JPH0652834A - Tubular bulb - Google Patents

Abstract

PURPOSE:To provide a tubular bulb which has no fear of foil separation or leakage by using such a lead-in structure that a separator glass is laid between metal foils for the tubular bulb. CONSTITUTION:Such a lead-in structure 1 that a separator glass 5 is laid between sealing metal foils 4A, 4B each of which has one end welded to an inside conductor 2 with a light emitting filament or a discharge electrode and the other end welded to an outside conductor 3 is sealed to the end of a silica glass bulb 6. A tubular bulb is formed by welding three or more metal foils 4A, 4B folded together at time welding portion 41 between the sealing metal foils 4A, 4B and the inside conductor 2. In this way, much thermal stress is applied to the vicinity of the welding portion 1-3mm apart from a welding point, and so the metal foils in this area are elongated during lighting to show high electric resistance and temperature rise but reinforce themselves in electric, chemical errosion resistant and temperature property because the multilayered metal foils in the vicinity of the welding point. The metal foils in this area is thus prevented from fusion without runout and a long-life tubular bulb which has no fear of leakage is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high pressure discharge lamp, a halogen bulb, and the like, and more particularly to a structure of an introduction body of a bulb sealing portion having a large current.

[0002]

2. Description of the Related Art Short arc metal halide lamps,
High-pressure discharge lamps such as ultra-high-pressure mercury lamps and xenon lamps, or halogen bulbs that use quartz glass for bulbs are used for various purposes as compact light sources consisting only of arc tubes without an outer tube. .

In order to maintain the airtightness of these tubes with quartz glass, a metal foil made of molybdenum foil or the like is used as an introduction body in the sealing portion. Usually, this molybdenum foil has a thickness of 20 to 30 μm, and if it is thicker than this, the quartz glass bulb may crack due to the thermal expansion coefficient or the airtightness cannot be maintained. Not only foil breaks occur during sealing work and lighting, but there are also current limitations.

Therefore, with this kind of lamp, 10 ampere, 2
For 0 amp and high current type lamps, a plurality of metal foils for sealing are used in parallel. As shown in FIG. 4, the introduction body 1 of, for example, a short arc metal halide lamp that uses a plurality of metal foils, for example, two metal foils, has a structure of an inner conductor 2 and an outer conductor 3 made of a refractory metal such as tungsten. Molybdenum foil 4 is used as metal foil on the flat portions 21 and 31 formed by cutting and forming both upper and lower surfaces.
A and 4B are welded together with molybdenum foil 4
A separator glass 5 made of rectangular flat quartz glass is interposed between A and 4B and between the end faces of the inner conductor 2 and the outer conductor 3. 41, ... are welding points,
42, ... Show the vicinity of the welded portion.

The introduction body 1 having such a structure is arranged in the opening end of the quartz glass bulb 6 shown in FIG. 3, and if the end of the bulb 6 is heated and melted to form the sealing portion 61, The molybdenum foils 4A and 4B are hermetically sealed in the sealing portion 61.

However, the above-mentioned lamp including the introduction body 1 expands and contracts when the lamp blinks. The expansion and contraction due to this blinking may be about the same as that of the quartz glass bulb 6 and the introduction body 1. However, since the thermal expansion coefficient of quartz glass is smaller than that of molybdenum or tungsten, the expansion and contraction stress thereof is a metal member such as molybdenum or tungsten. Take to the side. When the lamp is lit, this stress causes the thin and weakest molybdenum foils 4A and 4B to melt and the lamp becomes defective.

