JPH11219684A - Discharge lamp, discharge lamp device and light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly color rendering and highly efficient lamp by providing electrode introducing tubes at both ends of an airtight container, introducing a pair of electrodes constituted of an anode and a cathode into the airtight container from the electrode introducing tubes, and sealing a discharge medium mixed with a rare earth metal halide, a thallium halide and a tin halide at specific ratios. SOLUTION: This metal halide lamp 1 is provided with an arc tube 2 made of quartz glass and serving as an airtight container and a cylindrical tube body 3 surrounding the arc tube 2 along the longitudinal direction on the outer periphery of the arc tube 2, and they are stored and held in an outer tube 4. A discharge medium of a rare earth metal halide DyI3 (A), a thallium halide TlI (B) and a tin halide SnI2 (C) is sealed in the discharge space 5 of the arc tube 2. The desirous ratios of sealed quantities (mg/cc) are 0.1<C/A<0.34, 0.33<B/A, B/C<5.0, and 0.7<A+C<3.4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a discharge lamp, a discharge lamp device, and a light source device.

[0002]

2. Description of the Related Art Generally, metal halide lamps have been widely used for indoor store lighting and the like because of their high efficiency and high color rendering. There is a great demand for such a metal halide lamp having a relatively low wattage of about 300 W or less. Then, a halogenated DY (dysprosium), a halogenated TL,
By devising a combination of (thallium) and a halogenated CS (cesium), a metal halide lamp having higher color rendering properties and a relatively low color temperature has been obtained. For example, Japanese Unexamined Patent Publication No. Hei 7-153424 discloses a method in which the encapsulation density of dysprosium and cesium is devised.
JP-A-6-206 discloses a metal halide lamp capable of obtaining high efficiency and high color rendering characteristics at a color temperature of 00K or less.
No. 46 discloses a metal halide lamp capable of obtaining high efficiency and high color rendering characteristics at a color temperature of 4000 to 5000 K by devising a sealing density of dysprosium and thallium. Japanese Patent Application Laid-Open No. 6-168700 discloses a metal halide lamp which has high efficiency and high color rendering by devising the encapsulation density of dysprosium and cesium and is excellent for growing plants. Further, a demand for a metal halide lamp having a low color temperature of about 3500 K, which is closer to the bulb color, is increasing. For example, Japanese Patent Application Laid-Open No. 7-2967771 discloses an example in which tin iodide (SnI ₂ ), lead iodide (PbI ₂ ), or the like is used as an additive. However, only according to the publication, color temperature 3900K when used as additives iodine tin (SnI _2), color temperature 4300K when used as additives of lead iodide (PbI ₂₎ obtained Therefore, a low color temperature of about 3500K cannot be realized.

[0003]

In order to improve the color rendering of a metal halide lamp, it is necessary to enclose a rare earth halide in an arc tube and raise the temperature of the coldest part. However, in a metal halide lamp of about 300 W, the size of the arc tube electrode introduction tube becomes relatively large, so that the heat loss increases with downsizing, and it is difficult to increase the temperature of the coldest part. For this reason, the vapor pressure of the chemical sealed in the arc tube becomes low, and the color temperature becomes high, thereby lowering the color rendering. Therefore, the color rendering property can be improved by increasing the tube wall load or increasing the amount of the enclosed chemical. However, in this case, the reaction between the arc tube and the enclosed material is promoted, and devitrification occurs. There are problems that the service life is shortened and the disappearance occurs with an increase in free halogen.

On the other hand, in consideration of the high efficiency, which is another feature of the metal halide lamp, it is necessary to reduce the tube wall load and reduce the amount of chemicals in order to obtain a high efficiency and long life metal halide lamp. . However, this is inconsistent with a technique for improving color rendering.

An object of the present invention is to obtain a discharge lamp having high color rendering and high efficiency.

[0006]

According to a first aspect of the present invention, there is provided a discharge lamp including: an airtight container provided with an electrode introduction tube for introducing an anode electrode and a cathode electrode at both ends; And a pair of electrodes composed of an anode electrode and a cathode electrode, which are hermetically introduced into the container, and a rare earth metal halide, a thallium halide, and a tin halide.
g / cc) and the amount of thallium halide encapsulated in B (mg
/ Cc) and the amount of tin halide encapsulated in C (mg / cc)
In this case, 0.1 <C / A <0.34 0.33 <B / AB / C <5.0 0.7 <A + C <3.4 And a medium.

