JP2000100388A - Discharge lamp made of ceramic and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp made of a ceramic easily manufactured despite its having sleeves, and having stable working characteristics by disposing each sleeve made of a ceramic around an electrode rod put through a sealed tube part, and fastening the outer end part of the sleeve to a sealing member. SOLUTION: An outer end face of each of sleeves 35 made of a ceramic is fastened integrally to an inner end face of a sealing member 37 in each of sealed tube parts 32 of a discharge container 30. The sleeve 35 is shaped so that its outside diameter fits to the inside diameter of the sealed tube part 32, while its inside diameter fits to an outside diameter of each electrode rod 34. Preferably, the difference between the outside diameter of the sleeve 35 and the inside diameter of the sealed tube part 32 is small, more specifically, 0.12 mm or less. The sleeve 35 is jointed to the sealing member 37 by a method, such as sintering or laser welding. As the material for making up the sleeve 35, a material having a linear expansion coefficient which is the same as or similar to that of the discharge container 30 and of the sealing member 37 is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic discharge lamp such as a high-pressure discharge lamp and a metal halide lamp, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a ceramic discharge lamp, in a process of forming a hermetically sealed structure in a sealing tube portion, the sealing tube portion cannot be melted and deformed. By filling the gap between the sealed electrode frit glass with the sealing frit glass, a hermetic sealing structure is formed.

However, frit glass has a heat-resistant temperature of about 840 ° C., which is not sufficiently high, so that it is necessary to avoid overheating when the discharge lamp is turned on. For this reason, as shown in FIG. 5, in the sealing tube portion 12 of the ceramic discharge lamp, the central portion of the arc tube portion 11 that becomes extremely high when lit,
In order to separate the frit sealing body 17 from the hermetic sealing area A formed by being injected into the outer end side portion of the sealing tube part 12, an appropriate length following the arc tube part 11 is used. In the temperature buffering region R, the sealing tube 12 and the discharge electrode 13 are provided.
(Hereinafter, referred to as “dead space”) G that communicates with the arc tube interior space S between the electrode rod 14 and the electrode rod 14 having a tip.
Is inevitably formed. In addition, 16 is the electrode rod 1
4 is an external lead rod connected to the external lead 4. However, when the dead space exists, the enclosed mercury enters the space and is condensed, so that the operating characteristics of the discharge lamp vary. In order to prevent this, the ceramic sleeve 15 is positioned in the dead space.
Are arranged in a state where the electrode rod is inserted.

FIG. 6 is an enlarged view of a sealing tube portion of an example of a ceramic discharge lamp in which such a sleeve is provided and fixed in the sealing tube portion. In this example, the sleeve 26 is arranged in the sealing tube 21 so that the large-diameter electrode rod portion 23B integrally joined to the small-diameter electrode rod portion 23A having the discharge electrode 22 at the tip end is inserted. The sleeve fixing coil 24 is wound around the large-diameter electrode rod portion 23B and fixed at a position close to the inner end surface side of the sleeve 26, thereby preventing the sleeve 26 from moving. Then, a sealing member 25 made of cermet is sealed to the outer end surface of the sealing tube portion 21 by a frit sealing body 27 to form an airtight sealing structure. Also, the sealing member 25
The end of an external lead rod 28 extending outward is embedded in the outer end side portion of.

However, as described above, the configuration in which the sleeve 26 is held by the sleeve fixing coil 24 wound on the electrode bar not only complicates the manufacturing operation, but also
During operation, a phenomenon (back arc phenomenon) occurs in which discharge occurs from the sleeve fixing coil 24, and as a result, the arc tube portion or the sealing tube portion 21 reaching the vicinity of the sleeve fixing coil 24 is locally heated and is damaged. Problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a simple and stable manufacturing method having a sleeve in a sealing tube portion. An object of the present invention is to provide a ceramic discharge lamp having operating characteristics. It is another object of the present invention to provide a method for manufacturing the above-mentioned ceramic discharge lamp.

[0007]

According to the present invention, there is provided a ceramic discharge lamp comprising a discharge vessel having an arc tube portion made of translucent ceramics and a sealed tube portion connected to the arc tube portion. A sealing member in which a pair of discharge electrodes are opposed to each other in an arc tube portion, and an electrode rod having the discharge electrode at a distal end portion is located in the sealing tube portion, and a base end portion of the electrode rod is fixed. Is a ceramic discharge lamp sealed in a sealing tube portion by a frit sealing body, in the sealing tube portion, a ceramic sleeve is disposed in a state where an electrode rod is inserted, An outer end portion is fixed to the sealing member.

Further, in the above-mentioned ceramic discharge lamp, the outer end of the sleeve is fixed to the sealing member while being inserted into a recess formed in the end face of the sealing member. And Further, in the above ceramic discharge lamp, the outer end of the sleeve is fixed to the sealing member by sintering.

