JPH08180798A - Metal vapor discharge lamp and lighting apparatus therefor and projection apparatus using thereof - Google Patents

Abstract

PURPOSE: To prevent degradation of light transmissive function of a light emitting tube and prevent temperature rise by preventing occurrence of devitrification and sublimation in an insulating sleeve formed on an electrode shaft. CONSTITUTION: A metal vapor discharge lamp is provided with a bulb 2 made of quartz glass, a pair of electrodes 4 sealed in the bulb 2, an insulating sleeve 9 formed on the base parts 5 of these electrodes 4, and layers 90, 95 consisting of a nitrogen component and formed on the surface of tip part including at least the tip face of the insulating sleeve. Since the layer consisting of a nitrogen component is formed on the insulating sleeve, the surface of the insulating sleeve becomes hard to be recrystallized and heat resistance is improved and devitrification and sublimation are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal vapor discharge lamp, and more particularly to a short arc type metal vapor discharge lamp, its lighting device, and a light projecting device using the same.

[0002]

2. Description of the Related Art Generally, a metal vapor discharge lamp has a high luminous efficiency and is widely used in various fields. Especially, a short arc type lamp having an electrode distance of 20 mm or less is a reflection because it is close to a point light source. It is used in a light projecting device in combination with an optical system such as a mirror, and its application is expanding to product lighting, spot lighting, and a projection device such as a projector.

In this type of short arc type metal vapor discharge lamp, the distance between the electrodes is extremely short in order to make it compact and compact. For this reason, since the difference between the distance between the electrode tips and the distance between the electrode roots is small, a normal discharge that should originally occur at the electrode tip portion may occur between the one electrode tip and the other electrode root or between the electrode tips. May occur between roots. In particular, if mercury or luminescent metal is attached to the base of the electrode, an arc will easily fly to the base of the electrode. When such a discharge other than the normal discharge occurs, the root of the electrode is eroded and broken at an early stage, or the sealing portion near the base of the electrode is heated, which causes cracks.

Therefore, the present applicant has filed Japanese Patent Application Laid-Open No. 1-2203
As disclosed in Japanese Patent Laid-Open No. 62-62, it has been proposed that the base of the electrode be covered with an insulating sleeve such as a quartz tube to prevent discharge from occurring at the base of the electrode. According to this structure, the electrode root is covered with the insulating sleeve, so that the root discharge can be reliably prevented.

Further, when the base of the electrode is covered with an insulating sleeve such as quartz as described above, the rare earth metal enclosed in the valve may react with the electrode shaft to erode the electrode shaft, which is prevented. Therefore, as shown in FIG.
A means of covering the root of the above with double insulating sleeves 51 and 61, the inner insulating sleeve 51 is made of an alumina tube, and the outer insulating sleeve 61 is made of a quartz tube is also under study. In addition, in place of the alumina tube, a means of forming an alumina coating on the base of the electrode shaft and covering the outside with a quartz tube 61 has been studied. In this case, since the base of the electrode shaft is covered with alumina, the reaction between the rare earth metal and the electrode shaft is suppressed. Note that, in FIG. 9, other structures may be the same as those of the embodiment of FIG. 1 described later, and therefore, the same reference numerals are used and description thereof is omitted.

[0006]

However, in the conventional case as described above, in order to prevent discharge at the electrode base, it is effective to increase the height of the insulating sleeve to bring the tip closer to the arc spot. However, in this case, the tip end face and the tip end portion of the insulating tube receive the heat from the discharge and the heat from the arc spot, and the temperature rises significantly.

In the conventional case, since the tip surface and the tip of the insulating tube are formed of quartz, when the temperature of the tip surface and the tip of the tube rises significantly, the tip of the insulating tube devitrifies. Or it may sublimate. When quartz sublimes, the insulating tube becomes shorter, and vaporized components adhere to the inner surface of the bulb, causing the arc tube to become cloudy, which reduces the light transmission performance and raises the temperature inside the bulb. To be done.

The present invention has been made in view of the above circumstances. An object of the present invention is to prevent the insulating sleeve from devitrification or sublimation, thereby deteriorating the light transmission performance of the arc tube or reducing the temperature. It is intended to provide a metal vapor discharge lamp, a lighting device for the same, and a light projecting device using the same, which can prevent problems such as rising of the lamp.

