JPH04192253A - Metal halide lamp - Google Patents

Abstract

PURPOSE:To prevent a luminous tube from leaking, or being damaged during the life of the tube by forming a luminous tube narrow tare at a boundary section between a thin tube section and thick tube section into a thicker one in wall thickness than the thick tube section. CONSTITUTION:Paired electrodes sealed in both the ends of a luminous tube 1 made quartz, rear earth metals, thallium, tin, indium and at least one kind of alkali metallic iodides are sealed in the inside of the tube together with rare gas and mercury, and heat retaining films 2 and 2 are applied onto outer walls at the end sections of the luminous tube. The luminous tube 1 thus formed is mechanically and electrically supported via a luminous tube support 5 within an outer sphere 4 having a connector at its one end. The luminous tube 1 is formed out of a narrow tare 30 made of quartz glass by means of pull-down processing, and the boundary section of the tube between a thin tube section 32 and a thick tube section 31 is made thicker in wall thickness than the thick tube section 31. As a result, the luminous tube can thereby be prevented from leaking, being deformed and damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to metal halide lamps, and more particularly to improvements in quartz tubes used as arc tubes.

[Prior Art] Metal halide lamps generally have high efficiency and high color rendering properties, so they are widely used and small lamps are used as light sources for general indoor lighting. Lamps containing Dy, Tl, and Cs as additives in the arc tube not only have an average color rendering index and a special color rendering index of 90 or higher, but also have a color temperature of 90 or higher when the color temperature is set in the range of 4,500 to 5,000 K. The primary colors are expressed vividly, making it ideal for indoor lighting.

However, in order to obtain the best characteristics with this type of lamp, it is necessary to raise the temperature of the coldest part at the end of the arc tube to maintain an appropriate heat retention state.

The arc tube of a metal halide lamp filled with Sc-Na as an additive uses a straight tube-shaped quartz tare, but in the lamp filled with Dy, etc., a straight tube-shaped quartz tare is provided with small-diameter portions at both ends. A narrow quartz tare bag is used, the end of which is coated with a heat-retaining film, and the inside of the outer tube is vacuumed.

By the way, a narrow quartz tare bag formed by connecting small diameter parts used in this type of lamp has a shape as shown in FIG.

Generally, it is manufactured by using a glass lathe or the like to heat the ends of two quartz tubes with different wall thicknesses to high temperatures with a hydrogen burner, and then joining the softened ends of the quartz tubes to blend them together.

However, when using a narrow type tare, the reaction between the quartz and the inclusions is very active inside the arc tube during lamp operation, especially in the narrow part, and the part where the large tube and narrow tube are connected is in the most severe condition. becomes. In addition, the surface of the connected part is not as smooth as the other surfaces, so the reaction surface area becomes extremely large, and as the reaction progresses, countless holes are formed on the quartz surface due to erosion, and bulges occur at the end of the lamp's life. leakage or tare rupture may occur.

[Problems to be Solved by the Invention] The present invention has been made in view of the above points, and provides an arc tube design that prevents damage to the quartz tare, which is the material of the arc tube, and prevents the arc tube from leaking or bursting. It is something to do.

[Means for Solving the Problems] The configuration of the present invention uses a narrow tare made of quartz glass manufactured by a drawing process, a pair of electrodes are sealed at both ends, and rare earth metals, rare gases and mercury are contained inside. thallium,
In a metal halide lamp in which an arc tube containing at least one of tin, indium, or alkali metal iodide is supported within an outer bulb, the flesh at the boundary between the thin tube part and the thick tube part of the arc tube narrow tare. [Function] By forming the thickness as described above, active rare earth metals, thallium, tin, indium, or alkali metal iodine can be formed as a filler in the arc tube. In metal halide lamps that contain a type of compound, using a narrow tare with a smooth surface reduces the reaction rate, making it possible to prevent leaks and bursts.

[Example code] Embodiments according to the present invention will be described based on the drawings.

Figure 1 is a side view of a metal halide lamp.
is an arc tube made of quartz, with a pair of electrodes sealed at both ends, and a rare gas, mercury, and iodides of dysprosium, thallium, and cesium sealed inside, and a heat insulating film 2, 2 on the outer wall of the arc tube end. It is coated.

Such an arc tube is mechanically and electrically supported via an arc tube support 5 within an outer sphere 4 having a base 3 at one end.

It is then used as a lamp with a tube input of 150W.

Next, specific examples will be described.

Here, the debit tare is as shown in Figures 2 and 3.
It is formed by processing a straight quartz tube at an appropriate location using a glass lathe or the like to form a draw-down section, and then heating and softening the section to stretch the quartz tube thinly.

