JPS59151743A - Compact metal halide lamp - Google Patents

Abstract

PURPOSE:To prevent the unevenness of luminous colors and improve flickering out and then prevent the deterioration of luminous flux maintenance ratio by connecting a circuit so that an upper electrode can form a positive electrode and a lower electrode can form a negative electrode. CONSTITUTION:In a compact metal halide lamp below class 100 watts that lights at a perpendicular location where the axis of a luminous tube 2 is vertical using a DC regulator 5, a circuit is connected so that an electrode 9 located upward can form a positive electrode and an electrode 8 located downward can form a negative electrode. Consequently, since the mercury with large atomic weight is easy to collect downward and the metal halide with small atomic weight is easy to collect upward and the electrode 8 located downward is connected to the negative electrode (minus) of the DC regulator 5, the ions of the metal halide are drawn downward. Thus, the metal halide is prevented from being collected upward and the concentration distribution of the mercury and metal halide in the luminous tube 2 is uniformalized. As a result, the ununiformity and acattering of optical colors are removed in the vertical direction of the luminous tube 2 and uniform optical color distribution can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a small metal halide lamp of 100 watt class or less.

[Technical background of the invention and its problems]

In recent years, from the viewpoint of power saving, technological developments have been made to use metal halide lamps with excellent luminous efficiency in place of conventional incandescent light bulbs; for example, Japanese Patent Application Laid-Open No. 54-63567 is known.

In order to use metal halide lamps in place of incandescent light bulbs, it is necessary to downsize the metal halide lamps.
A small metal noride lamp of 00 watts or less is required.

When lighting this type of small metal halide lamp with an AC power source, if a choke coil ballast is used, the problem is that the choke coil ballast becomes relatively large and heavy, even though the lamp is small and lightweight. Shi, recently small size,
Attempts have been made to use lightweight DC ballasts.

However, when a small metal halide lamp is operated vertically using a DC ballast, and the upper electrode is connected to the negative electrode and the lower electrode is connected to the positive electrode, the following problems occur.

In other words, while the rung is lit, convection occurs between the mercury and metal halide vapor sealed in the arc tube, and the metal halide vapor, which has a smaller atomic weight than mercury, tends to collect above the arc tube6. . In addition, if the upper electrode is a negative electrode, ions of metal halide, especially ions of alkali metals, such as sodium, are attracted to the negative electrode, increasing the concentration of metal halide in the upper part of the arc tube. . As a result, metal halide vapor gathers in the upper part of the arc tube, and mercury vapor gathers in the lower part, causing unevenness in the luminous color in the upper and lower parts, resulting in non-uniform luminescent color. If the concentration of metal halide vapor above the arc tube becomes too high, the silica glass reacts with the metal halide and an alkali metal such as sodium to form silicon iodide, for example. This silicon iodide adheres to the vicinity of the electrodes and evaporates immediately after the lamp is started. However, since the vapor pressure of silicon iodide is extremely high, a high restriking voltage is generated during warming up, causing the lamp to turn off. Further, when the metal halide reacts with quartz as described above, the absolute amount of metal halide in the arc tube becomes insufficient, leading to a decrease in luminous flux maintenance rate and worsening the life span.

[Purpose of the invention]

The present invention was made based on the above circumstances, and its purpose is to provide a small metal halide lung that prevents unevenness of emitted light color, improves fading, and prevents a decrease in luminous flux maintenance rate. It is something to do.

[Summary of the invention]

That is, the present invention provides a circuit connection in which the upper electrode is the positive electrode and the lower electrode is the negative electrode in a small metal halide lamp of less than 100 watts, which is lit using a DC ballast with the arc tube in a vertical position. Features.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

Figure 1 shows a 40 Watt metal halide lamp, with 1
2 is an outer tube, 2 is an arc tube, 3 is a case made of synthetic resin, etc., to which the outer tube 1 is attached, 4 is a cap, 5 is a DC ballast housed in the case 3, and 6 is an AC power source. show.

As shown in FIG. 2, the arc tube 2 has electrodes 8 and 9 disposed facing each other within a substantially spherical pulp z made of quartz glass. These electrodes 8 and 9 are conventionally known electrodes in which a tungsten electrode coil is wound around a tungsten electrode shaft. Sealing portions 10 and 11 of arc tube 2
are sealed with metal foil conductors 12 and 13 made of molybdenum, etc., and the electrodes 8 and 9 are each sealed with metal foil conductors 12 and 13.
2.13 is connected. and metal foil conductor 12.1
3 are connected to the wells 14 and 15, and these metal 4 and 15 are connected to the DC ballast 5 in the case 3.
It is connected to the.

In this case, when the lamp is used in a vertical position with the base 4 facing upward as shown in FIG. , the electrode 8 located below is connected to the negative electrode (→) of the DC ballast 5. The DC ballast 5 is connected to the AC power source 6 via the base 4.
Inside is a predetermined amount of mercury and a metal halide, such as scandium-sodium iodide (ScI3-"Na
I) and a starting rare gas such as argon gas at a predetermined pressure.

As shown in Fig. 1, a small metal halide lamp with such a configuration is lit vertically with the cap 4 facing upward, or more precisely, when lit with the tube axis of the arc tube 2 in the vertical direction, the inside of the arc tube 2 is lit. In this process, mercury vapor and metal halide vapor generate convection, but at this time, mercury with a large atomic weight tends to gather at the bottom and metal halide with a small atomic weight tends to gather at the top. However, since the electrode 8 located below is connected to the negative electrode (→) of the DC ballast 5, it attracts the metal-logonide ions downward.Therefore, it prevents the metal halide from gathering upward. This makes the concentration distribution of mercury and metal halides in the arc tube 2 uniform.As a result, there is no unevenness or variation in light color in the vertical direction of the arc tube 2, resulting in a uniform light color distribution.