[0009]

The invention according to claim 1 is provided with a bulb made of quartz glass, a pair of electrodes sealed in the bulb, and an insulating sleeve covering the bases of these electrodes. A metal vapor discharge lamp, comprising: a layer formed of a nitrogen component on a surface of a tip portion including at least a tip surface of the insulating sleeve.

The invention of claim 2 is characterized in that the insulating sleeve is formed of a quartz tube.
The metal vapor discharge lamp according to 1. A third aspect of the invention is the metal vapor discharge lamp according to the first or second aspect, wherein the layer formed of the nitrogen component formed on the insulating sleeve is a nitriding modified layer.

According to a fourth aspect of the present invention, in addition to mercury and a rare gas, a metal halide is enclosed in the bulb, and the discharge lamp is a metal halide lamp. Item 3. A metal vapor discharge lamp according to any one of items 3.

A fifth aspect of the present invention is the metal vapor discharge lamp according to any one of the first to fourth aspects, wherein the bulb has a structure in which one side is sealed. The invention of claim 6 is a short arc type discharge lamp in which a distance between electrodes is 20 mm or less and both ends of a bulb are sealed, and a short arc type discharge lamp according to any one of claims 1 to 5. It is a metal vapor discharge lamp.

The invention of claim 7 is characterized by comprising the metal vapor discharge according to any one of claims 1 to 6 and a lighting circuit for lighting the discharge lamp. It is a lighting device of an electric lamp.

According to an eighth aspect of the present invention, there is provided a metal vapor discharge according to any one of the first to sixth aspects, and a reflector that reflects the light emitted from the discharge lamp and irradiates the front. A floodlighting device characterized by being provided.

[0015]

According to the invention of claim 1, in the insulating sleeve, a layer made of a nitrogen component, for example, a film of silicon nitride (Si ₃ N ₄ ) or aluminum nitride (AlN) is formed on at least the tip surface including the tip surface. Since the coating layer or the nitriding modified layer (Si ₃ N ₄ ) is formed, the surface of the insulating sleeve is less likely to be recrystallized, heat resistance is improved, and devitrification and sublimation can be prevented.

According to the second aspect of the invention, since the insulating sleeve is formed of the quartz tube, the insulating property is maintained by the quartz tube, and since the layer made of the nitrogen component is formed on the surface, the heat resistance is improved. .

According to the third aspect of the invention, since the layer formed of the nitrogen component formed on the insulating sleeve is a nitriding modified layer, it can be integrally molded with the insulating sleeve and peeled off like a coating or a layer. Does not occur.

According to the invention of claim 4, since a metal halide is enclosed in the bulb in addition to mercury and a rare gas, the bulb becomes a metal halide lamp excellent in luminous efficiency and color rendering, and these characteristics are effective. Since it will be used as a light source, the field of application will expand.

According to the fifth aspect of the invention, since the bulb has the one-sided sealing structure, the pair of electrodes extends from the single sealing portion to the light emitting space, and the pair of electrodes easily come close to each other.
In particular, the base parts of the electrodes are close to each other, and a base discharge is likely to occur,
If the present invention is applied to such a single-sealed discharge lamp, remarkable effects can be obtained.

According to the sixth aspect of the present invention, even in a discharge lamp with both ends sealed, since a pair of electrodes are close to each other in a short arc type discharge lamp having a distance between electrodes of 20 mm or less, a root discharge is generated. When the present invention is applied to such a lamp, a remarkable effect can be obtained.

According to the invention of claim 7, it is possible to provide a lighting device which makes use of the characteristics of the metal vapor discharge according to any one of claims 1 to 6. According to the invention of claim 8, the floodlight utilizing the characteristics of the metal vapor discharge lamp according to any one of claims 1 to 6, in particular, the short arc type metal vapor discharge lamp effective as a point light source. A device can be provided.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the first embodiment shown in FIGS. This embodiment shows an example applied to a metal halide lamp having a single-sealed double tube structure. In FIG. 2, reference numeral 1 denotes an arc tube of a small metal halide lamp having a single-sealed structure, and the arc tube 1 of this lamp is It is housed in the outer pipe 10 to form a double pipe structure.

As shown in FIG. 1 (A), the arc tube 1 is provided with a bulb 2 made of quartz glass, and the bulb 2 has, for example, a substantially spherical light emission with an inner diameter of 12.0 mm. There is a space, and the crushing sealing portion 3 is formed at one end thereof. A pair of electrodes 4 and 4 are sealed in the sealing portion 3.

