JPH05334995A - Metallic vapor electric discharge lamp - Google Patents

Abstract

PURPOSE:To enable sealing of a light emitting tube pipe without evaporating materials sealed therein by reducing the diameter of the blocking surface of a small-diameter hole blocking cap which faces a small diameter hole formed in a pipe blocking cap, and making smaller glass frits provided for sealing the blocking surface, thus permitting the glass frits to be melted and solidified in a short time to promptly seal the light emitting tube pipe. CONSTITUTION:A metallic vapor electric discharge lamp has a light emitting tube pipe 112 made from monocrystal alumina and pipe blocking caps 114 in the form of a projecting pole made from alumina and having a small--diameter through hole smaller than the bore of the light emitting tube pipe 112. The metallic vapor electric discharge lamp further has small-diameterhole blocking cape 130 made from conductive cermet, and halogen resistant glass frit 122 provided in a gap in that portion of the small-diameter hole blocking cap 130 which fits with the pipe blocking cap 114.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal vapor discharge lamp, and more particularly to an improvement in the structure of a closing body provided at both ends of an arc tube.

[0002]

2. Description of the Related Art Recently, a discharge lamp has been used as a light source of a projection optical system such as a liquid crystal projection, and particularly, a metal vapor discharge lamp excellent in luminous efficiency characteristics and RGB luminous balance is drawing attention. The image light source for the liquid crystal projection has a wavelength of 600 n, which emits light in the red region.
It is desirable that light emission of m or more is efficiently performed. For this reason, metal vapor discharge lamps containing lithium as an enclosure in the arc tube have been developed.

In the arc tube containing the lithium,
It is known that when the arc tube is made of quartz, when the arc tube is operated at high temperature and high pressure, lithium is extracted out of the tube, which causes a decrease in red light. Therefore, it has been considered to prevent the lithium from leaking out of the tube by using translucent alumina, which is used as an arc tube material of a high-pressure sodium lamp, instead of the quartz as the arc tube material. .. However, general translucent alumina is
Since the apparent light source becomes large due to the strong diffusion of light, it is difficult to efficiently enter the light flux emitted from the light source by the reflector such as a paraboloid into the projection optical system. Is inappropriate.

For this reason, an arc tube having a good linear transmissivity that does not cause the diffusion of light so much is suitable as an image light source, and an arc tube made of single crystal alumina among the transmissive aluminas that satisfies the above conditions. A discharge lamp using is being studied. FIG. 4 shows a discharge lamp using an arc tube pipe made of the single crystal alumina. The discharge lamp 10 shown in the figure has a cylindrical arc tube pipe 12 made of single-crystal alumina with both ends open, and a pipe closing cap 14a made of a conductive cermet fitted at both ends of the arc tube pipe 12. , 14b and the pipe closing caps 14a, 14b are respectively planted inside,
An electrode mandrel 18 having a coil 16 wound around the tip thereof and an external lead bar 20 implanted outside the pipe closing cap 14 are provided. In addition, the gap between the both ends of the arc tube pipe 12 and the pipe closing cap 14 is
It is sealed by a halogen-resistant glass frit 22, and the inside of the arc tube 12 is hermetically sealed.

[0005]

By the way, in the method of molding the discharge lamp 10 shown in FIG. 4, the pipe closing cap 14b is previously sealed by the glass frit 22 in one opening of the arc tube pipe 12. And arc tube 1
Insert an enclosure containing lithium or the like from the other opening of 2,
The pipe closing cap 14a is sealed with the glass frit 22 in the other opening in a rare gas atmosphere.

