JPH0418198Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to light bulbs used in the photochemical industry, semiconductor device manufacturing field, lighting field, and other fields, particularly for large current light bulbs. The present invention relates to a light bulb characterized by its hermetically sealed structure.

[Technology background]

For example, in the photochemical industry and the semiconductor device manufacturing field, light bulbs that efficiently emit ultraviolet rays, such as mercury lamps, are widely used.

In such fields, high-intensity ultraviolet rays are often required, so mercury lamps with a large current capacity are generally used.

For example, in high-pressure mercury lamps or ultra-high-pressure mercury lamps for large currents, the amount of mercury that is the main component of the luminescent gas is large, and the gas pressure inside the luminous tube at the time of lighting is approximately 30% when the rated power consumption is 2000W. The atmospheric pressure is very high, and the amount of heat generated is large. Therefore, especially the glass of the hermetically sealed part is required to have high heat resistance. It is necessary that the mercury in the arc tube completely evaporate during lighting, and therefore it is necessary that there be no low temperature areas where mercury condenses within the arc tube during lighting.

For this reason, conventional high-pressure mercury lamps or ultra-high-pressure mercury lamps do not use the so-called rod seal structure, in which the glass that forms the light bulb's arc tube is directly welded to the power supply lead rod for an airtight seal. A so-called foil seal structure using a worn metal foil is adopted.

Figure 2 shows an example of an ultra-high pressure mercury lamp constructed using a foil seal structure. In the figure, 1 is a glass arc tube, 2A, 2B is a glass cylinder with a bottom, 3A, 3B is a band-shaped metal foil, 4A, 4
B is an internal lead rod, 5A, 5B are external lead rods,
6A and 6B are electrodes, and 7A and 7B are glass cylinders for holding internal lead rods.

The arc tube 1 consists of a tube section 11 for surrounding the light emitting section that bulges out at the center, and sealed tube sections 12A and 12B that continue to both ends of the tube section 11. Inside these sealed tube sections 12A and 12B, bottomed cylindrical bodies 2A and 2B are formed. The open ends thereof are respectively arranged toward the outer ends of the sealed tube parts 12A and 12B, and the external lead rods 5A and 5B are connected to the bottomed cylinder body 2A, respectively.
and the inner lead rod 4 is inserted into the cylindrical hole of 2B.
A and 4B are bottomed cylinders 2A and 2B, respectively.
These internal lead rods 4A and 4 are arranged to extend into the light emitting space surrounding portion 11 from the end surface of the bottom wall of the
Electrodes 6A and 6B are fixed to the tips of B, respectively, and internal lead rod holding cylinders 7A and 7B are located outside the bottom walls of the bottomed cylinders 2A and 2B inside the sealed tube parts 12A and 12B, respectively. ,
The internal lead rods 4A and 4B are inserted into the respective internal lead rods 4A and 4B.
The metal foils 3A and 3B are arranged on the outer periphery of the bottomed cylinders 2A and 2B so as to extend in the axial direction of the cylinders, and one end is electrically connected to the internal lead rods 4A and 4B, respectively, and the other end is connected to the internal lead rods 4A and 4B, respectively. It is electrically connected to external lead rods 5A and 5B. The outer peripheries of the bottomed cylinders 2A and 2B are sealed with metal foils 3A and 3B, respectively, to the tube portion 1.
It is hermetically welded to the inner circumferences of 2A and 12B.

On the proximal end side of the internal lead rods 4A and 4B, the portions of the glass of the sealed tube portions 12A and 12B facing the internal lead rod holding cylinders 7A and 7B are heated and then pressed. By applying negative pressure inside the sealed tube portions 12A and 12B, the outer peripheral surfaces of the internal lead rod holding cylinders 7A and 7B and the sealed tube portion 12A are
and the inner circumferential surfaces of 12B are welded, thereby forming narrowed portions 8A and 8B. Sealed tube part 1
At the outer ends of 2A and 12B, the glass at the outer ends is heated and melted, whereby the metal foil 3
The exposed parts of A and 3B are covered with glass.

