JPH05258722A - Tubular bulb - Google Patents

Abstract

(57) [Abstract] [Purpose] The joint area between the metal foil and the inner conductor or the outer conductor, which is sealed in the seal portion, is spot-welded and the contact area is small, so the capacity of the joint is insufficient. The purpose is to solve these problems, such as heat generation, fusing caused by this, and destruction of the sealed part due to thermal stress strain. [Structure] A glass bulb 7 is sealed with a metal foil 2 to which an introducing conductor 4 (5) is joined, and the joined portion is a strip-shaped reinforcing member 9 formed of a metal foil so as to cover the introducing conductor 4 (5). Are connected to each other across the introduction conductor 4 (5) and the metal foil 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an introducing member, such as a metal halide lamp, a high pressure metal vapor discharge lamp, a halogen bulb, etc., which is sealed in a bulb mainly made of quartz as a material of a glass bulb.

[0002]

2. Description of the Related Art A bulb such as a high-pressure metal vapor discharge lamp or a halogen bulb using quartz glass for an arc tube has a thermal expansion coefficient close to that of the quartz glass in order to maintain the airtightness of the sealing portion. A metal foil such as molybdenum foil is used as a sealing member for supplying a predetermined current to the filament.

A bulb generally used as a light source for illumination of roads, stadiums, baseball fields, parks, shops, etc., for example, a light emitting tube A of a metal halide lamp has a structure as shown in FIGS. 3 and 4. That is, the introduction member 1 of this arc tube A
Are spot-welded and fixed to the inner end side of the metal foil 2 such as molybdenum by using the round rod-shaped electrode shaft 4 around which the electrode coil 3 is wound as an inner conductor and the outer conductor wire 5 as an outer conductor on the outer side. I am doing it. Then, the introduction member 1 is placed in a sealing tube at both ends of a quartz glass bulb 7 having a substantially elliptical outer shape, and the sealing tube is heated with oxyhydrogen gas from the outside and is made of quartz glass. Is melted and the roots of the metal foil 2 and the electrode shaft 4 and the external conductor 5 in the vicinity of the metal foil 2 are buried with the fused quartz glass to form the sealing portion 6 and hermetically seal the introduction member 1. There is.

Next, the exhaust pipe 8 provided in the central portion of the valve 7 is attached to an exhaust device (not shown), and the valve 7 and the electrode coil 3 are exhausted while exhausting the inside of the valve 7 through the exhaust pipe 8.
Is degassed, and then a predetermined amount of a mixture of mercury and ScI, NaI, DyBr3, TmBr3,
HaBr such as a mixture of HoBr3 and Ar, K
The arc tube A is completed by enclosing a starting gas such as r or Xe and sealing the exhaust pipe 8.

By the way, in this type of metal halide lamp, the electrode shaft 4 as the inner conductor around which the coil 3 is wound is in the shape of a round bar, so that several points of welding with the metal foil 2 are joining points, and the welding device therefor is also used. There are variations in the bonding strength due to adjustments, etc. These are not particularly problematic in a low-power lamp with a relatively small current, for example, an output of several hundred watts or less, but a high output of a large current, for example, several kilowatts or more, used for lighting in a stadium, a baseball field, a park, etc. Problems can occur in the lamp. Although the joint between the metal foil 2 and the electrode shaft 4 is embedded in the glass sealing portion, there is a difference in the coefficient of thermal expansion between the electrode shaft 4 and the glass of the bulb 7 due to the difference in the coefficient of thermal expansion between the electrode shaft 4 and the glass. In addition, the high output lamp has a large electrode coil and a heavy weight, and a large force is applied to the joint between the electrode shaft 4 and the metal foil 2 to peel the joint, and this point joint has a high resistance when energized. There were cases where heat was generated, and due to this, there were problems such as fusing of the joint and cracks at the sealing part due to thermal stress strain.

As a means for solving these problems, for example, the tip of the electrode shaft 4 is machined into a flat surface. It is conceivable to join the metal foil 2 to both surfaces of the electrode shaft 4, but the former means that ultra-hard metal such as tungsten is extremely difficult to process such as cutting and crushing, and also takes time.
The latter method requires a quartz plate between both metal foils 2 and complicates the assembly, etc., and the cost is high.

[0007]

The problem to be solved is that the contact area of the joint between the metal foil and the inner conductor or the outer conductor is small, so that heat generation due to insufficient capacity of the joint and fusing caused by this There is damage to the sealed part due to heat stress strain, etc., and it is extremely difficult to work to solve these problems.
At the same time, the cost is increased.

[0008]

[Means for Solving the Problems] In a glass bulb in which a metal foil having an introduction conductor joined thereto is sealed, a strip-shaped reinforcing member formed of the metal foil so as to cover the introduction conductor is provided at the joined portion. It is characterized by being joined across the foil.

[0009]

[Operation] Since the contact area of the joint between the metal foil and the inner conductor or the outer conductor can be increased, the electric resistance at this joint does not become high, and heat generation and fusing of the joint, and excessive strain at the seal are generated. It is possible to prevent cracks and the like due to.

