JPH06140000A - Low pressure electric discharge lamp and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a lamp of long life by welding glass bars each other, after heated and softened, form a bead mount by interposing lead wires from both sides, sealing this bead mount in a glass bulb, and sealing electric discharge gas inside this bulb, so as to prevent a rise of starting voltage and early blackening. CONSTITUTION:Only a pair of glass bars 1a, 1b are heated by a gas burner flame 4a, and melted and softened surface of both glass bars 1a, 1b are pressed to each other and welded, to interpose lead wires 2, 2 therebetween. Accordingly, since the lead wires 2, 2 are not heated perticularly but preheated from both glass bars, a temperature of the lead wire does not rises high to prevent generation of oxidation. Thus by a little oxidizing the lead wire, in the case of lighting as a fluorescent lamp, and electron can be efficiently captured by the lead wires 2, 2 actuated as an anode. Accordingly, no overload is applied to a side of a filament coil 6, and heating is prevented to suppress early vaporization of an electric radioactive substance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low pressure discharge lamp such as a fluorescent lamp using a bead mount and a method for manufacturing the low pressure discharge lamp.

[0002]

2. Description of the Related Art A low-pressure discharge lamp such as a fluorescent lamp is constructed such that a glass bulb having a phosphor film formed on its inner surface is provided with a hot cathode consisting of a filament coil in which a tungsten wire is wound in a double or triple manner. , The coil is coated with an electron emissive material (emitter). In addition, a discharge gas such as argon gas for facilitating the discharge and an appropriate amount of mercury are enclosed in this bulb.

These fluorescent lamps and the like use a mount in which a filament coil is connected between two lead wires in order to support the hot cathode composed of the filament coil. Most of these mounts use flare stems or button stems, but recently glass bulbs such as compact lamps have a smaller diameter (outer diameter 25 mm or less).
Because of what has been done and the need for resource saving and cost reduction, bead mounts with a small number of parts and a simple structure have begun to be adopted.

This bead mount is easy to manufacture by simply fixing two lead wires with a glass bead. For example, in the manufacture, two lead wires are inserted into a sliced glass tube, and the glass tube is heated and melted from the outer periphery to be contracted to fix the two lead wires as a lump of glass, or juxtaposed. The heated and softened glass rod is pressed against the two lead wires and the lead wire is forcibly embedded in the glass rod (on the contrary, the placed glass rod is heated and softened, and the lead wire is pressed against it to force the glass There is a method of embedding in the rod).

[0005]

A problem to be solved by the present invention is that a lamp using a bead mount manufactured by the above method often has a short life.

As a result of various studies on the occurrence of this short life, the present inventor has found that the cause is excessive oxidation of the lead wire. That is, in the manufacturing method as described above, the lead wire cannot be embedded in the glass gob unless the glass forming the bead is in a softened or melted high temperature state, and in the former case, it was sliced. The lead wire inserted in the glass tube is also heated by the burner that heats and melts the glass tube, and the temperature becomes considerably high. Further, in the latter case, the glass gob is expected to be in a considerably high temperature state, and the traces of the lead wires pushed into the glass gob must be compensated for, so that additional heating may be required.

After all, in the bead mount thus manufactured, not only the glass bead but also the lead wire is directly heated, or the surface of the lead wire in the vicinity of the bead is excessively heated due to the heat transfer from the glass bead having a considerably high temperature. May oxidize. Oxidation of the lead wire begins to be recognized when the lead wire is in the atmosphere of about 400 ° C. or higher.

In addition to the mechanical role of supporting the filament coil in these mounts, the lead wire also serves as an anode in AC lighting and plays an electrical role of capturing electrons.

By the way, when the lead wire is oxidized, the electron trapping ability is reduced depending on the degree of oxidation, and thus the number of electrons jumping to the filament coil side increases. Then, the filament coil side is overheated and the temperature of the coil rises, which accelerates the evaporation of the electron emissive material (emitter) applied to this coil, and the electron emissive material (emitter) is consumed early to shorten the lamp life. I found out.

It is an object of the present invention to provide a long-life discharge lamp using a bead mount with little or no oxidation of the surface of the lead wire, and a method for manufacturing the lamp.

