JPH11111219A - Short arc type metal halide discharge lamp, metal halide discharge lamp device, and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a short arc type metal halide discharge lamp whose starting characteristics is good and an irradiating surface can be higher essentially without using mercury light rising characteristics when starting up and environmental load is large as well as lighting adjustment can be performed, a restarting voltage is low, and that has an airtight container that is hardly bursts, a metal halide discharge lamp device using this, and a lighting system. SOLUTION: This is provided with an airtight container 1, electrodes 2, sealed metallic foils 3, and outer leads 4. The airtight container 1 is formed by forming vitreous silica into a spheroidal shape with an inner diameter of 14 mm, and is integrally provided with a pair of long and narrow sealing parts 1a, 1a at both ends in the major axial direction of the oval. A noble gas, a first halide, a second halide is sealed in the airtight container 1 as a discharge medium. Argon 500 Torr is sealed in as the noble gas. Sodium iodide of 1.3 mg is sealed in as the first halide. FeI of 8 mm is sealed in as the second halide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a short arc type metal halide discharge lamp, a metal halide discharge lamp device using the same, and a lighting device.

[0002]

2. Description of the Related Art Metal halide discharge lamps in which a rare gas, a luminescent metal halide and mercury are sealed in an arc tube having a pair of electrodes opposed to each other are widely used because of their relatively high efficiency and high color rendering properties. Have been.

In a liquid crystal projector or the like that condenses the light emitted from the lamp and projects it on a screen, a small, short arc type metal halide discharge lamp is used. Recently, small and short-arc metal halide discharge lamps have been used as headlights for automobiles.

[0004]

In the case of a small and short arc metal halide discharge lamp, the shorter the distance between the electrodes, the higher the vapor pressure of mercury in order to secure a required lamp voltage. That is, the metal halide discharge lamp is filled with mercury in order to maintain required electric characteristics. For example, in a small, short arc metal halide discharge lamp having an arc tube of 1 cc or less, the mercury vapor pressure during operation becomes as high as 20 atm or more. Therefore, there are the following disadvantages.

[0005] The first problem is that when the temperature of the arc tube changes, the color temperature of light emission greatly changes, and accordingly, the color rendering properties also change. This will be described below with reference to FIG. FIG. 11 is a graph showing the emission spectrum distribution of a conventional short arc type metal halide discharge lamp.

In the figure, the horizontal axis represents wavelength (nm) and the vertical axis represents relative radiation power (%).

[0007] This conventional discharge lamp comprises 500 torr of argon as a rare gas, 1 mg of dysprosium iodide DyI3 as a halide, and neodymium Nd iodide Nd.
It contains 1 mg of I3 and 13 mg of mercury.

[0008] The emission spectrum is composed of continuous emission by dysprosium and neodymium and main emission line spectra by the elements each having a symbol on the arrow, and it can be seen that the emission line spectrum by mercury has a large power.

[0009] The amount of light emitted by the luminescent metal changes in proportion to its vapor pressure. Since the vapor pressure of the luminescent metal is significantly lower than that of mercury, when the temperature of the luminous tube changes, the luminous metal changes its vaporization amount and its vapor pressure, so that the luminescence amount changes.

On the other hand, since the vapor pressure of mercury is very high and does not change so much even if the temperature of the arc tube changes, the amount of luminescence of mercury by the strong emission line spectrum changes little. Therefore, when the input power to the arc tube decreases, the emission of light by mercury becomes relatively dominant, so that the color temperature of the emission decreases and the color rendering property decreases. This means that conventional metal halide discharge lamps containing mercury are not suitable for dimming.

The second problem is that since the mercury vapor pressure during lighting is very high, a restart voltage that is very high and has a large power is required for restarting. This not only makes the lighting circuit expensive, but also makes it necessary to insulate the circuit, the lamp and the equipment containing them from high voltages.

A third problem is that the arc tube tends to burst. As described above, since the vapor pressure at the time of lighting of mercury is high, the initial strain or the strain increases during long-term lighting, so that the arc tube tends to burst.

