JPH06290736A - Fluorescent lamp and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a fluorescent lamp and its manufacture, in which any abnormal discharge is prevented from its occurrence at the time of disconnection of a filament so as to prevent breakage of its bulb. CONSTITUTION:Tensile force strong enough to part both disconnected end parts from each other, for example, by 1.0mm or more in the case of the disconnection of the filament 4 is applied to a filament 4. Consequently, since both disconnected end parts are parted from each other in the case of disconnection of the filament occurrence of abnormal discharge between these disconnected end parts is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp and a method for manufacturing the same, in which the current supply is surely stopped when the filament is broken at the end of its life.

[0002]

2. Description of the Related Art Generally, a fluorescent lamp has a fluorescent coating formed on the inner surface of a glass bulb and filaments sealed at both ends of the bulb, and a predetermined amount of mercury and argon are contained in the bulb. It is configured by enclosing a rare gas such as. The filament is formed by molding a tungsten wire into a double coil or a triple coil, and the legs formed at both ends are clamped to lead wires, respectively, so that the filament is laid between the lead wires.

By the way, in such a fluorescent lamp, an excessive load is applied to the filament at the end of its life, when it is subjected to shock or vibration, when it is misused or when it is lit at a high voltage, and the filament is broken. And it may be a defect. When the filament is broken, the current-carrying circuit is cut off and no current flows. Therefore, this lamp cannot be used and can be replaced.

[0004]

However, in the conventional case, the broken ends may be very close to each other in spite of the broken filaments. As described above, the broken ends of the filaments may be close to each other. Is abnormally close to each other, sparks may be generated between these ends, and abnormal discharge may occur.

In such an abnormal discharge, since a current flows through the filament, the filament is abnormally overheated and the lead wire made of nickel or the like is melted. This molten metal may fall and adhere to the valve wall, resulting in damage to the valve. The present invention has been made based on such a situation, and an object thereof is to prevent abnormal discharge from occurring between the ends of a filament when the filament is broken and prevent damage to the valve or the like. The present invention aims to provide a fluorescent lamp and a manufacturing method thereof.

[0006]

The fluorescent lamp of the present invention is characterized in that when the filament is broken, the filament is provided with a tension such that the broken ends are separated from each other by, for example, 1.0 mm or more. To do. Further, the manufacturing method of the present invention is characterized in that, when the filament is bridged between the pair of lead wires, the end portion of the filament is fixed to the lead wire while the tension is applied to the filament in advance.

Further, according to another manufacturing method of the present invention, when the filament is laid between a pair of lead wires, the end portions of the filament are fixed to the lead wires in advance, and the interval between the lead wires is widened in this state. It is characterized in that tension is applied to the filament.

[0008]

In the fluorescent lamp of the present invention, when the filament is broken, the broken ends are separated from each other by, for example, 1.0 mm or more, so that abnormal discharge is prevented from occurring between the broken ends. Further, the production method of the present invention can easily apply the initial tension to the filament.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. FIG. 1 shows an end portion of a fluorescent lamp, and reference numeral 1 in the drawing is a glass bulb. The end portion of the valve 1 is airtightly closed by a flare stem 2, and a pair of lead wires 3, 3 made of nickel or the like are airtightly penetrated through the stem 2. These lead wires 3, 3
A filament 4 is laid over the inner end of the. The filament 4 is made of a tungsten wire and is formed into a double coil or a triple coil. The leg portions 5 and 5 at both ends of the filament 4 are held by hook portions 6 formed on the lead wires 3 and 3.

In this case, the filament 4 is applied with a tension to stretch it in the axial direction. As shown in FIG. 2, when the filament 4 is broken, the tension is set to a strength such that the distance L between the ends of the break is 1.0 mm or more. The filament 4
As shown in FIG. 3, before applying the filament 4 between the lead wires 3 and 3, the leg portions 5 and 5 at both ends of the filament 4 are held by a pair of chucks (not shown), respectively. These chucks are separated to apply tension to the filament 4, and in this state, the leg portions 5 and 5 are clamped by the hook portions 6 and 6 formed on the lead wires 3 and 3.

