JP2001338611A - High-pressure discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate non-lighting of lamps due to cracks at a sealed part without making a tubule unnecessarily long. SOLUTION: A transparent ceramic tube having tubules with a diameter smaller than that of a main tube at its both ends as a light-emitting tube. A heat-insulating means such as a heat-insulating mold is provided at a part protruding outward from the light-emitting tube of an electricity lead-in body airtightly fixed with glass sealing member at the ends of the tubules. A lead wire is connected to the electricity lead-in body, and the light-emitting tube is fitted in an outer globe of glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure discharge lamp, and more particularly to a high-pressure discharge lamp using a translucent ceramic as a material for an arc tube.

[0002]

2. Description of the Related Art Conventionally, quartz glass has been used as a material for an arc tube of a high-pressure discharge lamp. Recently, a high-pressure discharge lamp using a translucent ceramic as a material for an arc tube has been commercialized. . Among the high-pressure discharge lamps, in particular, in the case of metal halide lamps, if the material of the arc tube is quartz glass, the quartz glass and the metal halide, which is a luminescent substance, gradually react during lighting, which causes a deterioration in life characteristics. However, when the arc tube is made of a translucent ceramic, it does not easily react with the metal halide, which is a luminescent substance, so it has better life characteristics than a quartz glass arc tube, and since the arc tube can be made compact, lamp efficiency and color rendering properties are improved. A good lamp could be made. For these reasons, in recent years,
Lamps using translucent ceramics for the arc tube material have been put to practical use. However, at present, only low wattage lamps have been commercialized, and high wattage lamps have not been commercialized. This is because the higher the wattage, the more difficult it becomes to seal the translucent ceramic tube, which is a material of the arc tube, to the electricity introducing body.

[0003]

Normally, a sealing material having a thermal expansion coefficient intermediate between the thermal expansion coefficient of ceramic, which is the material of the arc tube, and the thermal expansion coefficient of the electric conductor is used as the sealing material. When the wattage becomes high, the wire diameter of the electricity introducing body must necessarily be increased, and if the temperature of the sealing portion is the same, the expansion and contraction of the sealing portion at the time of lighting and extinguishing are larger than that of the low wattage . For this reason, it was found that cracks occurred in the sealing material of the sealing portion or the ceramic tube due to aging while repeating the lighting cycle of turning on and off, thereby causing a problem that the lamp was turned off.

Therefore, as a countermeasure, when a measure was taken to reduce the temperature of the sealing portion by lengthening the arc tube thin tube portion, it was found that non-lighting due to cracks was improved. It has been found that, due to the increase in the gap, the amount of the luminescent substance accumulated in the gap increases, and a new problem that the lamp efficiency decreases occurs.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate lamp non-lighting caused by cracks in the sealing portion without making the thin tube portion unnecessarily long, for example.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a high-pressure discharge lamp in which an arc tube having a sealing portion with an electric introduction body inserted at an end is incorporated in an outer bulb. A heat retaining means is provided at a portion protruding outward from the arc tube. By providing the heat retaining means in this manner, it is possible to eliminate lamp non-lighting due to cracks in the sealing portion.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-pressure discharge lamp in which an arc tube provided with a sealing portion having an end inserted with an electric guide is incorporated in an outer bulb. A heat retaining means is provided at a portion protruding outward from the arc tube.

In a preferred embodiment of the present invention, for example, a translucent ceramic 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 used.
In the sealing portion, the electricity introducing body is hermetically fixed with a glass 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 placed in the arc tube. The lead wire is connected to the portion of the electric introduction body that is sealed and protrudes outward from the arc tube of the electric introduction body,
A high-pressure discharge lamp is characterized in that the outer bulb is made of glass, and at least a part of the portion of the electricity guide that protrudes outward from the arc tube is provided with a heat retaining tube.

By making the structure of the high-pressure discharge lamp in this way, it is possible to eliminate lamp non-lighting due to cracks in the sealing portion without making the thin tube portion unnecessarily long.
It is possible to manufacture a high wattage lamp using a translucent ceramic that has not been practically used.

In the case where the heat retaining means is the above-described heat retaining cylinder, various materials can be used. In the case of the high pressure discharge lamp using the translucent ceramic tube, quartz is used. Alternatively, ceramic can be suitably used.

[0011]

EXAMPLES The present invention will be further described below with reference to examples.