In addition to the above-mentioned problems associated with the high vapor pressure of mercury, there is also the problem of enclosing mercury. That is, since mercury has a large environmental load, it is convenient if it is not necessary to use it.

The fourth problem is that the light output characteristics from the start are poor because mercury is sealed.

When the light is condensed via an optical system such as a liquid crystal projector and the illuminance is largely illuminated on an irradiation surface at a separated position, for example, a screen, the light emitted from the discharge lamp passes through the optical system without any loss. It is important to reach the irradiation surface.

In order to reduce the loss and improve the illuminance on the irradiation surface, the arc of the discharge lamp needs to be narrowed down. The fact that the arc is narrowed means that the distribution of the arc temperature is sharp.

However, the emission of mercury is optically thick due to absorption, and the energy is absorbed by the absorption of the emission in the middle and low temperature areas, and the temperature rises. Arc cannot be squeezed.

On the other hand, it is known that when scandium or a rare earth metal is used as a luminescent metal and the luminescence is extremely increased, the arc can be narrowed even in the presence of mercury.

However, in the above case, if the lighting pressure of mercury is high, convection becomes intense and arc instability occurs, making it unpractical.

According to the present invention, the start-up characteristics can be improved, the illuminance of the irradiated surface can be increased, the dimming can be performed, and the restart voltage can be increased without essentially using mercury, which has a poor light rising characteristic at the start and has a large environmental load. It is an object of the present invention to provide a metal halide discharge lamp of a short arc type, which is low in airtightness and in which an airtight container is hard to burst, a metal halide discharge lamp device and a lighting device using the same.

[0021]

According to the first aspect of the present invention, there is provided a short arc metal halide discharge lamp, comprising: a fire-resistant, translucent airtight container; a pair of electrodes sealed in the airtight container; Containing a halide, a second halide and a rare gas in a hermetic container, and the first halide is one or more kinds selected from the group consisting of sodium Na, scandium Sc, and a rare earth metal. A discharge medium, wherein the second halide is one or more halides of metals of iron Fe, zinc Zn, and aluminum Al having a relatively high vapor pressure;
, And is essentially characterized by not containing mercury.

In the present invention and each of the following inventions, definitions and technical meanings of terms are as follows unless otherwise specified.

First, the airtight container will be described.

A fire-resistant and light-transmitting hermetic container is a material having fire resistance enough to withstand a normal operating temperature of a discharge lamp, and is required to emit visible light in a desired wavelength region generated by discharge to the outside. As long as it is possible, it may be made of any material. For example, quartz glass, translucent alumina, ceramics such as YAG, or a single crystal thereof can be used.

If necessary, a halogen-resistant or metal-resistant transparent film is formed on the inner surface of the airtight container.
Reforming the inner surface of the airtight container is allowed.

Next, the electrodes will be described.

The short arc type metal halide discharge lamp of the present invention may be configured to be operated by either AC or DC.

Therefore, the pair of electrodes have the same structure when operated by an alternating current, but when operated by a direct current, the anode generally has a larger heat dissipation area than the cathode because the temperature rises sharply.

In the short arc type, the light emission of the discharge lamp is brought as close as possible to a point light source by reducing the distance between the electrodes formed in the hermetic container so that the light can be efficiently collected by an optical system such as a reflecting mirror or a lens. Is going to go,
In the present invention, the distance between the electrodes is actually 6 mm or less. That is, if the distance between the electrodes exceeds 6 mm, the upward curvature of the arc due to the convection of the discharge medium becomes too large.

Therefore, in the present invention, the short arc type means one having a distance between the electrodes of 6 mm or less. But,
It is preferably 4 mm or less, and most preferably 1 to 3 mm for projection for a liquid crystal projector or the like. The distance between the electrodes is measured at the tip of the electrode.

Next, the discharge medium will be described.

In the present invention, the discharge medium comprises the first halide, the second halide and the rare gas as described above.

The first halide is a metal halide having good starting characteristics and emitting visible light. The vapor pressure during lighting of these metals is not always high. Any one or more of them can be used as long as they are within the group consisting of the luminescent metals specified above.