Therefore, 0.1 <C / A and 0.33
Since <B / A, the color temperature is lower than 3900K. Also, since C / A <0.34, 0.3
The efficiency when 3 <B / A is maintained at 60 (Lm / W) or more. Since B / C <5.0, duv
Does not exceed 0.0100, and the strong emission of green as a luminescent color is suppressed, resulting in good color appearance. Furthermore, 0.7 <A
Since + C, the average color rendering index Ra is 90 or more, and since A + C <3.4, the color change during life is reduced.

According to a second aspect of the present invention, there is provided an airtight container provided with an electrode introduction tube for introducing an anode electrode and a cathode electrode at both ends; an airtight container introduced from the electrode introduction tube into the airtight container. A pair of electrodes composed of an anode electrode and a cathode electrode, and a rare earth metal halide,
It contains thallium halide and tin halide, the amount of rare earth metal halide is A (mg / cc), the amount of thallium halide is B (mg / cc), and the amount of tin halide is C (mg). / Cc), a discharge sealed in an airtight container at a ratio of 0.5 <C / A <1.7 0.33 <B / A <0.83 1.0 <A + C <5.0. And a medium.

Therefore, 0.5 <C / A and 0.33
Since <B / A, the color temperature is lower than 3900K. Since C / A <1.7, 0.33
The efficiency at the time of <B / A is maintained at 60 (Lm / W) or more. Since B / A <0.83, duv
Does not exceed 0.0100, and the strong emission of green as a luminescent color is suppressed, resulting in good color appearance. Furthermore, 1.0 <A
+ C, the average color rendering index Ra is 90 or more, and since A + C <5.0, the color change during life is reduced.

According to a third aspect of the present invention, in the discharge lamp according to the first or second aspect, an outer tube covering the airtight container; and a cathode electrode is positioned above the anode electrode in the outer tube to hold the airtight container. And a holding member.

Therefore, when the discharge lamp is lit without a change in polarity, for example, as in the invention of the discharge lamp device according to the fifth aspect, a discharge lamp having a small color temperature gradient and a high color rendering and a long life is realized. That is, in order to realize a discharge lamp with high color rendering and long life, the temperature of the coldest part in the hermetic container is increased, and at that time, the temperature of other parts of the hermetic container does not excessively increase, that is, It is necessary that the temperature gradient is small. For that purpose, it is effective to perform lighting (DC lighting) without a change in polarity and to position the cathode electrode below the anode electrode. This is because, in the case of DC lighting, the vicinity of the cathode electrode is more likely to be the coldest part than in the case of AC lighting, and by positioning this at the upper side during lighting, a well-balanced lighting with a small temperature gradient is performed. Further, when the temperature gradient at the time of lighting is reduced, even if the amount of chemicals in the discharge medium sealed in the airtight container is relatively large, the color change is reduced because the chemical distribution at the time of lighting is also uniform.

The invention described in claim 4 is the first to third aspects of the present invention.
In the discharge lamp according to any one of the above, the tube wall load of the airtight container is 14 to 30 W / cm ² .

In a discharge lamp having a relatively low tube wall load of 30 W / cm ² or less, there are few problems such as leakage during the life and the life is prolonged. On the other hand, 14W / cm ²
With the above tube wall load, necessary chemical vaporization of the discharge medium sealed in the airtight container can be obtained.

[0014] The invention of a discharge lamp device according to claim 5 is as follows.
A discharge lamp according to any one of claims 1 to 4, and a lighting circuit for lighting the discharge lamp without a change in polarity.

