JPH03283342A - Metal halide lamp equipped with reflecting plate - Google Patents

Abstract

PURPOSE:To hold constant for the duration of the life of a light-emitting tube the arc position of the light-emitting tube being lighted while in its horizontal position by specifying the ratio of a metal halide other than mercury halide to mercury halide, both of which are sealed in the light-emitting tube, and also specifying the quantity of the metal halide per unit capacity inside the light-emitting tube. CONSTITUTION:Mercury halide (Hg X) and a metal halide (MX) other than the mercury halide are sealed in a light-emitting tube 1 and the mole ratio of the mercury halide to the metal halide is in the range 0.17<=HgX/Mx<=1.2 and also the quantity of the metal halide (MX) is set within the range 0.1<=MX<=2.0(mg/cc) per 1cc of the capacity inside the light-emitting tube 1. As a result, free halogen set in a specific range in advance can be obtained from the initial period of lighting of a metal halide lamp, and the quantity of the free halogen is not fluctuated much after the lamp is lighted. The center position of the arc 9 of the light-emitting tube 1 being lighted while in its horizontal position is thereby held constant for the duration of the life of the tube 1.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a metal halide lamp, and in particular to a relatively small metal halide lamp that is placed in front of a reflector and lights up almost horizontally to distribute light in an optically limited area. This invention relates to a metal halide lamp with a reflector used as a light source for video images, etc.

[Conventional technology]

Conventionally, small short-arc metal halide lamps, which are constructed by integrally or removably combining an arc tube and a reflector without using an outer tube, have characteristics such as good color rendering and high luminous efficiency. It is used in overhead rad projectors, overhead type projection televisions, movie projectors, etc., and is becoming popular.

These devices are becoming more compact, and the metal halide lamps used as their light sources are
The degree of horizontal lighting is increasing. Conventionally, metal halide lamps used in such devices, for example, those with a rated lamp power of 150 W for vertical lighting, have an arc length of 5.5 mm, a maximum diameter of 1 m, an inner diameter of 8 w.
a.A nearly elliptical arc tube with an internal volume of 0.5 cc is filled with mercury and argon as a starting auxiliary gas at about 150 torr to achieve a predetermined lamp voltage, as well as dysprosium iodide and neodymium iodide. The molar ratio of cesium iodide was selected to be 3:2:6, and a total amount of 0.8 μm was sealed.

[Problem to be solved by the invention]

By the way, when a so-called short-arc metal halide lamp configured in this manner is arranged horizontally and lit, the center of the arc of the arc tube at the beginning of lighting is formed floating 0.2 m above the center between the electrodes. However, after 100 hours of lighting, the center of the arc floats 1.1W above the center between the electrodes. After a further 1000 hours of lighting, it will be located 1.6m above. At this point, the amount of mercury iodide, which is almost zero at the beginning of lighting, has decreased to 0.0.
9+ag also occurs. This is because a large amount of free iodine is generated during lighting and combines with mercury during non-operation.

When the lamp is lit horizontally in this way, if the center of the arc of the arc tube moves during the life of the lamp, large changes in illuminance will appear on the screen when used with a reflector to illuminate the screen, making optical design extremely difficult. .

This invention was made to solve the above-mentioned problems when a conventional metal halide lamp is lit horizontally.It prevents the arc from moving during the lamp life and maintains it in a fixed position, and combines it with a reflector. It is an object of the present invention to provide a metal halide lamp with a reflector, which allows a screen with little change in illuminance to be obtained.

[Means and effects for solving the problem] In order to solve the above problems, the present invention provides a reflector that is positioned in front of a reflector having a reflective surface such as a paraboloid or an ellipsoid, and is illuminated almost horizontally. In the metal halide lamp, the arc tube is filled with at least mercury halide (l (g 0.17≦)IgX/M
X) is 0, 1 ≦ M per 1 cc of arc tube internal volume.
X≦2. 0 (-g/cc).