The second halide is the metal having a relatively high vapor pressure during lighting. High vapor pressure means
It is not necessary to be too large as in mercury, and is preferably about 5 atm or less.

The second halide is not one that does not inhibit the emission of visible light, but is acceptable as long as the ratio to the total visible light emitted by the discharge lamp is small and the influence is small.

As the halogen constituting the first and second halides, iodine is most suitable for reactivity.
The reactivity increases in the order of bromine, chlorine, and fluorine,
Any of the above may be used if necessary. Also, different halogen compounds such as iodide and bromide can be used in combination.

The rare gas acts as a starting gas and a buffer gas. The rare gas is not particularly limited as long as it does not pass through the airtight container. However, since neon easily permeates quartz glass, the case where the airtight container is formed of quartz glass is used. Is recommended for argon, krypton or xenon.

Further, mercury will be described.

In the present invention, the fact that mercury is not essentially enclosed is defined as 0.1 mg / cc of the inner volume of the airtight container.
Means less than, preferably less than 0.2 mg, of mercury is present.

However, it is environmentally desirable not to encapsulate any mercury.

In the case where the electric characteristics of the discharge lamp are maintained by mercury vapor as in the prior art, the inner volume 1c of the hermetic container is required.
Based on the fact that 20 mg or more was filled per c, it can be said that the present invention has a substantially low mercury amount.

Finally, the operation will be described.

As is apparent from the above description, in the present invention, in addition to the first halide, which is a metal halide mainly responsible for emitting visible light, a metal halide having a relatively high vapor pressure is used. Is sealed in place of mercury as the second halide, the lamp voltage is determined mainly by the evaporation amount of the second halide. When the second halide is incompletely evaporated, the amount of evaporation is determined by the vapor pressure of the second halide. The vapor pressure is determined by the coldest part temperature.

The second halide has a lower vapor pressure during operation than mercury, but is clearly higher than the first halide and is not more than 5 atm.

In addition, with the combination of the first and second halides, the rising characteristics were better than when mercury was sealed.

Therefore, the lamp voltage of the discharge lamp is lower than that of the prior art in which mercury is sealed, but the difference is small. Considering that this type of metal halide discharge lamp is operated by an electronic lighting device, there is no problem in practical use. There is no range.

However, the lamp voltage can be further increased by applying a heat retaining means to the airtight container if desired.

Further, since the vapor pressure during lighting does not become extremely high, the burst of the airtight container during lighting is reduced.

Further, the discharge lamp of the present invention has the same luminous efficiency and slightly improved color rendering.

As described above, in the present invention, the characteristics at the steady state are almost the same as those of the prior art. However, it should be noted that the illuminated surface, for example, the screen illuminance is dramatically improved. That is, when combined with an optical system for a liquid crystal projector, the screen illuminance can be improved by about 40%. This is because the arc of the discharge lamp is narrowed and the arc temperature distribution shows a sharp gradient.

Since the arc of the discharge lamp of the present invention is narrowed as described above, it can be used not only for a liquid crystal projector but also for an automobile headlight, a store lighting device, a fiber optic lighting device, etc. used in combination with a reflector. Even when used in an optical system of a simple reflecting mirror, the illuminance on the irradiation surface can be improved.

The short arc type metal halide discharge lamp according to the second aspect of the present invention is the short arc type metal halide discharge lamp according to the first aspect, wherein the second halide is:
Cadmium Cd, magnesium Mg, cobalt Co, chromium Cr, nickel Ni, manganese Mn, antimony S
b, beryllium Be, rhenium Re and gallium Ga
Wherein one or more halides selected from the group consisting of are added.

The present invention specifies a metal suitable as the second halide.

According to a third aspect of the present invention, there is provided a short arc type metal halide discharge lamp according to the first or second aspect, wherein the second halide is contained in an amount of 0.1 to 1 / cc of the inner volume of the hermetic container. It is characterized by being enclosed in 5 mg.

The present invention specifies a suitable range of the amount of the second halide to be encapsulated. Depending on the halide to be encapsulated, the preferred range is even narrower, but it is acceptable to note that the overall range is noted.

