JPH05234572A - Tubular bulb - Google Patents

Abstract

PURPOSE:To melt the specified filling material at the time of high temperature to maintain the air-tightness, and prevent the oxidation of a lead-in foil and an outer conductor by filling a clearance part, which is generated in the periphery of the outer conductor inside of a pinch seal part of an end of a glass bulb, with the specified filling material. CONSTITUTION:A fine clearance 8 is generated in the periphery of an outer conductor 7, which is sealed inside of a seal part 2, by a difference of thermal expansion rate between the outer conductor 7 and a bulb in a sealing process. As the filling material 9, the powder glass, which is mainly composed of the compound of boric acid and phosphorus oxide and to which the oxide of antimony and bismuth and silicon or the like is added at need, is blended. The binder, which is obtained by mixing nitrocellulose at about 1% to isoamyl acetate, is mixed in the powder glass to form the slurry, and the slurry is dropped to a lead-out point of the clearance 8, and the inside of the clearance 8 is filled with the slurry by the capillarity, and after drying it, the filling material is heated at about 300 deg.C. When the temperature of the filling material 9 exceeds a melting point thereof during the use, the clearance 8 is filled with the filling material 9 to maintain a lead-in foil 3 and a conductor 7 air-tight and prevent the oxidation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention does not oxidize the introduction foil by intrusion of outside air from a minute void portion generated in the outer peripheral portion of the outer conductor of the introduction conductor buried by pinching the end portion of the glass bulb. This is about the tube.

[0002]

2. Description of the Related Art Conventionally, halogen bulbs used for illumination and infrared rays are pinched at both ends of a straight tube type quartz glass bulb, and molybdenum introduction foils are embedded in both sealing portions. The inner conductor connected to these introduction foils is introduced into the bulb and the tungsten filament is mounted between them, and the outer conductor connected to the other end of the introduction foil, such as a molybdenum wire, is sealed. Out of the department,
The bulb is filled with a required halogen together with an inert gas such as argon.

[0003]

In order to manufacture such a halogen light bulb, first, an inner conductor and an outer conductor are welded to both ends of an introduction foil to form an introduction conductor, and then two introduction conductors are formed. Tungsten filament is connected between each inner conductor to form a mount, and then the lead conductor mounted with this filament extends into the quartz glass bulb,
Both ends of the quartz glass bulb are heated and pinched to form a sealing portion, and the introducing foil is embedded in the sealing portion. At this time, the extremely thin introduction foil is air-tightly adhered to the sealing portion, but since the outer conductor having a large diameter has a higher thermal expansion coefficient than quartz glass, the outer conductor of the pinch portion of the outer conductor is cooled in the cooling process after the pinch. The one shrinks more greatly, and a minute void is generated between the two. Then, the bulb is evacuated and filled with an inert gas and halogen to complete the bulb.

When such a halogen light bulb is lit, the temperature of the sealing portion becomes high, and the sealing body is gradually oxidized by the air existing by penetrating into the void formed in the outer peripheral portion of the outer conductor of the sealing portion, and finally, the sealing body is finally oxidized. The airtightness is lost and the bulb goes out.

Oxidation of the introducing foil due to the invasion of air as described above always occurs as long as the introducing conductor having the introducing foil and the non-sealing outer conductor is used.

The present invention provides a bulb which is free from the risk of oxidation of the introducing foil due to the entry of air.

[0007]

In the bulb of the present invention, an end portion of a glass bulb accommodating a light emitting member is pinch-sealed, and an introduction conductor is embedded and sealed in the pinched sealing portion. The introduction conductor is an introduction foil sealed to the sealing portion,
And an inner conductor and an outer conductor which are respectively connected to the introduction foil, and filled with a filler mainly containing a compound of boric acid and phosphorus oxide in the void portion generated in the outer peripheral portion of the outer conductor existing in the sealing portion. Is.

[0008]

With this structure, when the temperature of the sealing portion becomes equal to or higher than the melting point of the filler, the filler is melted to fill the void in the outer peripheral portion of the outer conductor and keep the introduction foil and the outer conductor airtight. Oxidation of the foil and the outer conductor can be prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a halogen bulb which is an embodiment of the present invention. In FIG. 1, both ends of a straight tube type bulb 1 made of transparent quartz glass are pinch-sealed to form a sealing portion 2, and a molybdenum introducing foil 3 is embedded in both sealing portions. An internal conductor 4 made of a refractory metal wire such as tungsten introduced into the bulb 1 is connected to the introduction foils 3. A tungsten filament 5, which is a light emitting member, is stretched between these internal conductors 4. This filament 5 is supported by an anchor 6.
Furthermore, the outer conductor 7 is connected to the introduction foil 3 and the sealing portion 2
From the outside. In the outer peripheral portion of the outer conductor 7 existing in the sealing portion 2, a minute void 8 formed due to a difference in coefficient of thermal expansion from the valve 1 is generated. Filler is filled in the void 8. The bulb 1 is filled with a required halogen together with an inert gas such as argon.