The method of manufacturing a ceramic discharge lamp according to the present invention is directed to a method of manufacturing a ceramic discharge lamp, wherein the electrode rod having a discharge electrode at its tip is fixed to a sealing member having the electrode rod inserted therethrough. An electrode structure having an end portion fixed to a discharge vessel material having an arc tube portion made of translucent ceramics and a sealing tube portion connected to the arc tube portion, wherein the discharge electrode is an arc tube And a step of sealing the sealing tube portion and the sealing member of the discharge vessel with a frit sealing body in a state where the sealing tube portion and the sleeve are positioned so as to be positioned within the sealing tube portion. .

[0010]

According to the above construction, since the sleeve disposed in the dead space in the sealing tube portion is integrally fixed to the sealing member, it is easy to manufacture and has stable operation characteristics. A ceramic discharge lamp having a long service life without back arc phenomenon can be obtained. Further, for the same reason, it is possible to manufacture a ceramic discharge lamp having a sleeve in a state where the electrode rod is inserted into the sealing tube portion by an extremely simple operation.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory sectional view showing an example of the ceramic discharge lamp of the present invention. The discharge vessel 30 constituting the ceramic discharge lamp of this example has an elliptical spherical arc tube part 31 and a cylindrical sealing tube part 32 continuously extending outward from both ends of the arc tube part 31. And is formed of translucent ceramics.
Here, as the ceramics constituting the discharge vessel 30, a translucent polycrystalline alumina, a translucent yttrium-aluminum-garnet polycrystalline, or a translucent polycrystalline yttria can be used. And polycrystalline alumina are particularly preferred. The maximum outer diameter of the arc tube part 31 is 8.7 to 11.0 mm, and the inner volume is 0.4 to 0.75 cm.
It is assumed to be ³ . The outer diameter of the sealing tube 32 is 2.0 to 2.
6mm, inner diameter 0.6-1.0mm, length 34-40
mm.

A pair of discharge electrodes 33 are opposed to each other in the arc tube portion 31 of the discharge vessel 30.
3 is formed by winding a metal coil made of, for example, molybdenum around the tip of an electrode rod 34 made of, for example, tungsten, which is arranged to extend along the tube axis from the inside of the sealing tube part 32 to the arc tube part 31. Have been. Electrode rod 34
Is fixed to the inner end portion of a columnar conductive sealing member 37 located in the sealing tube portion 32. The outer end portion of the sealing member 37 has The end of the external lead rod 36 extending in the direction is fixed.

The material of the sealing member 37 includes, for example, an alumina component, a silica component, a linear expansion coefficient adjusting component which is a metal oxide other than alumina and silica, and a metal component having a smaller linear expansion coefficient than alumina. A cermet having a coefficient of linear expansion equal to or close to that of the transparent ceramics suitably used as the material of the discharge vessel 30 is used. Specific examples thereof include an alumina-magnesium oxide-molybdenum-silica-based cermet and an alumina-dysprosium oxide-molybdenum-silica-based cermet. The content ratio of each component is, for example, 15 to 60% by volume of an alumina component, 5 to 30% by volume of a silica component, 5 to 40% by volume of a linear expansion coefficient adjusting component which is a metal oxide other than alumina and silica, and The metal component having a small coefficient of linear expansion is 30 to 60% by volume. Cermet is
It is preferable that a silica component is contained, and the inclusion of the silica component makes it easy to adhere to a sleeve described later.

In the ceramic discharge lamp of this embodiment, the entirety of the sealing member 37 is inserted into the outer end portion of the sealing tube 32, and the outer end of the sealing tube 32 is frit sealed. The provision of the attachment body 38 forms an airtight sealing structure. Here, as a material of the frit sealing body 38, a rare earth oxide-alumina-silica-based material or the like can be used.

In the sealed tube portion 32 of the discharge vessel 30, a sleeve 35 made of ceramic is covered with an electrode rod 34.
Are inserted and the outer end surface of the sleeve 35 is integrally fixed to the inner end surface of the sealing member 37. As a material of the sleeve 35, a ceramic having a coefficient of linear expansion equivalent to or close to that of the light-transmitting ceramic forming the discharge vessel 30, for example, a light-transmitting alumina crystal,
A translucent yttrium-aluminum-garnet polycrystal, a translucent yttria polycrystal, or the like can be used. The length of the sleeve 35 is, for example, 4 to 6 mm, depending on the length of the sealing tube 32. Sleeve 35
It is desirable that each of the electrodes has a shape whose outer diameter matches the inner diameter of the sealing tube portion 32 and whose inner diameter matches the outer diameter of the electrode rod 34. In particular, it is preferable that the difference between the outer diameter of the sleeve 35 and the inner diameter of the sealing tube part 32 is small, specifically, 0.1.
It is desirably 2 mm or less. As a result, the gap between the two becomes sufficiently narrow, and it becomes possible to reduce the amount of the filling material that enters and condenses.

