JP2007273378A - Metal halide lamp and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal halide lamp of high efficiency suppressing color temperature variation. <P>SOLUTION: The metal halide lamp comprises an arc tube with a pair of electrode parts 25, 27 held in a discharge space 21 formed in a light transmitting ceramic discharge container 23 and with rare gas and a luminescent substance filled in the discharge space 21, wherein EL/Di is 3.5 or more when the maximum inner diameter of the discharge container 23 is Di (mm) and a distance between the pair of electrode parts 25, 27 is EL (mm). The luminescent substance contains a first metal halide 29 composed of one of cerium halide, praseodymium halide and neodymium halide or a mixture of them, and in addition to the first metal halide 29, a second metal halide 30 having a melting point of 680°C or lower and a boiling point of 1,550°C or higher is filled in the discharge container 23. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  According to the present invention, a pair of electrode portions is held in a discharge space formed inside a translucent ceramic discharge vessel, and a rare gas and a halide are enclosed in the discharge space, and the discharge vessel The metal halide lamp and the illuminating device are provided with an arc tube whose EL / Di is 3.5 or more, where Di (mm) is the maximum inner diameter and EL (mm) is the distance between the pair of electrode portions.

  Conventionally, quartz glass has been the mainstream material used for arc tubes of metal halide lamps, but in recent years, materials using translucent ceramics have been put into practical use. Since the translucent ceramic has higher heat resistance than quartz glass, the metal halide lamp can be lit at a higher temperature, and the lamp characteristics such as color rendering properties are improved. In addition, the translucent ceramic can increase the load on the tube wall because it has less reaction with the metal halide, unlike quartz glass, so that higher efficiency can be obtained than when quartz glass is used.

In order to achieve further efficiency, Patent Document 1 discloses that a light emitting tube having a relatively elongated shape in which sodium halide (for example, NaI) and cerium halide (for example, CeI ₃ ) are sealed in a light emitting tube. A metal halide lamp that employs a tube (a shape such that (L / D)> 5 when the inner diameter of the portion forming the discharge space in the arc tube is D and the distance between the electrodes is EL) is disclosed.

In Patent Document 2, sodium halide (for example, NaI) and halogenated praseodymium (for example, PrI ₃ ) are enclosed in an arc tube, and a relatively elongated arc tube ((L / D)> 4), a metal halide lamp adopting a shape such as 4 is disclosed.
According to the metal halide lamps of Patent Documents 1 and 2, the arc tube includes a metal halide composed of at least one of CeI ₃ , PrI ₃ , NaI, or the like, or a mixture thereof, and a portion constituting the discharge space in the arc tube. If the length is relatively long, self-absorption of sodium is reduced, and thus high efficiency can be realized.
JP 2000-501563 A JP 2003-229089 A

However, the inventor of the present application actually manufactured a metal halide lamp (referred to as “conventional lamp”) in which PrI ₃ and NaI are sealed in an arc tube with reference to the techniques described in Patent Documents 1 and 2. When turned on, the light color (color temperature) was found to fluctuate drastically.
FIG. 9 shows the result of measuring the color temperature of a metal halide lamp in the prior art.

The color temperature was measured by using a conventional lamp for 100 hours and then measuring the color temperature continuously for 2 hours at 10-minute intervals to investigate variations in the color temperature.
As shown in the figure, the conventional lamp has a maximum color temperature of 4125 (K), a minimum color temperature of 3227 (K), an average color temperature of 3663 (K), and a standard deviation indicating the fluctuation of 125 (K). K) and the color temperature were observed to fluctuate drastically.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a metal halide lamp that can highly efficiently suppress color temperature fluctuations and a lighting device including the metal halide lamp.

In order to achieve the above object, a metal halide lamp according to the present invention has a pair of electrode portions held in a discharge space formed inside a translucent ceramic discharge vessel and the discharge space. An arc tube in which a rare gas and a light emitting substance are enclosed, and the maximum inner diameter of the discharge vessel is Di (mm) and the distance between the pair of electrode portions is EL (mm), and EL / Di is 3.5 or more. In the metal halide lamp comprising: A metal compound having a temperature of 1550 ° C. or higher is encapsulated.
It is said.

