JP3239621B2 - Metal halide lamp and illumination optical 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 for general illumination and optical equipment, and an illumination optical device combining a metal halide lamp and a concave reflecting mirror.

[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 their demand has been expanding as automotive lighting or optical equipment light source. Hereinafter, an example of the above-described metal halide lamp will be described with reference to the drawings.

FIG. 6 is a diagram showing a configuration of a single tube type metal halide lamp. In FIG. 6, reference numeral 61 denotes a light emitting portion made of a quartz glass arc tube, 62 denotes a tungsten electrode provided via a molybdenum foil, 63 denotes a sealing portion in which the molybdenum foil is hermetically sealed, and 64 denotes an external lead wire. The operation of the metal halide lamp configured as described above will be described below.

In a metal halide lamp, a metal halide added together with mercury and a rare gas is present as a liquid near the arc tube wall during operation, while a partially evaporated metal halide vapor forms a metal atom at the center of the arc. Dissociated into halogen atoms, the metal vapor is excited by an arc and emits a spectrum unique to the metal. For this reason, metal halide lamps have the advantage of being superior in luminous efficiency and color rendering to high-pressure mercury lamps. Many Dy-Nd-Cs-based metal halide lamps (JP-A-3-219546) have been put into practical use as metal iodides.

[0005]

Generally, in this type of metal halide lamp, the luminous characteristics of the lamp are determined by the vapor pressure of the enclosed metal halide. That is,
In order to obtain an emission spectrum peculiar to the encapsulated metal, it is necessary to raise the temperature of the coldest part of the arc tube to increase the vapor pressure of the metal halide. Therefore, in the metal halide lamp, the tube wall load is appropriately designed so as to obtain a desired cold spot temperature. Further, usually, a method of applying a heat insulating film to the outer surface near the coldest point of the arc tube has been adopted.

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

In a projection type liquid crystal display, a method of once separating light emitted from a light source into R (red), (green), and B (blue), adjusting white balance, and adjusting three colors again. Is adopted. Therefore, when the metal halide lamp is used as a light source for a projection display, the light emission spectrum of the light source is meaningless unless the RGB is balanced.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a metal halide lamp whose emission spectrum is well distributed in RGB in the visible region, has excellent color rendering properties, and has a long life.

[0009]

In order to achieve the above object, a metal halide lamp according to the present invention has at least a halogen containing iodine or bromine or a halogen thereof together with mercury and a starting rare gas in a translucent container having a pair of electrodes. halogenated holmium to mixture (Hox ₃₎ and halogenated Purazeojimu a structure encapsulating (PrX _3).

[0010] Alternatively, the mercury in the translucent container provided with the pair of electrodes, together with the starting rare gas, halides terbium be at least a halogen iodine or bromine or their mixture (TbX ₃₎ and halogenated Purazeojimu (PRx ₃ ) Is enclosed.

Alternatively, holmium halide (HoX ₃ ) and thulium halide (Tm) containing at least halogen as iodine or bromine or a mixture thereof together with mercury and a starting rare gas in a light-transmitting container provided with a pair of electrodes.
X ₃ ).

Alternatively, terbium halide (TbX ₃ ) and thulium halide (Tm) containing at least halogen as iodine or bromine or a mixture thereof together with mercury and a starting rare gas in a light-transmitting container provided with a pair of electrodes.
X ₃ ).

Alternatively, dysprosium halide (DyX ₃ ) and tin halide (in which at least halogen is iodine or bromine or a mixture thereof) together with mercury and a rare gas for starting are placed in a light-transmitting container provided with a pair of electrodes. SnX ₂ ) is enclosed.

Alternatively, holmium halide (HoX ₃ ) and tin halide (Sn) containing at least halogen as iodine or bromine or a mixture thereof together with mercury and a rare gas for starting are placed in a light-transmitting container provided with a pair of electrodes.
X ₂ ).