In addition, since the concentration distribution of metal halides becomes even within the arc tube 2, local reactions between metal halides and quartz are prevented, and the generation of silicon iodide and the like is reduced, so the re-ignition voltage Problems such as an increase in the brightness and fading out are prevented, and there is no absolute shortage of monometal halide, so there is no reduction in the luminous flux maintenance factor or deterioration of the lamp life characteristics.

In the above embodiment, since the small and lightweight DC ballast 5 is integrated with the lamp, there is no need for a special ballast outside the lamp, and it can be used as an alternative to incandescent bulbs in existing lighting equipment for incandescent bulbs. In particular, since a small and lightweight DC ballast is used, there is also the advantage that the entire lamp can be made smaller.

The results of experiments conducted on a 40 Watt small metal halide lamp will be explained below.

As shown in Fig. 2, the arc tube 2 has a rectangular spherical shape, the maximum distance t within the arc tube in the electrode axis direction is 9 mm, and the maximum inner diameter d in the direction orthogonal to the electrode axis direction is 8 mm. ing. Also, assuming that the protrusion height of the lower electrode 8 is hl and the protrusion height of the upper electrode 9 is h2, the reeds, these holes, and h
The table below shows the results of measuring the total luminous flux and color temperature while changing the dimensions and polarity of 2.

What can be determined from the above table is that the upper electrode 9 is
If the lower electrode 8 is set to (G), the emitted light colors will be separated and the luminous flux maintenance rate will drop significantly, but if the upper electrode 9 is set to (G) and the lower electrode is connected to (→), the emitted color will be even. Improvements in brightness and luminous flux maintenance rate were observed.Thus, the effects of the present invention are confirmed.

Further, the electrode height hl of the lower electrode 8 should be 1.0 mm or more, and the electrode height h2 of the upper electrode 9 should be 1.0 mm or more.

It is preferable to satisfy the relationship: <hz. Tsumashi, 1,
The effect is more effective in the range of 0 mm≦h1<h2≦3.5 mm. The reason for this is that if the electrode height is too low, the temperature of the quartz glass at the back of the electrode will rise significantly, promoting reactions between metals, rhodanides, and silica glass, making it easier to generate silicon iodide, etc. I'll go.

On the other hand, if the electrode height is too high, the temperature rise in the coldest part generated at the back of the electrode, especially the back of the lower electrode 8, will be low, and the evaporation of metal rhodanides will not be promoted, leading to a decrease in luminous efficiency. . In addition, the relationship ht<hz can be solved by increasing the height of the upper electrode to eliminate the temperature difference in the arc tube caused by convection, and in combination with the ion attraction effect of the lower electrode mentioned above, the metal rod This contributes to equalizing the concentration distribution of the oxide in the vertical direction and to preventing the reaction between the quartz on the back of the upper electrode 9 and the metal rhodanide.

In addition, a small metal halide lamp of 100 watt class or less must have a maximum distance t within the arc tube along the electrode axis direction of 12 mm or less, and when the dimension of t is 12 mm or less, 1,0 mm≦hl<h2≦. It has been confirmed that the effect will be further improved if the thickness is restricted to 3.5 mm.

In the embodiments shown in FIGS. 1 and 2, it has been explained that the lamp is used so that the entire lamp is in a vertical position and the lamp holder 4 is in an upward position. In the present invention, the lighting posture of the arc tube 2 is a problem, so as in the lamp shown in FIG. In short, the present invention is effective when the arc tube 2 is used in a vertical direction in a lamp configured as shown in FIG. In other words, even if the lamp having the structure shown in FIG. 3 is lit with the cap 4 in a horizontal position, the arc tube 2 is in a vertical position, so the present invention can be practiced even with such a lamp.

Note that the meaning that the arc tube 2 is used in a vertical position does not necessarily mean that the arc tube axis 0-0 is correctly oriented vertically, but that the arc tube axis 0-0 is within 30 degrees from the vertical line. This also applies to the case where the light is tilted at an angle of .

Furthermore, the DC ballast 5 is not limited to being integrated with the lamp, and may be separate from the lamp as shown in FIG.

The arc tube 2 is not limited to an elliptical shape, but may be spherical.

〔Effect of the invention〕

According to the present invention as described in detail above, the lower electrode connected to the negative electrode of the DC ballast prevents metal rhodanides from gathering upward in the arc tube due to their small atomic weight. It has the effect of attracting the ions of the above-mentioned metal rhodanides to equalize the concentration distribution of metal halides, preventing unevenness of luminescent color, improving luminous efficiency and luminous flux maintenance rate, and preventing fading. .

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, and FIG. 1 is a diagram illustrating how a small metal halide lamp is used;
FIG. 2 is a configuration diagram of an arc tube, and FIG. 3 is an explanatory diagram of another embodiment of the present invention in a state of use. 1... Outer tube, 2... Luminescent tube, 4... Cap, 5...
・DC stabilizer, 6...AC power supply, 8...lower electrode,
9... Upper electrode. Applicant's agent □ Patent attorney Takehiko Suzue 1st Figure 2 Figure 3 0

Claims (1)

[Claims] In a small metal halide lamp of 100 watt class or less that uses a DC ballast and is lit in a vertical position with the tube axis of the arc tube in the vertical direction, the electrode located above is the positive electrode and the electrode located below is the negative electrode. A small metal halide lamp characterized by a circuit connected to.