Here, “melting point is 680 ° C. or lower” and “boiling point is 1550 ° C. or higher” are melting points and boiling points of ordinary metal compounds defined under 1 atm.
According to this configuration, it has been experimentally verified that a characteristic with little variation in color temperature when the lamp is lit can be obtained.
The metal compound is a metal halide, or the metal halide has at least one element selected from europium and samarium. Further, at least one of cerium halide, praseodymium halide, neodymium halide, or a mixture thereof is an iodide, bromide, or a mixture thereof.

  To achieve the above object, a lighting device according to the present invention includes a metal halide lamp, a ballast for lighting the metal halide lamp, and a lighting fixture in which the metal halide lamp is incorporated. The metal halide lamp is characterized in that it is the above.

In the metal halide lamp according to the present invention, a predetermined metal compound is sealed inside the discharge vessel. Thereby, it is possible to obtain characteristics with high efficiency and little variation in color temperature.
Since the illuminating device according to the present invention includes the above-described metal halide lamp, the illuminating device has a characteristic of high efficiency and little variation in color temperature.

Embodiments of the present invention will be described with reference to the drawings.
1. Configuration of Metal Halide Lamp FIG. 1 is a schematic diagram of a metal halide lamp according to an embodiment.
As shown in FIG. 1, the metal halide lamp 1 has an arc tube 7 housed inside an outer tube bulb 5 having a base 3 at one end. In addition, although the nozzle | cap | die 3 here is E shape, another type may be sufficient.

The outer tube valve 5 is made of, for example, hard glass, and the inside thereof is kept at a vacuum (negative pressure). In addition, although the inside of the outer tube | bulb valve 5 is maintained by the vacuum, inert gas, for example, nitrogen gas, may be enclosed.
The arc tube 7 is held inside the outer tube bulb 5 by connecting (electrically) stems 11 and 13 connected to the base 3 to a power supply unit (described later) led out from both ends thereof. In addition, power is supplied from the base 3. The stem wires 11 and 13 are usually integrated by connecting a plurality of metal wires.

2. Configuration of arc tube FIG. 2 shows an arc tube of a metal halide lamp according to an embodiment.
The arc tube 7 includes a discharge vessel 23 for forming a discharge space 21 therein, and a pair of electrode portions 25 and 27 that are opposed to each other in the discharge space 21. Substance, buffer gas, and rare gas are enclosed.

The discharge vessel 23 is made of a translucent ceramic material, such as polycrystalline alumina, and has a total transmittance of about 96 (%). As shown in FIG. 2, the discharge vessel 23 includes a light emitting unit 31 having a region where arc discharge is generated inside, and thin tube units 33 and 35 extending from both sides thereof.
The electrode parts 25 and 27 are comprised from the electrode rod (37, 39) and the electrode coil (41, 43) provided in the front-end | tip (one end in the discharge space 21) of the said electrode rod (37, 39). Yes. The electrode rods are, for example, tungsten electrode rods 37, 39 using tungsten, and the electrode coils are, for example, tungsten coils 41, 43 using tungsten.

In the electrode portions 25 and 27, the other ends of the tungsten electrode rods 37 and 39 (ends opposite to the side where the tungsten coils 41 and 43 are provided) are connected to power supply bodies 45 and 47 made of, for example, conductive cermets. The bodies 45 and 47 are hermetically sealed to the narrow tube portions 33 and 35 of the discharge vessel 23 by frit materials 51 and 53. The frit materials 51 and 53 are, for example, Dy ₂ O ₃ —Al ₂ O ₃ —SiO ₂ based materials.

For example, molybdenum coils 55 and 57 are wound around the tungsten electrode rods 37 and 39 in the gap between the tungsten electrode rods 45 and 47 and the inner peripheral surfaces of the thin tube portions 33 and 35. Yes.
In the inside of the discharge vessel 23, as a metal halide which is a luminescent material, for example, sodium iodide (hereinafter referred to as “NaI”), as well as a first metal halide 29, such as praseodymium iodide (hereinafter, referred to as “NaI”). “PrI ₃ ”) is encapsulated, and a metal compound which is a characteristic configuration of the present invention is encapsulated. As this metal compound, for example, europium iodide (hereinafter referred to as “EuI ₂ ”) which is a metal halide (referred to as “second metal halide”) 30 is used, and the operation thereof will be described later. .