Further, the quartz glass bulb 6 hermetically seals the molybdenum foils 4A and 4B in a central portion without a gap, but at the welded portions of the molybdenum foils 4A and 4B and the internal conductor 2, the quartz glass bulbs 6A and 4B and the inside are sealed. If the conductor 2 is completely fused with the quartz glass, cracks may occur in the quartz glass due to the difference in coefficient of thermal expansion when the lamp is turned on. Therefore, the conductor 2 is not completely hermetically sealed. On the contrary, if a perfect gap is formed between the inner conductor 2 and the quartz glass (actually, a slight gap is formed by heating during the sealing work and then cooling), this time A metal halide or the like sealed in the bulb 6 as a luminescent substance enters this gap and reacts with the molybdenum foils 4A and 4B in this portion to corrode and weaken the molybdenum foils 4A and 4B to lower the strength and facilitate cutting. Will end up.

Then, the molybdenum foil 4A as described above,
The place where 4B is cut off occurs in the vicinity of the welded portion 42 which is about 1 to 3 mm away from the welding point 41 with the internal conductor 2 where the temperature rises most and the expansion difference is large due to the large amount of discharge heat applied to the electrode when it is turned on. There is a case that foil breakage is promoted because the vicinity 42 of the portion is eroded by the halide and the electric resistance is high.

[0009]

The problem to be solved is that the cutting of the metal foil that occurs in the vicinity of the welded portion between the internal conductor and the metal foil cannot be prevented.

The present invention has been made in view of the above circumstances, and in a tube using an introduction body in which a separator glass is interposed between a plurality of metal foils, there is no fear of foil breakage or leakage. The purpose is to provide a ball.

[0011]

According to a first aspect of the present invention, in a tube according to the present invention, a separator glass is interposed between a plurality of sealing metal foils, and one end of the metal foil emits a light emitting filament or discharge. In a tube obtained by sealing an inner conductor having an electrode and an outer conductor welded to the other end to the end of a quartz glass bulb, the welded portion between the sealing metal foil and the inner conductor has 3 The feature is that more than one metal foil is polymerized and welded.

The tube according to claim 2 of the present invention is characterized in that the metal foil to be polymerized is formed by folding back an end portion of the sealing metal foil.

[0013]

[Function] Since the metal foil is further polymerized and welded in the vicinity of the connection portion between the inner conductor and the metal foil, the connection portion is reinforced and the fixing strength can be improved, and at the same time, the connection portion is corroded by the halide or the like and weakened. Can be prevented.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an introduction body 1 according to the present invention, and FIG. 3 shows a short arc metal halide lamp. The same parts as those in FIG. 4 described above are designated by the same reference numerals and the description thereof will be omitted.

Molybdenum foils 4A and 4B are welded as metal foils to the flat portions 21 and 31 formed by cutting and forming the upper and lower surfaces of the end portions of the inner conductor 2 and the outer conductor 3 which are electrode rods made of a high melting point metal such as tungsten. In addition, a separator glass 5 made of rectangular flat quartz glass is interposed between the molybdenum foils 4A and 4B.

One end of each of the molybdenum foils 4A and 4B is
A certain length of the tip portion is folded back, and another reinforcing metal foil 4Z is put in the folded portion and is welded and connected to the inner conductor 2 at two welding points 41, ... As a triple layer.

Reference numeral 22 is an electrode coil wound around the inner conductor 2, 42, ... Are near the welded portion 1 to 3 mm away from the welding points 41, 41 toward the outer conductor 3, and 8 is an insulator such as ceramics. And a lead wire.

In assembling the introduction body 1 as described above, the inner conductor 2 and the separator glass 5 which are flattened at the upper and lower surfaces and have the same thickness and which are formed in advance are connected in series, and the upper and lower flat portions 21 of the inner conductor 2 are The above-mentioned molybdenum foils 4A and 4B having the tip portions of the triple layers are applied on 21 and welding electrodes 7 and 7 are applied to the upper and lower molybdenum foils 4A and 4B to energize and weld the three members. For example, this welding uses molybdenum foil 4A, 4B
The welding is performed at the upper two welding points 41, 41.