Therefore, if the airtight container is held by positioning the cathode electrode above the anode electrode in the outer tube as in the invention of the discharge lamp according to claim 3, the temperature gradient at the time of lighting is reduced. A discharge lamp device including a discharge lamp having a low color rendering and a long life is realized. In other words, in order to realize a discharge lamp with high color rendering and long life,
The temperature of the coldest part in the hermetic container is raised, and at that time, the temperature of other parts of the hermetic container does not excessively increase, that is,
It is necessary that the temperature gradient is small. For that purpose, it is effective to perform lighting (DC lighting) without a change in polarity and to position the cathode electrode below the anode electrode.
This is because, in the case of DC lighting, the vicinity of the cathode electrode is more likely to be the coldest part than in the case of AC lighting, and by positioning this at the upper side during lighting, a well-balanced lighting with a small temperature gradient is performed. Further, when the temperature gradient at the time of lighting is reduced, even if the amount of chemicals in the discharge medium sealed in the airtight container is relatively large, the color change is reduced because the chemical distribution at the time of lighting is also uniform. In addition, when the discharge lamp is operated by alternating current, the polarity changes every half cycle, so that a re-ignition voltage appears, and the lamp goes out with the rise of the lamp voltage during the life. In the case of the DC lighting as in the invention of the present invention, since the re-ignition voltage is not generated, the possibility of extinguishing becomes extremely low. in addition,
While there is a problem that flickering occurs when the discharge lamp is turned on by alternating current, the problem of flicker does not occur in the case of direct current lighting as in the fifth aspect of the present invention.

According to a sixth aspect of the present invention, there is provided a light source device comprising: the discharge lamp according to any one of the first to fourth aspects; and a reflecting mirror that reflects light from the discharge lamp in a predetermined direction.

Therefore, the light from the discharge lamp according to any one of claims 1 to 4 is reflected by the reflecting mirror and travels in a predetermined direction. At this time, the action of the discharge lamp according to any one of claims 1 to 4 can be utilized as it is.

[0018]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG. 1 is a front view of a discharge lamp (metal halide lamp), FIG. 2 is a graph showing characteristics relating to color temperature, FIG. 3 is a graph illustrating characteristics relating to luminous efficiency, FIG. 4 is a graph illustrating characteristics relating to color appearance, and FIG. FIG. 6 is a graph showing characteristics relating to color change, and FIG. 6 is a graph showing characteristics relating to color change.

In this embodiment, a metal halide lamp 1
It is an example of application to First, an outline of the metal halide lamp 1 of the present embodiment will be described based on FIG. The metal halide lamp 1 includes an arc tube 2 as an airtight container made of quartz glass, and a cylindrical tube 3 arranged around the arc tube 2 so as to surround the arc tube 2 in the longitudinal direction. And an outer tube 4 for housing and holding the arc tube 2 and the cylindrical body 3. The cylindrical body 3 is formed of quartz glass, and the outer tube 4 is formed of hard glass.

The arc tube 2 has a discharge space 5 in the form of an ellipsoid of revolution at the center, and electrode introduction tubes 6 and 7 are formed at both ends in the major diameter direction of the discharge space 5. A cathode electrode 8 and an anode electrode 9 are opposed to each other in the major diameter direction of the discharge space 5 with a predetermined distance therebetween. The cathode electrode 8 and the anode electrode 9 are connected to metal foil conductors 10 and 11 sealed in electrode introduction tubes 6 and 7, and the metal foil conductors 10 and 11 have lead wires for power supply. 12,13
Is connected. Therefore, these lead wires 1
Reference numerals 2 and 13 are holding members for holding the arc tube 2.
Also, since the metal halide lamp 1 is used in the direction opposite to that of FIG. 1 during actual use,
The cathode electrode 8 is higher than the anode electrode 9, and the arc tube 2 is held by the lead wires 12 and 13 as holding members. The tube wall load of the arc tube 2 is 14
It is set to −30 W / cm ² .

Next, a wire mesh 14 is attached to the outer peripheral surface of the cylindrical body 3 to prevent an impact in the event that the arc tube 2 is damaged.

The discharge space 5 of the arc tube 2 is filled with a discharge medium such as a rare earth metal halide, DyI ₃ , a thallium halide, TlI, and a tin halide, SnI ₂ . See Table 1 for the amount enclosed.
As illustrated in FIG. In the present embodiment, various encapsulation amounts are illustrated, but the preferable encapsulation ratio is A (mg / cc) of DyI ₃ , which is a rare earth metal halide, and thallium halide. Tl
When the amount of I is B (mg / cc) and the amount of SnI ₂ which is a tin halide is C (mg / cc), 0.1 <C / A <0.34 0.33 <B /AB/C<5.00.7<A+C<3.4. In Table 1, there are some combinations that deviate from the above conditions, but they generally meet the above conditions.

