JP2002324518A - Metal halide lamp, metal halide lamp lighting device, and automotive headlight device - Google Patents

Abstract

(57) [Problem] To provide a mercury-free metal halide lamp, a metal halide lamp lighting device, and a headlight device for a vehicle, which can shorten a red light emission time at the time of starting. SOLUTION: A metal halide lamp 1 includes a discharge space 2.
a, and a discharge vessel 2 having sealing portions 2b provided at both ends of the discharge space 2a, and a protruding portion projecting into the discharge space 2a, disposed so as to face from the sealing portion 2b to the discharge space 2a. 3c having a pair of electrodes 3.
When the metal halide lamp 1 is turned on for 50 hours or more, when the lamp is turned off, 0.005 mg or more of the protruding portion 3c and 60% by weight or more of the total weight of the free halogen 7 present in the discharge vessel 2 are emitted. Halogen 7 is attached.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal halide lamp, a metal halide lamp lighting device using the same, and a vehicle headlight device.

[0002]

2. Description of the Related Art Metal halide lamps have improved luminous efficiency and color rendering properties by encapsulating various metal halides (metal halides) together with mercury and a rare gas in an arc tube. As described above, metal halide lamps have characteristics such as high efficiency and high color rendering properties, and are therefore widely used for general lighting such as store lighting and road lighting. Further, metal halide lamps have been used as light sources in headlight devices of automobiles.

As described above, conventional metal halide lamps generally use mercury as a part of the discharge medium. However, as environmental problems are becoming more serious, it is necessary to reduce the use of mercury, which has a large environmental impact in the field of lighting, and it is very important to eliminate mercury from all lamps. Is considered as.

With respect to such a problem, several measures have been proposed for preventing the use of mercury even in metal halide lamps. For example, Japanese Patent No. 2982198 and JP-A-6-84496 describe a metal halide lamp in which a halide such as scandium (Sc), sodium (Na), or a rare earth element and a rare gas are sealed as a discharge medium. .

Japanese Patent Application Laid-Open No. H11-238488 discloses a metal halide lamp in which a second halide having a high vapor pressure and hardly emitting light is enclosed in addition to a first halide which is a main luminescent substance. . Further, Japanese Unexamined Patent Application Publication No.
JP-A-307048 discloses a metal halide lamp in which a halide of yttrium (Y) or indium (In) is sealed as a third additive in addition to a halide of Sc and Na. These all address various problems based on not using mercury (Hg).

[0006]

In the above-mentioned metal halide lamp not using mercury (mercury-free metal halide lamp), based on the fact that mercury is not used as a part of the discharge medium, the following is newly added. There is a problem.

That is, when the metal halide lamp is turned on to some extent, a part of the metal halide is decomposed to generate free halogen. In a metal halide lamp using mercury, the generated free iodine reacts with mercury to form mercury iodide, etc., so it is almost not present in the arc tube, but in a mercury-less metal halide lamp, mercury is substantially absent. Free halogen is present in the arc tube. Such free halogens are colored in the gaseous state. Specifically, the free iodine in the gaseous state is purplish red. Therefore,
When free iodine exists in a gaseous state in the arc tube, the metal halide lamp emits reddish purple light. In addition,
Since this free iodine is decomposed by the discharge, reddish purple light emission disappears with this decomposition. By the way, on traffic,
A reddish color such as magenta is a color indicating danger. Therefore, when a mercury-free metal halide lamp is used as a headlight light source of an automobile, it is preferable that the red light emission time be short. However, there is a problem that a red light emission time is long at the time of starting the metal halide lamp.

[0008] For example, when a metal halide lamp is used as a headlight light source of an automobile, a quick rise of a light beam is required due to safety problems. In a metal halide lamp using mercury, the startup of the luminous flux is accelerated by applying electric power at the time of starting which is twice or more of the emission of the mercury and the stability. However, the mercury-free metal halide lamp has a problem that since mercury is substantially absent, there is no emission of mercury and the light flux rises slowly.

The present invention has been made to solve the above-mentioned conventional problems. That is, it is an object of the present invention to provide a mercury-free metal halide lamp, a metal halide lamp lighting device, and a headlight device for a vehicle, which can shorten the red light emission time at the time of starting. It is another object of the present invention to provide a mercury-free metal halide lamp, a metal halide lamp lighting device, and a headlight device for an automobile, which can accelerate the rise of a light flux.

[0010]

According to a first aspect of the present invention, there is provided a metal halide lamp comprising: a discharge vessel having a discharge space; and sealing portions provided at both ends of the discharge space; A pair of electrodes each having a protrusion protruding into the discharge space, and a metal foil hermetically sealed to each of the sealing portions and joined to each of the electrodes; External leads joined to the respective metal foils and led out of the discharge vessel;
A discharge medium sealed in the discharge vessel and containing a metal halide and a rare gas and containing essentially no mercury, wherein the metal halide lamp is turned on for 50 hours or more. Sometimes, 0.005 mg or more of the protruding portion and 60% by weight based on the total weight of the solid free halogen present in the discharge vessel.
The above-mentioned solid free halogen is attached.