3. First Embodiment (1) Lamp Configuration As a first embodiment of the metal halide lamp having the above-described configuration, a typical metal halide lamp having a power consumption of 150 W will be described.
The discharge vessel 23 has an outer diameter of 6.3 (mm) and an inner diameter Di of 4.1 (mm) at a substantially central position in the longitudinal direction (extending direction of the thin tube portion) of the arc tube 7 in the light emitting portion 31. The outer diameters of the thin tube portions 33 and 35 are 3.2 (mm) and the inner diameter is 1.0 (mm).

The distance EL between the tips of the pair of electrode portions 25 and 27 facing each other in the discharge space 21 is 32.8 (mm), the shape parameter EL / Di is 8.0, and the tube wall load WL is 30. 5 (W / cm ² ).
The tungsten electrode rods 37 and 39 have an outer diameter of 0.50 (mm) and a total length of 16.5 (mm). The power feeding bodies 45 and 47 have an outer diameter of 0.95 (mm) and a total length of 6.0 (mm). The sealing length by the frit materials 51 and 53 is about 5.0 (mm) from the ends of the thin tube portions 33 and 35.

Luminescent metal halides sealed as material is _{PrI 3,} NaI, _PrI 3 as a first metal halide 29 is 2.25 (mg), NaI is as other than the first metal halide 29 6.75 ( mg) each enclosed in a discharge vessel 23. Further, EuI ₂ which is the second metal halide 30 is enclosed in a 3.0 (mg) discharge vessel 23.

As a buffer gas, mercury (0.8 mg) and xenon (noble gas) 200 (mbar) are enclosed.
(2) Lamp Characteristics The color temperature variation of the metal halide lamp described in the first embodiment (this lamp is referred to as “first invention product”) was measured.

The measurement of the color temperature is the same as the color temperature measurement described in the above section “Problems to be solved by the invention”. After lighting for 100 hours, the color temperature is continuously measured for 10 hours at intervals of 2 minutes. The variation of color temperature was investigated.
FIG. 3 shows the color temperature measurement results of the first invention product.
As shown in the figure, the first invention product has a maximum color temperature of 4528 (K), a minimum color temperature of 4299 (K), an average color temperature of 4471 (K), and a standard deviation of 54 (K). )Met.

On the other hand, since the standard deviation of the conventional lamp described in the above section “Problems to be solved by the invention” is 125 (K), the first invention product according to the present invention is a conventional lamp. On the other hand, it can be seen that the variation in color temperature can be suppressed. The reason why the variation in color temperature is suppressed will be described later.
FIG. 4 shows the measurement results of the luminous flux maintenance factor of the first invention product.

FIG. 4 also shows the measurement results of the luminous flux maintenance factor of the first conventional product (150 W specification) for comparison. The first conventional product here is a lamp in which the second metal halide (EuI ₂ ) in the first invention product is not sealed.
As shown in FIG. 4, both the first invention product and the first conventional product maintain a luminous flux maintenance factor of 85 (%) or more with respect to the initial value even when the lighting time reaches 12,000 hours. It can be seen that the characteristics are obtained.

Particularly, in the first invention product, the luminous flux maintenance factor at 12,000 hours is 90 (%) or more, whereas in the first conventional product, the luminous flux maintenance factor at 12,000 hours is 85 (%) or more. Thus, it can be seen that the product of the first invention has better life characteristics than the first conventional product.
4). Second Embodiment (1) Lamp Configuration As a second embodiment of the metal halide lamp according to the present invention, a typical metal halide lamp having a power consumption of 200 W will be described. The metal halide lamp according to the second embodiment basically has the same configuration as that of the metal halide lamp according to the first embodiment, and the configuration different from that of the metal halide lamp according to the first embodiment will be described below. .

The discharge vessel 23 has an outer diameter of 7.4 (mm) and an inner diameter Di of 5.0 (mm) at a substantially central position in the longitudinal direction (extending direction of the thin tube portion) of the arc tube 7 in the light emitting unit 31. .
The distance EL between the tips of the pair of electrode portions 25 and 27 facing each other in the discharge space 21 is 40.0 (mm), the shape parameter EL / Di is 8.0, and the tube wall load WL is 29 ( W / cm ² ).