[0010]

1 and 2 show an embodiment of the present invention, in which the same parts as those in FIGS. 3 and 4 are designated by the same reference numerals and the description thereof is omitted. The introduction member 1 of the arc tube A uses a molybdenum foil 2 having a width of about 6 mm, a length of about 100 mm and a thickness of about 25 microns as the metal foil 2, and the molybdenum foil 2 has a round bar-shaped inner conductor on the inner side thereof. Wire diameter is about 1.8 mm
The electrode shaft 4 made of tungsten containing thorium is joined by spot welding (electrical resistance welding). Also,
An electrode coil 3 made of a tungsten wire having a wire diameter of about 0.8 mm is wound around the electrode shaft 4. The outer conductor of the molybdenum foil 2 has a wire diameter of about 2.0 m as an outer conductor.
The external conducting wires 5 made of molybdenum rods of m are connected and fixed by spot welding (electrical resistance welding). In the present invention, a width of about 6 mm from above the joint of the electrode shaft 4 (and the external conductor 5) joined to the molybdenum foil 2,
A strip-shaped reinforcing member 9 (9) of molybdenum foil having a length of about 3 mm and a thickness of about 25 microns is covered so as to straddle the two, and the reinforcing member 9 (9) is covered with the electrode shaft 4 (and the external conductor 5) and molybdenum. The foil 2 is fixed by spot welding (electrical resistance welding) at several points. The maximum inner diameter is about 3
The introducing member 1 is arranged in a sealing tube having an inner diameter of about 8 mm, which is joined to both ends of a quartz glass bulb 7 having an outer shape of 6 mm and a maximum inner length of about 50 mm and having a substantially elliptical outer shape. Sealing is performed by melting the sealing tube made of quartz glass by heating with oxyhydrogen gas from the outside and burying the metal foil 2 and the electrode shaft 4 in the vicinity of the metal foil 2 and the root of the external conductor 5 with the fused quartz glass. The part 6 is formed and the introduction member 1 is hermetically sealed. Then, the normal exhaust treatment work is carried out below, and the exhaust pipe 7
From mercury 100mg and DyBr3, TmBr3, HoB
20 mg of the halogenated mixture of r3 and 100 Torr of Ar gas are enclosed, and the exhaust pipe 8 is fusion-sealed to complete the arc tube A.

1 KW (rated lamp current of about 10 A) is used by using the introducing member 1 of the structure of the present invention in which the joining portion between the molybdenum foil 2 and the introducing conductors 4 and 5 is covered with the strip-shaped reinforcing member 9 made of molybdenum foil. And 2 kW (Rated lamp current approx. 20
We produced 20 metal halide lamps of A), and increased these lamps by 20% of the rated output 1.2KW and 2.4K.
Flashing was performed by repeatedly turning on the light for 2 hours and turning off the light for 30 minutes. Then, at the time of lighting, the temperature of the outer wall of the sealing portion 6 where the joint portion of the electrode shaft 4 is located and the temperature of the outer wall of the sealing portion 6 closer to the outer end portion side by 20 mm from the joint portion are respectively measured by using PR thermocouples. In addition to the measurement, a visual inspection was performed to determine whether or not the fused portion was fused and the sealed portion 6 was cracked. As a result,
In both output lamps, the outer wall of the sealing portion 6 where the joint portion of the electrode shaft 4 is located and the outer wall of the sealing portion 6 separated by 20 mm from the outer end portion have substantially the same temperature, and the joint portion is overheated. Not,
In addition, there was no fusing of the molybdenum foil 2 or the like, and no cracking of the glass bulb 7.

The present invention is not limited to the above-described embodiments, but can be applied without departing from the scope of the present invention. For example, the glass material is not limited to quartz glass and may be hard glass such as high silicate glass, and the shape thereof may be a straight tube type or a bulb closed at one end. Further, the metal foil for sealing and reinforcing is not limited to molybdenum foil, and other metal such as tantalum foil may be used. In short, the metal foil can be appropriately selected and applied in the tube using the metal foil as the sealing member.

In the above embodiment, the case where both the joints of the inner and outer conductors joined to the metal foil are reinforced has been described. However, the invention is not limited to the embodiment, and the outer conductor side at the end also radiates heat, so at least the reinforcement is required. It may be applied to the inner conductor side, which is close to the electrode coil and directly receives conduction heat and radiant heat and has a high temperature.

Further, the bulb is not limited to a metal halide lamp, but may be another lamp such as a mercury lamp or other high-pressure discharge lamp or a halogen bulb, and the sealing portion is formed by crushing and sealing using a molding die. May be.

[0015]

As described above, according to the present invention, since the introduction conductor joined to the metal foil is covered and the band-shaped reinforcement is joined by welding, the joint area between the metal foil and the introduction conductor is increased and the The contact resistance can be reduced and the joint strength can be improved. There is no overheating at the joint, and it is possible to prevent melting of the metal foil caused by this overheating and cracking of the glass bulb due to thermal stress strain. Further, the present invention is particularly effective for a high-power lamp having a heavy electrode or mount and a lamp using a double coil electrode filled with a large amount of electron emitting material.
It is possible to provide a tube that is easy to work and has a simple structure and has a long life.

[Brief description of drawings]

FIG. 1 is a front view of a discharge lamp showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the introduction member taken along the line AA in FIG.

FIG. 3 is a front view of a discharge lamp showing a conventional example.

FIG. 4 is an enlarged cross-sectional view of the introduction member taken along line BB in FIG.

[Explanation of symbols]

 1 Introduction Member 2 Metal Foil (Molybdenum Foil) 3 Electrode Coil 4 Inner Conductor (Electrode Shaft) 5 External Conductor (External Conductor) 6 Sealing Part (Sealing Tube) 7 Glass Bulb 9 Strip Reinforcement

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

Claims (1)

[Claims] 1. A glass bulb in which a metal foil having an introduction conductor joined thereto is sealed, and a strip-shaped reinforcing member formed of the metal foil so as to cover the introduction conductor at the joined portion straddles and joins the introduction conductor and the metal foil. A tube that is characterized by being.