In the invention described in claim 1 and each of the inventions described below, the definitions and technical meanings of terms are as follows unless otherwise specified.

(Discharge Vessel) The discharge vessel is made of a fire-resistant and light-transmitting airtight container, and has a discharge space and sealing portions provided at both ends thereof. The airtight container is
The discharge lamp may be made of any material as long as it has fire resistance enough to withstand the normal operating temperature of the discharge lamp and can emit visible light of a desired wavelength range generated by the discharge to the outside. For example, quartz glass, translucent alumina, Y
Ceramics such as AG or single crystals thereof can be used. If necessary, a halogen-resistant or metal-resistant transparent film may be formed on the inner surface of the hermetic container, or the inner surface of the hermetic container may be modified.

(Regarding the Electrodes) A pair of electrodes are provided so as to face each other from the sealing portion to the discharge space.
It has a projection projecting into the discharge space. The metal halide lamp of the present invention may be configured to be lit by either AC or DC. When operated by an alternating current, the pair of electrodes can have the same structure.

The projecting portion is a portion of the electrode exposed in the discharge vessel. The length of the protruding portion is referred to as a discharge protruding length.

When the metal halide lamp of the present invention is used for a headlight of an automobile, it is advantageous to make the diameter of the tip of the projection larger than the diameter of the root. In other words, the number of times the lamp blinks in an automobile headlight becomes extremely large, and a larger current flows at start-up than in a steady state. Correspondence can be made, and the occurrence of cracks in the sealing portion can be suppressed by reducing the diameter of the portion sealed by the sealing portion of the electrode. Further, in the case of operating with a direct current, since the temperature of the anode generally rises sharply, it is similarly preferable to increase the diameter of the tip of the anode to increase the heat radiation area. It is not always necessary to increase the diameter of the tip of the cathode.

The distance between the pair of electrodes is practically 5
mm or less is suitable. That is, the distance between the electrodes is 5 mm
If it exceeds, it will be far from the point light source, and the focus characteristic of the optical system will be poor. For example, when it is used as a light source for a vehicle headlight, the brightness of the irradiation surface will be reduced. The distance between electrodes referred to here corresponds to a short arc type metal halide lamp. However, the present invention is not necessarily limited to this, and a long arc type metal halide lamp can be configured. .

(Metal Foil) The metal foil is hermetically sealed in each sealing portion and is joined to each electrode. It is also connected to external leads.

As the metal foil, for example, a molybdenum foil can be used. The metal foil is preferably formed in a strip shape having a thickness of, for example, 10 to 50 μm. The joining of the metal foil to the electrodes and the external leads is not particularly limited, and may be welding joining or brazing.

(Discharge Medium) The discharge medium is sealed in a discharge vessel and contains a metal halide and a rare gas. As the metal halide, various metal element halides can be used. For example, a metal halide (first halide) mainly contributing to light emission is used. As such a halide, a halide of one or more metal elements selected from sodium (Na), scandium (Sc) and rare earth elements can be used. Na and Sc are particularly highly efficient luminescent substances.

The metal halide is one or a plurality of metal halides (second halides) having a relatively high vapor pressure and less likely to emit light in the visible light region than the metal of the first halide. ) Can be included. The metal which does not easily emit light in the visible light region may be any metal as long as it has a higher energy level than the metal of the first halide and the metal of the first halide mainly emits light. By adding such a second halide, it is possible to obtain a lamp voltage close to that of a lamp containing Hg, so that it is possible to improve the electric characteristics and luminous characteristics of the mercury-less metal halide lamp. The second halide also contributes to chromaticity improvement and the like.

Examples of the second halide include magnesium (Mg), iron (Fe), cobalt (Co), chromium (Cr), zinc (Zn), nickel (Ni), manganese (Mn), and aluminum (Al). ), Antimony (S
b), beryllium (Be), rhenium (Re), gallium (Ga), titanium (Ti), zirconium (Zr) and hafnium (Hf) are used.

Further, the metal halide may include a halide (third halide) of one or more metal elements selected from indium (In), tin (Sn), and cesium (Cs). Good. The halide of In contributes to the improvement of emission chromaticity and the like. The halide of Cs is added as a component for correcting the distribution of the arc temperature and reducing the heat loss.

As the metal halide in the present invention,
A metal halide obtained by mixing the above-mentioned first halide with the second halide and further with the third halide is exemplified, but is not necessarily limited thereto. May be one or more metal halides. In addition, some of the two or more metal halides may form a complex halide.

As the halogen constituting the metal halide, any of iodine (I), bromine (Br), chlorine (Cl) and fluorine (F) may be used. Among them, iodine (I) is most preferable. Further, different halogen compounds such as iodide and bromide can be used in combination. The gaseous state of iodine is reddish purple and the gaseous state of bromine is reddish brown.