The metal halide encapsulated as the luminescent material is PrI ₃ , NaI, PrI ₃ is encapsulated in a 2.5 (mg) discharge vessel as the first metal halide 29, and other than the first metal halide 29 NaI is sealed in a 6.75 (mg) discharge vessel 23. Further, EuI ₂ which is a second metal halide is enclosed in a 2.0 (mg) discharge vessel 23.

Mercury as a buffer gas is enclosed in 1.1 (mg) and xenon as a rare gas is enclosed in 200 (mbar).
(2) Lamp characteristics The color temperature variation of the metal halide lamp described in the second embodiment (this lamp is referred to as “second invention product”) was measured. The measurement of the color temperature is as described above.

FIG. 5 shows the color temperature measurement results of the second invention product.
As shown in the figure, the second invention product has a maximum color temperature of 4095 (K), a minimum color temperature of 3973 (K), an average color temperature of 4046 (K), and a standard deviation of 29 (K). )Met.
With respect to the measurement result of the second invention product, the standard deviation of the conventional lamp described in the above section “Problems to be solved by the invention” is 125 (K). As with the first invention product, it can be seen that the variation in color temperature can be suppressed. The reason why the variation in color temperature is suppressed will be described later.

FIG. 6 shows the measurement results of the luminous flux maintenance factor of the second invention product.
FIG. 6 also shows the measurement result of the luminous flux maintenance factor of the second conventional product (200 W specification) for comparison. The second conventional product here is a lamp in which the second metal halide (EuI ₂ ) in the second invention product is not enclosed.
From FIG. 6, both the second invention product and the second conventional product maintain a luminous flux maintenance factor of 85 (%) or more with respect to the initial value even when the lighting time reaches 12,000 hours, and have a good lifetime. It can be seen that the characteristics are obtained.

In the second invention, the luminous flux maintenance factor at 12,000 hours is 90 (%) or more, whereas in the second conventional product, the luminous flux maintenance factor at 12,000 hours is 85 (%) or more. 4. It can be seen that the product of the second invention has better life characteristics than the second conventional product. Examination Results (1) Examination of Prior Art The inventor referred to Patent Documents 1 and 2 described in the above-mentioned “Background Art” section, and used cerium halide (hereinafter “CeX ₃ ”) in the discharge space. ), Praseodymium halide (hereinafter referred to as “PrX ₃ ”), neodymium halide (hereinafter referred to as “NdX ₃ ”), sodium halide (hereinafter referred to as “NaX”), and others. As a result of producing encapsulated metal halide lamps (the configuration other than the encapsulated material is the same as that of the first invention product) and measuring the color temperature of each encapsulated lamp, it was found that the variation was large.

The manufactured metal halide lamp contains the following six types of luminescent materials. In addition, the enclosure of the manufactured metal halide lamp uses “iodine” as a halide.
Sample 1 ... PrI ₃ -NaI (PrI ₃ : NaI = 1: 3 (Wt%))
Sample _{2 ··· CeI 3 -NaI (CeI 3} : NaI = 1: 3 (Wt%))
Sample 3 ... NdI ₃ -NaI (NdI ₃ : NaI = 1: 3 (Wt%))
Sample _{4 ··· DyI 3 -NaI (DyI 3} : NaI = 1: 3 (Wt%))
Sample 5... HoI ₃ -NaI (HoI ₃ : NaI = 1: 3 (Wt%))
Sample 6 TmI ₃ -NaI (TmI ₃ : NaI = 1: 3 (Wt%))
FIG. 7 shows the measurement result of the color temperature of each sample and its analysis result.

The measurement method is the same as the color temperature measurement described in the column “Problems to be Solved by the Invention” above. The measurement result of FIG. 9 shows the first result of the sample 1 and the change in time on the horizontal axis. Are plotted.
In addition, FIG. 7 shows an average value (“Average” in the figure), a maximum value (“Max” in the figure), and a minimum value (“Min” in the figure) for each sample. And standard deviation (“σ” in the figure) are collectively shown. FIG. 7 shows the two measurement results and the average value for each sample.