Alternatively, terbium halide (TbX ₃ ) and tin halide (Sn) containing at least halogen as iodine or bromine or a mixture thereof together with mercury and a rare gas for starting are placed in a light-transmitting container provided with a pair of electrodes.
X ₂ ).

Further, in the above structure, it is preferable that the total weight of the halide per unit volume of the translucent container is more than 1 mg / cc.

Further, the illumination optical device of the present invention uses the above-mentioned metal halide lamp as a light source, and comprises the metal halide lamp and a concave reflecting mirror whose reflecting surface is a paraboloid or an elliptical surface, wherein the arc axis of the metal halide lamp is a concave. It is configured to be located on the optical axis of the reflecting mirror.

Further, the image display device of the present invention has a configuration in which the above-mentioned illumination optical device is used as a light source unit and this illumination optical device and an image forming unit.

[0019]

According to the present invention, at least holmium halide and praseodymium halide, terbium halide and praseodymium halide, or holmium halide and thulium halide, or terbium halide and thulium halide, or halogen By adding dysprosium halide and tin halide, or holmium halide and tin halide, or terbium halide and tin halide, and by appropriately setting the amount of encapsulation,
A light source having an emission spectrum with an appropriate balance in the visible RGB region and having excellent color rendering properties can be obtained. Also, the reaction between the arc tube constituent material and the added metal hardly progresses,
Long life can be realized.

[0020]

【Example】

(Embodiment 1) A metal halide lamp according to an embodiment of the present invention will be described below. FIG. 1 is a diagram showing a metal halide lamp arc tube according to a first embodiment of the present invention.

The structure of the single-tube quartz glass metal halide lamp arc tube shown in FIG. 1 is substantially the same as that of FIG. 6, wherein 1 is a quartz glass arc tube light emitting portion, 2 is a tungsten electrode, and 3 is molybdenum. A sealing part in which the foil is hermetically sealed,
4 is an external lead wire. Reference numeral 5 denotes a specific halide-containing arc tube internal space (hereinafter, referred to as an arc tube) containing a specific halide not present in the conventional structure.

The arc tube light emitting section 1 has a substantially spheroidal shape, the central portion has a maximum inner diameter of 8.0 mm, and an inner volume of 0.5 cc.
The distance between the electrodes, that is, the arc length is 6.0 mm.
In the arc tube 5, 0.5 mg of HoI _{3 and} 0.5 mg of PrI ₃
mg, CsI 0.2 mg, mercury 10.0 mg as a buffer gas, and 150 Torr Ar as a starting rare gas. The metal halide lamp having the above configuration was incorporated in the optical system shown in FIG. 2 and the emission spectrum was evaluated. Lamp power 150W, lamp voltage 90
V and the lamp current was 1.7 A.

In FIG. 2, reference numeral 6 denotes a metal halide lamp, 7 denotes a condenser mirror, 8 denotes a projection lens system, and 9 denotes a light receiving surface. FIG. 3 shows the spectral distribution at the center of the light receiving surface of this embodiment, and FIG. 4 shows a conventional case where the enclosure is DyI ₃ -NdI ₃ -CsI.
It was shown to. That is, FIG. 3 shows the emission spectrum of the lamp according to the present embodiment, and FIG. 4 shows DyI ₃ prepared for comparison.
-NDI ₃ the emission spectrum of -CsI system lamps.

The two lamps were all identical except for the fill. Comparing curves 1 and 2, HoI ₃ ,
PrI _3, the lamp of the present embodiment by a predetermined amount encapsulate CsI is DyI _3, NdI _3, the lamp as well as a good balance rich encapsulated metal-specific over RGB visible region light emitting by a predetermined amount enclosing CsI is obtained You can see that there is.