With respect to the amount of metal halide to be enclosed, for example, the first halide mainly contributing to light emission is 5 to 11 per cc of the inner volume of the discharge vessel (volume of the discharge space).
It can be enclosed in a range of 0 mg. A more preferred range is 5 to 35 mg per cc of the internal volume of the discharge vessel. In such a range, the rise of the light beam can be made faster and the light color can be stabilized. The second halide can be sealed in a range of 0.05 to 200 mg per 1 cc of the inner volume of the discharge vessel. Other halides are appropriately adjusted.

The rare gas acts as a starting gas and as a buffer gas, and acts so as to emit main light immediately after the starting. Generally, the rare gas is not particularly limited as long as it does not pass through the airtight container. Ne) easily permeates quartz glass, so when forming an airtight container with quartz glass,
Argon (Ar), krypton (Kr) or xenon (Xe) is recommended. When light emission immediately after starting depends on a rare gas, xenon is optimal because xenon has the highest light emission efficiency.

When the pressure of the rare gas is increased, the lamp voltage of the metal halide lamp is increased, the lamp input is increased for the same lamp current, and the rising characteristics of the luminous flux can be improved. Good luminous flux rising characteristics are advantageous for any purpose of use, but they are extremely important especially in automotive headlamp devices and liquid crystal projectors. The rare gas is sealed at a pressure of, for example, 3.0 × 10 ⁵ Pa (3 atm) or more, and particularly, 5.1 × 10 ^{5 to} 1.5 × 10 ⁶ Pa (5.0 atm).
To 15 atm).

The metal halide lamp of the present invention is essentially free of mercury. Here, “essentially no mercury is enclosed” is not limited to a state in which no mercury is enclosed, but less than 2 mg of mercury, preferably less than 1 mg of mercury per 1 cc of the inner volume of the discharge vessel. Means to allow the presence of But,
It is environmentally desirable not to encapsulate any mercury. If the electric characteristics of the discharge lamp are maintained by mercury vapor as in the prior art, the short arc type is because 20 to 40 mg of mercury is enclosed per 1 cc of the inner volume of the discharge vessel, and in some cases, 50 mg or more of mercury is sealed. If
In the present invention, the amount of mercury can be said to be essentially small.

(Regarding free halogen) 0.005 mg of solid free halogen of the present invention is applied to the protruding portion of the electrode when the metal halide lamp is turned on for 50 hours or more.
At least 60% by weight based on the total weight of the solid free halogen present in the discharge vessel.

The free halogen is a halogen that is released when the above-mentioned metal halide is decomposed. Further, the halogen constituting the free halogen may be any one kind or plural kinds. That is, when two or more metal halides having different halogens are used, different halogens may be released, and all of these released halogens are referred to as free halogens.

Hereinafter, unless otherwise specified, "free halogen" refers to "solid free halogen".

In addition, free halogen is added to the protruding portion of the electrode at 0.1 mm.
005 mg or more means that the total amount of free halogen adhering to each projection of the pair of electrodes is 0.005 m
g or more. Preferably, 0.05 mg or more of free halogen is attached to the protruding portion of the electrode.

Similarly, the phrase that free halogen adheres to the projecting portion of the electrode at 60% by weight or more based on the total weight of free halogen present in the discharge vessel means that the projecting portion of the pair of electrodes adheres to the projecting portion. This means that the total amount of free halogens present is at least 60% by weight based on the total weight of free halogens present in the discharge vessel. Note that free halogens present in portions other than the protruding portions of the electrodes mainly adhere to the inner wall surface of the discharge vessel.

In order to make free halogen adhere to the protruding portion of the electrode when the metal halide lamp is turned off with the above weight and the above ratio, for example, the temperature of the protruding portion at the time of turning off the metal halide lamp is lower than the temperature of the discharge vessel. To control.
This is because free halogen tends to adhere to the lower temperature.
Specifically, for example, such temperature control is possible by reducing the inner diameter of the discharge vessel. That is, since the discharge vessel is usually formed of a material that is less likely to dissipate heat than the protrusion, the inner diameter of the discharge vessel is reduced, and the temperature of the discharge vessel at the time of lighting is increased by increasing the temperature of the discharge vessel at the time of lighting. Can be lower than the temperature of the discharge vessel. Also, by increasing the thickness of the discharge vessel,
Such temperature control becomes possible. That is, since the discharge vessel is usually made of a material that is less likely to dissipate heat than the protrusion,
By increasing the thickness of the discharge vessel and making it more difficult to dissipate heat, the temperature of the protruding portion when the light is turned off can be lower than the temperature of the discharge vessel.

