JP2001345074A - High-pressure vapor discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent elevation of a lamp voltage and evaporation of an alumina tube during the life, and realize the safe and stable property of a lamp without the breakage of outer tube in a high-pressure vapor discharge lamp in which a light translucent ceramic tube is used for a light emission tube and in which the rated lamp electric power is 360 W to 400 W. SOLUTION: This is the high-pressure discharge lamp in which a light emission tube made by light translucent alumina is incorporated in a glass outer tube wherein the inner part pressure is maintained at 0.2 Pa or less, and which has a structure wherein a glass pipe is installed whose thickness is 1.4 mm to 1.8 mm in order to surround all the side faces of the light emission main tube between the outer tube and the light emission tube, in which the rated lamp electric power Wt of the high-pressure discharge lamp is 360 W<=Wt<=400 W, and in which the maximum outer diameter of the light emission tube is 17 mm to 20 mm and the inner diameter of the glass pipe is 25 mm or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure vapor discharge lamp using a translucent alumina tube as an arc tube.

[0002]

2. Description of the Related Art In recent years, a ceramic metal halide lamp using a translucent ceramic tube as an arc tube has been developed to have a power of 150 W.
The following low wattage lamps have been put to practical use. This type of lamp has a longer life, higher lamp efficiency, and a longer life than a conventional metal halide lamp consisting of a quartz arc tube.
It has various features such as good color rendering properties, and is widely used for lighting in stores, lobby, and show windows.

[0003] This type of lamp is designed to have a higher tube wall load than a conventional metal halide lamp because the ceramic tube used for the arc tube has a higher heat-resistant temperature than quartz. This achieves high efficiency and high color rendering.

By the way, a lamp using a ceramic tube as an arc tube has a higher probability that the arc tube will be scattered if the arc tube is damaged during operation as compared with a lamp using a quartz arc tube. . Scattering of the arc tube is a phenomenon in which, when the arc tube is broken, pieces of the material constituting the arc tube scatter toward the inner surface of the outer tube. The reason that the ceramic lamp is more likely to cause scattering of the arc tube is due to the difference in the material of the arc tube.

[0005] In the event of such damage, the outer tube can be prevented from being damaged by adopting a structure in which the glass tube is placed over the arc tube as shown in FIG. FIG. 3 is a diagram showing a structural example of a metal halide lamp made of ceramic. An arc tube 1 made of a ceramic tube is surrounded by a glass tube 2 and is incorporated in a glass outer tube 3 kept in a vacuum or a rare gas atmosphere such as nitrogen. The glass tube 2 prevents the outer tube 3 from being damaged due to the direct collision of the scattered ceramic pieces when the lamp is broken, or improves the lamp characteristics by increasing the temperature of the arc tube. Further, in order to reduce the amount of ultraviolet radiation of the lamp, an ultraviolet cut glass may be used for the glass tube 2 in some cases.

[0006]

However, if a glass tube is placed over a light-emitting tube in a medium / high wattage lamp that generates a large amount of heat during operation, the temperature of the light-emitting tube rises more than necessary. It has been found that problems such as an increase in lamp voltage during the life and evaporation of the ceramic tube may occur. The present invention has been made based on such circumstances, and an object of the present invention is to provide a light-emitting ceramic tube having a rated lamp power of 360 W or more and 400 W or more.
An object of the present invention is to provide a high-pressure steam discharge lamp of W or less that prevents the above-mentioned increase in lamp voltage during the life and evaporation of the alumina tube, and realizes a safe lamp with stable characteristics without damage to the outer tube.

[0007]

In order to achieve the above object, the present invention is characterized by having the following arrangement. That is, the high-pressure vapor discharge lamp of the present invention uses a light-transmissive alumina tube having a main tube as an arc tube and narrow tubes smaller in diameter than the main tube at both ends of the main tube. Is hermetically fixed with a sealing material, an electrode is connected to the center of the arc tube of the electricity introducing body, and an ionizable filler containing a metal halide is sealed therein. It is incorporated in a glass outer tube maintained at a pressure of 2 Pa or less, and has a thickness of 1.4 mm or more between the outer tube and the arc tube so as to surround at least the entire side surface of the arc tube main tube. A high-pressure vapor discharge lamp having a rated lamp power Wt of 360 W ≦ Wt ≦ 400 W provided with a glass tube of 0.8 mm or less, wherein the maximum outer diameter of the arc tube is 1
It is not less than 7 mm and not more than 20 mm, and the inner diameter of the glass cylinder is not less than 25 mm.

