JP2005285559A - Metal halide lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic metal halide lamp of modulated light type which suppresses fluctuation of light emitting color of rise of color temperature when lighting modulated light. <P>SOLUTION: This metal halide lamp is provided with: a light emitting vessel made of a ceramic material and composed of a central main pipe part forming a discharge space and thin pipe parts extended from its both ends; a pair of feeding bodies extending in hollow parts of the thin pipe parts; a sealing material sealing an opening end part of the thin pipe part; and a light emitting substance sealed in the discharge space. The light emitting substance is composed of a basic component and an auxiliary component. The basic component is made of halide of rare earth metal, halide of sodium, and halide of magnesium. The auxiliary component is made of halide of mercury. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal halide lamp.

  In recent years, a metal halide lamp using a translucent polycrystalline alumina ceramic (PCA) tube instead of quartz as a material for a luminous container has been actively developed and deployed. Although the heat resistance of quartz is about 1000 ° C., the PCA tube has a high heat resistance of about 1200 ° C., and accordingly the tube wall load of the arc tube can be set to a high range. Therefore, if a PCA tube is used, lamp characteristics with high efficiency and high color rendering properties can be obtained. The PCA tube is also excellent in molding accuracy and resistance to corrosion reactions. Improvement in molding accuracy reduces variations in color temperature, and improvement in corrosion resistance enables a longer lamp life.

  Metal halide lamps (ceramic metal halide lamps) using PCA tubes have been developed mainly for indoor interior lighting in stores and the like, and a low wattage type of 70 to 150 W has been put into practical use. Recently, a 200-300 W high watt type ceramic metal halide lamp has been developed for outdoor lighting.

  A general arc tube is composed of a central main tube portion that forms a discharge space and a thin tube portion that is extended from both ends of the main tube portion, and a pair of power supply bodies extend in the hollow of the thin tube portion. The power feeder is composed of an electrode support made of a tungsten electrode and niobium or conductive cermet. The gap between the electrode support and the inner wall of the thin tube portion is hermetically sealed with a sealing material made of frit.

A luminescent substance is sealed in the discharge space. The luminescent substance, iodide dysprosium (DyI _3), iodide thulium (TmI _3), iodide holmium (HoI _3), cerium iodide (CeI _3), rare earth metals such as iodide praseodymium (PrI ₃₎ And a combination of halides such as thallium iodide (TlI) and sodium iodide (NaI) are used. The former halide emits a multi-line spectrum due to atoms and a continuous spectrum due to molecules, and the latter emits a line spectrum.

  The discharge space is filled with mercury as a buffer gas and inert gas such as argon as a start assisting gas. The arc tube is accommodated in a state where it is supported by a predetermined jig in an outer tube glass bulb in which a gas such as nitrogen is sealed and a base is mounted (see Patent Document 1).

  Among the ceramic metal halide lamps as described above, for example, a 150 W type lamp, which is the main product, achieves excellent lamp characteristics with a lamp efficiency of 90 lm / W and an average color rendering index Ra85 or more. Further, the rated life time of a metal halide lamp using a conventional light emitting container made of quartz is 6000 hours, whereas the rated life time of 9000 hours is obtained with a ceramic metal halide lamp. Note that, by changing the composition of the luminescent material, three types having lamp light colors with color temperatures of 3000K, 3500K, and 4300K have been developed.

  In recent years, in the lighting field, energy saving is required from the viewpoint of protecting the global environment. Under such circumstances, development and development of a so-called dimming lamp capable of setting the lamp input power to a level lower than 100% in accordance with the use environment has been promoted. Therefore, development of dimming ceramic metal halide lamps for indoor lighting is currently under investigation.

  However, when a metal halide lamp is lit at a lamp input power lower than 100%, the emission color generally varies greatly. The main factor is that when the lamp input power is lowered and dimming lighting is performed, the coldest spot temperature of the tube wall of the arc tube is lowered, and the vapor pressure of the luminous material in the arc tube is lowered. That is, since each component constituting the luminescent material has a different rate of decrease in vapor pressure, the radiation spectrum distribution varies and the lamp emission color varies.