The metal halide lamp according to this embodiment is
Since good balance emission spectrum of RGB visible region is distributed, when used as a light source for OHP or projection type liquid crystal display, a conventional DyI _3, NdI _3, as with CsI based metal halide lamp, the brightness of the screen ,
The color also has excellent characteristics. Further, since the lamp according to the present embodiment does not contain DyI ₃ as a main component, there is no reddish light emitting region that is considered to be molecular light emission of DyI at the periphery of the arc. Therefore, the color uniformity of the screen is also greatly improved.

FIG. 5 shows the relationship between the lamp lighting time and the center illuminance maintenance rate. (A) is a lamp according to the embodiment, (b) is a DyI ₃ -NdI ₃ -CsI system lamps. Since the lamp of the present embodiment does not contain NdI ₃ having high reactivity with glass as a main component, crystallization of quartz glass is suppressed, so that the lamp life is about 1.5 times that of the conventional lamp.
Doubled.

By the way, in the metal halide lamp having the above structure, the total weight of holmium iodide, praseodymium iodide and cesium iodide was 1 mg / volume per volume in the arc tube.
The reason why the number is larger than cc is as follows. Most of the iodide is a liquid during the lamp operation and exists near the coldest point, and a part of the iodide evaporates and exists as a gas in the discharge space. Here, considering the case where the total weight of the iodide is increased, the liquid iodide is excessively present, and a part thereof comes into contact with the inner wall having a temperature higher than the coldest point on the inner surface of the lamp. Then, the liquid evaporates also in that place, and the vapor pressure of the iodide increases from the state before the increase in the iodide. As a result, the luminous intensity of the metal increases, and the color rendering properties improve. As a result of conducting experiments with various amounts of encapsulation, HoI
It has been found that there is no practical problem if the total weight of ₃ , ₃ , PrI ₃ and CsI is 1 mg / cc or more.

On the other hand, among the encapsulated iodides, cesium iodide has a function of stabilizing the arc and needs to be enclosed. However, the vapor pressure of HoI ₃ and PrI ₃ decreases. That is, the arc is stabilized by encapsulating cesium iodide, but at the same time, a stable composite iodide such as HoCsI ₄ is formed, and a desired emission spectrum cannot be obtained. Therefore, when a large amount of CsI is sealed, the brightness is reduced. From the experimental results, it is practically desirable that cesium iodide be 30% or less based on the weight of all iodides.

(Embodiment 2) Embodiment 2 of the present invention will be described below. As in the case of the first embodiment shown in FIG.
It is. The distance between the electrodes, that is, the arc length is 6.0 mm. The arc tube TbI ₃ 0.5mg, PrI ₃ is 0.5 mg, CsI is 0.2 mg, further mercury 10.0mg as a buffer gas, Ar as starting rare gas 15
0 torr is enclosed.

The metal halide lamp having the above configuration was incorporated in the optical system shown in FIG. 2 and the emission spectrum was evaluated in the same manner as in Example 1. As a result, in this example, a good emission spectrum was obtained as in Example 1, and the color uniformity of the screen was also improved. It was also confirmed that the service life was 3500 hours or more. As in Example 1, it was confirmed that it is desirable that the total weight of the inclusions be 1 mg / cc or more, of which CsI is 30% or less.

Embodiment 3 Hereinafter, Embodiment 3 of the present invention will be described. As in the case of the first embodiment shown in FIG.
It is. The distance between the electrodes, that is, the arc length is 6.0 mm. In the arc tube, 0.5 mg of HoI ₃ , 0.5 mg of TmI ₃ , 0.2 mg of CsI, 10.0 mg of mercury as a buffer gas, and 15 mg of Ar as a starting rare gas were used.
0 torr is enclosed.

The metal halide lamp having the above configuration was incorporated in the optical system shown in FIG. 2 and the emission spectrum was evaluated in the same manner as in Example 1. As a result, in the case of this lamp, the same good emission spectrum was obtained as in the case of Example 1.
It was also confirmed that the service life was 3500 hours or more. The total weight of the inclusions was 1 mg / c as in Example 1.
It has been confirmed that it is desirable to set CsI to 30% or less, of which c is not less than c.