FIG. 2 is a schematic cross-sectional view of a luminous tube not using the heat retaining member according to the present invention. In the figure,
An arc tube made of a translucent ceramic tube includes a main tube 11 at a central portion and thin tubes 12 attached to both ends thereof. Both ends of the main pipe 11 are provided with narrow diameter portions 13 which are narrowed down through tapered portions 15 having a curved surface with a curvature radius R of 2 mm or more. The small diameter portion 13 and the small tube 12 are hermetically joined via an alumina disk 14, and the small diameter portion 13 has a linear portion between the portion where the disk 14 is mounted and the tapered portion 15. ing. Inside the outer end of the thin tube 12 at the outer end of the arc tube, an electric conducting body 24 made of a first metal, an electric conducting body 27 made of a second metal, and a ceramic sleeve 30 connected to an electrode pole core 21 are sealed with a sealing glass 40. It is more airtightly fixed.

A first coil 20 and a second coil 22 are provided on the electrode pole core.
Is wrapped around. The purpose of the second coil is to dissipate heat at the electrode tip to the rear of the electrode, and also to position the ceramic sleeve 30.

In the arc tube having such a structure, the thin tube 12
We prototyped a 400W lamp with varying power consumption. The inside diameter of the main body 11 is 16 mm, the inside diameter of the small diameter portion 13 is 10 mm, the radius of curvature R of the tapered portion is 5 mm, and the inside diameter of the thin tube 12 at both ends is 2 m
The length of the thin tube was changed to 18 mm, 21 mm, 24 mm, and 27 mm at m. The diameter of the electrode core 21 is 0.9 mm, and the first coil and the second coil are wound around the electrode core. The first metal constituting the electricity introducing body 24 is made of molybdenum, has a diameter of 0.5 mm and a length of 3 mm, and is butt-welded to the electrode core at a position of 25.

A second metal made of niobium having a diameter of 0.7 mm is butt-welded at a position 26 on the side opposite to the electrode of the first metal. The ceramic sleeve 30 is made of alumina and has an inner diameter of 0.75 mm, an outer diameter of 1.9 mm, and a length of 6 mm. The second metal forming the electricity introducing body 27 is fixed by a sealing glass 40 at a position where the second metal is inserted into the thin tube by about 3 mm.

As the sealing glass, an Al ₂ O ₃ —SiO ₂ —Dy ₂ O ₃ system was used. The sealing glass fills the gap between the electricity introducing body and the alumina sleeve and the gap between the alumina sleeve and the thin tube up to about 6 mm from the end of the thin tube. Mercury, dysprosium iodide, thallium iodide, sodium iodide, cesium iodide, and argon as a starting gas are sealed in the arc tube sealed at both ends.

The arc tube thus constructed was assembled in a vacuum outer tube to complete a lamp, and a lighting test was performed. FIG. 3 is a schematic configuration diagram of a high-pressure discharge lamp incorporating the arc tube. In the figure, 8 is the arc tube, 7 and 10 are the lead wires (7
Is a nickel plate, 10 is a nickel wire), and 9 is an outer sphere made of glass. FIG. 4 shows the relationship between the tube length and lamp efficiency when the lamp is lit vertically. As can be seen from FIG. 4, the longer the capillary length, the lower the efficiency. In addition, a life test was performed with vertical lighting. The life test was performed up to 9000H, and the results are shown in Table 1.

[0018]

[Table 1]

As can be seen from Table 1, a lamp having a length of less than 21 mm causes a 100% leak and a length of less than 24 mm.
Of the three lamps, one out of three lamps was leaked at about 6000H and turned off. No leak occurred with a 27-mm long tube. The leak was at the sealing portion of the upper thin tube, and cracks had occurred in the sealing glass.

We considered these leaking mechanisms as follows. Factors that determine the temperature of the sealing portion during lighting are roughly classified into those based on heat conducted through the electricity introducing body and those based on heat conducted through the alumina tube.

The ceramic used for the arc tube main tube and the thin tube is strong against pressure welding but weak against pulling. Therefore, the ceramics are shrunk by the shrinkage of the electric introducing member and the ceramic tube due to a decrease in the temperature of the sealing portion when the lamp is turned off. Then, the sealing glass was pulled, and it is assumed that cracks occurred due to the repetition of the light-on / off cycle during the life.