For example, conventional _{DyI 3, TmI 3, HoI 3} , TlI and when the light-emitting material comprising a NaI was shown to 150W type ceramic metal halide lamps and the lamp input power 60% lighting dimming encapsulation, following experimental values obtained It has been. First, the color temperature Tc is about 4300 K when the lamp input power is 100%, but rises to about 5100 K when the lamp input power is 60%. The displacement duv of the chromaticity coordinates (u, v) from the black body radiation locus is 0 when the lamp input power is 100%, but increases to 20 when the lamp input power is 60%. Further, the average color rendering index Ra is 90 when the lamp input power is 100%, but decreases to 70 when the lamp input power is 60%. Such a phenomenon is mainly the proportion of under vapor pressure of TlI, compared to the proportion of under vapor pressure of the other rare earth metal halide (DyI _3, TmI ₃ and HoI _3), due to the smaller.

  As described above, when a conventional metal halide lamp is dimmed with a lamp input power lower than 100%, the lamp emission color and color rendering properties vary relatively greatly. Such fluctuations are at a level that is difficult to tolerate for indoor lighting lamps.

Therefore, instead of TlI, luminescent substances using at least one of magnesium iodide (MgI ₂₎ and magnesium bromide (MgBr _2), for example a luminescent material comprising _{DyI 3, TmI 3, HoI 3} , MgI 2 and NaI It has been proposed to use. The rate of change in vapor pressure of MgI ₂ and MgBr ₂ when dimming is turned on is substantially the same as the rate of change in vapor pressure of halides of rare earth metals that are other luminescent materials (see Patent Document 2).

When at least one of MgI ₂ and MgBr ₂ is used instead of TlI and the lamp is dimmed with an input power of 60%, for example, the following experimental values are obtained. First, the rise of the color temperature Tc is suppressed to 4600K even when the lamp input power is 60%, compared to 4400K when the lamp input power is 100%. Further, the displacement duv of the chromaticity coordinates is 5 when the lamp input power is 100%, and is 4 even when the lamp input power is 60%. Further, the average color rendering index Ra is suppressed to 75 even when the lamp input power is 60%, compared to 92 when the lamp input power is 100%. Therefore, the light color characteristic at the time of dimming lighting is greatly improved, and is approaching a level applicable to indoor lighting.
JP 2003-272560 A JP 2002-42728 A

As described above, in response to the demand for energy saving, development of a dimming type ceramic metal halide lamp using at least one of MgI ₂ and MgBr ₂ instead of TlI has been promoted. The displacement duv of the degree coordinate is improved. However, it cannot be said that the rise in the color temperature Tc of the lamp during dimming can be sufficiently suppressed.

  For example, the color temperature Tc may increase to 4800K when the lamp input power is 60%, compared to 4200K when the lamp input power is 100%. Such emission color fluctuations are at a level that can be clearly recognized even by sensitivity evaluation by human eyes, and are still difficult to allow for indoor lighting. Therefore, in order to commercialize a dimming type ceramic metal halide lamp, it is desired to further suppress the variation in the color temperature Tc during dimming lighting.

The present invention is a halide of a rare earth metal luminescent material as a base component comprises sodium halide and a halide of magnesium, halides of rare earth metal iodide dysprosium (DyI _3), iodide thulium (TmI ₃ ), iodide holmium (HoI _3), at least one selected from the group consisting of cerium iodide (CeI ₃₎ and iodide praseodymium (PrI _3), halide magnesium iodide magnesium (MgI ₂₎ In addition, in a metal halide lamp that is at least one selected from the group consisting of magnesium bromide (MgBr ₂ ), it is an object to further suppress emission color fluctuations such as a rise in color temperature during dimming lighting. And it aims at providing the light control type ceramic metal halide lamp which can be applied also to indoor lighting, such as a store.