(Embodiment 4) Hereinafter, Embodiment 4 of the present invention will be described. As in the case of the first embodiment shown in FIG.
c. The distance between the electrodes, that is, the arc length is 6.0 m.
m. 0.5 mg of TbI ₃ and TmI in the arc tube
₃ 0.5 mg, CsI is 0.2 mg, mercury as further buffer gas 10.0 mg, Ar is 150 Torr sealed as starting rare gas.

The light emission spectrum was evaluated in the same manner as in Example 1 by incorporating the metal halide lamp having the above structure into the optical system shown in FIG. As a result, a good emission spectrum was obtained in the case of the lamp of this embodiment as in the case of Embodiment 1. It was also confirmed that the service life was 3500 hours or more. As in Example 1, the total weight of the
It was confirmed that it is desirable that the content be not less than mg / cc, and that the content of CsI be not more than 30%.

(Embodiment 5) Hereinafter, Embodiment 5 of the present invention will be described. Similar to the first embodiment of FIG. 1, it has a substantially spheroidal shape, a central maximum inner diameter of 12.0 mm and an internal volume of 1.0.
An experiment was performed using a cc metal halide lamp. The distance between the electrodes was 6.0 mm, and the amount enclosed in the arc tube was DyBr ₃
Was 1.0 mg, SnBr ₂ was 1.0 mg, CsBr was 0.4 mg, mercury was 20 mg, and Ar was 200 torr.

The metal halide lamp having the above configuration is incorporated in the optical system shown in FIG.
W, lamp voltage 90V, lamp current 2.7A,
Evaluation was performed in the same manner as in Example 1. As a result, in the case of this lamp, the same good emission spectrum was obtained as in the case of Example 1. It was also confirmed that the service life was 3500 hours or more. As in Example 1, D
yBr ₃ , SnBr ₂ , CsBr in a total weight of 1 mg / cc
As described above, it was confirmed that it is desirable that CsBr be 30% or less.

(Embodiment 6) Hereinafter, Embodiment 6 of the present invention will be described. Similar to the first embodiment of FIG. 1, it has a substantially spheroidal shape, a central maximum inner diameter of 12.0 mm and an internal volume of 1.0.
An experiment was performed using a cc metal halide lamp. The distance between the electrodes was 6.0 mm, and the amount enclosed in the arc tube was HoBr ₃
Was 1.0 mg, SnBr ₂ was 1.0 mg, CsBr was 0.4 mg, mercury was 20 mg, and Ar was 200 torr.

The metal halide lamp having the above configuration is incorporated in the optical system shown in FIG.
W, lamp voltage 90V, lamp current 2.7A,
Evaluation was performed in the same manner as in Example 1. As a result, a good emission spectrum was obtained in the case of the lamp of this embodiment as in the case of Embodiment 1. Similarly, in the present embodiment, the life is 3
It was confirmed that it was 500 hours or more. As in the case of Example 1, it was confirmed that it is desirable that the total weight of HoBr ₃ , SnBr ₂ , and CsBr should be 1 mg / cc or more, of which CsBr should be 30% or less.

(Embodiment 7) Hereinafter, Embodiment 7 of the present invention will be described. Similar to the first embodiment of FIG. 1, it has a substantially spheroidal shape, a central maximum inner diameter of 12.0 mm and an internal volume of 1.0.
An experiment was performed using a cc metal halide lamp. The distance between the electrodes was 6.0 mm, and the amount enclosed in the arc tube was TbBr ₃
Was 1.0 mg, SnBr ₂ was 1.0 mg, CsBr was 0.4 mg, mercury was 20 mg, and Ar was 200 torr.

The metal halide lamp having the above configuration is incorporated in the optical system shown in FIG.
W, lamp voltage 90V, lamp current 2.7A,
Evaluation was performed in the same manner as in Example 1. As a result, in the case of this lamp, the same good emission spectrum was obtained as in the case of Example 1. It was also confirmed that the service life was 3500 hours or more. As in Example 1, T
bBr ₃ , SnBr ₂ , CsBr in a total weight of 1 mg / cc
As described above, it was confirmed that it is desirable that CsBr be 30% or less.

