JPH01220363A - Ceramic discharge lamp - Google Patents

Abstract

PURPOSE:To prevent the bending of an electrode after the sealing is completed by providing projections on the surrounding portion of a metal pipe and fixing a burner with them when sealing the opening section of a luminous bulb with a disk-shaped blocking body penetrated by the metal pipe supporting the electrode and providing a cross bar to uniformly distribute the molten glass to individual sealing sections on it. CONSTITUTION:The opening section of a luminous tube bulb 1 made of alumina ceramic or the like is blocked by a disk-shaped ceramic blocking body 1 penetrated by a metal pipe 4 supporting an electrode 5, the portion of a through hole 6 penetrated by the metal pipe 4 and the periphery of the blocking body 3 are sealed with glass solder 2. A cross bar 7 which is a split traverse member extended to the end section side across the metal pipe 4 is provided on the blocking body 3 to uniformly distribute the solder 2 to individual sealing sections, a pair of projections 8 are formed face to face on the blocking body 3 perpendicularly to the extended section at the portion of the bar 7 pinching the metal pipe 4. The metal pipe can be thereby supported vertically when it is sealed, and the electrode is not inclined.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a ceramic discharge lamp using an arc tube bulb made of translucent ceramic.

(Prior Art) Ceramic discharge lamps, such as high-pressure sodium lamps, which use translucent ceramic as an arc tube bulb are known as lamps with extremely high luminous efficiency. In the arc tube bulb of such a ceramic discharge lamp, since the ceramic is a high melting point material, the tube end cannot be crushed and sealed by heating and softening as in the case of a quartz glass arc tube bulb. Metals with thermal expansion coefficients similar to those of ceramics, such as niobium for alumina ceramics.

Using a hat-shaped, cap-shaped, or plate-shaped closure body made of a high melting point metal such as mental or similar ceramic, seal the end of the tube via a sealing material such as glass solder,
This closure body holds an electrode.

For example, Japanese Patent Publication No. 59-44745 (Conventional Example 1) K
4 shows a ceramic discharge lamp having a tube end sealing structure as shown in FIG. In the figure, (1) is an arc tube bulb made of, for example, translucent alumina ceramic, and (3) is a disc-shaped ceramic closure formed with a smaller diameter than the inner diameter of the arc tube bulb (1), and its outer periphery is a light-emitting Pipe valve (1)
The tube end is hermetically sealed to the inner circumferential surface of the tube via a glass solder (2). (9) is a lead-in wire, which is airtightly inserted through the through hole (6) provided in the center of the closure body (3) via the glass solder (2), and the electrode (5) is held at the tip of the lead-in wire. Ru. (7) is a transverse member (cross bar) provided on the outer surface of the closure body (3), the center part of which is fixed to the lead-in wire (9), and both ends of the cross bar (1) fixed to the tube end surface. Although not shown, when the glass solder molded body placed on the transverse member (7) is heated and melted.

This molten glass solder is applied to each portion to be sealed, that is, the outer peripheral surface of the closure body through hole (6) and the closure body (3), and the arc tube bulb (
It also fulfills the role of distributing it to the gap between the inner wall surface of the tube end and the tube end (1). Such a structure has a great practical effect and has been praised because the above-mentioned portions to be sealed can be sealed simultaneously in one step.

However, even an arc tube having such a sealing structure has the following problems. Namely.

When a filler material, such as sodium amalgam, accumulates at the end of the arc tube, the glass solder (2) exposed inside the tube comes into contact with the sodium amalgam, causing two reactions, and as this reaction progresses, the VL rise over the lifespan gradually increases. This has the disadvantage that the lamp tends to have a short lifespan.

In order to deal with these drawbacks, it is also known to use a metal tube in place of the lead-in wire (4) in Conventional Example 1.

FIG. 5 shows the tube end sealing structure of another conventional example (Conventional Example 2), in which (1) is an arc tube bulb, and (3A) is a cap-shaped ceramic cap having a protruding edge (3Aa). The protruding edge (3Aa) of the closure is hermetically sealed to the end face of the arc tube bulb (1) via a glass solder (2). (4) is a metal tube made of, for example, niobium, which is hermetically inserted through the through hole (6) provided in the center of the above-mentioned closure body (3 people) via the glass solder (2), and has an electrode ( 5
) is supported. (8) is a convex portion formed on the outer periphery of the metal tube (4), which is formed when the proximal end of the electrode (5) is crimped and fixed. With this configuration, most of the inclusions, such as sodium amalgam, accumulate in the metal tube (4), so the contact between the inclusions and the glass solder (2), which was the case in the conventional example, can be reduced. There are advantages.