[0023]

[Table 1]

Further, although not shown, in the present embodiment, the lighting circuit of the metal halide lamp 1 has a structure in which the metal halide lamp 1 is DC-lit, whereby the metal halide lamp 1 is lit without a change in polarity.

In such a configuration, the discharge medium sealed in the discharge space 5 of the arc tube 2 is filled with DyI ₃ which is a rare earth metal halide, TlI which is a thallium halide, and SnI ₂ which is a tin halide. Experiments were carried out by changing the ratio of the amounts as shown in Table 1, and data were collected on color temperature, luminous efficiency, color appearance, color rendering, and color change. Such experimental results will be described with reference to the graphs of FIGS.

First, the color temperature will be described with reference to the graph of FIG. In this embodiment, the ratio of the amount of enclosed and SnI ₂ is DyI ₃ and the tin halide is a rare earth metal halides, and, enclosed amount of TlI is DyI ₃ and thallium halide is a rare earth metal halide Are set to 0.1 <C / A and 0.33 <B / A, a color temperature lower than 3900K can be obtained. FIG. 2 is a graph showing the relationship between C / A and color temperature when B / A is set to 0.33. As is apparent from this graph, the color temperature is 39 within the range of 0.1 <C / A.
It becomes lower than 00K.

Next, the luminous efficiency will be described based on the graph of FIG. In the present embodiment, DyI ₃ which is a rare earth metal halide and SnI which is a tin halide
₂ and the ratio of DyI ₃ , which is a rare earth metal halide, to TlI, which is a thallium halide, in terms of C / A <0.34 and 0.33 <B /
Since it is set to A, luminous efficiency of 60 Lm / W or more can be obtained. FIG. 3 shows C / C when B / A is set to 0.33.
5 is a graph showing the relationship between A and luminous efficiency. As is clear from this graph, the luminous efficiency is 60 Lm / W or more in the range of C / A <0.34.

Next, the color will be described based on the graph of FIG. In the present embodiment, since the ratio of the amount of TlI, which is a thallium halide, to SnI ₂ , which is a tin halide, is set to B / C <5.0, duv is set.
Does not exceed 0.0100, and the strong emission of green as a luminescent color is suppressed, resulting in good color appearance. FIG. 4 shows B / C and d
It is a graph which shows the relationship with uv. As is clear from this graph, duv is 0.100 or less in the range of B / C <5.0.

Next, the color rendering properties will be described based on the graph of FIG. In the present embodiment, a rare earth metal halide DyI ₃ and a tin halide SnI ₂
Since the ratio of the amount of sealing with 0.7 was set to 0.7 <A + C,
An average color rendering index Ra of 90 or more is obtained. FIG.
9 is a graph showing a relationship between + C and an average color rendering index Ra. As is clear from this graph, 0.7 <A + C
Within this range, the average color rendering index Ra is 90 or more.

Next, the color change during life will be described based on the graph of FIG. In the present embodiment, the ratio of the amount of DyI ₃ , which is a rare earth metal halide, and SnI ₂ , which is a tin halide, is set to be A + C <3.4. Little rise. That is, there is little color change during life. FIG.
Is a graph showing the relationship between A + C and color temperature after the metal halide lamp 1 has been turned on for 1000 hours. As is clear from this graph, in the range of A + C <3.4, especially in the range of A + C <2.5, the color temperature does not increase even after lighting for 1000 hours, and the color change during life is small. I understand.

From the above, it is apparent that the metal halide lamp 1 of the present embodiment has high efficiency and high color rendering.