That is, the present invention provides: (a) a luminous vessel made of a ceramic material comprising a central main tube portion forming a discharge space and a narrow tube portion having an outer diameter smaller than the main tube portion extended from both ends of the main tube portion; A) a pair of power supply bodies extending in the hollow of the narrow tube portion; (c) a sealing material that seals the open end of the thin tube portion; and (d) a luminescent material enclosed in the discharge space. The basic component is composed of rare earth metal halide, sodium halide and magnesium halide, the subcomponent is composed of mercury halide, and the rare earth metal halide is composed of a DyI _3, TmI _3, HoI _3, CeI ₃ and PrI least one selected from the group consisting of _3, the halide of magnesium, consists of MgI ₂ and MgBr ₂ At least one selected from the halide mercury relates a metal halide lamp is at least one selected from the group consisting of mercuric iodide (HgI ₂₎ and mercuric bromide (HgBr _2).

  The ratio of mercury halide in the total of rare earth metal halide, sodium halide, magnesium halide and mercury halide is preferably 1 to 9.2 mol%.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to control suitably the light emission state of rare earth metals at the time of the light control lighting of a lamp, and emission color fluctuations, such as a raise of the color temperature of a lamp at the time of light control lighting, can be suppressed effectively. . Therefore, a dimming type ceramic metal halide lamp that can be applied to indoor lighting can be obtained.

  Further, according to the present invention, by controlling the ratio of mercury halide in the total of the rare earth metal halide, sodium halide and magnesium halide to 1 to 9.2 mol%, While suppressing the emission color variation of the lamp at the time of lighting, a rated life time of about 9000 hours, for example, equivalent to the conventional lamp can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing the internal structure of an example of the arc tube of the present invention, and FIG. 2 is an enlarged cross-sectional view of the vicinity of the narrow tube portion of the arc tube.
The luminous container of the arc tube 100 is made of PCA material. The luminous container includes a central main pipe portion 101 and narrow pipe portions 102 and 103 having an outer diameter smaller than that of the main pipe portion 101 extended from both ends thereof. The inside of the main pipe portion 101 becomes a discharge space (discharge arc region). The central main pipe part 101 and the thin pipe parts 102 and 103 are joined by sintering. In addition, a light emitting container in which the central main tube portion and the thin tube portion are integrally formed can be used.

  The power feeders extend in the hollows of the thin tube portions 102 and 103, respectively. The pair of power feeders includes an electrode having a tip disposed in the discharge space and an electrode support extended from the terminal of the electrode. The pair of electrodes is composed of two parts, that is, electrode rods 104 and 105 made of tungsten and coils 106 and 107 made of tungsten. The ends of the electrode rods 104 and 105 are connected to the ends on the discharge space side of the electrode supports 108 and 109, respectively. The electrode supports 108 and 109 are fixed to the thin tube portions 102 and 103 by a sealing material 110, respectively. Electrode leads 116 and 117 are connected to end portions of the electrode supports 108 and 109 that protrude outward from the thin tube portions 102 and 103, respectively.

The electrode supports 108 and 109 are made of niobium or conductive cermet, and Al ₂ O ₃ —Mo based conductive cermet is preferably used. The electrode leads 116 and 117 are made of niobium or the like. The sealing material 110 is made of a glass frit, and a Dy ₂ O ₃ —Al ₂ O ₃ —SiO ₂ frit is preferably used. The sealing material 110 also serves to hermetically seal the open ends of the thin tube portions 102 and 103.