The joint between the sleeve 35 and the sealing member 37 is as follows.
For example, it can be performed by a method such as sintering or laser welding. By using a material having the same or similar linear expansion coefficient as the material of the discharge vessel 30 and the sealing member 37 as a material forming the sleeve 35, the occurrence of cracks due to a difference in linear expansion coefficient in the joined body is generated. Can be prevented, and sufficient strength can be obtained.

According to the ceramic discharge lamp constructed as described above, the dead space can be made extremely small by the sleeve 35 which is practically held integrally with the discharge vessel 30, and the back arc phenomenon occurs. Therefore, sufficiently good operating characteristics can be stably obtained.

FIG. 2 shows another example of the ceramic discharge lamp of the present invention. In this discharge lamp, the electrode rod is composed of a small-diameter electrode rod portion 41 and a large-diameter electrode rod portion 42, and a discharge electrode 33 is formed by winding a metal coil around the tip of the small-diameter electrode rod portion 41. I have. The base end of the large-diameter electrode rod portion 42 is fixed to an inner end side portion of the sealing member 37 located outside the sealing tube 32. The outer end face of the sleeve 35 in which the large-diameter electrode rod portion 42 is inserted is integrally fixed to the inner end face of the sealing member 37, and the sleeve 35 is sealed with the outer end face of the sealing tube 32. The sealing member 37 is frit-welded to the outer end surface of the sealing tube 32 by the frit sealing body 38 filled between the stopper member 37 and the inner end surface, thereby forming an airtight sealing structure. .

FIG. 3 shows still another example of the ceramic discharge lamp of the present invention. In the configuration of this discharge lamp,
A concave portion is formed in the inner end surface portion of the sealing member 37 located outside the sealing tube portion 32, and a sleeve in which the large-diameter electrode rod portion 42 is inserted is disposed in the concave portion. The outer end of the member 35 is received, and is fixed to the sealing member 37 in this state. The base end of the large-diameter electrode rod portion 42 is fixed in a state protruding outward from the sleeve 35 and buried in the sealing member 37. And the sealing structure of the discharge vessel,
The configuration is similar to that of FIG. In the discharge lamp having such a configuration, the same operation and effect as the example of FIG.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described example, and various changes can be made to the specific configuration of each unit. For example, a small-diameter electrode rod portion 4 constituting an electrode rod
The material 1 and the large-diameter electrode rod portion 42 may be made of different materials from each other, and for example, those joined by a method such as butt welding can be used. Actually, it is preferable to use, for example, tungsten as a material of the small-diameter electrode rod portion 41, and to use, for example, molybdenum as a material of the large-diameter electrode rod portion 42, whereby a large heat resistance is obtained for the small-diameter electrode rod portion 41, Good bonding properties to the sealing member 37 can be obtained for the large-diameter electrode rod portion 42. Further, the electrode rod may be configured to penetrate the sealing member. In that case, the outer end of the electrode rod functions as an external lead as it is, and the sealing member is an insulating member. There may be.

The ceramic discharge lamp of the present invention having the structure shown in FIG. 1 is manufactured as follows. That is,
First, as shown in FIG. 4, an electrode rod 34 having a discharge electrode 33 wound with a metal coil at a tip portion, and a sleeve 35.
Then, an electrode structure 50 including the sealing member 37 and the external lead bar 36 is manufactured. The base end of the electrode rod 34 is fixed to one end of a cylindrical sealing member 37, and the other end of the sealing member 37 is fixed to one end of an external lead bar 36. Further, one end surface of a sleeve 35 in which the electrode rod 34 is inserted is integrally fixed to an end surface of one end of the sealing member 37 to which the electrode rod 34 is fixed.

The joint between the sleeve 35 and the sealing member 37 is as follows.
As described above, for example, sintering can be performed by a method such as welding with a laser. In the case of joining by sintering, a temporary sintered body of a cermet or a ceramic member used as the sealing member 37 is formed. The electrode rod 3
4 and the external lead rod 36 are inserted and arranged, and the sleeve 35 is brought into contact with the end face of the temporary sintered body or inserted into the recess, and the final sintering process is performed in this state, so that the main A method in which sintering is achieved and the electrode rod 34, the external lead rod 36, and the sleeve 35 are integrally fixed to the main sintered body can be preferably used. As a sintering condition, in the cermet preliminary sintering process, for example, heating is performed at 1200 ° C. for 30 minutes. Further, in the main sintering process of the sleeve 35 and the sealing member obtained by the preliminary sintering, the sleeve 35 is heated at, for example, 1700 ° C. for 15 minutes.

