JP2003142033A - Ceramic metal halide lamp and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic metal halide lamp without elongating a capillary tube more than necessary, while preventing the non-lighting of the lamp, and having high reliability, and to provide the manufacturing technology of high reliability. SOLUTION: An electricity leading-in member inserted into an arc tube and connected to an electrode is air-tightly fixed to an end of a metallic pipe, an outer face of the capillary tube of the arc tube is covered by the metallic pipe, and the tube and the metallic pipe are air-tightly fixed by a glass sealing material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a sealing portion between an electric introduction body and a ceramic tube in a ceramic metal halide lamp using a translucent ceramic as a material of 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 metal halide lamp, but in recent years, a ceramic metal halide lamp using a translucent ceramic as a material for the arc tube has been put into practical use. In the case of a metal halide lamp, if the material of the arc tube is quartz glass, the quartz glass and the metal halide, which is a light emitting substance, gradually react with each other during lighting, which causes the deterioration of life characteristics. However, when the material of the light emitting tube is translucent ceramic, it does not easily react with the metal halide that is the light emitting material, so the life characteristics are better than that of a quartz glass light emitting tube, and since the light emitting tube can be made compact, the lamp efficiency and color rendering properties are improved. May be able to make a good lamp. For these reasons, in recent years, lamps using a translucent ceramic as the material of the arc tube have been put into practical use.

[0003]

One of the major technical problems of ceramic metal halide lamps is what kind of structure should be adopted for the sealing structure between the electric introduction body and the ceramic tube. The mainstream of the sealing structure of ceramic metal halide lamps currently commercialized is a method in which a glass sealing material is allowed to flow between the electric introduction body and the ceramic tube to perform sealing. FIG. 2 shows an example of a mainstream sealing structure.
As shown in FIG. 2, as the material of the electric introduction body of the sealing portion, particularly the portion sealed with the ceramic tube by the glass sealing material,
The structure using niobium is the mainstream. This is because niobium is a high melting point metal and is close to the coefficient of thermal expansion of ceramics. However, since niobium reacts with the halogen enclosed in the arc tube and causes the deterioration of the life characteristics of the lamp, it is necessary to have a structure in which niobium and halogen do not come into contact with each other. As an example of such countermeasures, a cermet of molybdenum and alumina, which has halogen resistance and a thermal expansion coefficient close to that of ceramics, is made, the cermet part is covered with a glass sealing material, and niobium and molybdenum with a small wire diameter are butt welded. A lamp with a structure in which even the molybdenum portion is covered with a glass sealing material is currently commercialized.

As a problem of the cermet method as shown in FIG. 2 (a), as the cermet increases in the proportion of alumina, the coefficient of thermal expansion approaches that of alumina, so that the occurrence of cracks due to the difference in thermal expansion is reduced. However, there is a case where the conductivity is deteriorated and it is difficult to weld with a metal, so that an electric connection method with the outside is devised.

In the method of butt-welding niobium and molybdenum as shown in FIG. 2 (b), molybdenum does not have a coefficient of thermal expansion close to that of niobium, so that thermal expansion is required unless measures such as reducing the wire diameter are taken. Due to the difference in the coefficient, a crack may occur in the glass sealing material during lighting, and the lamp may not light. For this reason, at present, low wattage lamps of 400 W class or less (so-called lamps that do not need to have a large wire diameter)
However, the high wattage lamp, which requires a larger wire diameter of the electric introducer, has not been commercialized.

Next, a glass sealing material, Al ₂ O ₃ -SiO ₂ -D is used in the currently commercialized ceramic metal halide lamps.
Many y ₂ O ₃ based glass sealing materials are used. This Al ₂ O
_{The 3} -SiO ₂ -Dy ₂ O ₃ -based glass sealing material reacts with the metal halide when the temperature of the glass sealing material becomes high while the lamp is on,
It adversely affects the life characteristics. Therefore, the temperature of the glass sealing material during lighting should be as low as possible. Thin part of ceramic arc tube (narrow tube) to reduce the temperature of glass sealing material
Although there is a method to increase the length of the, the gap between the electric introduction body and the thin tube becomes large, so that the amount of metal halide entering the gap increases. When the amount of metal halide entering the gap increases, for example, when the metal halide entering due to vibration or the like moves and evaporates, the lamp voltage may suddenly increase and the lamp may disappear. Therefore, an object of the present invention is to establish a reliable ceramic metal halide lamp and its manufacturing technique, which suppresses lamp non-lighting without making the tube length unnecessarily long.