Next, the end portions of the outer conductor 3 are put into a space where the other ends of the molybdenum foils 4A and 4B face each other until they come into contact with the end faces of the separator glass 5, and the upper and lower molybdenum foils 4A and 4B are welded in the same manner as above. The three electrodes are welded by applying the electrodes 7 and 7 to each other to energize them. In addition, here also two welding points 41, 4
1 is connected.

The introduction body 1 assembled in this manner is disposed at both ends of a substantially oval valve 6 made of quartz glass, heat-sealed in the same manner as before, and the inside of the valve 6 is opened from an exhaust pipe (not shown). Exhaust, DyBr ₃ , HoBr
_{3, TmBr 3, CsI, ScI} 3, halides such as NaI, After filled with an inert gas, such as mercury and argon, to complete the lamp by heat sealing the exhaust pipe.

A lamp completed by using the introduction body 1 having such a structure has one of the fixing fulcrums at the welding point 41 and the other at the glass sealing portion, and in the vicinity of the welding portion 42 1 to 3 mm away from the welding point. Although the molybdenum foils 4A and 4B in this portion are stretched and have a high electric resistance and have the highest temperature at the time of lighting due to a large amount of thermal stress, in the present invention, the molybdenum foils 4Z are multilayered in the vicinity of the welding point 41 to improve the electrical resistance. Since it is reinforced against heat, chemical erosion, and temperature, the molybdenum foils 4A and 4B in this portion do not become thin and fusing can be prevented.

Further, since the central portion of the sealing portion for keeping the lamp airtight is only sealed with one thin molybdenum foil 4A, 4B as in the conventional case, the adhesion with the quartz glass is also good. There is no fear of leaks.

If the foil thickness is 20 to 30 μm, three or more metal foils (triple layers) are required for the metal foil for reinforcing the vicinity 42 of the welded portion. The metal foil reacts with the halide enclosed in the bulb and weakens, causing foil breakage. On the other hand, if the number is too large, such as 6 or more, the difference in the coefficient of thermal expansion from the glass causes cracks in the glass bulb and waste of materials, so about 3 to 5 is sufficient.

Next, a specific example will be described.

Specific Example 1 Lamp rating 2 Kw (lamp voltage 120 V, lamp current 20 A) Elliptical bulb Minor diameter part inner diameter 36 mm, long diameter part inner diameter 50 mm Discharge electrode distance 30 mm Lamp total length 394 mm Sealing part length (one side) 140 mm Encapsulation Material DyBr ₃ 3 mg, HoBr ₃ 3 mg TmBr ₃ 3 mg, CsI 10 mg Hgbr ₂ 5 mg, Hg 90 mg Ar 100 toll Metal foil (molybdenum foil) Thickness 26 μm, width 6 mm, length 125 mm Folding length 8 mm, number of layers 3 layers. (As shown in Fig. 2, about 4 mm of the folded length of 8 mm is on the inner conductor and about 4 mm is on the separator glass) (Conventional product) Thickness 26 μm, width 6 mm, length 125 mm Inner conductor (electrode rod) outer diameter 2mm, length 25mm, flat part thickness 1mm, length 5mm Separator Thug glass (quartz) Thickness 1 mm, width 6 mm, length 117 mm The present invention product (three layers of the welded portion of the molybdenum foil end (triple))
20 pieces of each of the above and conventional products (1 layer of molybdenum foil end) were manufactured, and a blinking test for 4000 hours (lighting 5.5 hours, extinguishing 0.5 hours) was performed. The molybdenum foil in the vicinity of the welded portion of the internal conductor was blown, but in the product of the present invention, there was no lamp in which the molybdenum foil was blown.

The present invention is not limited to the above embodiment. For example, the bulb is not limited to a metal halide lamp, but may be an ultra-high pressure mercury lamp, a xenon lamp, a halogen bulb, or the like, and the bulb shape is not limited to the substantially elliptical shape shown,
The lamp may have a spherical shape, a straight tube shape, a curved tube shape or the like, and needless to say, it is not limited to the both-ends-sealed type, but one having a plurality of sets of introduction bodies sealed at one end is also applicable. The method of sealing is not limited, such as molding in a mold or using a crushing mold.