As is apparent from FIG. 7, the standard deviation “σ” indicating the variation in color temperature is large as 158 (K), 152 (K), and 137 (K), and the color temperature varies greatly. You can see that
On the other hand, samples 4 to 6 in which rare earth metal halides are encapsulated as the encapsulating material have small standard deviations “σ” indicating variations in color temperature as small as 43 (K), 26 (K), and 16 (K). It can be seen that the color temperature fluctuations of samples 1 to 3 encapsulating CeX ₃ , PrX ₃ , NdX ₃ , and NaI are very large.

Furthermore, the inventor tends to increase the color temperature variation when the shape parameter EL / Di indicating the shape of the arc tube is smaller than 3.0, and the color temperature variation is small when the shape parameter EL / Di is larger than 4.0. It was also found from various tests.
(2) Consideration The inventor considered the reason why the variation of the color temperature is large as follows.

(2-1) Shape parameter <3.0
When the shape parameter EL / Di is smaller than 3.0, the arc tube has a relatively thick shape. For example, when the lamp is turned on with its axis centered horizontally, the coldest spot of the arc tube exists at the lower part of the light emitting unit. It will be. At this time, the metal halide as the inclusion is agglomerated in the vicinity of the lower portion of the light emitting portion, which is the coldest point.

When the lighting of the lamp is stabilized, the variation in the coldest spot temperature of the light emitting portion is small, and the variation (change) in the vapor pressure of the metal halide is thereby reduced. For this reason, it is considered that the variation in color temperature is reduced. In addition, when the enclosure contains sodium halide, there is a problem that the self-absorption of sodium increases and lamp efficiency decreases.
(2-2) Shape parameter> 4.0
When the shape parameter EL / Di is larger than 4.0, the arc tube has a relatively thin shape. For example, when the lamp is turned on with its axis centered horizontally, the coldest spot of the arc tube exists in the narrow tube portion. Become. Also in this case, the metal halide that is the inclusion is aggregated in the vicinity of the inside of the narrow tube portion that is the coldest point.

Since the inner peripheral surface of the narrow tube portion and the outer peripheral surface of the coil made of molybdenum are very close to each other, when the metal halide (metal iodide) aggregates in liquid form on the inner surface of the thin tube portion, the liquid metal halide is formed. Contact with the molybdenum coil occurs.
On the other hand, since the coil made of molybdenum has a tungsten electrode rod wound around it, the surface temperature when the lamp is lit is very high, and if the liquid metal halide comes into contact with the molybdenum coil, the metal halide is abrupt. Evaporation (sudden boiling) occurs. The inventor has thought that this evaporation (vaporization) causes a drastic increase (change) in vapor pressure in the discharge space, resulting in a large change in color temperature.

When the shape parameter EL / Di is larger than 4.0, the shape of the arc tube becomes elongated, and even if NaI is contained as the inclusion, the self-absorption of sodium is reduced and the efficiency is increased.
(3) Invention Based on the above examination, the metal halide lamp was developed by increasing the shape parameter EL / Di to increase the lamp efficiency and with little color temperature fluctuation.

Naturally, the color temperature fluctuation should be small regardless of the shape parameter. When the shape parameter El / Di is smaller than 3.0, the inventors have found that the variation in color temperature is small. Therefore, the variation in the color temperature is suppressed when the shape parameter EL / Di is 3.0 or more. It would be good if you could.
However, when the shape parameter EL / Di is close to 3.0, even if there is a variation in the color temperature, it is not so large, so if the variation in the color temperature can be suppressed when the shape parameter EL / Di is 3.5 or more, it is practical. It seems that there is no problem.

As a result of various studies, the inventor has found that, in addition to the first metal halide which is a luminescent substance, a second metal halide having a boiling point of 680 (° C.) or lower and a boiling point of 1550 (° C.) or higher (EuI ₂ in the examples). It is found that the variation in color temperature can be suppressed by enclosing it in the discharge space, and the reason is estimated as follows.
First, in a ceramic metal halide lamp, it is considered that the temperature distribution of about 700 (° C.) to about 1500 (° C.) exists in the longitudinal direction of the inside of the thin tube portion (the portion communicating with the light emitting portion) during lamp operation. It is done. The lowest temperature 700 (° C.) is the temperature at the inner surface of the thin tube portion and away from the electrode portion, and the highest temperature 1500 (° C.) is the inner surface of the thin tube portion and close to the tungsten coil. The temperature of the part.