A metal halide discharge lamp according to a fourth aspect of the present invention is the short arc type metal halide discharge lamp according to any one of the first to third aspects, wherein the rare gas is sealed at a pressure of 1 to 15 atm. It is characterized by.

According to the present invention, the pressure of the rare gas is increased to improve the luminous flux rising characteristics. Good luminous flux rising characteristics are extremely important in liquid crystal projectors, automobile headlights, and the like. But,
It is not so important for store lighting.

A short arc type metal halide discharge lamp according to a fifth aspect of the present invention is the short arc type metal halide discharge lamp according to any one of the first to fourth aspects, wherein the airtight container has an inner volume of 1 cc or less. A distance between the electrodes of the pair of electrodes is 6 mm or less;

The present invention defines a preferable specific numerical range for obtaining a metal halide discharge lamp which is small and has a short arc shape and is close to a point light source which can be replaced with a conventionally used small incandescent lamp. It was done.

The inner volume of the airtight container is preferably within a range of 0.1 to 1 cc for applications such as a liquid crystal projector and a store lighting fixture. For applications such as headlights for automobiles and optical fiber lighting devices, it is preferable to use a light emitting device such as a light emitting device.
005 to 0.1 cc is appropriate.

The distance between the electrodes is as described in claim 1.

A short arc type metal halide discharge lamp according to a sixth aspect of the present invention is the short arc type metal halide discharge lamp according to any one of the first to fifth aspects, wherein the heat is maintained around the airtight container on at least one electrode side. Means are provided.

The present invention is intended to maintain the electric characteristics by the vapor pressure of the second halide.
Since the vapor pressure of the halide is lower than that of mercury, the vapor pressure can be made as high as possible by using the heat retaining means in combination.

As the heat retaining means, a known configuration can be adopted. When combined with a reflecting mirror, it is preferable to form a heat retaining film on the outer surface of an airtight container surrounding the electrode on the light emitting opening side of the reflecting mirror. Good.

A metal halide discharge lamp device according to a seventh aspect of the present invention is characterized in that a rotating quadratic curved reflecting mirror is integrated with the reflecting mirror so that the light emission center is located at a position substantially at the focal point of the reflecting mirror. And a short arc type metal halide discharge lamp according to any one of the preceding claims.

The present invention combines a short arc type metal halide discharge lamp with a reflector. By integrating both, optical performance can be easily exhibited, so that the present invention is suitable for a projection type image display device such as a liquid crystal projector and an overhead projector. The reflecting surface of the reflecting mirror is formed by a multilayer interference film, infrared rays are transmitted,
Only visible light can be reflected.

An illumination device according to an eighth aspect of the present invention includes: an illumination device main body; and a short arc type metal halide discharge lamp according to any one of claims 1 to 6 supported by the illumination device main body. It is characterized by:

The present invention is applicable to all devices using the short arc type metal halide discharge lamp according to claims 1 to 6 for some illumination purpose, and in particular, to optical devices such as reflectors and / or lenses. It is suitable for a lighting device used in combination with the system, for example, a liquid crystal projector, an overhead projector, an automobile headlight, an optical fiber lighting device, a store lighting device, and the like.

[0069]

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

FIG. 1 is a front view showing a short arc type metal halide discharge lamp according to a first embodiment of the present invention.

In the figure, 1 is an airtight container, 2 is an electrode, 3
Is a sealing metal foil, and 4 is an external lead wire.

The airtight container 1 is made of quartz glass having an inner diameter of 14 mm.
And a pair of elongated sealing portions 1a, 1a are integrally provided at both ends of the ellipse in the major axis direction.

The electrode 2 is formed by winding the electrode coil 2b with the electrode shaft 2a and the tip of the electrode shaft 2a projecting slightly. The base of the electrode shaft 2a is welded to one end of the sealing metal foil 3 in the sealing portion 1a. The distance between the electrodes is 4mm
Is set to

The sealing metal foil 3 is made of molybdenum foil,
An external lead wire 4 is welded to the other end while being hermetically sealed in the sealing portion 1a.

In the hermetic container 1, a rare gas, a first halide and a second halide are sealed as a discharge medium.

As a rare gas, 500 torr of argon was sealed.

