JPH01186548A - Manufacture of tubular incandescent lamp - Google Patents

Abstract

PURPOSE:To give no adverse effect to the coil pitch of a luminous section on the end section side by providing a coil-shaped close coiling section at one end of a filament, inserting one end section of an inner lead bar into the coil of the close coiling section, and welding only the side end section of the insertion port of the close coiling section to the inner lead bar. CONSTITUTION:Coil-shaped close coiling sections 23 are provided on both ends of a filament 20. One inner lead bar 30 is inserted into the coil of one of the close coiling sections 23, only the side end section 23A of the insertion port of the close coiling section 23 is welded and fixed to the inner lead wire 30. The other inner lead bar 30 is likewise fixed to the other close coiling section 23 to form a filament assembly body 20A. The assembly body 20A is inserted and arranged in a vertically held sealing glass tube 10, the tensile force in the axial direction of the glass tube 10 is applied to the filament 20, the end section 10A of the glass tube 10 is heated to form a pinch seal section. The portion except the side end section of the insertion port of the close coiling section is made slidable against the inner lead section, and no adverse effect is given to the coil pitch of the luminous section on the end section side of the filament.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a tubular incandescent light bulb with a foil seal structure.

[Technology background]

For example, in an example of a tubular incandescent light bulb with a double-end foil seal structure used as an exposure light source for a copying machine, light-emitting parts and non-light-emitting parts are arranged alternately within the tubular envelope. A partially emissive filament is stretched between a pair of internal lead rods connected to metal foil embedded in pinch seals at both ends.

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

Such tubular incandescent light bulbs have conventionally been manufactured through the following pinch sealing process. In other words, a so-called partially emissive filament in which a light emitting part made of a tightly wound coil and a non-light emitting part connecting the light emitting parts are arranged alternately;
A filament assembly consisting of an internal lead rod connected to both ends, a metal foil connected to the internal lead rod, and an external lead rod connected to the metal foil is produced, and this filament assembly is sealed. Insert it into the glass tube for
While applying a tensile force to the filament in the axial direction of the glass envelope tube, one end of the glass tube for the envelope is heated and pinch sealed to form one pinch seal portion in which one of the metal foils is embedded. The other pinch seal portion is formed in the same manner.

[Problem to be solved by the invention]

However, in such conventional manufacturing methods, when forming the pinch seal part, the filament is heated and pinch sealed with tensile force applied to it, so the coil pitch of the light emitting part on the end side of the filament widens. As a result, there was a problem that the light distribution was disturbed.

The present invention has been made based on the above circumstances, and it is possible to manufacture a tubular incandescent light bulb with a foil seal structure without adversely affecting the coil pitch of the light emitting part on the end side. The purpose is to provide a manufacturing method for.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a metal foil embedded in the pinch seal portions at both ends of a tubular enclosure, an internal lead rod connected to the metal foil, and a tension between these internal lead rods. A method for manufacturing a tubular incandescent light bulb with a foil seal structure, which includes a filament consisting of a light-emitting part and a non-light-emitting part, in which a tightly wound coiled part is provided at one end of the filament, and the coil of the tightly wound part is Insert one end of the internal lead rod into the inner lead rod, weld and fix only the end of the tightly wound part on the insertion port side to the internal lead rod, and apply a tensile force to the filament. It is characterized by heating and pinch-sealing the end portion of the metal foil to form a pinch-sealed portion in which the metal foil is embedded.

[Effect]

Since only the end of the tightly wound coiled portion on the insertion port side is welded and fixed to the internal lead rod, the portion of the tightly wound portion other than the end on the insertion port side can slide relative to the internal lead rod. Become. Therefore, in the pinch sealing process, when heating the filament while applying a tensile force, the portion of the tightly wound coiled portion excluding the end on the insertion port side slides and the thermal expansion force is absorbed.

〔Example〕

The present invention will be explained in detail below.

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

The light-emitting part 21 is formed of a tightly wound coil made of, for example, tungsten, and the non-light-emitting part 22 is formed by, for example, a short-circuiting rod 23 in a loosely wound connecting coil integrally provided at the end of the light-emitting part 21.
are inserted and connected. 24 is a ring-shaped supporter formed integrally with the shorting rod 23.