CeX ₃ , PrX ₃ , and NdX ₃ encapsulated as the first metal halide have a relatively low melting point and a relatively high boiling point, so that even a high-temperature portion around the electrode portion is a liquid without being evaporated. Exists as.
On the other hand, when a second metal halide having a melting point of 680 (° C.) or lower and a boiling point of 1550 (° C.) or higher is enclosed, the second metal halide is also evaporated at a high temperature portion around the electrode portion, which is a narrow tube portion. Without being in liquid form. Since the second metal halide has a boiling point of 1550 (° C.), which is considered to be slightly higher than the temperature of the molybdenum coil at the time of lighting, for example, even if the second metal halide remains liquid, It does not evaporate on contact.

When the second metal halide comes into contact with the molybdenum coil during lighting (a state in which the molybdenum coil is coated), the light-emitting substance (first metal halide) CeX ₃ or the like Is no longer in direct contact with the molybdenum coil as in the prior art.
That is, the second metal halide enters between the narrow tube portion and the molybdenum coil and acts as a buffer material, and can prevent rapid evaporation (bumping) of CeX _{3 and the} like. As a result, the inventor speculated that the fluctuation of the vapor temperature in the discharge space is small and the fluctuation of the color temperature can be suppressed.

From the above, in order to effectively suppress the color temperature change of the lamp, one or more of CeX ₃ , PrX ₃ , and NdX ₃ is selected as the first metal halide that is the luminescent material, and the second metal As a halide, a substance that liquefies at a temperature in a narrow tube portion of a ceramic metal halide lamp and does not evaporate even when it comes into contact with an electrode rod during lighting, more specifically, a melting point of 680 (° C.) or less and a boiling point of 1550 It was thought that it would be sufficient to use a substance having a temperature of (° C.) or higher.

It has also been found that EuX ₂ and SmX ₂ hardly react with the discharge vessel (alumina ceramic), and do not affect the life characteristics, so the second metal halide is europium (Eu) or samarium (Sm) as a metal. If at least one element is included, the generation of free iodine can be suppressed, and the fluctuation of vapor pressure in the discharge space due to the generation of free iodine can also be suppressed. As a result, other lamp characteristics (color rendering properties, Duv (black) We thought that it would lead to the suppression of change of deviation from body trajectory x 1000)).

As described above, the present invention has been described based on the embodiments. However, the content of the present invention is not limited to the specific examples shown in the above embodiments, and for example, the following modifications are further provided. Can be implemented.
1. Substance of First Metal Halide In each of the above embodiments, iodide is used as the first metal halide. However, bromide or a mixture of iodide and bromide may be used.

2. Substance of Second Metal Halide Iodide is used as the second metal halide in each of the above embodiments, but bromide or a mixture of iodide and bromide may be used.
Examples of metal halides having a melting point of 680 ° C. or lower and a boiling point of 1550 ° C. or higher include strontium iodide (SrI ₂ ), strontium bromide (SrBr ₂ ), and ytterbium bromide (YbBr ₂ ). There is a slight decrease.

On the other hand, europium iodide _(EuI 2), europium bromide (EuBr _2), because the samarium iodide _(SmI 2), is preferable to use a samarium bromide (SMBR _2), decrease in lamp efficiency is hardly observed, It can be said that this is a more preferable embodiment in the present invention.
3. Metal Halide Lamp (1) Type The configuration of the arc tube according to each of the above embodiments can be applied as it is to types other than 150 W and 250 W of each embodiment, such as 70 W, 100 W, 200 W, 400 W, and the like.

In the embodiment, the single-metal E-type metal halide lamp has been described. However, for example, a double-cap type that has the base on both sides of the lamp may be used.
(2) Arc tube In each of the above embodiments, the light emitting portion of the arc tube has a straight tube shape, but other shapes, for example, a barrel shape in which the central portion in the longitudinal direction of the light emitting portion is thicker than both sides thereof. The shape may be such that the central portion becomes thicker in stages. Naturally, conversely, the central portion of the light emitting portion may be thinner than both sides. Furthermore, the shape may be such that the thickness gradually (stepwise) changes from one end of the light emitting unit to the other end.