In the above embodiment, molybdenum foil is used as the sealing and reinforcing metal foil, but metal foil made of other material such as tungsten may be used. In addition, the metal foil was formed by folding back the tip of the sealing metal foil and inserting the reinforcing metal foil into it, but this is not the only option, and the sealing metal foil is folded back twice and integrated into three layers. Also, the reinforcing metal foil folded back once on the sealing metal foil is prepared as three layers, or two separate reinforcing metal foils are prepared on the sealing metal foil and the welded portion is prepared. It may be welded to.
In addition, the number of welding points connecting these metal foils and the inner conductor is 2
Not limited to points.

The reinforcing metal foil may be provided only on at least the side connected to the internal conductor. This is indispensable because the inner conductor side is close to the discharge electrodes and filaments, the temperature rise is high and the thermal effect is large, and the corrosion by the substance enclosed in the bulb is dealt with, and the temperature rise on the outer conductor side is low. Is unnecessary.

Further, in the above embodiment, two metal foils for electricity are used.
Although the case of using three sheets has been described, it goes without saying that the present invention can be applied to the case of using three or more sheets depending on the current capacity and shape. Further, it is not limited to one metal foil to which one inner conductor and one outer conductor are connected, and a plurality of conductors may be connected to one metal foil depending on the current capacity or the like. Further, the outer conductor is not limited to the above-mentioned one, and a metal foil for energizing and sealing may be extended to the outside of the sealing portion of the valve.

Furthermore, in the above-mentioned embodiment, the inner conductor is sandwiched by two metal foils from above and below and welded at once, but it is not limited to welding these three at a time. For example, the inner conductor and the upper metal can be welded together. It does not matter even if the separator glass is placed after welding the foil and the lower metal foil is welded.

[0031]

As described above in detail, according to the present invention, a large amount of thermal stress is generated in the vicinity of the welded portion 1 to 3 mm away from the welding point, and the metal foil in this portion stretches and has a high electric resistance at the time of lighting. However, since the metal foil in the vicinity of this welding point is reinforced in terms of electrical resistance, chemical erosion resistance, and temperature, the metal foil in this part will not become thin and fusing can be prevented. it can. In addition, even if the blinking is repeated and the stress for expanding and contracting the metal foil is applied to the sealing metal foil, the metal foil is reinforced as a triple layer or more in the vicinity of the weld where the force is the weakest and the weakest. There is no occurrence. Further, as in the conventional case, only one thin metal foil is sealed in the sealing portion for keeping the lamp airtight, so that the adhesion with the quartz glass is good and there is no fear of leakage. Can provide a long life tube.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an introduction body of the present invention.

FIG. 2 is a front view showing a main part of the embodiment shown in FIG.

FIG. 3 is a partial sectional front view showing a short arc metal halide lamp.

FIG. 4 is a perspective view showing an example of a conventional introducing member.

[Explanation of symbols]

 1: Introducer 2: Inner conductor (electrode rod) 3: Outer conductor 4A, 4B: Metal foil (molybdenum foil) 5: Separator glass 6: Quartz glass bulb 21, 31: Flat portion 41: Welding point 42: Near welded portion 61: Sealing part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideki Ito 1-4-2 Mita, Minato-ku, Tokyo Toshiba Lighting & Technology Corporation

Claims (2)

[Claims] 1. An introduction body in which a separator glass is interposed between a plurality of sealing metal foils, and an inner conductor having a light emitting filament or a discharge electrode is welded to one end of the metal foil and an outer conductor is welded to the other end. In a bulb sealed at the end of a quartz glass bulb, three or more metal foils are polymerized and welded at a welded portion between the sealing metal foil and the internal conductor. A tube to play. 2. The tube according to claim 1, wherein the metal foil to be polymerized is formed by folding back an end portion of a metal foil for sealing.