The electrodes 4 and 4 are constructed by winding electrode coils 6 and 6 made of tungsten wire or thoriated tungsten, etc. around the tips of electrode shafts 5 and 5 made of tungsten or rhenium wire, respectively. The pair of electrode coils 6, 6 are opposed to each other with a predetermined inter-electrode distance of 20 mm or less, for example, 6 mm in the light emitting space.

The electrode shafts 5 and 5 are connected to the metal foil conductors 7 and 7 made of molybdenum, which are sealed in the crushing and sealing portion 3. These metal foil conductors 7, 7 have external lead wires 8, 8
Are connected, and the external lead wires 8 and 8 are crushed and sealed.
It is derived from the end face of.

Insulating sleeves 9 and 9 are covered on the roots of the electrode shafts 5 and 5, respectively. These insulating sleeves 9, 9 are made of, for example, a quartz tube, and the base end portions thereof are embedded in the crushing sealing portion 3 together with the end portions of the electrode shafts 5, 5, and the tip end portions thereof are the tip ends of the electrode shafts 5, 5. A predetermined length m is exposed to cover other regions.

A layer 90 of a nitrogen compound is formed on at least the tip surface and the surfaces of the tip portions of the insulating sleeves 9, 9. In the case of this embodiment, the nitrogen compound layer is a layer 90 obtained by nitriding and modifying the surface of quartz, as shown in FIG.

Now, the nitriding modified layer will be described.
Quartz nitriding modification means silica SiO ₂ which is a component of quartz.
Is a layer formed by substituting the oxygen component O _{2 in the above} with nitrogen N, and becomes Si ₃ O ₄ .

When the quartz tube is heated to a high temperature in an atmosphere of ammonia (NH ₃ ) in the nitride reformed layer 90, a reaction as shown in the following "Chemical formula 1" occurs, and this reaction causes the silica SiO ₂ to change. Oxygen O ₂ therein is replaced with nitrogen N to be formed.

[0030]

Embedded image

In such a modified nitriding layer 90, the nitrogen concentration changes continuously decreasing from the surface of the quartz tube to the inside thereof, and there is no clear boundary, and the nitrogen concentration is maximum on the outermost surface. Has become.

In the bulb 2, as a luminescent metal, for example, sodium Na, indium In, lithium Li, tin S are used.
An iodide and bromide such as n or thallium Tl are enclosed, a predetermined amount of mercury is enclosed as a buffer metal, and an argon gas is enclosed as a rare gas.

The metal halide lamp having such a structure is housed in the one-sealed outer tube 10 to form a double tube structure. The outer tube 10 has a crushed sealing portion 11 at one end, and the sealing portion 11 has metal foil conductors 12, 12 made of molybdenum.
Is sealed. The outer lead wires 8, 8 of the arc tube 1 housed in the outer tube 10 are connected to the metal foil conductors 12, 12. External power supply lines 13 and 13 are connected to the metal foil conductors 12 and 12. An inert gas is filled in the outer tube 10.

A metal halide lamp having a single-sealed double-tube structure is constructed in this manner.
As shown in, the commercial power supply 21 is connected via the lighting circuit 20. The lighting circuit 20 includes a well-known ballast and the like, and constitutes the lighting device of the present invention.

Further, the above-mentioned metal halide lamp having a single sealed double tube structure can be attached to the lighting fixture shown in FIG. 3 to be used as spot lighting. In FIG.
Reference numeral 30 denotes a housing which serves as a main body of the lighting fixture. In this housing 30, a reflecting mirror 32 and a socket 33 are attached to a mounting plate 31 at a ceiling portion, and the above-mentioned lamp detachably attached to the socket 33 is attached to the reflecting mirror 32. It will be housed.

In the metal halide lamp having such a structure, when power is supplied to the arc tube 1 through the lighting circuit 20, a discharge is generated between the electrodes 4 and 4, whereby the luminescent metal is ionized and excited to emit light. When attached to a lighting fixture as shown in FIG. 3, the light emitted from the lamp is reflected by the reflecting surface of the inner surface of the reflecting mirror 32 and illuminates the lower side.
Therefore, it becomes spot lighting.

In this lamp, the bases of the electrode shafts 5 and 5 are covered with the insulating sleeves 9 and 9, so that the tip of one electrode and the base of the other electrode, and between the bases of both electrodes are thereby covered. It is possible to prevent discharge from occurring.

