JPH0197366A - Short arc discharge lamp - Google Patents

Abstract

PURPOSE:To perform sealing excellent in airtightness even when positional slippage between separator glass and a metal foil is generated by making width of the metal foil laid on the flat surface of a separator glass smaller than width of the flat surface of the separator glass. CONSTITUTION:A quartz glass container 1, in which xenon gas is sealed, consists of the main body 2 in the oval-spherical shape and the sealing parts 3 and 4 extending to its both sides. A tungsten-made cathode 5 having a diameter of about 2mm and a tungsten-made anode 6 having a larger diameter of about 5mm than this, whose respective base end parts are sealed to the sealing parts 3 and 4, are connected to the outer leading-in bodies 11 and 12 through the molybdenum-made metal foils 9 and 10 for air-tight sealing laid on the surfaces of the separator glass 7 and 8. Here, by making width l of the metal foil laid on the flat part of the separator glass smaller than width L of the flat surface of the separator glass, lowering of air-tightness is checked in spite of possible positional slippage between the separator glass and the metal foil.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention] (Industrial Field of Application) - The present invention relates to a short arc discharge lamp that has a large current and is lit in the open, and particularly to improvements in its sealing part.

(Prior art) In general, short arc discharge lamps such as xenon lamps and ultra-high pressure mercury lamps are different from high pressure discharge lamps for general lighting.
It is used for various purposes as a compact light source consisting only of an arc tube without an outer tube.

For example, in the case of a xenon lamp, the electrode sealing structure is a stem type that uses a stem for a class of about 1y or more, and a foil sealing that uses a sealing metal foil made of a high-melting point metal such as molybdenum for a class of 500W or less. Typed. However, in the case of the stem type 2, it is difficult to seal the electrode made of tungsten and the quartz glass container, which has a different coefficient of thermal expansion, so a graded tube (stepped glass tube) with a gradually different coefficient of thermal expansion is used for sealing. I'll do it though.

Graded tubes have a lower melting point and strain point than quartz, and the need to lower the temperature requires a considerably longer sealing section, which forces the lamp to be larger.

By the way, in recent years, there has been a strong demand for downsizing of projection devices, etc. in line with the downsizing of lighting circuits, and the above-mentioned lamps used as light sources for these devices have also been changed from stem types to foil-sealed types in order to downsize. It has become necessary to move on.

On the other hand, ultra-high pressure mercury lamps and xenon mercury lamps containing xenon and mercury have higher lamp voltage than xenon lamps even at the same wattage, so it is possible to lower the lamp current; Even with a large wattage, it is easy to use a foil-sealed type.

In addition, in the case of lamps that are lit with direct current, such as xenon lamps, the anode consumes a large amount of power, and
Since the lamp voltage is lower than other lamps, it requires a large current, so it is designed to be large.

That is, the anode of a 350 W class xenon lamp is formed flat so that the base end of the electrode, that is, the part sealed to the sealing part of the quartz glass container, especially the tip side, is thinner. This is because by reducing the thickness of the sealing part of the anode, the strength of the sealing part is improved and its reliability is increased.

Further, the proximal end side of the anode is connected to the external introducing body through a metal foil hermetically sealed to the sealing portion, but since the current is large, a plurality of metal foils are used. These metal foils are attached to each flat surface of a separator glass formed into a flat shape that matches the flat part of the anode, one end of the metal foil is attached to the flat part of the anode, and the other end is attached to the external introduction body. connected to. FIG. 3 shows a configuration explanatory diagram of an anode mount sealed to the sealing part of the quartz glass container, (6) is an anode with a flat sealing part (6a), (8) is a separator glass, 00 ．． α0 is the metal foil attached to each of the flat surfaces (8a) and (8a) of the separator glass (8),
θ2 is the external introduction body. The above metal foil QO), (1
01 is about 20~30μ1 wide in the center! is formed to have the same width as the separator glass (8), and one end is connected to the flat part (6a) of the anode and the other end is welded to the external introducing body θ, and if necessary, the above metal When using foil, the welded part (10) is bent and doubled to increase welding strength.

An anode mount having such a configuration is placed at the open end of a quartz glass container (not shown), and after the end of the container is heated and melted, it is compressed toward the center to form a sealing part.
Anode mount metal foil aO).

The OO is hermetically sealed to the sealing part.

However, some leaks were observed in the sealing portion of the lamp formed in this manner.

As a result of a detailed study by the present inventors regarding the cause of this, it was found that in the sealing process of the quartz glass container, metal foil 0 (2)
, (10) and the separator glass (8) are shifted as shown in FIG. 4, and the metal foil 00 protrudes from the flat surfaces (8a), (8a) of the separator glass (8).

Particularly thin edge part (10a) of 00 is bent.

It was found that the molten silica glass did not flow sufficiently into the bent portion during the formation of the sealing portion, resulting in so-called cavities, which caused leakage.

(Problem to be solved by the invention) Conventional short arc discharge lamps as mentioned above.

Some leaks occurred from the sealing part.

SUMMARY OF THE INVENTION Therefore, the present invention aims to eliminate the above-mentioned conventional drawbacks, and aims to provide a long-life short arc discharge lamp that does not cause leakage in the sealing portion.

[Structure of the invention]

(Means for Solving the Problems) In the short arc discharge lamp of the present invention, the width l of the metal foil attached to the flat surface of the separator glass made of quartz glass is preferably smaller than the width of the flat surface of the separator glass. is 1
．． 1 < L/ 0 < 1.5.