As the material of the glass tube, heat-resistant glass that can withstand use at a temperature of 500 ° C. or more such as quartz or so-called Pyrex glass (trade name) is suitable, and so-called hard glass is suitable for the outer tube. ing. Further, as the metal used as the metal halide, a combination of (dysprosium, thallium, sodium), a combination of (dysprosium, thallium),
(Dysprosium, neodymium), or a combination of these metals with holmium, thulium, cesium, or the like is suitable.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to specific examples. (Specific Example 1) FIG. 1 is a view showing a structure of a lamp of a first specific example. Reference numeral 1 denotes an arc tube made of translucent alumina, 2 denotes a glass cylinder made of quartz, 3 denotes an outer tube made of hard glass, 4 denotes an arc tube main tube, and 5 denotes an arc tube thin tube. The inside of the outer tube 3 is maintained at a high vacuum of 2 × 10 ⁻² Pa or less by the getter 6.

Table 1 below shows, as a first specific example, the results of a trial production in which the maximum outer diameter of the arc tube 1 was 17 mm and 20 mm and the inner diameter of the glass tube 2 was changed in a lamp having a rated lamp power of 360 W. It is. The total length of the arc tube 1 is 78 mm, and the length of the main tube 4 is 38 mm. The length of the glass cylinder 2 is 38 mm so that the main pipe 4 completely covers it.
And Quartz glass was used for the glass cylinder 2 and had a thickness of 1.4 mm to 1.8 mm. In the arc tube, dysprosium iodide, holmium iodide, thulium iodide, sodium iodide, thallium iodide, and cesium iodide total 24 mg, mercury 18 mg and argon 10
kPa is enclosed. Initial lamp voltage is 120 ±
2V.

[0011]

[Table 1]

The increase in the lamp voltage in the table is a value which is higher than the initial value after lighting for 4000 hours. The presence or absence of evaporation of the ceramic tube was determined by the presence or absence of a deposit on the quartz tube or outer tube after lighting for 4000 hours. The lighting conditions were 5.5 hours on and 0.5 hours off repeatedly.

From Table 1, it can be seen that the larger the inner diameter of the quartz tube, the smaller the rise in lamp voltage. From the viewpoint of the lamp life, the smaller the increase in the lamp voltage, the better, but it is preferable that the voltage be within 10 V in consideration of the lamp going out in practical use.
It has been found that evaporation of the ceramic tube occurs when the difference between the inner diameter of the quartz tube and the maximum outer diameter of the arc tube is within 3 mm. It is considered that the cause of the evaporation is that the arc tube main tube has risen above the maximum operating temperature of the ceramic tube. From the above results, it can be seen that when the inner diameter of the quartz tube is 25 mm or more, the lamp voltage rise is small and a lamp without evaporation of the ceramic tube can be obtained.

(Specific Example 2) Table 2 below shows, as a second specific example, in a lamp having a rated lamp power of 400 W, the maximum outer diameter of the arc tube 1 was 17 mm and 20 mm, and the glass tube 2 was used.
3 shows the results of trial production in which the inner diameter of the sample was changed. The total length of the arc tube 1 is 78 mm, and the length of the main tube 4 is 38 mm.
mm. The length of the glass cylinder 2 was set to 38 mm so that the main pipe 4 was completely covered. Quartz glass was used for the glass cylinder 2 and had a thickness of 1.4 mm to 1.8 mm. In the arc tube, dysprosium iodide, holmium iodide, thulium iodide, sodium iodide, thallium iodide, and cesium iodide total 20 mg and 16.5 m of mercury.
g and 10 kPa of argon are enclosed. The initial lamp voltage was 120 ± 2V. That is, only the amount of mercury and the driving power are different from the lamp of the specific example 1.

[0015]

[Table 2]

The increase in the lamp voltage in the table is a value which is higher than the initial value after lighting for 4000 hours. The presence or absence of evaporation of the ceramic tube was determined by the presence or absence of a deposit on the quartz tube or outer tube after lighting for 4000 hours. The lighting conditions were 5.5 hours on and 0.5 hours off repeatedly. Although the increase in the lamp voltage is larger than that in the case of the specific example 1, it can be seen that the tendency almost coincides with the test result at the rated lamp power of 360 W. That is, even when the rated lamp power is 400 W, when the inner diameter of the quartz tube is 25 mm or more, a lamp voltage rise is small, and a lamp without evaporation of the alumina tube can be obtained.