In addition, since the insulating sleeves 9 and 9 have the nitriding / modifying layer 90 formed on the surface of quartz, the nitriding / modifying layer 90 has a property that it is difficult to recrystallize. It withstands higher temperatures and is less likely to cause devitrification or sublimation.

From this, the insulating tubes 9 and 9 are shortened, or the vaporized component of quartz adheres to the inner surface of the bulb 2 to make the arc tube cloudy, which reduces the light transmission performance and raises the temperature inside the bulb. It is possible to prevent such troubles as

Further, since the heat resistance strength of the tips of the insulating tubes 9 and 9 becomes high, the tips of the insulating tubes 9 and 9 can be brought close to the tips of the electrode shafts 5 and 5, that is, the arc spot, and the insulating tube 9 The distance m between the tips of the electrodes 9 and 9 and the tips of the electrode shafts 5 and 5 can be reduced. Therefore, the exposed range of the electrode shafts 5, 5 is reduced, and it is possible to further prevent discharge other than regular discharge.

In the above embodiment, since the insulating sleeves 9, 9 are made of quartz tubes, the quartz tubes can keep the insulating properties of the electrode shafts 5, 5 excellent, and the nitriding modified layer 90 can be formed. Can be easily formed,
Heat resistance is improved. Further, the nitriding modified layer 90 does not peel off or fall off unlike the nitrogen compound coating.

If the bulb 2 has a single-sided sealing structure as described above, the pair of electrodes 4, 4 extends from the single sealing portion 3 into the light emitting space. The electrodes 4 and 4 are easily approached, and especially the roots of the electrode shafts 5 and 5 are easily approached to easily generate root discharge. However, when the present invention is applied to such a single-sealed discharge lamp, a remarkable effect is obtained. Can be obtained.

When a metal halide is enclosed in the bulb 2 in addition to mercury and a rare gas, a metal halide lamp is obtained, which is a lamp excellent in luminous efficiency and color rendering. Therefore, these characteristics can be effectively utilized. It can be used for lighting products such as shops.

Furthermore, as shown in FIG. 2, a lighting device in which this lamp is connected to a commercial power source 21 via a lighting circuit 20 can provide a lighting device that effectively utilizes the advantages of the above lamp.

The insulating sleeves 9 and 9 are used in the above embodiment.
Although the nitriding modified layer 90 is formed on the surface of the above, the present invention is not limited to this, and as in the second embodiment shown in FIG. 4, silicon nitride (Si ₃ N ₄ ) or Even if a coating 95 of a nitrogen compound such as aluminum nitride (AlN) is formed, the heat resistance strength can be increased and devitrification and sublimation can be prevented.

Further, it is the tip of the insulating sleeve 9 that receives the heat particularly in the insulating sleeve 9. Therefore, as in the third embodiment shown in FIG. A nitride modified layer or a nitrogen compound coating may be formed over the entire length.

The lamp shown in FIG. 2 has a double tube structure in which the arc tube 1 is housed in an outer tube 10 made of quartz glass, but the present invention is the same as the fourth example shown in FIG. A downlight type floodlighting device having a double tube structure in which the arc tube 1 is integrated with the reflecting mirror 40 may be used. To describe the structure in this case, the single-sealed arc tube 1 is housed in the envelope 40. The envelope 40 includes a reflector 41 and the reflector 41.
And a front glass 42 that hermetically closes the front opening of the above, forms a sealed space, and the arc tube 1 is housed in this sealed space. The inside of the envelope 40 is kept in a vacuum. That is, the envelope 40 has the same function as the outer tube 10 described above.

The reflector 41 is made of, for example, quartz glass,
It is provided with a reflecting portion 43 formed of a rotation curve and a concave portion 44 connected to the reflecting portion 43, and the inner portion of the concave portion 44 is closed by a closing wall 45. On the inner surfaces of the reflection part 43 and the recess 44, a reflection film 46 made of an aluminum vapor deposition film or the like is formed.

Support wires 47, 47 also serving as a pair of conductive wires are hermetically penetrated through the closing wall 45 of the reflector 41, and the ends of the support wires 47, 47 extending inside the reflector 41 are sealed. The external lead wires 8 of the arc tube 1 are joined to each other. Therefore, arc tube 1
Are mechanically supported and electrically connected to the support wires 47, 47. The support wires 47, 47 are connected to the shell 49a of the base 49 and the external terminals 49b via connecting wires 48, 48. In the downlight illumination device having such a configuration, a part of the light emitted from the arc tube 1 directly passes through the front glass 42, and the rest of the light is a reflective film 46 formed on the inner surface of the reflector 41.
Is reflected by the front glass 42, passes through the front glass 42, and illuminates the front (lower side).

