JP3378361B2 - Metal halide lamp, illumination optical device and image display device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal halide lamp used in general lighting, optical equipment, etc., an illuminating optical device in which a metal halide lamp and a concave reflecting mirror are combined, and an image display device such as a projection type liquid crystal display.

[0002]

2. Description of the Related Art In recent years, metal halide lamps have been widely used for general lighting such as store lighting and road lighting, and the demand for them is expanding as lighting for automobiles or light sources for optical equipment. An example of the metal halide lamp described above will be described below with reference to the drawings.

FIG. 1 shows the structure of a single tube metal halide lamp. In FIG. 1, 1 is a light emitting part of a quartz glass arc tube, 2 is a tungsten electrode installed via a molybdenum foil 10, 3 is a sealing part which hermetically seals the molybdenum foil 10, and 4 is an external lead wire. is there.

The operation of the metal halide lamp constructed as shown by the above components will be described below.

In the metal halide lamp, the metal halide added to the arc tube together with mercury and rare gas is
While the lamp is lit, it melts and exists as a liquid near the inner wall of the arc tube, while part of it vaporizes and vaporizes, and the evaporated metal halide vapor dissociates into metal atoms and halogen atoms at the high temperature part of the arc center. Then, the metal vapor is excited by an arc and emits a spectrum peculiar to the metal. Therefore, the metal halide lamp has an advantage that it is superior in luminous efficiency and color rendering property to the high pressure mercury lamp. And as a metal iodide, Tl-Na-In, Sc-Na, Dy-Tl,
Many metal halide lamps including Dy-Nd-Cs have been put into practical use.

[0006]

Generally, in this kind of metal halide lamp, the emission characteristics of the lamp are determined by the vapor pressure of the enclosed metal halide. That is,
In order to obtain the emission spectrum peculiar to the enclosed metal, it is necessary to raise the temperature of the coldest part of the arc tube and increase the vapor pressure of the metal halide. Therefore, in the metal halide lamp, the tube wall load (power consumption / total inner wall area) is appropriately designed so that the desired coldest spot temperature can be obtained. Further, usually, a method of applying a heat insulating film to the outer surface of the arc tube in the vicinity of the coldest spot is adopted.

However, in these conventional metal halide lamps, when the coldest spot temperature is increased for the purpose of increasing the vapor pressure of the added metal halide and improving the color rendering, the added metal and the arc tube constituent material react rapidly, There is a problem in that the luminous flux is reduced and the arc tube is ruptured, resulting in a short life.

In the metal halide lamp, a phenomenon called arc color separation is known. This is a phenomenon in which the arc temperature is not uniform over the entire arc, and the excited state of atoms and the luminescent atomic species differ because the arc temperature varies depending on the arc site, and as a result, the emission spectrum and color vary depending on the location of the arc. is there. The temperature of the arc is highest on the center axis of the arc connecting the electrodes,
The arc temperature becomes lower as going from the center of the arc toward the inner wall of the arc tube to the periphery of the arc. Therefore, for example, in a metal halide lamp containing rare earth iodides DyI ₃ , NdI ₃ , and CsI as a fill material, the emission of mercury, Dy, and Nd neutral atoms and ions, which have large excitation energy, is dominant in the high-temperature portion of the arc center. Dy and Nd neutral atoms mainly emit light in the surrounding temperature region, and Cs and DyI molecules emit light in a relatively low temperature portion outside the arc.

When such a metal halide lamp is combined so that the arc axis is located on the optical axis of the concave reflecting mirror 5 as shown in FIG. 2, the illumination optical device is constructed. The color reflects the color distribution of the arc. That is, the center of the light receiving surface corresponds to the center axis of the arc of the metal halide lamp light source, and the periphery of the light receiving surface corresponds to the periphery of the arc. The color distribution and spectrum distribution of the arc from the center axis of the arc toward the periphery of the arc correspond to the color distribution of the light receiving surface from the center of the light receiving surface to the periphery. Therefore, when the above-described arc color separation phenomenon occurs in the metal halide lamp light source, the light receiving surface has a large spectral distribution, that is, a color that is greatly different between the center and the periphery, resulting in remarkable color unevenness. DyI _3, NdI ₃ described above,
When an illumination optical system is configured by using a metal halide lamp containing CsI as a light source, the center of the light receiving surface of the image display device is greenish and has a high color temperature, while the periphery of the light receiving surface is reddish and the color temperature is low. .

