JPH03280355A - Bulb - Google Patents

Abstract

PURPOSE:To prevent a flare stem seal end part from thermal deformation and/or failure due to soldering by using a heat insulative tube for covering an external lead to be soldered to the opening of the base shell of a bulb. CONSTITUTION:An external lead 4 is threaded through the seal end part of a flare stem 2 and soldered to the opening of a base shell 8. This external lead 4 is covered with a heat insulative tube 20. Thereby the heat from the soldering is hindered from being conducted to the seal end part of the flare stem 2 through the lead 4, and thus the seal end part is prevented from breakage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a bulb whose end is sealed with a flared stem and whose sealed end is covered with a cap.

(Prior art) The bulb of an incandescent light bulb or the outer tube bulb of a discharge lamp has a flared stem sealed at the end of the neck, and a screw-type cap is attached to the sealed end. .

The case of a conventional small discharge lamp will be explained based on FIGS. 3 and 4.

In the figure, reference numeral 1 denotes an outer bulb, which houses an arc tube 2 inside. As is well known, the arc tube has a pair of electrodes (not shown) and is supported by a support wire.

The open end of the neck portion of the outer bulb 1 is sealed with a flare stem 3. The support wires (not shown) are sealed to the flare stem 3, and a pair of external lead wires 4.5 connected to these support wires are led out. Note that 6 is an exhaust pipe.

A screw cap 7 is attached to the sealed end of the neck.
is crowned. The screw-type cap 7 includes a cap shell 8 made of nickel alloy or the like, and a top terminal (referred to as an eyelet terminal) 10 attached to the end of the cap shell 8 via an insulating material 9.

One external lead wire 4 is guided to the open end of the cap shell 8 between the outer surface of the sealed end of the valve 1 and the cap shell 8, and is soldered 11 to the open end of the cap shell 8.

The other external lead wire 5 is led from the center of the insulating material 9 to the top terminal 10 and is soldered to the top terminal 10.

Note that a base cement (not shown) is filled between the cap shell 8 and the valve 1 to join the cap 7 to the valve 1.

(Problem to be Solved by the Invention) In such a configuration, when attaching one of the external lead wires 4 to the open end of the cap shell 8 with the solder 11, the solder 11
The heat is transmitted through this external lead wire 4, and this external lead wire 4 becomes high in temperature.

At this time, there are many cases where the middle part of the external lead wire 4 touches the sealing part of the valve 1 and flare stem 3, that is, the sealing end point A shown in FIG. In some cases, thermal distortion occurred at point A at the sealed end, causing cracks.

Such racks caused leaks in the outer tube valve, resulting in poor quality.

Conventionally, there is a method in which the external lead wire 4 or 5 is covered with an insulating tube, but the purpose of this insulating tube is to electrically insulate the external lead wires 4 and 5 from each other. The one that covered the part facing point A was longer.

The present invention aims to provide a bulb in which cracks due to thermal distortion are prevented from occurring at point A of the sealed end of the bulb.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention seals the end of a valve with a flared stem, and the sealed end is provided with a screw-type screw-type valve having a shell and a top terminal. In a tube having a shaped cap, one of the pair of external lead wires led out from the flare stem is soldered to the opening of the cap shell, and the other is connected to the top terminal, One of the external lead wires connected to the opening is covered with a heat insulating tube at a position facing the sealed end of the flare stem.

(Function) According to the present invention, since one of the external lead wires connected to the opening of the cap shell is covered with a heat insulating tube, the heat from soldering passes through the external lead wire to the sealed end point A of the valve. This prevents cracks from being generated at point A at the sealed end due to thermal strain.

(Example) The present invention will be described below based on an example shown in FIG.

FIG. 1 shows a cross section of the main parts related to the present invention, and the overall configuration may be the same as that shown in FIG. 3, so a description thereof will be omitted.

In this embodiment, the open end of the neck portion of the outer valve 1 is sealed with a flare stem 3, and a pair of external lead wires 4.5 are led out from the flare stem 3. 4 is guided between the outer surface of the sealed end of the valve 1 and the cap shell 8 to the open end of the cap shell 8.
The other external lead wire 5 is connected from the center of the insulating material 9 to the top terminal 1o.
It is the same as the conventional method in that the top terminal 10 is connected to the top terminal 10 with a half 11''.

One of the external lead wires 4 soldered to the open end of the cap shell 8 is covered with a heat insulating tube 2o.

This thermal insulation tube 2o is connected to one of the external lead wires 4
The valve 1 and the flare stem 3 are completely covered up to a point beyond point A of the sealed end.

In such a configuration, one of the external lead wires 4
When attaching the solder 11 to the open end of the cap shell 8,
The heat of 1111 is transmitted through this external lead wire 4 to the valve 1.
Even if the signal is to be transmitted to the point A of the sealed end of the knob 1, the point A of the sealed end of the knob 1 is never gets heated.

Therefore, problems such as thermal distortion at point A of the sealed end and generation of cracks are prevented, and leakage in the outer bulb 1 is prevented.

Moreover, the thermal insulation tube 2 is placed over one of the external lead wires 4.
0 electrically insulates between the one external lead wire 4 and the other external lead wire 5, so there is no fear that the two will be short-circuited.

Moreover, the above effects can be obtained with a simple structure of just covering the conventional structure with the heat insulating tube 20, and the cost is reduced.

In the above embodiment, the heat insulating tube 20 was covered from the lead-out root of one of the external lead wires 4 to the point beyond the sealed end point A, but as in the other embodiment shown in FIG. The heat insulating tube 30 may cover substantially the entire length of one of the external lead wires 4.

In this way, the thermal insulation effect from the external lead wire 4 to the knob l will be further enhanced.

Further, the present invention is not limited to the outer bulb of a discharge lamp, but can also be implemented in a normal incandescent light bulb.

[Effects of the Invention] As explained above, according to the present invention, one of the external lead wires connected to the opening of the cap shell is covered with a heat insulating tube, so that the heat from soldering is transferred to the valve through the external lead wire. This prevents the heat from being transmitted to point A at the sealed end, and prevents cracks from occurring at point A at the sealed end due to thermal strain.

Therefore, valve leakage is prevented and quality reliability is improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a valve end showing an embodiment of the present invention;
FIG. 2 is a sectional view of the end of the valve showing another embodiment of the present invention, and FIGS. 3 and 4 illustrate the conventional technology.
FIG. 3 is a side view showing the schematic structure of the discharge lamp, and FIG. 4 is a sectional view showing the end of the outer bulb. 1... Outer pipe valve, 3... Flare stem, 4, 5.
...External lead wire, 7...Base, 8...Shell, 0...Top terminal, 20, 0...Heat insulation tube.

Claims (1)

[Claims] The end of the valve is sealed with a flared stem, the sealed end is covered with a screw-type cap having a shell and a top terminal, and a pair of external lead wires are led out from the flared stem. In a tube, one of which is soldered to the opening of the cap shell and the other connected to the top terminal, one of the external lead wires connected to the opening of the cap shell is connected to the flare stem. A bulb characterized by having a heat insulating tube covered at a position facing the sealed end.