1.3 mg of sodium iodide was sealed as the first halide.

As the second halide, 8 mg of the halide shown in Table 1 was sealed.

With respect to the obtained short arc type metal halide discharge lamp, the lamp was lit at a constant input power of 150 W, and the lamp voltage, luminous efficiency and color temperature were measured together with the following conventional examples. Shown in

As a conventional example, 13 mg of mercury was sealed in place of the second halide.

[0081]

Table 1 Lamp No. 2 halogenide Lamp voltage (V) Luminous efficiency (lm / W) Color temperature (K) Screen illuminance ratio 1 (conventional example)-75 71 8700 1.0 2 AlI3 62 729 9120 1.4 3 FeI2 70 70 9210 1.35 4 ZnI2 73 68 9160 1.42 From Table 1, in this embodiment, a metal halide discharge lamp having a lamp voltage of 50 V or more, luminous efficiency and color temperature similar to those of the conventional example was obtained. .

Next, some of the above discharge lamps were combined with the optical system shown in FIG. 2 to measure the screen illuminance ratio. The results are shown in Table 1.

FIG. 2 is a conceptual illustration of the optical system of the RGB color separation type liquid crystal projector.

In the figure, 5 is the metal halide discharge lamp shown in FIG. 1, 6 is a reflecting mirror, 7 is an ultraviolet / infrared cut filter, 8a and 8b are color separation dichroic mirrors,
9B, 9G and 9R are liquid crystal panels, 10a and 10b are mirrors, 11a and 11b are color combining mirrors, 12 is a projection lens, B is a blue optical axis, G is a green optical axis, and R is a red optical axis.

The liquid crystal panel 9B is driven by blue, 9G is green, and 9R is driven by red image signals.

As is clear from Table 1, the discharge lamp of the present embodiment has a screen illuminance about 1.4 times that of the conventional example.

Next, the results of measuring the arc temperature distributions of the discharge lamp of the present embodiment and the conventional example will be described with reference to FIG.

FIG. 3 is a graph showing the arc temperature distribution of the lamp 2 of the present embodiment and the conventional example in Table 1.

In the figure, the horizontal axis indicates the radial position in the center cross section between the electrodes of the airtight container, and the vertical axis indicates the arc temperature (K).

A curve A is an arc temperature distribution curve of the lamp 2 of the present embodiment, and a curve B is a conventional arc temperature distribution curve. It can be seen that the arc is narrowed in the discharge lamp of this embodiment.

Further, with respect to the lamps 2 and 3 of this embodiment in Table 1 and the conventional example, the input power 70 W, 90
Table 2 shows the measurement results of the color temperature when the lamp was turned on at W, 110 W, and 130 W.

[0092]

Table 2 Lamp 70W 90W 110W 130W 1 (conventional example) 6510K 6930K 7560K 8030K 2 8630K 8740K 8900K 9060K 3 8720K 8860K 9030K 9180K As described above, in the conventional example, when the input is reduced, light emission from mercury is relatively caused. Is dominant, so that the color temperature is significantly reduced.

However, in this embodiment, mercury is not essentially enclosed, and the amount of visible light emitted by the second halide is small. Therefore, even when the input is reduced, the light emitted by the luminescent metal is mainly emitted. Light emission. And
The color separation temperature at which the vapor pressure of the luminescent metal decreases as the input decreases decreases slightly.

In the above case, from 150 W (see Table 1) to 7 W
When it is changed to 0 W (see Table 2), 21
It changed by 90K.

On the other hand, in the present embodiment, 50
It stayed below 0K.

Next, the results of the evaluation of the restart are shown in Table 3.
Shown in

[0097]

[Table 3] Lamp restart voltage (KV) 1 (conventional example) 12 2 4 3 3 4 5 As shown in Table 3, in this embodiment, the restart voltage is low. This is because the vapor pressure during operation of the second halide is lower than that of mercury.
This is because the pressure is 6 atm and other halides are at most 5 atm. Therefore, the starting characteristics are improved.

On the other hand, in the conventional example in which mercury is sealed, the pressure is 28 atm, so that the restart voltage is high as shown in Table 3.