[0007]

A ceramic metal halide lamp of the present invention for solving the above-mentioned problems is a translucent ceramic tube provided with a main tube and a thin tube having a diameter smaller than that of the main tube at both ends of the main tube. An electric introduction body having an electrode connected to an end thereof, wherein the electric introduction body uses the main pipe side as an electrode and the electric introduction body is exposed from the thin tube to the outside of the translucent ceramic tube. A ceramic metal halide lamp having a light emitting tube which is inserted into the thin tube and has a fixing portion for hermetically fixing the thin tube and the electric introducing body near the end of the thin tube opposite to the main tube side. And
At least a metal halide is enclosed inside the arc tube, and the fixing portion is provided with a metal holding member outside the thin tube and the electric introducing body, and the electric introducing body and the metal holding member are hermetically sealed. The thin tube and the metal holding member are hermetically fixed by using a glass sealing material.

According to the invention, it is possible to suppress the occurrence of cracks in the fixing portion, reduce the non-lighting of the lamp, and improve the life characteristics of the lamp.

The metal holding member only needs to be capable of covering the thin tube and the electric introduction body at the thin tube end portion, and for example, a cylindrical metal pipe can be used. The shape is preferably a stepped shape or a tapered shape, and is preferably used so that the pipe diameter decreases from the arc tube to the outside. The electricity introducing body is preferably molybdenum, tungsten, or a combination thereof. The molybdenum and tungsten may be a molybdenum alloy and a tungsten alloy, respectively. A welding method can be used for hermetically fixing the electric introducing member and the metal holding member.

By disposing a metal sleeve around the thin tube between the thin tube and the metal holding member, it is possible to more effectively suppress the occurrence of the cracks. The coefficient of thermal expansion of the metal sleeve is preferably a value between the coefficient of thermal expansion of the thin tube and the coefficient of thermal expansion of the metal holding member, and a tubular metal pipe can be used as the shape. In addition, the material of the metal holding member is preferably molybdenum or tungsten, and particularly when a metal sleeve is used, the combination of materials of the metal holding member and the metal sleeve is preferably any one of the following combinations. That is, (a) molybdenum-niobium (b) tungsten-molybdenum (c) tungsten-niobium. The molybdenum, tungsten and niobium may be molybdenum alloy, tungsten alloy and niobium alloy, respectively.

A method of manufacturing a ceramic metal halide lamp according to the present invention, which solves the above-mentioned problems, provides a translucent ceramic tube having a main tube and thin tubes having a diameter smaller than that of the main tube at both ends of the main tube, and an end portion An electric introducer having an electrode connected to the inside of the thin tube so that the electric introducer uses the main tube side as an electrode and the electric introducer is exposed from the thin tube to the outside of the translucent ceramic tube. A metal halide-sealed arc tube having a fixing part for hermetically fixing the thin tube and the electric introducing body in the vicinity of the thin tube end on the side opposite to the main tube side. A method of manufacturing a ceramic metal halide lamp comprising: a step of manufacturing the fixing portion, a step of disposing a metal holding member outside the thin tube and the electric introducing body, the electric introducing body and the metal holding member. Airtightly solid And a step of a step of hermetically fixed to said metallic holding member and the thin tube with a glass sealing material, characterized in comprising.

According to the above invention, it is possible to manufacture a ceramic metal halide lamp which suppresses the generation of cracks in the fixed portion and has good life characteristics, and it is possible to enhance the reliability of the manufacturing technique.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described based on examples with reference to the drawings. FIG. 1 is a view showing a sectional view of an arc tube according to the present invention. An arc tube 10 made of a translucent ceramic tube is composed of a main tube 11 in the central portion and thin tubes 12 attached to both ends thereof. Both ends of the main body 11 are provided with a narrowed portion 13 that is narrowed down via a tapered portion 15 having a curved surface with a radius of curvature R of 2 mm or more. Small diameter part
The thin tube 13 and the thin tube 12 are hermetically joined to each other through a disk 14 made of alumina, and the small-diameter portion 13 has a linear portion between the portion where the disk 14 is attached and the tapered portion 15.
An electric introduction body (17) inserted through the thin tube (12) and connected to the electrode pole core (16) is welded to a metal pipe (18) and is airtightly fixed. The metal pipe 18 covers the thin tube 12, and the gap between the outer surface of the thin tube 12 and the metal pipe 18 is hermetically fixed by the glass sealing material 19. Thus, the fixed portion is formed. A coil 20 is wound around the electrode pole core.