As mentioned above, the amount per unit volume of metal halides other than mercury halides to be sealed in the arc tube is set, and the molar ratio of mercury halides and metal halides other than mercury halides is set during lighting. By selecting the ratio of the amount of free halogen generated in the lamp to the metal halide other than mercury halide, it is possible to obtain a certain range of free halogen from the beginning of lighting, and the amount of free halogen does not change much even after lighting. Therefore, the center position of the arc of the arc tube during horizontal lighting is kept constant throughout its life, and blackening is suppressed. This makes it possible to reduce changes in illuminance on the screen due to the combination with the reflector.

〔Example〕

Next, an example will be described. FIG. 1 is a partially cutaway perspective view showing an embodiment of a metal halide lamp with a reflector according to the present invention. In the figure, 1 is an arc tube made of a quartz container, equipped with electrodes 2゜2' at both ends, and has a maximum outer diameter of φ11.
, 5 m, maximum inner diameter φ9. 〇-, arc length 5 cotton, internal volume 0.4 cc quartz container contains 10 III g of mercury,
In addition to 150 torr of argon gas, a total weight of 0.5 mg of dysprosium iodide, neodymium iodide, and cesium iodide in a molar ratio of 3:2:6 as metal halides, and further as mercury halide. It contains 0.2μ of mercury iodide. As a result, the amount of metal iodide other than mercury iodide enclosed in the arc tube 1 is 0 per 1 cc of internal volume.
．． 510.4-1.25 (w1g/cc), and the ratio (molar ratio) of mercury halide (mercury iodide) to metal halide other than mercury halide (metal iodide) is 0.
It is 34.

In this example, mercury iodide is encapsulated as the mercury halide, but in the present invention, iodine, that is, halogen, may be encapsulated alone, and even if halogen is encapsulated alone in this way, Once operated, it becomes mercury halide, so in the present invention, it is expressed as mercury halide in order to most easily define the amount of halogen enclosed and to simplify the form of encapsulation.

The electrodes 2, 2' are electrically connected to edged molybdenum N3, 3', which molybdenum foils 3, 3' are further connected to molybdenum wires 4, 4'.

The wires 4 and 4' are connected to the base 5 and the nickel lead wire 6, respectively. Although not shown in the figure, ^I z Os・SiO is present at both ends of the arc tube l.
It is covered with a heat insulating film consisting of □, and is configured to obtain a constant vapor pressure.

Then, a reflector plate 7 with a cold mirror is attached so as to surround the arc tube 1 configured in this way, and the nickel lead wire 6 is led out of the reflector plate 7 and connected to a terminal 8 fixed to the outer wall surface of the reflector plate. are doing.

The metal lamp with a reflector configured as described above was lit horizontally using an electronic ballast capable of rectangular wave lighting at a lamp power of 150 W, and the floating state of the arc 9 of the arc tube l from the initial stage to the end of its life was measured. As a result of observation, at the initial stage of lighting, it was located 1.5 mm above the center between the electrodes, and 10
After lighting for 0 hours, there was no change at 1.5-, 100
Even after 0 hours of lighting, it was confirmed that there was only a 1.6 m upward levitation, and that there was no significant change. This is because mercury iodide is pre-filled with metal iodides other than mercury iodide, so there is free iodine separated from this mercury iodide in the arc, which causes metal iodides other than mercury iodide to be encapsulated. This seems to be because the proportion of the luminescent metal reacting with the quartz arc tube decreases, and the proportion of increase in free iodine due to this reaction decreases, so that the total amount of free iodine does not change much.

In the present invention, the amount of metal halide per unit volume and the molar ratio of mercury halide to metal halide other than the mercury halide are set as described in the claims. Next, an explanation will be given of an experiment conducted in setting the amount of the material to be filled into the arc tube.