Conventionally, to solve this problem, the outer surface of the metal halide lamp arc tube is processed into a semitransparent state (frosted glass) by a sandblast method or the like (hereinafter referred to as frost processing) to improve the nonuniformity of the arc color. The method is known. However, if the outer surface of the lamp is frosted in an optical system in which the light emitted from the lamp is condensed by a concave reflecting mirror, the size of the apparent light source increases, and the efficiency of light collection decreases. . As a result, even if the color unevenness on the light-receiving surface is improved, the brightness on the light-receiving surface is reduced.

In view of the above problems, it is an object of the present invention to provide a metal halide lamp having a long life, excellent color characteristics, high luminous efficiency, and improved arc color separation phenomenon.

[0012]

In order to solve the above problems, the present invention provides 0.4 cc or more having a pair of electrodes .
Gadolinium halide (Gd) containing at least halogen as iodine or bromine or a mixture thereof in a light-transmissive container having an internal volume of 0 cc or less, together with mercury and a rare gas for starting.
X ₃ ), lutetium halide (LuX ₃ ) and cesium halide (CsX) are encapsulated, and the gadolinium halide per unit volume of the translucent container,
The total weight of the lutetium halide and the cesium halide is more than 1 mg / cc, and the weight of the cesium halide in the total weight of the halide is 15% or more and 50% or more.
And the weight ratio of the gadolinium halide and the lutetium halide is 0.1 ≦ GdX ₃ / LuX ₃ ≦
10 and the rated lamp power is turned on at 150 W, which constitutes a metal halide lamp.

Alternatively, 0.4c with a pair of electrodes
In a transparent container having an internal volume of c or more and 2.0 cc or less , gadolinium halide (GdX ₃ ) or lutetium halide (Lu) containing at least halogen as iodine or bromine or a mixture thereof, together with mercury and a rare gas for starting.
X ₃₎ and cesium halide (CsX) is sealed, the said transparent envelope, you halogen with iodine or bromine or a mixture thereof in addition to the halide
Halogenation Tariu beam is sealed, and further, the total weight of the halides per the translucent container unit volume 1m
g / cc, and the weight of the cesium halide in the total weight of the halide is 15% or more and 50% or less.
Ri, in which the rated lamp power constitutes a metal halide lamp that will be turned by 150 W.

Alternatively, 0.4c with a pair of electrodes
Mercury in a transparent container having an internal volume of c or more and 2.0 cc or less ,
Along with the rare gas for starting, dysprosium halide (DyX ₃ ) and lutetium halide (Lu) in which at least halogen is iodine or bromine or a mixture thereof.
X ₃ ), neodymium halide (NdX ₃ ) and cesium halide (CsX) are enclosed, and further, the dysprosium halide, the lutetium halide, and the halogenation per unit volume of the light-transmissive container. neodymium, wherein the total weight of cesium halide and more than 1 mg / cc, Ri the 50% der less than 15% by weight of cesium halide in the halide total weight, the rated lamp
Power constitutes a metal halide lamp that will be turned by 150 W.

Further, the illumination optical apparatus of the present invention uses the metal halide lamp as a light source, and arranges the metal halide lamp and the concave reflecting mirror so that the arc axis of the metal halide lamp is located on the optical axis of the concave reflecting mirror. And

Further, the image display device of the present invention has the above-mentioned illumination optical device as a light source part, and is constituted by this illumination optical device and an image forming part.