In the arc tube having such a structure, the thin tube 12
A prototype of a lamp with a power consumption of 400 W was manufactured by changing the length of the lamp. The inner diameter of the main pipe 11 is 16 mm, the inner diameter of the small diameter portion 13 is 10 mm, the radius of curvature R of the taper portion is 5 mm, and the inner diameter of the thin pipe 12 at both ends is 2 m.
The length of the thin tube was changed to 20 mm, 15 mm, and 10 mm in m. The electrode pole core 16 has a diameter of 0.9 mm, and the coil 20 is wound around the pole core. The electric introduction body 17 is made of molybdenum and has a diameter of 1.95 mm. The electrode pole core 16 is butt-welded at a position 21. Metal pipe 18 is made of molybdenum
17 is welded to a molybdenum pipe 18 and fixed airtightly. The molybdenum pipe 18 covers the thin tube 12 up to the position 22 and is airtightly fixed by a glass sealing material 19. The glass sealing material uses Al ₂ O ₃ —SiO ₂ —Dy ₂ O ₃ system, and fills the gap between the molybdenum pipe 18 and the thin tube 12. Thus, the arc tube whose both ends are hermetically sealed is filled with mercury, dysprosium iodide, thallium iodide, sodium iodide, cesium iodide and argon as a starting gas.

Next, for the purpose of comparing the characteristics, a sealed structure type lamp similar to that shown in FIG. 2 (b) showing a conventional structure, which does not use a metal pipe, was experimentally manufactured. A cross-sectional view of the arc tube of this lamp is shown in FIG. In addition, the same reference numerals are given to the portions having the same configurations as those of the embodiments showing the present invention. The arc tube 11 made of a translucent ceramic tube is the same as the above ceramic tube. The electrode pole core is inside the outer end of the arc tube of the thin tube 12.
An electric introducer 23 made of a first metal, an electric introducer 27 made of a second metal, and a ceramic sleeve 30 to which 16 is connected are hermetically fixed by a glass sealing material 19. A first coil 20 and a second coil 24 are wound around the electrode pole core 16.
The purpose of the second coil is to release heat from the tip of the electrode to the rear of the electrode and also to position the ceramic sleeve 30.

The electrode pole core 16 has a diameter of 0.9 mm, and a first coil and a second coil are wound around the pole core. The first metal composing the electric lead-in body 24 is made of molybdenum and has a diameter of 0.5 mm and a length.
It is butt welded to the electrode pole core 16 at a position of 3 mm and at a position of 25 mm. 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 a length of 6 m.
m, inner diameter 0.78 mm, outer diameter 1.95. The second metal forming the electric introduction body 27 is fixed by the sealing glass 19 at a position where it is inserted into the thin tube by about 2 mm. Al ₂ O ₃ -SiO ₂ as the sealing glass
-Dy ₂ O ₃ system was used. Sealing glass is about 6 mm from the end of the thin tube
The gap between the electric introducer and the alumina sleeve and the gap between the alumina sleeve and the narrow tube are filled up to the point of entry. Thus, mercury, dysprosium iodide, thallium iodide, sodium iodide, cesium iodide and argon as a starting gas are enclosed in the arc tube whose both ends are sealed.

A lamp was completed by incorporating the above-mentioned two types of arc tubes into a vacuum outer tube, and 10 lamps each were subjected to a life test by vertical lighting. The life test was carried out for up to 6000 hours, and when 2 out of 10 lamps were not lit, that is, when the lit lamps were reduced to 80% of the initial value, the life was judged to be "defective". The light speed maintenance rate was measured up to the point of occurrence of the problem, and the results are shown in Table 1 and FIG.

[0018]

[Table 1]

As can be seen from Table 1 and FIG. 4, in the conventional type, the shorter the narrow tube length, the shorter the problem occurred. All of these had cracks at the sealed portion. On the other hand, in the case of the lamp having the sealing structure of the present invention, no trouble occurred even if the thin tube length was shortened, and no crack was observed in any of the lamps. Although the luminous flux maintenance factor decreases with lighting time, the luminous flux maintenance factor is about 6000 hours after lighting.
Good characteristics of 80% were obtained.

In this embodiment, molybdenum was used for the electric introduction body, but the same effect was obtained even when molybdenum was changed to tungsten. Further, although molybdenum was used for the metal pipe, the same effect was obtained when tungsten was used instead of molybdenum.