Another method for applying tension to the filament 4 is to clamp the leg portions 5 and 5 at both ends of the filament 4 by the hook portions 6 and 6 of the lead wires 3 and 3, as shown in FIG.
In this state, if the pair of lead wires 3 and 3 are deformed so as to be separated from each other, a tension is applied to the filament 4. In FIGS. 1 and 2, reference numeral 7 is a phosphor coating formed on the inner surface of the bulb 1, and 8 is an exhaust pipe.

In the fluorescent lamp having such a structure, the filament 4 is excessively loaded at the end of its life, when it is shocked or vibrated, when it is erroneously used, or when it is lit by a high voltage, and the filament 4 is loaded. May be broken as shown in FIG. At the time of such disconnection, the ends of the disconnection are separated from each other due to the tension applied in advance.
Therefore, no current flows through the filament 4 and the lamp goes out.

In this case, since the separation distance L of the broken portion of the filament 4 is set to 1.0 mm or more, the occurrence of sparks is prevented, and the occurrence of abnormal discharge can be reliably prevented. As a result, the electric current is prevented from flowing to the filament 4, abnormal heating of the filament 4 and melting of the lead wires 3 and 3 are prevented, so that the valve can be prevented from being damaged due to the fall of the molten metal.

Table 1 below shows the occurrence of abnormal discharge after filament breakage, using 10 lamps each, and each lamp is applied with 200V.

[0015]

[Table 1]

From the results shown in Table 1 above, filament 4
It is confirmed that if the separation distance L is 1.0 mm or more, sparks after disconnection are prevented and abnormal discharge is surely prevented in the disconnection part.

The fluorescent lamp of the present invention can be applied not only to the straight tube lamp but also to various other fluorescent lamps such as a ring shape, a U shape, a W shape and a saddle shape. As a means for applying tension to the filament 4, a lead wire may be formed of a shape memory alloy, and the lead wire may be deformed by heating by the first lighting to apply the tension to the filament 4.

[0018]

As described above, according to the fluorescent lamp of the present invention, since tension is applied to the filament, when the filament breaks, the broken ends are separated from each other, and the broken ends are separated from each other. Generation of abnormal discharge is prevented. Therefore, abnormal overheating of the filament, melting of the lead wire, and the like are prevented, and damage to the valve can be prevented. Further, according to the manufacturing method of the present invention, the initial tension can be easily applied to the filament.

[Brief description of drawings]

FIG. 1 is a sectional view of an end portion of a fluorescent lamp according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a case where the filament of the same example is broken.

FIG. 3 is a diagram illustrating a method of applying tension to a filament.

FIG. 4 is a diagram illustrating another method of applying tension to the filament.

[Explanation of symbols]

1 ... Valve 2 ... Stem 3 ...
Lead wire 4 ... Filament 5 ... Leg part 6 ...
Hook part

Claims (4)

[Claims] 1. A fluorescent lamp in which a filament is sealed at the end of a bulb, wherein a tension is applied to the filament so as to separate the broken ends from each other when the filament is broken. 2. The fluorescent lamp according to claim 1, wherein the tension applied to the filament is such that, when the filament is broken, the broken ends are separated from each other by 1.0 mm or more. 3. A method for manufacturing a fluorescent lamp in which a filament is sealed at the end of a bulb, wherein when the filament is suspended between a pair of lead wires, the end of the filament is pretensioned. A method of manufacturing a fluorescent lamp, characterized in that a lead wire is fixed to the lead wire. 4. A method for manufacturing a fluorescent lamp in which a filament is sealed at the end of a bulb, and when the filament is bridged between a pair of lead wires, the end of the filament is fixed to each lead wire in advance. A method of manufacturing a fluorescent lamp, characterized in that the tension between filaments is applied by widening the lead wires in this state.