[0017]

In the metal halide lamp according to the present invention, halogen is iodine or bromine or a mixture thereof,
To obtain a light source with excellent emission efficiency, emission color characteristics, and color rendering properties by appropriately setting the type, composition, and amount of metal halide in which the metal is gadolinium, lutetium, dysprosium, neodymium, thallium, or cesium. You can Further, the reaction between the arc tube constituent material and the added metal is less likely to proceed, and a longer life can be realized. Further, the color separation of the arc can be greatly improved as compared with the conventional one, and when the metal halide lamp of the present invention is used as the light source of the illumination optical device, the color unevenness on the light receiving surface can be remarkably reduced.

The reason why the color separation of the arc is improved by the present invention will be described below.

As described above, the color separation of the arc occurs in the metal halide lamp because the arc temperature is different in each part of the arc, and mainly the emitting atomic species are different. Further, even with respect to one luminescent atomic species, if the temperature is different, the excited level is different, so that the emission wavelength changes with the temperature. Generally, when the arc temperature is high, the emission intensity of light having a wavelength in the blue region where the excitation energy is large, and when the arc temperature is low, the emission intensity of light having a wavelength in the red region where the excitation energy is relatively low increases. When dysprosium iodide is used as the enclosure, the DyI molecule emits light particularly in the low temperature area around the arc, and the degree of arc color separation is further increased. Therefore, in order to improve the arc color separation of a metal halide lamp, it is necessary to make the arc temperature uniform and to select a substance that emits light of the same wavelength even at different arc temperatures. However, it is actually extremely difficult to make the arc temperature uniform throughout the lamp arc tube.

On the other hand, lutetium, which is the enclosure according to the present invention, has a substantially constant emission spectrum even at various arc temperatures, and emits almost the same light emission at a high temperature portion on the central axis of the arc and a low temperature portion around the arc. Therefore, the color separation of the arc is extremely small. Such characteristics of lutetium are considered to be due to the fact that the energy of the excitation level involved in light emission does not change much depending on the emission wavelength.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

The structure is the same as that of FIG. 1 described in the above-mentioned conventional example except for the enclosed material, and the description thereof will be omitted. (Example 1) The arc tube light emitting part 1 has a substantially spheroidal shape, a central maximum inner diameter of 8.0 mm, and an internal volume of 0.5 cc. The distance between the electrodes, that is, the arc length is 6.0 mm. GdI ₃ was 0.5 mg and LuI ₃ was 0.
2 mg, 0.3 mg of CsI, 10.0 mg of mercury as a buffer gas, and 200 Torr of Ar as a rare gas for starting are enclosed.

The metal halide lamp having the above structure was incorporated in the image display device shown in FIG. 2 to evaluate the emission spectrum. The liquid crystal shutter 11 driven by the video signal is shown by a dotted line. Lamp power 150
The lamp was lit at W, a lamp voltage of 90 V, and a lamp current of 1.7 A.

Here, 5 is a concave reflecting mirror whose reflecting surface is a parabolic surface or an elliptical surface, 6 is a light receiving surface, and 7 is a projection lens system. The spectral distribution at the center of the light receiving surface 6 is shown by the curve 1 (solid line) in FIG. Curve 2 (dashed line) shows the spectral distribution when the inclusion was DyI ₃ -TlI-CsI for comparison.

That is, in FIG. 3, a curve 1 is a lamp according to this embodiment, and a curve 2 is a DyI prepared for comparison.
It is an emission spectrum of a _3- TlI-CsI system lamp.
All two lamps were identical except for the metal halide fill. When curve 1 and curve 2 are compared, GdI
It can be seen that in the lamp of the present invention in which a predetermined amount of ₃ , LuI ₃ , and CsI is encapsulated, abundant light emission specific to the encapsulated metal is obtained over the entire visible range, and the color rendering property is significantly improved. Since the metal halide lamp according to the present invention has an emission spectrum distributed in the entire visible region, when used as a light source for an OHP or a projection type liquid crystal display, the screen has excellent brightness and color characteristics as compared with a conventional metal halide lamp. Become. Further, since the lamp according to the present invention does not contain DyI ₃ as a main component, Dy is not contained in the peripheral portion of the arc.
There is no reddish emission region that seems to be the molecular emission of I.
Therefore, the color uniformity of the screen is also greatly improved.