Further, as shown in FIG. 5, the metal pipe 18 and the thin tube 1
When the second metal pipe is inserted as a metal sleeve between the two and is airtightly fixed with a glass sealing material, especially when the metal pipe and the second metal pipe shown in Table 2 below are used. With the combination, the effect of suppressing the occurrence of cracks became even more remarkable.

[0022]

[Table 2]

The shape of the metal pipe 18 is shown in FIG.
In the case of a stepped shape in which the pipe diameter decreases toward the outside of the arc tube as shown in (a) or a tapered shape as shown in (b), cracking at the sealing portion is suppressed, and reliability is improved. It turned out to be a structure.

[0024]

As described above, according to the present invention,
It is possible to suppress lamp non-lighting due to cracks in the sealing portion without making the thin tube portion longer than necessary, and to establish a reliable ceramic metal halide lamp and this manufacturing technique.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an arc tube according to the present invention, showing (a) before airtight fixation and (b) after airtight fixation.

FIG. 2 is a cross-sectional view showing the structure of a conventional arc tube,
The figure which shows (a) a cermet type arc tube, (b) a butt-welded type arc tube.

FIG. 3 is a sectional view showing the structure of a conventional arc tube.

FIG. 4 is a diagram showing a life test result.

FIG. 5 is a cross-sectional view showing an embodiment of an arc tube according to the present invention, showing the arc tube provided with a second metal pipe.

FIG. 6 is a cross-sectional view showing an embodiment of an arc tube according to the present invention, showing the arc tube in which the metal holding member has a stepped shape (a) and a tapered shape (b).

[Explanation of symbols]

11 mains 12 thin tubes 17 Electric Introduction 18 metal pipe 19 glass sealing material

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shin Taniguchi             Kyoto Prefecture Kyoto City Minami-ku Kichijoin Nishinosho Inono Babacho             No. 1 within Japan Battery Co., Ltd. F-term (reference) 5C012 JJ01                 5C043 AA07 AA12 CC03 DD11

Claims (6)

[Claims] 1. A translucent ceramic tube having a main tube and a thin tube having a diameter smaller than that of the main tube at both ends of the main tube, and an electric introduction body having electrodes connected to ends thereof, An electric introducer is inserted into the thin tube so that the main body side is an electrode and the electric introducer is exposed from the thin tube to the outside of the translucent ceramic tube. A ceramic metal halide lamp comprising a light emitting tube having a fixing portion for hermetically fixing the thin tube and the electric introduction body in the vicinity of the end of the thin tube, wherein at least a metal halide is enclosed inside the light emitting tube. In the fixing portion, a metal holding member is arranged outside the thin tube and the electric introducing body, the electric introducing body and the metal holding member are hermetically fixed, and the thin tube and the metal holding member are made of glass. Airtightly fixed using a sealing material A ceramic metal halide lamp that features 2. The ceramic metal halide lamp according to claim 1, wherein a metal sleeve is arranged around the thin tube between the thin tube and the metal holding member. 3. The ceramic metal halide lamp according to claim 2, wherein the coefficient of thermal expansion of the metal sleeve is a value between the coefficient of thermal expansion of the thin tube and the coefficient of thermal expansion of the metal holding member. . 4. The material of the metal holding member is molybdenum or tungsten.
The ceramic metal halide lamp according to any one of 1. 5. The combination of materials of the metal holding member and the metal sleeve is the following combination of (a), (b) and (c): 5. The ceramic metal halide lamp according to claim 2, wherein the ceramic metal halide lamp is any one of the above. 6. A translucent ceramic tube having a main tube and a thin tube having a diameter smaller than that of the main tube at both ends of the main tube, and an electric introduction body having an electrode connected to an end thereof. An electric introducer is inserted into the thin tube so that the main body side is an electrode and the electric introducer is exposed from the thin tube to the outside of the translucent ceramic tube. A method for manufacturing a ceramic metal halide lamp having a light-emitting tube in which a metal halide is sealed, having a fixing portion for hermetically fixing the thin tube and the electric introduction body in the vicinity of the end of the thin tube. The manufacturing process of, a step of arranging a metal holding member outside the thin tube and the electric introduction body, a step of airtightly fixing the electric introduction body and the metal holding member, the thin tube and the metal holding member Airtight with the member using glass sealing material And a step of fixing the ceramic metal halide lamp.