JP2641126B2 - Manufacturing method of tubular incandescent lamp - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a tubular incandescent lamp having a foil seal structure.

[Technological background]

For example, in an example of a tube-shaped incandescent lamp having a bubble-end type foil seal structure used as a light source for exposure of a copier, light-emitting portions and non-light-emitting portions are arranged alternately in a tube-shaped envelope. A partially luminous filament is stretched between a pair of internal lead rods connected to a metal foil embedded in pinch seal portions at both ends.

Therefore, in order to obtain an appropriate light distribution, it is necessary that the light emitting portion of the filament is arranged at a predetermined position in the tubular envelope.

Conventionally, such a tubular incandescent lamp has been manufactured through the following pinch sealing process. That is, a so-called partial light-emitting filament in which light-emitting portions formed of closely-wound coils and non-light-emitting portions connecting the light-emitting portions are alternately arranged, an internal lead rod connected to both ends of the filament, and the internal lead rod. To produce a filament assembly consisting of a metal foil connected to, and an external lead rod connected to the metal foil,
This filament assembly is inserted and placed in a glass tube for sealing, and one end of the glass tube for sealing is heated and pinch-sealed while a tensile force is applied to the filament in the axial direction of the glass tube for sealing, so that one of the filaments is sealed. One pinch seal portion in which the metal foil is embedded is formed. Similarly, the other pinch seal portion is formed.

[Problems to be solved by the invention]

However, in such a conventional manufacturing method, when the pinch seal portion is formed, the filament is heated and pinch-sealed in a state where a tensile force is applied to the filament, so that the coil pitch of the light emitting portion on the end side of the filament is widened. As a result, there is a problem that the light distribution is disturbed.

The present invention has been made based on the above circumstances, and is capable of manufacturing a tube-shaped incandescent lamp having a foil-sealed structure without adversely affecting a coil pitch of a light emitting portion on an end portion. It is an object of the present invention to provide a method for producing the same.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a metal foil embedded in pinch seal portions at both ends of a tubular envelope, an internal lead rod connected to the metal foil, and a tension between these internal lead rods. In a method for manufacturing a tubular incandescent lamp having a foil seal structure comprising a light-emitting portion and a filament formed of a non-light-emitting portion, a coil-shaped close winding portion is provided at one end of the filament, and the coil of the close winding portion is provided. By inserting one end of the internal lead rod into the inside, and welding and fixing only the insertion port end of the tightly wound portion to the internal lead rod, a portion excluding the insertion port end of the close wound portion Is slidable with respect to the internal lead rod, and the end of the glass tube for sealing is heated and pinch-sealed while a tensile force is applied to the filament to form a pinch seal portion in which a metal foil is embedded. Features to To.

[Action]

Since only the insertion-port-side end of the coiled tightly-wound portion is fixed to the internal lead rod by welding, the portion of the close-wound portion excluding the insertion-port-side end can slide with respect to the internal lead rod. Become. Therefore, in the pinch sealing step, when the filament is heated in a state where a tensile force is applied, the portion of the coil-shaped tightly wound portion other than the insertion opening side end slides to absorb the thermal expansion force.

〔Example〕

 Hereinafter, embodiments of the present invention will be described.

As shown in FIG. 1, the filament 20 is formed by alternately connecting the light emitting portions 21 and the non-light emitting portions 22. Then, coil-shaped densely wound portions 23 are provided at both ends of the filament 20.

The light-emitting portion 21 is formed of, for example, a close-wound coil made of tungsten, and the non-light-emitting portion 22 is connected, for example, by inserting a short-circuit rod 25 into a coarse-winding connection coil provided integrally at an end of the light-emitting portion 21. It has been formed. Reference numeral 24 denotes a ring-shaped supporter integrally formed with the short-circuit bar 25.

The densely wound portion 23 is provided integrally with the light emitting portion 21 on the end side,
It has the same coil pitch as the light emitting unit 21 and the number of turns is, for example, 20
About 25 turns.