  The sealing material 110 may be corroded by a light emitting material when the lamp is turned on. In order to suppress this, the sealing material 110 is filled only to the hollow joint portions of the thin tube portions 102 and 103, for example, the electrode rods 104 and 105 and the electrode supports 108 and 109. The joints between the electrode rods 104 and 105 and the electrode supports 108 and 109 have a relatively low temperature even when the lamp is lit. Thus, normally, the sealing material 110 is filled up to a position away from the hollow discharge space of the thin tube portions 102 and 103. Coiles 111 and 112 made of molybdenum are usually provided in the gap between the inner walls of the narrow tube portions 102 and 103 that are inevitably formed and the electrode rods 104 and 105. These coils also suppress the erosion of the sealing material 110 by a high-temperature luminescent material when the lamp is lit.

The luminescent material 113 enclosed in the discharge space is composed of a basic component and a subcomponent. A person skilled in the art can appropriately select the amount of the light-emitting substance enclosed by the input power of the lamp.
The basic component includes at least one rare earth metal halide selected from the group consisting of DyI ₃ , TmI ₃ , HoI ₃ , CeI ₃ and PrI ₃ , a sodium halide, and a group consisting of MgI ₂ and MgBr _2. And at least one magnesium halide selected from the group consisting of

The composition of the basic components can be appropriately selected by those skilled in the art depending on the input power of the lamp. However, among the halides of the rare earth metals, from the viewpoint of obtaining excellent color rendering Ra and lamp efficiency, it is preferred to use at least DyI _3, TmI ₃ and HoI _3. In that case, it is preferable that at least TmI ₃ occupies 30 mol% or more of the halide of all rare earth metals. NaI is preferably 40 to 55 mol% of the total luminescent material. Magnesium halide is preferably 15 to 25 mol% of the total luminescent material.

  At the time of dimming lighting, the vapor pressure of the luminescent material is lower than when the input power is 100% lighting. At this time, the halide of magnesium causes a change in vapor pressure at almost the same rate as the halide of rare earth metal. Therefore, even when the dimming is turned on, the emission color variation of the lamp is suppressed to some extent.

  However, the light emission state of the rare earth metal also changes during dimming lighting. That is, rare earth metals emit light mainly in a molecular state called a halide when the input power is 100%, but emit light mainly in an atomic state during dimming lighting because the existence probability of the molecular state decreases. Such a transition from molecular emission to atomic emission changes the emission spectrum. Therefore, even in a lamp in which the rate of change in vapor pressure of the luminescent substance is controlled, emission color fluctuations occur.

In order to suppress the transition from molecular light emission to atomic light emission as described above and to suppress the emission color fluctuation to a high degree, it is effective to include the following subcomponent in the light emitting substance. Here, the accessory component is composed of at least one mercury halide selected from the group consisting of HgI ₂ and HgBr ₂ . By including such a subcomponent in the light emitting substance, the existence probability of the rare earth metal in the molecular state is increased even when the light is lit, and molecular light emission mainly occurs even when the light is lit. Furthermore, since the vapor pressure is increased when the molecular emission increases, the emission spread of sodium D-line also increases. As a result of these effects, it is possible to effectively suppress emission color variations such as an increase in the color temperature of the lamp during dimming lighting.

  The ratio of mercury halide in the total of rare earth metal halide, sodium halide, magnesium halide, and mercury halide is preferably 1 to 9.2 mol%, More preferably, it is 2.4 to 6.2 mol%. If the amount of mercury halide is less than 1 mol%, the effect of suppressing emission color fluctuation due to addition of mercury halide cannot be sufficiently obtained. On the other hand, if the amount of mercury halide exceeds 9.2 mol%, the so-called halogen cycle action causes the tungsten electrode rod or coil to be eroded relatively severely, and the luminous flux maintenance factor decreases. Lamp life characteristics deteriorate.

  In the discharge space, mercury 114 is sealed as a buffer gas, and an inert gas is sealed as a starting auxiliary gas. The amount of these substances enclosed varies depending on the input power of the lamp. A person skilled in the art can appropriately select a preferable amount.