The tightly wound portion 23 is provided integrally with the light emitting portion 21 on the end side, has the same coil pitch as the light emitting portion 21, and has a winding number of approximately 20 to 25 tanns, for example.

Next, as shown in FIG. 2, one of the internal lead rods 30 is inserted into the coil of one of the tightly wound portions 23, and only the insertion opening side end 23A of the tightly wound portion 23 is welded to the internal lead rod 30. and fix it. In this welding, the internal lead rod 30 and the metal foil 40 made of, for example, molybdenum can be simultaneously welded. 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 2OA. 50 is an external lead rod.

Next, as shown in FIG. 3, the filament assembly 2OA is inserted into the glass envelope tube 10 held almost vertically, and the filament 20 is filled with a glass envelope tube weighing, for example, about 10 to 20 g. By heating and pinch-sealing the end 10A of the glass tube 10 for sealing while applying a tensile force in the direction of the tube axis of 10, one metal foil 40 is attached to the end as shown in FIG. A pinch seal portion 11 is formed embedded within the glass. Then, the glass sealing tube 10 is turned upside down and the other pinch seal portion is formed in the same manner.

According to the embodiments described above, in the process of forming the pinch seal portion, the other end of the glass tube 10 for sealing is heated and pinch-sealed while applying a tensile force to the filament 20. Since the tightly wound portion 23 is welded to the internal lead rod 30 only at its insertion port side end 23A, the portion of the tightly wound portion 23 excluding the insertion port side end 23A slides with respect to the internal lead rod 30. Therefore, the thermal expansion force due to heating is absorbed by the sliding displacement of the tightly wound part 23 which has a higher temperature than the light emitting part 21 on the end side of the filament 20, and the coil of the light emitting part 21 on the end side of the filament 20 It does not adversely affect the pitch. Therefore, a tubular incandescent light bulb with a good light distribution can be manufactured without causing any disturbance in the light distribution.

[Function and effect of the invention]

According to the present invention, a coiled close-wound portion is provided at one end of the filament, one end of the internal lead rod is inserted into the coil of the close-wound portion, and only the end of the close-wound portion on the insertion port side is inserted into the coil. Since it is fixed by welding to the lead rod, the part of the tightly coiled coiled part except for the end on the insertion port side can slide against the internal lead rod, so it is possible to apply tensile force to the filament during the pinch sealing process. When heating in this state, the part of the tightly wound coiled part other than the end on the insertion port side slides and the thermal expansion force is absorbed, resulting in an adverse effect on the coil pitch of the light emitting part on the end side of the filament. is prevented, and a predetermined light distribution can be reliably obtained. Incidentally, since the tightly wound portion is short-circuited by the internal lead rod, light emission is prevented.

[Brief explanation of the drawing]

FIGS. 1 to 4 are explanatory diagrams showing the manufacturing method of the present invention in order of steps. 10...Glass tube for sealing body 10A...End part 11.
...Pinch seal part 20...Filament 2OA
...Filament assembly 21...Light-emitting part 22...Non-light-emitting part 23
...Tightly wound part 23A...Insertion port side end 3
0... Internal lead rod 40... Metal foil 50...
・External lead rods! Decoy 2 figure 0A

Claims (1)

[Claims] 1) A metal foil embedded in the pinch seal portions at both ends of the tubular enclosure, an internal lead rod connected to the metal foil, and a wire stretched between these internal lead rods. , a method for manufacturing a tubular incandescent light bulb with a foil-sealed structure comprising a filament consisting of a light-emitting part and a non-light-emitting part, in which a tightly wound part in a coil shape is provided at one end of the filament, and an inner part is inside the coil of the tightly wound part. Insert one end of the lead rod, weld and fix only the end of the tightly wound part on the insertion port side to the internal lead rod, and apply a tensile force to the filament, then insert the end of the glass tube for the seal. A method for producing a tube-shaped incandescent light bulb, which comprises heating and pinch-sealing to form a pinch-sealed portion in which metal foil is embedded.