Further, the metal halide lamp 1 of the present embodiment is lit by direct current by the lighting circuit, that is, the lighting without changing the polarity, and the cathode electrode 8 is positioned above the anode electrode 9. Temperature gradient is reduced. For this reason, the color rendering properties are improved and the life is extended. That is, in order to realize a discharge lamp with high color rendering and long life, the temperature of the coldest part in the arc tube 2 is increased, and at that time, the temperature of other parts of the arc tube 2 is not excessively increased. That is, it is necessary that the temperature gradient be small. For that purpose, it is effective to perform lighting without changing the polarity (DC lighting) and to position the cathode electrode 8 below the anode electrode 9. This is because, in the case of DC lighting, the vicinity of the cathode electrode 8 is more likely to be the coldest part than in the case of AC lighting, and by positioning this at the top during lighting, a well-balanced lighting with a small temperature gradient is performed. Further, when the temperature gradient at the time of lighting is reduced, even if the amount of chemicals in the discharge medium sealed in the arc tube 2 is relatively large, the color distribution is reduced because the chemical distribution at the time of lighting becomes uniform. In addition, when the metal halide lamp 1 is turned on by alternating current, the polarity changes every half cycle, a re-ignition voltage appears, and the lamp voltage rises during life. In the case of DC lighting as in the embodiment, since the re-ignition voltage is not generated, the possibility of extinguishing is extremely low. In addition, while there is a problem that flicker occurs when the metal halide lamp 1 is turned on by AC, flicker does not occur in the case of DC lighting as in the present embodiment.

Further, in the present embodiment, since the tube wall load of the arc tube 2 is 14-30 W / cm ² , a long-life metal halide lamp 1 is realized. That is, 3
In the metal halide lamp 1 having a relatively low tube wall load of 0 W / cm ² or less, there are few problems such as leaks during the life and the life is extended. On the other hand, if there is a tube wall load of 14 W / cm ² or more, the necessary chemical vaporization of the discharge medium sealed in the arc tube 2 can be obtained.

A second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted. FIG. 7 is a graph showing characteristics relating to color temperature of the discharge lamp (metal halide lamp) of the present embodiment, FIG. 8 is a graph showing characteristics relating to luminous efficiency, FIG.
0 is a graph showing characteristics relating to color rendering properties, and FIG. 11 is a graph showing characteristics relating to color change.

In this embodiment, the discharge space 5 of the arc tube 2
DyI, a rare earth metal halide encapsulated inside
_3, TlI a thallium halide, an enclosed amount of SnI ₂ is a tin halide were set as illustrated in Table 2. In the present embodiment, various encapsulation amounts are illustrated, but the encapsulation amount of DyI ₃ which is a rare earth metal halide is A (mg / cc), and the encapsulation amount of TlI which is a thallium halide is B (mg). / Cc), and when the amount of SnI ₂ that is a tin halide is defined as C (mg / cc), 0.5 <C / A <1.7 0.33 <B / A <0.83 The ratio is set to be 0 <A + C <5.0.

[0036]

[Table 2]

In such a configuration, the discharge medium sealed in the discharge space 5 of the arc tube 2 is sealed with DyI ₃ which is a rare earth metal halide, TlI which is a thallium halide, and SnI ₂ which is a tin halide. Experiments were carried out by changing the ratio of the amounts as shown in Table 1, and data were collected on color temperature, luminous efficiency, color appearance, color rendering, and color change. Such experimental results will be described with reference to the graphs of FIGS.

First, the color temperature will be described with reference to the graph of FIG. In this embodiment, the ratio of the amount of enclosed and SnI ₂ is DyI ₃ and the tin halide is a rare earth metal halides, and, enclosed amount of TlI is DyI ₃ and thallium halide is a rare earth metal halide Is set to 0.5 <C / A and 0.33 <B / A, a color temperature lower than 3900K can be obtained. FIG. 7 shows the relationship between C / A and color temperature when B / A is set to 0.33 and C / A when B / A is set to 0.83.
6 is a graph showing a relationship between A and a color temperature. As is clear from this graph, the color temperature is lower than 3900K in the range of 0.5 <C / A.

Next, the luminous efficiency will be described with reference to the graph of FIG. In the present embodiment, DyI ₃ which is a rare earth metal halide and SnI which is a tin halide
₂ and the ratio of the amount of DyI ₃ , a rare earth metal halide, to the amount of TlI, a thallium halide, as C / A <1.7 and 0.33 <B / A.
, A luminous efficiency of 60 Lm / W or more can be obtained. FIG. 8 shows C / A when B / A is set to 0.33.
6 is a graph showing the relationship between the luminous efficiency and the relationship between C / A and the luminous efficiency when B / A is set to 0.83.
As is clear from this graph, the luminous efficiency is 60 Lm / W or more within the range of C / A <1.7.