When the inner diameter of the light emitting portion changes in the longitudinal direction, the maximum value of the inner diameter is used as “Di” of “EL / Di” indicating the shape parameter.
Moreover, the cross-sectional shape of the discharge vessel may be circular, or may be a polygonal shape such as an elliptical shape or a hexagonal shape. For example, when the cross section is a hexagonal shape, the inner diameter of the present invention is the dimension of the longest line segment on the diagonal line.

(3) Electrode part Although the electrode rod and electrode coil in each embodiment used tungsten, it can also be constituted using other materials, for example, molybdenum.
Furthermore, in each embodiment, the light emitting part and the thin tube part are made of a single material and integrated. For example, the light emitting part and the thin tube part made of the same material are manufactured separately. And what united both may be sufficient.

4). Illumination Device FIG. 8 is a schematic view of an illumination device according to the present invention.
As shown in FIG. 8, the lighting device 100 includes, for example, a lighting fixture 103 attached to a mounting wall 101 and a metal halide lamp 1 attached to the lighting fixture 103.
The luminaire 103 includes a trumpet-shaped reflecting member 105 that expands on the irradiation side, a socket portion 107 that is disposed in the reflecting member 105 and for detachably mounting the metal halide lamp 1, and a metal halide lamp that is mounted on the socket portion 107. And a ballast 109 for lighting 1, and the outer periphery of the reflection member 105 is mounted in contact with a mounting hole 101 a formed in the attachment wall 101.

As shown in FIG. 8, the metal halide lamp 1 is mounted on the socket portion 107 with its axis being horizontal. The metal halide lamp 1 can also use a lamp as described in the above modification.
The inner peripheral surface of the reflecting member 105 is finished to be a mirror surface or is coated with a white paint so that light emitted from the metal halide lamp 1 efficiently irradiates the front. A base plate 111 extending in a direction (vertical direction in FIG. 8) parallel to the main surface of the attachment wall 101 is attached to one end of the reflection member 205, and a portion corresponding to the inside of the reflection member 105 in the base plate 111 A socket portion 107 is attached to the socket. A ballast 109 is housed inside a housing 113 provided in a portion corresponding to the outside of the reflecting member 105.

  The present invention can be applied to a metal halide lamp and a lighting device that are highly efficient and have little variation in color temperature.

It is the schematic of the metal halide lamp which concerns on 1st Embodiment. The arc tube of the metal halide lamp of 1st Embodiment is shown. The color temperature measurement result of the first invention product is shown. The measurement result of the luminous flux maintenance factor of the 1st invention item is shown. The color temperature measurement results of the second invention product are shown. The measurement result of the luminous flux maintenance factor of the 2nd invention item is shown. It is a measurement result of the color temperature change of each sample. It is the schematic of the illuminating device which concerns on this invention. The color temperature measurement result of the metal halide lamp in a prior art is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lamp 7 Light emission tube 25,27 Electrode part 29 1st metal halide 30 2nd metal halide 31 Light emission part 33,35 Narrow tube part 200 Illumination device

Claims (5)

A pair of electrode portions are held in a discharge space formed inside a translucent ceramic discharge vessel, and a rare gas and a luminescent material are sealed in the discharge space, and the maximum inner diameter of the discharge vessel is increased. Di (mm), where a distance between the pair of electrode portions is EL (mm), a metal halide lamp including an arc tube whose EL / Di is 3.5 or more,
The luminescent material includes at least one of cerium halide, praseodymium halide, neodymium halide, or a mixture thereof, and a metal having a melting point of 680 ° C. or lower and a boiling point of 1550 ° C. or higher inside the discharge vessel. A metal halide lamp characterized by containing a compound. The metal halide lamp according to claim 1, wherein the metal compound is a metal halide. The metal halide lamp according to claim 2, wherein the metal halide has at least one element selected from europium and samarium. 4. The metal halide according to claim 1, wherein at least one of cerium halide, praseodymium halide, neodymium halide, or a mixture thereof is iodide, bromide, or a mixture thereof. 5. lamp. In a lighting device comprising a metal halide lamp, a ballast for lighting the metal halide lamp, and a lighting fixture in which the metal halide lamp is incorporated,
The said metal halide lamp is a metal halide lamp described in any one of Claims 1-4. The illuminating device characterized by the above-mentioned.

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