  FIG. 3 is a side view of an example of a metal halide lamp including the arc tube of FIG. The outer glass bulb is shown in cross section to show the internal structure. The metal halide lamp 300 has an outer tube glass bulb 301 filled with nitrogen or the like. The arc tube 100 is housed and fixed in the inner space of the outer tube glass bulb 301. Hard glass or the like is used as the material of the outer tube glass bulb 301. A base 302 is attached to the root of the outer tube glass bulb 301.

  One electrode lead 117 led out from the narrow tube portion of the arc tube 100 is positioned below. The other electrode lead 116 of the arc tube 100 is located above. A stem glass 304 protrudes from the root of the outer tube glass bulb 301. Stem leads 305 and 307 are sealed on the stem glass 304. The electrode lead 117 is fixed and electrically connected to the stem lead 305. The electrode lead 116 is fixed and electrically connected to a support lead 308 extended from the stem lead 307. A quartz shield tube 309 is provided around the arc tube 100. The quartz shield tube 309 has a role of preventing the outer tube glass bulb 301 from being damaged.

Comparative Example 1

  An arc tube having a typical size as shown in FIGS. 1 and 2 was produced, and a ceramic metal halide lamp with a lamp input of 150 W as shown in FIG. 3 was produced. The dimensions of the arc tube are as follows. The nitrogen sealing pressure in the outer tube glass bulb was 46.5 kPa, and the rated color temperature was 4300K.

Inner diameter of central main pipe φi: 10.7mm
Distance between electrodes Le: 10 mm
Outer diameter of narrow tube part: 3.2 mm
Inner diameter of narrow tube: 1.0mm
Total length of narrow tube part: 14.2mm
Electrode rod outer diameter: 0.45 mm
Total length of electrode rod: 16.5 mm
External diameter of electrode support: 0.90 mm
Total length of electrode support: 6.0 mm
Depth of penetration of sealing material into narrow hollow part (sealing length): 3.35mm

The following materials were sealed in the discharge space of the arc tube.
Mercury content: about 10mg
Starting auxiliary gas (argon): about 20 kPa
Luminescent substance DyI ₃ : 10.3 mol%
TmI ₃ : 10.2 mol%
HoI ₃ : 10.3 mol%
MgI ₂ : 18.0 mol%
NaI: 51.2 mol%
Total amount of luminescent material: 4.9 mg

[Evaluation 1]
The resulting lamp of Comparative Example 1 was dimmed and the relationship between lamp input power and color temperature Tc was examined. FIG. 4 shows a graph X1 (broken line) in which the relationship is plotted. As is apparent from FIG. 4, the color temperature Tc at the time of 60% dimming lighting with the lamp input power of 90 W is greatly increased from about 4200 K at about 100% lighting with the lamp input power of 150 W to about 4800 K. This is a variation that can be clearly recognized by the sensitivity evaluation by the human eye.

  Next, the relationship between the input power of the lamp of Comparative Example 1 and the displacement duv of the chromaticity coordinates was examined. FIG. 5 shows a graph X2 (broken line) in which the relationship is plotted. The displacement duv at the time of 60% dimming lighting with the lamp input power of 90 W varies from about −4.5 at about 100% lighting with the lamp input power of 150 W to about −6.0. This variation is relatively small and acceptable.

  Further, the relationship between the input power of the lamp of Comparative Example 1 and the color rendering property Ra was examined. FIG. 6 shows a graph X3 (broken line) in which the relationship is plotted. The color rendering property Ra at 60% dimming lighting with a lamp input power of 90 W varies from 90 to 80 at 100% lighting with a lamp input power of 150 W. This variation is also relatively small and within an acceptable range.