FIG. 4 is a front view in central section showing a second embodiment of the short arc type metal halide discharge lamp of the present invention.

In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, the inner volume of the airtight container 1 is set to 0.
The difference is that it is a small metal halide discharge lamp of 05 cc.

The airtight container 1 has an inner diameter of 4 mm.

The electrode 2 has no electrode coil.
The distance between the electrodes is 4.2 mm.

The discharge medium is as follows. 1 atm xenon, the first halide is scandium iodide Sc
0.14 mg of I3 and 0.8 of sodium iodide NaI
6 mg was enclosed. Further, as the second halide,
1 mg of the halide shown in Table 4 was enclosed.

The short arc type metal halide discharge lamp thus obtained was lit at a constant input power of 35 W, and the lamp voltage, luminous efficiency, color rendering, and color temperature were changed.
Table 1 also shows the results measured together with the following conventional examples.

In the conventional example, 1 mg of mercury was sealed in place of the second halide.

[0107]

Table 4 Lamp Second Halo Halide Compound Lamp Voltage (V) Luminous Efficiency (lm / W) Color Rendering (Ra) Color Temperature (K) 1 (Conventional Example)-8380 63 4120K 2 AlI3 62 78 65 3860K3 FeI2 70 73 71 4210K 4 ZnI 2 75 78 65 3830K As is apparent from Table 4, in the present embodiment, the lamp voltage is 50 V or more, and the luminous efficiency is slightly lower than the conventional example, but the color rendering properties tend to be improved. Was.

From the above, it can be evaluated that the characteristics of the present embodiment in the steady state are almost equal to those of the conventional example.

Next, the lamp 3 of the present embodiment shown in Table 4
And lamp 1 (conventional example), input power 15 W, 2
Color rendering properties when lit at 0W, 25W and 30W (R
Table 5 shows the measurement results of a) and the color temperature (K).

[0110]

Table 5 Lamp 15W 20W 25W 30W 1 (conventional example) Color rendering (Ra) 40 45 58 61 Color temperature (K) 5640 4970 4630 4350 2 Color rendering (Ra) 63 64 65 66 Color temperature (K) 4430 4340 4210 4140 As shown in Table 5, when the input is changed from 35 W (see Table 4) to 15 W in the conventional example, the color temperature becomes 1430K.
The color rendering was changed by 23. In this case, the change is so large that dimming cannot be performed in practice.

On the other hand, in the present embodiment, the change in color temperature is 190 K, and the change in color rendering is only 6, so that sufficient dimming is possible.

When the outer tube is housed in the outer tube and the outer tube is evacuated, the efficiency of the present embodiment greatly increases. This is because mercury self-absorbs in a low temperature portion, that is, around the arc, obtains energy, and the temperature of that portion rises, and the temperature difference from the central portion of the arc relatively disappears, so that the arc becomes thicker. In contrast, in the case of the present embodiment, since there is no mercury, the temperature difference between the periphery and the center of the arc is large and the heat loss is large. However, the presence of the outer tube reduces the heat loss, and in this embodiment without mercury, the action of the outer tube increases.

FIG. 5 shows a second embodiment of a short arc type metal halide discharge lamp according to the present invention.
11 is a graph showing the relationship between the light-filling time and the sealing pressure of e.

In the figure, the horizontal axis represents the Xe filling pressure (atmospheric pressure).
, And the vertical axis indicates the luminous flux rise time (second).

As is clear from the figure, when the filling pressure is 1 atm or more, the rising time of the luminous flux is remarkably reduced.
At less than one atmosphere, it is significantly longer.

FIG. 6 shows a second embodiment of the present invention.
5 is a graph showing the relationship between the amount of lamp and the lamp voltage when iron iodide FeI2 is used as the second halide.

In the figure, the horizontal axis represents the amount of FeI 2 encapsulated (m
g / cc), and the vertical axis indicates the lamp voltage (V).

It is understood from the figure that the lamp voltage exceeding 30 V is 1 mg or more per 1 cc of the inner volume of the airtight container.