[Problem to be solved by the invention] However, while the ultra-high pressure mercury lamp is lit, the pressure inside the arc tube 1 becomes considerably high.For example, if the rated power consumption is 2000W and the rated current is 60A, The pressure inside the arc tube 1 becomes as high as, for example, about 30 atmospheres.

However, in the ultra-high-pressure mercury lamp configured as described above, cracks tend to occur early in the welds between the internal lead rod holding cylinders 7A and 7B and the sealed tube parts 12A and 12B, and therefore, in the worst case, There is a problem in that the arc tube 1 may burst, resulting in an extremely dangerous accident.

The inventor of the present invention conducted intensive research into the causes of such problems and found that a ring-shaped gap with a large radius was formed on the inner end side of the welded portion between the internal lead rod holding cylinders 7A and 7B and the sealing tube portions 12A and 12B. 9A and 9B are formed, and these gaps 9A and 9B cause the sealed pipe portions 12A and 12 to
It was discovered that cracks tend to occur early in glass B, and the present invention was completed.

[Purpose of invention]

The present invention was developed based on the above-mentioned circumstances, and its purpose is to prevent early cracking at the welded part between the sealing pipe part and the internal lead rod holding cylinder, and to prevent the occurrence of early cracks in the welded part between the sealed pipe part and the internal lead rod holding cylinder, and to The purpose of the present invention is to provide a light bulb that can be safely lit and used for a long period of time.

[Means for solving problems]

The light bulb of the present invention includes a glass arc tube consisting of a light emitting part surrounding tube section and a sealed tube section following this, and an open end inside the sealed tube section of this arc tube that is connected to the outer end of the sealed tube section. A bottomed cylinder made of glass arranged to face the side, an external lead rod inserted into the cylindrical hole of the bottomed cylinder, and an end face of the bottom wall of the bottomed cylinder into the light emitting space surrounding part. an internal lead rod arranged to extend; an electrode or filament provided at the tip of the internal lead rod; and an internal lead rod located outside the bottom wall of the bottomed cylinder inside the sealed tube section a cylinder for holding the internal lead rod made of glass that holds the internal lead rod in a state in which the internal lead rod is inserted therein; and a band-shaped metal foil whose other end is electrically connected to the external lead rod, and the outer circumferential surface of the end of the inner lead rod holding cylinder on the side surrounding the light emitting space is It is characterized by a tapered shape.

[Effect]

According to this configuration, in a state where the outer periphery of the internal lead rod holding cylinder and the inner periphery of the sealing tube part are welded, a ring-shaped gap is formed at the end of the welded part on the side of the light emitting space surrounding part. Even so, since the outer circumferential surface of the end of the inner lead rod holding cylinder on the side surrounding the light emitting space is tapered, the radius of the ring-shaped gap is small and the area of the gap is small. Therefore, while the bulb is lit, the pressure inside the arc tube is quite high, but the total pressure applied to the ring-shaped gap is small, and as a result, the weld between the internal lead rod holding cylinder and the sealing tube part is prematurely bonded. The light bulb can be safely lit and used for a long period of time without causing any cracks.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings regarding the construction of an ultra-high pressure mercury lamp employing a foil seal structure.

FIG. 1 is an explanatory sectional view showing one embodiment of the present invention, in which 1 is an arc tube made of, for example, quartz glass, and 2A and 2B are cylindrical bottomed cylinders made of, for example, quartz glass. , 3A, 3B are strip-shaped metal foils made of molybdenum, 4A, 4B are internal lead rods made of tungsten, 5A, 5B are external lead rods made of tungsten, 6A, 6B are electrodes, 7A, 7B are quartz, etc. It is a cylindrical body made of glass for holding the internal lead rod.

The arc tube 1 consists of a large diameter bulging central tube section 11 for surrounding the light emitting section and small diameter sealed tube sections 12A and 12B continuing at both ends thereof.

The internal lead rod holding cylinders 7A and 7B each have an outer peripheral surface 71A at the end on the side of the light emitting space surrounding section 11.
and 71B are tapered, that is, the diameters of the outer peripheral surfaces 71A and 71B of the end portions have slopes that gradually become smaller toward the light emitting space surrounding portion 11 side.

