JPS58165239A - Metal halide lamp - Google Patents

Abstract

PURPOSE:To improve the luminous efficiency and lengthen the lifetime, by making a whole luminous bulb of infrared ray absorption quartz to heighten the temperature of the minimum-temperature part and suppress the rise in the temperature of the maximum-temperature part. CONSTITUTION:The inside diameter d2 of the upper part of a lamp, which is vertically lighted, is made larger than that d1 of the lower part so that the volume of the upper half is larger than that of the lower half as to the lighting. Since the bulb 1 of the lamp is made of infrared ray absorption quartz, the temperature of the minimum-temperature section behind the lower electrode 2b is heightened to promote the evaporation of solidified sealed-in metal to enhance the luminous efficiency. Although the temperature of the bulb wall except the minimum-temperature section would rise because the whole bulb 1 is made of infrared ray absorption quartz, the volume of the upper half of the bulb is made larger to increase the distance between the bulb wall and the arc and the surface area of the bulb wall to diminish the bulb wall load (W/cm<2>). For that reason, the rise in the temperature of the bulb wall is suppressed toward the top of the bulb 1 to prevent thermal deterioration to lengthen the lifetime.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to measures for improving luminous efficiency in metal halide lamps.

[Technical background of the invention and its problems]

Metal halide lamps, which are formed by filling a transparent waste light tube equipped with electrodes with mercury, a metal aluminide, and a starting rare gas, are widely used because they are highly efficient and highly color rendering lamps. However, as energy-saving measures have recently become a social requirement, it is desired that this type of metal halide lamp be made even more efficient and have a longer lifespan.

It is generally known that the luminous efficiency of a metal halide lamp depends on the temperature of the coldest part of the arc tube, provided that the luminous metals enclosed are the same and have the same amount.

That is, halodanides such as sodium, scandium, and dysprosium are condensed in the coldest part of the arc tube and evaporated as the temperature of the coldest part increases. Therefore, when the temperature of the coldest part is raised, the amount of evaporation of the metal/N4) ionide increases, and the concentration in the tube increases, so that the luminous intensity improves and the efficiency increases.

Conventionally, proposals have been made to increase the temperature of the coldest part of the arc tube and form it with a lath. Infrared absorbing quartz is 5
It is made of ordinary quartz expressed by 102, mixed with iron or iron, and absorbs infrared rays.
It has the property of increasing its own temperature.

However, if the entire arc tube pulp is made of infrared absorbing quartz, the temperature of the coldest part will certainly rise, but the tube wall temperature 11 of the gate part in the coldest part will also increase. Especially the maximum temperature! However, the temperature rises even more than when conventional ordinary quartz is used, and as a result, the quartz and the quartz react with each other and deteriorate, resulting in a shortened lifespan.

[Purpose of the invention]

The present invention has been made based on these circumstances, and its purpose is to construct the entire arc tube pulp with infrared absorbing quartz to reduce the coldest part i! The purpose of this invention is to provide a metal halide lamp that not only increases the temperature change and improves the luminous efficiency, but also suppresses the rise in temperature of the highest temperature portion and has a longer life.

[Summary of the invention]

The present invention increases the temperature of the coldest part by forming the arc tube pulp with infrared-absorbing quartz, and when the arc tube pulp is turned on, the discharge space located above has a larger volume than the discharge space located below. By keeping the bulb wall at the highest temperature part formed on the upper side away from the arc and increasing the surface area of the pulp wall to reduce the load on the tube wall, the temperature rise of the above maximum temperature "-" can be suppressed. , 11''. [Embodiment of the Invention]' An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows the arc tube of a metal halide lamp for vertical lighting, and the shell arc tube is normally housed in an outer tube (not shown) to form a double tube structure. 1 is arc tube pulp;
is constructed entirely of infrared absorbing quartz.

Infrared absorbing quartz is a stone that can be made, for example, by mixing quartz powder (SIO2) with a small amount of iron oxide (F.0) and then melting and crystallizing it. The pulp 1 is provided with main electrodes 1m and 2b facing each other, and these main electrodes 2
m, 2b are connected to metal foils 4m, 4b such as molybdenum sealed in the sealing parts s*, sb, and the metal foils 4t
a 4 b are connected to external conductors 5a*gb. i
4 Lube 1 is filled with predetermined amounts of mercury, metal halide, and starting rare gas.

However, in a lamp that is lit vertically as described above, the lower inner diameter d1 in the discharge space is formed to the same size as a conventional lamp with the same output, whereas the upper inner diameter d2 is formed larger. It is shaped like a cylindrical shape with a larger diameter at the top. For this reason, the volume of the upper half is larger than that of the lower half, which is located on the lower side during lighting.