When the pipe closing cap 14a is sealed to the opening of the arc tube pipe 12 with the glass frit 22, the pipe closing cap 14a and the arc tube 1 are sealed.
Glass frit 22 provided in a fitting portion with the opening of 2
The molded body of is melted by heating, and the molten glass frit 22
Is permeated into the entire gap of the fitting portion and then cooled and solidified. Here, the glass frit 22 must be rapidly melted and solidified. That is, when the glass frit 22 is heated and melted, since the arc tube 12 is a highly transparent single crystal alumina, the radiant heat of the heating section is rapidly transferred to the place where the enclosed material of the arc tube 12 is retained, This is because the temperature of the inclusions rises and evaporates outside the arc tube pipe 12 before the glass frit 22 solidifies.
The evaporation of the inclusions is more likely to occur as the arc tube length of the arc tube 12 becomes shorter. Therefore, in the arc tube 12 having the short arc tube length, the heating and cooling must be performed rapidly.

However, if the diameter of the arc tube pipe 12 is large, naturally the molded body of the glass frit 22 provided in the fitting portion with the pipe closing cap 14a also becomes large, and it takes time to melt and solidify the glass frit 22. Will end up. Further, if the glass frit 22 is heated and cooled forcibly and rapidly, the arc tube 12 is also rapidly heated and quenched, so that the arc tube 12 made of single crystal alumina is cracked. Further, the pipe closing cap 14 is made of a conductive cermet made of alumina and tungsten, and the ratio of the alumina and the dungsten is uneven depending on the location, so that the thermal shock resistance is poor. Therefore, when the diameter of the arc tube pipe 12 is large, the diameter of the pipe closing cap 14 is also large, and when the rapid heating / cooling is performed, the pipe closing cap 14 is increased.
There was also a problem that cracks were likely to occur.

[0008] The arc tube pipe 12 has a shape in which both ends are squeezed and the diameter of the opening is made small so that the glass frit 22 can be melted and solidified quickly and the pipe closing cap 14 can be prevented from being cracked. As can be seen, since the single crystal alumina, which is the material of the arc tube pipe 12, has a low degree of freedom in molding, it is impossible to mold the both end portions into a narrowed shape. The present invention has been made in view of the above-mentioned problems of the prior art, and the object thereof is to keep cracks in the arc tube pipe and the pipe closing cap while the encapsulated material such as lithium remains encapsulated in the arc tube pipe without being evaporated. It is an object of the present invention to provide a metal vapor discharge lamp that can hermetically seal the arc tube pipe.

[0009]

In order to achieve the above-mentioned object, a metal vapor discharge lamp according to the present invention comprises an arc tube made of single crystal alumina whose both ends are open, and an arc tube formed in a convex column shape. It has a small diameter hole penetrating on the central axis of the convex column whose diameter is smaller than the inner diameter of the pipe, and the projection formed on the small diameter of the convex column is directed to the outside, and the bottom part is fitted to both ends of the arc tube pipe. Pipe closing cap made of aluminized alumina, a small diameter hole closing cap made of a conductive cermet, which is fitted into a projecting portion of a small diameter hole formed in the pipe closing cap, and a pipe closing cap of the small diameter hole closing cap. A halogen-resistant sealing material for hermetically sealing the inside of the arc tube pipe, provided in the gap between the fitting portion of the electrode core, and an electrode mandrel implanted inside the small-diameter hole closing cap; Closed small hole Characterized in that and an outer lead pin planted on the outside of the cap.

[0010]

In the metal vapor discharge lamp according to the present invention, as described above, the both ends of the arc tube pipe are closed by a convex column-shaped pipe closing cap fitted to the both ends and the pipe closing cap. A small-diameter hole closing cap fitted in the small-diameter hole and two closing bodies are used in two steps. Then, in the case of enclosing a filling material in the arc tube pipe, first, one end of the arc tube pipe is completely closed by the pipe closing cap and the small diameter hole closing cap. Then, the other end of the arc tube pipe is closed only by the pipe closing cap, and the small diameter hole is closed by the small diameter hole closing cap after the inclusion is put into the arc tube pipe through the small diameter hole formed in the pipe closing cap. ..