A ceramic metal halide lamp with a lamp input of 150 W similar to Comparative Example 1 was produced except that the composition of the luminescent material was changed.
The composition and amount of the luminescent material are shown below.
DyI ₃ : 9.9 mol%
TmI ₃ : 9.8 mol%
HoI ₃ : 9.9 mol%
MgI ₂ : 17.3 mol%
NaI: 49.2 mol%
HgI ₂ : 3.9 mol%
Total amount of luminescent material: 5.2 mg

[Evaluation 2]
The resulting lamp of Example 1 was dimmed and the relationship between lamp input power and color temperature Tc was examined. A graph Y1 (solid line) in which the relationship is plotted is shown in FIG. The color temperature Tc at the time of 60% dimming lighting with the lamp input power of 90W increases from about 4200K at the time of 100% lighting with the lamp input power of 150W to about 4450K, which is an acceptable level fluctuation.

  Next, the relationship between the input power of the lamp of Example 1 and the displacement duv of the chromaticity coordinates was examined. FIG. 5 shows a graph Y2 (broken line) in which the relationship is plotted. The displacement duv at the time of 60% dimming lighting with the lamp input power of 90 W varies from about −1.8 to about −0.2 at the time of 100% lighting with the lamp input power of 150 W. This variation is relatively small and acceptable.

Further, the relationship between the input power of the lamp of Example 1 and the color rendering property Ra was examined. FIG. 6 shows a graph Y3 (broken line) in which the relationship is plotted. The color rendering property Ra at the time of 60% dimming lighting with the lamp input power of 90 W varies from 88 to 78 at the time of 100% lighting with the lamp input power of 150 W. This variation is also relatively small and within an acceptable range.
The above results are at a level that can be sufficiently applied as a lamp for indoor lighting.

  As shown in Evaluations 1 and 2, so-called halogen surplus, to which mercury halide is added, is used to suppress the emission color variation of the lamp during dimming lighting to a level that can be sufficiently applied for indoor lighting. It is extremely effective to use the luminescent material.

FIG. 7 shows the radiation spectrum distribution of the lamp of Comparative Example 1 when the input power is 100% turned on and when 60% dimming is turned on. FIG. 8 shows the radiation spectrum distribution of the lamp of Example 1 when the input power is 100% and 60% dimming. In comparison to FIGS. 7 and 8, in particular, and emission spread of D line of Na in the vicinity governs the color temperature 590～600Nm, are differences in the continuous component due to rare earth metal molecules such as DyI _3, TmI _3, HoI ₃ It can be seen. The displacement of the radiation spectrum distribution corresponding to the lamp input power is smaller in Example 1 (FIG. 8) than in Comparative Example 1 (FIG. 7). The emission color variation of the lamp is caused by the displacement of the radiation spectrum distribution. Mercury halides such as HgI ₂ have the effect of suppressing such a shift in the radiation spectrum distribution.

Next, in the composition of the luminescent material, mercury halide (HgI ₂ ) in the total of the rare earth metal halide, sodium halide, magnesium halide, and mercury halide (HgI ₂ ). Various lamps similar to those in Example 1 were produced except that the ratio was changed, and the same evaluation as in Example 1 was performed. As a result, it became clear that the ratio of HgI ₂ is preferably in the range of 1 to 9.2 mol%. That is, when the ratio of HgI ₂ is less than 1 mol%, the effect of suppressing the emission color variation may not be sufficiently obtained. On the other hand, when the proportion of HgI ₂ exceeds 9.2 mol%, the lamp life characteristics may be deteriorated. The reason why the life characteristic is deteriorated is that the tungsten electrode coil is eroded by excessive halogen, and the luminous flux maintenance factor of the lamp is lowered.

9, a halide of a rare earth metal, and sodium halides, and halides of magnesium, relative to the total of the mercury halide (HgI _2), the proportion of mercury halides (HgI ₂₎ is 3 The result of the life test in the case of mol% is shown. In the life test, a cycle life test was performed in which lighting with 100% lamp input power and lighting with 60% were alternately repeated for 0.5 hours. According to FIG. 9, a rated life time of 9000 hours or more is obtained for the lamp. Therefore, the lamp of the present invention has excellent life characteristics equivalent to or better than those of conventional lamps.