By the way, in the metal halide lamp having the above structure, the total weight of gadolinium iodide, lutetium iodide, and cesium iodide enclosed is 1 mg / volume of the arc tube.
Although it is larger than cc, the reason for doing so is as follows. During the operation of the lamp, most of the iodide is a liquid and exists near the coldest point, and a part of the iodide is evaporated and exists in the discharge space as a gas. Considering the case where the total weight of iodide is increased, excess liquid iodide is present, and a part of the liquid iodide comes into contact with the inner wall of the inner surface of the lamp having a temperature higher than the coldest point. Then, even at that place, the liquid evaporates, and the vapor pressure of iodide rises higher than that before the increase of iodide. As a result, the light emission intensity of the metal is increased and the color rendering is improved. As a result of conducting experiments with variously encapsulated amounts varied, it was found that if the total encapsulated weight of GdI ₃ , LuI ₃ , and CsI was greater than 1 mg / cc, there was no practical problem in color rendering. However, for the rated lamp power of 150 W, the internal volume of the lamp is 0.4 cc or more and 2.0
It must be cc or less. When the internal volume is less than 0.4 cc, when the lamp is turned on, liquid iodide adheres to the entire inner surface of the lamp, resulting in a significant decrease in brightness. The internal volume is 2.
When it is larger than 0 cc, the area of the coldest spot becomes large, so that iodide must be further increased.

The weight ratio of GdI ₃ / LuI ₃ is 0.1.
It was found that if it is less than the above range, the brightness of the light emitting arc is lowered and the efficiency is lowered, which is not preferable. Also GdI ₃ / Lu
When the weight ratio of I ₃ exceeds 10, the continuous emission intensity decreases in the emission spectrum distribution, and conversely, the emission intensity of mercury increases and the color rendering property deteriorates.

On the other hand, among the enclosed iodides, cesium iodide has the function of stabilizing the arc and the effect of increasing the vapor pressures of GdI ₃ and LuI ₃ . That is, the arc is stabilized by enclosing cesium iodide and at the same time GdC
A desired emission spectrum can be obtained by forming a complex iodide having a high vapor pressure such as sI ₄ . But CsI
When a large amount of iodide is enclosed, iodide adheres to the inner surface of the arc tube and causes a decrease in brightness. From the experimental results, it is practically desirable that the content of cesium iodide is 15% or more and 50% or less with respect to the weight of all iodides.

From the life evaluation result, it was confirmed from the life evaluation result that the metal halide lamp according to the present invention had no damage or leak and had a small degree of devitrification. (Second Embodiment) Next, a metal halide lamp according to a second embodiment will be described. It should be noted that the configuration is the same as that of FIG. 1 described in the above-mentioned conventional example except for the inclusions, and the description thereof is omitted.

The arc tube light-emitting portion 1 has a substantially spheroidal shape and has a central maximum inner diameter of 8.0 mm and an internal volume of 0.5 cc.
The distance between the electrodes, that is, the arc length is 5.5 mm.
0.3 mg of GdI _{3 and} 0.2 m of LuI _{3 in the} arc tube
g, TlI of 0.1 mg, CsI of 0.3 mg, mercury as a buffer gas of 10.0 mg, and Ar as a starting rare gas of 200 Torr.

The metal halide lamp having the above structure was incorporated into the optical system shown in FIG. 2 to evaluate the emission spectrum and illuminance. Lamp power 150W, lamp voltage 90
The lamp was lit at V and a lamp current of 1.7A.