In closing the small diameter hole formed in the pipe closing cap in the final closing step of the closing with the small diameter hole closing cap, the small diameter hole closing cap is fitted with the pipe closing cap because the closing portion has a small diameter. The amount of the sealing material for filling the gap between the parts and hermetically sealing the arc tube pipe is reduced. Therefore, a small amount of heat is required to melt the sealing material, and the sealing material is melted and solidified in a short time. Further, the radiant heat generated when the glass frit is heated is blocked by the pipe closing cap and is difficult to be conducted to the arc tube pipe. Therefore, evaporation of the inclusions in the arc tube pipe and cracking of the arc tube pipe are prevented. It can be prevented. Further, since the small-diameter hole closing cap that closes the small-diameter hole also becomes small, the occurrence of cracks in the small-diameter hole closing cap can be prevented.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a metal vapor discharge lamp according to an embodiment of the present invention. In addition, in FIG.
Reference numeral 100 is added to the portion corresponding to and the description is omitted. A discharge lamp 110 shown in the figure is an arc tube pipe 112 made of a cylindrical single crystal alumina whose both ends are open.
And the protruding portion having the convex column shape is the arc tube pipe 1.
Pipe closing caps 114a and 114b made of translucent alumina having a small diameter hole penetrating on the central axis of the convex column, and a conductive cermet formed to have substantially the same diameter as the small diameter hole. And small-diameter hole closing caps 130a and 130b.

Then, the pipe closing cap 114
A and 114b have convex column-shaped projections facing outward, and bottom surfaces thereof are sealed at both end openings of the arc tube pipe 112 with a glass frit 122a serving as a halogen-resistant sealing material. In addition, the small-diameter hole closing cap 130
"a" is sealed by a glass frit 122b in a projection opening of a small diameter hole formed in the pipe closing cap 114a. On the other hand, the small-diameter hole closing cap 130b
Is integrally fired and fixed to the projection opening of the small diameter hole formed in the pipe closing cap 114b together with the pipe closing cap 114b.

Further, the small-diameter hole closing cap 130a,
An electrode mandrel 118 having a coil 116 wound around the tip is implanted inside each of the 130b, and an external lead rod 120 is implanted outside the electrodes. The conductive cermet that constitutes the small-diameter hole closing cap 130 is made of alumina and tungsten. The above is the schematic configuration of the metal vapor discharge lamp according to the present embodiment,
Next, a method of forming the metal vapor discharge lamp and a specific operation will be described.

First, when molding the discharge lamp 110 shown in FIG. 1, as shown in FIG. 2, an opening at one end of the discharge lamp 110 is formed by a pipe closing cap 114b integrally formed with the small diameter hole closing cap 130b. Glass frit 12
It is completely closed by 2a, and the opening at the other end is closed by the glass frit 122a only with the pipe closing cap 114a. Then, the pipe closing cap 114a
After inserting an enclosure containing lithium or the like into the arc tube pipe 112 from the small-diameter hole formed in the pipe, the pipe closing cap 11
The small diameter hole 4a is sealed by the glass frit 122b with the small diameter hole closing cap 130a.
Completely seal.

FIG. 3 shows the pipe closing cap 114.
The explanatory view of the final sealing step of hermetically sealing the small diameter hole of a by the small diameter hole closing cap 130a through the glass frit 122b is shown. As shown in the figure, the vacuum container 1
The discharge lamp 110 is installed on the support table 134 provided in the unit 32 with the pipe closing cap 114b on the lower side. Then, the molded body of the ring-shaped glass frit 122b is sandwiched between the protrusion openings of the small diameter holes formed in the pipe closing cap 114a, and the small diameter hole closing cap 130a is fitted.

Further, the small diameter hole closing cap 130a.
And the tantalum heater 136 arranged so as to be close to the periphery of the fitting portion of the pipe closing cap 114a and the projection opening of the pipe closing cap 114a.
Is ignited by a high-frequency coil 138 provided outside the vacuum container 132. Then, the radiant heat of the tantalum heater 138 melts the molded body of the glass frit 122b, and the melted glass frit 122b permeates the entire gap of the fitting portion as shown in FIG. The incandescence is stopped, the glass frit 122b is cooled and solidified, and the arc tube pipe 112 is completely sealed.