From the above test results, the rated lamp power is 36
Maximum outer diameter of the arc tube main tube is 17m at 0W or more and 400W or less
If the inner diameter of the glass tube attached to prevent lamp breakage is set to 25 mm or more,
It can be seen that a lamp with excellent life characteristics with a small increase in the lamp voltage can be obtained.

FIG. 2 is a view showing a lamp structure in which the arc tube is the same, but the structure of the outer tube and the internal structure for mounting the arc tube are different from those in the example of FIG. The internal pressure and the positional relationship between the glass tube and the arc tube are basically the same as those shown in FIG. In FIG. 2, 1 is an arc tube made of translucent alumina, 2 is a glass cylinder made of quartz, 3 is an outer tube made of hard glass, 4 is an arc tube main tube, and 5 is an arc tube thin tube. Getter inside the outer tube 3
6 maintains a high vacuum of 0.2 Pa or less. With the lamp having such a structure, the same result as described above can be obtained.

In this embodiment, the length of the quartz tube is set to be the same as the length of the side surface of the arc tube. However, this dimension reliably prevents the outer tube from being damaged when the arc tube is damaged, and minimizes the heat retention of the arc tube. That's what we decided for. If the length of the quartz tube is made longer than the length of the arc tube main tube side surface, the heat retention of the arc tube increases, and the lamp voltage further increases. However, this length is the length of the arc tube (the main tube and both ends). If the length is equal to or less than the total length of the thin tubes, no problem occurs as long as the value is set in the above-mentioned numerical range. If the length of the quartz tube is shorter than the length of the arc tube main tube side surface, the scattered ceramic pieces may directly hit the outer tube when the arc tube is damaged, and the outer tube may be damaged.

That is, in the present invention, the length of the cylinder is
It is preferable that the length is not less than the length of the arc tube main tube and not more than the length of the arc tube. When the thickness of the quartz cylinder was 1.4 mm or more and 1.8 mm or less, there was almost no difference in test results due to the difference in thickness.

In the above specific example, quartz glass was used as the glass cylinder. However, the present invention is not limited to this.
Any glass may be used as long as it is heat-resistant, has a protective strength to protect the outer tube when the arc tube is broken, and has a visible light transmittance that does not significantly deteriorate the lamp light flux.

[0022]

According to the present invention, a ceramic high-pressure steam discharge lamp of 360 W or more and 400 W or less, which can reliably prevent the outer tube from being damaged due to the damage to the arc tube and has a small lamp voltage rise and excellent life characteristics.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a lamp of a first specific example.

FIG. 2 is a diagram showing another lamp structure.

FIG. 3 is a diagram showing a structural example of a metal halide lamp made of ceramic.

[Explanation of symbols]

 1 arc tube 2 glass tube 3 outer tube 4 arc tube main tube 5 arc tube thin tube 6 getter

Continuation of the front page (72) Inventor Jiro Honda Inosinobabacho, Kisho-in, Minami-ku, Kyoto-shi, Kyoto 1-term F-term in Nippon Battery Co., Ltd. 5C039 HH03 HH05 HH09 5C043 AA06 AA07 AA14 CC03 CD05 DD02 DD03 EA01 EC01 EC02

Claims (1)

[Claims] 1. A light-transmitting alumina tube having a main tube and a thin tube having a smaller diameter than the main tube at both ends of the main tube is used as an arc tube. The electrode is connected to the center of the arc tube of the electricity introducing body, and the arc tube is filled with an ionizable filler containing a metal halide. A glass having a thickness of 1.4 mm or more and 1.8 mm or less, which is incorporated into a kept glass outer tube and has a thickness between the outer tube and the arc tube so as to surround at least all side surfaces of the arc tube main tube. Lamp power W with a tube made of steel
A high-pressure vapor discharge lamp in which t is 360 W ≦ Wt ≦ 400 W, wherein the arc tube has a maximum outer diameter of 17 mm or more and 20 m or more.
m or less, and the inner diameter of the glass tube is 25 mm or more.