In the metal halide lamp of the present invention, 50
When the metal halide lamp that has been lit for more than an hour
Since the free halogen is attached to the protruding portion in an amount of 0.005 mg or more and 60% by weight or more based on the total weight of the free halogen present in the discharge vessel, the red light emission time at the time of starting is reduced. be able to. here,
The term “red” includes magenta and reddish brown.

A metal halide lamp according to a second aspect of the present invention is the metal halide lamp according to the first aspect,
The free halogen adhering to the protruding portion is adhering to the tip half of the protruding portion in an amount of 70% by weight or more based on the total weight of the free halogen present in the discharge vessel. .

In order to cause free halogen to adhere to the tip half of the protruding portion when the metal halide lamp is turned off at the above ratio or more, for example, the temperature of the tip half of the protruding portion when the metal halide lamp is turned off is reduced to the temperature of the base half. Control to lower. Specifically, for example, such a temperature control can be performed by making the diameter of the tip portion of the protruding portion larger than the diameter of the root portion. That is, by making the diameter of the tip part larger than the diameter of the root part, the heat radiation area of the tip part increases. As a result, since the heat is more easily dissipated at the distal end than at the root, the temperature at the distal end half of the protrusion at the time of turning off the light can be made lower than the temperature at the root half.

In the metal halide lamp according to the second aspect of the invention, the free halogen adhering to the protruding portion is reduced to a total weight of the total free halogen present in the discharge vessel at a tip half of the protruding portion. On the other hand, since 70% by weight or more is attached, the red light emission time at the time of starting can be further reduced. Further, the rise of the light beam can be hastened.

According to a third aspect of the present invention, there is provided the metal halide lamp according to the first or second aspect, wherein the free halogen is at least one of iodine and bromine. The metal halide lamp according to the third aspect of the present invention defines a configuration of free halogen that can provide a particularly effective effect.

A metal halide lamp according to a fourth aspect of the present invention is the metal halide lamp according to any one of the first to third aspects, wherein the metal halide is at least one selected from the group consisting of sodium, scandium and a rare earth element. Metal halide and magnesium,
Iron, cobalt, chromium, zinc, nickel, manganese, aluminum, antimony, beryllium, rhenium, gallium, titanium, zirconium, hafnium, indium, tin and cesium, and at least one metal halide. I do. Claim 4
The metal halide lamp of the described invention is one in which usable halide is specified.

According to a fifth aspect of the present invention, there is provided the metal halide lamp according to any one of the first to fourth aspects, wherein the metal halide lamp operates with a lamp power of 20 to 60 W at a stable time. A small metal halide lamp having a lamp power of 20 to 60 applied to the lamp is suitable as a light source for a headlight device for an automobile. More preferably, the lamp power at the time of stabilization is 20 to 50 W. Further, the maximum current at the time of starting the metal halide lamp is preferably 3 A or more, and such a metal halide lamp is suitable as a light source of a headlight device for an automobile.

According to a sixth aspect of the present invention, there is provided a metal halide lamp lighting device comprising: the metal halide lamp according to any one of the first to fifth aspects; and a lighting circuit for lighting the metal halide lamp with direct current. Features metal halide lamp lighting device. According to a sixth aspect of the present invention, there is provided a metal halide lamp lighting device that performs direct current lighting of the metal halide lamp of the present invention.

That is, by lighting the metal halide lamp of the present invention by direct current, the size of the apparatus can be reduced as compared with the case where the Hg-filled metal halide lamp is lighted by alternating current. This is because direct current is used in automobiles and there is no need to convert power to alternating current. Furthermore, in the case of DC lighting, the temperature of the anode rises sharply, and the amount of evaporation of the luminescent substance on the anode side increases, so that abnormal light emission easily occurs. According to the present invention, such abnormal light emission caused by DC lighting can be reliably eliminated. As described above, the metal halide lamp lighting device of the present invention is particularly suitable for a headlight device of an automobile.

According to a seventh aspect of the present invention, there is provided an automotive headlamp apparatus according to any one of the first to fifth aspects, wherein the metal halide lamp and the metal halide lamp are disposed, and the longitudinal direction of the discharge vessel of the metal halide lamp. And a vehicle headlight device main body having an optical axis along a direction.

Since the headlight device for an automobile of the present invention includes the metal halide lamp of the present invention, the red light emission time at the time of starting can be shortened, and safety can be improved. In addition, the vehicle headlight device main body includes all the remaining components excluding the metal halide lamp from the vehicle headlight device.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, a metal halide lamp according to a first embodiment of the present invention will be described. FIG. 1 is a sectional view showing a schematic configuration of the metal halide lamp according to the present embodiment. In these figures, 1 is a metal halide lamp, 2 is a discharge vessel,
Reference numeral 3 denotes an electrode, 4 denotes a metal foil, 5 denotes an external lead, and 6 denotes a metal halide.