Next, the color will be described with reference to the graph of FIG. In this embodiment, a rare earth metal halide DyI ₃ and a thallium halide Tl
Since the ratio of the amount enclosed with I is set to B / A <0.83, the duv does not exceed 0.0100, and the emission of green as a luminescent color is suppressed, resulting in good color appearance. FIG.
It is a graph which shows the relationship between B / A and duv. As is apparent from this graph, duv is 0.100 or less in the range of B / A <0.83.

Next, the color rendering properties will be described based on the graph of FIG. In the present embodiment, DyI ₃ which is a rare earth metal halide and SnI which is a tin halide
_Since the ratio of the amount enclosed with ₂ is set to 1.0 <A + C, an average color rendering index Ra of 90 or more can be obtained. FIG.
Is a graph showing the relationship between A + C and the average color rendering index Ra. As is clear from this graph, 1.0 <A
Within the range of + C, the average color rendering index Ra is 90 or more.

Next, the color change during life will be described with reference to the graph of FIG. In the present embodiment, the ratio of the amount of DyI ₃ , which is a rare earth metal halide, and SnI ₂ , which is a tin halide, is set to A + C <5.0. Little rise. That is, there is little color change during life. FIG. 11 is a graph showing the relationship between A + C and color temperature after the metal halide lamp 1 has been turned on for 1000 hours.
As is clear from this graph, in the range of A + C <5.0, particularly in the range of A + C <3.5, 1000
It can be seen that the color temperature does not rise even after lighting for a long time, and the color change during life is small.

From the above, it is clear that the metal halide lamp 1 of the present embodiment has high efficiency and high color rendering.

Further, if the metal halide lamp 1 according to the first or second embodiment described above is mounted on a reflector (not shown) and the light reflected from the reflector is guided in a predetermined direction, the light source device can be easily manufactured. Can be configured.
In such a light source device, since the metal halide lamp 1 has the above-described functions and effects, the light source device has high efficiency, high color rendering, and long life.

[0045]

The discharge lamp according to the first aspect of the present invention includes a rare earth metal halide, a thallium halide and a tin halide, and the amount of the rare earth metal halide is A (mg / cc). B
(Mg / cc) and the amount of tin halide encapsulated is C (mg / cc).
cc), the discharge medium is placed in an airtight container at a ratio of 0.1 <C / A <0.34 0.33 <B / AB / C <5.0 0.7 <A + C <3.4. , A discharge lamp with high efficiency and high color rendering can be obtained.

According to a second aspect of the present invention, there is provided a discharge lamp including a rare earth metal halide, a thallium halide and a tin halide, wherein the amount of the rare earth metal halide is A (mg / cc), and the amount of the thallium halide is charged. Amount B
(Mg / cc) and the amount of tin halide encapsulated is C (mg / cc).
cc), the discharge medium was sealed in an airtight container at a ratio of 0.5 <C / A <1.7 0.33 <B / A <0.83 1.0 <A + C <5.0. Therefore, a discharge lamp with high efficiency and high color rendering can be obtained.

According to a third aspect of the present invention, in the discharge lamp of the first or second aspect, an outer tube for covering the airtight container is provided,
Since the cathode electrode is positioned above the anode electrode in the outer tube to hold the airtight container, for example, the discharge lamp is lit without change in polarity as in the invention of the discharge lamp device according to claim 5. In addition, it is possible to realize a discharge lamp having a high color rendering and a long life with a small temperature gradient at the time of lighting. In addition, since the temperature gradient at the time of lighting is reduced, even if the amount of the chemical of the discharge medium sealed in the airtight container is relatively large, the chemical distribution at the time of lighting is uniform, and the color change can be reduced.

The invention described in claim 4 is the first to third aspects of the present invention.
In the discharge lamp according to any one of the above, since the tube wall load of the hermetic container is set to 14-30 W / cm ² , it is possible to obtain a long-life discharge lamp with less troubles such as leaks during its life, and The required evaporation of the chemicals for the discharge medium enclosed in the container can be obtained.