In the downlight illuminating device having such a structure, the base of the electrode of the arc tube 1 is covered with the insulating sleeve 9, and the surface of the insulating sleeve 9 is coated with the nitrogen compound 95 or the nitriding modified layer 90. Is formed by
Discharge can be prevented from occurring between the tip of one electrode and the root of the other electrode, and between the roots of both electrodes, and the heat resistance of the insulating sleeve 9 is improved.
Devitrification and sublimation are less likely to occur.

Further, in the above embodiment, the lamp using the single-sealed arc tube 1 was described, but the present invention is not limited to this, and the double-ended sealed arc tube shown in FIG. 7 and FIG. It can be implemented even when used. FIG. 7 shows a lamp with both ends sealed, 101 is an arc tube, 102 is its quartz bulb,
Reference numerals 103, 103 denote crushing sealing portions formed on both ends, 10
4, 104 are electrodes, 105, 105 are electrode shafts, 106,
Reference numeral 106 indicates an electrode coil. In this case, the distance between the electrodes is 2
It is formed to be 0 mm or less, for example, 18 mm. Electrode shaft 10
At the root of Nos. 5 and 105, FIG.
Alternatively, the insulating sleeves 109, 109 shown in FIG. 5 are covered. The electrode shafts 105, 105 are sealing parts 103, 1
It is connected to the external lead wires 108 and 108 through the metal foils 107 and 107 which are sealed to 03.

The arc tube 101 as described above is housed in the outer tube 110 having both ends sealed to form a double tube structure. The outer tube 110 has crushed sealing portions 111 and 111 at both ends, and metal foil conductors 112 and 112 made of molybdenum are sealed to the sealing portions 111 and 111. External lead wires 108, 108 of the arc tube 101 housed in the outer tube 110 are connected to the metal foil conductors 112, 112. The metal foil conductors 112, 112 are connected to the external power supply line 11
It is connected to the bases 114, 114 via 3, 113.

Such a lamp can be attached to the lighting fixture shown in FIG. 8 and used as spot lighting. In FIG. 8, reference numeral 130 denotes a housing that serves as a main body of the lighting fixture. In this housing 130, a first reflecting mirror 132 and a second reflecting plate 133 are attached to a mounting plate 131 on the ceiling.
Is attached. The lamp has a first reflecting mirror 132.
Attached to.

Also in the lamp having such a structure, the base of the electrode is covered with the insulating sleeve 109, and the surface of the insulating sleeve 109 is formed by the nitrogen compound coating 95 or the nitriding modified layer 90. It is possible to prevent discharge from occurring between the tip of one electrode and the root of the other electrode, and between the roots of both electrodes, and the heat resistance of the insulating sleeve 109 is improved to prevent devitrification or sublimation. It is hard to occur.

Further, when the lamp is attached to the luminaire as shown in FIG. 8, the light emitted from the lamp is reflected by the inner reflecting surfaces of the reflecting mirrors 131 and 132 and illuminates the lower side. Therefore, it becomes spot lighting. Although the metal halide lamp has been described in each of the embodiments, a mercury lamp in which mercury and a rare gas are enclosed in the arc tube can be used.

[0056]

As described above, according to the invention of claim 1, the insulating sleeve has a layer of a nitrogen component, such as silicon nitride (Si ₃
N ₄ ), aluminum nitride (AlN) and other coatings or coatings, or a modified nitriding layer (Si ₃ N ₄ ), the insulating sleeve surface is less likely to recrystallize and the heat resistance is improved. It is possible to prevent devitrification and sublimation. As a result, the insulating tube becomes shorter, the vaporized components of quartz adhere to the inner surface of the bulb, and the arc tube becomes cloudy, which reduces the light transmission performance and raises the temperature inside the bulb. Can be prevented.

According to the second aspect of the present invention, since the insulating sleeve is formed of the quartz tube, the insulating property is maintained by the quartz tube, and the layer made of the nitrogen component is formed on the surface, so that the heat resistance is improved.

According to the third aspect of the invention, since the layer composed of the nitrogen component is the nitriding modified layer, it can be integrally formed with the insulating sleeve, and peeling off or falling off like a film or a layer having a different structure. Does not happen.