The metal halide lamp 1 has a tipless discharge vessel 2 made of a hollow spindle-shaped quartz glass airtight vessel. An elongated discharge space 2a is formed inside the discharge vessel 2, and a pair of sealing portions 2b are provided integrally at both ends of the discharge vessel 2, respectively. In the drawing, 2c indicates the inner wall surface of the discharge vessel 2. The inner diameter of the discharge vessel 2 of the present embodiment is smaller than the inner diameter of the conventional discharge vessel.

In the discharge vessel 2, a metal halide 6 consisting essentially of two or more metal halides is used as a discharge medium.
And a rare gas are enclosed. The discharge medium is essentially Hg
Is not included. Specifically, the metal halide 6 is, for example, one or a plurality of first halides selected from Na, Sc, and rare earth metals contributing to light emission, and the second and third halides described above. It is mainly composed of

A metal foil 4 such as a molybdenum foil is provided in each sealing portion 2a of the discharge vessel 2. This metal foil 4
Is connected to one end of each of the external leads 5. The other ends of the external leads 5 are led out of the discharge vessel 2. The other end of the metal foil 4 is joined to an end of an electrode shaft 3 a of the electrode 3, which will be described later. The electrode 3, the metal foil 4, and the external lead 5 are hermetically sealed by the sealing portion 2b in a state of being joined as described above. By this sealing, the inside of the discharge vessel 2 can be made airtight.

In the discharge space 2a, a pair of electrodes 3 are disposed so as to face each other.
And a tip portion 3b having a diameter larger than that. The distal end portion 3b has a spherical structure, and is formed integrally with the electrode shaft 3a. The diameter of the tip 3b is larger than the diameter of the conventional tip, and the diameter of the electrode shaft 3a is the same as the diameter of the conventional electrode shaft. By designing the discharge vessel 2 and the electrode 3 of the metal halide lamp 1 in this way, it is possible to cause the free halogen 7 to be attached to the electrode 3 in a weight or more and a proportion or more, which will be described later.

The electrode shaft 3a of the electrode 3 is partially embedded in the sealing portion 2b as described above. With this burial,
The electrode 3 is supported at a predetermined position in the discharge space 2a. Here, in the present embodiment, a portion of the electrode 3 that is not sealed to the sealing portion 2b, that is, a portion of the electrode 3 that is exposed in the discharge vessel 2 is referred to as a protrusion 3c. Specifically, for example, the protruding portion 3c includes a portion of the electrode shaft 3a that is not sealed to the sealing portion 2b and a tip portion 3b.

Next, a description will be given of a state when the metal halide lamp 1 according to the present embodiment is turned off when the metal halide lamp 1 is turned on for 50 hours or more. FIG. 2 is a state diagram near the electrodes when the metal halide lamp according to the present embodiment is turned off for 50 hours or more. Free halogens 7 adhere to the protruding portion 3c of the electrode 3 and the inner wall surface 2c of the discharge vessel 2. The free halogen 7 is a halogen released from the metal halide 6 by the decomposition of the metal halide 6.

Specifically, the protrusion 3c of the electrode 3 is set to 0.0
The amount of free halogen 7 which is not less than 05 mg and 60% by weight or more based on the total weight of free halogen 7 existing in the discharge vessel 2
Is attached. More specifically, 70% by weight or more of the free halogen 7 adheres to the tip half 3d of the protrusion 3c with respect to the total weight of the free halogen 7 present in the discharge vessel 2.

In this embodiment, when the metal halide lamp 1 has been turned on for 50 hours or more, the protrusion 3c of the electrode 3 has a weight of 0.005 mg or more and the total weight of free halogen 7 existing in the discharge vessel 2. On the other hand, 60% by weight or more of the free halogen 7 is attached, so that the red light emission time at the time of starting can be reduced.

That is, when the metal halide lamp 1 is turned on, the temperature of the protruding portion 3c of the electrode 3 rises fastest, so that the temperature of the protruding portion 3c of the electrode 3 becomes highest at the time of starting. Here, in the present embodiment, most of the free halogens 7 adhere to the protruding portions 3 c of the electrode 3. Therefore, the rate of evaporation of the free halogen 7 at the start is higher than when most of the free halogen is attached to the discharge vessel, so that the amount of the free halogen 7 that evaporates at the same time is larger than when the free halogen 7 is attached to the discharge vessel. Become. Since the evaporated free halogen 7 is of a red color, light emission during the presence of the evaporated free halogen is of a red color. Further, the evaporated free halogen 7 is decomposed by collision of electrons or rare gas. Here, since a large amount of electrons or rare gas is present in the discharge space 2a, the evaporated free halogens 7 can be simultaneously decomposed. Therefore, the amount of the free halogen 7 that is decomposed at the same time is larger than that when the free halogen 7 is attached to the discharge vessel. As a result, the time from evaporation to decomposition of the free halogen 7 as a whole can be shortened, and the emission time of the red system at the time of starting can be shortened.

Further, in the present embodiment, 70% by weight or more of the free halogen 7 adheres to the tip half 3d of the protruding portion 3c of the electrode 3 with respect to the total free halogen 7 existing in the discharge vessel 2. As a result, the rise of the luminous flux can be hastened.