Then, a lamp using the HgBr ₂ instead of HgI _2, a lamp using equimolar and HgI ₂ and HgBr _2, prepared in the same manner as in Example 1, was evaluated in the same manner as in Example 1. As a result, the effect of suppressing the emission color fluctuation at the time of dimming lighting was obtained as in Example 1, and the life characteristics were also the same as in Example 1.

  In addition, even when an arc tube having the same configuration as described above is applied to a lamp for indoor lighting other than the rated color temperature of 4300K, the same effect as described above for suppressing emission color variation at the time of dimming lighting can be obtained, The life characteristics were also good. For example, the same effect was also obtained in varieties such as rated color temperatures of 3000 K and 3500 K, low wattage types other than 150 W (for example, 70 W), high wattage types for outdoor lighting, and the like.

  As described above, according to the present invention, it is possible to suppress emission color variation such as an increase in the color temperature of the lamp, particularly during dimming lighting, and thus a dimming type ceramic metal halide lamp that can be applied to indoor lighting in stores and the like is obtained. It is done. The present invention can be applied to any metal halide lamp in which any rare earth metal halide, alkali metal halide, alkaline earth metal halide or the like is enclosed.

It is sectional drawing which shows the internal structure of an example of the arc_tube | light_emitting_tube based on this invention. It is an expanded sectional view near the narrow tube part of the arc tube concerning the present invention. It is an example of the light control type metal halide lamp which comprises the arc tube which concerns on this invention, Comprising: It is the side view which made the outer tube glass bulb the cross section in order to show an internal structure. It is a figure which shows the relationship between lamp input electric power and color temperature Tc. It is a figure which shows the relationship between lamp input electric power and chromaticity coordinate displacement duv. It is a figure which shows the relationship between lamp input electric power and color rendering property Ra. It is a radiation spectrum distribution map at the time of 100% input power lighting of the lamp of Comparative Example 1 and 60% dimming lighting. It is a radiation spectrum distribution map at the time of 100% input power lighting of the lamp of Example 1 and 60% dimming lighting. It is a figure which shows the relationship between lamp lighting time and luminous flux maintenance factor at the time of lighting repeatedly with lamp input power of 100% and lighting of 60% every 0.5 hours.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Light emission tube 101 Central main part 102, 103 Narrow tube part 104, 105 Electrode rod 106, 107 Coil 108, 109 Electrode support body 110 Sealing material 111, 112 Coil 113 Luminescent substance 114 Mercury 116, 117 Electrode lead

300 Metal halide lamp 301 Outer tube glass bulb 302 Base 304 Stem glass 305, 307 Stem lead 308 Support lead 309 Quartz shield tube

Claims (2)

(A) a luminous vessel made of a ceramic material comprising a central main pipe part forming a discharge space and a narrow pipe part extending from both ends of the main pipe part and having a smaller outer diameter than the main pipe part;
(B) a pair of power supply bodies extending in the hollow of the narrow tube portion;
(C) a sealing material that seals the open end of the narrow tube portion, and (d) a luminescent material enclosed in the discharge space,
The luminescent material consists of a basic component and subcomponents,
The basic component comprises a rare earth metal halide, a sodium halide and a magnesium halide, and the subcomponent comprises a mercury halide,
Halides of the rare earth metal iodide dysprosium (DyI _3), from the iodide thulium (TmI _3), iodide holmium (HoI _3), cerium iodide (CeI ₃₎ and iodide praseodymium (PrI ₃₎ At least one selected from the group consisting of:
The magnesium halide is at least one selected from the group consisting of magnesium iodide (MgI ₂ ) and magnesium bromide (MgBr ₂ ),
The mercury halide is a metal halide lamp which is at least one selected from the group consisting of mercury iodide (HgI ₂ ) and mercury bromide (HgBr ₂ ). The mercury halide accounts for 1 to 9.2 mol% of the total of the rare earth metal halide, the sodium halide, the magnesium halide, and the mercury halide. The metal halide lamp according to claim 1.

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