It is noted that 20 cc per 1 cc of the inner volume of the hermetic container
If the amount is more than 0 mg, the luminous efficiency is reduced because unevaporated FeI2 absorbs light.

FIG. 7 is a partially sectional front view showing an embodiment of the metal halide discharge lamp device of the present invention.

In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, the short arc type metal halide discharge lamp 5 and the reflecting mirror 6 shown in FIG. 1 are integrated.

Reference numeral 5b denotes a heat insulating film which is formed on the outer surface of the airtight container 1 surrounding the electrode on the light-projecting opening side of the reflecting mirror 6 of the metal halide discharge lamp 5.

The reflecting mirror 6 is formed by glass molding. The reflecting mirror 6 has a neck portion 6a on the top and a reflecting mirror main portion 6b.
Visible / infrared transparent multilayer interference reflection film 6 on the inner surface
c has been deposited. Further, a through hole 6d is formed in the reflecting mirror main body 6b.

Then, the metal halide discharge lamp 5 is
The base 5a is fixed in the neck 6a via a base cement 7. Further, the power supply line 8 passes through the through hole 6d of the reflecting mirror 6 and is led out to the rear side of the reflecting mirror 6.

Reference numeral 9 denotes an electronic lighting device which supplies a required voltage and lamp current to the metal halide discharge lamp 5.

FIG. 8 is a conceptual diagram showing a liquid crystal projector as a first embodiment of the illumination device of the present invention.

In the figure, the same parts as those in FIG. 7 are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 11 denotes liquid crystal display means, 12 denotes image control means, 13 denotes an optical system, 14 denotes a main body case, and 15 denotes a screen.

The liquid crystal display means 11 displays an image to be projected by a liquid crystal. The liquid crystal display means 11 emits the illumination light emitted from the metal halide discharge lamp 5 of the metal halide discharge lamp device from the back surface thereof and condensed by the reflecting mirror 6. You.

The image control means 12 drives and controls the liquid crystal display means 11, and can have a television receiving function if necessary.

The main body case 14 accommodates the above-described components.

The optical system 13 projects the light that has passed through the liquid crystal display means 11 onto a screen 15.

FIG. 9 is a front view of a short arc type metal halide discharge lamp according to a third embodiment of the present invention.

In this embodiment, a small short arc type metal halide discharge lamp similar to that shown in FIG. 4 is further mounted on an automobile headlight.

21 is an outer tube, 22 is a base, and 23 is an insulating tube.

The outer tube 21 houses therein a metal halide discharge lamp 5 ′ having a structure substantially similar to that shown in FIG. 4, and is sealed at both ends, and one end of the outer tube 21 is erected on a base 22.
The external lead wire 4 led out from the other end extends parallel to the outer tube 21 and is introduced into the base 22 and is connected to a terminal (not shown).

The insulating tube 23 covers the external lead wire.

FIG. 10 is a perspective view showing an automotive headlight as a second embodiment of the lighting device of the present invention.

In the figure, 31 is a reflecting mirror, and 32 is a front cover.

The reflecting mirror 31 is formed on a paraboloid of revolution having an irregular shape by molding plastics, and is configured so that a metal halide discharge lamp (not shown) shown in FIG.

The front cover 32 has a prism or a lens integrally formed by molding transparent plastics, and is hermetically mounted on the front opening of the reflecting mirror.

[0143]

According to the first to sixth aspects of the present invention, instead of mercury, a metal halide having a relatively high vapor pressure and low visible light emission is enclosed together with a light-emitting metal halide. As a result, it is possible to improve the starting characteristics without using mercury, which has a large environmental load. Can be provided.

According to the second aspect of the present invention, it is possible to provide a short arc type metal halide discharge lamp in which the second metal having a high vapor pressure and low visible light emission is specified.

According to the third aspect of the present invention, it is possible to provide a short arc type metal halide discharge lamp in which the amount of the second halide to be filled is defined.

According to the fourth aspect of the present invention, a short arc metal halide discharge lamp having a good luminous flux rising characteristic can be provided by additionally setting the rare gas sealing pressure to 1 atm or more.