That is, since most of the free halogen 7 adheres to the tip side half 3d of the protrusion 3c, when most of the free halogen 7 evaporates at the time of starting, the evaporated free halogen 7 is removed from the protrusion 3c. Surrounds the periphery of the tip side half 3d. Here, since free halogen 7 has a high electron adsorption property,
Discharge occurring between the tip side halves 3d, specifically between the tip portions 3b, is hindered. Therefore, the discharge moves from the tip 3b to the base half of the protruding portion 3c where discharge is more likely to occur, and the discharge occurs in half the base. The temperature of the metal halide 6 adhering to the discharge vessel 2 near the base of the protruding portion 3c rises due to the discharge occurring in the base side half-minute, so-called back arc, so that the time until the metal halide 6 emits light is emitted. Can be hastened. Therefore, the rise of the light beam can be hastened. If the evaporated free halogen 7 surrounding the tip half of the protrusion 3 is decomposed by the discharge, the discharge returns to the discharge between the tip 3b from the back arc.

Further, the lamp life can be prolonged by accelerating the rise of the light flux. That is, as described above, at the time of starting, for example, power that is twice or more than that at the time of stable operation is supplied, but the power supply time at the time of starting can be shortened by accelerating the rise of the luminous flux. As a result, deterioration of the sealing portion 2b and the electrode 3 due to a large amount of power input can be prevented, and the lamp life can be extended.

Embodiment 1 Hereinafter, Embodiment 1 will be described. In this example, the emission time of red-violet light at the time of starting was measured using the metal halide lamp 1 according to the first embodiment.

Hereinafter, the metal halide lamp of this embodiment will be described. Note that the metal halide lamp described below is in a state where the lamp is turned on for 50 hours or more.
The discharge vessel of the metal halide lamp of the present embodiment has an inner diameter of 2.6 mm and an average thickness of 2.0 to 2.3 mm. Xenon as a rare gas was 8.6 in the discharge vessel.
It is sealed at a pressure of × 10 ^{5 to} 1.0 × 10 ⁶ Pa (8.5 to 10 atm). In the discharge vessel, only metal iodide is sealed as a metal halide. The electrode protrusion length, which is the length of the protrusion, is set to 1.8 mm. The diameter of the tip of the electrode is 0.7 mm, and the diameter of the electrode shaft is 0.4 mm. 0.005m on the protruding part of the electrode
g or more and 60% by weight or more of free iodine based on the total weight of free iodine present in the discharge vessel.

The metal halide lamp as described above was turned on, and the emission time of reddish purple at the time of starting was measured.
Here, in order to compare with the metal halide lamp according to the present embodiment, as a comparative example, the emission time of red-violet light at the time of starting was also measured for a conventional metal halide lamp.

Hereinafter, a metal halide lamp of a comparative example will be described.
Will be described. Metal halide lamp according to this comparative example
Is a mercury-free metal halide lamp. Also,
The metal halide lamp described in the above is lit for more than 50 hours
It is in the state where it was made. Comparative metal halide run
The discharge vessel has an inner diameter of 4 mm and an average thickness of 1.
0 mm. Xenon as a rare gas is contained in the discharge vessel.
1.1 × 10 ⁶~ 1.3 × 10⁶Pa (11 to 13
Pressure). In addition, halo
Only metal iodide is encapsulated as the metal iodide. Electric
The pole protrusion length is set to 1.2 mm. Also, the electrode
The diameter of the tip is 0.5 mm and the diameter of the electrode shaft is 0.4 m
m. In addition, most of the free iodine is
It adheres to the inner wall.

The measurement results are shown below. The red-violet emission time of the metal halide lamp according to the present embodiment is 0.1 to
The red-violet emission time of the metal halide lamp according to the comparative example was about 1 second, compared to about 0.3 seconds.
Accordingly, it was confirmed that the metal halide lamp according to the present example has a shorter magenta emission time than the metal halide lamp according to the comparative example.

(Embodiment 2) Embodiment 2 will be described below. In this example, the speed of rising of the light beam was measured using the metal halide lamp 1 according to the first embodiment.

In this embodiment, a metal halide lamp similar to the metal halide lamp described in the first embodiment was used.

The metal halide lamp as described above was turned on to measure the speed at which the luminous flux rose. Here, for comparison with the metal halide lamp according to the present embodiment,
For the metal halide lamp using conventional mercury as Comparative Example 1, and for the metal halide lamp of Comparative Example described in Example 1 as Comparative Example 2, the light beam rising speed was also measured.