In the present invention, the introduction foil 3 and the inner conductor 4 and the outer conductor 7 connected to both ends of the introduction foil 3 are collectively referred to as an introduction conductor.

In the sealing step, the gap 8 is formed by the valve 1
Since the thermal expansion coefficient of molybdenum forming the outer conductor 7 is larger than that of the silica glass in the process of gradually cooling the silica glass in the softened state when the introduction conductor is arranged and pinch-sealed. , The outer conductor 7 rather than the sealing portion 2
Shrink more greatly, and this difference becomes the void 8. The void 8 formed in this manner extends along the outer conductor 7 in the unit of one tenth of a millimeter, and communicates with the outside world.

The filler 9 is mainly composed of a compound of boric acid and phosphorus oxide, and if necessary, an oxide of antimony, bismuth, silicon or the like is added as an additive. In order to obtain such a filler, a required distribution of boric acid and phosphorus oxide, and an additive are mixed and heated to prepare a glassy solid, which is then crushed into powder glass. This powdered glass and a binder obtained by mixing about 1% of nitrocellulose with isoamyl acetate are mixed to form a slurry.
Then, this slurry is dripped at the lead-out point of the outer conductor 7 from the sealing portion 2. Then, the slurry infiltrates and fills the voids 8 due to the capillary phenomenon. Then, after drying at about 100 ° C., it is heated at a temperature of about 300 ° C. to expel the nitrocellulose. In this way, the filler 9 is formed.

When this halogen bulb is lit, its operating heat is transmitted to the sealing portion 2 and the filled filling material 9 is heated. When the temperature exceeds the melting point of the filler 9, the filler 9 is in a molten state and fills the voids 8 in the outer peripheral portion of the outer conductor 7 to keep the introduction foil 3 and the outer conductor 7 airtight, It has a function of preventing the outer conductor 7 from being oxidized.

According to an experiment, a halogen bulb having a life of 2000 hours having the structure of the above embodiment was subjected to a comparative test in an atmosphere having a sealing temperature of 380 ° C., and the melting point of the filler was 300 to 350 ° C. No oxidation was observed on the surface of all the molybdenum-introduced foils in the tube of the present invention having 2000 hours. On the other hand, in the conventional tube without the filler, under the same conditions, the molybdenum-introduced foil was oxidized and lost the airtightness only after 500 to 900 hours had passed, and all the wires were broken. From this result, the effect of the present invention is clear.

Further, when a comparative test was conducted in an atmosphere having a sealing portion temperature of 450 ° C., one having 1/10 of the total amount of the fillers containing the above-mentioned filler was oxidized on the surface of the molybdenum-introduced foil. Admitted. In addition, some of the seals had cracks. On the other hand, the tube of the embodiment of the present invention having the melting point of the filler of 350 to 400 ° C. is 20
When 00 hours had passed, no oxidation was observed on the surface of all the molybdenum-introduced foils. Under the same conditions, the conventional products without fillers had the molybdenum-introduced foils oxidized and lost airtightness only after 200 to 500 hours had elapsed, and all the wires were broken. From this result, it can be said that when the sealing portion temperature reaches 450 ° C., it is better to use a filler having a high melting point.

[0017]

As described above, in the bulb of the present invention, the end of the glass bulb containing the light emitting member is pinched and sealed,
An introduction conductor is embedded in the sealed sealing portion, and the introduction conductor is composed of an introduction foil hermetically sealed in the sealing portion, and an inner conductor and an outer conductor respectively connected to the introduction foil. When the temperature of the sealing part exceeds the melting point of the filling material by filling the voids generated in the outer peripheral portion of the outer conductor, which are mainly composed of a compound of boric acid and phosphorus oxide, the filling material melts. As a result, the voids in the outer peripheral portion of the outer conductor can be filled and the introduction foil and the outer conductor can be kept airtight, so that a short life due to oxidation of the introduction foil and the outer conductor can be prevented.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part of a tube which is an embodiment of the present invention.

FIG. 2 is a partially cutaway front view of the tube.

[Explanation of symbols]

 1 Valve 2 Sealing Part 3 Introduction Foil 4 Inner Conductor 5 Filament 7 Outer Conductor 8 Void 9 Filler

Claims (1)

[Claims] 1. A bulb in which an end portion of a glass bulb containing a light emitting member is pinch-sealed, and an introducing conductor is embedded and sealed in the pinched sealing portion, wherein the introducing conductor is sealed in the sealing portion. The introduction foil, and a filling mainly composed of a compound of boric acid and phosphorus oxide, which is composed of an inner conductor and an outer conductor respectively connected to the introduction foil, and which is generated in the outer peripheral portion of the outer conductor existing in the sealing portion. A tube characterized by being filled with a material.