Here, 5 is a concave reflecting mirror, 6 is a light receiving surface, and 7 is
Is a projection lens system. The emission spectrum and the illuminance were measured by scanning the diagonal line of the light receiving surface. The emission spectrum was evaluated by color temperature, and the measured color temperature distribution and illuminance distribution are shown in FIG.
Is indicated by a solid line. At the same time, for comparison, DyI ₃
0.5 mg, NdI ₃ 0.2 mg, CsI 0.3
The measurement results of the lamp of the conventional encapsulated product in mg mg are also shown in a broken line in FIG.

That is, in FIG. 4, the solid line is the lamp according to the embodiment of the present invention, and the broken line is Dy prepared for comparison.
_{3 is} a color temperature distribution and an illuminance distribution of an I ₃ -NdI ₃ -CsI system lamp. Each line surrounded by a circle is based on the vertical axis in the direction of the arrow. All two lamps were identical except for the metal halide fill. As is apparent from FIG. 4, the lamp of the enclosure according to the present embodiment has almost the same brightness as the light receiving surface, that is, the illuminance and the illuminance distribution as the conventional DyI ₃ -NdI ₃ -CsI system lamp. On the other hand, regarding the color temperature of the light receiving surface, the color temperature of the lamp according to the present embodiment is slightly higher. The color temperature distribution of the light-receiving surface is largely different from the conventional enclosure and the lamp according to the present embodiment, and the difference in color temperature between the center of the light-receiving surface and the periphery of the light-receiving surface is reduced from 1400K to 300K according to the present embodiment. The color uniformity of the light receiving surface is greatly improved. This is because the inclusion of the present embodiment almost eliminates the reddish emission region that is considered to be molecular emission around the arc. Conventionally, the color distribution of the arc was a serious problem because it was reflected as color unevenness on the light receiving surface when used as a light source for OHP and liquid crystal projectors. However, the present invention can solve this problem. .

In the metal halide lamp having the above structure, the total enclosed weight of gadolinium iodide, lutetium iodide, thallium iodide, and cesium iodide must be larger than 1 mg / cc per unit volume of the arc tube for the same reason as in Example 1. There is.

As for the weight of cesium iodide, Example 1 was also used.
It was found that it is necessary to set the content to 15% or more and 50% or less with respect to the weight of the total iodide enclosed in the arc tube in the same manner as.

Next, life tests of two types of lamps, the metal halide lamp according to the present embodiment evaluated in FIG. 4 and the conventional enclosed lamp, were conducted. FIG. 5 shows the changes over time in the central illuminance maintenance rates of both when evaluated by the optical system of FIG.

The lamp according to the present embodiment shown by the solid line in the figure has a better illuminance maintenance rate, and the time for which the illuminance is 50% of the initial time is double that of the conventional enclosure (shown by the broken line), 3000.
It's time. From the results of observing the lamp, the lamp according to the present example was significantly less devitrified than the conventional encapsulated lamp, and was not damaged or leaked even after 5000 hours had passed. (Third Embodiment) Next, a metal halide lamp according to a third embodiment will be described. It should be noted that the configuration is the same as that of FIG. 1 described in the above-mentioned conventional example except for the inclusions, and the description thereof is omitted.

The arc tube light emitting part 1 has a substantially spheroidal shape and has a central maximum inner diameter of 8.0 mm and an internal volume of 0.5 cc.
The distance between the electrodes, that is, the arc length is 5.0 mm.
The arc tube DyI ₃ 0.5mg, LuI ₃ 0.5
mg, NdI ₃ 0.5 mg, CsI 0.4 mg, mercury as a buffer gas 10.0 mg, and Ar as a starting rare gas 200 Torr.

The metal halide lamp having the above-described structure is combined with the concave reflecting mirror 5 as shown in FIG. 2 to form an illumination optical device, and an image display device using this illumination optical device as a light source is formed to emit light from the lamp. The spectrum was evaluated. The emission spectrum measurement sensor was scanned from the center of the light-receiving surface toward the periphery on the diagonal line of the light-receiving surface, the spectral distribution of each part of the light-receiving surface was obtained, and the color temperature was calculated. The lamp was turned on at a power of 150 W, a lamp voltage of 90 V, and a lamp current of 1.7 A.