The total amount of metal iodides other than mercury iodide (MX), the ratio (molar ratio) of mercury iodide (HgX) to metal iodides other than mercury iodide (MX), and the internal volume of the arc tube were varied to produce various lamps. was created and the changes in arc levitation were observed. As a result, the value of l1gX/MX was reduced to 0.
If the value is less than 17, the metal of the metal iodide reacts with the quartz container during its life, and free iodine is gradually generated, resulting in a state in which the arc gradually rises from its initial position, causing the arc position to move optically. This turned out to be undesirable.

Furthermore, if the value of HgX/MX is increased to exceed 1.2, there will be too much free iodine from the beginning, which will cause the arc to become thinner and more floating, causing the arc to grow on the wall of the quartz arc tube from the initial stage of lighting. Approach to 1.7m.

As a result, although there are no subsequent changes, the quartz and the enclosed additives react and cause devitrification, and the quartz arc tube swells. In addition, since there is a large amount of free iodine from the beginning, it becomes difficult for electrons to come out from the tungsten electrode, making the arc spot even smaller, which causes the electrode tip temperature to become too high, causing significant tungsten sputtering, causing early blackening and deteriorating the screen luminous flux. It turned out that this was not desirable.

On the other hand, if the amount of metal iodide per 1 cc of arc tube internal volume is less than 0.1 mg/cc, the vapor pressure will be low and the desired luminescent characteristics will not be obtained, resulting in a phenomenon that the color characteristics of the screen will deteriorate. arise. Also 2, Owrg/
If it exceeds cc, the vapor pressure will be too high, so a reaction with the quartz arc tube will occur early, and a large amount of iodine will be generated as a result of the reaction. Therefore, it has been found that there is no point in specifying the amount of mercury iodide and the amount of free iodine, and that either case is unfavorable.

Similar experiments were conducted on lamps using metal bromide and mercury bromide as the encapsulated metal halides.
Similar results were obtained with lamps using iodide.

Therefore, mercury halide (Hg) sealed in the arc tube
X) and a metal halide other than the mercury halide (MX
) ratio and I't'0.17≦HgX/M
1.2, and 0.1≦MX≦2.0 (sg/cc
), it has been found that it is possible to suppress changes in the arc levitation of the arc tube with lighting time and to prevent blackening of the arc tube.

In the above example, in order to change the amount of free halogen, mercury iodide, which generates iodine in the arc, was added for adjustment, but as mercury halide for adjustment,
Not only the same type of metal iodide, but also a different type of metal iodide such as mercury bromide may be added to the metal iodide such as dysprosium iodide, and the same effect can be obtained.

〔Effect of the invention〕

As explained above based on the embodiments, according to the present invention, by defining the ratio (molar ratio) of the metal halide other than mercury halide and mercury halide to be sealed in the arc tube as described above, By selecting the ratio between the amount of free halogen generated during lighting and metal halides other than mercury halide, and setting the amount of metal halides per unit internal volume as described above, light emission during horizontal lighting can be reduced. To easily realize a metal halide lamp with a reflector, which can maintain the arc position of the tube constant throughout its life without causing blackening of the arc tube, thereby reducing changes in illuminance on the screen. I can do it.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a metal halide lamp with a reflector according to the present invention. In the figure, ■ is the arc tube, 2.2' is the electrode, 33' is the molybdenum foil, 4.4' is the wire, 5 is the base, 6 is the lead wire, 7 is the reflector, 8 is the terminal, and 9 is the arc. show.

Claims (1)

[Claims] 1. In a metal halide lamp that is placed in front of a reflector having a reflective surface such as a paraboloid or an ellipsoid and is lit almost horizontally, the arc tube contains at least mercury halide (HgX). and a metal halide (MX) other than the mercury halide, the molar ratio of the mercury halide to the metal halide is in the range of 0.17≦HgX/MX≦1.2, and A metal halide lamp with a reflector, characterized in that the metal halide (MX) other than mercury halide is in the range of 0.1≦MX≦2.0 (mg/cc) per cc of internal volume of the arc tube.