However, such a tube end sealing structure has a problem in the sealing process. FIG. 6 shows an explanatory diagram of the sealing process. Nine arc tube bulbs (1) are supported so that the unsealed opening side is positioned downward, and a cap-shaped closure body (three people) is placed on the opening. and the through hole (6) of this closure body (3A)
a metal tube (4) through which the electrode (5) is fixed and supported at one end; and *l'2o3. Two ring-shaped glass solder molded bodies (2A) made by compression molding Cab, BaO, etc.
) and (2B) are arranged as shown in the figure. In this arrangement, if the metal tube (4) is supported by a support jig, the closure body (3A) is locked by the protrusion (8) of the metal tube (4) and is prevented from falling. next.

For example, if the glass solder molded bodies (2A) and (2B) are heated in an atmosphere such as an inert gas, one of the glass solder molded bodies (2 people) melts and flows into the 9 through hole (6). The metal tube (4) is hermetically sealed, and the other glass solder molded body (2B) is melted to connect the arc tube bulb (1) and the closing body (3).
A) and hermetically sealed.

However, according to such a manufacturing method.

It is necessary to use a cap-shaped closure body with a more complicated shape than a disc-shaped one, and to use two large and small glass solder molded bodies, which increases the cost and also requires two glass solder molded bodies. If it is not heated and melted evenly, there are problems in terms of workability, such as the airtightness of the two sealed parts not being uniform.

Furthermore, tube end seal structures as shown in FIGS. 7 and 8 have also been considered. Incidentally, the same parts as those in the conventional example described above are given the same reference numerals, and the explanation thereof will be omitted. In this case, the shape of the closing body (3) may be a disk shape, and only one glass solder molded body (not shown) is placed on the outer surface of the closing body (3) during the sealing process. With the help of the transverse member (7), the molten glass solder is evenly applied to the two areas to be sealed: the through hole of the closing body (6) and the gap between the closing body (3) and the arc tube bulb (1). Since it is distributed to
This is preferable from both cost and workability points of view. However, this method also has the following problems. In other words, during the sealing process, a transverse member whose role is to evenly distribute the molten glass solder for sealing to each sealing part (the force is normally applied to the center part of the molten glass solder to the outer peripheral part of the metal tube (4) as shown in FIG. Since it is welded and fixed on one side, the metal tube (4) inserted through the closure body through hole (6) is unbalanced and tilts.

For this reason, the electrode (5) supported by the metal tube (4) K will naturally end up being sealed and fixed in a tilted position from its normal position, which will adversely affect the reliability of the sealed part and the lamp characteristics. Sometimes.

(Problems to be Solved by the Invention) As described above, the conventional tube end sealing structure has the disadvantage that the glass solder and the filler, such as sodium amalgam, come into contact and react, resulting in a short life.

On the other hand, by using a metal tube as an electrode support member and storing excess filler in the metal tube, contact reaction with the glass solder is prevented, and cost and workability are improved by using a two-disk-shaped closing body. This method has the disadvantage that the electrodes tend to be bent due to the effect of the transverse member provided for uniformly distributing the molten glass solder.

Therefore, the present invention solves the above-mentioned conventional drawbacks, and even if a disk-shaped blocker or metal tube is used, the electrode will be bent and K
The purpose is to provide a ceramic discharge lamp.

[Structure of the invention]

(Means for Solving the Problems) The ceramic discharge lamp of the present invention has a disc-shaped ceramic closure body that fits into the opening of an arc tube bulb made of translucent ceramic through a glass solder. Seal with
An electrode is supported by a metal tube that is hermetically inserted through the through hole of the closure body through a glass solder, and on the outer surface of the closure body, the center part surrounds the metal tube, and the two ends are the end faces of the arc tube bulb. A transverse member made of a metal wire extending to K is disposed, protrusions are provided at opposing positions on the outer peripheral surface of the metal tube, and the transverse member is held between these protrusions and the outer surface of the closure body. It is composed of

(Function) According to the above configuration, the shape of the transverse member, which plays the role of evenly distributing molten glass solder to each sealing part during the tube end sealing process, is such that the central part surrounds and supports the metal tube. In addition, since the transverse member is held between the protrusions provided at opposing positions on the outer peripheral surface of the metal tube and the outer surface of the closure body, there is no need to weld the metal pipe to the transverse member, and
Since it can be supported vertically during the tube end sealing process, bending (tilting) of the electrode supported by the metal tube is also prevented.

In addition, since the above-mentioned sealing process requires the use of only one glass solder molded body, it is preferable from the viewpoint of cost and workability.
Furthermore, by using a metal tube, excess inclusions can be collected in the metal tube, so that contact reaction between the inclusions and the glass solder can be suppressed.

(Example) The present invention will be described in detail below with reference to an example shown in two drawings. FIG. 1 shows one end of the arc tube of an embodiment of the high-pressure sodium lamp according to the present invention, (1) is an arc tube bulb made of a translucent ceramic, such as alumina ceramic, and the opening thereof is made of, for example, alumina or calcia. It is hermetically sealed by a disk-shaped closing body (3) made of ceramic such as alumina ceramic and having a size that fits into the opening through a glass solder (2) mainly composed of magnesia or the like. (4) is a metal tube made of niobium, for example, and serves as a power supply to the electrode (5) supported at one end thereof, and also as an exhaust pipe if necessary.