In Examples 1-4, iodide was used as the halide to be encapsulated. However, it was confirmed that the effect of the present invention can be obtained with bromide or a mixture of iodide and bromide. Was.

In Examples 5 to 7 above, bromide was used as the halide to be encapsulated. However, it was confirmed that the effects of the present invention can be obtained with iodide or a mixture of iodide and bromide. Was.

In the above embodiment, the effect of the present invention was shown for a metal halide lamp having a single tube structure without an outer tube. However, the effect of the present invention is not limited to the single tube structure, but is applicable to a structure having an outer tube. It has also been confirmed in metal halide lamps.

[0044]

As described above, according to the metal halide lamp of the present invention, at least a holmium halide and a praseodymium halide, or a halogenated praseodymium halide or a rare gas for starting are placed in a light-transmitting container provided with a pair of electrodes. Terbium and praseodymium halide, or holmium and thulium halide, or terbium and thulium halide, or dysprosium and tin halide, or holmium and tin halide, or terbium and halogen By adding tin oxide and setting the amount of tin oxide appropriately, it is possible to obtain a light source having an emission spectrum with an appropriate balance in the visible RGB region and having excellent color rendering properties. In addition, the reaction between the arc tube constituent material and the additional metal hardly progresses, and a longer life can be realized.

Further, the illumination optical device and the image display device of the present invention use the above-mentioned metal halide lamp as a light source, and include the metal halide lamp and a concave reflecting mirror having a paraboloidal or elliptical reflecting surface. With a configuration in which the arc axis is located on the optical axis of the concave reflecting mirror, a longer life can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a metal halide lamp arc tube according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an optical system used for emission spectrum evaluation.

FIG. 3 is an emission spectrum diagram of the metal halide lamp according to Example 1 of the present invention.

FIG. 4 is an emission spectrum diagram of a metal halide lamp according to a conventional example.

FIG. 5 is a diagram showing the life of a metal halide lamp according to a conventional example and Example 1 of the present invention.

FIG. 6 is a diagram showing a conventional metal halide lamp arc tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Quartz glass light emitting tube light emitting part 2 Tungsten electrode 3 Molybdenum foil sealing part 4 External lead wire 5 Specific halide containing arc tube inner space 6 Metal halide lamp 7 Condensing mirror 8 Projection lens 9 Light receiving surface

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-53-94466 (JP, A) JP-A-2-5357 (JP, A) JP-A-2-7347 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) H01J 61/20 H01J 61/88

Claims (5)

(57) [Claims] In a light-transmitting container provided with a pair of electrodes, at least a halogen (X) is added together with mercury and a starting rare gas.
Terbium halide (TbX ₃ ) and thulium halide (T
mX ₃ ) is a metal halide lamp. 2. A mercury and a starting rare gas together with at least a halogen (X) in a translucent container having a pair of electrodes.
Terbium halide (TbX ₃ ) and tin halide (Sn
A metal halide lamp characterized by enclosing X ₂ ). 3. A metal halide lamp according to claim 1 or 2, characterized in that the total weight of halides per translucent container unit volume was more than 1 mg / cc. 4. A light source of a metal halide lamp and the metal halide lamp are arranged in combination, and a reflection surface of the light source comprises a concave reflecting mirror having a parabolic surface or an elliptical surface.
The metal halide lamp is an illumination optical device in which an arc axis is positioned on an optical axis of a concave reflecting mirror, and uses the metal halide lamp according to any one of claims 1 to 3 as the light source. Optical device. 5. An image display device comprising at least a light source unit including a light source and a light condensing unit, and an image forming unit.
An image display device, wherein the illumination optical device according to claim 4 is used for the light source unit.