Each of the bottomed cylinders 2A and 2B is a sealed tube part 1.
Inside the tubes 2A and 12B, the open ends thereof are arranged toward the outer ends of the sealed tube portions 12A and 12B.

One end of the external lead rods 5A and 5B is inserted into the cylindrical holes of the bottomed cylinders 2A and 2B, respectively, and the internal lead rods 4A and 4B are inserted into the light emitting space surrounding portion from the bottom wall end surfaces of the bottomed cylinders 2A and 2B, respectively. Each of the internal lead rods 4A and 4B has an electrode 6 at its tip.
A and 6B are fixed.

The internal lead rod holding cylinders 7A and 7B are located outside the bottom walls of the bottomed cylinders 2A and 2B inside the sealed tube portions 12A and 12B, respectively, and the internal lead rods 4A and 4B are inserted into their respective interiors. In this state, the base ends of the internal lead rods 4A and 4B are held.

Metal foils 3A and 3B are each bottomed cylinder 2A
and 2B so as to extend in the cylindrical axis direction, one end side is bent and electrically connected to the inner lead rods 4A and 4B, respectively, and the other end side is bent and electrically connected to the outer lead rods 5A and 5B. It is connected to the.

The outer peripheries of the bottomed cylinders 2A and 2B are hermetically welded to the inner peripheries of the sealed tube portions 12A and 12B via metal foils 3A and 3B, respectively. This welding can be performed, for example, by heat-treating the sealed tube portions 12A and 12B from the outside.

On the proximal end side of the internal lead rods 4A and 4B, the portions of the glass of the sealed tube portions 12A and 12B facing the internal lead rod holding cylinders 7A and 7B are heated and then pressed. By applying negative pressure inside the sealed tube sections 12A and 12B, the entire outer circumferential surfaces of the internal lead rod holding cylinders 7A and 7B and the inner circumferential surfaces of the sealed tube sections 12A and 12B are welded together. Thus, narrowed portions 8A and 8B are formed.

At the outer ends of the sealed tube sections 12A and 12B, the exposed portions of the metal foils 3A and 3B are covered with glass by heating and melting the glass at the outer ends.

According to the above embodiment, in a state where the outer periphery of the internal lead rod holding cylinders 7A and 7B and the inner periphery of the sealing tube parts 12A and 12B are welded, the end of the welded part on the light emitting space surrounding part 11 side Even if ring-shaped gaps 9A and 9B are formed in the inner lead rod holding cylinders 7A and 7B, the outer circumferential surfaces 71A and 71B of the end portions on the side of the light emitting space surrounding portion 11 are tapered, so that The radius of the ring-shaped gaps 9A and 9B is small, and the opening area of the gaps 9A and 9B is small. Therefore, while the ultra-high pressure mercury lamp is lit, although the pressure inside the arc tube 1 is quite high, for example, about 30 atmospheres, the total pressure applied to the ring-shaped gaps 9A and 9B is small, and as a result, the internal lead rod is held. Cylindrical bodies 7A and 7B and sealed pipe parts 12A and 12B
The ultra-high pressure mercury lamp can be safely lit and used for a long time without causing early cracks in the welded part with the lamp.

[Experiment example]

A specific experimental example will be described below.

Γ Rated power consumption: 2000W (voltage: approx. 33V, current: approx. 60A) Γ Pressure inside the arc tube (when lit at rated power consumption):
30 atm Γ Thickness of the sealed tube part of the arc tube: 3 to 4 mm Γ Outer diameter of the sealed tube part of the arc tube: 25 mm Γ Inner diameter of the cylindrical body for holding the internal lead rod: 6 mm Γ Center of the cylindrical body for holding the internal lead rod Part outer diameter: 14
mm Γ Diameter of the outer surface of the end of the internal lead rod holding cylinder:
7 mm Γ Length of the slope formed on the outer peripheral surface of the end of the cylinder for holding the internal lead rod: 5 mm Based on the examples described above, 100 ultra-high pressure mercury lamps according to the present invention under the above conditions were manufactured, and these 30% of the rated power consumption for each ultra-high pressure mercury lamp
When we conducted an experiment in which the lamps were actually lit for 1,000 hours continuously at an increased power consumption of 2,600 W, cracks occurred at the weld between the internal lead rod holding cylinder and the sealing tube in all ultra-high pressure mercury lamps. There were no accidents and the lights could be safely turned on until the end.