The invention of the discharge lamp device according to claim 5 is as follows.
Since the discharge lamp according to any one of claims 1 to 4 and a lighting circuit for lighting the discharge lamp without a change in polarity are provided, for example, the anode is disposed inside the outer tube as in the invention of the discharge lamp according to claim 3. If the airtight container is held with the cathode electrode positioned above the electrode, it is possible to realize a discharge lamp device equipped with a discharge lamp having a high color rendering and a long life with a small temperature gradient during lighting. In addition, since the temperature gradient during lighting is reduced, even if the amount of chemicals in the discharge medium sealed in the airtight container is relatively large,
The distribution of chemicals at the time of lighting is also uniform, and color change can be reduced. Furthermore, when the discharge lamp is turned on by alternating current, the polarity changes every half cycle, so a re-ignition voltage appears, and the lamp extinguishes with an increase in the lamp voltage during life. In the case of DC lighting as in the invention of the present invention, the possibility of extinguishing can be extremely reduced since no re-ignition voltage is generated. In addition, there is a problem that flicker occurs when the discharge lamp is turned on by AC, whereas the problem of flicker can be solved in the case of DC lighting as in the invention of claim 5.

According to a sixth aspect of the present invention, there is provided a light source device comprising the discharge lamp according to any one of the first to fourth aspects, and a reflector for reflecting light from the discharge lamp in a predetermined direction. It is possible to obtain a light source device that has the same effect as the discharge lamp according to any one of 1 to 4.

[Brief description of the drawings]

FIG. 1 is a front view of a discharge lamp (metal halide lamp) showing a first embodiment of the present invention.

FIG. 2 is a graph showing characteristics relating to a color temperature.

FIG. 3 is a graph showing characteristics relating to luminous efficiency.

FIG. 4 is a graph showing characteristics relating to color appearance;

FIG. 5 is a graph showing characteristics relating to color rendering properties.

FIG. 6 is a graph showing characteristics relating to color change.

FIG. 7 is a graph showing a color temperature characteristic of a discharge lamp (metal halide lamp) according to a second embodiment of the present invention.

FIG. 8 is a graph showing characteristics relating to luminous efficiency.

FIG. 9 is a graph showing characteristics related to color appearance.

FIG. 10 is a graph showing characteristics relating to color rendering properties.

FIG. 11 is a graph showing characteristics relating to a color change.

[Explanation of symbols]

 2: airtight container 4: outer tube 6, 7: electrode introducing tube 8: electrode, cathode electrode 9: electrode, anode electrode 12, 13: holding member

Claims (6)

[Claims] 1. An airtight container having an electrode introduction tube for introducing an anode electrode and a cathode electrode at both ends; an anode electrode and the cathode airtightly introduced from the electrode introduction tube into the airtight container. A pair of electrodes composed of an electrode and a rare earth metal halide, thallium halide and tin halide, the amount of rare earth metal halide enclosed is A (mg / cc), and the amount of thallium halide enclosed is B ( mg / cc) and the amount of tin halide encapsulated is C (mg
/ Cc), 0.1 <C / A <0.34 0.33 <B / AB / C <5.0 0.7 <A + C <3.4 And a sealed discharge medium. 2. An airtight container provided with an electrode introduction tube for introducing an anode electrode and a cathode electrode at both ends; the anode electrode and the cathode airtightly introduced into the airtight container from the electrode introduction tube into the airtight container. A rare earth metal halide, a thallium halide and a tin halide, wherein the amount of the rare earth metal halide is A (mg / cc) and the amount of the thallium halide is B (Mg / cc) and the amount of tin halide encapsulated is C (m
g / cc), it is sealed in the hermetic container at a ratio of 0.5 <C / A <1.7 0.33 <B / A <0.83 1.0 <A + C <5.0. And a discharge medium. 3. The discharge according to claim 1, further comprising: an outer tube that covers the airtight container; and a holding member that holds the airtight container with the cathode electrode positioned above the anode electrode in the outer tube. lamp. 4. The tube wall load of the airtight container is 14-30 W / c.
m ² and a claims 1 to discharge lamp of any one described 3. 5. A discharge lamp device comprising: the discharge lamp according to claim 1; and a lighting circuit for lighting the discharge lamp without a change in polarity. 6. A light source device comprising: the discharge lamp according to claim 1; and a reflecting mirror that reflects light from the discharge lamp in a predetermined direction.