Here, the pipe closing cap 114a
Since the protruding portion is formed with a small diameter, the tantalum heater 138 arranged close to the periphery of the protruding portion is also downsized. Further, since the molded product of the ring-shaped glass frit 122b sandwiched between the projecting portion opening of the small diameter hole, the small diameter hole closing cap 130a and the fitting portion is small, it is necessary to melt the molded product of the glass frit 122b. The radiant heat from the small tantalum heater 136 is small, and the glass frit 122b is melted and solidified in a short time. Radiant heat from the tantalum heater 136 is blocked by the convex columnar bottom surface of the pipe closing cap 114a that seals the opening of the arc tube pipe 112, and is difficult to conduct to the arc tube pipe 112. 1
The temperature of the enclosed material in 12 does not rise.

As described above, the discharge lamp 11 according to the present embodiment.
No. 0 does not raise the temperature of the enclosed material in the arc tube pipe 112, and the glass frit 122b is melted and solidified in a short time so that the arc tube pipe 112 can be sealed quickly. It is possible to prevent the inclusions from evaporating. Even if the tantalum heater 136 is made incandescent as described above, the radiant heat is still generated.
Since it is hard to conduct to 12, the crack does not occur in the arc tube pipe 112 made of single crystal alumina. Further, the small-diameter hole closing cap 130a for closing the small-diameter hole of the pipe closing cap 114a can be small even if the diameter of the arc tube 112 is large.
It is also possible to prevent the generation of cracks due to thermal shock when the incandescent of 36.

[0020]

As described above, according to the metal vapor discharge lamp of the present invention, the opening portions at both ends of the arc tube pipe are closed by the pipe closing caps having the small diameter holes having the convex column shape, and the pipes are closed. The projecting portion port of the small diameter hole formed in the cap is closed by the small diameter hole closing cap.
Therefore, even if the arc tube has a large diameter, the closing surface of the pipe closing cap and the small diameter hole closing cap has a small diameter, and therefore the sealing material provided for sealing the closing surface is also small, The sealing material is melted and solidified in a short time, and the arc tube pipe is quickly sealed. Further, radiant heat due to heating in melting the sealing material is blocked by the bottom surface of the convex column-shaped pipe closing cap, and it is difficult to conduct to the arc tube pipe, so that cracking of the arc tube pipe is prevented and the arc tube is prevented. It is also possible to prevent the temperature rise of the filling material in the pipe and to seal the arc tube pipe without evaporating the filling material.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a schematic configuration of a metal vapor discharge lamp according to an embodiment of the present invention.

2 is an explanatory view of a state before sealing the arc tube pipe shown in FIG. 1. FIG.

FIG. 3 is an explanatory view of a final sealing step of the arc tube pipe shown in FIG.

FIG. 4 is an explanatory diagram of a schematic configuration of a conventional metal vapor discharge lamp.

[Explanation of symbols]

 10, 110 ... Discharge lamp 12, 112 ... Arc tube pipe 14, 114 ... Pipe closing cap 18, 118 ... Electrode mandrel 20, 120 ... External lead rod 22, 122 ... Glass frit 130 ... Small diameter hole closing cap 132 ... Vacuum container 134 ... Support stand 136 ... Tantalum heater 138 ... High-frequency coil

Claims (1)

[Claims] 1. An arc tube pipe made of single crystal alumina having both ends opened, and a small diameter hole formed in a convex column shape and penetrating on a central axis of the convex column having a diameter smaller than the inner diameter of the arc tube pipe. A pipe closing cap made of alumina whose bottom portion is fitted to both end openings of the arc tube pipe, and a small diameter hole formed in the pipe closing cap. Airtightly seals the inside of the arc tube pipe provided in the gap between the small-diameter hole closing cap made of a conductive cermet fitted in the mouth of the protrusion and the pipe closing cap of the small-diameter hole closing cap. A halogen-resistant sealing material, an electrode mandrel implanted inside the small diameter hole closing cap, and an external lead rod implanted outside the small diameter hole closing cap. Characterizing Genus vapor discharge lamp.