-frequency electrode, and based on the arc discharge, an arc discharge is generated between the main electrodes. Induces arc discharge due to low frequency and low voltage. Therefore, in the metal halide lamp shown in FIG. 8, a high frequency high voltage is applied between the terminal P8 of the high frequency electric current tFMc and the terminal P1 of the main electrode
, P4, apply a low frequency low voltage, that is, a commercial power supply voltage. As shown in the figure, the auxiliary discharge path is formed by overlapping the main discharge path formed between the main electrodes A and A'. That is, the electrode arrangement structure is such that the tip of the high-frequency FMc is located within the main discharge path. Based on the high-frequency arc discharge in the auxiliary discharge path, the inducing effect of low-frequency arc discharge in the main discharge path is exactly the same as in the above embodiment,
Due to the high-frequency arc discharge in the auxiliary discharge path between the main electrode A and the high-frequency electrode C, the conductance of the main discharge path increases rapidly, and the main electrode A due to the low frequency and low voltage. Low frequency arc discharge starts between A'. In addition, according to the electrode configuration of this embodiment, the high frequency electrode C is always located in the main discharge path, so that the high frequency electrode C is heated during normal lighting. Therefore, a radiator 8 is provided on the high frequency electrode C. FIG. 4 shows an eighth embodiment of the invention. The metal halide lamp of this embodiment is similar to the embodiment shown in FIG. 1 in that a pair of opposing main electrodes A, A' and a pair of opposing high frequency electrodes C9C' are provided as electrodes. In addition, the main discharge path formed between the main electrodes and the auxiliary discharge path formed between the high-frequency electrodes intersect within the arc tube, and the gap of the auxiliary discharge path is set shorter than the gap of the main discharge path. But it's the same. The difference is that the high frequency electrode c, 'c' is the main electrode,
Attached high-frequency path dielectric 1, for example, a ceramic tube 9.
This is fixed at 10. Therefore, the electrode terminal is 2
This electric fMP1. It will be applied in a superimposed manner during P4. FIG. 5 shows an example of a starting circuit suitable for this metal halide lamp. The oscillating external pressure circuit 5 and the step-up circuit are substantially the same as the circuit shown in FIG. Intermittent oscillation capacitor 5
The difference is that 3 is connected in series with a nonlinear inductor 52. Another difference is that the oscillation booster circuit 5 is connected to the commercial power source l via the current limiting inductor 2. Due to such a difference, a voltage in which the commercial power supply voltage and the high frequency high voltage are superimposed is generated at the secondary output of the step-up transformer 6. That is, the superimposed voltage of the commercial power supply voltage and the high frequency voltage is applied between the terminals p i'' and pa of the metal halide lamp 8 in FIG. 4. The above voltage is applied between the terminals Pi and P'4. When the superimposed voltage force ξ is applied, the high frequency high voltage is applied between the high frequency electrodes c and c' through the ceramic cylinder 9.10.The gear knob between the high frequency electrodes c and c' is connected to the main electrode A, Since the gear between A and A' is shorter than the knob, high-frequency arc discharge first occurs between the high-frequency electrodes.High-frequency arc discharge rapidly increases the conductance of the main discharge path that intersects with the auxiliary discharge path, and the main discharge path As a result, low-frequency arc discharge occurs during the main discharge due to the low-frequency and low-voltage commercial power supply voltage.Such an operation occurs at the first start.The second restart is almost the same. Since the oscillation booster circuit 6 is set to stop oscillation due to a decrease in the impedance on its output side, it stops oscillation at the same time as low-frequency arc discharge occurs in the main discharge path. When low-frequency arc discharge occurs in the path, a sudden voltage drop occurs due to the capacitance of the ceramic tube 9.10.Therefore, a high-frequency high voltage is applied between the high-frequency electrodes, and high-frequency arc discharge occurs in the auxiliary discharge path. When this occurs, low-frequency arc discharge immediately occurs in the main discharge path, and high-frequency high voltage is no longer applied between the high-frequency electrodes.And when low-frequency arc discharge occurs in the main discharge path, from then on, low-frequency arc discharge occurs in the main discharge path. A low-frequency arc discharge is maintained because the highly excited state of Unlike a lamp, a part of the high-frequency electrode is not located in the main discharge path, so wear and tear on the high-frequency electrode can be prevented. Since each electrode is arranged so that the high-frequency arc discharge path intersects within the tube, when high-frequency arc discharge occurs in the auxiliary discharge path, the main discharge path is rapidly and reliably brought into a highly excited state, not only during initial startup but also during restart. It has the advantage of ensuring that low frequency arc discharge occurs in the main discharge path due to low frequency and low voltage during startup, or that the time required for low frequency arc discharge to occur can be significantly shortened. Brief explanation of drawings Figure 1 1 shows a schematic configuration diagram of a metal haphid lamp starting/lighting device using a metal haphid lamp according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing a specific example of a high frequency high voltage circuit. FIG. 3 is a schematic diagram of a metal halide lamp according to another embodiment of the present invention. FIG. 4 is a schematic diagram of a metal halide lamp according to still another embodiment of the present invention. FIG. 5 is a circuit diagram of a starting/lighting device for starting and lighting the metal halide lamp shown in FIG. 4. 1...Commercial source, 3...Metal halide lamp, 4...High frequency high voltage circuit, 5...
...High frequency/voltage generation circuit, 6...
・Stethopoa tube circuit, c (c')...High frequency electrode. Figure 1 Figure ts2 Figure 4 Figure 5

Claims (1)

[Claims] Tl) forming a main discharge path between a pair of main electrodes, and between a pair of auxiliary electrodes or with either one of the half electrodes;
Using a metal halide lamp that forms an auxiliary discharge path between two auxiliary electrodes, high frequency and high voltage are applied between a pair of Φ auxiliary electrodes or between the main electrode and the auxiliary electrode to generate a starting arc discharge. A metal halide lamp lighting device, wherein the main discharge path and the sub discharge path intersect within the tube.