(Example 1) 150W Dy using a spherical outer sphere as shown in Fig. 1
-Tl-Cs based metal halide lamp, as shown in FIG. The wall thicknesses of the thin tube portions 32 are both 1 and 3 m[o. Using such a tare, predetermined amounts of dysprosium iodide, thallium iodide, and cesium iodide are sealed together with mercury and argon in an arc tube with a pair of coil-shaped electrodes sealed at both ends.

Then, 100 lamps each of the lamp of the present invention and a conventional arc tube lamp made of a connecting tare were manufactured.

Next, when we conducted an overload lighting test with an input of 170W, we found that most of the conventional lamps had bulged near the joints by 3,000 hours, and 60 of them leaked.

On the other hand, in some of the products of the present invention, a slight bulge occurred in the squeezed portion of the tare, but no leakage occurred even after 6,000 hours had passed.

(Example 2) Figure 4 shows a 250W Dy-Tl-C using a straight tube shaped outer sphere.
This is an S-type metal halide lamp, and predetermined amounts of mercury, argon, dysprosium iodide, thallium iodide, and cesium iodide are sealed in a narrow quartz tare arc tube similar to the above.

We made 50 trial lamps each consisting of arc tubes using the connecting tare shown in Figure 5(a) and the withdrawn tare shown in Figures 5(b) and (c), and when they were lit with an input of 280W as described above, we found that 2,000 yen after the lamp developed devitrification in the early stage of lighting.
By 0:00, 26 lights had leaked, and not only 4 of them had an outer bulb crank due to outer spherical discharge, but the remaining 5,000 bulbs had leaked.
Everything leaked by 0 hours.

On the other hand, although devitrification was observed in the lamp of the present invention with a drawdown tare (Fig. 5 (b)), there was no deformation of the arc tube by 4,000 hours, and bulge occurred after 6,000 hours. However, it did not lead to a leak.

In addition, the lamp for the tare balance of the present invention (Fig. 5 (C)) remained the same as above even after being lit for 2,000 hours, but 4.
After 500 hours, there were 35 lights with noticeable swelling, 6.0
After 00 hours, 23 lights leaked.

This is because Dy-Tl-Cs metal halide lamps use a draw-down tare, which has almost no large reactive surface area on the arc tube surface, like a connecting tare, to prevent arc tube leaks and associated ruptures. It shows that it is possible.

In the case of Fig. 5(a), a slight depression is created near the joined part, which is often thinner than the other quartz parts, and the surface of the joined part is not as smooth as other parts. If it reacts with additives, it will be eroded and lead to leaks.

However, in the case of (b), the wall thickness of the boundary between the thin tube part and the thick tube part is the same as that of the central part of the thick tube part, or it is slightly thicker, so even if it is eroded, it will not lead to arc tube leakage.
Further, if the wall thickness is as thin as 0.9 mm as shown in (c), bulging will occur at the end of the life.

In this way, in a Dy-Tl-Cs metal halide lamp, a narrow-type tare that has been subjected to a drawdown process is used, and the wall thickness of the quartz tube at the boundary between the thin tube section and the wide tube section is made larger than the wall thickness of the thick tube section. By designing the arc tube, deformation, leakage, and bursting can be prevented.

Note that although the Dy-Tl-Cs lamp was explained in the above example, almost the same effect was observed in lamps filled with other additives, such as thallium, tin, indium, and at least one type of alkali metal iodide. Ta.

[Effects of the Invention] As is clear from the above description, the metal halide lamp according to the present invention uses a narrow-type tare made of quartz that has been subjected to a drawdown process as an arc tube. By forming the thickness to be equal to or greater than the thickness of the thick tube portion, it is possible to obtain a lamp having advantages such as a long life without the possibility of leakage or bursting of the arc tube during the lamp life.

[Brief explanation of the drawing]

Fig. 1 is a side view showing one embodiment of the metal halide lamp according to the present invention, Fig. 2 is a side view of the main part of the arc tube, Fig. 3 is an explanatory diagram of the arc tube, and Fig. 4 is another embodiment. FIG. 5 is a side view of the example lamp, FIG. 5 is a sectional view of the main part of the arc tube, and FIG. 6 is a side view of the main part of the conventional arc tube.

Claims (1)

[Claims] (1) A narrow tare bag made of quartz glass is manufactured by a drawdown process, a pair of electrodes are sealed at both ends, and inside is a rare gas, mercury, and rare earth metal, thallium, tin, indium, or alkali metal iodide. In a metal halide lamp comprising an arc tube sealed with at least one of: Metal halide lamp made by forming.