[0011]

The low-pressure discharge lamp according to claim 1 of the present invention comprises a mount in which two lead wires supporting electrodes are fixed by glass beads, and the mount is sealed to the end of the bulb. In the low-pressure discharge lamp, the glass beads of the mount are characterized in that the lead wire is sandwiched and fixed by a pair of glass rods.

According to a second aspect of the present invention, there is provided a method of manufacturing a low pressure discharge lamp, wherein a pair of glass rods are arranged on both sides of two lead wires arranged substantially in parallel with each other so as to face the lead wires with a space therebetween. A step of heating and softening the rod and then sandwiching the lead wire from both sides to form a bead mount by welding them to each other; and a step of placing the bead mount in the end portion of the glass bulb and sealing the both. And a step of enclosing a discharge gas in the glass bulb.

[0013]

[Function] Since the surface of the internal lead wire of the mount is clean,
When the lamp is lit, this lead wire also captures a desired amount of electrons and operates at a normal temperature without excessive electrons jumping into the filament coil that forms the hot cathode. The lamp life can be extended without evaporation and scattering.

Further, in manufacturing the bead mount, the lead wire is not directly heated in order to reduce the thermal influence, so that the generation of oxidation can be prevented.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the manufacturing process of a bead mount in sequence, in which 1a and 1b are glass rods made of a pair of lead glass,
Reference numerals 2 and 2 are lead wires made of iron, nickel alloy wire, Dumet wire, or the like, and 3 is a support insertion hole 3 of the lead wires 2 and 2.
It is a mount holder having a and 3a. Further, 4 is a gas burner, 4a and 4a are gas burner flames 4a and 4a.

First, one side surface of a pair of glass rods 1a and 1b supported by a holder (not shown) as shown in FIG. 3A is heated by gas burner flames 4a and 4a. Next,
(B) As shown in the figure, the support insertion hole 3a of the mount holder 3,
The lead wires 2 supported by 3a are directed toward predetermined positions on both sides of the lead wire 2a, and the heated surfaces of the pair of glass rods 1a and 1b are faced to each other and approached. Then, the glass rods 1a and 1b are pressed so as to sandwich the lead wires 2 and 2 from both sides.
By this pressing, the softened or melted side surfaces of the glass rods 1a and 1b come into contact with each other, and the lead wire is provided between the glass beads 1 in which both the glass rods 1a and 1b are integrated as shown in FIG. A bead stem 5a having 2 and 2 interposed is completed. The lead wires 2 and 2 of the bead stem 5a are bent into a predetermined shape, and a filament coil 6 formed by double or triple winding a tungsten wire serving as a hot cathode is connected between the ends of the lead wires 2 and 2. Then, the bead mount 5 as shown in FIG.

An electron emissive material mainly containing (Ba, Ca, Sr) O is applied and filled in the turn of the filament coil 6 of the bead mount 5.

Next, as shown in FIGS. 2 (a) and 2 (b), the bead mount 5 and the exhaust pipe 9 are arranged in the open end of the bulb 7 having the phosphor film 8 formed on the inner surface thereof. The opening end portion is heated and melted to be closed, and the crush seal portion 10 is formed.
And lead wires 2 and 2 of the bead mount 5
Then, the exhaust pipe 9 is hermetically sealed to obtain the lamp shown in FIG. After that, the bead mount 5 is sealed at the other opening end of the bulb 7, and the inside of the bulb 7 is exhausted through the exhaust pipe 9 to discharge gas (here, discharge gas is a gas such as argon or krypton, (Including mercury, which is liquid or alloyed and vaporized after it is put into the bulb) is enclosed to complete the fluorescent lamp.

According to the method for manufacturing the bead mount as described above, only the pair of glass rods 1a and 1b are heated by the gas burner flames 4a and 4a.
The melted and softened surfaces of 1b are pressed against each other and welded together (in FIGS. 2 (b) and 2 (c), the glass beads 1 have respective glass rods 1a, 1b having different cross sections), and the lead wires 2, 2 are interposed therebetween. The lead wires 2 and 2 are not particularly heated because they are interposed, so that the glass rods 1a and 1
Since only the heat is applied from b, the temperature does not rise so much and the generation of oxidation is prevented.