(Function) According to the above configuration, even if a shift occurs in the positional relationship between the separator glass and the metal foil during the process of sealing the open end of the quartz glass container, the metal foil will not protrude from the separator glass. Therefore, it is possible to prevent the formation of cavities in the sealing portion that occur in the protruding portions of the metal foil, and it is possible to form a sealing portion with excellent airtightness.

[Embodiments of the invention]

The present invention will be described in detail below with reference to an embodiment shown in two drawings. Fig. 1 shows a 350W class xenon lamp which is an embodiment of the present invention, and (1) shows a lamp with a lighting time of 10 hours.
It is a quartz glass container filled with xenon gas, which also has atmospheric pressure, and consists of an ellipsoidal main body (2) surrounding a discharge space and sealing parts (3) and (4) extending on both sides of the main body (2). (5) is a tungsten cathode with a diameter of approximately 2.0 mw.

(6) is a tungsten anode with a diameter of about 5.0 mm, which is much larger than the cathode (5), and has two electrodes (5), each of which has its base end connected to the sealing part (3), (4), and is connected to the external introducing body αυ (1) through the molybdenum airtight sealing metal foil (9) attached to the surface of the separator glass (8) and αQ. ing.

Furthermore, FIG. 2 shows the structure of the electrode (anode side) mount, which is the essential part of the present invention. A flat part (6a) with a width of 5 mm is formed on the distal end side of the base end of the anode (6), and a separate glass (8) made of quartz glass, which is also formed in a flat shape, is arranged adjacent to this. Ru. The drawing planes (8a) and (8a) of the separate glass (8) each have a thickness of 20~
Approximately 30μ metal foils α@ and kilns are attached, and each of these metal foils (1 (1, (width of II = 5 tnx, formed smaller than the width L of the separate glass flat surface (8a) 61RIL) is attached. is used, and if necessary, both ends of the metal foil cLI are bent to make it double in order to increase the welding strength.
One end is welded to the anode (6), and the other end is welded to the external introduction body α2 to form an electrode mount.

This electrode mount is placed at the open end of the quartz glass container (1) at the portion to be sealed and whose inner diameter is designed to match the maximum outer diameter of the sealed portion of the electrode mount,
After heating and melting the open end, the fused silica glass is compressed toward the electrode mount, and the fused silica glass is fused to the metal foil αI (11) and the separate glass (8) to form an airtight sealing part (4).
) is formed.

In such a sealing process, the lamp of the present invention can be used.

Since the metal foil (11, width α) is formed smaller than the width of the separate glass (8), there may be a slight deviation in the positional relationship between the two.

The edge portion (10a) of the metal foil will not protrude from the flat surface (8a) of the separate glass and will not bend, thus preventing the formation of cavities within the sealing portion (4) as seen in the past. An airtight sealing part (4) can be obtained.

Next, using the same 350W class xenon lamp as in the above example,
The width of the flat part of the anode is 5 mm, the width of the metal foil is 15 mm, and
The table below shows the results of using a leak tester to determine the occurrence of leaks in the sealed portion when the width of the separate glass was varied.

All surface leaks are caused by cavities along the edges due to deformation of the edges of the metal foil, which are also the parts protruding from the separate glass. From the results shown in the table, the width of the separate glass should have an allowance of at least 10% relative to the width l of the metal foil. In other words, L/l
> 1.1 is found to be effective in preventing leaks.

However, if there is too much margin in the width of the separate glass so that L/l≧1.5, the inner diameter of the open end of the quartz glass container, which is the part to be sealed, will be correspondingly increased. must, therefore.

Not only does the sealing process take longer.

Since the time the electrode is in contact with impure gas becomes longer, this is not preferable from the viewpoint of cost and quality.

Further, the same tests as above were conducted for metal foils having different widths, and it was found that similar results could be obtained if "<L/l<1.5".

In the above embodiments, a xenon lamp with a large anode that is lit with direct current was described, but in a xenon lamp that is lit with alternating current, the anode and cathode are of the same shape.

Even if it is not as large as the above DC lighting lamp, when using a lamp with larger picture electrodes than other lamps, the sealing section at both ends should have the same configuration as the sealing section on the anode side of the above embodiment. Moreover, the present invention can be effectively applied not only to xenon lamps but also to other short arc discharge lamps such as ultra-high pressure mercury lamps that use large electrodes.

〔Effect of the invention〕

As described above, according to the configuration of the present invention, it is possible to prevent leakage caused by the edges of the sealing metal foil attached to the flat surface of the separate glass, and to obtain a long-life short arc discharge lamp. .

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a xenon lamp which is an embodiment of the present invention, Fig. 2 is an explanatory view of the anode mount of the lamp, and Fig. 3
The figure is an explanatory diagram of a conventional anode mount of a xenon lamp, and FIG. 4 is a diagram showing the state of the conventional anode mount after a sealing process. (1)...Quartz glass container. (3) , <4)...Sealing part, (5)...
···cathode. (6)・・・Anode, (8)・・・
...Separator glass. (8a)...Flat surface of separator glass. (IQI...metal foil, circle...external introduction body. (1)...width of metal foil. (L)...width of separator glass flat surface Figure 4 10a

Claims (2)

[Claims] (1) A pair of electrodes are each connected to the external introducing body through a metal foil hermetically sealed to the sealing part of a quartz glass container, and the metal foil is attached to the flat surface of a quartz glass separator glass. A short arc discharge lamp characterized in that the width of the metal foil is set smaller than the width of the flat surface of the separator glass. (2) When the width of the metal foil is l (mm) and the width of the flat surface of the separator glass is L (mm), 1.1<L/l<1.
5 Claim No. 1 characterized in that
Short arc discharge lamps as described in section.