The measurement results are shown below. FIG. 3 is a graph showing the rising characteristics of the metal halide lamp according to the present embodiment. As shown in FIG. 3, the metal halide lamp according to the present embodiment and the metal halide lamp according to Comparative Example 1 have a luminous flux rising rate of about 1 in about 6 seconds after the power is turned on.
On the other hand, in the metal halide lamp according to Comparative Example 2, the luminous flux rising rate reached about 100% in about 10 seconds after the power was turned on. Therefore, it was confirmed that the metal halide lamp according to the present example had a faster light flux rise than the metal halide lamp according to Comparative Example 2.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described.
An embodiment will be described. In the following description, among the embodiments after this embodiment, description of contents which are the same as those of the preceding embodiment will be omitted. FIG. 4 is a front view showing a schematic configuration of the metal halide lamp according to the present embodiment. This embodiment shows a structure suitable for mounting a metal halide lamp 1 having a configuration similar to that of FIG. 1 to a headlight device for an automobile. In the figure, 11 is an outer tube, 12 is a base, and 13 is an insulating tube.

The outer tube 11 has a function of cutting off ultraviolet rays, and houses therein the metal halide lamp 1 having the same structure as that of FIG. Both ends of the outer tube 11 are respectively fixed to the sealing portions 2b of the metal halide lamp 1, but the inside is not airtight but communicates with the outside air. One sealing portion 2 b of the metal halide lamp 1 is planted on the base 12. The external lead 5 derived from the other end is
It is arranged in parallel with the outer tube 11, and the tip is introduced into the base 12 and connected to a terminal (not shown). The periphery of the external lead 5 is covered with an insulating tube 13.

The direction of light irradiation by the metal halide lamp 1 is the direction opposite to the insulating tube 13. On this occasion,
It is also effective to form the insulating tube 13 with a ceramic tube and color the ceramic tube with black or the like. According to the black ceramic tube, since the light from the metal halide lamp 1 is hardly reflected, glare due to irregular reflection of light can be suppressed. Glare suppression is particularly effective for automotive headlamp devices. The blackening of the ceramic tube can be performed by applying a metal oxide, baking, or the like.

(Third Embodiment) Hereinafter, a third embodiment of the present invention will be described.
An embodiment will be described. FIG. 5 is a perspective view showing a schematic configuration of the vehicle headlight device according to the present embodiment. In the figure, 14 is a reflecting mirror and 15 is a front cover. The reflecting mirror 14 is formed on a deformed paraboloid of revolution by molding plastics, and is configured to attach and detach a metal halide lamp (not shown) shown in FIG. 4 from the top rear surface. The front cover 15 is integrally formed with a prism or a lens by molding a transparent plastic, and is hermetically attached to the front opening of the reflecting mirror 14.

(Fourth Embodiment) Hereinafter, a fourth embodiment of the present invention will be described.
An embodiment will be described. FIG. 6 is a diagram schematically showing a circuit of the metal halide lamp lighting device according to the present embodiment. In this embodiment, a metal halide lamp is configured to perform DC lighting. In the figure, 21 is a DC power supply, 22 is a chopper, 23 is control means, 24 is lamp current detecting means, 25 is lamp voltage detecting means, 26 is starting means, and 27 is a metal halide lamp.

As the DC power supply 21, a battery or a rectified DC power supply is used. In the case of an automobile, a battery is generally used. However, a rectified DC power supply that rectifies AC may be used. If necessary, the electrolytic capacitor 21a is connected in parallel to perform smoothing.

The chopper 22 converts the DC voltage to a required voltage and controls the metal halide lamp 27 as required. When the DC power supply voltage is low, a step-up chopper is used, and when it is high, a step-down chopper is used.

The control means 23 controls the chopper 22. For example, immediately after lighting, a lamp current that is, for example, three times or more the rated lamp current flows from the chopper 22 to the metal halide lamp 27, and thereafter the lamp current is gradually reduced as time elapses, and control is performed so that the rated lamp current is eventually reached. I do. Further, the control means 23 generates a constant power control signal when the detection signals of the lamp current and the lamp voltage are fed back and performs constant power control of the chopper 22. Further, the control means 23 has a built-in microcomputer incorporating a temporal control pattern in advance, and is configured to control the lamp current.

The lamp current detecting means 24 is inserted in series with the lamp, detects the lamp current and inputs the control to the control means 23. The lamp voltage detecting means 25 is connected in parallel with the lamp, detects the lamp voltage, and performs control input to the control means 23. The starting means 26 is configured to supply a pulse voltage of 20 kV to the metal halide lamp 27 at the time of starting.

When the metal halide lamp lighting device of this embodiment is used for direct current lighting of the metal halide lamp, a required light beam is generated immediately after lighting. As a result, it is possible to realize lighting of 25% of the luminous flux with respect to the rating one second after the power is turned on, which is necessary for a vehicle headlamp, and 80% of the luminous flux after 4 seconds. Further, since a DC-AC conversion circuit is not required, cost can be reduced by about 30% as compared with AC lighting. In addition, the weight can be reduced by 15%. Accordingly, the lighting circuit becomes inexpensive.