According to the fifth aspect of the present invention, in addition, since the inner volume of the hermetic container is 1 cc or less and the distance between the electrodes is 6 mm or less, it can be replaced with a small incandescent lamp conventionally used. A short arc type metal halide discharge lamp close to a point light source can be provided.

According to the invention of claim 6, in addition to the provision of the heat retaining means around at least one of the electrodes, the short arc can easily maintain the vapor pressure of the second halide in a preferable high range. Shaped metal halide discharge lamps can be provided.

According to the seventh aspect of the present invention, it is easy to exhibit optical performance by being integrated with the reflecting mirror having a rotating quadric surface.
Moreover, a metal halide discharge lamp device having the effects of claims 1 to 6 can be provided.

According to the illumination device of the eighth aspect, it is possible to provide an illumination device having the effects of the first to sixth aspects.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of a short arc type metal halide discharge lamp of the present invention.

FIG. 2 is a conceptual explanatory diagram of an optical system of an RGB color separation type liquid crystal projector.

FIG. 3 is a graph showing an arc temperature distribution of the lamp 2 of the present embodiment and a conventional example in Table 1.

FIG. 4 is a front elevational view in central section showing a second embodiment of a short arc type metal halide discharge lamp according to the present invention.

FIG. 5 is a graph showing a relationship between a sealed pressure of xenon and a luminous flux rising time in a second embodiment of the short arc type metal halide discharge lamp of the present invention.

FIG. 6 is a graph showing a relationship between a charged amount and a lamp voltage in a case where FeI2 is used as a second halide in the second embodiment.

FIG. 7 is a partial cross-sectional front view showing one embodiment of the metal halide discharge lamp device of the present invention.

FIG. 8 is a conceptual diagram showing a liquid crystal projector as a first embodiment of the illumination device of the present invention.

FIG. 9 is a front view showing a third embodiment of a short arc type metal halide discharge lamp according to the present invention.

FIG. 10 is a perspective view showing an automobile headlight as a second embodiment of the lighting device of the present invention.

FIG. 11 is a graph showing an emission spectrum distribution of a conventional short arc type metal halide discharge lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hermetic container 1a ... Sealing part 2 ... Electrode 2a ... Electrode shaft 2b ... Electrode coil 3 ... Sealing metal foil 4 ... External lead wire

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Toshio Hiruta 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo Inside Toshiba Litec Corporation

Claims (8)

[Claims] An airtight container that is fire-resistant and translucent; a pair of electrodes sealed in the airtight container; and is enclosed in the airtight container containing a first halide, a second halide, and a rare gas. , The first halide is one or more halides selected from the group consisting of sodium Na, scandium Sc, and rare earth metals;
A discharge medium which is one or more halides of iron Fe, zinc Zn, and aluminum Al having a relatively high vapor pressure, and is essentially free of mercury. Short metal arc discharge lamp. 2. The second halide is cadmium Cd,
Magnesium Mg, cobalt Co, chromium Cr, nickel Ni, manganese Mn, antimony Sb, beryllium B
2. The short arc metal halide discharge lamp according to claim 1, wherein one or more halides selected from the group consisting of e, rhenium Re and gallium Ga are added. 3. A short arc type metal halide discharge lamp according to claim 1, wherein the second halide is sealed in an amount of 0.1 to 5 mg per 1 cc of the inner volume of the airtight container. 4. A short arc type metal halide discharge lamp according to claim 1, wherein the rare gas is sealed at a pressure of 1 to 15 atm. 5. The airtight container according to claim 1, wherein the inner volume of the airtight container is 1 cc or less; and the distance between the pair of electrodes is 6 mm or less. Arc-shaped metal halide discharge lamp. 6. A heat retaining means is provided around an airtight container on at least one electrode side.
6. A short arc type metal halide discharge lamp according to any one of claims 1 to 5. 7. A short arc type metal halide according to claim 1, wherein said reflector is a quadratic curved surface and said light-emitting center is located at a substantially focal point of said reflector. A metal halide discharge lamp device comprising: a discharge lamp; 8. A lighting device comprising: a lighting device main body; and a short arc type metal halide discharge lamp according to claim 1 supported by the lighting device main body.