[0040] The color temperature distribution measurement result of the light receiving surface, DyI ₃ 0.8 mg of metal halide fill, NdI ₃ 0.
It is shown in FIG. 6 together with the measurement results when 4 mg and CsI 0.7 mg.

In FIG. 6, curve 1 is a lamp according to an embodiment of the present invention, and curve 2 is a DyI ₃ − prepared for comparison.
A color temperature distribution of the light receiving surface of the case of using NdI _3-CSI based lamps, respectively. The relative distance here is
It means the distance from the center of the light receiving surface when the distance from the center of the light receiving surface to the edge of the light receiving surface is 1. All two lamps were identical except for the metal halide fill. Comparing curve 1 and curve 2, DyI ₃ , Nd
In the conventional lamp containing I ₃ and CsI, the color temperatures of the center and the periphery of the light receiving surface are 7100K and 5600K, respectively.
And the difference is 1500K, while DyI ₃ ,
In the lamp according to the embodiment of the present invention in which a predetermined amount of LuI ₃ , NdI ₃ and CsI is enclosed, the color temperature at the center of the light receiving surface is 6500K, the color temperature at the periphery is 6200K, and the difference is 3
It can be seen that the uniformity of the color temperature distribution is greatly improved to 00K. The brightness of the light-receiving surface was exactly the same in both the center and the periphery.

Further, according to the example of the present invention, the reddish light emitting region, which was considered to be the molecular emission of DyI, which was conventionally emitted in the low temperature portion around the arc, was eliminated, and the emission which was thought to be lutetium was observed instead. Lutetium emitted almost the same color near and around the center of the arc.

Also in the enclosure of this example, Examples 1 and 2
Similarly, it was found that if the total weight of DyI ₃ , LuI ₃ , NdI ₃ , and CsI enclosed was greater than 1 mg / cc, there would be no practical problem. However, rated lamp power 150W
On the other hand, the internal volume of the lamp needs to be 0.4 cc or more and 2.0 cc or less. When the internal volume is less than 0.4 cc, when the lamp is turned on, liquid iodide adheres to the entire inner surface of the lamp, resulting in a significant decrease in brightness. When the inner volume is larger than 2.0 cc, the area of the coldest spot becomes large, so that iodide must be further increased.

It has also been found that the weight of cesium iodide needs to be 15% or more and 50% or less with respect to the weight of all iodides enclosed in the arc tube, as in Examples 1 and 2.

Regarding the service life, it was confirmed from the service life evaluation results that the metal halide lamps of the examples of the present invention did not suffer damage or leak even after 3000 hours had passed, and the degree of devitrification was less than that of the conventional filled material.

Further, based on the above-mentioned embodiment, it was found that the effect of the present invention was conspicuously exhibited when the lamp power was tested in the following range. That is, the lamp power per distance between the electrodes is set to 20 W / mm or more. If the lamp power per distance between the electrodes is less than 20 W / mm, the coldest spot temperature of the lamp is lowered, and it becomes impossible to obtain a sufficient vapor pressure of the metal halide. On the contrary, 6
When it is higher than 0 W / mm, the lamp temperature rises excessively and the lamp life is shortened.

In each of the above examples, iodide was used as the enclosed halide, but it was confirmed that the effect of the present invention can be obtained even if bromide or iodide and bromide are mixed.

Further, in each of the above embodiments, the effect of the present invention is shown for the metal halide lamp having the single tube structure without the outer tube. However, the effect of the present invention is not limited to the single tube structure, and the structure with the outer tube is provided. It is also confirmed in the metal halide lamp of.

[0049]

As is apparent from the above description, the present invention can provide a light source having excellent luminous efficiency, luminous color characteristics, and color rendering properties. Further, the reaction between the arc tube constituent material and the added metal is less likely to proceed, and a longer life can be realized. Further, the color separation of the arc can be greatly improved as compared with the conventional one, and when the metal halide lamp of the present invention is used as the light source of the illumination optical device, the color unevenness on the light receiving surface can be remarkably reduced.