(Fifth Embodiment) Hereinafter, a fifth embodiment of the present invention will be described.
An embodiment will be described. FIG. 7 is a diagram schematically showing a circuit of the metal halide lamp lighting device according to the present embodiment. This embodiment is different from the fourth embodiment in that a metal halide lamp is configured to be turned on by alternating current.

Reference numeral 28 denotes an AC converter. This AC conversion means 28 comprises a full-bridge inverter. That is, a bridge circuit is formed by connecting a pair of series circuits of a pair of switching means 28a and 28a in parallel between the output terminals of the chopper 22, and switching the oscillation output of the oscillator 28b in the diagonal direction of the four switching means 28a. The high frequency alternating current is generated between the output terminals of the bridge circuit by alternately supplying them to the means.

Then, the metal halide discharge lamp 27 is turned on by high-frequency alternating current. In this AC lighting type configuration, the same control as in FIG. 6 is performed.

[0081]

As described above, according to each of the first to fifth aspects of the present invention, it is possible to reduce the red light emission time at the time of starting.

According to the sixth aspect of the present invention, it is possible to provide a lighting device which is smaller than a case where a metal halide lamp filled with mercury is AC-lit.

According to the seventh aspect of the present invention, it is possible to provide an automotive headlight device having excellent safety and reliability.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a metal halide lamp according to a first embodiment.

FIG. 2 is a state diagram near the electrodes when the metal halide lamp according to the first embodiment is turned off when the metal halide lamp is turned on for 50 hours or more.

FIG. 3 is a graph showing the rising characteristics of the metal halide lamp according to the second embodiment.

FIG. 4 is a front view showing a schematic configuration of a metal halide lamp according to a second embodiment.

FIG. 5 is a perspective view showing a schematic configuration of a vehicle headlight device according to a third embodiment.

FIG. 6 is a diagram schematically showing a circuit of a metal halide lamp lighting device according to a fourth embodiment.

FIG. 7 is a diagram schematically showing a circuit of a metal halide lamp lighting device according to a fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal halide lamp 2 ... Discharge container 2a ... Discharge space 2b ... Sealing part 3 ... Electrode 3c ... Projection part 3d ... Tip side half 4 ... Metal foil 5 ... External lead 6 ... Metal halide 7 ... Free halogen

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H05B 41/24 F21W 101: 10 // F21W 101: 10 F21Y 101: 00 F21Y 101: 00 F21M 3/02 G (72) Inventor Toshihiko Ishigami 4-3-1 Higashi-Shinagawa, Shinagawa-ku, Tokyo Inside Toshiba Litec Co., Ltd. (72) Inventor Toshio Hiruta 4-3-1 Higashi-Shinagawa, Shinagawa-ku, Tokyo Toshiba Lighting Corporation (72) Inventor Mikio Matsuda 3-3-1 Higashi Shinagawa, Shinagawa-ku, Tokyo F-term in Toshiba Lighting & Technology Corporation (reference) QQ52 QQ56 QQ58 RR05

Claims (7)

[Claims] A discharge vessel having a discharge space and sealing portions provided at both ends of the discharge space; and a projection projecting into the discharge space, which is disposed so as to face from the sealing portion to the discharge space. A pair of electrodes having protruding portions; a metal foil hermetically sealed to each of the sealing portions and joined to each of the electrodes; joined to each of the metal foils and led out of the discharge vessel And a discharge medium sealed in the discharge vessel, the discharge medium containing a metal halide and a rare gas and containing essentially no mercury. When the metal halide lamp is turned off, the solid free halogen is present in the protruding portion in an amount of 0.005 mg or more and 60% by weight or more based on the total weight of the solid free halogen present in the discharge vessel. A metal halide lamp, characterized in that but attached. 2. The metal halide lamp according to claim 1, wherein the solid free halogen adhering to the projection is present in the discharge vessel at a tip half of the projection. 70% by weight or more based on the total weight of the solid free halogens. 3. The metal halide lamp according to claim 1, wherein said free halogen is at least one of iodine and bromine. 4. The metal halide lamp according to claim 1, wherein the metal halide is a halide of at least one metal selected from sodium, scandium and a rare earth element, and magnesium; Iron, cobalt, chromium, zinc, nickel, manganese, aluminum, antimony, beryllium, rhenium, gallium, titanium, zirconium, hafnium, indium, tin and cesium, and at least one metal halide. Metal halide lamp. 5. The metal halide lamp according to claim 1, wherein the lamp is in the range of 20 to 60 when stable.
A metal halide lamp that operates with W lamp power. 6. A metal halide lamp lighting device, comprising: the metal halide lamp according to claim 1; and a lighting circuit for lighting the metal halide lamp with direct current. 7. The metal halide lamp according to claim 1, wherein the metal halide lamp is provided, and the metal halide lamp has an optical axis along a longitudinal direction of the discharge vessel of the metal halide lamp. A headlight device main body; and an automotive headlight device.