On the other hand, 100 ultra-high-pressure mercury lamps were manufactured for comparison in the same manner as above, except that a cylinder with a uniform shape and the same outer diameter was used as the cylinder for holding the internal lead rod. When we conducted a similar experiment to actually light up 100 ultra-high pressure mercury lamps, 13 of them burst due to cracks forming at the weld between the internal lead rod holding cylinder and the sealing tube. An accident occurred, and there was a problem in terms of safety.

Although one embodiment of the present invention has been described above, various modifications can be made to the present invention. That is, (1) the internal lead rod holding cylinder may have a cross-sectional profile other than a circle when cut at right angles to the cylinder axis, for example, a quadrilateral, a polygon of pentagon or more, an ellipse, etc.

(2) Instead of using the electrodes 6A and 6B, a so-called incandescent light bulb type structure may be used in which a coiled filament is connected between the internal lead rods 3A and 3B.

Furthermore, the present invention is not limited to the above embodiments, and includes light bulbs used in the photochemical industry field, semiconductor device manufacturing field, lighting field, and other fields, such as ultra-high pressure mercury lamps, high-pressure mercury lamps, ultra-high pressure xenon discharge lamps, and high-pressure xenon lamps. It can be applied to discharge lamps, incandescent lamps, etc.

[Effect of idea]

As explained above, according to the present invention, when the outer periphery of the internal lead rod holding cylinder and the inner periphery of the sealing tube part are welded, a ring is attached to the end of the welded part on the light emitting space surrounding part side. Even if a ring-shaped gap is formed, because the outer peripheral surface of the end of the internal lead rod holding cylinder on the side surrounding the light emitting space is tapered, the radius of the ring-shaped gap is small and the opening area of the gap is small. becomes small, and therefore, while the bulb is lit, the pressure inside the arc tube is quite high, but the total pressure applied to the ring-shaped gap is small, and as a result, the pressure between the inner lead rod holding cylinder and the sealing tube section is small. Cracks do not occur early in the welded portion, and the light bulb can be safely lit and used for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is an explanatory sectional view showing an embodiment of the light bulb of the present invention, and FIG. 2 is an explanatory sectional view showing an example of a conventional light bulb. 1... Luminous tube, 11... Luminous space surrounding part, 12
A, 12B... Sealed tube part, 2A, 2B... Bottomed cylinder, 3A, 3B... Metal foil, 4A, 4B... Internal lead rod, 5A, 5B... External lead rod, 6A,
6B... Electrode, 7A, 7B... Cylindrical body for holding internal lead rod, 8A, 8B... Constricted portion, 9A, 9B...
ring-shaped gap.

Claims (1)

[Claims for Utility Model Registration] A glass arc tube consisting of a light emitting part surrounding tube section and a sealed tube section following this, and an open end inside the sealed tube section of this arc tube. A bottomed cylinder made of glass arranged to face the outer end, an external lead rod inserted into a cylindrical hole of the bottomed cylinder, and a bottom wall end face of the bottomed cylinder surrounding the light emitting space. an internal lead rod arranged to extend into the inner lead rod; an electrode or filament provided at the tip of the inner lead rod; a cylinder for holding an internal lead rod made of glass that holds the internal lead rod with the lead rod inserted therein; and an internal lead rod holding cylinder made of glass that extends in the axial direction of the cylinder on the outer periphery of the bottomed cylinder, one end of which is connected to the internal lead. a band-shaped metal foil that is electrically connected to the rod and whose other end is electrically connected to the external lead rod; A light bulb characterized by a tapered surface.