This metal tube (4) is connected to the through hole (6) provided in the center of the closure body (3) with the same glass solder (2) as above.
), and the inner end (4a) of the two arc tubes is expanded and brought into contact with the opening periphery of the closure body through hole (6). ), and also restricts the protruding length of the electrode (5) or prevents the molten glass solder flowing into the closure through-hole (6) from flowing out of the through-hole (6).

(7) is a transverse member (crossbar) made of a metal wire such as niobium wire, which is arranged on the outer surface of the closure body (3), and its central part (7a) surrounds the metal tube (4) and is
Both end portions (7b) and (7b) are formed so as to extend to the end surface (1a) of the arc tube bulb (1), respectively.

Furthermore, convex portions (8) and (8) are formed at opposing positions on the outer peripheral surface of the portion of the metal tube (4) that protrudes outward from the outer surface of the closure body (3a), respectively. These convex portions (8), (8) in this embodiment are used to press and fix the base end (5a) of the electrode (5) to the metal tube (4).
It is a knob portion that is generated when the opposing tube wall portions of the metal tube (4) are squeezed, and the transverse member (7) has the above-mentioned convex portions (8),
(8) and the outer surface of the closure body (3a).

Note that a predetermined amount of xenon gas and sodium amalgam are sealed in the arc tube 9.

In the high-pressure sodium lamp arc tube with such a configuration, the tube end sealing process does not require the transverse member (7) to be in bath contact with the metal tube (4), and the center portion (7a) is in contact with the metal tube (4). Just by inserting the electrode, the metal tube (4) that supports the electrode will be crimped and clamped to the outer surface (3a) of the closure body by its own weight, which improves productivity and eliminates the need for the transverse member of the metal tube (4). (7) also does not occur, and therefore the metal tube (4
) can also maintain its normal position to complete the sealing process.

In addition, the transverse member (7) is attached to the metal tube (4) with a protrusion (8),
Unlike in the case where (8) is not provided and the metal tube is held only by frictional force using the spring of the transverse member, the metal tube does not fall due to the high temperature during sealing and it is not possible to maintain a normal device.

Note that the transverse member (7) is not limited to the above-mentioned shape; in short, its central portion surrounds the metal tube (4).

It is only necessary to form it so that both ends thereof extend to the end face (1a) of the arc tube bulb (1).

For example, FIG. 3 (a plan view seen from the outer surface side of the closure body (3)) shows a modification thereof.

Further, the present invention is not limited to the above embodiments, but can be applied to other ceramic discharge lamps such as metal halide lamps in which a light-transmitting ceramic arc tube bulb is sealed with a ceramic closure.

〔Effect of the invention〕

As described in detail above, according to the structure of the present invention, a disc-shaped ceramic closing body that fits into the opening of one arc tube bulb is used to seal the opening, and a through hole provided in this closing body is used. Even if the electrode is supported by the metal tube inserted through the sealing body, and a transverse member is provided on the outer surface of the closure body to evenly distribute the glass solder to each sealing part during the sealing process, the reliability of the sealing part may be reduced. It is possible to obtain a ceramic discharge lamp with a high resistance and no bending of the electrodes upon completion of the sealing process.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of one end side of a high-pressure IJ lamp luminous tube which is an embodiment of the present invention, Fig. 2 is a plan view from the outer surface side of the closing body, and Fig. 3 is a cross-sectional view of the transverse member. An explanatory diagram of a modified example, FIG. 4 is a longitudinal cross-sectional view of one end side of the arc tube of conventional example 1,
Fig. 5 is a longitudinal sectional view of one end side of the arc tube of conventional example 2, Fig. 6 is an explanatory diagram of the manufacturing process, Fig. 7 is a longitudinal sectional view of one end side of the arc tube of conventional example 3, and Fig. 8 is also closed. Each shows a plan view from the outer surface side of the body. (1)... Arc tube bulb. (1a)... End face of arc tube bulb. (2)...Glass solder, (3)...
Obstruction body. (4)...Metal tube, (5)...Electrode. (6)...through hole, (7)...transverse member. (7a)... Central part of the transverse member. (7b)... End of the transverse member. (8)...Protrusion.

Claims (1)

[Claims] The opening of an arc tube bulb made of translucent ceramic is sealed with a disk-shaped ceramic closing body that fits into the opening through glass solder, and the through hole provided in the closing body is sealed through glass solder. In a ceramic discharge lamp in which an electrode is supported by a metal tube that is hermetically inserted through a metal tube, a metal tube is provided on the outer surface of the closing body, the center part of which surrounds the metal tube, and both ends of which extend to the end faces of the arc tube bulb. A ceramic discharge lamp characterized in that a transverse member made of wire is disposed, and the transverse member is held between protrusions provided at opposing positions on the outer peripheral surface of the metal tube and the outer surface of the closure body. .