The electrode structure 50 thus obtained
With respect to a discharge vessel material having an arc tube portion made of translucent ceramics and a sealing tube portion connected to the arc tube portion, the discharge electrode 33 is located in the arc tube portion 31 and the sleeve 35 After being arranged so as to be located in the sealing tube portion 32,
By filling the outer end side portion of the sealing tube portion 32 from which the external lead rod 36 projects with molten frit glass, the frit sealing body 38 having the configuration shown in FIG. An airtight sealing structure in which the electrode structure 50 is airtightly fixed is formed.

According to the method of manufacturing a ceramic discharge lamp as described above, the electrode structure 50 is formed in which the sleeve 35 is integrated with the discharge electrode 33, the electrode rod 34, the sealing member 37, and the external lead rod 36. However, since it is only necessary to dispose this in a sealing tube portion of a predetermined discharge vessel material and seal the sealing tube portion and the sealing member, no special consideration is required for handling the sleeve 35. The required ceramic discharge lamp can be manufactured with very simple operations.

[0025]

As described above, according to the ceramic discharge lamp of the present invention, since the sleeve disposed in the dead space in the sealing tube is integrally fixed to the sealing member, the production is easy. Thus, a ceramic discharge lamp having stable operating characteristics, no back arc phenomenon, and a long service life can be obtained. Further, for the same reason, it is possible to manufacture a ceramic discharge lamp having a sleeve in a state where the electrode rod is inserted into the sealing tube portion by an extremely simple operation.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing one example of a ceramic discharge lamp of the present invention.

FIG. 2 is an explanatory sectional view showing another example of the ceramic discharge lamp of the present invention.

FIG. 3 is an explanatory sectional view showing still another example of the ceramic discharge lamp of the present invention.

FIG. 4 is a sectional view for explaining an electrode structure in the ceramic discharge lamp of FIG. 1;

FIG. 5 is a sectional view for explaining a temperature buffer region in a sealing tube portion of the ceramic discharge lamp.

FIG. 6 is an enlarged sectional view of a sealing tube part in an example of a ceramic discharge lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Arc tube part 12 Seal tube part 13 Discharge electrode 14 Electrode rod 15 Sleeve 16 External lead wire 17 Frit sealing body A Hermetic sealing area R Temperature buffering area S Arc tube interior space G Dead space 21 Sealing tube part 22 Electrode 23A Small-diameter electrode rod part 23B Large-diameter electrode rod part 24 Sleeve fixing coil 25 Sealing member 26 Sleeve 27 Frit sealing body 28 External lead rod 30 Discharge vessel 31 Emission tube part 32 Sealing tube part 33 Discharge electrode 34 Electrode rod 35 Sleeve 36 external lead rod 37 sealing member 38 frit sealing body 41 small diameter electrode rod part 42 large diameter electrode rod part 50 electrode structure

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mitsuru Ikeuchi 1194 Sado, Bessho-cho, Himeji-shi, Hyogo USHIO Electric Co., Ltd. F-term (reference) 5C012 AA08 JJ01 JJ02 5C043 CC03 CD01 DD11 DD15

Claims (4)

[Claims] 1. A discharge vessel having an arc tube portion made of translucent ceramics and a sealing tube portion connected to the arc tube portion, and a pair of discharge electrodes are arranged in the arc tube portion to face each other. At the same time, an electrode rod having the discharge electrode at the distal end is located in the sealing tube portion, and a sealing member having a base end portion of the electrode rod fixed thereto is sealed to the sealing tube portion by a frit sealing body. A ceramic discharge lamp that is stopped, wherein a ceramic sleeve is disposed in the sealing tube portion with an electrode rod inserted therein, and an outer end of the sleeve is fixed to the sealing member. A discharge lamp made of ceramic, characterized in that: 2. The method according to claim 1, wherein the outer end of the sleeve is fixed to the sealing member while being inserted into a recess formed in an end surface of the sealing member. Ceramic discharge lamp. 3. The ceramic discharge lamp according to claim 1, wherein an outer end of the sleeve is fixed to the sealing member by sintering. 4. An electrode structure in which an outer end of a ceramic sleeve in which the electrode rod is inserted is fixed to a sealing member to which an electrode rod having a discharge electrode at the tip is fixed. With respect to a discharge vessel material having an arc tube portion made of a translucent ceramic and a sealing tube portion connected to the arc tube portion, the discharge electrode is located in the arc tube portion, and the sleeve is sealed. A method for manufacturing a ceramic discharge lamp, comprising a step of sealing a sealing tube portion and a sealing member of a discharge vessel with a frit sealing body in a state where the sealing tube portion is arranged in a tube portion.