There is little or no oxidation in the lead wires 2 and 2, and the lead wires 2 and 2 acting as an anode can efficiently capture electrons when they are lit as a fluorescent lamp. it can. Therefore, since the lead wires 2 and 2 efficiently capture electrons, an overload is not applied to the filament coil 6 side, overheating is prevented, and the electron emissive material (emitter) is not vaporized early. It was possible to obtain a long-life lamp. Further, since the lead wire 2 is less oxidized, the generation of impure gas in the valve is less, and the shortening of the life such as the increase of the starting voltage and the prevention of premature blackening can be prevented. The present invention is not limited to the above embodiment. For example, the lamp is not limited to a fluorescent lamp, and may be another low-pressure discharge lamp such as an ultraviolet radiation lamp using an electrode having an electron emitting substance as a hot cathode. The hot cathode may also have a double or triple coil and a core wire. It may be a stick coil inserted. Further, it may be a low-pressure discharge lamp in which mercury such as argon, krypton, xenon, neon, or nitrogen is not enclosed in the bulb.

The shape of the lamp of the present invention is a straight tube shape or a U shape.
It may be a curved tube shape such as a letter shape, a W shape, or a saddle shape. Further, the material of the lead wire and the glass bead is not limited to that of the embodiment, and the lead wire made of a material that does not easily oxidize, the lead wire in which the internal, sealed, and external members are changed, and the generation of an impure gas with a low melting point Materials having similar thermal expansion coefficients to each other may be selected in consideration of the material of the bulb as well as the small number of glass beads.

Further, the means for forming the bead mount sealing portion is not limited to the crushing sealing using the pincher of the embodiment, and other means such as shrink sealing of glass by heating or exhaust without using an exhaust pipe. The sealing may be performed simultaneously with the sealing.

Further, the holding means and the heating means of the glass rod forming the glass beads are not limited to those in the embodiment. Furthermore, although the above-described manufacturing method can largely prevent the oxidation of the lead wire, in the present invention, the glass bead molding is performed in a non-oxidizing gas atmosphere such as nitrogen, argon or a mixed gas of nitrogen and hydrogen. Regardless of the direction, addition of such means makes it possible to completely prevent oxidation of the lead wire.

[0024]

As described in detail above, according to the present invention, there is little or no oxidation in the lead wire, and when it is operated as a low-pressure discharge lamp, the lead wire serving as the anode efficiently emits electrons. Since it can be captured and the filament coil side is not overheated and the electron emitting substance (emitter) is not vaporized at an early stage, a long-life lamp can be obtained. Further, since the lead wire 2 is less oxidized, the generation of impure gas in the valve is less, and the shortening of the life such as the increase of the starting voltage and the prevention of premature blackening can be prevented.

Also, the bead mount can be easily manufactured, and can be provided with high productivity and at low cost.

[Brief description of drawings]

1 (a) to 1 (d) are perspective views sequentially showing a manufacturing process of a bead mount of a discharge lamp of the present invention.

2 (a) to 2 (c) show a sealing process of a discharge lamp of the present invention, FIG. 2 (a) is a sectional front view, and FIG. 2 (b) is a drawing (a).
Is a side view, and FIG. 6C is a cross-sectional side view after crushing and sealing the valve.

[Explanation of symbols]

 1: Glass beads 1a, 1b: Glass rod 2: Lead wire 5: Bead mount 6: Filament coil (hot cathode) 7: Bulb 10: Sealing part

Claims (2)

[Claims] 1. A low-pressure discharge lamp comprising a mount, in which two lead wires supporting electrodes are fixed by glass beads, sealed at the end of a bulb, wherein the glass beads of the mount have a pair of glass rods. A low-pressure discharge lamp that is sandwiched between and fixed by welding. 2. A pair of glass rods are arranged on both sides of two lead wires arranged substantially in parallel so as to be spaced apart and opposed to the lead wires, and these glass rods are heated and softened, and then sandwiched from both sides of the lead wire. The method comprises the steps of welding the scissors to each other to form a bead mount, arranging the bead mount inside the end of the glass bulb to seal the two together, and enclosing a discharge gas in the glass bulb. A method of manufacturing a low-pressure discharge lamp, characterized in that