Further, the electricity introducing body is usually a metal, and since the metal has better thermal conductivity than ceramics, the temperature of the electricity introducing body decreases faster than that of the ceramic when the light is turned off. For that reason,
It is presumed that the shrinking speed of the electricity introducing body is faster and the force for pulling the ceramic and the sealing glass is increased, so that cracks are likely to occur. The shorter the capillary length, the higher the rate of cracks.The shorter the capillary length, the higher the temperature of the sealing part. It is presumed that cracks are likely to occur due to the increase.

From the above presumption, it was conceived that the occurrence of cracks could be reduced by slowing down the temperature at which the electricity was turned off at the time of turning off the light, and the present invention was made by this.

FIG. 1 is a schematic cross-sectional view of a structure in which the electric guide protruding outside the arc tube is covered with a ceramic tube. There is a measure to slow down the temperature drop. The specifications of the arc tube are the same as those shown in Example 1, and the ceramic tube covering the electricity introducing body has a length of 40 mm, an inner diameter of 1 mm, and an outer diameter of 5 mm. The arc tube thus constructed was assembled in a vacuum outer tube in the same manner as in Example 1 to complete a lamp, and a life test was performed up to 9000H with vertical lighting. Table 2 shows the results.

[0025]

[Table 2]

As can be seen from Table 2, by covering the electrical lead-in protruding from the thin tube with a ceramic tube, a life test of 9000 was obtained.
No leak occurred even after H passed. When a similar test was performed using a quartz tube instead of the ceramic tube, no leak occurred as in the case of the ceramic tube. In addition, as shown in the figure, it is preferable that the heat retaining cylinder is closely contacted with the sealing portion so that the exposed portion of the electricity introducing body does not appear as much as possible between the sealing portion and the heat retaining portion.

As can be seen from the above example, by attaching the heat retaining tube to a part of the electric guide protruding outward from the arc tube, the sealing can be performed with high efficiency without making the thin tube portion unnecessarily long. It is possible to manufacture a high-pressure discharge lamp free from lamp non-lighting due to cracks in parts.

[0028]

According to the present invention, lamp non-lighting due to cracks in the sealing portion can be reduced, and when the arc tube has a thin tube portion, the thin tube portion can be made longer than necessary.
Lamp non-lighting due to cracks in the sealing portion can be eliminated.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a light-emitting tube in which an electric introduction body is covered with a ceramic tube.

FIG. 2 is a schematic cross-sectional view of a configuration of an arc tube using no heat retaining member.

FIG. 3 is a schematic configuration diagram of a high-pressure discharge lamp incorporating an arc tube.

FIG. 4 is a diagram showing a relationship between the length of a thin tube and lamp efficiency.

[Explanation of symbols]

 8: Arc tube 9: Outer sphere 7, 10: Lead wire 11: Main tube 12: Narrow tube 21: Electrode core 27, 24: Electrically conductive body 40: Sealing glass

Continuing on the front page (72) Inventor, Shinji Taniguchi No. 1, Nishino-sho, Ino Babacho, Kichijo-in, Minami-ku, Kyoto, Kyoto Japan (72) Inventor: Shigeyuki Mori, Kichijo-in, Nishi-no, Kyoto, Kyoto No. 1 Nobaba-cho F-term in Nihon Battery Co., Ltd. (reference) 5C043 AA14 CC03 CD01 CD05 DD17 EA09 EB15 EB16

Claims (3)

[Claims] 1. A high-pressure discharge lamp in which an arc tube provided with a sealing portion having an electric guide inserted at an end thereof is incorporated in an outer bulb, and protrudes outward from the arc tube of the electric guide. A high-pressure discharge lamp characterized in that a heat retaining means is provided in a portion where the heat is applied. 2. A light-transmitting ceramic tube having a main tube and a narrow tube smaller in diameter than the main tube at both ends of the main tube is used as an arc tube, and the electric introducing body is hermetically sealed with a glass sealing material at a sealing portion. An electrode is connected to the center of the light-emitting tube of the light-introducing body, and an ionizable filler containing a metal halide is sealed in the light-emitting tube, and protrudes outward from the light-emitting tube of the light-introducing body. A lead wire is connected to the portion of the electricity introducing body, the outer bulb is made of glass, and a heat insulating tube is attached to at least a part of a portion of the electricity introducing body that protrudes outward from the arc tube. The high-pressure discharge lamp according to claim 1. 3. The high-pressure discharge lamp according to claim 2, wherein said heat retaining tube is made of quartz or ceramic.