Further, the illumination optical device and the image display device of the present invention can obtain a light receiving surface which is bright for a long time, has excellent color characteristics, and has high color uniformity.

[Brief description of drawings]

FIG. 1 is a sectional side view of a metal halide lamp arc tube according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an image display device including the illumination optical device according to the first embodiment of the present invention as a light source unit.

FIG. 3 is a graph showing an emission spectrum of a metal halide lamp according to a conventional example and Example 1 of the present invention.

FIG. 4 is a graph showing a color temperature and an illuminance distribution on a light receiving surface of Example 2 of the present invention.

FIG. 5 is a graph showing the life characteristic evaluation results of the lamp of Example 2 of the present invention.

FIG. 6 is a color temperature distribution characteristic diagram of a light receiving surface of a lamp according to a third embodiment of the present invention.

[Explanation of symbols]

1 Quartz glass arc tube luminous part 2 Tungsten electrode 3 Sealing part 4 External lead wire 5 concave reflector 6 Light receiving surface 7 Projection lens system

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayuki Wakamiya 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-3-219546 (JP, A) JP-A-5- 135739 (JP, A) JP-A-56-50048 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01J 61/20

Claims (5)

(57) [Claims] 1. 0.4 cc or more with a pair of electrodes
In a light- transmissive container having an internal volume of 2.0 cc or less , gadolinium halide (GdX ₃ ), lutetium halide (LuX ₃ ) The cesium halide (CsX) is encapsulated, and the above-mentioned gadolinium halide per unit volume of the translucent container
System, said lutetium halide, said cesium halide
The total weight of the system is more than 1 mg / cc, and the halide
The weight of said cesium halide in the total weight is 15% or more.
50% or less, the gadolinium halide and the
The weight ratio of lutetium halide is 0.1 ≦ GdX ₃ / L
A metal halide lamp characterized in that uX ₃ ≦ 10 and the rated lamp power is turned on at 150 W. 2. 0.4 cc or more equipped with a pair of electrodes
In a translucent container having an internal volume of 2.0 cc or less , gadolinium halide (Gd) containing iodine or bromine or a mixture thereof with mercury and a rare gas for starting is used.
X _3), it is sealed halogenated lutetium (LUX ₃₎ and cesium halide (CsX) is, wherein the transparent envelope, the addition to the halides, bromine or iodine or mixtures thereof and be Ruha halogenated Tariu-time
There is enclosed, the total weight of the halides per translucent container unit volume
Is more than 1 mg / cc, and the total weight of its halides
The weight of said cesium halide is 15% or more and 50% or more.
The metal halide lamp is as follows, which is lit at a rated lamp power of 150 W. 3. 0.4 cc or more equipped with a pair of electrodes
2.0cc following mercury transparent envelope having an inner volume, with the starting rare gas, halides of dysprosium (dyx ₃₎ to at least a halogen is iodine or bromine or a mixture thereof, halogenated lutetium (LUX ₃₎ , Neodymium halide (NdX ₃ ) and cesium halide (CsX) are enclosed, and the lamp power per distance between electrodes is 20 W / mm or more.
The halogenated volume per unit volume of the transparent container.
Dysprosium, said lutetium halide, said halo
The total weight of neodymium genide and the cesium halide is 1
more than mg / cc, said halo in the total weight of halide
A metal halide lamp, wherein the weight of cesium genide is 15% or more and 50% or less, and the rated lamp power is turned on at 150W . 4. A metal halide lamp as a light source,
And a concave reflector, wherein the illumination optical apparatus arc axis is positioned on the optical axis of the concave reflector of a metal halide lamp, according to claim 1-3 to said metal halide lamp
An illuminating optical device characterized by using any one of the above metal halide lamps. 5. An image display device, comprising: the illumination optical device according to claim 4 ; and an image forming unit that forms an image using the illumination optical device as a light source unit.