According to the invention of claim 4, since a metal halide is enclosed in the bulb in addition to mercury and a rare gas, a metal halide lamp excellent in luminous efficiency and color rendering is obtained, and these characteristics are effective. Since it will be used as a light source, the field of application will expand.

According to the fifth aspect of the invention, since the bulb has the single-sided sealing structure, the pair of electrodes extends from the single sealing portion to the light emitting space, and the pair of electrodes are easily brought close to each other.
In particular, the base parts of the electrodes are close to each other, and a base discharge is likely to occur,
If the present invention is applied to such a single-sealed discharge lamp, remarkable effects can be obtained.

According to the sixth aspect of the present invention, even in a discharge lamp with both ends sealed, since a pair of electrodes are close to each other in a short arc type discharge lamp having an electrode distance of 20 mm or less, a root discharge is generated. When the present invention is applied to such a lamp, a remarkable effect can be obtained.

According to the invention of claim 7, it is possible to provide a lighting device utilizing the characteristics of the metal vapor discharge according to any one of claims 1 to 6. According to the invention of claim 8, the floodlight utilizing the characteristics of the metal vapor discharge lamp according to any one of claims 1 to 6, in particular, the short arc type metal vapor discharge lamp effective as a point light source. A device can be provided.

[Brief description of drawings]

1A and 1B show a first embodiment of the present invention, FIG. 1A is a sectional view of an arc tube, and FIG. 1B is an enlarged sectional view of an insulating sleeve thereof.

2A and 2B are a sectional view and a diagram of a lighting device of a single-sealed double-tube metal halide lamp using the arc tube of FIG.

FIG. 3 is a cross-sectional view of a lighting device using the same sealed double-tube metal halide lamp.

FIG. 4 is an enlarged sectional view of an insulating sleeve according to the second embodiment of the present invention.

FIG. 5 is an enlarged sectional view of an insulating sleeve according to the third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a lamp with a reflecting mirror according to a fourth embodiment of the present invention.

FIG. 7 shows a fifth embodiment of the present invention, in which both ends are sealed.
Sectional drawing of a heavy pipe type metal halide lamp.

FIG. 8 is a cross-sectional view of a lighting device using the double-ended metal halide lamp of the same sealed type.

FIG. 9 is a sectional view of a conventional arc tube.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Arc tube 2 ... Quartz bulb 3 ... Sealing part 4 ... Electrode 5 ... Electrode shaft 6 ... Electrode coil 9 ... Insulation sleeve 90 ... Nitriding modified layer 95 ... Nitrogen compound coating 10 ... Outer tube 30 ... Housing (lighting fixture) Main body) 32 ... Reflecting mirror 40 ... Envelope 41 ... Reflector 42 ... Front glass 43 ... Reflecting part 46 ... Reflecting surface 49 ... Base 101 ... Arc tube 102 ... Quartz bulb 103 ... Sealing part 104 ... Electrode 105 ... Electrode shaft 106 ... Electrode coil 109 ... Insulation sleeve 110 ... Outer tube 130 ... Housing (lighting equipment main body) 132, 133 ... Reflector

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01J 61/86

Claims (8)

[Claims] 1. A bulb made of quartz glass, a pair of electrodes sealed in the bulb, an insulating sleeve covering the bases of these electrodes, and a surface of a tip portion including at least a tip surface of the insulating sleeve. And a layer comprising a nitrogen component. 2. The metal vapor discharge lamp according to claim 1, wherein the insulating sleeve is formed of a quartz tube. 3. The layer made of a nitrogen component formed on the insulating sleeve is a nitriding modified layer.
Alternatively, the metal vapor discharge lamp according to claim 2. 4. The bulb contains a metal halide in addition to mercury and a rare gas, and the discharge lamp is a metal halide lamp.
A metal vapor discharge lamp according to claim 3. 5. The metal vapor discharge lamp according to claim 1, wherein the bulb has a structure in which one side is sealed. 6. The metal vapor according to claim 1, which is a short arc type discharge lamp in which a distance between electrodes is 20 mm or less and both ends of a bulb are sealed. Discharge lamp. 7. A lighting device for a metal vapor discharge lamp, comprising: the metal vapor discharge according to any one of claims 1 to 6; and a lighting circuit for lighting the discharge lamp. 8. A metal vapor discharge according to any one of claims 1 to 6, and a reflector for reflecting the light emitted from the discharge lamp and irradiating the light forward. And a floodlighting device.