According to such a configuration, during lighting, the lower electrode 2
If the bulb 1 is made of infrared absorbing quartz, the temperature of the coldest part formed at the back (lower part) of b will be increased by more than k. t, b Infrared absorbing quartz absorbs infrared rays and stores heat in the tube wall.As it is a stone, its own temperature is high, and this is the coldest part of the earth! This increases the degree of strength compared to conventional ordinary quartz. Therefore, the evaporation of the enclosed metal condensed in the coldest part is promoted, and the luminous efficiency is increased.

Generally, when a metal halide lamp is lit, it discharges about 60 - of the input electric power as infrared energy, although the proportion is lower than that of an incandescent lamp. A part of this infrared energy is absorbed by the infrared absorbing quartz and used to raise the temperature of the coldest part, contributing to improving the luminous efficiency.

It should be noted that as the upper discharge space becomes larger, convection within this space becomes more active, and from this, the luminous efficiency increases (K).

If the entire tube is made of infrared absorbing quartz, the temperature of the tube wall will rise even in areas other than the coldest part.

In this example, in order to increase the volume of the upper part, the pulp wall on the upper side moves away from the center of the pulp and the rim shear arc in the radial direction, which makes it difficult to receive radiant heat from the arc. As the area of the pulp wall increases in the upper part, the local tube wall load (w/ag) is lowered. Therefore, the closer you get to the upper side, the higher the stone function that suppresses the increase in tube wall temperature. Since the temperature portion is formed near the tip of the upper electrode 2a, the temperature rise in this highest temperature portion is suppressed.Therefore, the pulp 1
, , , thermal deterioration is prevented, resulting in a long service life.

The table below shows the distance between the electrodes: 42 m58eI55889, N
a11□ 25”?, HE 7011I9, Alcon 9 gas 5
The results of a comparative experiment using 400W class lamps under the same conditions of 0 Torr are shown.

Sandel C has the configuration shown in FIG. Although Sample B has improved luminous efficiency compared to Sample Empress, it can withstand only about 2/3 of the lifespan.Sample C has been confirmed to be superior to Sample Empress in luminous efficiency and comparable to Sample Empress in terms of lifespan. It was done.

FIG. 2 shows a horizontally lit lamp.

In the case of horizontal lighting, the arc is curved upwards.

Therefore, the coldest part occurs at the lower part of the center of the pulp, as shown by point P in FIG. The highest temperature area occurs at the upper center of the nokurubu, as shown by the 9 points in Figure 1. The reason why the highest temperature occurs at the upper center (point 9) is due to the curvature of the arc.

In this example, infrared Ii! The internal volume of the upper half of the pulp 1 made of absorbed quartz is larger than that of the lower half. Tsumashi is practically an up-and-coming man! The wall is curved upwards. In this way, in addition to separating the highest temperature portion Q from the arc, the local tube wall load is reduced, thereby suppressing the temperature rise at the nine points.

The following table shows the distance between electrodes: 65 IIIs 8efs 10
"F%NaI 50iy, Hg 60iy and Ah
The results of a comparative experiment on 700W memel halide lungs under the same conditions of f gas 50 Torr are shown.
Note that the inner diameter d' of the tail portion and the inner diameter d'2 of the center portion indicate the illustrated positions in the agz diagram.

1 rate W) Sample A B' decreases by about 2/3 in life compared to sample A A'. Confirm that sample I6c' has the highest efficiency in comparison to the structure shown in FIG. 2, and is comparable to Sundel AA' in terms of service life.

[Effects of the Invention] As detailed above, in the present invention, the arc tube pulp is made of infrared-absorbing quartz, so the infrared-absorbing function of this pulp increases the temperature of the tube wall near the coldest part. Since the temperature of the part increases, the luminous efficiency improves. By making the discharge space located on the upper side larger than the lower side during lighting, the tube wall at the highest temperature part generated on the upper side is substantially farther from the arc) and the local tube wall load is reduced. becomes low, suppressing the rise in tube wall temperature at the highest temperature section. For this reason, even though infrared absorbing quartz is used, a decrease in life is prevented.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention and shows a vertical lighting arc tube, and FIG. 2 is a block diagram showing another actual side of the invention and showing a horizontal lighting arc tube. 1... Arc tube bulb, jlm, 2b... electrode. Applicant's agent Patent attorney Takehiko Suzue 1″′ Fang 1 figure, 2 figures:

Claims (3)

[Claims] (1) In a metal halide lamp that has an arc tube in which mercury, a metal rhodanide, and a starting rare gas are sealed in pulp with electrodes, the bulb is not made of infrared-absorbing quartz, and the bulb is not made of infrared-absorbing quartz and is A metal halide lamp characterized in that the volume of the discharging space is larger than the volume of the discharging space located below. (2) In a metal ride lamp in which the tube shaft is used in a vertical position, the diameter of the upper pulp is made larger than the diameter of the lower pulp than the central part between the electrodes. A metal halide lamp as described in scope item (1). (3) Claim (1) characterized in that in a metal halide lamp in which the tube shaft is used in a horizontal position, the pulp wall in the upper half of the bulb shaft is curved upward.
Metal halide lamps listed in section.