Next, as shown in FIG. 2, one of the internal lead rods 30 is inserted into the coil of one of the closely wound portions 23, and only the insertion port side end 23A of the closely wound portion 23 is inserted into the internal lead rod 30. To the insertion port side end 23 of the tightly wound portion 23.
The portion excluding A is slidable with respect to the internal lead rod 30. In this welding, the inner lead rod 30
And welding with a molybdenum metal foil 40, for example. Then, the other internal lead rod 30 is fixed to the other tightly wound portion 23 in the same manner as described above, thereby producing the filament assembly 20A. 50 is an external lead rod.

Next, as shown in FIG. 3, the filament assembly 20A is inserted and arranged in the glass tube 10 for sealing which is held substantially vertically, and for example, the glass tube 10 for sealing of about 10 to 20 g is attached to the filament 20. In a state where a tensile force is applied in the direction of the tube axis, the end portion 10A of the glass tube 10 for sealing is heated and pinch-sealed, so that one of the metal foils 40 has an end portion as shown in FIG. A pinch seal portion 11 embedded in the glass is formed.
Then, the other glass pinch seal is formed by inverting the glass tube 10 for sealing in the same manner.

According to the above-described embodiment, in the step of forming the pinch seal portion, the end portion of the glass tube 10 for sealing is heated and pinch-sealed while the filament 20 is given a tensile force.
The tightly wound portion 23 provided on the filament 20 is
A is welded to the internal lead rod 30 only, and the portion of the close-wound portion 23 except the insertion port side end 23A is slidable with respect to the internal lead rod 30. Is absorbed by the sliding displacement of the densely wound portion 23, which is higher in temperature than the light emitting portion 21 of the
Does not adversely affect the coil pitch of the light emitting section 21 on the end side of the light emitting section. Therefore, the light distribution is not disturbed, and a tubular incandescent lamp having a good light distribution can be manufactured.

〔The invention's effect〕

According to the present invention, a coil-shaped closely wound portion is provided at one end of the filament, one end of the internal lead rod is inserted into the coil of the closely wound portion, and only the insertion port side end of the closely wound portion is connected to the coil. By welding and fixing to the internal lead rod, a portion of the close-wound portion except for the end on the insertion port side is slidable with respect to the internal lead bar, so that the insertion opening of the coil-shaped close-wound portion is The portion excluding the side end portion is slidable with respect to the internal lead rod. Therefore, when the filament is heated in a state where a tensile force is applied to the filament in the pinch sealing process, the insertion end portion of the coil-shaped tightly wound portion is inserted. The portion other than the filament slides to absorb the thermal expansion force, thereby preventing the coil pitch of the light emitting portion on the end side of the filament from being adversely affected, and a predetermined light distribution can be reliably obtained. Since the close winding portion is short-circuited by the internal lead rod, light emission is prevented.

[Brief description of the drawings]

1 to 4 are explanatory views showing the manufacturing method of the present invention in the order of steps. 10: Glass tube for sealing, 10A: End 11: Pinch seal part, 20: Filament 20A: Filament assembly 21: Light emitting part, 22: Non-light emitting part 23: Closely wound part, 23A Insert end 25 Short-circuit bar 30 Internal lead bar 40 Metal foil 50 External lead bar

Claims (1)

(57) [Claims] 1. A metal foil buried in pinch seal portions at both ends of a tubular envelope, an internal lead rod connected to the metal foil, and a light emitting section stretched between the internal lead rods. And a filament comprising a non-light-emitting portion and a filament comprising a foil-sealed structure, comprising: a coil-shaped close-wound portion at one end of the filament; and an internal lead rod inside the coil of the close-wound portion. One end is inserted, and only the insertion-port-side end of the close-wound portion is welded and fixed to the internal lead rod, so that the portion of the close-wound portion excluding the insertion-port end is fixed to the internal lead bar. A tube characterized in that the end portion of the glass tube for sealing is heated and pinch-sealed by applying a tensile force to the filament to form a pinch seal portion in which a metal foil is embedded. Manufacture of incandescent light bulbs Method.